Exploitation of Raw, Fermented and Microwave- Heated Rice Bran as Carbohydrate Alternatives in Young Common Carp (Cyprinus carpio L.) Diets

The current study was carried out to investigate the impact of using rice bran (Oryza sativa), raw, treated microbiologically through fermentation with dry yeast Saccharomyces cerevisiae, and thermally using microwaves as a partial substitute for wheat and yellow corn in preparing diets for young common carp (Cyprinus carpio). Four experimental diets were formulated with similar protein and caloric contents. The first diet (C) had no substitution, while the second diet (T1) used untreated rice bran with a substitution rate of 10% for wheat and 5% for yellow corn. The third diet (T2) utilized fermented rice bran with the same substitution rates, and the fourth diet (T3) used thermally treated rice bran with the same substitution rates. Statistical analysis results revealed significant differences (P≤ 0.05) among the various rice bran treatments. The preference was obvious for fish fed on fermented rice bran, followed by the diet containing microwave treated rice bran, then fish fed on the diet containing untreated rice bran, and finally, the control diet. In terms of growth parameters, the feed conversion rate was recorded as 2.75 2.81 2.39 2.65 for each of the diet C, T1, T2, T3, respectively, and digestibility was recorded as 82.22 75.10 83.34 75.10% for each of the diet C, T1, T2, T3, respectively. The study concluded that both fermentation and microwave treatments have improved the nutritional value of rice bran in the diets for young common carp which could be exploited for applying more non-conventional feed ingredients for sustainability of aquaculture.