Effect of mannan oligosaccharides on the ileal morphometry and cecal fermentation of growing rabbits

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A common problem in rabbits is the occurrence of digestive disorders just after weaning. This problem is usually associated with instability of the cecal microflora and characterized by diarrhea, loss of appetite and increased mortality. In the current study the effects of a mannan oligosaccharide (MOS, Bio-MOS ® , Alltech Inc. USA) was compared to a commonly used antibiotic (AGP, Zn-Bacitracin). The current study investigated the effects of MOS and AGP on intestinal morphometry and cecal VFA production. A total of 220 weaned mixed-sex rabbits (32d) were divided into 5 experimental treatments and housed in groups of 4 in 55 flat deck cages located in an experimental rabbit house. The 5 experimental treatments were as follow: Control (no additives);MOS 1 (1 kg MOS/t); MOS 1.5 (1.5 kg MOS/t); MOS 2 (2 kg MOS/t) and AGP (0.1 kg/t). Experimental diets were based on alfalfa, sunflower meal and wheat and beet pulp and were offered ad libitum through out the experiment. Intestinal morphology and cecal fermentation was determined in 8 rabbits per treatment slaughtered at day 46. Histologic examination showed significantly longer villi (P<0.05) in rabbits fed MOS (503.1, 518.6 and 508.8 for MOS 1, MOS 1.5 and MOS 2, respectively) or AGP (502.5) compared to the control group (403.0). This was also translated into a numerically increased absorption surface. Cecal volatile fatty acid (VFA) concentration differed significantly (P<0.05) between treatments. Rabbits fed MOS at 1 kg/t had the highest total VFA concentration (98.02 vs. 51.57 in MOS 1 and Control) and higher butyric acid (14.09 vs. 4.59 in MOS 1 and Control). Furthermore cecal pH was significantly lower in rabbits fed MOS at 1 kg/t and 2 kg/t (5.79 and 5.92) compared to the control (6.33). Results for this study suggest that MOS has a stimulating effect on villi development and production of cecal VFA and reduce cecal pH, which could improve the health status of growing rabbits.
Rabbit , Mannan oligosaccharide , Villi length , VFA