Valine Deficiency.

Abstract

Experiments were designed to investigate the effect of feeding diets deficient in one or more of the three branched-chain amino acids (BCAA) on the performance of 3-wk-old male broilers. In the first experiment, levels of .96 and 1.46% Leu, .52 and .82% Ile, and .65 and .95% Val were used. Feeding the lowest combination of the three BCAA resulted in weight gain (WG) and feed conversion ratio (FC) of 344 g and 1.59 g:g, respectively. These parameters were not improved by adding dietary increments of the three BCAA individually. The greatest response, however, for both WG (435 g) and FC (1.41 g:g) was obtained by the addition of the three BCAA simultaneously. Chicks fed the low-Val diets in combinations with added levels of Ile and Leu exhibited feather and leg abnormalities. A second experiment was designed to investigate the effect of Val deficiency on feather protein, feather amino acids, and calcium content of the bone. Three treatments were used: a BCAA-deficient diet with .96% Leu, .52% Ile, and .63% Val; a Val-deficient diet, which contained 1.37, .82, and .63% of Leu, Ile, and Val, respectively; and a Val-supplemented diet, which was the same as the previous diets except that the Val content was .83%. Valine deficiency significantly decreased WG (243 g), FC (1.69 g:g), bone calcium (134 mg/g dry bone), and feather protein (82.7% of wet weight). Valine deficiency also decreased the level of Cys in feathers, but increased those of Asp, Glu, Met, Tyr, His, and Lys.(ABSTRACT TRUNCATED AT 250 WORDS)