Effects of Amino Acid Restriction and Age on Weights and Meat Yields of Turkeys ,

Male and female Nicholas Broad Breasted White turkeys were used to determine the effects of amino acid restriction and age on live weights and meat yields. Treatments were: 1) a full nutrient diet for both toms and hens from day-old to market age; 2) a diet consisting of 90% of current National Research Council (NRC, 1977) recommended levels of protein, lysine, methionine, and methionine plus cystine fed to toms and hens from 3 weeks to market age; and 3) a diet consisting of 90% of current NRC recommended levels of the above nutrients, fed to toms from 3 to 14 weeks and to hens from 3 to 12 weeks, followed by a full nutrient diet. Toms were slaughtered at 14, 20, and 24 weeks; hens were slaughtered at 18 weeks. Birds were weighed and deboned by hand. Individual weights were recorded for live birds, eviscerated carcasses and deboned parts. Meat yield values were calculated and statistically evaluated. Age had significant effects on toms in all weight and yield figures. Lower nutrient diets had marked detrimental effects on live weights and some yield figures at 14 weeks of age. However, by 24 weeks nearly all yields in the lower nutrient groups showed no difference from controls. There were no significant differences among dietary treatments in live weights or feed conversions of toms at 20 or 24 weeks. Thus, the lower nutrient diets were adequate for feeding toms to a market age of 20 or 24 weeks. In hens, the lower nutrient diets were not adequate for attaining suitable live weights, feed conversions, or carcass parts yields at 18 weeks of age.