EFFECT OF USING DIFFERENT LEVELS OF BIOLOGICALLY TREATED RICE STRAW IN GROWING RABBIT DIETS ON GROWTH PERFORMANCE, NUTRIENTS DIGESTIBILITY AND SOME PHYSIOLOGICAL PARAMETERS.

A.S. Abd El-Hakim* ; I.M.E.Shakweer**  and A.A.Azoz***

* Poultry Nutrition Department     **Animal Nutrition Department

***Rabbit Breeding Department

Animal Production Research Institute, Agricultural Research Center, Dokki, Egypt.

           A total number of one  hundred Bauscat rabbits at 7 weeks of  age were assigned into 10 equal treatment groups (10 rabbits of each) to study the effect of partial and completely replacement of clover hay (CH) by rice straw (RS) biologically treated by  bacteria,( B) , fungi (F) and bacteria plus fungi (BF)  in growing rabbit diets on their growth performance, nutrients digestibility coefficients, feeding value, carcass traits, microbial counts, caecum traits and some blood constituents .Three different biological treated rice straw  (B, F, BF) were used, each at three levels in the experimental diets (25, 30 and 35%) to replace 71.4 , 85.7 and 100% of the  clover hay in the control diet, respectively. The results showed that the biological treatments of RS increased its content of crude protein and decreased crude fiber content compared to the untreated one; Rabbits fed control diet (35% of CH) significantly (P<0.05) recorded the highest final body weight , total weight gain and feed intake and best feed conversion values compared to the other groups. Rabbits fed diets contained 25% of BF significantly (P<0.05) recorded the highest nutrients digestibility coefficients compared to the other treatments in term of TDN and DCP. However, rabbits fed diets containing 35% of B recorded the lowest values of TDN and DCP.  The data of carcass characteristics of rabbits fed either 25 or 30% of (B) and (F) and those fed 25% of (BF) showed insignificant differences with those fed control diet. However, groups fed 35% (B), 30 and 35% (F) and 30% (BF) significantly recorded the worst values of dressing percentages compared to the other groups. Rabbits fed control diet significantly (P<0.05) recorded the shortest length of caecum than other groups. Also, caecum pH value of the control group was significantly (P<0.05) lower than the other groups. Data of either total counts of bacteria x104  or cellulolytic bacteria count of rabbits fed 35% (BF) were significantly (P<0.05) higher than those of other groups.

It can be concluded that the biological treatments of rice straw improved the nutrients digestibility coefficients and their feeding values, also revealed that treated rice straw at levels of 25 and 30% can be used to replace 71.4% and 85.7 and up to 100% of CH in growing Bauscat rabbits diets without adverse effect on their growth performance.

Key words: Rice straw, biological treatments, digestibility, growth, bacteria counts, caecum parameters