Document Type : Research Paper
Authors
1 PhD student in Poultry Nutrition, Department of Animal Science, Faculty of Agriculture, Islamic Azad University Karaj Branch, Alborz, Iran.
2 Professor, Department of Animal Sciences, Faculty of Agriculture, Islamic Azad University Karaj Branch, Alborz, Iran.
3 Assistant Professor, Department of Animal Sciences, Faculty of Agriculture, Islamic Azad University Karaj Branch, Alborz, Iran.
Abstract
The present study was conducted with the aim of the effect of different levels of branched-chain amino acids (BCAA) (L-valine, L-leucine and L-isoleucine) in low protein diets on performance, carcass characteristics and immune system in broiler chickens. For this purpose, a number of 480 one-day-old male and female broilers of Ross 308 strain with an average one-day weight of 42.75±0.47 g were used. This experiment was carried out as a factorial 3x2 in the form of a completely randomized design with 6 treatments and 4 replications. The experimental diets included three levels of BCAA (0, 10 and 20% higher than the standard) and two levels of crude protein (standard or 10% lower than the standard). The mutual effects of raw protein and BCAA showed that the use of 20% BCAA in the standard diet improves body weight gain and feed conversion ratio compared to the low protein diet with standard BCAA. Also, the level of 20% BCAA was able to compensate for the decrease in dietary protein, and the increase in body weight and feed conversion ratio were similar to the standard treatment. The level of 20% BCAA in the diet of broiler chickens increased the percentage of heterophils and the ratio of heterophils to lymphocytes compared to the low protein diet with standard branched amino acids (P<0.05). In general, it was found that BCAA supplementation is vital for improving carcass characteristics, immune system and performance of broiler chickens in low-protein diets.
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