Fermented fish silage-based cost-effective farm made feed as an alternate to conventional formulated feed for Genetically Improved Farmed Tilapia (Oreochromis niloticus): effects on growth performance, feed utilization, whole-body composition, and economic efficiency

A 45-day feeding trial was conducted to evaluate the effects of farm-made feed (FMF) containing fermented fish silage (FFS) on the growth, production efficiency, and health of Genetically Improved Farmed Tilapia (GIFT) fingerlings (15 ± 0.30 g). The FFS used in the study contained 11.62% crude protein and 3.36% lipid and was a good source of lysine (4.49%), glutamic acid (4.57%), and aspartic acid (3.89%). A conventional formulated feed (CFF, 27% protein and 4.50% lipid) served as the control diet, while three test diets were prepared with FFS at 50%, 60%, and 70% inclusion levels. The experiment was conducted in a completely randomized design using 12 350-L circular FRP tanks, each stocked with 10 fish, with three replicates per treatment. Results indicated that fish fed CFF showed the highest (P < 0.05) weight gain (27 g) and the best feed conversion ratio (FCR, 1.40). Among the FFS-based diets, FFS60 produced significantly better performance (WG, 17.60 g; FCR, 1.66; feed intake, 50.26 g) than FFS50 and FFS70. The FFS70 group showed reduced growth and a higher FCR compared to the other FFS-fed groups. Whole body proximate composition varied significantly (P < 0.05) among treatments for crude protein, crude lipid, total ash, and nitrogen-free extract. Economic analysis revealed that the FFS60 diet achieved the lowest feed cost per kg weight gain (₹63.53). Overall, FFS60 demonstrated an optimal balance between growth performance and affordability, indicating that a 60% inclusion level of FFS in farm-made feeds is a cost-effective alternative to costly commercial feeds.