Substitution of Balanced Feed with Chaya, Cnidoscolus chayamansa , Leaf in Tilapia Culture: A Bioeconomic Evaluation

The main challenge for tilapia culture in rural areas of Mexico is low producer income and difficulty in acquiring inputs (fingerlings and balanced feed). In response, some rural producers feed tilapia with locally available vegetal inputs such as chaya, Cnidoscolus chayamansa . This plant is a bush endemic to the Yucatan Peninsula, Mexico, that is traditionally used for human and animal nutrition. In these rural culture systems, chaya is provided ad libitum as fresh leaves. Its use to date is empirical, and therefore, little is known about optimum substitution levels. A bioeconomic model was developed using experimental data. The von Bertalanffy model was parameterized using chaya/balanced feed combinations that produced growth not statistically different than a diet with sole use of balanced feed. This model included biological, economic, and management components. The results indicate that balanced feed can be substituted by chaya leaves at up to 50% and that this substitution level provides the lowest production costs during the warm season. Maintenance of this production level requires 2.23 units of chaya per unit of balanced feed, with the restriction that only 50% of the ration can be substituted by chaya leaves.