Influence of proteinreduction and supplementation with essential amino acids in diets on growing and slaughtering performance of turkeys

In a feeding trial with 60 turkeys phase feeds with normal levels of protei n and lysine, methionine and threonine (FG1), phase feeds with lower levels of protein (- 10 % relative), but lysine, methionine and threonine levels as in FG1 (FG2) and phase feeds with lower levels of protein (as FG2), but relatively 10 % higher levels of lysine, methionine and threonine (FG3) wer e used. The following criteria were recorded: growing and slaughtering perf ormance, valuable parts of the carcass, chemical composition of the carcass and the organoleptic quality of breast meat. The trial period was 11 weeks . Each feeding group consisted of 4 boxes with 5 animals each. At the start of the trial the live weight of the turkey chicken was 55 g. After 4 weeks of the growing period average live weight of animals of the feeding group FG1, FG2 and FG3 was 0.93. 0.94 and 1.02 kg, after 8 weeks 3.72, 3.72 and 4 .01 kg and after 11 weeks 6.94, 6.87 and 7.35 kg, respectively. The feed co nversion rate in FG1, FG2 and FG3 for the whole growing period was 2.13, 2. 31 and 2.19, respectively, The carcass weight of the animals of FG3 was 0.3 0 kg heavier than in the other two feeding groups. No influence of differen t protein supplementation was observed on heart and liver weight. Weight of gizzard was decreasing from 134 g in FG1 to 126 g in FG2 and 114 g in FG3. The breast meat of FG3 showed the best value for tenderness, juiciness and taste of all feeding groups. The present trial shows, that a lower level o f protein can be easily compensated with a higher level of lysine, methioni ne and threonine in the ration.