Effect of Formulated Feeds with Different Nutrient Levels on Growth and Reproductive Performance of Molly, Poecilia sphenops (Valenciennes)

Molly fish (Poecilia sphenops) were reared for 100 days under four dietary treatments (D1 to D4) with varying crude protein levels. Experimental diets (D1, D2, D3 and D4) were formulated from locally available feed ingredients having crude protein percentage of 25.5, 26.35, 27.8 and 28.8, respectively. Effect of the four diets was studied in terms of growth and reproductive performance based on growth parameters, gonadal development and fry production. Fish fed diet D4 with highest protein level resulted in significantly (P< 0.05) higher final weight, weight gain and specific growth rate (1.29 +/- 0.01%, 1.74 +/- 0.02%, 1.88 +/- 0.04% and 2.10 +/- 0.02% in treatment D1, D2, D3 and D4, respectively) along with significantly (P< 0.05) lower FCR (2.60 +/- 0.02, 2.14 +/- 0.02, 1.98 +/- 0.03 and 1.62 +/- 0.02 in treatment D1, D2, D3 and D4, respectively). The ovary weight, ovary volume, absolute fecundity and mean gonadosomatic index (154.57 +/- 9.85, 159.69 +/- 5.47, 174.38 +/- 2.42 and 212.15 +/- 9.58% in treatment D1, D2, D3 and D4, respectively) of molly fed on the diet D4 were significantly (P< 0.05) higher in comparison to D1, D2 and D3. The number of fry produced (49.39 +/- 0.59, 68.04 +/- 0.29, 74.90 +/- 0.87 and 108.12 +/- 1.16 in treatment D1, D2, D3 and D4, respectively) and their survival (83.69 +/- 0.61, 84.85 +/- 0.63, 88.69 +/- 0.49 and 93.38 +/- 0.53 in treatment D1, D2, D3 and D4, respectively) were also significantly (P< 0.05) higher in fish fed D4 compared to other three diets. Hence, it can be concluded that 28.8% protein is adequate for growth and reproductive performance of molly.