中华鲟幼鱼对慢性拥挤胁迫的生长、摄食及行为反应

设置低、中、高3个初始养殖密度(1 g/L、4 g/L、8 g/L),进行40 d的养殖实验,研究慢性拥挤胁迫对子二代中华鲟(Acipenser sinensis Gray)幼鱼生长、摄食及行为的影响.研究表明,慢性拥挤胁迫对子二代中华鲟的生长和摄食有显著影响,体质量、体质量特定生长率、体长特定生长率、日增重随着养殖密度的升高显著降低(P<0.05),实验结束时,高密度组肥满度显著低于中、低密度组(P<0.05);各实验组的摄食率随着养殖密度的升高而降低,饵料系数随着养殖密度的升高而升高(P<0.05).慢性拥挤胁迫对子二代中华鲟的行为也有显著的影响,随着养殖密度的增大,表现为呼吸频率、摆尾频率和游动速度显著加快等应急行为.研究结果表明高养殖密度对中华鲟的生长、摄食和行为存在显著的负面作用,不利于中华鲟幼鱼生长发育.

Effects of chronic crowding stress on growth, feeding, and behavior in Chinese sturgeon Acipenser sinensis F2 juveniles

Chinese sturgeon(Acipenser sinensis) are an endangered anadromous species listed on the IUCN Red List. The species was characterized as a national level key protected animal of China in 1988 and fell under the protection of CITES Appendix II in 1998. Because of their perilous status, there is considerable interest in artificial breeding and species conservation. To aid development of conservation breeding programs, we evaluated the effects of chronic crowding stress on growth, feeding, and behavior in F₂ Chinese sturgeon. The fish were cultured at three stocking densities (low: 1 g/L, medium: 4 g/L, high: 8 g/L) for 40 d to evaluate the influence of stocking density on growth, feeding and behavior. Density had a significant effect on growth and feeding. The body weight, growth efficiency, specific growth rate, and daily weight gain decreased significantly as stocking density increased. The feeding rate for the experimental groups also decreased as the stocking density increased and the feed conversion ratio increased as the stocking density increased. Density also had a significant effect on behavior because of chronic crowding stress. The breathing frequency, tail wagging frequency, and swimming distance increased with an increase in stocking density.