Evaluation of Bromelain as Hormonal Diluent and Egg De-Adhesion Agent During Artificial Propagation of African Catfish, Clarias gariepinus

Abstract

This study evaluated bromelain, a proteolytic enzyme from Ananas comosus, as a hormonal diluent and egg de-adhesion agent in the artificial propagation of Clarias gariepinus, aiming to identify the concentration that enhances reproductive performance, improves de-adhesion efficiency, and maximises hatchery outcomes compared to undiluted ovaprim. The experiment was conducted at the Teaching and Research Fish Farm, Federal University of Technology Akure, Nigeria, using a completely randomized design with five treatments (0%, 25%, 50%, 75% and 100% bromelain concentration) in triplicate. Apparently healthy female and male broodstock with average weight of 1 kg were induced, stripped manually, and monitored for reproductive parameters. Egg samples were incubated in flow-through systems, and data on fecundity, relative fecundity, fertilization rate, de-adhesion percentage, incubation duration, hatchability, and larval survival were analyzed using ANOVA, Tukey HSD, and polynomial regression at 0.05 significance level. Results showed no significant differences in broodstock weight, egg weight, or fecundity across treatments (p>0.05), confirming that bromelain does not impair ovulation or egg production. However, significant improvements were observed in de-adhesion performance, hatchability, incubation period, and larval survival. The 50% bromelain concentration consistently produced the most favourable outcomes, yielding the highest percentage of non-adhesive eggs (96.86%), the highest fertilization rate (94.33%), the shortest incubation duration, the highest hatchability (86.03%), and the greatest larval survival (76.07%), all significantly higher than the control. Polynomial regression further identified an optimal bromelain concentration of approximately 52% for both de-adhesion and hatchability. The findings demonstrate that bromelain is a safe, efficient, and biologically compatible natural enzyme that enhances reproductive success in C. gariepinus, offering an eco-friendly alternative to traditional synthetic or chemical agents. The study concludes that bromelain within the range of 50–52% concentration, can significantly improve hatchery productivity and contribute to sustainable aquaculture through low-cost, biodegradable, and waste-valorised enzyme utilisation.