Cottonseed protein concentrate as an effective substitute to fish meal in pike perch (Sander luciperca) feed: evidence from growth performance and intestinal responses of immune function and microflora

In conclusion, 60% of fish meal can be replaced by CPC based on the above results. However, increasing dietary CPC substitution slightly increased Firmicutes abundance and significantly decreased Actinobacteriota abundance, but the abundance of Proteobacteria in the CPC3 group was appreciably increased. An increase in Staphylococcus and a reduction of Lactobacillus were observed in the CPC2 and CPC3 groups. Igf1 expression was significantly downregulated with increasing CPC substitution. Henceforth, the above two limiting factors should be considered key breakthroughs in improving the effectiveness of replacing fish meal with CPC in pikeperch. The current findings provide a significant reference and breakthrough in improving the effectiveness of replacing fishmeal with CPC in pikeperch diets.