Endocrinological And Molecular Biological Mechanisms Of Excellent Egg Performance In Shaoxing Ducks

Endocrinological and molecular biological mechanisms of excellent egg performance in Shaoxing ducks were examined in the present paper, involving following aspects: 1. Comparison of egg performance between Shaoxing and Gaoyou ducks Laying rate and egg weight of 102 Shaoxing ducks and 52 Gaoyou ducks reared on floor were recorded. The results showed that the onset of lay in Shaoxing ducks were earlier than that in Gaoyou ducks (17 vs 37 weeks of age), the duration of 50% laying rate was longer in Shaoxing ducks than in Gaoyou ducks (39 vs 16 weeks). In addition, acute change of diet, molting, temperature and ducks density influenced the egg performance in Sbaoxing ducks. Laying rate and egg weight of 85 Shaoxing ducks reared in cage were recorded. The sequence length and the pause length were analyzed. There were two main sequence lengths that are 31.62+2.94 and 36.33+2.34 days respectively, while pause lengths are 1.91+0.27 and 4.55?.68 respectively. Laying rate of cage reared Sbaoxing ducks was improved compared to that of floor reared ducks (77.74?.21 vs 73.52?.75%, p<0.05), while egg weight (66.87?1.3 vs 66.35?.12 gram) was not affected. 2. Developmental changes of ovarian follicles, follicular cellular proliferation and apoptosis in Shaoxing and Gaoyou ducks during lay Ovary were sampled from 8 Shaoxing and Gaoyou ducks reared in cage versus on floor at 14, 23, 28, 36, 40, 51 and 59 weeks of age respectively. Their ovary weight and numbers of preovulatory follicles were recorded. The results showed that the maturity of ovary was earlier in Shaoxing ducks than that in I0I ~L*4~F~ Gaoyou ducks (17 vs 37 weeks of age). The ovary was heavier in floor reared Gao you ducks than that in Shaoxing ducks. The follicles atresia was common in Gaoyou ducks while seldom in Shaoxing ducks. There are strong positive correlations between ovary weight, preovulatory follicle numbers and laying rate, egg weight in cage versus floor reared Shaoxing ducks, while strong negative correlations in floor reared Gaoyou ducks. The first, the third and the fifth largest preovulatory follicles (F1, F3 and F5), and the small follicles (SF, diameter < 8 mm) were sampled from 5 Shaoxing and Gaoyou ducks reared on floor at 59 weeks of age respectively. Cell proliferation and apoptosis were detected using the f]owcytonietiy. The results showed that the percentages of overall and early cell apoptosis of SF were significantly higher in Shaoxing ducks than in Gaoyou ducks, while the proliferation index were lower in Shaoxing ducks than in Gaoyou ducks. 3. Changes of serum levels of growth hormone(GH), 17- ~ estradiol (E2) and binding activity of GH binding protein (GHBP-BA) in Shaoxing ducks during iay Sera were prepared from the 8 Shaoxing and Gaoyou ducks at different weeks of age respectively above-mentioned, their levels of OH and E2 were analyzed using the radio-immuno-assay (RIA), Gl-IBP-13A was analyzed using the radio -binding assay. The results showed that serum E2 level was higher in Shaoxing ducks than in Gaoyou ducks. There are strong negative correlations between serum level of GHBP-BA and ovary weight and preovulatoiy follicle numbers in Shaoxing ducks reared cage versus floor.