Abstract

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a multifunctional neuropeptide belonging to the glucagon/secretin superfamily. Its role in fish growth and immunity has been previously demonstrated using different administration routes such as injection or immersion bath. The present study evaluated the physiological effects of a new feed formulation containing Clarias gariepinus synthetic PACAP-38 administered to rainbow trout (Oncorhynchus mykiss) fingerlings. With this aim, a new oiled formulation containing the peptide was developed and two diets with different PACAP concentrations were prepared. After two months of administration, dietary supplementation with PACAP markedly improved the PUFA content in muscle, increased the total number of caliciform cells within the intestinal villi and modulated the transcription of some of the studied cytokines in head kidney. This study suggests new potential outcomes in further advancing of the use of small peptides as feed additives and formulations to improve the quality of culture fish fingerlings.