The influence of L-valine supplementation of the diets on the live weight of broiler chickens (between 1−28 days of age)

Abstract

According to the latest literature data valine should be considered as the fourth limiting amino acid in broilers (Corrent, 2009). Consequently, it appears necessary to set up trials that can facilitate to determine the valine requirement of high-performance broilers more accurately. Our study was aimed at determining how the valine supplementation of the diets affects the weight gain, feed intake and feed conversion rate of broiler chickens. The trial used 1600 Ross-308 roosters in 5 replicates (320 birds/treatment). Birds were fed starter diets between 1–14 days of age, and grower diets between 15–28 days of age. The control and trial diets were corn-soy based. Crystalline L-valine was used to supplement starter diets at the rate of 0−0.91−1.82−2.73−3.63 g/kg, and grower diets at the rate of 0−0.82−1.63−2.44−3.26 g/kg. Birds were individually weighed on days 1, 14 and 28 of age. Feed intake of the birds was determined by cage (40 birds per cage). Trial data were subjected to variance analysis. In case of the significant treatment effect the statistical reliability of differences among treatments was verified by Tukey test (SAS, 2004). According to the results of the trial the crystalline L-valine supplementation does not affect significantly the weight gain of the birds during the started diet phase (P≥0.05). At the end of the grower phase (day 28 of age) the weight of the birds was not affected by the lower valine dosages (0.82 and 1.63 g/kg diet); higher valine dosages (2.44 and 3.26 g/kg diet), however, increased their weight in a statistically verifiable manner (P≤0.05) The feed intake and feed conversion rate of the broilers were not influenced by the treatments (P≥0.05). Our data highlight the fact, that the valine contents of the diet influence the performance of broiler chickens and this should be clarified further in future studies.