Anabolic Agents and Meat Quality Patterson1985

Meat Science 14 (1985) 191-220

Anabolic Agents and Meat Quality: A Review

R. L. S. Patterson & Linda J. Salter

AFRC Meat Research Institute, Langford, Bristol. Great Britain

(Received: 9 November, 1984)

SUMMARY

This review considers the results of more than sixty studies on the possible effects of anabolic agents on the meat quality parameters of the three main red meat species and poultry. The information is grouped into three main sections: carcass composition, muscle qualio' and eating quality. Each section is further divided by animal species, with consideration given to differences due to sex or age.

Anabolic agents appear to have some effect on the carcass composition of animals; depending upon the type used, the)' can cause an increase in the ratio of muscle to fat #1female and castrate animals, or a decrease in this ratio in entire males. Such differences are usually reflected in related changes in the chemical composition of the meat. Few consistent effects, however, have been reported in the eating quality oJ'the cooked meat in terms of texture, flavour, juicbwss or cooking loss, indicating that the basic eating quality attributes important to the consumer are largely unaffected by hormone treatment.

INTRODUCTION

The volume of scientific literature describing the application of growth- promoting substances to animal production is large but can be sub- divided into areas of particular scientific interest, such as the overt effects on growth, changes in metabolism, blood serum and tissue levels, residue

191 Meat Science 030%1740/85 $03-30 ( Elsevier Applied Science Publishers Ltd, England, 1985. Printed in Great Britain

192 R. L. S. Patterson. Linda J. Salter

problems, development of analytical techniques and carcass and eating quality factors. This paper deals only with these last two aspects. Even with this restriction of subject area, the review which follows is not fully comprehensive, but presents the summarised results of more than sixty studies on the effects of anabolic agents on the quality parameters of the three main red meat species and poultry.

The term 'growth promoter' can refer to more than one type of substance used in animal production, e.g, antimicrobial agents, thyrostats, anthelmintics and anabolic agents. This review, however, considers only anabolic agents, which are generally hormonal in action. It is thought that they achieve their effect by causing a net increase in nitrogen retention in the form of muscle protein. Net protein deposition is controlled by both anabolic and catabolic processes: the effect ofanabolic agents is complex and the exact mode of action remains obscure. Anabolic agents can either be classified according to whether they are oestrogenic, androgenic or progestagenic in action, or by whether they are steroids which are endogenous to farm animals, or are exogenous steroidal or non-steroidal compounds: these latter are sometimes referred to as xenobiotics. The substances most commonly used to promote growth have included oestradiol-17[~, oestradiol-17/3-benzoate, oestradiol-17/l-pahnitate, progesterone, testosterone, testosterone pro- pionate, methyltestosterone, trenbolone acetate, zeranol, hexoestrol, diethylstilboestrol, dienoestrol diacetate and melengesterol acetate.

The legislation employed by different nations concerning the use of anabolic agents varies widely, even between member states of the EEC, and a detailed discussion of the policies followed by individual countries would be inappropriate in the context of this review. However, a brief consideration of the international situation, as it stands at present, may be of relevance and interest to the reader.

The anabolic agents currently permitted by the EEC are those based upon the naturally occurring hormones (oestradiol- 17/3, testosterone and progesterone) and two xenobiotics, trenbolone acetate and zeranol, following an EEC Directive in 1981 (81/602/EEC) which banned the use of stilbenes and thyrostats as growth promoters. However, trenbolone acetate and zeranol have not passed investigation by the Scientific Working Party on Anabolic Agents in Animal Production (formed as a result of the above Directive) as sufficient information from toxicological studies has not been available. For this reason, the EEC Commission plans to impose a ban on these two agents, dating from 1 July, 1985.

Anabolic agents and meat quality: a review 193

Additionally, some member countries have independently imposed complete, or partial, bans on the use of anabolic agents in meat production.

Anabolic agents are also used extensively in many countries outside the EEC (Storie-Pugh, 1984). The US Food and Drug Administration has cleared oestradiol-I 7//, testosterone, progesterone and zeranol for use in beef production for the US market, and a large number of other countries, including Canada and Australia, permit the use of the three naturally occurring hormones, as well as trenbolone acetate and/or zeranol.

Although the highly oestrogenic stilbenes are now banned from use for the fattening of meat animals, a considerable proportion of research over the past two or three decades has been conducted using such substances: hence, much of the information about the effect on animal growth and carcass composition available today is based upon the effects of these and similar compounds. In the review which follows, the information has been grouped into three main sections: (i) carcass composition. (ii) muscle quality and (iii) eating quality. Each section is further divided by animal species, with additional sub-divisions, where appropriate, to accom- modate different responses due to sex or age differences in the treated animals: for example, bulls, steers or veal calves. As far as possible, treatment types, i.e. androgenic or oestrogenic, have been kept together within these sub-heads, and the names of the applied agents emphasised in bold type to facilitate reference. No attempt has been made to give fully detailed results for each paper listed; the salient points have been identified and should direct readers to the appropriate research if further information is required.

CARCASS COM POSITION

Cattle

Sgeel's

None of the work recording zeranol treatment of steers reported any change in the gross composition (estimated or total): 04, lean, fat and bone in either the 9th-I lth rib region or in the whole carcass (Ntunde et al., 1977), loin eye area (Sharp & Dyer, 1971; Cohen & Cooper, 1983), ~/o kidney and pelvic fat (Borger et al., 1973a: Ntunde et al., 1977),

194 R. L. S. Patterson, Linda J. Salter

various measures of fat cover (Sharp & Dyer, 1971 ; Borger et al., 1973a; Ntunde et al., 1977; Cohen & Cooper, 1983), the lean:fat ratio and the lean:bone ratio (Ntunde et al., 1977) were all unaltered. Roche (1980) found that treatment with zeranoi or zeranol + trenbolone acetate caused no change in ~ lean, fat or bone, while Scott (1978) reported that no significant change in composition occurred on treatment with trenbolone acetate, zeranol or trenbolone acetate + hexoestroi. However, in two trials, Griffiths (1982) found that the use of trenbolone acetate + zeranol significantly increased the proportion of lean meat in the carcass (P < 0.05, 0.01, respectively), while the dissectable fat was decreased (NS, P < 0.05), as was the proportion of bone and connective tissue (P < 0.01, NS).

Work by Wood & Fisher (1983) using twin calves showed that steers implanted twice with trenbolone acetate+ oestradiol-17fl yielded carcasses with proportions of lean and fat slightly closer to those found in bulls, i.e. leaner and less fat than untreated steers.

Simone et al. (1958) reported no change in ~,,, lean, fat or bone following the administration of diethylstUboestrol, either orally or by implantation, while Ogilvie et al. (1960) found that the oral administration of 30 mg diethylstilboestrol per day significantly increased rib eye area (P < 0.01) and also decreased the depth of fat covering the 12th rib, although not significantly. There was no effect on ~,,, bone.

Treatment of steers with oestradiol-17fl has yielded conflicting results. Mathison & Stobbs (1983) reported that, although the fat depth was not significantly altered, rib eye area was increased (P < 0-05) by implantation with oestradiol-17fl. However, Utley et al. (1980) found that various types of oestradiol-17fl implant caused no significant differences in heart, kidney and pelvic fat, rib eye area or rib eye fat, although they tended to decrease rib eye area and increase fat scores. Schanbacher et al. (1983) used silastic implants of oestradiol- 17fl-dipropionate which reduced (P < 0.05) longissimus area in both bulls and steers: adjusted backfat thickness was also slightly reduced in steers.

