NEW ADVANCES IN DIGESTIVE PHYSIOLOGY OF RABBITS WITH THE USE OF TROPICAL FORAGE IN CUBA

The objective of this paper was to determine in vivo and in vitro nutrient digestibility of different tropical forage sources for rabbits. Results of four experiments conducted at the Instituto de Ciencia Animal were used. In the in vivo experiments, twenty-four White New Zealand rabbits of 60 days of age and 1.2 kg live weight were allocated in six individual metabolism cages. They were distributed in a completely randomized design into four groups with six replications. The in vitro experiment was conducted with the use of pancreatine-pepsine-chlorohydric method and cecal inoculum for semisynthetic diets. The use of cecal inoculum was compared with the use of in vivo method. There was higher digestibility (P<0.001) of dry matter (DM), neutral detergent fiber (NDF) and greater microbial growth using citrus meals diets with bacterial counts of 68.18, 45.17 and 2.56 x 1010 cfu/g for Medicago sativa, Saccharum officinarum and mulberry, respectively, while no differences in NDF digestibility between these forage sources and the citrus meal were observed. High correlation coefficient (R2=0.71; P<0.05) between in vitro and in vivo NDF digestibility was obtained with the use of cecal rabbit inoculum and mulberry as the substrate. The NDF and ADF digestibilities increased in animals fed with 10 and 20 % of dolicho forage meal. The NDF digestibility improved (P<0.01) by 15.21 and 13.29 % in comparison with the control at 10 and 20 % inclusion, respectively. It can be concluded that the citrus meal has higher nutritional quality than mulberry and sugarcane meal, and that the use of dolicho and mucuna forages at moderate level improves digestibility of diet fiber fractions