Supplementary feeding standards of pelleted feed for Nile tilapia (Oreochromis niloticus)
1992
Dhali, Abdur Rashid
Two experiments were carried out in 200 square m static water earthen ponds to evaluate the value of supplementary feed and assess to economic benefit for Nile tilapia (Oreochromis niloticus) with fish of 25 and 100 g fishes. Thirty six hapas were set up in 3 ponds at stocking density 2, 4, 6, 8, 10 and 12 fish/square m with and without feeding treatment. Ponds were fertilized with chemical fertilizers, urea (0.4 gram/square m/day) and triple super phosphate (0.2 gram/square m/day). Fish in the feeding treatment were given pelleted feed, (20 % protein) ad libitum, twice daily. Net yield per (5 square m) hapa per month increased and individual body weight decreased with stocking densities. Individual body weight of supplementary feeding fishes was higher than non fed treatments. Highest extrapolated yields was 98.7 and 49.3 ton/hectare/year at a density 12 fish/square m in feeding and non feeding treatments respectively. Food conversion ratio (FCR) decreased with stocking density. Lowest FCR was 1.55 in large fishes with stocking density 12/fish/square m. Average survival rate was 95 % but the survival rate was higher in small fishes. Feeding standards for small and large fishes were analysed by regression. Net yield (g/hapa) had linear relation with feed intake (g/hapa). Feeding standards involved several factors such as natural food, supplemental feed and water quality. So, feeding standard will be applicable in similar condition. All treatments of without supplementary feeding were profitable but treatments at 12 fish/square m gave the highest net yield and income. Supplementary feed was profitable in large fishes (100-200 g) in at high density 6 fish/square m but high density (12 fish/square m) was the most economic (5635 $/ha/year).
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