Interaction between ambient temperature and supplementation of synthetic amino acids on performance and carcass parameters in commercial male turkeys

An experiment with male turkeys was conducted to test the hypothesis that t urkey production performance responds positively to extra crystalline amino acid supplementation (lysine, methionine, and threonine) when subjected to a high ambient temperature regimen (HT) in the grower period. Two diets we re formulated to provide lysine, methionine, and threonine concentrations t hat either 1) met the breeder recommendations or 2) contained 10% higher ly sine and methionine concentrations from 22 to 134 d of age and 10% higher t hreonine concentration from 22 to 68 d of age. Both diets were fed at two t emperatures (15 or 25 C) from 42 d of age onward. At 134 d of age, turkeys on the HT had generally lower BW than those on the low temperature regimen (LT). Up to 68 d of age and from 106 to 134 d of a ge, feed intake of turkeys on the HT was significantly lower than that of t urkeys on the LT. Up to 42 d of age, feed conversion ratio (FCR) of turkeys on the HT were significantly lower than those of turkeys on the LT. Signif icant treatment interactions were observed from 22 to 41 d of age. Turkeys fed the amino acid-supplemented diets on the LT had significantly reduced F CR, whereas these on the PIT did not respond. From 69 to 105 d of age, turk eys on the HT that were fed the supplemented diets had significantly increa sed FCR, but there were no dietary effects among turkeys on the LT. There w ere no consistent diet effects on growth performance or carcass yields. Bre ast meat yields of turkeys on the LT were higher (33.5 vs 32.1%), and drum yields were lower (12.7 vs 13.0%), than those of turkeys on the HT. There w ere no significant amino acid balance x ambient temperature effects on proc essing yields. The hypothesis of this experiment could be rejected as production performan ce did not respond positively to extra supplementation of lysine, methionin e, and threonine when subjected to an PIT.