Digestible Lysine Requirements of Hen Turkeys from 6 to 12 Weeks of Age

Abstract

Two floor pen trials were conducted to determine the digestible lysine requirement of hen turkeys from 46 to 57 days and 71 to 85 days of age, or what is more commonly referred to as the 6 to 12 week period. 2000 Nicholas White female poults were obtained and fed an NRC-type corn-soybean meal diet until the trials began. For the first experiment, 240 46-day-old birds were banded, weighed, computer sorted, and assigned a treatment with 8 birds per pen. In the second experiment, 240 71-day-old birds were weighed, banded, computer sorted, and assigned a treatment with 5 birds per pen. Birds in both trials were fed experimental diets with digestible lysine levels ranging from 0.85 to 1.21% in the 46 to 57 day period and 0.70 to 1.05% in the 71 to 85 day period. Two low protein diets were used and the levels of digestible lysine were obtained by titrating L-lysine HCl into the low protein diets. In order to obtain sufficient amino acid levels and nitrogen levels to support growth equal to the high protein positive control diet, synthetic amino acids were added back into the low-protein diet. Both experiments were of a complete randomized block design. For the first experiment, there were 7 treatments with 4 replicates per treatment. For the second experiment, there were 8 treatments with 6 replicates per treatment. In each experiment, the highest level of lysine was reduced to half of the replicates in order to provide space for the positive control groups which were fed a standard corn and soybean meal diet based on NRC (1994) recommendations. Experimental data were analyzed by analysis of variance and segmented analysis. Segmented analysis indicated that the digestible lysine requirements for the 46 to 57 day period to be 1.04% for body weight gain and 1.07% for feed conversion. In the second trial, the analysis indicated that the digestible lysine requirements for body weight gain and feed conversion to be 0.86% and 0.82%, respectively.