Effects of dietary threonine and crude protein on growth performance, carcase and meat composition of broiler chickens

Abstract

1. The aim of the study was to investigate the effects of dietary threonine (Thr) and crude protein (CP) in maize-soybean meal based diets on the growth performance, carcase traits and meat composition of broiler chickens and to determine the dietary Thr requirement for optimum performance (weight gain and feed conversion efficiency (FCE)) at 0 to 3 weeks and 3 to 6 weeks of age. 2. Two basal diets that differed in CP (191.3 or 179.7 and 176.7 or 165.4 g/kg at 0 to 3 and 3 to 6 weeks, respectively) were formulated to have identical contents of Thr (6.0 and 5.4 g/kg), energy (12.97 and 13.39 MJ ME/kg) and other essential amino acids except for Gly + Ser. Basal diets were supplemented with L-Thr from 0.6 to 1.8 g/kg in 0.6 g/kg increments. Broiler chicks (540) were randomly allocated to 9 dietary treatments with 6 replicates of 10 (5 female, 5 male) chicks. 3. A significant interaction between dietary CP and Thr was found for feed intake, body weight (BW) gain and FCE. Increasing Thr supplementation improved feed intake, BW gain and FCE, especially in high CP diets in both feeding periods. 4. Incremental increases in dietary Thr increased breast yield at both CP levels and drumstick yield only on high CP diets. The proportion of thigh decreased with Thr concentration. Liver weight was significantly reduced by Thr supplementation; abdominal fat was not affected. 5. Estimated Thr requirements for FCE increased as dietary CP increased according to an exponential model. This model indicated higher Thr requirements than those of broken-line models for growth performance.

Meal Pattern of Male Rats Maintained on Amino Acid Supplemented Diets: The Effect of Tryptophan, Lysine, Arginine, Proline and Threonine

“…Threonine content ranging from 5.5 to 7.8 g/kg of dietary intake was reported to improve the food intake and weight gain of broiler chickens [30], and optimal growth requires a specific lysine to threonine ratio in pigs [56]. However, both of the above experiments utilized quantities lowers than that of our experimental 50-g/kg diet.…”

“…Arginine is a precursor of nitric oxide and an inducer of growth hormone release [28,29], as well as proline production. Threonine was reported to improve food intake and weight gain [30]. Moreover, it was hypothesized that the central nervous system controls food intake by detecting dietary protein content and quality through the sensing of specific circulating amino acids, such as lysine [31].…”

Effect of different levels of lysine and threonine on carcass characteristics, intestinal microflora and growth performance of broiler chicks

“…They also found that level of 110% of threonine, compared to 100%, did not create a significant change in the liver and heart yields. Ciftci and Ceylan (2004) reported that incremental levels of threonine increased breast yield, but it decreased the thigh yield and liver weight at the starter period. Rosa et al (2001) observed no significant effect on liver yield by different levels of threonine.…”

Effects of Dietary Threonine Levels and Stocking Density on the Performance, Metabolic Status and Immunity of Broiler Chickens

“…However, Ojano-Dirain and Waldroup (2002) reported that Thr requirement of the growing broiler is greater than those recommended by NRC (1994). Ciftci and Ceylan (2004) estimated the digestible Thr was 6.9 g kgG 1 for growing phases. Our results may be related to optimal hygienic conditions.…”