This study investigated the effect of n‐3 to n‐6 fatty acid ratios in broodstock diets on reproduction performance, fatty acid composition of eggs and gonads of tongue sole Cynoglossus semilaevis. Broodstock were fed five isonitrogenous and isoenergetic diets for 60 days. The supplemented lipids were prepared by a combination of fish oil and soybean oil inclusion FO (fish oil); FSO1 (fish oil: soybean oil = 7:1); FSO2 (fish oil: soybean oil = 2.2:1); FSO3 (fish oil: soybean oil = 1:1); FSO4 (fish oil: soybean oil = 1:4.3) as lipid sources with different n‐3 to n‐6 fatty acid ratios 10.40, 5.21, 2.81, 1.71 and 0.87. Results showed that relative fecundity, fertilization rate and survival rate of larvae at 7 days posthatching were all higher in broodstock fed FSO1 and FSO2 diet and significantly (P <0.05) decreased in groups fed FSO3 and FSO4 diets. The best result in starvation tolerance test was obtained in FSO2 diet. The present study suggests that n‐3 and n‐6 PUFA ratio in broodstock diet has a considerable effect on spawning performance, egg and larval quality for C. semilaevis. 相似文献
The compensatory growth, body composition and energy budget of juvenile tongue sole, Cynoglossus semilaevis (Günther, 1873), subjected to an unfavourable temperature were investigated during 56 days experiment. Fish were divided into four groups including three groups, which were reared at 16°C for 1, 2 and 3 weeks, respectively, then returned to 22°C (recorded as A1, A2 and A3) and a control group (continuously reared at 22°C, C). At the end of the experiment, the body mass was significantly higher in A1 than that in the control (P <0.05), which indicated over compensatory growth occurred in A1 fish. No significant difference was found in body mass among A2, A3 and C fish (P >0.05), which indicated complete compensatory growth occurred in A2 and A3 fish. The underlying mechanisms for compensatory growth could be attributed to an improved energetic efficiency resulting from reduced metabolic expenditure and higher feed efficiency during the period of recovery. Furthermore, the fish exposed to lower temperature for 3 weeks showed hyperphagia. The results suggested that the juvenile C. semilaevis exposed to lower temperature for a suitable period (1–3 weeks) used feed more efficiently. This approach may be a useful rearing strategy for indoor culture of C. semilaevis. 相似文献