A Study on The Yolk Metabolism of Embryos and Hatchlings in Chinemys reevesii

The water content of eggs,yolk,posthatching yolk and hatchlings averaged for 68.87%,61.47%,60.75% and 76.43% respectively.The dry mass of eggs,yolk,hatchlings and posthatching yolk averaged for 2.2915±0.2101 g,1.3071±0.2913 g,1.2305±0.2994 g and 0.2681±0.0241 g,respectively.The lipid content of them averaged for 18.03%,31.76%,19.30% and 32.10%,respectively.The energy value of yolk,posthatching yolk,hatchlings averaged for 6.71 kcal/g DM,6.75 kcal/g DM and 4.10 kcal/g DM.The utilization coefficient of energy of the yolk was about 77.54%.Under the condition of fasting food,both the fresh mass of posthatching yolk and the size of yolk scar in the hachlings showed the negative linear regression correlation with time.The yolk scar and posthatching yolk disappeared at the 9th and the 15th day after hatching respectively.