INCREASED NITROGEN SECRETION BY INCLUSION OF SOYA LECTIN IN THE DIETSOF PIGS

A study was conducted with 12 castrated male pigs of 13 kg average bod y weight (BW) to investigate the metabolic flow of purified soya lecti n (SL) incorporated in pig diets in low and high doses and their effec t on nitrogen (N) passing the terminal ileum. The pigs were fitted wit h a post-valvular T-caecum cannula and two indwelling blood catheters. They were daily fed 500 g of a corn-starch-based semi-synthetic diet, free or supplemented with low or high doses of purified lectin. To de termine the proportion of endogenous N on the amount of total N passin g the terminal ileum, the N-15-isotope dilution method was used. The a mount of dietary ingested total lectins, determined by an ELISA method , recovered in the stomach was reduced from 177 and 1065 mg kg(-1) of dry matter (DM) to 4.53 and 28.70 mg kg(-1) of DM for the low lectin ( LL) and high lectin (HL) diets, respectively. The concentration of lec tins in mg kg(-1) of DM in stomach and ileal digesta were at a similar level for LL and HL diets. The concentration of functional lectins as determined by the FLIA method (i.e. lectins capable of carbohydrate b inding) were estimated in gastric digesta at 2.51 and 21.52 mg kg(-1) of DM for LL and HL diets, respectively. They could not be detected in ileal digesta. The daily ileal DM and total N flow was significantly increased (P < 0.05) when feeding the HL diet, as compared with the le ctin-free (control) and LL diets. The dietary inclusion of purified le ctin increased (P < 0.05) the daily flow of endogenous N at the termin al ileum. With LL and HL containing diets, the ileal N flow were incre ased to 0.14 and 0.62 g day(-1), respectively, when compared to a cont rol diet. Endogenous N passing the terminal ileum was increased by 0.3 3 and 0.51 g day(-1) for LL and HL diets, respectively. In addition, t he production of volatile fatty acids which appeared in the ileal dige sta, in particular acetate and proprionate was increased in the pigs t hat were fed with the lectin-containing diets.