Effects of Amino Acids on Olfactory-Related Receptors Regulating Appetite in Silver Pomfret

Abstract

Background: Amino acids are common components of the natural prey of fishes, and even single amino acid can bind olfactory receptors of fishes and induce appetite, which is regulated by hormones. Silver pomfret (Pampus argenteus) is one of the most preferred commercial marine fish species in many Asian countries and performs a significant appetite for jellyfish. Aspartic acid, glycine, and cysteine are high content amino acid in jellyfish, so we investigated the effect of three amino acids (aspartic acid, glycine, and cysteine) on olfactory-related receptors regulating appetite in silver pomfret (Pampus argenteus).Results: The fish showed significant attractant responses to these amino acids in water, which were also observed to improve the ingestion rates of the fish. Next, we conducted transcriptomes of the olfactory epithelium (OE) and identified 34 olfactory-related receptor genes were including olfactory receptors, trace amine-associated receptors and vomeronasal receptors genes, and we examined these genes in the OE and appetite-related genes (GHRL and LEP in gut/stomach and NPY, AgRP, and POMC in brain) by RT-qPCR. The olfactory-related receptor genes were significantly expressed in amino acid groups, and the appetite-related genes were most significantly expressed in aspartic acid group. Conclusions: Thus, olfactory-related receptors induced by amino acids might regulate appetite in silver pomfret through the OE-brain-gut/stomach axis. Using these data, we identified some effective amino acid phagostimulants which could be supplied in silver pomfret diet, and the results improved our understanding of the mechanism of olfactory-related receptors regulating appetite in fish.