Rumsey (1982) found no significant alteration in rib eye area, fat over the rib eye or kidney, pelvic and heart fat following treatment with progesterone + oestradiol-17fl-benzoate, although implanted steers tended to have a greater rib eye area. The same preparation was found by Prior et aL (1978) to significantly reduce (P < 0.05) ~ kidney and pelvic fat, but there was no alteration to adjusted fat thickness orlongissimus area.

Thus, it appears that hormone treatment of steers (with trenbolone


acetate + zeranol, diethylstilboestrol, oestradiol-17/~ or progesterone + oestradioi-17/~-benzoate) sometimes increases the levels of lean meat and decreases the amount of fat in the carcass or selected portions, although this effect is not always statistically significant and was not observed for zeranol alone. These conclusions are in general agreement with those drawn by Galbraith & Topps (1981) in their review concerning the effect of various hormone treatments (diethylstiiboestrol, hexoestrol, progesterone + oestradiol-17/~-benzoate and testosterone) on the carcass composition of steers.

Bulls Opinion differs as to whether the administration of diethylstilboestrol to bulls affects the quantity of dissectable fat deposited, Williams et al. (1975a) found that diethylstilboestrol-implanted bulls had significantly (P


the adjusted fat thickness was significantly (P < 0-05) increased and the ~o kidney, pelvic and heart fat showed a small, non-significant, change in the same direction. Johnson et al. (1984) reported that bulls implanted with zeranoi showed no significant change in fat thickness (12th rib), adjusted fat thickness, estimated ~ kidney, pelvic and heart fat or longissimus area. Carcasses from bulls implanted with progesterone + oestradiol-17/3- benzoate had significantly (P < 0.05) greater fat thickness than those from control bulls: when actual fat thickness was adjusted for variations in fatness in other regions of the carcass, the oestradiol-17/~-treated bulls also showed a significant (P < 0.05) increase in fatness. The other carcass parameters were unaffected by these two treatments. These studies indicated that oestrogenic substances tend to increase the amount of fat deposited, although the effect was rarely significant. No significant changes in the degree of muscling were observed.

Gielen et al. (1982) found that a combination of trenbolone acetate + oestradiol-17fl increased (P < 0.05) the 9o connective tissue plus fat when used at the beginning of a period of growth at pasture and decreased "//o bone both during the growth and fattening periods (P < 0.05, 0.0 l, respectively), as determined by dissection of the 7th right rib. However, conflicting results were obtained in a later study (Lambot et al., 1983) which indicated that the same hormones caused a significant (P < 0.05) rise in ~,, bone, while the ~,,, connective tissue plus fat and the ~o muscle were slightly decreased, and raised, respectively, although not significantly so. Results obtained by Wood & Fisher (1983) showed that in bull pairs, the ones treated with this combination of hormones contained more fat (P < 0.05) than their untreated twin. Thus, it seems that one effect of these hormones, like the purely oestrogenic treatments, is to increase the proportion of fat deposited.

Interestingly, a study by Price et al. (1983) suggested that zeranol may reduce the incidence of dark cutting in bull carcasses; although the results did not reach statistical significance, only 10 '~ of the implanted bulls were graded as dark cutting compared with 40'y,,, of the controls.

Johnson et al. (1984) also compared the above-mentioned traits for Hereford x Angus, Hereford and Charolais-cross bulls in the same trial: fewer differences were noted between implanted and control animals than were observed between the different breeds. For Hereford bulls it was noticed that, while control carcasses were all assigned to the sex-class "bullock', all the implants produced more (P < 0-05) carcasses which were classed as'steer ' , perhaps indicative of some retardation of the development of masculine characteristics.


Veal calves Implantation of veal calves (young bulls) with trenbolone acetate + oestradiol-17/3, on two separate occasions, significantly (P < 0-01) increased the %'total meat' and reduced the % fat in the 3rd rib cut: a decrease (P < 0.05) was also noted in % bone (Verbeke el al., 1975). A single implant gave similar changes, although only the % total meat showed a significant alteration (P


gilts in four out of five trials; in one of these, he noted that the reduction was greater for barrows than gilts, and also for pigs on low protein (12 ~o), rather than high protein (16 ~), rations. Plimpton & Teague (1972) noted a significant (P < 0.05) decrease in backfat for barrows but not for gilts.

Barrows implanted with oestradiol-17fl + trenbolone acetate and those given orally administered ethynyloestradiol + trenbolone acetate showed significant (P< 0-01) reductions in backfat compared with controls (Grandadam et al., 1975; van Weerden & Grandadam, 1975).

The results of a number of trials conducted by Bidner et al. (1972a,b) indicated that oral administration of diethylstilboestrol + methyltestosterone caused small, largely non-significant, increases in the area of the M. longissimus dorsi for both barrows and gilts. Plimpton & Teague (1972) noted a significant (P < 0-05) increase in longissimus muscle area for similarly treated barrows but there was a small, non-significant, decrease for gilts. Increases in ~o lean cuts in pigs treated with diethylstilboestrol +methyltestosterone were noted by Bidner et al. (1972a) which were more pronounced in barrows than gilts, while their later paper (Bidner et al., 1972b) showed similar, but non-significant, increases. Plimpton & Teague (1972) also reported a significant increase (P < 0-05)in the ~ lean cuts of barrows but not ofgilts. Lucas et al. (1971) found the same result in one of five experiments whilst, in another, ~o lean cuts were increased in both sexes. The same authors found no consistent increase in loin eye area, in contrast to the marked reduction in backfat, and suggested that this was evidence for an antilipogenic, rather than an anabolic, mode of action in this case. Such treatment also resulted in heavier bones but their composition was similar to that of the controls (Bidner et al., 1972a). Fowler (1975) reported that ethynyloestradiol also gave large increases in the growth rate of lean tissue. Androgens had little effect when used alone but did improve the response to oestrogens.

In several experiments with boars, Plimpton & Teague (1972) found that implantation with diethyistilboestrol increased backfat thickness, sometimes significantly. However, their 'leanness' was still better than that of untreated littermate barrows. M. longissimtts dorsi area and lean cuts were not significantly altered. Ockerman et al. (1981) found that such treatment resulted in carcasses from heavyweight boars that did not differ significantly in ham, shoulder or loin weight or in M. longissimus dorsi area from normal boars or castrates; however, a small, non- significant, decrease in lean cuts between control and implanted boars was noted.


Galbraith & Topps (1981) cited a number of cases where various hormones (methyltestosterone, with and without diethylstilboestrol or ethynyloestradiol, and trenbolone acetate +oestradiol-17~ have been shown to increase leanness and protein content and to decrease fat content in barrows and gilts. When administered alone, diethylstilboestrol and ethynyloestradiol have sometimes stimulated the growth of lean tissue, while in other studies no effects were observed. Implantation of young boars with diethylstilhoestrol increased carcass fat and decreased the yield of lean joints, but no effects were observed for animals weighing over 70 kg.

