Tuna (<i>Thunnus alalunga</i>) Gill Extract\nAlters Gut Microbiota Composition and Increases Fecal Immunoglobulin\nA Levels in Male Mice

Intake of fish and fish-derived collagen degradants improves\nimmunity\nand intestinal microbiota composition. In this study, we aimed to\nexamine the effects of tuna gill extract (TGE) on intestinal immunity\nand the amino acid composition of mice. TGE was prepared and administered\nto male mice and splenocytes were collected from the spleen. Then,\nits effects on the intestinal immune system were compared between\nsalmon collagen peptide (SCP) and TGE. Supplementation of TGE or SCP\nat 1% significantly increased fecal immunoglobulin A (IgA) levels\nand the relative Lactobacillus spp.\nabundance in male murine intestines. Supplementation did not affect\nintestinal organic acid levels; however, hydroxyproline was detected\nin the feces from TGE- and SCP-supplemented mice. These results indicate\nthat TGE, a byproduct of fisheries, could be used to improve intestinal\nimmunity in mice.