FORAGES IN DIETS FOR GROWING PIGS 1 - NUTRIENT APPARENT DIGESTIBILITIES AND PARTITION OF NUTRIENT DIGESTION IN BARLEY-BASED DIETS INCLUDINGLUCERNE AND WHITE-CLOVER MEAL

The present study was undertaken to determine the ileal and total trac t apparent digestibility and hindgut disappearance of dietary componen ts and energy in a barley-based diet which included either lucerne or white-clover meal (proportionately 0.10 and 0.20). The experiment was conducted as a 5 x 5 change-over design with growing pigs fitted with simple t-shaped cannulas posterior to the ileo-caecal valve. The ileal and total tract apparent digestibilities of organic matter (OM), crud e protein, crude fat, nitrogen-free extractives and energy were signif icantly reduced with increasing inclusion of lucerne and while-clover meal in the diet (P < 0.05). The total tract apparent digestibility of total fibre (TF) was significantly reduced with lucerne meal inclusio n (P < 0.05), while the ileal apparent digestibility of TF was unaffec ted by lucerne and white-clover meal inclusion. Hindgut apparent diges tibility (proportion of total tract apparent digestibility) of OM and energy was approximately 0.10, 0.70 and 0.70 for barley, lucerne and w hite-clover meal, respectively. Both the ileal and total tract apparen t digestibility of OM and energy were significantly higher for the con trol diet compared with lucerne and white-clover meal (P < 0.05). Ther e was also a significantly higher apparent digestibility of OM, TF, cr ude fibre and energy in the total tract for white-clover meal compared with lucerne meal (P < 0.05). For neutral- and acid-detergent fibre a similar pattern tons observed, however the effect was not significant . The dietary digestible energy content was significantly reduced (P < 0.05), both at the ileum and over the total tract, with increasing in clusion of forage meal.