Role of Dietary Protein Source on Gut Function and Associated Genes Involved in Appetite, Growth, and Metabolism in Channel Catfish

Feeding ecology is important in both aquaculture and fisheries management. In both, efficient growth depends on optimal feed intake, nutrient utilization, and gut health, all of which are associated with the feeding ecology of the fish.  The present study evaluated the effects of different dietary protein sources on the regulation of gut health, peptides, and genes involved in appetite, growth, and metabolism. In total, 46 genes from four tissues were evaluated.  The experimental design involved four dietary treatments formulated with the following feedstuffs as the primary protein source: (A) fishmeal, (B) porcine meat and bone meal, (C) soybean meal, and (D) corn germ meal/cottonseed meal. Each diet was fed to three tanks of 20 Channel Catfish each for a period of 12 weeks. Differences in feed conversion ratio (FCR), specific growth rate (SGR), feed intake (FI), hepatosomatic index (HSI), intestinal histology, and fold-change in gene expression were observed.  Feed conversion ratio was significantly (P<0.05) reduced in Diet A, but SGR, HSI, and FI were unaffected by dietary treatment. Changes in gene expression were related to pathways involved in appetite, growth, and metabolic regulation. This study presents new perspectives on the regulation of catfish physiology associated with diet and gut function.