Enhancing the nutritional profile of African sharptooth catfish ( Clarias gariepinus ) through dietary supplementation with natural minerals and probiotic Escherichia coli 39-SN.

Abstract

Feed additives composed of natural minerals and probiotics are increasingly explored in aquaculture to improve fish health and meat quality while reducing antibiotic dependency. Zeolite and vermiculite, due to their adsorptive and ion-exchange properties, enhance mineral bioavailability, whereas probiotics, such as Escherichia coli 39-SN improve digestive function and nutrient assimilation. This study aimed to evaluate the effects of dietary inclusion of zeolite or vermiculite in combination with E. coli 39-SN on the chemical, mineral, and amino acid composition of African sharptooth catfish ( Clarias gariepinus ). A total of 150 catfish were divided into three groups: A control group fed a standard diet, and two experimental groups receiving diets supplemented with either 5% zeolite or 5% vermiculite, each combined with 0.1% E. coli 39-SN. The trial lasted 87 days under controlled aquaculture conditions. Post-trial, muscle tissues were analyzed for moisture, fat, protein, ash content, energy value, mineral content (e.g., iron, zinc, and magnesium), and amino acid profiles using standardized laboratory methods. Fish in the experimental groups exhibited improved nutritional profiles compared to the control. Notably, the zeolite + probiotic group showed the highest total amino acid content (34.63%) and significant increases in essential amino acids, such as leucine and phenylalanine. Vermiculite + probiotic supplementation yielded the highest fat content (0.69 g/100 g) and increased concentrations of iron and zinc. Both experimental groups demonstrated improved energy values, elevated mineral levels, and enhanced biological value of the muscle tissue. No signs of stress or cannibalism were observed, indicating good tolerance to the diets. The synergistic use of natural minerals and E. coli 39-SN significantly enhanced the chemical and nutritional quality of C. gariepinus muscle tissue. These findings suggest that such dietary strategies offer a promising alternative to antibiotics and can enhance the commercial value of aquaculture products. Future studies should explore dose optimization, long-term health effects, and the immunomodulatory potential of E. coli 39-SN in fish.