DIGESTIBILIDAD ILEAL Y RECTAL DE CERDOS CRIOLLO CUBANO ALIMENTADOS CON DIETAS DE MIELES ENRIQUECIDAS DE CAÑA DE AZUCAR Y AFRECHO DE TRIGO

SUMMARY Two experiments were conducted to know if the process of genetic improvement through selection carried out during 12 years in Cuban Creole pigs had influence if any on nutrient digestibility of non conventional diets, formulated to contain sugar cane molasses, and where wheat bran was introduced as a component rich in cell wall. In experiment 1, four Cuban Creole pig, either improved or not, in the same proportion, castrate males and ileorrectostomized were used. In experiment 2, another eight Cuban Creole pigs, improved or not in the same proportion too, and intact, were used. The experiments were designed as 2 x 2 factorial arrangements in change over, the factors being either the type of breed or diets containing or not wheat bran (20% of diet, in dry basis). There was not significant (P<0.05) genotype x diet interaction in any measurement. Overall, both ileal and rectal DM digestibility was high and typical of pigs given high proportion of enriched sugar cane molasses. There was no effect of genotype on ileal digestibility of nutrients, except for crude fibre, which, although low, was significantly (P<0.01) minor in the improved Cuban Creole pigs. Wheat bran determined a lower ileal digestibility of nutrients, which was significant (P<0.05) for organic matter (79.2 and 75.3%) but not for N (75.7 and 74.8%). Rectal digestibility of nutrients was not significantly influenced by genotype, although was generally higher in all measured indices in the case of the unimproved Cuban Creole pigs. Rectal digestibility of DM, organic matter and crude fibre were significantly lower (0.05>P>0.01) in the diet containing wheat bran, but rectal digestibility of NDF was significantly (P<0.01) higher than in the control diet. The inclusion of 20% wheat bran in the diet had no influence on N digestibility. It appears that the program for genetic improvement of the Cuban Creole pig had not considerable influence on digestive indices of the animals, al least in diets based on sugar cane molasses. The nutritive value of wheat bran such that employed in the present work was rather high for this type of byproduct.