Comparative effects of different fish meal sources on gut microbiota in rice field eel (Monopterus albus)

This study aimed to evaluate the effects of using red fish meal (PRF, Peruvian red fish meal) and four types of white fish meal (NZWF, New Zealand white fish meal; NPWF, North Pacific white fish meal; RWF, Russian white fish meal; DWF, Danish white fish meal) as dietary protein sources on the gut microbial community in rice field eel (Monopterus albus), in order to identify the optimal fish meal type. Gut microbiota analysis revealed that the abundance of Bacteroidota was higher in the white fish meal groups than in the Peruvian red fish meal group (>70% vs ~50%), with significant enrichment of Muribaculaceae and Bacteroides. Network modules 1 and 2 showed strong positive correlations with growth/immune indices. Differential abundance heatmap analysis showed that North Pacific white fish meal and New Zealand white fish meal clustered into a healthy cluster, while Peruvian red fish meal formed a separate cluster. White fish meals are superior to red fish meal, with North Pacific white fish meal demonstrating the best overall performance in terms of beneficial bacterial network.