Introduction
In the context of advancing a blue and circular economy, utilizing the full potential of African catfish (Clarias gariepinus Burchell, 1822) by-products—specifically the liver, gonads, and skin—can significantly reduce waste and enhance resource efficiency. While considerable research has focused on the nutrition (Langi et al. 2024) and nutritional content of the fillets, there remains a notable gap in understanding the potential applications of the catfish’s liver, gonads, and skin. Research shows that the liver of African catfish is rich in polyunsaturated fatty acids (PUFA) and has low concentrations of triglycerides and saturated fatty acids (SFA), particularly when the fish is fed high-protein diets (Matter et al. 2004, Taiwo et al. 2014).
The study aimed to unravel the composition of fatty acids of by-products of the African catfish within a Recirculating Aquaculture Systems (RAS) and the most suitable moment for harvesting to maximize the use of nutrients and their further potential reuse.
Material and methods
We monitored the growth in total body weight, the hepatosomatic index (HSI) , the gonadosomatic index (GSI) , the skin weight and the filet weight ( without the skin) of African catfish. Furthermore, the content of fatty acids in the liver, gonads and skin was analysed.
Results
Table 1. Total body weight, HSI, GSI, skin and meat percentages over the total body weight of African catfish at 5 different samplings (each 3 weeks) in RAS
References
Matter F, Peganova S, Eder K. Lipid concentrations of fillets, liver, plasma and lipoproteins of African catfish, Clarias gariepinus (Burchell 1822), fed diets with varying protein concentrations. J Anim Physiol Anim Nutr (Berl). 2004 Aug;88 (7-8):275-87. doi: 10.1111/j.1439-0396.2004.00483.x. PMID: 15274692.
Langi S, Maulu S, Hasimuna OJ, Kaleinasho Kapula V, Tjipute M. Nutritional requirements and effect of culture conditions on the performance of the African catfish (Clarias gariepinus ): a review, Cogent Food & Agriculture 2024, 10:1, 2302642, doi : 10.1080/23311932.2024.2302642
Taiwo OE, Usman K, Ogono TH, Osoniyi RO. Proximate and lipid profile analysis of cultured and wild african catfish, Clarias gariepinus [BURCHELL] Ife Journal of Science 2014 vol. 16, no.1.