Agro-Waste Biochar Conversion into a Fish Feed Additive: Assessing its Effects on the Health and Performance of Cyprinus carpio

Abstract Managing agro-waste effectively and sustainably is a significant challenge today. In this study, various waste-derived biochar (BC) derived from agricultural origins such as cotton, wheat, corn, grass, household and green wastes, were used as supplements in the various fish meal formulation. Cyprinus carpio fishes were fed with the different diets to investigate their effects on growth, nutrient and mineral digestibility, hematology and body composition. A basal diet of sunflower meal was fed for a period of 60 days. Seven experimental diets were prepared, consisting of a control diet and six test diets, each containing 2% of a distinct biochar sources: household waste (HW), cotton stick (CS), green waste (Gw) wheat straw (WS), corn cob (CC), and grass waste (GW). There were 15 fingerlings in each tank; with three replicas of each test diet and they were fed at 5% with respect to the body weight. The findings demonstrated that supplementing with CCBC substantially ( p < 0.05) increased the growth performance, digestibility and carcass of Common carp, C. carpio, while HWBC showed negative results. The highest efficiency in mineral absorption was observed in the test fishes when with the supplementation of 2% corn cob biochar (CCBC) in the diet. Moreover, the fish blood profiles showed significant improvements ( p < 0.05) when fed with CCBC. Conclusively, CCBC was found to be the most effective supplementation for improving growth, hematology, carcass, digestibility, and mineral status of C. carpio .