Biochar as a Dietary Growth Promoter in Nile Tilapia

Abstract

Biochar is a carbon-rich material produced through pyrolysis of biomass under low-oxygen conditions. The present study evaluated the effect of dietary biochar supplementation on growth performance, feed efficiency and survival of Nile tilapia (Oreochromis niloticus) fingerlings over a 60-day feeding period. Biochar was prepared from the stems of Napier grass (Pennisetum purpureum), charota (Cassia tora), gajar ghas (Parthenium hysterophorus) and babool (Acacia nilotica). Experimental diets were prepared by supplementing a commercial diet containing 24% crude protein with biochar at 2 mg and 5 mg levels, while the control diet contained no biochar. Growth was assessed using initial body weight, final body weight, weight gain, percentage weight gain, specific growth rate and survival rate. Feed utilisation was evaluated using feed conversion ratio, protein efficiency ratio and feed efficiency ratio. Among all treatments, the diet containing 5 mg Parthenium hysterophorus biochar produced the highest final body weight (28.751 g), weight gain (3.976 g), percentage weight gain (16.05%) and specific growth rate (0.25). This treatment also produced the best feed conversion ratio (3.94), protein efficiency ratio (1.06) and feed efficiency ratio (0.25), with 100% survival. The control group recorded a weight gain of 2.67 g, percentage weight gain of 10.76%, specific growth rate of 0.17 and survival of 96%. Overall, biochar-supplemented diets, particularly at the 5 mg level, improved growth and feed efficiency compared with the control. The findings indicate that plant-derived biochar may serve as a dietary growth-promoting additive for Nile tilapia fingerlings under the conditions of this study. This response was achieved without reducing survival in the best-performing treatment.