J. Vet. Med. B 40,667-675 (1993) 0 1993 Paul Parey Scientific Publishers, Berlin and Hamburg ISSN 093 1 - 1793

Department of Forensic Veterinary Medicine and Veterinary Medicine Administration, Chair of Bird Diseases, University of Agriculture and Technology, Olsztyn,

Chair of Physiology, University of Agriculture, Warsaw, Poland

Effects of Concurrent Oral Administration of Monensin and Selenium on Some Haematological and Biochemical

Parameters in Broiler Chickens

M. 2. KHAN'", J. SZAREK':'':', M. SAEED', A. KONCICKP, and A. KRASNODEBSKA-DEPTA~

Address of authors: 'Department of Forensic Veterinary Medicine and Veterinary Medicine Ad- ministration, ul. Oczapowskiego 13, University of Agriculture and Technology, 10-717 Olsztyn, Poland; %hair of Physiology, University of Agriculture, 02-766 Warsaw, Poland; 'Chair of Bird Diseases (seel); ';Current address: Department of Veterinary Pathology, University of Agricul-

ture, Faisalabad, Pakistan; 'w Reprint requests address

With 9 tables

(Received for publicationJuly 7, 1993)

Summary Monensin and selenium (sodium selenite) at different toxic levels were administered orally to

the broiler chickens for variable periods. A depression in haematological parameters and biochemi- cal ones such as alanine and aspertate aminotransferase, serum total protein and cholesterol were recorded in acute and subacute toxicosis of these substances. The present experiments led to the conclusion that concurrent administration of selenium and monensin at toxic levels resulted in exas- perated toxic response in broiler chickens which in turn had been produced by embellishment of toxicosis inducing properties of both examined substances.

Introduction Monensin is an ionophore anticoccidial agent commonly used in poultry. It is high-

ly effective against all species of coccidia in field and has additional growth-promoting properties. It has shown however intermittent toxicity to numerous animals and may be fatal when used at higher doses than recommended (2,7,9, 12).

The provision of adequate levels of selenium and/or vitamin E plays an important role in animal management, especially in intensive feeding or fattening. Its daily intake depends partly on the composition of the feed; the more unsaturated fatty acids are being given, the more selenium is needed. Selenium alone is known to produce acute or chro- nic toxicoses.

The experiment was performed in the framework of research project 4.100.201.

U.S. Copyright Clearance Center Code Statement: 093 1 - 1793/93/4009 - 0667$02.50/0

668 KHAN, SZAREK, SAEED, KONCICKI, KRASNOD~BSKA-DEPTA

Administration of selenium at therapeutic levels either prior to or during monensin toxicosis has resulted in a partial protection and amelioration of the signs relative to toxic effects of the anticoccidial d rug (16 - 18). On the other hand, administration of safe doses of monensin to lambs previously intoxicated with selenium has aggravated the toxic reaction as quoted by increased mortality in the flock and elevated selenium contents in various body tissues (I I). Up to the date, very limited number of reports have been given on variations of toxic effects resulting from simultaneous administration of selenium and monensin. The series of experiments was carried ou t on broilers to corroborate the character of alterations in heamatological and biochemical parameters due to concurrent administration of selenium and monensin at different toxic doses and for changing duration.

Material and Methods Experiment 1

Broiler chickens (Astra B breed) were continuously fed with basal feed (BK-2 broiler grower mash). After two weeks the birds were divided into nine experimental groups, and a first toxic sub- stance was administered in the feed als follows: groups B O and BM were given feed with addition of selenium plus vitamin E (15 mg. and 200 mg. per kg. body mass, respectively) as sodium selenite and alpha tocopherol, whereas groups C O and CS were kept on feed with addition of monensin (240 mg. per kg. body mass) as monensin sodium (Elanco Laboratories, Italy). Three other groups, that is ES, EM and EO, were given basal feed free of additions of toxic substances. The second toxic substance was administered after allowing 12 days of adaptation period in order to induce an acute toxic reaction. Selenium (8 mg. per kg. body mass) was administered orally as a single toxic dose to the birds in groups CS and ES. In the same manner monensin (400 mg. per kg. body mass) was administered to the birds from groups AM, BM and EM. In this way, the birds in groups AM, BM and CS were concurrently given selenium and monensin at different proportions.

Experimental groups AO, BO and ES received only selenium whereas the groups C O an EM were given monensin at different proportions and for various periods of time. Finally, the birds in group E O were kept as untoxicated controls. A more detailed schedule of the experiment has been presented in Table 1.

Three birds from each group were sacrificed at 24 hours post intoxication (p. i.) to collect blood and visceral organs for further pathological studies. Remaining birds were being observed for up to two weeks afterwards. These were also killed, blood and internal organs were collected.

