Dietary lipid levels requirements of hybrid yellow catfish (Pelteobagrus fulvidraco × P. vachelli

Abstract

A 12-week feeding trial was conducted to determine the dietary lipid levels requirements of hybrid yellow catfish using pelleted diets containing six different lipid levels formulated to contain graded levels of 0.0% (control), 3.4%, 6.8%, 10.2%, 13.6%, and 17% of dry matter. A total of 504 juveniles with an average initial body weight of 8.77±0.012 g were randomly divided into 6 groups containing 3 triplicates with 28 fish per tank and fed each of the experimental diets. Results showed that maximal final body weight, weight gained and specific growth rate were significantly higher in the groups fed 3.4%, 6.8%, and 10.2% compared with that of groups fed 13.6% and 17.0% (P < 0.05). Feed conversion ratio and protein efficiency ratio were significantly lowered in the 6.8% and 10.2% groups (P < 0.05). The hepatosomatic index had no significant difference (P > 0.05) while the viscerosomatic index significantly decreased in 6.8% and 10.2% groups. White blood cells, red blood cells, hematocrit and platelets levels significantly increased in the decreased dietary lipids levels (P < 0.05) while hemoglobin had no observed significant difference (P > 0.05). Serum alanine aminotransferase, aspartate transaminase, total protein, total cholesterol, triglyceride and glucose were significantly influenced by the dietary lipid levels. Liver superoxide dismutase and catalase concentration decreased significantly in the 6.8% and 10.2% groups. Malondialdehyde increased in 6.8% and 10.2% groups. Glutathione peroxide showed insignificant results (P > 0.05). Study results suggested that, dietary lipid levels containing 3.4%,6.8% and 10.2% significantly influenced growth, blood function, antioxidant status and strengthened immune response in hybrid yellow catfish while higher dietary lipid levels (13.6% and 17.0%) decreased body weight and weakened immunity.