Effects of dietary threonine on growth performance and carcass traits of Yangzhou geese
Shi, S.R.,Chinese Academy of Agricultural Sciences, Yangzhou (China). Poultry Inst. | Wang, Z.Y.,Yangzhou Univ. (China). Coll. of Animal Science and Technology | Zou, J.M.,Chinese Academy of Agricultural Sciences, Yangzhou (China). Poultry Inst. | Yang, H.M.,Yangzhou Univ. (China). Coll. of Animal Science and Technology | Jiang, N.,Yangzhou Univ. (China). Coll. of Animal Science and Technology
A dose-response experiment with 5 total dietary threonine (Thr) levels (0.54, 0.64, 0.74, 0.84 and 0.94%) was conducted to study the effect of dietary Thr on growth performance and carcass traits of Yangzhou geese from 0 to 8 weeks of age. Three hundred 1-day-old Yangzhou goslings were randomly allocated to 15 pens with 20 birds (10 males and 10 females) per pen according to similar pen weight. There were 5 dietary treatments, consisting of 3 replicate pens. Weight gain, feed intake and feed/gain of geese from each pen were measured at 2-week intervals from 0 to 8 weeks. At 56 days of age, four geese (2 males and 2 females) were selected randomly from each pen and slaughtered to evaluate the carcass quality. The results showed that an increase in dietary Thr resulted in an increase and then a decrease in daily weight gain in both periods. Peak daily weight gain responses appeared in geese fed the 0.74% Thr diet in both periods (36.120 and 61.96 g, respectively). Thr supplementation significantly affected feed/gain in the 0-4 week period and daily feed intake in the 5-8 week period. No significant linear or quadratic responses from Thr supplementation were observed in growth performance and carcass traits of geese except for eviscerated carcass percentage. The optimal Thr requirement of Yangzhou geese from 0 to 8 weeks of age was 0.726% for eviscerated carcass percentage. The results of our experiment reported herein would document that the Thr requirements suggested by NRC (1994) for geese up to 8 weeks of age are safe estimates; they may slightly overestimate the requirements.
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