Effects of Food Enrichment Based on Diverse Feeding Regimes on Growth, Immunity, and Stress Resistance of Nibea albiflora.

Food enrichment represents a novel feeding strategy for aquaculture. In the current study, juvenile Nibea albiflora (average weight 29.65 ± 0.13 g) were used and three feeding regimes (A-commercial diet; B-a diet comprising 90% commercial feed and 10% ice-fresh Palaemon gravieri; C-a diet consisting of 90% commercial diet, 5% ice-fresh Palaemon gravieri and 5% live Perinereis nuntia; named control group, Group 1, and Group 2) with comparable nutrient compositions: were designed to establish the food enrichment model and explore the effects of such feeding strategies on the fish. The cultivation period was 60 days, and the physiological, pathological, and RNA-seq analyses were performed to evaluate the effects. The results showed that the food enrichment feeding strategy significantly enhanced fish growth performance, immunity, and stress resistance without increasing the unit production cost (UPC). Furthermore, the tri-combined food feeding (C) was better than the two-combined food feeding (B). Liver transcriptomic analysis revealed that, in the comparison between the control group and Group 1, the up-regulated genes (alox15b, gng7, hif1a, ppara, and pla2g) and down-regulated genes (ins, gck, il4i1) influenced fish physiology and further improved growth. Similar to the comparison between the control group and Group 2, the major functional genes included ugt, nlrp3, mx1, col1a, gst (up-regulated), and map2k1, myc, mmp9, wnt7, socs3 (down-regulated) that participated in regulating the body growth, immunity, and stress resistance. The up-regulated genes (ins, mhc2, foxo3, ppara, and mx1) alongside the down-regulated genes (egfr, fos, cyc, myc, and mmp9) probably contributed to the enhanced efficacy of the tri-combined food feeding compared to the two-combined food feeding. In summary, this study demonstrates the beneficial effects of such a food enrichment model on the fish and provides empirical evidence supporting the implementation of the feeding strategies in the healthy culturing of the fish.