Sheep

Zeranol appears to have no effect on the gross composition of the carcass; fat thickness, kidney fat weight and M. longissimus dorsi area were not significantly altered by implantation in ram, cryptorchid, wether or ewe lambs (Wilson et al., 1972; Wiggins et al., 1976, 1979) and the weights of selected joints were unchanged in wethers (Wiggins et al., 1979). Wether lambs treated with hexoestrol have been shown to have more bone, more 'flesh' and less subcutaneous fat than controls (Galbraith & Topps, 1981). In contrast, diethylstilboestrol implanted in wethers, either alone or with zeranol, significantly (P < 0.05) increased fat cover but had no significant effect on longissimus area or ~ kidney fat. However, diethylstilboestrol was thought to be capable of increasing or decreasing fat deposition, depending on the calorie: protein ratio of the ration (Wiggins et al., 1976). Purchas (1973) discovered that the injection of wether and ewe lambs with melengesteroi acetate resulted in no differences in the following measures of meat composition: fat depth/carcass weight, omental fat/carcass weight, pelvic and perinephric fat/carcass weight, collective weight of(M. semitendinosus + M. semimembranosus + M. biceps fcmoris)/carcass weight and weight of the same three muscles/femur weight. Sulieman et al. (1983) reported that implantation of ewes with various amounts of trenbolone acetate significantly increased (P < 0-01) the weight of lean tissue and also raised the amount of intermuscular fat (P < 0-05), gut and caul fat (P < 0-01), and kidney and channel fat (P < 0-01). Thus, hormone treatment of sheep causes some small, but inconsistent, changes in carcass composition.

Poultry

A number of studies have investigated the effects of anabolic agents on


poultry, usually chickens, using the oestrogenic compounds oestradiol- 17fl-dipropionate (Akiba et al.. 1982). oestradiol-17fl-monopalmitate (York & Mitchell, 1969: Bassila et al., 1975" Moran & Etches, 1983), dienoestroi diacetate (Bassila et aL, 1975: Akiba et al., 1983), diethylstilboestrol (Bogdonoff et al., 1961" Donovan & Sherman, 1960) and hexoestrol (Ryley et al., 1970), and also the androgen methyltestosterone (Bogdonoff et al., 1961).

Ryley et al. (1970) reported that treatment of cockerels with hexoestrol induced significant changes in both the absolute and relative weights of numerous body components and organs: for example, the legs of treated birds were less heavy (P < 0.01) than those of controls. Both the absolute quantity and the o/ fat in the carcasses from treated cockerels were /o significantly (P < 0.001) increased. Bogdonoff et al. (1961) reported that diethylstilboestrol-treated cockerels had a hi~her o/fat at 9 weeks, while /o Donovan & Sherman (1960), who investigated the effects of implanting diethyistUboestrol in both male and female chickens, found that the ~o fat was significantly (P < 0-05) increased at 15 weeks of age.

Various workers have noted a significant reduction in ''/ moisture (Donovan & Sherman, 1960: York & Mitchell, 1969: Ryley et al., 1970), o//,, protein (Donovan & Sherman, 1960: Ryley et al., 1970) and ~/,, ash (Ryley et al., 1970) following oestrogen treatment: however, Ryley et al. (1970) found that in their work there was no change in the total moisture, protein or ash, and that the increased weight of fat accounted for all the increased body and carcass weight. They postulated that this extra fat deposition was the cause of the poorer food conversion by the treated birds.

In a study of the effect of oestrogenic substances on hepatic lipid deposition, implantation of oestradiol-17fl-dipropionate (Akiba et al., 1982) in 3-week-old male broiler chicks gave rise to increased (P < 0.001) liver weight, liver fat content and plasma lipids, and dienoestrol diaeetate (Akiba et al., 1983) included as a feed additive caused similar increases (P < 0"05).

The foregoing results agree with those reviewed by Galbraith & Topps (1981), which indicated that oestrogen treatment of poultry led to increased deposition of both subcutaneous and intramuscular fat which was judged to improve carcass quality.

Bogdonoff et ell. (1961) reported that the treatment of cockerels with the androgen methyltestosterone or with methyltestosterone +diethylstilboestrol sometimes caused an increase in /ash and a decrease in ~o /o


fat, but did not state whether these differences were statistically significant.

Oestradiol-17~-monopalmitate has been implanted in turkey toms at 8 weeks of age and was found to increase the extent of fleshing, breast and back 'finish" relative to controls (Moran & Etches, 1983). The composition of selected raw tissues supports these findings: the fat content of the back skin (shown to be correlated with finish grade) and the fat deposition in the thigh were significantly (P< 0-001, P


and an increase in ~o moisture in the longissimus muscle of zeranoi- treated steers compared with controls, but not for the adductor or intercostal muscles also studied, nor for the overall average. Sharp & Dyer (1971) found a significant (P < 0-05) reduction in % fat and a non- significant increase in ~ water for similarly treated steers fed on a diet Containing 18 ~ protein, while steers on 12 /o dietary protein showed similar, but non-significant, trends. Nute & Dransfield (1984) reported no significant differences in 9/0 moisture and ~ fat between treated and control meat, although the 9/0 fat was slightly decreased. Sharp & Dyer (1971) reported that meat from zeranoi-treated steers (on both 12 ~o and 18 ~ protein diets) showed significantly (P < 0.05) greater 9/0 protein levels than controls. However, Borger et al. (1973b) noted no significant differences in total nitrogen levels for meat from treated steers, while Nute & Dransfield (1984) reported no significant differences in ~,~ protein.

Hill (1966) reported that double hexoestrol implantation caused significantly (P < 0.05) higher moisture levels than those found in controls while fat levels were non-significantly lower. Single hexoestrol treatments gave results which were not significantly different to the controls, but there was a trend towards decreasing fat and increasing moisture in the order control-early-late-double-treated steers. Total nitrogen levels were also studied but no significant changes were found. Bryce-Jones et al. (1964) reported that hexoestroi resulted in a significantly (P < 0.05) lower ~ fat level but had no significant effect on

moisture or ~ nitrogen. Lawrie (1960) noted that although the 'Uo intramuscular fat in the M. longissimus dorsi was lowered in hexoestrol- treated steers, there was no alteration in ~ dry matter, ~o ash or ~o nitrogen. Furthermore, the distribution of nitrogen (between non- protein, sarcoplasmic, myofibrillar and stroma) was almost identical in the same muscle of control and implanted animals.

Simone et al. (1958) reported that diethylstilboestrol administration, o/ fat or either orally or by implantation, had no significant effect on /o

moisture, while Wierbicki et al. (1956) noted a reduction in the O/,o fat and a small rise in ~o moisture in meat following implantation with diethylstilboestrol. The oral administration of 30 mg diethylstilboestrol per day caused an increase in moisture and a decrease in fat compared with controls, which were significant (P


Griffiths (1982) reported that a combination of trenbolone acetate + zeranol caused the proportion of fat in the edible carcass to be significantly reduced whilst the proportion of water was increased (P < 0.05 for experiment 1 and P < 0-01 for experiment 2); the crude protein level was also increased (P < 0.05) in the first of these experiments.

Forrest (1975) reported that a combination of progesterone + oestradiol- 17/~-benzoate resulted in a reduction of ether extractable fat in the M. long&simus dorsi muscle of steers. Rumsey (1982), however, found no change in the ~o water while the ~o ether extractable fat in the carcass was non-significantly increased. However, there was a significant (P < 0-05) reduction in the proportion of nitrogen in the carcass.

It appears, therefore, that hormone treatment may cause a reduction in ~ fat and a small rise in the ~o moisture and protein of the meat. These findings would be expected from the effects on overall carcass composition: muscle from fatter animals has a higher ~o lipid. Such a conclusion is in agreement with that reached by Galbraith & Topps (1981), who, in their review, concluded that oestrogenic compounds (diethylstilboestrol, hexoestrol and zeranol) tended to increase ~ protein and ~o moisture, and decrease % fat. Of the work reviewed here only Rumsey (1982) reported results which actually contradict this trend, although, in a number of cases, no significant effects were observed. The results of Sharp & Dyer (1971) indicated that the increases in % moisture and protein were proportional, the ratio of the two being little changed. So, in this case at least, the increased % protein and moisture could be attributed simply to the decrease in % fat.

