| There are four parts in the study.The first party is Studies on growth and development for Chinese Taihe chicken. 186 Chinese Taihe chicken were randomly divided into six groups ,which were fed the same diets and bred from 0 to 12 weeks of age .At biweekly intervals the average body weight and feed intake were recorded ,meanwhile one bird from each group with the similar weight to average body weight was killed and the weights of various internal organs were measured ,carcass and internal organs were homogenized and analyzed for the activities of a-amylase and trypsin in duodenum contents were also measured .The results showed as following : ( 1) The Chinese Taihe chicken grew slowly before 4 weeks of age ,the growth was fitting to the exponential function equations which was y=29.7759e0.4432x(R~2=0.9878, n=180, P<0.01), while it grew rapidly after 4 weeks of age and the growth was fitted to the linear equations which was y=-120.0910+72.5165X ( R2=0.9952, n=180, P<0.01) ,X means weeks of age and y means body weight in the equations;(2) The peak of growth and development of internal organs was before 8 weeks of age, but it was not in coincidence in each organ. (3) The activities of a-amylase and trypsin in duodenum contents increased with age before 8weeks of age, but it increased slowly at 0-4 weeks age, which was probably a limited factor to growth.The second party is studies on the requirement and patterns of essential amino acids for Chinese Taihe chicken of 0-12weeks. Mathmathics models have been formulated to calculate the essential amino acid requirements for growing Chinese Taihe chicken in early stage. A requirement was taken as the sum of the needs for maintenance, for gain in carcass weight without feathers, and for the feathers. The maintenance requirement was considered to be the sum of the needs for replacing skin and intestinal losses and for the obligatory creatinine excretion in the urine. Parameters used in the models were obtained from the comparative slaughter trial and nitrogen balance trials with adult Chinese Taihe chicken. The essential amino acid requirements were calculated with the constructed models. The results showed as following: (1) the nitrogen amounts of carcass very significantly linearly correlated to body weight (p<0.01), the regression equation was expressed as follow: CN (mg)=66.4720+27.1761BW(g), (R2=0.9960 p<0.01, n=84). (2) Nitrogen amount of feathers (FN, mg) was regressed on body weight (BW, g), following equation was obtained: FN (mg) =0.8688BW~1.3892 (g), (R~2=0.9831, p<0.01, n=84). (3) The replacement needs for skin nitrogen loss was determined at 213.41mg/d for adult male Chinese Taihe chicken (1.6kg) creatinine excretion in these birds was 4.04mg/d. When fed an N-free diet, 1.6kg adult male Chinese Taihe chicken excreted a total of 246.1 0mg/d endogenous nitrogen. The net protein requirements for maintenance was estimated: PRM=11.24mg/gw075. (4) Per g body weight gain contained 27.1761mg. (5) Carcass nitrogen for growing Chinese Taihe chicken in early stage, but feathers nitrogen in per g body weight gain increased with age. The essential amino acid requirements were slightly higher than growing laying hens but lower than that of broiler chicks. The amino acid patterns changed with weeks of age.The third party is Studies on the Digestible Methionine Requirements of Chinese Taihe chicken of 0-12weeks.A grouped feeding trial, nitrogen balance trial and metabolism trial for Chinese Taihe chicken were conducted to study the effects of dietary methionine levels on performance, nitrogen retention and serum urea nitrogen concenteation and to determine the total and digestible methionine requirements of Chinese Taihe chicken in early stage. The results showed as following: during 0-4 weeks the total and digestible methionine requirements of Chinese Taihe chicken fed on a diet (19.24% crude protein, metabolizable energy 12.26MJ/kg and 0.26% supplemental methionine) was 0.44% and 0.41% of dietary levels, respectively. During 4-9 weeks, based on a diet (17.37% crud...
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