Studies On Amino Acid Requirements Of Gushi Chicks

Two experiments were conducted to determine the amino acid requirements of GuShi chicks in different approachs in this paper. In experiment 1,6 gradeed amounts of DL-methionine were added to maize-soybean - bone meal basal diets in each phrase(0-4 week,5-8week and 9-12week) and 600 1-day-old GuShi chicks were divided into 24 groups ,and every 4 group as a deal. Average daily gain,feed conversion ratio,concentration of blood uric nitrogen and plasma free methionine,nitrogen retention ratio were used as guidelines to determine. Results showed that diet methionine level have insignificant effect on average daily gain and nitrogen retention ratio(p>0.05),but have significant effect on feed conversion ratio,concentration of blood uric nitrogen and plasma free methionine(p<0.05). The level of Gushi chicks diet were given as follows according to all these results,0-4 week:0.39%,5-8 week:0.37%,9-12 week:0.33%.In experiment 2,we use a new formal approach to determine amino acid requirements of GuShi chicks,220 1-day-old GuShi chicks were used and 20 of them were killed to analyse the initial composition of cacarss and feather,the others were divided into 8 groups(4 male group and 4 female group)and feed with maize-soybean meal diets and sample at intervals.Body weight gain,crude protein and amino acid contents of cacarss and feather were used to calculate amino acid requirements at the basis of the model which conceived by Hurwitz in 1973. Results showed that the model could accurately determine the amino acid requirement of GuShi chicks. In the early diets of GuShi chicks, levels of Val,His,Phe and Thr were a little higher than recommendations of standard of meat type chicks compiled in 1986,but levels of Gly,Ile,Ser and Cys were much higher than the recommendations,two of the other essential amino acids Arg and Lys levels were accord with the recommendations,but Met level was lower than the recommendation and higher than the recommendation of growing laying hens. But in the lately diets of GuShi chicks, levels of essential amino acids were lower than the recommendations of 1986 standard except Gly and Ser.