Resumo

POTENCA, Alexandra; MURAKAMI, Alice Eiko; OSPINA-ROJAS, Iván Camilo  e  MULLER FERNANDES, Jovanir Inês. Digestible valine-to-lysine ratio in diets for broiler chickens. Rev. mex. de cienc. pecuarias [online]. 2015, vol.6, n.1, pp.25-37. ISSN 2448-6698.

This study was developed to evaluate the effect of the digestible valine:lysine ratio (dig Val:Lys) in the diet of 1 to 14-d-old broilers on performance, feathering, diameter and profile of muscle fibers. A total of 1,080 1-d-old Cobb 500 broilers were distributed in a completely randomized experimental design with five treatments and six replicates of 36 birds each. Treatments consisted of different dietary ratios of dig Val:Lys (66, 71, 76, 81 and 86 %) in the period between 1 and 14 d of age. The dig Val:Lys ratio did not influence (P>0.05) bird performance. Nevertheless, there was a positive linear effect (P<0.05) of dig Val:Lys ratio on back feather length and feathering score of the thigh and breast. The dig Val:Lys ratio had a quadratic effect (P<0.05) on the diameter of muscle fibers, with an estimated dig Val:Lys ratio of 76 %. The muscle fiber profile was not influenced (P>0.05) by the treatments. It was concluded that a Val:Lys ratio of 66 % is sufficient to maximize the performance of broilers from 1 to 14 d of age; however, a higher dig Val:Lys ratio (76 %) is needed to maximize muscle fiber growth.

Palavras-chave : Digestible amino acid; Branched-chain amino acid; Muscle fiber.

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