Apparent digestibility coefficient of inclusion levels of Zophobas moriolarvae meal for Nile tilapia fingerling

Abstract

Nile tilapia is the most produced fish species in Brazil, being responsible for over 58% of the country's fish farming and almost 36% of the aquaculture production in 2017. Soybean meal is one of the most important protein sources in fish diet, however, it has antinutritional compounds, amino acid deficiencies and can affect fish intestine's integrity and nutrient absorption and digestibility so studies are being made trying to find an alternative protein source for fish diets. Insect are being studied in this regard because of their protein quality and quantity, as well as their sustainability. Zophobas morio protein content varies between 40 and 68%, therefore our goal was to study the apparent digestibility coefficient for diets with inclusion of Zophobas moriolarvae meal in levels in substitution of soybean meal to find out if this insect can be used in Nile tilapia feed. The goal of this research was to determine the nutrient's apparent digestibility coefficient for diets with Zophobas morio larvae meal in Nile tilapia fingerlings.900 Nile tilapia fingerlings were distributed in a completely randomized design in 18 digestibility tanks; fed twice a day with one of the three experimental diets: control, with 0% inclusion of Zophobas morio larvae meal; 15% inclusion or 30% inclusion. 0.5% chromic oxide was added as a marker in those diets. Fish feces were collected for 15 days, dried and then analyzed for centesimal composition and chromic oxide composition. Then, the calculations for apparent digestibility coefficient were made based on the metodology proposed by Nose (1960) and Cho et al. (1985). A total substition of soybean meal for 30% Zophobas morio meal in diets for tilapia fingerlings did not affect the apparent digestibility coefficient when compared to a conventional diet (control diet); the inclusion of 15% Zophobas morio meal increased the apparent digestibility coefficient when compared with the control diet.