EFFECTS OF FEEDING DIFFERENT LEVELS OF COWPEA (VIGNA-UNGUICULATA) ON GUT MORPHOLOGY AND FECAL COMPOSITION IN WEANLING PIGS

The effects of feeding diets containing different levels of raw cowpea on the histomorphometry of the small intestine and faecal composition were investigated in weaned piglets. A total of 100 21-day-old weaner s were divided into five equal groups and were assigned to one of the five following meals; 100% soyabean (T-1); 25% cowpea (T-2); 50% cowpe a (T-3); 75% cowpea (T-4) and 100% cowpea (T-5) There were five pens f or each group and four piglets per pen. The feeding trial lasted 28 da ys. Anti-nutritional factor (ANF) assay of the feeds revealed a higher tannin content in the T-4 and T-5 groups. Live weight gain was lower in the T-5 group, as compared to other groups. Those animals which wer e fed diets T-1 to T-4 had longer villi, larger villus area and greate r villi perimeter than pigs fed T-5 diet. Fresh faeces collected daily for up to seven days postweaning, were analysed for their pH and mois ture content while osmolarity and the levels of electrolytes, glucose and protein were determined from their extracts. The faecal analysis r evealed an increase in the moisture content and a decrease in osmolari ty in the T-1 and T-5 groups. Glucose and electrolyte concentrations w ere highest in the faeces of T-1, T-2 and T-3 animals. A transient and mild diarrhoea was observed in the T-1 group. However, 100% raw cowpe a feeding (T-5) results in pathophysiological changes in gut morpholog y leading to impaired absorption of nutrients. ANFs in the raw cowpeas could account for the observed changes in gut morphology and faecal p arameters. The diminished growth therefore may be due to reduced diges tive and absorptive capacities as a result of intestinal mucosal chang es. It is suggested that processing of cowpeas is essential in additio n to reducing the percentage composition of cowpeas in the pig ration, if they are to be recommended as a suitable alternative to the soyabe ans in stockfeed.