Effect of Dietary Lipid Level and Herb Mixture on Growth of Parrot Fish, Oplegnathus fasciatus

A feeding trial was carried out to Investigate the effect of lipid level and herb mixture in the diets on growth of juvenile parrot fish, Oplegnathus fasciatus. Two plicate groups of fish averaging 4.5 g were fed four experimental diets containing herb mixture (0 and 5 g/kg diet) at each of two lipid levels $(8\%\;and\;16\%)$ for 8 months from summer to spring (water temperature, $7.2-25.4^{\circ}C)$. Weight gain improved with increasing dietary lipid level or supplementation of herb mixture during the first 4 months feeding period. Weight gain of fish fed the diet containing $16\%$ lipid level was significantly higher (P<0.05) than that of fish fed the diet containing $8\%$ lipid level. Weight gain of fish fed the diet with herb mixture was significantly higher (P<0.05) than that of fish fed the diet without herb at the $16\%$ lipid level. Feed efficiency was influenced by dietary lipid level or herb mixture during the first 4 months. On the other hand, weight gain and feed efficiency were not affected by dietary lipid level and herb mixture after 4 months until end of feeing period. Survival of fish fed the diet containing $8\%$ lipid without supplementation of herb mixture was the lowest among the groups (P<0.05). Lipid contents of liver and viscera tended to increase with increasing dietary lipid level during the first 4 months feeding period, however muscle lipid content was not influenced by dietary lipid and herb. Total cholesterol of serum was influenced by dietary lipid level during the first 4 months feeding period. These results indicate that an increase of dietary lipid level from $8\%\;to\;16\%$ and supplementation of herb mixture can improve growth performance of juvenile parrot fish when water temperature is optimum for growth such as the summer season in Korea.

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