Comparative Analysis of Sinking Time Index and Water Stability of Different Inclusion Level of Cassava Flour and Brewer Yeast in a Test Diet

: The ability of fish feed to maintain its nutritional content for considerable period of time in pond water has become an important aspect of aquaculture. Several feed binder, mostly starch with other ingredient capable of creating air trap within the pellet of formulated feed has been used to improve the integrity of fish feed in water. The presence of the above characteristics in cassava flour and brewer yeast inform their selection for this experiment. This research, therefore, compares the effect of different percentage inclusion of cassava flour and brewer yeast on fish feed stability and sinking time index of a test diet. Pearson square method was used to formulate a 40% crude protein diet using fish meal, soyabean meal, groundnut cake, rice bran, maize and brewer dry grain. Cassava and yeast were included at 5, 10, 15, 20 and 25% level and represented as C1, C2, C3, C4, C5 for cassava and Y5, Y4, Y3, Y2 and Y1 for yeast, respectively. The treatments were represented as C1Y5, C2Y4, C3Y3, C4Y2, C5Y1. Floatation tests and water stability test were conducted to determine floatation and the level of disintegration of the test diet per time, respectively. All data were analyzed using Analysis of Variance (ANOVA) followed by Fisher’s Least Square Difference (LSD) at 5% level of significance. The result of the experiment revealed significant different across the floatability of the test diet. The diet (C1Y5) had the best floating time index while the diet (C5Y1) had the least floatability performance. Water Stability shows diet (C5Y1) gave the best water stability percentage while (C1Y5) gave the least water stability percentage. The result of the experiment shows that brewer yeast is a very good floating agent and can support floatation of feed in water for more than 25 min, while cassava flour has shown itself as a capable candidate for prolonging the stability of aqua feed in water. Further research can be conducted in the direction that will determine the percentage inclusion of a floating agent and a binder for maximum result of floatation and water stability determination.