A comparative evaluation of ileo-rectal anastomosis techniques for the measurement of apparent precaecal digestibilities of folate, niacin and pantothenic acid

In this study two techniques of ileo-rectal anastomosis were compared for their use as a valuable measure of apparent precaecal digestibility of the B-vitamins folate, niacin and pantothenic acid. For that purpose three female pigs were each provided surgically with an end-to-side ileo-rectal anastomosis and five female pigs were fitted with an end-to-end ileo-rectal anastomosis, both techniques with preservation of the ileo-caecal valve (ESV vs EEV). After surgery, the pigs were allowed a 3-week recuperation period before starting the digestibility trial. For the measure of vitamin digestibility the animals received 1.5 kg/day of a fresh wheat diet (62% wheat) with defined amounts of native folate, niacin and pantothenic acid, and digestibility was recorded from week 4 to week 9 and week 12 to week 17 after surgery. Each animal was fed the experimental diet for 12 days, and digesta were collected twice daily quantitatively for the final 5 days. Folate, niacin and pantothenic acid in food and excreta were determined microbiologically. At week 17 after surgery, under conditions of restricted energy intake, growth response and feed efficacy of all animals were within normal limits. Surgical procedure effect was significant for all the apparent precaecal digestibilities of the B-vitamins measured, in which the vitamin concentrations excreted via the chyme were distinctly higher in animals fitted with the ESV than in animals fitted with the EEV, indicating that the ESV procedure may permit some bacterial fermentation to take place. Moreover, the findings revealed no significant difference in apparent vitamin digestibility between the two time periods over which the wheat diet was given. Finally, it was concluded that ESV models do not provide correct digestibility values due to digesta back flow and microbial growth, but the enteric modification of an EEV model has been shown to be a valuable measure in determining the apparent digestibility of vitamins from foods and foodstuffs.