Probiotic Bacteria in Gastro-Intestinal Tract of Hybrid Catfish Fed Insect Protein Meal

Abstract

The evaluations of insects’ protein as viable alternative protein source in fish diets are gaining more attention revealing that the protein has more comparative advantage than other protein sources. Therefore, this study was conducted to isolate and identify (using phylotypic and genotypic methods) bacteria isolates in the gastrointestinal tract (GIT) of African hybrid catfish fed supplemented grasshopper meal. Four feeding diets were adopted in this study; Diet A (conventional feed), Diet B (100% Grasshopper meal), Diet C (50% fishmeal and 50% Grasshopper meal) and Diet D (100% Fish meal). At the end of the 12- week experimental period, the fish were sacrificed for their GIT contents to determine bacteria diversity. In the catfish fed diet A, the bacteria isolates identified were Streptococcus pyogenes, Enterobacter aerogene, Staphylococcus aureus, Shigella flexneri, Escherichia coli, Leuconostoc latis and Klebsella pneumonia. In catfish fed diet B, Bacillus subtilis, Lactococcus bulgaricus, Lysinibacillus macroides, Lysinibacillus capsici, Stenotrophomonas pavanii and Lysinibacillus sp were isolated. Similarly, the fish fed diet C recorded the presence of Bacillus subtilis, Lactococcus bulgaricus, Lysinibacillus sp., Staphylococcus aureus, Lysinibacillus macroides, Stenotrophomonas pavanii and Enterobacter aerogene. The bacteria isolated in the GIT of fish fed diet D were Bacillus cereus, Staphylococcus aureus, Pedicoccus acidilactis, Escherichia coli, Salmonella typhi, Leuconostoc latis and Shigella flexneri.  Probiotic bacteria were more in fish fed with diets B and C, an indication that the different ratio of supplemented grasshopper meal is good for the fish, as they have the potentials to boost the fish immune system and improve the microbial balance of its gastro-intestinal tract.