EFFECT OF MASHED LIME FRUIT JUICE AS AN ALTERNATIVE TO ANTIBIOTICS ON GROWTH PERFORMANCE, VILLI MORPHOMETRY AND CAECAL MICROFLORA OF GROWING RABBITS
Keywords:Antibiotics, Organic acids, Lime, Villi morphometry, caecal microflora.
The experiment was conducted with thirty clinically healthy mixed breed growing male rabbits with average age of 11 weeks old. The rabbits were assigned to six dietary treatments (0, 500, 1000, 1500 2000 ml mashed lime fruit juice (MLFJ) per 100kg feed and Oxytetracycline; Oxyt) in completely randomized design. A basal diet formulated was designated as 0; to which 500, 1000, 1500 and 2000 ml of mashed lime fruit juice per 100kg feed was added to form treatments 500 - 2000 respectively while for Oxyt treatment, 55 g/100kg Oxytetracycline was added to the basal diet as recommended by the manufacturer. Treatments 0 MLFJ and Oxyt served as negative and positive controls respectively. Five growing rabbits were assigned to each dietary treatment and each rabbit served as a replicate. Parameters measured were acidity level, growth performance, villi morphometry and caecal bacterial cell numbers. The trial lasted for 56 days. The results showed lime fruit juice contained 0.6% ascorbic and 8.02% citric acids. Growth performance results showed improvement in final body weight being significantly (P<0.05) higher on 1000 ml MLFJ than other treatments except 500 ml MLFJ and Oxyt treatments. Feed intake and feed conversion ratio of MLFJ groups was comparable to the controls. Feed cost per kg gain was better on the Oxyt and 1000 ml MLFJ groups and worst on 1500 and 2000 ml MLFJ groups. There was significant (P<0.05) differences in all villi morphometric parameters measured except villi width. Villi surface area was significantly (P<0.05) lower on 1000 ml but similar to 500 and 1500 ml MLFJ than the other treatments Villi perimeter and Villi height were significantly (P<0.05) higher on 1500 and 2000 ml than 500 and 1000 ml MLFJ groups but similar to 0 ml MLFJ and Oxyt groups. Crypt depth was significantly (P<0.05) higher on 1500 ml and Oxyt than all others treatment groups. Villi height/crypt depth ratio was significantly (P<0.05) higher on 2000 ml than 1000, 1500 ml MLFJ and Oxyt groups. The population of lactobacilli and Bacilli spp increased as MLFJ increased with the highest value (10.67 and 13.97 x106 CFU/ml) for rabbits fed 1000 ml dietary MLFJ while those of E. coli, Clostridium and Staphylococci spp decreased as MLFJ increased. Results showed that rabbits could tolerate dietary mashed lime fruits juice up to 2000 ml/100kg without negatively affecting feed intake, weight gain, villi morphometric and caecal microflora. However, at 1500 and 2000 ml MLFJ, FC/kg G was increased which had a diminishing effect on the gross margin. It is therefore recommended that mashed lime fruit juice could be included in the diets of growing rabbits at 1000 ml/100kg feed.