Three authors (Bryce-Jones et a/., 1964: Rumsey, 1982; Nute---& Dransfield. 1984) have reported that treatment of steers with various hormones caused no significant change in the levels of fat-free dry matter in the muscle. Hill (1966) and Nute & Dransfield (1984) reported no significant changes in collagen levels (found by determination of hydroxyproline) for hormone-treated steers, in contrast to Wierbicki et a/. (1956), who reported that hydroxyproline levels were higher in meat from treated cattle. The same authors also found little difference in pH (measured 3 and 13 days post mortem) in treated versus control steers, whilst Nute & Dransfield (1984) reported no change in the pH of homogenised muscle. The energy content of the carcass (Mcal/kg) was not significantly altered by hormone treatment (Rumsey, 1982).

Borger et al. (1973a), Ntunde et al. (1977) and Cohen & Cooper (1983) reported that zeranol treatment of steers had no significant effect on the subjective marbling scores for the meat. Marchello eta/. (1970), however,


found that diethylstilboestrol-treated cattle had lower marbling scores than did controls (where 'cattle" included both steers and heifers) while Rumsey (1982) reported slightly, but not significantly, higher marbling scores for steers treated with progesterone+oestradiol-17fl-benzoate. Ntunde et al. (1977) also reported no significant alterations in lean texture, colour or firmness due to zeranol treatment, whilst Nute & Dransfield (1984) found that there were no significant changes in colour of lean and fat, apparent fat:lean ratio, lightness, saturation or hue angle.

Lawrie (1960) reported that although meat from hexoestrol-treated steers appeared somewhat redder due to the lower levels of intramuscular fat, there was no evidence of the sticky, purplish condition characteristic of dark cutting meat; neither was there any indication of an increase in ultimate pH or in myoglobin concentration.

Bulls Chemical analyses by various workers showed that no significant change in ~o ether extractable fat or ~o moisture (Garrigus et al., 1969: Williams et al., 1975a: Martin & Stob, 1978), ~o protein (Williams et al., 1975a: Martin & Stob, 1978) or ash levels (Williams et al., 1975a) had occurred in meat from diethylstilboestrol-treated bulls. Garrigus et al. (1969) found that implantation at 154 days post-weaning significantly (P< 0-01) reduced the U,, protein in meat but that diethylstilboestrol treatments at other ages gave no significant alteration. The wflues for ether extractable material obtained by Williams et al. (1975a), although not significantly altered by treatment, were slightly increased over controls. Wierbicki et al. (1956) noted that diethyistilboestrol administration gave a small increase in intramuscular fat while "//o moisture and ~. o nitrogen showed little change. They also reported that hydroxyproline levels were higher in meat from treated bulls, while the pH at 3 and 13 days post mortem was virtually unchanged.

Gregory et al. (1983) discovered that zeranol treatment had no significant effect on ~ water or protein in the M. Iongissimus dorsi. However, the % fat in the muscle from bulls treated with 36 mg zeranol on two occasions was significantly (P < 0-05) increased compared with controls, while the '~,] fat for bulls treated initially with 72 nag zeranol lay between the other two classes. Greathouse et al. (1983) reported that repeated zeranol implantation of bulls tended (P = 0"06) to give higher ';0 ether extractable material and lower "/moisture in the 9th- 10th- 11 th rib /o section, while ~,i protein was not significantly altered. Forrest (1975) also


reported a significant increase in ether extractable fat in the M. longissimus dorsi of bulls treated with progesterone + oestradiol-17/l- benzoate.

Thus, bulls treated with oestrogenic compounds show a tendency towards higher levels of ether extractable fat although, in many cases, no significant effects were observed. This trend was also reported by Galbraith & Topps (1981) in their review.

The marbling score for meat from diethylstilboestrol-treated bulls has been shown not to differ significantly from that for untreated animals (Garrigus et al., 1969: Williams et al., 1975a,b), although it was slightly increased in some cases. Several studies suggested that bulls treated with zeranol showed no change in the scores for marbling (Gregory & Ford, 1983; Gregory et al., 1983; Ford & Gregory, 1983; Greathouse et al., 1983; Johnson et al., 1984), texture (Gregory & Ford, 1983: Ford & Gregory, 1983), firmness (Greathouse et al., 1983) or colour (Gregory & Ford, 1983: Ford & Gregory, 1983: Greathouse et al., 1983) of the lean compared with controls. However, McKenzie (1983) considered that bulls implanted with zeranol produced lighter coloured flesh while Greathouse et al. (1983) reported that the texture of meat from implanted bulls was significantly (P < 0"05) less fine than that of controls. Johnson et al. (1984) also found that treatment of bulls with oestradiol-17fl or progesterone+oestradiol-17/~-benzoate had no efl'ect on marbling scores .

Veal cah'es Grandadam et al. (1975) analysed the M. psoas major ot" veal calves for total nitrogen and lipids and found that treatment with trenbolone acetate + oestradiol-17B caused no significant changes. Verbeke et al. (1975) found that, although a similar treatment had no significant effect on ~/0 moisture, protein or ash content ol the defatted 3rd rib cut. it did cause a reduction in 3~,; fat and an increase in 3',, collagen (P < 0-05, paired values). None of these parameters was significantly affected by testosterone + oestradiol-17fl.

Neither author found any significant alteration in meat coloration due to this hormone treatment, although the former reported that thc meat from half of the treated calves was judged as "white" (rather than pink or red) compared with only 40 '},, from the controls. There was no significant change in the water-holding capacity of the raw meat (Verbeke et al., 1975).


Heifers and cows Two independent studies (Marchello et al., 1970; Price & Makarechian, 1982) reported that none of several treatments applied to heifers and cows had any significant effect on the marbling score given to the meat.

Pigs

Various workers investigated the chemical composition of pork following hormone treatment. Bidner et al. (1972a) reported that hams from diethylstilboestrol + methyltestosterone-treated barrows and gilts collec- tively contained significantly (P < 0.01) more moisture and protein, and less fat, than those from controls. However, the increase in ~ protein and moisture was proportional and could be explained purely by the decrease in fat. Both Bidner et al. (1972b) and Plimpton & Teague (1972) indicated that there was no significant difference in 'Uo moisture and fat but Bidner et al. (1972b) found a significant (P < 0-05) decrease in ~ protein in the Iongissimus muscle for both barrows and gilts in one of two experiments; the other showed a non-significant increase in ~o protein and they concluded that there was no significant effect on the gross composition of the muscle. The same authors also studied the proportions of red, white and intermediate types of muscle fibres in treated and untreated pigs, and investigated the fractionation of the muscle proteins into sarcoplasmic, myofibrillar, non-protein and stroma nitrogen: no significant differences were observed.

Plimpton & Teague (1972) noted that diethylstilboestrol implantation in boars caused a non-significant increase in water content and no significant change in ether extractable material, ~o protein or pH, at 24 h post mortem, of the muscle of the 1 lth-13th rib section of the loin. The amounts of saturated and unsaturated fatty acids in the subcutaneous fat of the 10th-13th rib section were also unaffected by such treatment.

Nitrogen and energy balance experiments were performed on castrate male pigs (van Weerden & Grandadam, 1975). Implantation with oestradiol-17fl + trenbolone acetate consistently gave significant increases in nitrogen retention, which peaked at about 9-14 days after implantation and decreased to control levels after 5-6 weeks. However, energy retention was unaltered (at 13-17 days after treatment), indicating that the increase in protein deposition was accompanied by a decrease in fat deposition.

