Ideal Dietary Threonine Requirements for Commercial Broilers to Optimize Economic and Production Performance

250 commercial broiler birds (Ven Cobb) were used in the present research to evaluate the graded concentration of digestible threonine (100, 75, 70, 65 and 60% of the digestible lysine) in order to optimize the threonine requirements for improving the productive performance in commercial broiler diets.

The chicks were divided into five treatments, each containing ten replicates and each with five chicks, owing to a completely random design (CRD). During the experiment, a corn-soy based diet was prepared and supplemented with digestible threonine at decreasing concentration of digestible Lysine.

The concentration of digestible threonine in broiler diet did not influence the weekly body weight gain and feed intake during experimental period. However, FCR was significantly (P<0.05) affected during 1^st and 2^nd weeks with better FCR recorded in control group (100% Cobb recommended threonine), whereas in 4^th week, comparable better FCR was also recorded in 60% of the digestible threonine (T5) supplemented group. The dietary variation in threonine did not influence the slaughter parameters (dressing percentage, ready-to-cook yield and thigh weight), serum biochemical parameters (total protein), antioxidant enzymes activity (lipid peroxidation) and livability. Among all groups the highest net revenue over the feed cost (Rs.71.09/bird) was generated in 60% of the digestible threonine supplemented group. Therefore, the findings of the present study, concludes that digestible threonine concentrations during the pre-starter, starter and finisher phases at 60% of the digestible lysine (0.708, 0.630 and 0.570%, respectively) are optimum for getting good economic returns without having negative impact on growth performance, slaughter parameters, serum biochemical parameters and livability in commercial broilers.