Abstract
This study evaluates low protein diets with amino acid supplement on growth, biochemical markers and muscle amino acids profile in broilers under high ambient temperature. A total of 480 one-day-old chicks were allocated into three treatments with four replicates (n = 40). Control fed optimal protein and optimal amino acids which contains 23% and 21% crude protein (CP) with 65% methionine + cysteine/ lysine (Met + Cys/Lys) and 55% threonine/lysine (Thr/Lys), LPOA (low protein and optimal amino acids) which contains 21% and 19% CP with 65% Met + Cys/Lys and 55% Thr/Lys and 3. LPHA (low protein and high amino acids) which contains 21 and 19% CP with 74% Met + Cys/Lys and 67% Thr/Lys, respectively during the summer months (The temperatures 32 +/- 3 degrees C, and the relative humidity 72.5% +/- 4). Birds fed LPOA diets significantly highest body weight, while those fed LPHA recorded significantly the lowest body weight (BW). Dressing percentages not revealed significantly affected by reducing dietary protein levels, while the blood plasma total protein, albumin, and globulin were not significant differences due to dietary low protein. Chicks fed LPHA diets recorded the highest liver content of malonaldehyde. It could be concluded that feeding the Cobb 500 broilers on low protein diets with the same amino acid levels had no adverse effect on growth, carcass markers, and liver function, however increased amino acids levels to low protein diets may led negative impacts for the broiler performance under high ambient temperature.