Potentials of Dietary Betaine Additives in Reduction of the Cost of Production and Improving Nutrient Content of Oreochromis niloticus (Linnaeus, 1788)

Abstract

This study investigated the effects of graded levels of dietary betaine supplementation (0.0, 0.25, 0.50, 0.75 and 1.0 g/100g feed) on growth performance, nutrient utilization, carcass composition, and feed cost-effectiveness of Nile tilapia (Oreochromis niloticus) fingerlings over a 12-week feeding trial. Three hundred fingerlings with a mean initial weight of 8.00±0.00g were randomly distributed into five treatment groups (BT0–BT4) in triplicate at 20 fish per 300-litre tank. Fish were fed isonitrogenous and isocaloric diets containing 40% crude protein, twice daily at 5% body weight. Results showed that betaine supplementation at 0.50 g/100g (BT2) significantly (P<0.05) improved mean weight gain (44.63g), specific growth rate (2.91%/day), feed conversion ratio (1.72 g/g), protein efficiency ratio (2.31 g/g), and apparent net protein utilization (55.8%). Fish fed BT2 also exhibited the highest carcass crude protein (19.1%) and lowest carcass lipid (4.2%), indicating enhanced protein deposition. Water quality parameters remained within acceptable ranges across all treatments. Cost analysis revealed that BT2 yielded the most economically favourable production cost per kilogram of fish gain. These findings confirm that betaine at 0.50 g/100g is the optimal inclusion level for cost-effective and nutritionally superior production of Nile tilapia, with significant implications for food security in Nigeria.