Bidner el al. (1972b) and Lucas et al. (1971) reported that treatment of


barrows and gilts with diethylstilboestrol + methyltestosterone did not cause a significant change in the degree of marbling in the M. longissimus dorsi and loin eye, respectively. Bidner et al. (1972b) also found no significant differences in the scores for colour, firmness, wateriness and ~total quality' between treated and control meat. Plimpton & Teague (1972) reported that diethylstilboestrol treatment of boars caused no significant alteration in marbling, colour or firmness of the 1 lth-13th rib chops. Similar results were obtained by Ockerman et al. (1981).

Sheep

The effects of hormone treatment on meat composition were reasonably consistent. Sharp & Dyer (1971) implanted wether lambs with zeranoi and reported a significant (P < 0.05) decrease in % ether extract and an increase in % protein in the meat compared with controls, as determined by specific gravity measurements. The 0/o water also increased (but not significantly), and they proposed that the increase in protein content occurred at the expense of fat. They reported that there was a significant increase (P < 0.05) in nitrogen retention, but that energy retention fell due to the decrease in fat deposition. The latter effect, however, was not significant due to the high variation in carcass tat content. Muir et al. (1983) reported that the oral administration of diethylstilboestrol to wether lambs significantly increased the quantity of protein (P < 0"01) and moisture (P < 0-05) in the carcass but only caused a small, non- significant, decrease in the carcass fat. Galbraith et al. (1980) used combinations of trenbolone acetate+oestradiol-17B and trenboione acetate + zeranol in wether lambs; all treatments increased the total water and crude protein content of the carcass. The former combination, when implanted in lambs weighing about 28 kg, gave the most significant (P < 0.01) alterations, while the use of both treatments in heavier lambs (40 kg) resulted in smaller changes, which failed to reach significance for trenbolone acetate + zeranol. However, the fat/protein ratio was reduced significantly (P < 0-05) by all treatments. These results are in agreement with those cited by Galbraith & Topps (1981) in their review in which diethylstilboestrol, hexoestrol, zeranol and trenbolone acetate + oestradiol- 17/3 were reported to increase the levels of protein and water, and to reduce fat in wether lambs.

Treatment with zeranol had no effect on the marbling, texture, firmness or colour scores for meat from rams, wethers and ewes, according to


Wilson et al. (1972) and Wiggins et al. (1976): marbling scores were also unaltered for cryptorchid lambs (Wilson et al.. 1972). Diethylstilboestrol treatment, however, gave meat with increased marbling and firmness scores and, whilst these effects were not significant, the combination of diethylstilboestrol + zeranol gave a highly significant rise (P < 0.01) in the score for firmness (Wiggins et al., 1976). In separate work, Purchas (1973) noted that the pH of the M. longissimus dorsi was unaltered by treatment with melengesteroi acetate.

Poultry

York & Mitchell (1969) compared cockerels treated with oestradiol-17fl- monopalmitate with both untreated birds and capons, and studied the composition of the individual muscles and organs, rather than that of the whole carcass. They found that there was significantly (P < 0.05) greater '~ fat in the M. pectoralis major and liver of treated birds than in the controls, while fat in the composite thigh muscles was also increased, although not significantly. For all three tissues the ~,~ moisture was significantly (P


study of the eating quality characteristics, have reported data on tenderness obtained by one or other of these methods, These reports have been grouped together under a separate heading for convenience.

Tenderness Borger et al. (1973a), Ntunde et al. (1977) and Nute & Dransfield (1984) found that treatment of steers with zeranol had no significant effect on taste panel scores for tenderness. Ntunde et al. (1977) also determined tenderness instrumentally using the Warner-Bratzler shear test, while Nute & Dransfield (1984) used Volodkevich jaws on an Instron materials testing machine; neither found a difference due to zeranol treatment.

The effect of hexoestroi implantation on steers has been investigated by Preston et al. (1961), Bryce-Jones et al. (1964) and Hill (1966). No significant differences were found in the Warner-Bratzler shear values (Hill, 1966) nor in taste panel toughness scores (Preston et al., 1961). In one of two experiments, Bryce-Jones et al. (1964) found that the tenderness of the roasted meat was significantly (P < 0-01) higher for treated steers, whilst, in the other, the effect was not significant. However, the tenderness of the stewed meat was found to be non-significantly lower.

The posterior top round roast from diethylstilboestrol-treated steers was judged significantly less tender (P < 0.05) by taste panelists while the other cuts showed the same trend but did not differ significantly from controls (Simone et al., 1958). Wierbicki et al. (1956) also found that diethylstilboestrol treatment gave slightly tougher meat for bulls and steers, and Forrest & Sather (1965) reported that treatment of steers with diethylstilboestrol or progesterone + oestradiol-17/J-benzoate produced significantly (P < 0.05) less tender meat than controls. In contrast, later work showed no significant difference in taste panel scores for tenderness attributable to treatment with progesterone + oestradiol-17,B-benzoate in bulls or steers (Forrest, 1975). Williams et al. (1975a) reported that diethylstilboestrol implantation in bulls had no effect on tenderness. However, a later paper reported lower scores for palatability traits, including tenderness, but the reductions were not significant (Williams et al., 1975b). Galbraith & Topps (1981) concluded that diethylstilboestroi may slightly reduce tenderness in both bulls and steers. Zeranoi treatment of bulls caused no significant effect on tenderness, either when determined as the Warner-Bratzler shear force or when judged by a sensory panel, although there was some tendency towards increased shear force and decreased tenderness score with treatment (Gregory et al., 1983).


Greathouse et al. (1983) investigated the effect of repeated treatment of bulls with zeranol on the Warner-Bratzler shear force, the taste panel scores for myofibrillar tenderness and overall tenderness of M. longissimus dorsi steaks. Although any changes were not always statistically significant, tenderness scores were consistently improved and taste panel evaluation of the amount of connective tissue in the meat showed a significant (P < 0.05) reduction. Meat from bulls treated with zeranol, oestradiol-1713 or progesterone + oestradiol-17/~-benzoate was assessed for muscle fibre tenderness, connective tissue amount, overall tenderness and shear force; no significant effects were observed (Johnson et al., 1984).

Veal calves, implanted on two occasions with testosterone + oestradiol- 1713, showed significantly (P < 0-05) increased Warner-Bratzler shear values for the M. longissimus dorsi; other treatments, including those using trenbolone acetate + oestradiol-1713, gave non-significant effects in the same direction (Verbeke et al., 1975).

Thus, there may be some tendency for oestrogen treatment of bulls and steers to yield slightly tougher meat. However, the results are by no means consistent; many studies showed no significant effect whilst others indicated that tenderness was actually improved.

It is worth commenting, perhaps, that studies on the organoleptic properties of meat involve the use of standard cooking techniques and trained taste panelists; such methods will be more discriminating than is the average consumer when judging meat as part of a meal (Dransfield, 1984).

Juichwss, f lavour, colour and overall acceptability Several authors (Borger et al., 1973a; Ntunde et al., 1977; Nute & Dransfield, 1984) have reported that zeranol implantation has no significant effect on the flavour or juiciness of the meat from treated steers and that the overall acceptability is unchanged (Borger et al., 1973a; Ntunde et al., 1977). Borger et al. (1973a) noted a correlation between the taste panel scores for acceptability for the M. longissirnus dorsi and either the final grade of the carcass or the % fat level, whilst Nute & Dransfield (1984) recorded the lightness, hue angle and saturation, as well as subjective scores for the colour and colour intensity of the cooked meat, and found no significant differences.