Experiment 2 Concerning the second experiment, formation of particular groups of birds as well as admini-

stration of the first toxic substance remained unchanged in comparison to Experiment 1. Certain differences including the number of experimental animals, length of adaptation period, etc. are given below (Table 1). The second toxic substance was administrered to different groups of birds on alter- nate days for four weeks at following doses: selenium - 1 mg. and monensin - 40 mg. per kg. body mass. Three birds from each group were sacrificed on lst, 2nd, and 4th week p. i. for subsequent collection of blood and viscera.

Haematology and biochemical methods Erythrocyte and leukocyte counts employing haemocytometer, haemoglobin levels (DRAB-

KIN method) and pocket cell volume (PCV) (microhaematocrit technique) were determined accor- ding to COLES (3). Blood serum was used to measure the levels of alanine aminotransferase (AIAT) and aspartate aminotransferase (AspAT) by REITMAN and FRANKLE method (Lachma, N. P. BRNO Chempol, Czechoslovakia), alkaline phosphatase (AP) as described by BASSEY and LOWERY (Bio- chem POCH, Gliwice, Poland), total protein by biuret technique (Biochem POCH, Gliwice, Poland), and cholesterol with the use of colorimetric method (Biochem POCH, Gliwice, Poland).

Comparative analysis was carried out to evaluate differences between the groups treated with the same chemical as the second toxic substance (lead or selenium) and their counterparts receiving either single or non-toxic dose of substances in the feed. Obtained results were then analysed by the analysis of variance, and mean values of different groups were compared by DUNCAN’S multiple range test at probability level 0.05 (13).

Administration of Monensin and Selenium 669

Table 1. Design of the experiment a. Experiment 1

b. Experiment 2 The principles of the second experimental work remained unchanged as compared to Experiment 1 excluding: 1. each experimental group comprised 15 birds; 2. an adaptation period was extended up to four weeks; 3. the second toxic substance in this experiment was administred orally on alternate days for four weeks after allowing an adaptation period. Dosage selenium - 1 rng. per kg. body mass and monensin - 40 mg. per kg. body mass.

Results Monensin toxicosis

In the first experiment following induced acute toxicosis, the haematocrit levels were elevated, in all the groups as compared with controls, at 25 hours p. i. Haemoglobin levels were also significantly increased in groups BM and EM. At two weeks p. i. haema-

Table 2. Comparison of haematological parameters in different groups of chickens during acute monensin toxicosis (mean * SD)

::. given orally per kg. body mass; ':w selenium + vit. E; PCV packet cell volume; ND not determined; values appearing in the same column with different superscripts are statistically significant (P < 0.05)

670 KHAN, SZAREK, SAEED, KONCICKI, KRASNODEBSKA-DEPTA

Table 3. Comparison of haematological parameters in different groups of chickens during subacute monensin toxicosis (mean + S D )

':- given orally per kg. body mass on alternate days; 'M selenium + vit. E; PCV packet cell volume; values appearing in the same column with different superscripts are statistically significant (P < 0.05)

Table 4. Comparison of biochemical parameters in different groups of chickens during acute monensin toxicosis (mean f SD)

'> given orally per kg. body mass as a single dose; ':M selenium + vit. E; AlAT alanine aminotrans- ferase; AspAT aspartate aminotransferase; AP alkaline phosphatase; values appearing in the samc column with different superscripts are statistically significant (P < 0.05)

Administration of Monensin and Selenium 671

Table 5. Comparison of biochemical parameters in different groups of chickens during subacute monensin toxicosis (mean & SD)

EM. ( - ) I 4O I 5.0k 2.0b 1 465114OC I 37.83: 1.4c I 4.90k1.4d I 28111 13

EO.( - ) I 0 I 2.511.1a I 146M10a I 37.0?2.7bC 12.12M.3a 1259a31

*' given orally per kg. body mass on alternate days; *.': selenium + vit. E; AlAT alanine aminotrans- ferase; AspAT aspartate aminotransferase; AP alkaline phosphatase; values appearing in the same column with different superscripts are statistically significant (P < 0.05)

tological parameters in birds of group BM could not be determined because of the death of all birds by the end of this time. Haematocrit values registered in all other groups were lower than in control group, and in group AM they can be characterized as significantly lower (see Table 2.)

In the second experiment during subacute monensin toxicosis, haematocrit level on 2nd week p. i. was significantly lower in groups AM and BM as compared to all other groups. At four weeks p. i. they still had lower values, and the group AM showed the lowest level. Haemoglobin levels measured in groups AM and BM were significantly lower than those in controls (group EO) at Ist, 2nd, and 4th week p. i. (Table 3).

