Studies On Methionine Requirement And Amino Acid Pattern Of 5-10 Week Yangzhou Goslings

Two experiments were conducted to determined the amino acid requirement of 5-10 Yangzhou goslings in different approaches in this paper.In experiment 1, a dose-response experiment with different dietary levels of methionine was conducted to estimate optimum dietary methionine levels of 5~10 weeks Yangzhou gosling. 150 28-d-old Yangzhou goslings were divided into 15 pens with 10 birds per pen according to similar pen weight. There were 5 dietary treatments, each containing 3 replicate pens. Five levels of dietary methionine (Met) were 0.23%, 0.33%, 0.43%, 0.53% and 0.63%. The results were as follows: there were significant difference among groups in growth performance, carcass characteristics and serum parameters. The feed /gain of goslings feeding 0.43% Met were lower than those feeding 0.23% Met (P<0.05). Goslings feeding 0.43% and 0.53% Met were higher than other treatments on the items of slaughter percentage, semi-eviscerated percentage, eviscerated percentage, breast meat percentage and leg muscle percentage, and goslings feeding 0.53% and 0.63% Met were lower than goslings feeding 0.23% Met (P<0.05). Content of BUN of goslings feeding 0.43% and 0.53% Met were lower than goslings feeding 0.23% Met (P<0.05), and content of TP of goslings feeding 0.53% Met were higher than goslings feeding 0.23% Met (P<0.05). The nitrogen retention rate of goslings feeding 0.43% Met were significant higher than goslings feeding 0.23% Met (P<0.01), higher than goslings fed 0.63% Met (P<0.05), and the nitrogen retention rate of goslings feeding 0.33%,0.53% Met were higher than goslings feeding 0.23% Met (P<0.05). According to the results, when the dietary protein level was 15.82% the optimal Met requirement of Yangzhou goslings of 5~10 weeks was 0.43%~0.53%.In experiment 2, on the principle of factorial method, some parameters of the model were estimated using compared slaughter test with growing goslings and nitrogen balance test with adult geese, and amino acid requirements of 5-10 wk Yangzhou goslings were assessed by the model. The results were as follows: difference of carcass and feathers amino acid composition between Yangzhou goslings of different age was not significant (P> 0.05), the amino acid compositions of Yangzhou goslings for growth from 5 to 10 wk of age were: Lys 100, Met 44, Thr 36, Leu 90, Iso 41, Arg 59, Val 45; the amino acid compositions of adult Yangzhou geese for maintain were: Lys 100, Met 46, Thr 62, Leu 121, Iso 68, Arg 93, Val 76; the total amino acid compositions of Yangzhou goslings from 5 to 10 wk of age were: Lys 100, Met 46, Thr 43, Tyr 36, Leu 98, Iso 48, Arg 70, Val 54; the total amino acid requirements (the percentage of the feed%) of Yangzhou goslings from 5 to 10 wk of age were: Lys 0.72%, Met 0.33%, Thr 0.31%, Leu 0.71%, Iso 0.35%, Arg 0.51%, Val 0.39%.