The effect of feeding commercial diets on the development of juvenile crucian carp (Carassius carassius, L.). Part 1: Skeletal deformations

Abstract

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.

Skeletal Development and Deformities in Tench (Tinca tinca): From Basic knowledge to Regular Monitoring Procedure

“…Starter diets have been found to induce a high incidence of external body deformities (77.9-96.4%) [13], probably due to an imbalanced content of some key nutrients. In this regard, Kasprzak and collaborators [34] showed a better skeletal development of crucian carp juveniles when fed natural feed (Chironomidae sp. larvae) rather than two popular commercial diets, suggesting that basic commercial diets might be inadequate for the intensive rearing of crucian carp juveniles.…”

“…In tench larvae, the first ossified vertebra was identified in larvae ranging 6-12 mm of SL. The Weberian (1-4), the prehemal vertebrae (5-23), caudal (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38), and preural vertebrae (39)(40) suffered a very rapid ossification process, being fully mineralized in larvae with 12-17 mm of SL. Indeed, the last elements to be ossified in the axial skeleton were the ones located at the dorsal, pectoral, pelvic and anal fins, evidencing that an intense swimming activity in early tench specimens for feeding onto live preys might be required.…”

Performance of Co-Housed Neon Tetras (Paracheirodon innesi) and Glowlight Rasboras (Trigonostigma hengeli) Fed Commercial Flakes and Lyophilized Natural Food

“…All in all, it appears that this simplistic approach of comparing only the BW measurements did not reveal any crucial discrepancies between the tested dietary groups, which was the exact outcome we expected to occur. As we have shown in our previous nutritional experimentation on juvenile crucian carp, Carassius carassius [ 82 , 90 ], similar growth rates do not always give the whole picture of the condition of aquarium-reared fish, particularly in regard to the structure of digestive organs or the skeleton. Therefore, additional laboratory analyses (focused on body internals) were performed to confirm or deny whether the studied feeding regimes were truly indifferent in terms of impacting both of the ornamental species.…”

“…This phenomenon begins with insufficient intake/absorption of the three crucial macroelements (Ca, P, Mg) [ 112 ], which are then emergently recovered from skeletal tissues for more important physiological purposes, either via osteoclastic resorption [ 113 ] or halastatic demineralization [ 114 ]. Unfortunately, these processes have not been studied extensively in freshwater fish, but we made such observations in our trial on juvenile crucian carp [ 90 ], where the use of commercial feeds significantly decreased bone hardness and resulted in vertebral anomalies. Skeletal double staining was, therefore, conducted in the current study to inspect whether such remarks could be made for housed ornamentals fed exclusively on artificial flakes.…”

“…The latter species, however, probably revealed early signs of demineralization in all four groups when compared to the smaller “Initial” fish group sampled at the beginning of the study. After all, Cypriniformes tend to develop skeletal pathologies when fed exclusively with commercial feeds [ 90 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 ], which possibly could have been happening here, as well. Notwithstanding, such statement requires to be validated in future trials, which should last much longer than three months.…”