Effects of cowpea (Vigna Unguiculata) feeding on the pancreatic exocrine secretion of pigs

Twenty 5-week-old piglets were weaned onto two different diets. Group 1 was fed soybean-based (T1) and group 2 was fed raw cowpea-based (T2) diets for 3 weeks, The average daily weight gain was significantly lower in the T2 g roup compared with the T1 group (p < 0.05). An analysis of anti-nutritional factors showed that trypsin inhibitor activity, tannins and phenolics were higher in the T2 diet, whereas the lectins were higher in the T1 diet. At the end of the feeding trial, piglets from each group were surgically prepa red with a pancreatic duodenal fistula for chronic pancreatic juice collect ion. In the pancreatic secretions of the T2 group, both the volume and prot eins were decreased (p < 0.04), while trypsin content was elevated (p < 0.0 001). Both bicarbonate and pCO(2) were higher (p < 0.001), whereas the chlo ride levels were lower in the T2 group (p < 0.0001). It is suggested that t he high trypsin inhibitor activity in the raw cowpea-based diets cause grow th inhibition Ly inhibiting trypsin activity, which eventually led to highe r trypsin activity in the pancreatic juice of the raw cowpea-fed Figs. The lower chloride concentration concomittant with the higher bicarbonate conce ntration in the pancreatic juice of raw coa pea-fed pigs, indicates that fe eding with raw cowpea may also have a stimulatory effect on the centro-acin ar cells in the pancreas. This may also be due to a stimulatory effect on t he secretion of bicarbonate and an inhibitory effect on the bicarbonate-chl oride exchange mechanism in the extra lobular ducts in the pancreas. Both n eural and humoral factors may mediate these effects, however, the identity of which remains a matter of speculation.