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African Journal of Food, Agriculture, Nutrition and Development

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Screening of leaf meals as feed supplements in the culture of oreochromis niloticus

J.C Nnaji, F.C Okoye, V.O Omeje

Abstract


Three leaf meals, Gliricidia sepium, cassava (Manihot esculenta), and Stylosanthes humilis were screened as feed supplements in the culture of the Nile Tilapia, Oreochromis niloticus. The experiment had four treatments. Treatment A had S. humilis leaf meal incorporated in the feed while treatment B had cassava leaf meal in the feed. Treatment C had Gliricidia leaf meal incorporated in the feed while treatment D was made up of feed formulated without leaf meal (control). Proximate analysis of these leaf meals showed that Cassava leaf meal had the highest crude
protein content (26.3%) followed by Gliricidia leaf meal (22.9%) and Stylosanthes leaf meal (19.5%). All the four diets (A – D) were formulated with maize flour, soybean, fish meal, blood meal and the respective leaf meals and crude protein content ranged from 30.57 – 36.42 %. The diets were distributed randomly to twelve experimental units containing Oreochromis niloticus fingerlings with mean weight range of 2.40-2.55g and fed for twelve weeks. The feed containing cassava leaf meal
(Treatment B) gave the best mean weight gain of 3.50 ± 0.01g followed by the feed with Gliricidia leaf meal with a mean weight gain of 2.21 ± 0.06g while the feed with Stylosanthes leaf meal and the control gave mean weight gains of 2.05 ± 0.25g and 1.06 ± 0.03g, respectively. Mean weight gain in treatment B (cassava leaves) was significantly higher (P<0.05) than mean weight gain in other treatments. Mean growth rate ranged from 0.01 ± 0.006 g/day for the control treatment to 0.04 ± 0.001 for the fish fed Cassava leaf meal diet. Specific growth rate (SGR) was also highest in the treatment with cassava leaf meal (1.07 ± 0.11%/day) and lowest in the control. Protein efficiency ratio (PER) was 0.11 ± 0.004 in Treatment B, 0.07 ± 0.001 in Treatment C, 0.06 ± 0.009 in Treatment A and 0.03 ± 0.001 in the control. The food conversion ratio (FCR) was best with cassava leaf feed (3.71 ± 0.19) followed by Stylosanthes (5.51 ± 0.27), Glyricidia (6.17 ± 0.22) and the control (9.48 ± 0.58). FCR, SGR and PER for treatment B (cassava leaves) were significantly better (P<0.05) than the values for other treatments. Percentage survival ranged from 92% with Stylosanthes to 100% with cassava leaf feed. The study showed that leaf meals can be effectively used in the diet of Oreochromis niloticus.



http://dx.doi.org/10.4314/ajfand.v10i2.53354
AJOL African Journals Online