title: Investigations of threonine requirements of broiler chicks fed diets based on grain sorghum and soybean meal.
abstract: Three trials were conducted to estimate the threonine (Thr) requirement of male broiler chicks. Chicks 7 days of age were fed a grain sorghum-soybean meal diet containing .59% Thr, supplemented with 0, .05, .09, .15, .22, .27, or .28% L-Thr. Levels of basal and supplemental amino acids were confirmed by ion-exchange chromatography. Diets were fed for 18 or 20 days, depending upon the trial. A corn-soybean meal diet analyzed to contain .90% Thr was used for comparison. Results of the three trials were pooled for determination of Thr requirements. A significant improvement in gain was observed when the basal grain sorghum-soybean meal diet was supplemented with .09% supplemental Thr (total .68% Thr). No further improvements in gain were observed at higher levels of Thr supplementation. Body weight gain of chicks fed the Thr-supplemented diets did not differ significantly from that of chicks fed the corn-soybean meal control diet. For maximum feed utilization, the Thr requirement was .79%, as estimated by regression analysis. This is in agreement with the .80% requirement suggested by the National Research Council in 1984. Feed utilization of chicks fed the corn-soybean meal diet was significantly better than that of chicks fed any of the grain sorghum-soybean meal diets regardless of the level of Thr supplementation.
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000378:metabolism*; D008297:Male; D009751:Nutritional Requirements; D013912:Threonine / Q000378:metabolism*
chemical_list: D013912:Threonine