During acute toxicosis AlAT levels were found elevated in group EM while AspAT and total serum protein levels tended to increase in birds from group EM at 2nd week p. i. Cholesterol levels of all groups except for EM were elevated after two weeks of experi- ment (Table 4).

During the course of subacute toxicosis AspAT levels were significantly higher in groups AM, BO, and EM at 2nd week p. i. and in groups AM, BO, and EM at 4th week p. i. in comparison to respective controls. Total serum protein was found non-signifi- cantly lower in groups AM and BM on 4 weeks p. i. Cholesterol level was elevated in all groups of birds throughout in entire experiment (Table 5 ) .

Selenium toxicosis Apart from elevated levels of haemoglobin observed in groups CO and CS, no sig-

nificant changes were registered in the first experiment aiming to induce acute toxicosis.

672 KHAN, SZAREK, SAEED, KONCICKI, KRASNODEBSKA-DEPTA

Table 6 . Comparison of haematological parameters in different groups of chickens during acute selenium toxicosis (mean f SD)

': given orally per kg. body mass; 'M monensin; PCV packet cell volume; values appearing in the same column with different superscripts are statistically significant (P < 0.05)

At 2nd week p. i. haematocrit level was significantly decreased in all groups, as compared to controls, and groups CO and CS showed the lowest level (Table 6).

During the state of subacute toxicosis all groups showed a significant decrease in PCV values. The lowest level was recorded in group CS, then in ES and CO. Haemoglo- bin level as measured at 4th week p. i. was lowest in groups CS and ES (Table 7).

First experiment revealed a decrease in total protein level in groups CS and ES at 2nd week p. i. Cholesterol level was elevated in all experimental groups of birds (Table 8).

In subacute toxicosis AspAT and cholesterol levels were elevated in all groups at 4th week p. i. Total serum protein was in turn decreased in groups CS and ES in relation to controls (Table 9).

'> given orally per kg. body mass on alternate days; 'x. monensin; PCV packet sell volume; values appearing in the same column with different superscripts are statistically significant (P < 0.05)

Administration of Monensin and Selenium 673

Table 8. Comparison of biochemical parameters in different groups of chickens during acute selenium toxicosis (mean f SD)

':. given orally per kg. body mass as a single dose; ';+ monensin; AlAT alanine aminotransferase; AspAT aspartate aminotransferase; AP alkaline phosphatase; values appearing in the same column with different superscripts are statistically significant (P < 0.05)

Discussion In agreement to o u r earlier expectations, a constant and more severe decrease in hae-

matological parameters was recorded in birds given selenium and monensin together (groups AO, BO and CO) during either acute or subacute toxicosis. Among registered parameters the PCV tended to lessen most repidly. Similarly, the biochemical parameters as AspAT, cholesterol levels and total serum protein exhibited more pronounced changes in birds administered selenium and monensin concurrently. The results indicate the appearance of pharmacological interaction between monensin and selenium. They further

Table 9. Comparison of biochemical parameters in different groups of chickens during subacute selenium toxicosis (mean rt SD)

':. given orally per kg. body mass on alternate days; 'M monensin; AlAT alanine aminotransferase; AspAT aspartate aminotransferase; AP alkaline phosphatase; values appearing in the same column with different superscripts are statistically significant (P c 0.05)

674 KHAN, SZAREK, SAEED, KONCICKI, KRASNODEBSKA-DEPTA

suggest that an enhancement of toxic reaction occurs when the substances are ad- ministered concurrently at levels applied in this experiment. It can be statedvated levels of haemoglobin observed in groups CO and CS, no s that these results are contrary to the reports describing a protective action of selenium and vitamin E during monensin toxico- ses in swine (16,18), cattle (17), and chicks (15). All of these works, however, examined an influence of a very low non-toxic dose of selenium (0.25 mg. per kg. body mass). Our con- clusions reflect the unique character of the element being essential for body metabolism at ultra levels (1, 4, 14, 19) but highly toxic when administered in excess (5, 8, 10). Another report mentioned that oral application of safe dosage of monensin together with toxic levels of selenium resulted in enhanced toxicity of the latter (1 1). This observation sup- ports our results disclosing an enhancement of toxic reactions following concurrent admi- nistration of selenium and monensin to broiler chickens. Combined effects occurring due to the substances manifested in increased mortality and lower body mass (6).

Briefly, the present experiments led to the conclusion that concurrent administra- tion of selenium and monensin at toxic levels resulted in exasperated toxic response in broiler chickens which in turn had been produced by embellishment of toxicosis in- ducing properties of both examined substances.

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