Growth Performance and Reproduction Control of Oreochromis niloticus Fed Calotropis procera (Giant Milk) Leaf Meal as Fertility Inhibitor

B.J. Akin-Obasola, B.W. Obe, O.O. Ajayi and E.O. Awolusi

Background and Objectives: The early maturation of Oreochromis niloticus results in overpopulation of tanks, poor growth and production rate hence the need to sterilize and control its reproduction for better harvest. The specific objectives of this study were to: assess the nutrient utilization of Oreochromis niloticus fed Calotropis procera leaf meal (CPLM), determine the effect of CPLM diets on the growth performance and reproduction control in Oreochromis niloticus (Nile Tilapia). Materials and Methods: This experiment was lasted for 62 days. Control treatments (T1) and treatments 2, 3, 4 and 5 were prepared adding 0, 6, 12, 18 and 24 g of milled Calotropis procera leaf kg^–1 diets respectively to provide 40% crude protein required by tilapia. Results: The histology of ovary in Oreochromis niloticus fed CPLM diet at different levels revealed that the ovary was filled with developing oocytes at the level of 6 g kg^–1 of diet, predominantly degenerating oocytes at level of 12 g and 18 g kg^–1 of CPLM and alteration in ovary development, consisting of predominantly degenerating oocytes at the highest level (24 g). In the control experiment, the oocytes were separated by the stroma cells and interstitium was free from clustering. The histology of testis in Oreochromis niloticus fed CPLM diet at the level of 6 g kg^–1 of diet showed spermatogenetic series at varying degree of maturation, increase in necrosis at the level of 12 g, great distention and loss of spermatogenic cells within the seminiferous tubules at levels of 18 and 24 g. However, the control treatment showed normal architecture. Histology of liver in Oreochromis niloticus fed CPLM showed infiltration of inflammatory cells at the level of 6 g kg^–1 of diet, loss and degeneration of hepatocytes at the level of 12 g kg ^–1 of CPLM, loss and degeneration of hepatocytes and vascular congestion at the level of 18 g kg^–1 of CPLM and severe loss and degeneration of hepatocytes at the level of 24 g kg^–1 of CPLM. Histology of gills in Oreochromis niloticus fed CPLM diet at different levels revealed degenerative changes which were consistent with autolysis at the level of 6 g kg^–1 of diet, necrosis and degenerative changes revealed at the level of 12 g kg^–1 of diet, inflammatory cell infiltration, hyperplastic epithelia congestion and features suggestive of telangiectasis were revealed at 18 g while necrosis and inflammatory cell infiltration, hyperplastic epithelia (HPE) were revealed at the level of 24 g kg^–1 of diet. However control treatment appeared normal. Conclusion: At the end of the experiment, there were significant differences in growth performance of fish at different treatments used. The best growth response was noticed in treatment 5 where the weight gain, feed conversion ratio and specific growth rate were the best. The results obtained showed that Calotropis procera could be used as anti-fertility agent in controlling Oreochromis niloticus reproduction and its growth performance.

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