Preston et al. (1961) reported that treatment of steers with hexoestrol had no significant effect on the juiciness, flavour, palatability or the


occurrence of rancidity in the meat. On the other hand, Bryce-Jones et al. (1964) reported that the flavour of roasted meat from treated steers was significantly (P < 0.05) better than controls in one experiment, whilst, in another, the increase was not significant. There was no significant effect on juiciness. For the stewed meat, however, the flavour of both the meat and the liquor was significantly poorer (P < 0-05 and 0-01, respectively) than for the control meat.

Simone et al. (1958) and Williams et al. (1975a,b) both recorded non- significant differences in flavour and juiciness for roast meat from diethyistilboestrol-treated steers and bulls, although the treated meat was scored slightly less in some cases. The method of diethylstilboestrol administration (orally or by implantation) did not affect the juiciness, flavour or tenderness (Simone et al., 1958). Some correlation was noted between juiciness and moisture content (P < 0.05) but more between juiciness and the ether extract of the rib eye muscle (P < 0.01) (Simone et aL, 1958). Forrest & Sather (1965) implanted steers with diethylstilboestrol or progesterone + oestradiol-17~-benzoate and found that treatment tended to reduce the scores for juiciness and flavour of the lean and fat--significantly so (P < 0.05) for some weight groups. The overall desirability score for the treated meat was significantly (P < 0-05) lower than for control meat in all cases. However, a later study involving the administration of progesterone + oestradiol-17]~-benzoate to steers and bulls did not alter the scores for juiciness, flavour of lean or fat, or the overall score for the meat, although there was a sex x treatment interaction which indicated that juiciness was reduced for steers, but increased for bulls, as was the fat content of the M. longissimus dorsi (Forrest, ! 975).

Scott (1978), in his review, reported that meat from steers treated with trenboione acetate, zeranol or trenbolone acetate + hexoestrol showed no consistent or important differences in eating quality.

The treatment of bulls with 36 mg zeranol at approximately 1 year of age, and again 70 days later, had no significant effect on sensory panel scores for flavour intensity, juiciness, amount of connective tissue or ease of fragmentation (Gregory et al., 1983). Treatment with 2 x 36mg zeranol at 1 year only gave similar results except for flavour, which scored significantly less (P < 0-05) than for control or twice-implanted bulls. In contrast, five successive zeranol implantations in bulls significantly (P < 0.05) increased the taste panel scores for flavour while those for juiciness were not significantly altered (Greathouse et al., 1983). No differences in


juiciness, off-flavour or overall palatability could be detected by taste panels following implantation of bulls with zeranol, oestradioi-17fl or progesterone + oestradiol-17fl-benzoate (Johnson et al., 1984).

Cooking losses Conflicting results have been reported for cooking losses: Nute & Dransfield (1984) reported that zeranol treatment had no effect on cooking losses for meat from steers, while Borger et al. (1973a) recorded significantly (P < 005) greater cooking losses for treated meat which he suggested was due to the greater % moisture present. He also noted more shrinkage of the treated meat during cooking. Bryce-Jones et al. (1964) reported an increase in % drip loss during cooking which was just significant at the P


that, although diethylstilboestrol has been shown to suppress boar odour (Plimpton & Teague, 1972; Ockerman et al., 1981)~ the amount administered in this case was inadequate to achieve this. However, in the remaining experiment of this series, Lucas et al. (1971) found no response to hormone supplementation when using barrows of an 'extremely lean, meaty type': no significant changes in the incidence of undesirable odours or flavours were noted. Plimpton & Teague (1972) also reported an increase (P < 0.05) in boar odour of the meat from barrows and gilts following similar treatment. However, in contrast to most of the results of these authors, Bidner et al. (1972a) reported that taste panel overall acceptability scores for loin roasts did not reflect any differences attributable to hormone treatment.

The administration of diethylstilboestrol to boars, either by implantation or by addition to feed, has been shown to suppress significantly (P < 0-05) boar odour in the meat. Increasing doses of implanted diethylstilboestrol (48-144mg) gave a linear decrease in boar odour (Plimpton & Teague, 1972) and Ockerman et al. (1981) found that implantation of 96 mg diethyistilboestrol resulted in heavyweight boars with sensory characteristics intermediate between those of untreated boars and barrows. Although mean androsterone levels were reduced |Yom 1.38 to 0.82/tg/g by implantation, the change was not statistically significant because of high inter-animal variation. Scores for tenderness were not altered.

Sheep

Although wether lambs implanted with hexoestrol showed a highly significant increase in liveweight gain, there were no significant differences between the treated and control sheep with respect to taste panel scores for juiciness, toughness, ftavour or palatability of the leg joints (Preston et al., 1961). Some taints were recorded but these were not associated with any one treatment. Purchas (1973) measured tenderness using a Warner- Bratzler shear device on the cooked meat and found no significant changes attributable to treatment with melengesterol acetate.

Poultry

Oestrogen treatment of chickens appears to have little or no effect on the organoleptic qualities of the meat. Bassila et al. (1975) found no

214 R. L. S. Patterson, Linda J. Saltt'r

significant change due to treatment with oestradiol-17/~-monopaimitate or dienoestrol diacetate in the taste panel scores for the flavour, odour or texture of breast or thigh meat, or in the texture values obtained using a Kramer shear press. York & Mitchell (1969) compared the scores for tenderness, flavour, juiciness and overall preference for meat from cockerels treated with oestradiol-17B-monopalmitate, control cockerels and capons. Although no significant differences were found between any of the three groups, the hormone-treated birds and the capons tended to receive higher scores than controls for all these factors.

No significant change in ~ cooking loss was observed following the injection of chickens with oestradiol-17/~-monopaimitate (York & Mitchell, 1969; Bassila et al., 1975), or the oral administration of dienoestrol diacetate (Bassila et al., 1975); ~ thawing loss and cooking time were also found to be unaltered (York & Mitchell, 1969). Implantation of turkeys with oestradiol-17l~-monopaimitate (Moran & Etches, 1983) caused no significant change in ~ cooking loss.

DISCUSSION

The number of growth-promoting substances permitted at present by law for general use in fattening farm animals is less than a decade ago; those currently allowed by the EEC are based upon the naturally occurring hormones and two xenobiotics (trenbolone acetate and zeranol), although the EEC intends to impose a ban on these latter two in the near future. Thyrostatics and the purely synthetic stilbene-based agents (hexoestrol, diethylstilboestrol) are banned for this purpose in the EEC countries.

Steers respond to both androgenic and oestrogenic substances, as they are deficient in endogenous hormones. The level of lean in a carcass is usually increased while the fat content decreases after application of either a single or combination hormone treatment, although the changes may not always be statistically significant. Changes in the chemical composition of the musculature are reflected in decreased fat percentage accompanied by increased ~ protein and, in most cases, ~ water. In some cases, the ratio of water to protein is almost unchanged, indicating that the increases may be attributed simply to the decrease in fat percentage. Since normal muscle usually contains about 75 ~ water, any treatment which reduces the proportions of fat in a sample joint will appear to have increased the water content. No consistent changes for


collagen content have been noted. Zeranol treatment of steers has no significant effect on the subjective marbling scores nor on the apparent lean-fat ratio. No significant changes were noted in the colour of the fat or lean, nor in the lightness, saturation or hue angle. Losses during cooking, however, differed between experiments. Conflicting results have also been noted for marbling fat scores and cooking drip loss following treatment with other oestrogenic preparations. The eating quality attributes (tenderness, juiciness, flavour, colour and overall acceptability) of meat from zeranol-treated steers are not significantly altered. Hexoestrol treatment seemed to improve tenderness but gave conflicting results for flavour, depending on the cooking method. However, several workers noted small, occasionally significant, reductions in tenderness following treatment with diethylstilboestrol or progesterone + oestradiol- 17/~-benzoate; flavour was unaltered but the latter preparation gave slightly less juicy meat than controls.

