The Protective Effects of Korill Product on Carp Fingerlings Reared in High Densities and Challenged with Albendazole Treatment

Abstract

The objectives of the present study were to evaluate the potential of the Korill (KO), a product based on krill oil, supplemented in fish feed (5 g/kg feed) to alleviate density-induced stress in carp fingerlings, and its protective capacity in case of anthelmintic drug administration (ABZ—albendazole). Thus, the fish were divided into four groups: LD (low density with normal feed), LD-KO (low density with KO supplementation feed), HD (high density with normal feed), and HD-KO (high density with KO supplementation feed). During the first trial, the fish held under different densities were fed normal feed and KO feed for two months, following a 2 × 2 factorial experimental design. In the second trial, seven fish per tank were subjected, for one week, to albendazole treatment (administered daily by an oral dose of 5 mg/kg body weight). For both trials, blood and plasma samples were used to quantify hematological and biochemical parameters. The results showed that the KO diet alleviated the negative impact of ABZ treatment on liver function and the metabolic profile of carp fingerlings reared in high densities. In addition, KO feeding improved lysozyme activity (LZM) and therefore the immune status of the fish, and reduced oxidative damage in the liver, demonstrated by a decrease of malondialdehyde (MDA) content and an increase of total antioxidant capacity (TAC).