EFFECT OF PROBIOTICS ON GROWTH, CARCASS YIELD AND QUALITY CHARACTERISTICS, REPRODUCTIVE PERFORMANCE, HAEMATOLOGY AND SERUM BIOCHEMISTRY OF RABBITS

Abstract

This study was carried out to evaluate the effects of probiotics (Saccharomyces boulardii and Saccharomyces cerevisiae) supplementation on growth, carcass yield and quality characteristics, reproductive performance, haematology and serum biochemistry of rabbits. The study consists of two (2) experiments. Experiment one (1) was for the parent rabbits while their progenies were harvested for experiment two (2). Fourty five heteregenous growing rabbits were used each for experiment T2, T3, T4 and T5 one and two and randomly distributed into five (5) treatment groups (T1,) with each treatment having three (3) replicates and three (3) rabbits per replicate. T1 (control) had no probiotics, while Saccharomyces boulardii was administered orally on the rabbits weekly at 80 x 106 cfu/ml , 60 x 106cfu/ml, 40 x 106cfu/ml and 20 x 106cfu/ml for T2, T3, T4, and T5 respectively. Serial dilution method was used to determine the doses while the Saccharomyces cerevisieawas added to the feed at 0.2g/kg (2 x 108cfu/ml), 0.4g/kg (4 x108cfu/ml), 0.6g/kg(6 x 108cfu/ml), and 0.8g/kg (8 x 108cfu/ml), for T2, T3, T4 and T5 treatment groups for the two experiments, respectively. Blood samples were collected through the ear maginal vein for haematological and serum biochemical evaluation. Data were also collected on body weight, body weight gain, feed intake, feed conversion ratio and nutrient digestibility. At the end of the feeding trial, a total of fifteen (15) rabbits were randomly selected, one from each of the replicates and slaughtered for meat yield and quality characteristics study. Also data were collected on reproductive performance (doe traits, birth traits, weaning traits and testicular morphometric).The results of haematology in experiment one at week one showed no significant (p>0.05) difference in red blood cells (RBCs), Haemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) but white blood cells (WBC) and packed cells volume (PCV) were significantly (p<0.05) affected. However, at week eight, only WBC was significantly (p<0.05) affected. The results for serum biochemistry of experiment one at week one showed significant (p<0.05) difference in total protein, albumin, sodium and chloride but non significant (p>0.05) difference in potassium while at week eight, the result showed no significant (p>0.05) difference in all the serum parameters. In experiment two, the results revealed non significant (p>0.05) difference in all the haematological and serum biochemical parameters both at week one and at eight. The results also revealed non significant (p>0.05) difference in final body weight, total body weight gain, average daily body weight gain, total feed intake, average daily feed intake and feed conversion ratio in both experiment one and two. Apparent nutrient digestibility also showed no significant (P>0.05) difference in dry matter, crude protein, crude fibre, ether extract, ash and nitrogen free extract. No significant (p>0.05) differences in live weight, slaughter weight, carcass length, eviscerated weight, dressing percentage, head, neck, pelts, fore limb, hind leg, ribs and loin were observed in both experiment one and two with the exception of hind leg where it was significantly (p<0.05) affected in experiment two. The viscera organs also showed no significant (p>0.05) difference in all the parameters in both experiment one and two. Furthermore, the proximate composition of rabbits meat in both the experiment one and two were not significantly (p>0.05) affected. The physical properties, the pH, cooking yield, cooking loss and water holding capacity of the meat in experiment one were not significantly (p>0.05) affected but thermal shortening was significantly(p>0.05) affected. Also in experiment two, the cooking yield, cooking loss and water holding capacity were not significantly (>0.05) affected but the pH and thermal shortening were significantly (p<0.05) affected. The reproductive performance of the does, birth and weaning traits showed no significant (p>0.05) difference in both the experiments. The testicular morphometric characteristics also showed no significant (p>0.05) difference in weight of the testes, circumference of the testes, diameter of the testes in experiment one except in experiment two,where volume of the testes revealed significant (p<0.05) difference. It can be concluded that the administration of probiotics (Saccharomyces boulardiiand Saccharomyces cerevisae improved health status, growth performance, rabbits ability to digest fibre and clearly demonstrate their beneficial effects on the reproductive performance of rabbits. The heavier weight (39.04) observed for kittens kindled by rabbits in treatment 4 (40 x 106cfu/ml of S. boulardii + 0.6 g/kg (6 x 108) cfu/ml of S. cerevisiae) underscore the potential of these probiotics to enhance fertility and reproductive outcomes in rabbit.Importantly, the study also confirms that these probiotics do not adversely affect testicular morphometry in male rabbits, suggesting their safety and effectiveness in improving reproductive health. The findings support the integration of probiotics into rabbits feeding practice, offering a promising strategy for optimising reproductive efficiency and productivity.