Evaluation of Watermelon (Citrullus lanatus) Juice as a Natural Milt Diluent in the Artificial Propagation of African Catfish (Clarias gariepinus)
Obajulaye, E. O *
Department of Fisheries and Aquaculture Technology, School of Agriculture and Agricultural Technology, The Federal University of Technology, Akure, Ondo State, Nigeria.
Adebayo, O. T
Department of Fisheries and Aquaculture Technology, School of Agriculture and Agricultural Technology, The Federal University of Technology, Akure, Ondo State, Nigeria.
Ojebuola, T.O
Department of Fisheries and Aquaculture Technology, School of Agriculture and Agricultural Technology, The Federal University of Technology, Akure, Ondo State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aims: This study evaluated the qualitative parameters of African catfish (Clarias gariepinus) milt diluted with normal saline and watermelon (Citrullus lanatus) juice at different dilution ratios during induced breeding.
Study Design: Completely randomised design (CRD) with six treatments and three replicates per treatment.
Place and Duration of Study: The Teaching and Research Fish Farm and Limnology Laboratory, Department of Fisheries and Aquaculture Technology, Federal University of Technology, Akure, Ondo State, Nigeria, between October and December 2024.
Methodology: Four apparently healthy broodstock of C. gariepinus (two males, 2.0 kg each; two females, 1.8 kg each) were selected based on maturity indices. Milt was collected from dissected males into dry vials and diluted at different ratios of saline and watermelon juice: 1:0:0 (T1, control), 1:10:0 (T2, reference), 1:7.5:2.5 (T3), 1:5:5 (T4), 1:2.5:7.5 (T5), and 1:0:10 (T6). Sperm quality (motility, motility duration, pH, and concentration), fertilisation, hatchability, egg adhesiveness, and larval survival were evaluated. Data were analysed using one-way ANOVA, and means were separated with Duncan’s multiple range test at a 5% significance level.
Results: Significant differences (p < 0.05) were observed in sperm motility, motility duration, and pH across treatments, while sperm concentration showed no significant variation (p > 0.05). The highest motility percentages were obtained in T4 (56.64%) and T5 (56.94%), compared with the lowest in T1 (24.16%). Fertilisation success ranged from 85.62% in T5 to 91.76% in T4, with T4 also recording the best hatchability (75.89±1.57%) and survival outcomes (75.41±2.57%). Physiochemical parameters of water during the culture period (temperature, dissolved oxygen, and pH) remained within optimal limits for C. gariepinus breeding.
Conclusion: Watermelon juice (Citrullus lanatus) demonstrated strong potential as a natural and cost-effective diluent for milt in artificial propagation of African catfish. The 1:5:5 dilution ratio (milt:saline:watermelon juice) proved most effective, producing optimal sperm motility, fertilisation, hatchability, and larval survival.
Keywords: Citrilus lanatus, milt diluent, saline solution, sperm quality, fertility, hatchability, survival, Clarias gariepinus