| Peking duck is the most excellent meat-type breed and plays the important role in meat-type duck breeding. With the development of the market, breast muscle development has become a major goal in the selection of meat type poultry, but a few research have been done on the growth rule and on its genetic parameters. This article has two goals, the first one is studying the growth rule of the pectoral, the leg meat and entrails of Peking ducks, the second one is making out the relationship between the growing traits and several biochemical parameters by estimating the genetic parameters of these traits.1 The study on the growth rule of some characters of Peking duck400 healthy young Peking ducks was randomly chosen from Z4 line and W2 line at the birth, every line has 200 and 100 ducks in every sex. The ducks were divided into four groups according to line and sex. They were simultaneously fed in the pen. Ducks were weighed after 12h deprived feed once a week from the first week to the sixth week. After they weighed every week, 15 ducks were randomly chosen from each line and each sex for measuring body size and then slaughtered for measuring the pectoral weight and leg meat weight.The result showed that there are difference among the lines, the weeks and the sex. From the result, we can see the Logistic function was fitted for describing the growth rule of the pectoral weight and the leg meat weight. The pectoral grows later than the leg meat. The pectoral grows fast from 30 to 48 days while the leg meat grows fast from 11 to 32 days.2 The study on the growth rule of the entrailsAt every weekend of the feeding period, 15 ducks were chosen from each line (Z4 line and W2 line) and each sex for weighing their entrails that had been taken out the content except the cholecyst. The measured entrails include heart, liver, spleen, esophagus, glandular stomach, gizzard, intestine, pancreas, trachea and cholecyst.The result showed that organs grow at different rate.cholecyst and trachea is serotinous while the others are premature. Among the premature organs, the differentiation growth rate of pancreas and intestine is the least that indicated that pancreas and intestine is the most premature. All the fact illuminated that digested organs grow fast at the early time which made good for surviving.3 The genetic analysis of growing traits and some biochemical parameters220 healthy Z1 line ducks of 36 families were fed to 6 weeks old. At the weekend of 6th week, the body size and body weight of the ducks were measured after having been deprived feed for 12h.After that let blood from the heart and separated the serum for measuring the biochemical parameters. After slaughtering the ducks, we weighed the pectoral, the leg meat and the other organs. We used the software MTDFREML estimating genetic parameters and breeding values and fixed effect of 32 characters that included growing and body size characters and biochemical characters. We estimated the heritability with single trait animal model. The heritability of some characters were higher than 0.3. The characters included body weight, slaughter body weight, pectoral weight, QuanJingTang, subcutaneous fat yield, breast meat thickness, the bulk of the pectoral, the shankbone length and fat yield. While some characters had the lower heritability which was lower than 0.06, these characters included leg meat weight, subcutaneous fat weight, leg meat yield, the back subcutaneous fat thickness, neck length, HDL/CHO, UA and CRE. The left traits' are about 0.2.Pectoral weight has the higher positive phenotype and genetic correlations with breast width, breast depth, breastbone length and the bulk of the pectoral. The genetic correlation between the pectoral weight and the length of the breastbone is 0.5. The length of the breastbone has the negative correlations with subcutaneous fat yield and abdominal fat yield. So we can get that we may select the pectoral character by selecting the length of the breastbone.The serum TP has the heritability of 0.2. The genet...
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