Shrimp Pleopods as a Novel Feed Item in the Diet of Adult Seahorses

There has been a growing interest in identifying alternative feed ingredients and additives for aquaculture. Although seahorses generally do not accept commercial aquafeeds, among the residues of shrimp processing, the legs-or pleopods-resemble small crustaceans and may be accepted as frozen prey by adult animals. The aim of this study was to evaluate and compare the nutritional composition and lipid profile of marine shrimp (Xiphopenaeus kroyeri) pleopods (Plop) and a conventional food item, shrimp (Litopenaeus vannamei) post-larvae (Ptla), and to assess their effects on the performance of adult seahorses (Hippocampus reidi). In addition, the effects of pleopod as a single food source on body reserves and reproductive potential were evaluated. The diets were assessed for caloric content, proximate composition, and lipid profile. Twenty adult specimens of H. reidi were subjected to a 90-day trial to assess performance, and a subset of 10 individuals was further evaluated for histological parameters. Plop exhibited a higher proportion of polyunsaturated fatty acids (PUFAs) with chains shorter than 20 carbons compared to Ptla, while both diets presented adequate levels of highly unsaturated fatty acids (HUFAs; chains of 20 carbons or more). In this study, Plop resulted in improved animal performance. More than 80% of the individuals evaluated exhibited medium to high body reserves, along with a progressive increase in hepatocyte vacuolation and in both the size and number of vitellogenic oocytes. Considering its easy accessibility, low commercial cost, and the fact that Plop does not require culturing systems, it represents a promising alternative feed resource for ornamental aquaculture and public aquaria.