Evaluation of the Digestibility of Diets Containing Soy Okara in Clarias gariepinus (Burchell, 1822) Fries Raised in a Controlled Environment in Benin

Aims: To evaluate the digestibility of diets containing soy okara in Clarias gariepinus fries.

Study Design: Random complete block design.

Place and Duration of Study: Laboratory of Hydrology and Wetland Research, Faculty of Sciences and technics, University of Abomey-calavi, between June 2019 and July 2019.

Methodology: Four diets containing different levels of soy okara (0%, 10%, 20% and 30%) respectively noted T0, T1, T2 and T3 were tested. Twelve 40L tanks were randomly distributed into 04 batches with 03 repetitions for each of the 04 diets. The fries with an initial average weight of 10.47 +/- 2g were fed ad libitum three times a day (8 A.M., 12 P.M., 4 P.M.) for 30 days. Survival rate, cannibalism rate, average daily gain, specific growth rate, weight-length relationship, condition factor, consumption index, ingested protein, protein efficiency coefficient and digestive utilization coefficients were measured.

Results: The specific growth rates (SGR) ranged between 2.25 +/- 0.165 and 2.58 +/- 0.115 with the best rate for the treatment containing 0% soy okara. The consumption index varied from 1.18 +/- 0.009 to 1.41 +/- 0.132 with the best index for the T3 treatment. Furthermore, the mortality rates were 0% for treatments containing 20% and 30% soy okara. The results indicate that it is possible to incorporate up to 30% soybean okara into the diet of Clarias gariepinus fry without hindering their zootechnical performance. The digestive protein utilization coefficients of the diets were calculated and are 95.12; 88.47; 92.21 and 90.37 for diets containing 0%, 10%, 20% and 30% soy okara respectively.

Conclusion: The results demonstrate that among the different diets tested, treatment T2, containing 20% soy okara, proved to be the most favorable in terms of zootechnical performance. These results suggest that T2 treatment can be considered as a promising option for feeding Clarias gariepinus fries.