Bulls treated with oestrogenic compounds tend to deposit more fat and also show some tendency towards higher levels of ether extractable fat and lower levels of protein (and sometimes water) in meat joints, although these latter effects are not statistically significant in many cases. There is some evidence for changes in collagen levels and bone growth but the direction of the latter is variable. Oestrogen treatment of bulls has not been found to cause significant changes in marbling scores for the lean although non-significant increases have been noted in some cases. Zeranol, in particular, does not change marbling, texture, firmness or colour of lean, or alter cooking losses. The palatability traits are largely unaffected by any of the treatments. While tenderness may-be-slightly reduced by diethylstilboestrol, bulls treated with zeranol showed some tendency to give more tender meat with less connective tissue. One report observed some evidence of increased juiciness in oestrogen-treated bulls, possibly due to increased fat deposition. A significant increase in flavour was recorded for meat from bulls after five successive implantations of zeranol, but there was no concomitant change in juiciness scores.

Heifers and con,s tend to respond to preparations containing androgen and show increased muscle development, usually without change in fat deposition. Marbling scores, drip losses and other muscle quality attributes remain unaffected by most treatments.

Treatment of veal calves with the combined preparation, trenbolone acetate + oestradiol-17/~, shows a slight tendency to increase the proportion of lean meat and to reduce ~o fat in the 3rd rib. Muscle analysis

216 R. L. S. Patterson. Lin&t J. Salter

showed no alteration in /o protein, moisture or ash but % fat was reduced and o/,o collagen increased. Treatment with testosterone + oestradiol-17/3 has little effect on these parameters. Tenderness may be slightly decreased by both hormone treatments. However, meat coloration, water-holding capacity and cooking losses from pieces of meat were unaltered, although cooking losses from minced meat were slightly increased.

Oral treatment of gilt and castrate (barrow) pigs with combined androgen + oestrogen preparations (e.g. diethylstilboestrol + methyltestosterone) nearly always results in some reduction in backfat thickness (often reaching statistical significance) accompanied by small, sometimes significant, increases in muscle area and ~o lean cuts; the magnitude of these effects is generally greater in castrates. Some workers have reported proportional increases in protein and moisture which can be related to an accompanying reduction in fat, whilst others have concluded that this treatment has no significant effect on the gross composition of the muscle. Scores for degree of marbling and for other raw meat quality attributes are unaffected. In boars, diethylstilboestrol implantation tends to increase backfat thickness, without change in fatty acid composition, and without si~,nificant~ alteration in longissimus muscle area, "/,, o protein, ether extractable fat, water content or pH at 24h post mortem. Whilst this treatment of boars has been shown to suppress significantly the development of boar odour in the meat. an increased incidence of boar odour in gilts and barrows has been noted in several experiments in which diethylstilboestrol was applied in combination with methyltestosterone: this curious finding was explained by assuming that insufficient oestrogen was present to suppress formation of the taint substance (5~- androstenone) promoted by the administered androgen. Other re- searchers, however, have found no differences in taste panel scores for meat from similarly treated animals.

Zeranol implantation of sheep had no significant effect upon the gross carcass composition of rams, wethers or ewes. However, percentage protein in the meat increased whilst ~o ether extractable matter decreased: there was no effect on scores for raw meat quality. Oral administration of diethylstilboestrol increased protein (and moisture) in wether lambs, with only a small, non-significant, decrease in carcass tat, whilst implantation of the same oestrogen, either alone or with zeranol, significantly increased fat cover but had no significant effect on muscle area or "/kidney fat: whether fat deposition is increased or decreased as a / O result of diethylstilboestrol treatment may depend upon the


calorie:protein ratio of the diet. Small, non-significant, increases in scores for marbling and firmness were noted. Hexoestrol implantation gave significant increases in liveweight gain. without detriment to taste panel scores for flavour.juiciness, toughness or palatability. Ewes responded to trenbolone acetate implantation by increasing significantly deposition of lean tissue and carcass fat. A combination of trenbolone acetate with either oestradiol-17/~ or zeranol resulted in increased total protein in wether lambs, the greatest effect being obtained with early implantation: the fat:protein ratio was reduced significantly by both treatments.

Treatment ofpottltry (cockerels) with oestrogenic compounds resulted in increased deposition of fat and often significant changes in both the absolute and relative weights of body components and organs. However, no significant difference in )~o fat was observed between oestrogen-treated cockerels and capons. Reduced values for percentage protein, moisture and ash have also been recorded by some workers, but were probably caused by the increased fat levels. Turkey toms similarly implanted showed increased fat content and improved fleshing. Percentage thawing loss and '!Jo cooking loss appeared to be unaffected by treatment, as were the organoleptic qualities: taste panel scores for flavour, odour and texture of breast and leg meat were not significantly altered, although meat from capons and hormone-treated cockerels tended to receive higher scores.

CONCLUSION

Overall, it appears that the major effects arising from the use of anabolic agents in meat production are manifest primarily in the well-known improvements in growth performance--not discussed in this review, but well documented elsewhere (Scott, 1978: Galbraith & Topps, 198 l)--with lesser effects being apparent in the carcass composition. For example, hormone treatment of castrate male and female animals tends to increase the proportion of lean meat and to decrease that of fat, while entire males show increased fat deposition. These changes may then be reflected in the chemical composition of the muscle: for example, the higher percentages of protein and moisture found in meat from treated steers. However, few workers noted any consistently significant effects on the eating quality of the cooked material as the changes often varied in direction between experiments. Thus, it appears that the use of anabolic agents exerts only

218 R. L. S. Patwrson. Linda J. Salter

minor effects on the basic eating quality parameters of beef, pork, lamb and poultry meats, as appreciated by the consumer.

REFERENCES

Akiba, Y., Jensen, L. S. & Lilburn, M. S. (1982). J. Nutr., 112, 189. Akiba, Y., Takahashi, K., Kimura. M., Hirama, S.-[. & Matsumoto, T. (1983).

Br. Poult. Sci., 24, 71. Bassila, M. K., Adams, R. L., Pratt, D. E. & Stadelman, W. J. (1975). Poult.

Sci., 54, 696. Bidner, T.D., Merkel, R. A,, Miller, E.R., Ullrey, D.E. & Hoefer, J.A.

(1972a). J. Anita. Sci., 34, 397. Bidner, T. D., Merkel, R. A. & Miller, E. R. (1972b). J. Anita. Sci., 35, 525. Bogdonoff, P. D., Henson, J. N. & Thrasher. G, W. (1961). Poult. Sci., 40, 1637. Borger, M. L., Wilson, L. L., Sink, J, D., Ziegler, J. H. & Davis, S. L. (1973a). J.

Anita. Sci., 36, 706. Borger, M. L., Sink, J. D., Wilson, L. L., Ziegler, J. H. & Davis, S. L. (1973b). J.

Anita. Sci., 36, 712. Bryce-Jones, K,, Harries, J. M. & Houston, T. W. (1964). J. Sci. Fd. Agric., 15,

62. Cohen, R. D. H. & Cooper, J, A. (1983). Can. J, Anita. Sci., 63, 361. Donovan, G. A. & Sherman, W. C. (1960). Poult. Sci., 39, 757. Dransfield, E. (1984). Proc. 8th Assoc. Vet. Clin. Pharmacol. and Therapeutics,

56. Ford. J. J. & Gregory, K. E. (1983). J. Anita. Sci., 57, 286. Forrest, R. J. (1975). Can. J. Anita. Sci., 55, 287. Forrest, R. J. & Sather, L. A. (1965). Can. J. Anita. Sci., 45, 173. Fowler, V. R. (1975). Proc. ConJ~ "Anabolic Agents in Animal Production" (Lu,

F. C. & Rendel, J. (Eds)), Georg Thieme, Stuttgart, 109. Galbraith, H. & Topps, J, H. (1981). Nutr. Abstr. Rev. Ser. B, 51,521. Galbraith, H., Topps, J. H,, Coelho, J. F. S. & Yasin, A. R. M. (1980). Proc. 3rd

Eur. Assn Anita. Prod. Syrup. Prot, Metab. Nutr, (Oslage, H. J. & Rohr, K. (Eds)), 509.

