Effects of vitamin E on growth and reproductive performance of pindani (Pseudotropheus socolofi Johnson, 1974)

Abstract

With the multibillion dollar worth global market, ornamental fish trade provides important business opportunities to aquaculturist. Pindani (Pseudotropheus socolofi) is one of the most popular freshwater fish species that is cultured for this market. However, we know little about its' nutrition and its' culture suffers from low egg and fry production numbers. Among many different nutritional components, essential vitamins, such as vitamin E, could have important impacts on reproductive performance of fishes. In this study, the effects of different dietary vitamin E levels on growth and reproductive performance of pindani were evaluated through two consecutive experiments, encompassing both juvenile and adult stages. Three different levels of alpha-tocopherol were incorporated into a commercially formulated diet at the rate of 50, 100 and 150 mg/kg. Control diet contained 121.3 mg alpha-tocopherol/kg. Elevating dietary a-tocopherol level above 121.3 mg/kg did not improve growth or feed utilization values of juvenile or adult pindani. However, reproductive performance of pindani was significantly (P < .05) lower at this dietary alpha-tocopherol level. The diet supplemented with 100 mg more alpha-tocopherol/kg significantly (P < .05) improved all reproductive indices, including pre and post larval survival rates. Furthermore, this dietary alpha-tocopherol level supported the best possible growth in actively spawning adult pindani. Whereas elevating alpha-tocopherol content of the control diet > 100 mg/kg provided no further improvement, but significantly reduced the relative fecundity of females. These results of the study were discussed in relation to dietary PUFA level, degree of parental care and alpha-tocopherol usage and regeneration balance. At the end, we concluded that a dietary alpha-tocopherol supplementation level of 219.3 mg/kg in a diet with 9% total lipid and 22.5-24.3% PUFA content could substantially improve the breeding performance of pindani and production efficiency of their culture.