Post-hatch L-Threonine Supplementation to Low Protein Diets Influences the Growth Performance and Immune Response of CARIBRO Vishal broiler Chickens

Abstract

Two experiments were conducted to evaluate growth performance, immune responses and carcass traits of CARIBRO Vishal broilers fed dietary L-Thr in low protein diets without or with the balance of Lys and Met. Broilers fed 85% CP diet with Thr alone showed depressed daily weight gain (linear, p=0.004), daily feed intake (quadratic, p=0.031) and higher FCR (linear, P=0.008) at d 21 (exp. 1) whereas, birds fed low CP diets but supplemented with Thr and balance of Lys and Met exhibited similar (p>0.05) growth rate as that of control diet (exp. 2). Incremental Thr levels increased (p<0.05) the immune and digestive organs weights, and enhanced antibody responses against SRBC and PHA-P antigens in both experiments. Thr inclusion increased (p<0.001) total protein and globulin in both experiments. Dietary crude protein in broiler diets could be reduced up to 85% of fast-growing broilers’ requirement with adequate supplementation of 3 limiting amino acids (Lys, Met, and Thr) for CARIBRO Vishal broiler chicks. Dietary L-Thr supplementation enhanced the immune status of broiler chickens fed low CP diets.