Organic Acids in BroilerClinical Trials

Citric Acid

Materials and Methods

108 one day old straight run broiler chicks (Hubbard Classic) for a period of 35 days.

The chicks were randomly divided into 4 equal treatment groups (A, B, C and D) each having 27 chicks.

Each treatment was subjected to 3 equal replications of 9 chicks each.

Treatment

1. A: Control diet2. B: Control diet + 0.5% citric acid3. C: Control diet + 0.5% acetic acid4. D: Control diet + 0.5% citric acid + 0.5% acetic acid with drinking water.

Evaluation

Weight gain Feed conversion ratio Mortality Dressing percentage Economy of broiler production were recorded and calculated. At the end of experiment, two birds from each treatment

were selected randomly to record the dressing yield, organs weight and cut up parts

Live Weight Gains Dietary treatments

A B C D Age (weeks) / Initial weight 46.2 46.1 46.4 46.1

1 84.5 88.7 73.1 70.3

2 210.3 219.8 175.0 176.6

3 286.4 299.2 247.6 281.0

4 396.8 447.2 368.5 372.2

5 403.5 451.5 424.7 507.9

0-4 977.9 1054.0 864.2 900.1

0-5 1381.4 1506.3 1289.0 1408.0

Final body weight (g) 1427.6± 1552.4 1335.4 1454.1

Feed Intake

Age (weeks) Dietary treatments

A B C D

1 122.3 124.1 120.0 117.0

2 320.9 325.9 292.2 301.1

3 514.5 532.9 499.1 561.1

4 738.2 804.4 769.9 801.9

5 1217.2 1331.2 1348.8 1320.8

0-4 1696.0 1787.0 1681.0 1781.0

0-5 2913.2 3118.6 3029.9 3101.9

FCR

Age (weeks) Dietary treatments

A B C D

0-2 1.5 1.5 1.7 1.7

0-3 1.7 1.6 1.8 1.9

0-4 1.7 1.7 1.9 1.9

0-5 2.1 2.1 2.4 2.2

Carcass Characteristics

Parameters Dietary treatments

A B C D

Live weight (g) 1146.7 1300.0 1150.0 1150.0Organ weights (% live weight)

Killed weight 89.6 89.9 89.2 89.9

Shank weight 4.6 4.9 4.9 4.9

Head weight 3.9 3.9 3.5 3.2

Giblet weight 7.3 7.2 7.3 7.2

Skin weight 16.2 15.1 15.7 14.8

Visceral weight 7.8 7.7 7.3 7.7

Carcass yield 54.98 55.4 51.9 56.8

Production Cost Parameters Dietary treatments

A B C D

Total feed cost 1464.48 1568.04 1523.3 1559.49

Total chick cost 378 378 378 378

Management cost1 484.59 537.35 502.68 566.2

Total acid cost ----- 60.31 90.77 156.27

Total production cost (Tk.) 2327.07 2543.73 2494.75 2503.69

Total production cost (Tk.)/kg live weight 60.35 60.7 69.21 63.77

Total sale priced (Tk.) 3084.48 3352.32 2883.6 3140.64

Total net profit (Tk.) 757.48 808.59 388.25 636.95

Net profit (Tk.)/kg live weight 19.7 19.3 10.7 16.2

Propionic Acid

Effect of PA on Growth

The mechanism of growth promotion of PA is seems to be:1. The reduction of pathogenic burden by reducing gut ph2. Increasing digestibility3. Improving the permeability of the intestinal mucosa and

thus increase the rate of absorption and also increase the utilization of protein, amino acids, minerals and other nutrients.

Cont. …

Additions of Luprosil® NC (containing 53.5% PA) @ 0.4% showed significant body weight gain of broiler chicken at 49 days of age compared to unsupplemented group (Izat et al., 1990).

Cont. …

An experiment with organic acid salt (1g/kg each of calcium propionate, ammonium formate and calcium lactate) as substitute for antibiotics (virginiamycin @ 0.5 g/kg as antibiotic) showed numerically higher live weight and live weight gain in organic acid salt supplemented group compared to antibiotic supplemented group (Paul et. al., 2007).

