Dietary benfotiamine in high carbohydrate diet improves growth and resistance to abrupt shift to higher salinity in the African catfish Clarias gariepinus juveniles

Benfotiamine, a synthetic provitamin B1 and a more bioavailable form, has been demonstrated to enhance growth and immune response in fish and shrimps in high carbohydrate diets. The present study aimed to determine the effects of elevated dietary carbohydrates and benfotiamine supplementation on the fry of African catfish Clarias gariepinus. Three diets were used, namely: a commercial diet specific for catfish was used as the control (C) diet, a high carbohydrate (HC) diet, and a benfotiamine-supplemented HC (HCB) diet. Results show that the HCB diet resulted in significantly higher final average body weight (FABW), weight gain (WG), specific growth rate (SGR), and significantly better food conversion ratio (FCR) than the values for both C and HC groups. In a separate test for attractability, it was demonstrated that HCB was more attractive to the catfish juveniles than the HC or C diets. Also, an experiment to determine the median lethal concentration after 96 h (96 h LC50) of catfish fry in various salinity levels was conducted and was found to be at 10 ppt salinity. This salinity level was used for the resistance test to abrupt exposure to higher salinity to ascertain whether benfotiamine renders protection in the catfish fry. The results show that catfish fry subjected to abrupt salinity change from 0 to 10 ppt following feeding with the HCB diet exhibited the lowest cumulative mortality, while those fed the C and HC diets showed higher cumulative mortality. In conclusion, elevating dietary carbohydrates in the diet (i.e., C to HC diet) negatively affected the growth of the African catfish. Further supplementation of benfotiamine to the HC diet at 0.02% enhanced significantly (p