Effect of α-galactosidase supplementation of cereal-soya-bean-pea diets on the productive performances, digestibility and lower gut fermentation in growing and finishing pigs

An experiment was carried out to study the effect of adding α-galactosidase to the diet on the performance and digestive parameters of growing-finishing pigs. Fifty-four gilts, average body weight (BW) of 43 (s.e. 0.4) kg, were allocated to 18 pens and used in a production experiment divided in two consecutive periods of 28 days each (growing and finishing). In each period gilts were given a diet based on cereals, soya-bean meal and peas, supplemented (Enzyme) or unsupplemented (Control) with 200 units per kg of α-galactosidase. All diets included 2 g Cr2O3 per kg as a digestibility marker. Food intake and body weight were recorded every 2 weeks and faecal samples by pen were collected at the end of each period. Average daily gain (ADG), food : gain ratio and faecal digestibility of dry matter (DM), crude protein (CP) and neutral-detergent fibre (NDF) were calculated. At the end of the production experiment nine gilts from each treatment were selected and given the finishing diet for a further 10 days before being slaughtered. Samples of digesta from the ileum and caecum were collected and Heal digestibility of monosaccharides determined. Short chain volatile fatty acids (SCVFA) and purine bases (PB) in caecal digesia were analysed. The use of α-galactosidase improved the ADG (P < 0.01) and the food : gain ratio (P < 0.01) simultaneous to increases in the faecal digestibility of DM (P < 0.05), CP (P < 0.05; and NDF (P = 0.07) in the finishing period. Alpha-galactosidase supplementation also improved the ileal digestibility of some monosaccharides (galactose, rhamnose, mannose and fucose) of the dietary fibre fraction (P < 0.05); and reduced total caecal concentration of SCVFA (P = 0.15), proportion of branched-chain VFA (P < 0.001), and concentration of total PB (P < 0.001). It is concluded that adding α-galactosidase to a cereal-soya-bean meal-pea diet improves ADG, food : gain ratio and digestibility in fattening pigs, and reduces the amount of fermentable substrate flowing to the large intestine. © 2000 British Society of Animal Science.