Study Of Incubation Ecology In The Chinese Soft-Shelled Turtle (Trionyx Sinensis)

In the present work, 302 eggs of the soft-shelled turtle, Trionyx sinensis, were incubated at 25, 27.5, 30, 32.5 and 35℃. The wet and dry weights, energy content and chemical composition of embryo, shell, yolk and the other part at various incubation period were determined. The followings are the main results.1. Development of the embryo can be described well by the logistic curve. Correlations between the dry weight of the embryo (Wed': mg) and incubation time (D: day) at various temperature could be expressed by the following equations:25 ℃: Wed'=3009/(1+e^{-0.09106(D-88.4)}27.5℃: Wed'=1004/(1+e^{-0.1519(D-48.9)}30℃: Wed'=697.6/(1+e^{-0.1711(D-35.5)}32.5℃: Wed'=944.7/(1+e^{-0.1898(D-35.4)}35℃: Wed'=874.6/(1+e^{-0.1974(D-31.2)}2. There are extremely significant differences in the final embryo dry weights among different incubation temperatures. Relationship between the final embryo dry weights adjusted by the specific egg weight (mean of all experimental egg weights, 4300mg) (Wed': mg) and incubation temperature (T: ℃) is:Wed'=4159-242.7T+4.159T²3. During incubation dry weights of egg materials and egg shells decreased slightly. While water weights of egg materials were relatively stable.4. The shortest incubation period (incubation time of first hatching at each temperature) (I: day) varied with incubation temperatures (T: ℃). Their relationships can be described by the following hyperbola curve:I=30.59+109/(T-22.53)5. The embryonic energy values and total energy amounts adjusted by specific egg weight varied with incubation temperature, presenting a 'U' shape. The average energy efficiency of embryo growth is 79.27%.6. Protein content of the embryo is the lowest at about 73.5% of the incubation period. Protein amount of the embryo increased exponentially with incubation time. The protein efficiency of embryo growth is about 88.67%.7. The effects of incubation temperature on content and amount of protein and lipid of the final embryo are significant. The lipid efficiency of embryo growth is about 82.95%.8. There is an inverse correlation between ash content and egg weight. No significant differences in ash contents were observed at various temperatures. Ash of the embryo originated from egg shell was only 9.98%, most of the embryo's ash originated from egg yolk.9. About 76.02% of the embryonic calcium is provided by egg shell and the other 23.98% is by yolk. The embryo utilized about 77.09% of magnesium in yolk.10. About 52.77% of carbohydrate in yolk was consumed for embryonic metabolism, which is more than consumed protein and lipid.11. The optimum incubation temperature for T. sinensis egg is about 32.5 ℃.Some results for other preliminary study are as follows.(1) An intensive and automatic incubation room had been designed. The efficiency of egg incubation is 98.88%. Its operation is simple and the performance is trustworthy.(2) Chicken liver is one kind of favorite diet for 71 sinensis. Growth efficiency of the turtle fed on chicken liver is higher than that of the turtle fed on Jiawei artificial diet. However, the turtle which fed on liver was deficient in calcium and magnesium.(3) The ovarian weight and protein content had extremely significant differences among various seasons. There was also obvious difference in lipid content. Total energy of eggs in one clutch is about 2.91% of the female's body energy. The liver and fat body may provide energy for hibernation and reproduction.