Ileal and rectal digestibility of nutrients in diets based on Leucaena (Leucaena leucocephala (Lam.) de Wit) for pigs.: Influence of the inclusion of zeolite

A change over design was used to study in two experiments the effect of inclusion of a Cuban natural zeolite (5%) in a soybean/grain meal formulated to contain 20% leucaena (Leucaena leucocephala (Lam) de Wit) meal. Responses criteria were apparent ileal and rectal digestibility and N balance indices in 6 Yorkshire x Landrace castrate male pigs each weighing on average 50 kg of initial live weight. In experiment 1, inclusion of 5% zeolite in the diet, determined a decrease in rectal digestibility of organic matter from 83.3-77.4% (p<0.10) and from 78.3-72.4% (p<0.05), respectively. In experiment 2, ileal digestibility of energy and N increased (p<0.05) respectively when 5% zeolite was added to the diet. Faecal concentration of total short chain fatty acids and ammonia were significantly (p<0.05) higher in pigs fed tire diet containing zeolite (103 and 30 mmol/100 g DM) than when the animals were given the control feed (85 and 20 mmol/100 g DM) indicating a net capture of these metabolites by zeolite. In intact animals, a trend for retention of N to be higher in the diet with zeolite than in the other with no zeolite (48.4 and 47.0% of N intake) was noted. It is suggested that the inclusion of 5% of a Cuban natural zeolite in the diet is beneficial for digestive processes in the pig when this animal species is fed tree foliage as leucaena leaves. The incorporation of zeolite to this type of diet could influence pig digestive processes in a positive manner, probably in N economy. Other trials could be conducted to fix the optimal level of inclusion of zeolite in this type of diets.