EFFECTS OF DIETARY SOYBEAN OIL REPLACED WITH BLACK SOLDIER FLY LARVAE OIL ON GROWTH PERFORMANCE, PLASMA BIOCHEMICAL INDEXES AND LIVER LIPID DROPLETS OF JUVENILE YELLOW CATFISH

To evaluate the effects of soybean oil (SO) replacement by black soldier fly (Hermetia illucens) larvae oil (BSFLO) on growth performance, plasma biochemical indexes and liver lipid droplets of juvenile yellow catfish (Peltobagrus fulvidraco), BSFLO was used to replace 0 (control diet, T0), 20% (T20), 40% (T40), 60% (T60), 80% (T80) and 100% (T100) of SO in the basal diet, respectively. A total of 840 juvenile yellow catfish with an initial weight of (2.12±0.01) g were randomly divided into 6 groups for a 56-day trial with 4 replicates in each group and 35 per replicate. The results showed that, the weight gain rate, specific growth rate, feed conversion ratio, survival rate, feeding rate and protein efficiency of juvenile yellow catfish were not affected by BSFLO replacements (P>0.05). There were no significant difference in CF, VSI, HSI and IPF among all the groups (P>0.05). The crude protein, crude fat, total phosphorus as well as water content in whole body were not affected by BSFLO replacement (P>0.05). The apparent digestibility of dry matter, protein, fat, phosphorus and energy among all the groups were not significantly different (P>0.05), but the apparent digestibility of calcium in the T60 and T80 groups were significantly higher than that in T100 group (P<0.05). Except for HDL cholesterol, other serum biochemical indices were not significantly affected (P>0.05), but HDL cholesterol were significantly higher in T60 and T80 groups than in control group (P<0.05). No significant difference in antioxidant ability was found (P>0.05), and the concentrations of the anti-inflammatory factor IL-10. The proinflammatory factors IL-6, IL-8 and TNF-α in the BSFLO replacement exceeded 40% were significantly higher than those of control group (P<0.05). Oil red O staining showed that the BSFLO had no significant effect on liver fat content (P>0.05). In conclusion, BSFLO can be used to completely replace SO without significantly affecting the growth performance, body indexes, body composition, apparent digestibility of nutrients, antioxidant indexes and liver lipid droplets of juvenile yellow catfish. Based on growth performance, BSFLO can completely replace SO in the diet of juvenile yellow cat fish, when the basic diet contains 4% SO.