Effects Of Water Temperature And Food Types On Energy And Nitrogen Budget And Metabolism Of Chinese Mitten-handed Crab (Eriocheir Sinensis) Juveniles

This experiment was conducted to determine the effects of water temperature and food types on nitrogen and energy budget of Chinese mitten-handed crab (Eriocheir sinensis) juveniles. The crab (average weight 3.5g ) had been fed with fish meat and corn at four levels of water temperature (18℃,22℃,26℃and 30℃) respectively for 8 weeks. The trial was carried out in quintuplicate to octuplicate groups.The results indicated that:1. With the water temperature increasing, the weight gain rate of crab fed with fish meat were 31.08%,38.05%,38.70% and 42.87% respectively, and that fed with corn were 29.33%,26.89%,44.97% and 63.25% respectively. The weight gain rate of the crab fed with fish meat was significantly higher than that fed with corn at 22℃(p<0.05). At 30℃, however, it was completely reversed (p<0.05).2. Take nitrogen budget as considered, compare to the crab fed with fish meat, the crab fed with corn intake more nitrogen, but its excretion nitrogen, faecal nitrogen and the exuviae nitrogen were low. Besides, although its growth energy was significantly higher than that fed with fish meat when the water temperature was 18℃and 22℃, there was no significant difference when the water temperature was 26℃and 30℃. For the crab fed with fish meat, the food energy intake was lower while the excretion energy, faecal energy, growth energy and exuviae energy were higher than that fed with corn at the same temperature.3. Take energy budget as considered, the temperature affected the proportion of metabolism energy in food intake energy significantly, the higher the water temperature, the higher the proportion of metabolism energy. The proportions of excretion energy, faecal energy and growth energy in food intake energy of the crab fed with corn were lower than that crab fed with fish meat (p<0.05), but proportion of the metabolism energy of the former was markedly higher than the latter (p<0.05). These results indicated that higher food intake energy and lower metabolism energy resulted in higher weight gain ratio for crab fed with corn at higher water temperature.