Use of Herbal Extracts for Controlling Reproduction in Tilapia Culture: Trends and Prospects - a Review

Abstract

The use of synthetic chemicals in the production of food for human consumption has been condemned by many nations, due to their potential health and environmental hazards. In tilapia farming in particular, synthetic sex reversal hormones have been commonly used to produce all male tilapia progenies. Recently, several herbal extracts have been reported to possess estrogenic properties, some of which are capable of inducing antifertility, abortifacient, and sex inversion in animals. Hence, herbal extracts could be used as safe alternative agents to control precocious tilapia maturity and prolific breeding in production systems. Dietary Basella alba, Quillaja saponaria, Trigonella foenum-graecum, Glycine max and Tribulus terrestris extracts have been reported to shift tilapia sex ratio in favor of males. Moreover, Moringa oleifera, Carica papaya, Aloe vera, Azadirachta indica, and Hibiscus rosasinesis extracts demonstrated a direct effect on gonad morphology and delayed maturation in some tilapia species. However, there are limitations, which make it hard for this novel development to progress from experimental trials to widespread adoption by farmers because of lack of adequate knowledge on phytoestrogen extraction methods, their extract concentrations, and identification methods. Hence, there is a need for more research to standardize every aspect concerning the use of phytoestrogens in tilapia culture. The aim of this paper is to provide an overview of the available studies on the use of herbal extracts as potential alternatives to control tilapia reproduction in aquaculture, while also discussing limitations in the existing knowledge and finding a way forward.