Garrigus, R. R., Martin, T. G., Stob, M. & Perks, D. R. (1969). J. Anita. Sci., 29, 75.

Gielen, M., Bienfait, J. M., Lambot, O., Van Eenaeme, C. & Istasse, L. (1982). Annls. reed. vet., 126, 133.

Goodman, J. P., Slyter, A. L. & Embry, L. B. (1982). J. Anita. Sci., 54, 491. Grandadam, J. A., Scheid, J. P., Jobard, A., Dreux, H. & Boisson, J. M. (1975).

J. Anita. Sci., 41,969. Greathouse, J. R., Hunt, M. C., Dikeman. M. E., Corah, L. R., Kastner, C. L.

& Kropf, D. H. (1983). J. Anita. Sci., 57. 355. Gregory, K. E. & Ford, J. J. (1983). J. Anita. Sci., 56, 771. Gregory, K. E., Siedeman, S. C. & Ford, J. J. (1983). J. Anita. Sci., 56, 781. Grilfiths, T. W. (1982). Anita. Prod., 34, 309.


Hill, F. (1966). J. agric. Fd. Chem., 14, 179. Johnson, D.D., Savell, J.W., Smith, G.C., Gill, D.R., Williams, D.E.,

Walters, L. E. & Martin, J. J. (1984). J. Anim. Sci., 58, 920. Jones, S. D. M. (1982). Can. J. Anim. Sci., 62, 295. Lambot, O., Van Eenaeme, C., Gielen, M. & Bienfait, J. M. (1983). Rew~e

Agric., Brux., 36, 5. Lawrie, R. A. (1960). Brit. J. Nutr., 14, 255. Lucas, E. W., Wallace, H. D., Palmer, A,-Z. & Combs, G. E. (1971). J. Anim.

Sci., 33, 780. Marchello. J. A., Ray, D. E, & Hale, W. H. (1970). J. Anim. Sci., 31, 690, Martin, T. G. & Stob, M. (1978). J. Dairy Sci., 61, 132. Mathison, G. W. & Stobbs, L. A. (1983). Can. J. Anim. Sci., 63, 75. McKenzie, J. R. (1983). N.Z. vet. J., 31, 104. Moran, Jr., E. T. & Etches, R. J. (1983). Poult. Sci., 62, 1010. Muir, L. A., Wien, S., Duquette, P. F., Rickes, E. L. & Cordes, E. H. (1983). J.

Anita. Sci., 56, 1315. Nesheim, M. C. (1975). Proc. ConJ~ 'A nabolic Agents in Animal Production" (Lu,

F. C. & Rendel, J. (Eds)), Georg Thieme, Stuttgart, 110. Ntunde, B. N., Usborne, W. R. & Ashton, G. C. (1977). Can. J. Anita. Sci., 57,

449. Nute, G. R. & Dransfield, E. (1984). J. Fd. Technol,, 19, 2l. Ockerman, H. W., Plimpton, Jr., R. F. & Patterson, R. L. S. (1981). J. Food

Sci., 46, 1144. Ogilvie, M. L., Faltin, E. C., Hauser, E. R., Bray, R, W. & Hoekstra, W. G.

(1960). J. Anita. Sei., 19, 991. Plimpton. Jr,, R. F. & Teague, H. S. (1972). J. Anita. Sei., 35, 1166. Preston, T.R., Greenhalgh, I., Boyne, A.A., Crichton, J.A., Rolfe, E.J..

Brown, A. & Dodsworth, T. L. (1961). Anim. Prod.. 3, 233. Price, M. A. & Makarechian, M. (1982). Can. J. Anim. Sci., 62, 739. Price, M. A., Makarechian, M., Tennessen, T. & Mathison, G. W. (1983). Can.

J. Anita. Sci., 63, 803. Prior, R. L., Crouse, J. D., Harrison, V. I, & Baile, C. A. (1978). J. Anim. Sei.,

47, 1225, Purchas, R. W. (1973). Aust. J. agric. Res., 24, 927. Roche, J. F. (1980). Proc. Conj] "The Use, Residues and Toxicology of Growth

Promoters'. An Foras Taluntais, Dublin, 1, Rumsey, T. S. (1982). J. Anita. Sei., 54, 1030. Ryley, J. W., Moir, K. W., Pepper, P. M. & Burton, H. W. (1970). Br. Poult.

Sei., 11, 83. Schanbacher, B, D., Prior, R. L. & Smith, S. B. (1983). Anim. Prod., 37, 73. Scott, B. (1978). ADAS Quarterly Review (MAFF). HMSO, London, 31, 185. Sharp, G. D. & Dyer, !. A. (1971). J. Anita. Sei., 33, 865. Simone, M., Clegg, M. T. & Carroll, F. (1958). J. Anita. Sci., 17, 834. Storie-Pugh, P. (1984). Vet. Practice, 16(19), 4. Sulieman, A. H., Galbraith, H. & Topps, J. H. (1983). Proc. Nutr. Soc.,

56A.


Utley, P. R, Murphy, C. N., Merchant, C. E. & McCormick, W. C. (1980). J. Anim. Sci.. 50, 221.

van Weerden, E. J. & Grandadam. J. A. (1975). Proc. ConJ] ~Anabolic Agents in Animal Production" (Lu, F. C. & Rendel, J. (Eds)), Georg Thieme, Stuttgart, 115.

Verbeke, R., Debackere. M., Hicquet, R., kauwers, H., Pottie, G., Stevens, J., Van Moer, D., Van Hoof, J. & Vermeersch, G. (1975). Proc. ConJ~ "Anabolic Agents in Animal Production" (ku, F.C. & Rendel, J. (Eds)), Georg Thieme, Stuttgart, 123.

Wierbicki, E., Kunkle, k. E., Cahill. V. R. & Deatherage, F. E. (1956). Food Technol., 10, 80.

Wiggins, J. P., Wilson, I,,, k., Rothenbacher, H. & Davis, S. L. (1976). J. Anim. Sci., 43, 518.

Wiggins, J. P., Rothenbacher, H., Wilson, L. L., Martin, R. J., Wangsness, P. J. & Ziegler, J. H. (1979). J. Anita. Sci., 49, 291.

Williams, D. B., Vetter, R. L., Burroughs, W. & Topel, D. G, (1975a). J. Anita, Sci., 41, 1525.

Williams, D. B., Vetter. R. L., Burroughs, W. & Topel, D. G. (1975b). J. Anita, Sci., 41, 1532.

Wilson, L. L., Varela-Alcvarez, H.. Rugh, M.C. & Borger, M. L. (1972). J, Anita. Sci., 34, 336.

Wood, J. D. & Fisher, A. V. (1983). Proc. 34th Annual Meeting of the European Association for Animal Production (EAAP), Commission opt Cattle Pro~htction, Madrid, 500.

York, L. R. & Mitchell, J. D. (1969). Poult. Sci., 48, 1532.

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Anabolic Agents and Meat Quality Patterson1985