Studies on nutrient digestibilities (pre-caecal and total) in pancreatic duct-ligated pigs and the effects of enzyme substitution

The influence of pancreatic exocrine insufficiency on the digestibility (pr e-caecal and total) and composition of ileal chyme and faeces was quantitat ively investigated in pancreatic duct-ligated mini-pigs char were fed a hig h fat diet with and without enzyme substitution. The studies were performed in six mini-pigs prepared with an ileocaecal re-entrant fistula; in three of the pigs the pancreatic duct was also ligated. Each animal was fed ia ic e daily with 250 g of a high fat (30.1% crude far, 14.9% crude protein, 3.9 % crude fibre, 24.9% starch) diet. During enzyme substitution the animals w ere given 8, 16 or 24 capsules of an enteric-coated pancreatin product (est imated. enzyme content in FID units per capsule: amylase 11200, lipase 1400 0, protease 665). Ileal chyme (chromic oxide as marker) was collected over 12 h(fractionated in 2 h samples) on three different days, while faeces wer e collected in a further period of 5 days to enable determination of total digestibility. Analyses were made of: raw nutrients, starch, sugar, pH valu e, viscosity, lipopolysaccharides (LPS), L-lactate and in some samples vola tile fatty acids and total bacterial counts. Ileal chyme in pancreatic duct ligated pigs showed a significantly higher content of dry matter compared with control pigs; this was normalized when enzymes were substituted. Ileal chyme pH of pancreatic duct-ligated pigs was 0.4 units lower than in contr ols. Among the effects of pancreatic duct ligation on chyme composition the dramatic increase in LPS content (indication of colonization by gram-negat ive bacteria) deserves a special mention. Following enzyme substitution the values returned to normal. In contrast to controls pool pre-caecal nutrien t digestibility was seen in pancreatic duct-ligated pigs, although without pancreatic enzymes it was perhaps surprisingly high. Indeed, digestion of s tarch was scarcely influenced. Hindgut fermentation only partly compensated (apart from fat) for poor pre-caecal digestibility. Pre-caecal digestibili ty was very markedly increased partly dose-dependently, following enzyme ad ministration. Of interest is the observed post-ileal formation of crude far in pancreatic duct-ligated pigs, which is probably caused Ly bacteria. Evi dence for this is che strongly increased faecal content of LPS as well as t he 45-fold increase in faccal E. coil and 15-fold increase in gram negative bacteria. Striking changes were also observed in the fermentation pattern of volatile fatty acids (in faccal water), whereby the proportion of propio nic acid, i-butyric and i-valeric acid as well as n-valeric acid were stron gly increased in faeces of the pancreatic duct-ligated pigs. The high level of metabolizable energy (ME) of the high fat diet determined in the contro l animals [21.5 MJ ME/kg dry matter (DM)] was strongly reduced in pancreati c duct-ligated pigs (12.6 MJ ME/kg DM) and elevated following enzyme substi tution (17.8 MJ ME/kg DM). Although enzyme substitution very markedly impro ved pre-caecal digestibility in pancreatic duct-ligated pigs, the values es timated with the highest enzyme substitution, except for starch, still did not reach those seen in the control pigs.