Molecular Characterization and Expression Response of Ghrelin, GLP-1 and PYY to Fasting, Dietary Lipid, and Fatty Acids in Silver Pomfret (Pampus argenteus)

Ghrelin, glucagon-like peptide-1 (GLP-1), and peptide YY (PYY) are potent hormones mediating food intake according to the nutritional status in fish. However, limited information is available on these genes and their expression in response to nutrition in silver pomfret (Pampus argenteus). A comparison analysis revealed thatghrelinand GLP-1 were relatively conserved in marine fish. PYYa and PYYb shared a low identity and were clustered to different PYY branches.Ghrelin,pyya, andpyybmRNAs were highly expressed in the brain, whileglp-1was highly expressed in the gills and liver. TheghrelinmRNA expression was relatively high an hour post-feeding and decreased after 3 to 72 h of fasting. Theglp-1mRNA expression was increased after 6 to 24 h of fasting. ThepyyamRNA expression was increased after 72 h of fasting, while thepyybexpression remained stable during fasting. The diet with 14% lipid promoted the expressions ofglp-1,pyya, andpyyb, but inhibited theghrelinexpression. Theghrelinexpression in the intestine was increased after palmitic acid, oleic acid (OA), linoleic acid (LA), α-linolenic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) incubation. OA decreased the expression ofglp-1and increased the expression ofpyya. The expression ofpyybwas downregulated by LA, DHA, and EPA. These results suggest the importance ofghrelin,glp-1, andpyyin coordinating food intake in response to fasting, dietary lipid concentration, and fatty acids in silver pomfret.Keywords:ghrelin;glp-1;pyy;fasting;lipid content;fatty acids;silver pomfretKey Contribution:This study provides insight into howghrelin,glp-1, andpyyrespond to fasting, dietary lipid concentration, and fatty acids in silver pomfret.