Good nutrition in aquaculture correlates with better sperm quality and reduced abnormalities in parameters such as sperm count, sperm concentration, and motility (Oke et al. 2019). Some plants have been reported to enhance gonadal development, induce maturation and increase growth in fish species (Oke et al. 2019). These plants contain inherent active ingredients (sterols, flavonoids, saponins) and nutrients for their actions. Clarias gariepinus is a very important freshwater fish in Nigeria that enjoys wide acceptability in most parts of the country because of its ease of cultivation and unique taste, flavour, and texture. World Health Organization encourages the use of medicinal plants to minimize the use of chemicals as fertility enhancers, hence the use of Cocos nucifera in this study. The study aims to determine the dietary effect of C. nucifera on the biochemical composition of milt and the reproductive performance of male C. gariepinus broodstock.
Materials and methods
Sixty male C. gariepinus (446.56 g) were randomly distributed into 15 concrete tanks (1×2×1.5m3) at four fish per tank at the Teaching and Research Farm, Federal University of Technology, Akure . Five isonitrogenous diets at 40% crude protein level with different inclusion levels of C. nucifera powder were formulated (Table 1). The experimental fish were randomly assigned to five treatment groups (n = 3). The fish were fed at 3% biomass daily spread over two rations (0900 and 1400) for 56 days . The fish were batch-weighed bi-weekly and th e water quality was monitored weekly (Temp 26.65±0.02, DO 5.98±0.04, pH 7.85±0.05). At the end of the trial, reproductive indices, hormone level, biochemical indices of milt of the fish, and phytochemical screening of the plant were investigated using standard methods as described by Hussain et al. (2018). The total protein, glucose, cholesterol, calcium, and magnesium of the milt were measured using the spectrophotometric method. The concentration of sodium and magnesium was determined with a flame photometer. Data were analyzed with SPSS v22 using one-way ANOVA.
There were significant differences (P <0.05) in the values obtained for milt volume, milt count, motility duration and weight of testes of C. gariepinus fed C. nucifera endosperm residue (Table 2). Testosterone level, % fertility, hatchability, and survival were highest in fish fed CN1.5. All treatments displayed normal biochemical composition. There was no significant difference (P <0.05) in most analysed biochemical parameters except for magnesium and sodium (Table 3).
The study showed that the inclusion of C. nucifera endosperm powder in the experimental diets improved the milt quality , however it was observed that when C. nucifera inclusion level was above 1. 5g/kg, the weight of the testes and milt volume decreased. The inclusion level of 1.5g/kg gave the best performance for the milt count, % motility, fertility, hatchability, survival, and testosterone level of C. gariepinus.
Hussain S., Balkhi, M. H., Bhat, F. A., Wani, G. B., Tasaduq, H. S. and Bilal, A. B. (2018). Biochemical composition of the seminal plasma of Schizothorax niger in response to different doses of synthetic breeding hormone WOVA-FH . Journal Entomology and Zoology Studies; 6(6): 1033-1037.
Oke , I. S., Dada, A. A. Saliu , O. R. and Kuyoro , E. S. (2019). Dietary effects of Desmodium (Desmodium adscendens) leaves on the reproductive indices in African Catfish ( Clarias gariepinus ) Broodstock . Aquaculture Studies; 19(2): 133-137