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Response of broiler chicks to low-protein diets supplemented with amino acids administered through feed or drinking water under heat stress conditions
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Abstract: An experiment was conducted to investigate the response of broiler chicks (0 - 7 weeks of age) reared under heat stress conditions to low -protein diets supplemented with amino acids administered either through feed or drinking water.
Five hundred and forty Arbor Acres broiler chicks were used in a 3 x 3 x 2 factorial design of treatment. Three protein levels were used, 23, 20 and 18 %CP in the starting period (0 -3 weeks of age), then switched to 20 (as a control), 18 and 16 %CP in the finishing period (4 - 7 weeks), respectively. Three amino acid levels to serve as 100, 110 or 120% ofNRC, (1994) recommendation administered either through feed or drinking water. Chicks were reared in high environmental temperatures (28-35.9°C; 49-56% relative humidity) using artificial gas heaters.
Results indicated that body weight gains of broiler chicks fed low -protein diets (20 or 18 %CP during 0-3 weeks and 18 or 16 %CP during 4 -7 weeks of age) supplemented with amino acids (Met, Lys and Thr) were not significantly different ftom those fed of the 23/20 % CP-control diet. There were no significant differences in feed conversion of chicks fed low-protein diet and that of the 23% CP -control diet. Increasing amino acid levels ftom 100 to 110 or 120 % of the NRC (1994) requirements administered either in the feed or in the drinking water did not improve body weight gain or feed conversion of chicks reared under heat stress conditions. There were no significant influences of feeding low -protein diets supplemented with amino acids administered either in feed or drinking water on carcass traits, but a significant increase in abdominal fat was associated with lowprotein diet (18/16% CP-diet). Also, there were no significant influences of treatments on total lipids, cholesterol, T3, T4 or immune response. Economical efficiency (feed cost /Kg dressed weight) was reduced with feeding low-protein diets supplemented with amino acids. It is concluded that feeding low-protein diet supplemented with amino acids 100 % of the requirements (Met, Lys, and Thr) administered in the feed gave similar performance and better economical efficiency than those obtained ftom the control diet. However, increasing amino acid supplementation over 100 % of the requirements administered through feed or drinking water had no beneficial effects for broilers grown under heat stress conditions.
Key words: low -protein diets, amino acids, broiler performance, heat stress
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| Publication year |
2005
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| Pages |
759-773
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| Availability location |
معهد بحوث الانتاج الحيوانى-شارع نادى الصيد- الدقى- الجيزة
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| Availability number |
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| Organization Name |
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| City |
كفر الشيخ
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| serial title |
Animal Production Research Institute Second Conference & Regional Symposium on Buffalo Production
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| Author(s) from ARC |
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| External authors (outside ARC) |
عادل زكى سليمان
جامعة القاهرة
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| Agris Categories |
Animal feeding
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AGROVOC
TERMS |
Amino acids.
Broiler chickens.
Heat stress.
Lysine.
Methionine.
Performance testing.
Protein content.
Protein restricted diets.
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| Publication Type |
Conference/Workshop
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