Cont. …

Marcos et al. (2004) reported that broiler fed organic acid mixture (70% formic acid and 30% PA) @ 0.25 and 0.50% with diet showed higher gain compared to birds fed higher level (1.0 and 2.0%) organic acid mixture.

Significant improvement in body weight and weight gain of turkey poult by supplementing MC (Myco curb containing PA) @ 0.625 and 1.25% was reported by Roy et al., (2002).

Effect of PA on Feed Intake and Feed Conversion

PA reduces the pH of feed PA improves the hygienic condition of feed PA improves palatability and increases feed intake (Higher

level of PA reduces feed intake) PA increases permeability of mucosal cell of the intestine

which increases the rate of utilization of nutrients. PA improves feed conversion rate.

Cont. …

Cave (1984) reported that when PA was included in the feed up to levels of 100 g/kg, from 0 to 28 days, voluntary feed intake of broiler chicks was decreased with increasing dietary levels of acid.

Cont. …

Organic acid salt (calcium propionate, ammonium formate and calcium lactate @ 1g/kg) as an alternative to antibiotic (virginiamycin @ 0.5 g/kg) showed that the cumulative feed intake in broiler was significantly higher in antibiotic treated group than other, whereas improved feed conversion ratio (FCR) was found in organic acid salt supplemented group (Paul et. al. 2007).

Cont. …

In a study, Celik et al. (2003) observed better FCR of turkey chicks supplemented with organic acids (propionic caid, formic acid, acetic acid) as compared to unsupplemented group.

Effect of PA on Carcass Yield

It is well established that PA used as growth promoter improves the rate of utilization of all nutrients especially protein which results better dressing percentage.

Cont. …

Female broilers fed 7.3 kg/ton (0.8%) of Luprosil® NC (53.5 % PA) resulted in a significant improvement in carcass dressing percentage (Izat et. al., 1990).

Significant effect on carcass yield of broiler chicken fed diet supplemented with PA was reported by Hume et al. (1993).

Antibacterial Effect of Propionic Acid

The antimicrobial activity of PA is related to:1. Reduction of pH.2. PA is lipid soluble in the undissociated form, in which it is

able to enter the microbial cell. PA can dissociate inside the bacterial cell and break down the DNA structure in the bacterial cell nucleus.

pH and Bacterial Growth

The pH level in specific areas of the gastro intestinal tract (GIT) is a factor which establishes a specific microbial population, and also affects the digestibility and absorptive value of most nutrients.

Most of the pathogens grow in a pH close to 7 or slightly higher.

In contrast, beneficial microorganisms live in an acidic pH (5.8-6.2) and compete with pathogens (Ferd, 1974).

Cont. …

In addition, lowering the pH by organic acids reduces the pathogenic microbes from GIT and improves nutrient absorption (Boling et al., 2001).

Propionic acid effectively inhibits the growth of E. coli bacteria in the animal’s gastrointestinal tract.

At the same time it does not inhibit the growth of Lactobacillus bacteria.

Addition of PA in feed has a potential role in reducing Salmonella spp. in the chicken intestine.

Cont. …

Kwon et al. (2003) reported buffered propionic acid (BPA) markedly decrease the growth of Salmonella and other intestinal anaerobic microbes by decreasing PH from 7 to 5 and maximum inhibitory effect was found at 3% level of BPA in broiler.

The results of this study indicated that the growth inhibitory effect of PA against S. typhimurium strains was enhanced by a decrease in pH and suppressed by anaerobiosis, suggesting that the growth response of S. typhimurium to PA in the chicken intestine might be affected by the environmental conditions such as pH and anaerobiosis.

The Minimum Inhibiting Concentration (MIC) of PA

Test-organisms (Bacteria) MIC % of propionic acid

Staphylococcus aureus 0.25

Bacillus subtilis 0.25

Aerobacter aerogenes 0.5

Escherichia coli 0.25

Escherichia freundii 0.125

Proteus vulgaris 0.2

Pseudomonas aeroginosa 0.25

Pseudomonas fluorescens 0.25

Serratia marcescens 0.25

Propionic Acid as Mould Inhibitor and Preservatives

Fungal inhabitations in feedstuffs during storage seem to be inevitable without the presence of effective preservative(s) if the humidity is over 16% with atmospheric temperature higher than 200C (Ronald, 1996).

