The crucian carp (Carassius carassius, L.) is a cyprinid freshwater species, whose wild‐living populations have decreased in recent years due to an increasing competition of invasive species. Several initiatives were launched, attempting to reintroduce this fish back into its native open waters, which requires the use of crucian carp fry grown under controlled conditions. However, the use of popular commercial diets results in severe developmental abnormalities. The aim of this study was to analyse the impact of feeding natural feed (Chironomidae sp. larvae) or two popular commercial diets on the skeletal development of crucian carp juveniles. Whole‐mount staining and histological methods were used in the study. Skeletal tissues of fish fed both commercial diets were demineralized and displayed a variety of deformities, such as abnormal vertebral spines and vertebral fusion, as well as a new type of deformation, which involved the action of dorsal fin pterygiophores upon the spine. Finally, a novel analytical method was proposed, which utilizes LA‐ICP‐MS for the estimation of bone mineralization. The study proved that basic commercial diets are inadequate for the rearing of crucian carp juveniles.
Wild-living populations of the crucian carp Carassius carassius, a cyprinid fish of European freshwaters, have decreased in recent years, likely due to increasing competition presented by invasive species. Several initiatives have been launched in an attempt to reintroduce this fish back into its natural habitat, but these approaches require the use of crucian carp fry reared under controlled conditions, and the use of popular and inexpensive commercial diets has been found to result in developmental abnormalities. The aim of the current study was to analyse the impact of feeding juvenile crucian carp either natural food (Chironomidae sp. larvae) or 2 commercial diets, with a focus on the intestinal development of these fish. Histological analysis revealed significant pathologies in the alimentary tracts of fish fed both commercial diets; these included lowered hepatocyte and enterocyte proliferation, as well as shortened intestinal folds. Furthermore, the digestive enzyme activity patterns suggested a physiological state close to malnutrition. This study confirmed that basic commercial diets (at least the 2 applied) are not recommended for the rearing of crucian carp juveniles, even though initial growth rates of the fish might suggest otherwise.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.