Effect of inulin and mannan-oligosaccharides compared with zinc-bacitracin on growing performance, nutrient digestibility and hematological profiles of growing rabbits

The study aimed to evaluate the effect of inulin and mannan-oligosaccharides (MOS) vs zinc-bacitracin (ZnB) on rabbit growth performance, nutrient digestibility, and blood profiles. In total, 108 rabbits 32 days of age were divided into four homogeneous groups fed the same basal diet and submitted to the following dietary treatments: control group, without supplementation; inulin group, supplemented with inulin (0.25 g/rabbit. day); MOS group, supplemented with MOS (0.083 g/rabbit. day); and ZnB group, supplemented with ZnB (0.083 g/rabbit. day). The supplements were administered 2 days per week from 32 to 81 days of age. At 32, 56 and 81 days, the rabbits were weighed and feed intake was measured. Mortality was recorded daily. Nutrient digestibility was measured at 65 days by an ingesta-excreta balance. Samples of blood were collected at 53, 67 and 81 days of age. The control group showed the highest (P < 0.01) mortality rate throughout the trial (17.0%), followed by ZnB (8.18%), inulin (3.7%) and then theMOSgroup, which had the lowest mortality (1.6%; P < 0.01). Addition of MOS led to a more favourable (P < 0.05) feed conversion ratio than addition of ZnB at 32-56 days of age and inulin for the entire trial period. The MOS group showed increased (P < 0.01) digestibility of dry matter, organic matter, ash and crude fibre relative to the control group. All supplements increased (P < 0.01) protein digestibility relative to the control. The level of alanine aminotransferase was reduced due to the use of feed supplements, and MOS supplementation gave the lowest (P < 0.01) value. Administration of prebiotics to growing rabbits as an alternative to ZnB can lead some advantages compared with both antibiotic and unsupplemented diets; MOS was more effective than inulin.