肉食性和杂食性鱼类饲料蛋白需求的比较营养能量学研究

Comparative studies were conducted by growth trial and respirometry to investigate the difference in protein requirement and energetics mechanism in carnivorous Chinese longsnout catfish (Leiocassis longirostris Günther)and omnivorous (Carassius auratus gibelio). The results showed that the protein requirement for Chinese longsnout catfish and gibel carp is 45.5% and 38.4%, respectively. Growth of two fishes increased with increased dietary protein to the optimal protein level and (45% and 35%) and kept constant. Feeding rate was not affected by dietary protein levels except that the increase in feeding rate of gibel carp at the highest protein level. Feed conversion efficiency increased with increased dietary protein levels in Chinese longsnout catfish while there was no significant difference in gibel carp. Protein efficiency ratio and retention in gible carp decreased with increased dietary protein levels while there was no significant difference in Chinese longsnout catfish. Energy retention in two fishes increased with dietary protein levels up to optimal level and then decreased. The proportion of food energy lost faecal production was not affected by dietary protein levels in two fishes while the proportion of excretion increased with dietary protein. The proportion of food energy channeled into metabolism and SDA was not affected by dietary protein levels. At the optimal protein level, the energy budget of Chinese longsnout catfish and gibel carp could be described as:Chinese longsnout catfish:100C = 11.64F＋8.29U+37.98R+38.08G；Gibel carp:100C = 16.49F +7.17U+44.66R+23.75G；Where C, F, U, R and G stand for food energy, faecal production, nitrogenous excretion, metabolism and growth.In conclusion, the proportion of food energy lost in excretion and metabolism in Chinese longsnout catfish is lower than those in gibel carp while the proportion of food energy deposited in growth is higher in Chinese longsnout catfish.

鱼类对蛋白质的需求较高，占饲料成本大部分，不同食性鱼类对蛋白质需求存在着差异，饲料蛋白质水平对不同食性鱼类生长和能量代谢影响差异及其机制尚不清楚。本项目拟从生物能量学角度探讨饲料蛋白水平对肉食性和杂食性鱼类生长和能量代谢影响及其差异的机制。在理论上阐明鱼类蛋白需求与食性的关系及机制，实践中可为饲料工业合理配方提供科学指导。