Compensatory growth in gibel carp (carassius auratus gibelio) after the stress of stocking density

摘要

The research was performed to investigate the compensatory growth in gibel carp (Carassius auratus gibelio) after the stress of stocking density; the 8-week growth trial was performed in a proper system of 12 fibreglass tanks. Four different density groups were marked as C (control group), D-1/2, D-1/4 and D-1/8, and the biomasses were converted into 1.98 kg/m(3), 3.96 kg/m(3), 7.91 kg/m(3) and 15.82 kg/m(3) respectively. Under density stress, the final weight, protein retention efficiency (PRE), feed conversion efficiency (FCE) and specific growth rate (SGR) of groups D-1/2, D-1/4 and D-1/8 were significantly lower than group C (p < 0.05) and reduced with the increase in density. In the period of the recovery of activity space (5-8 weeks), groups D-1/2, D-1/4 and D-1/8 have significantly higher feeding rate (FR), FCE and SGR than group C. There was no significant difference in body weight between group D-1/2 and group C, while the body weight of group D-1/4 and group D-1/8 was still significantly lower than group C. The hepatosomatic index (HSI) of the D-1/8 group was extremely low before and after the restoration of activity space (p < 0.05). Under stress, the lipid contents of group D-1/4 and group D-1/8 were significantly lower than group C. Subsequently, the recovery of activity space, the lipid content of group D-1/8,D- was still significantly lower than group C. The results obtained indicated that the D-1/2 group (3.96 kg/m(3)) successfully lead to wholly compensatory growth, while the D-1/4 (7.91 kg/m(3)) and D-1/8 (15.82 kg/m(3)) group partially lead to compensatory growth. So, higher density leads to poor compensation effect.