Effects of different diets on growth，body pigmentation， serum biochemical indexes of ornamental carp （Cyprinus carpio L.）

A 8-week feeding experiment was carried out on juvenile ornamental carp Cyprinus carpio with initial weight of 2.41±（0.03）g to evaluate the effects of feed composition on growth，morphological indices， body pigmentation and serum biochemical indexes. Four diets were perpared and named diet 1（commercial ornamental carp feed），diet 2（extrusion feed），diet 3（extrusion feed with spirulina）and diet 4（extrusion feed with photosynthetic bacteria）. Each diet was assigned to triplicate groups. The results showed that：（ 1） the final wight，weight gain，condition factor（CF）and hepatosmatic index（HSI）of diet 1 were the lowest among the four diets，and the final wight and HSI were significant lower than those of other three diets；（ 2） The sequence of total carotenoids content in body surface（dorsal fin and skin）of ornamental carp was：diet 3>diet 4>diet 2>diet 1；（3）The partially serum biochemical indexes could be affected significantly by feed composition. The serum albumin and albumin-globulin ratio of diet 1 were significantly higher than those of other diets，but no significant difference was found in serum albumin，albumin-globulin ratio and alkaline phosphatase activity among diet 2，diet 3 and diet 4. In conclusion，photosynthetic bacteria and spirulina added to extrusion feed can improve the growth and body-color of ornamental carp.