Cont. …

Fungal growth on feed can substantially decrease its quality, as the moulds thriving there in consuming majority of fat, protein, carbohydrate and even mineral elements, leading subsequently to stuff discolorations, heating, mustiness and biochemical transformations yield the accumulation of toxic substances in most cases.

Cont. …

Bacteria and yeast contamination in compound feed have a negative impact on the intestinal flora, resulting in nutrient losses and negatively influencing the feed intake of animals.

High microbial counts in feedstuffs not only result in a reduced nutrient value, but they also have a negative impact on palatability, which consequently results in a reduced feed intake and performance.

To avoid these problems animal feed products have to be free of mold and have a long storage life. For this PA is an ideal animal feed preservative.

Cont. …

The presence of growing moulds and produced mycotoxins in feedstuff decreases feed intake, efficiency and rate of feed, while increasing the risk of infection and reproduction disability (Lin and Chen, 1995).

The fungal toxins such as aflatoxins, zearalenone, ochratoxin and fumonisin, among those aflatoxins are dominant (Hamilton, 1985 and Zou et al., 1997).

Cont. …

The strategy for the control of mould growth, suitable for feed industry, is the careful application of antifungal preservative(s) (Holmquist et al. 1983 and Hamilton, 1985).

An ideal feed preservative must be efficacious, inexpensive, corrosion-free and safe to the animal (Holmquist et al. 1983 and Lin and Chen, 1995).

Preservatives available today are mainly synthetic chemicals such as propionate as well as acetic, sorbic and formic acids (Goering and Gordon, 1974 and Bartov, 1983).

Cont. …

Propionic acid has been proven to show the broadest efficacy among all organic acids against fungi and yeasts.

The Minimum Inhibiting Concentration (MIC) of Propionic Acid on Fungi

Test-organisms (Fungi) MIC % of propionic acid

Aspergillus niger 0.25

Aspergillus flavus 0.25

Aspergillus versicolor 0.5

Chaetomium globosum 0.125

Penicillium expansum 0.125

Penicillium funiculosum 0.125

Penicillium spinulosum 0.1

Penicillium roqueforti 0.125

Conclusion

As an antimicrobial feed additive, PA is efficient than that of other organic acids. It creates favorable response on performance and overall health condition of avian species. It is also popular as preservatives.

Furthermore, like antibiotic growth promoter it has no risk of microbial resistance.

Therefore PA with its performance and health enhancing properties is an effective alternative to feed antibiotics in food animal production.

Formic and Propionic Acids

Materials and Methods

360 one day old commercial broiler chicks of either sex were randomly allotted to 8 dietary treatment groups.

Each group was having three replicates comprising 15 birds in each replicate.

Treatment

1. Group 1: basal diet2. Group 2: basal diet + virginiamycin (0.05% of feed)3. Group 3: basal diet + formic acid at 0.10% (FA-0.1) 4. Group 4: basal diet + formic acid at 0.15% (FA-0.15) 5. Group 5: basal diet + propionic acid at 0.10% (PA-0.1) 6. Group 6: basal diet + propionic acid at 0.15% (PA-0.15) 7. Group 7: basal diet + combination of formic (0.05%) and

propionic (0.05% each) acids (FA+PA-0.1) 8. Group 2: basal diet + commercial gut acidifier (CGA-0.1) at

0.1% level.

Production Performance

Body weight gain (g) Cumulative feed intake (g) Feed conversion ratio (FCR)

Control 1,946 3,620 1.86

AGP-0.05 1,954 3,441 1.76

FA-0.1 1,926 3,465 1.79

PA-0.1 1,915 3,445 1.80

FA-0.15 1,882 3,369 1.79

PA- 0.15 1,917 3,476 1.81

FA+PA-0.1 1,956 3,316 1.70

CGA-0.1 1,928 3,358 1.74

Conclusions

Based on the feed efficiency and economics, it can be inferred that combination of formic (0.05%) and propionic (0.05%) acids at 0.1% level in the diet of broilers is found to be beneficial and can replace the antibiotic growth promoters in broiler feed.