Differential response of legumes and creep feeding on gut morphology and faecal composition in weanling pigs.

The effects of creep feeding and different levels of soybean meal (SBM) and cowpea meal on the intestinal morphology and faecal characteristics were investigated in weaners. Prior to the feeding trial, one group of piglets was creep-fed and the other noncreep-fed. The two groups of piglets were weaned at 28 days and randomly assigned to four different diets, the main protein sources of which were: T1--skimmed milk power (control); T2--31% soybean meal (high SBM), T3--15% soybean meal and 12% skimmed milk powder (low SBM), and T4--100% raw cowpea meal. Live weight gain was highest in the control group, and least in cowpea-fed piglets. At weaning, only the noncreep-fed weaners showed villus atrophy and crypt hyperplasia but at 7 days postweaning, these changes were evident in all groups except the control and were more severe in the noncreep SBM and cowpea-fed groups. At 21 days postweaning, only noncreep cowpea-fed pigs showed a reduced villus height when compared to the control group. A mild diarrhoea was generally observed in all noncreep-fed weaners, but its onset was more rapid (P < 0.01) and the duration much longer (P < 0.05) in the high SBM and cowpea-fed pigs than in low SBM and control groups. A lower faecal pH was observed in weaners that had diarrhoea when compared with a pH of 7.1 in pigs with normal faecal moisture. The observations of enteropathology and low growth performance in the cowpea group suggest that feeding raw cowpea to weaners may induce antigenicity in the intestinal mucosa, causing damage and a consequent decrease in productivity. However, the introduction of creep feeding before weaning appears to have some ameliorative effects.

Effect of castration on serum concentrations of gonadal hormones, insulin-like growth factor-I and its binding proteins in male pigs.

Ten male pigs (Large White x Landrace), 7 months old, were randomly allocated to two experimental groups. Five of them were castrated and the other five served as controls. Sera were collected on the day of castration and 1, 5, 6 and 7 weeks after castration for hormone assay. There was a significant rise in the splenic and pancreatic weights in the castrates (P < 0.01). The weights of prostate, seminal vesicles and bulbourethral glands were significantly decreased (P < 0.01) in the castrates, which is attributed to a fall in testosterone levels (P < 0.001). The fall in oestradiol concentrations (P < 0.001) in castrates confirms that the testis is the major source of oestrogens in males. Although there was no significant change in the body weight, serum IGF-I levels were elevated in the castrates as compared to the controls after 5, 6 and 7 weeks (P < 0.001). IGFBP bands of 43 and 39 kda predominate in both control and experimental groups indicating that castration had no effect on the IGFBP pattern. It is suggested that the increase in IGF-I levels may be due to uncoupling of GH/IGF-I axis induced by the decrease in steroid concentrations due to castration.

Effects of dietary soybean and cowpea on gut morphology and faecal composition in creep and noncreep-fed pigs.

The effects of creep feeding and different levels of soybean meal (SBM) and cowpea meal on the intestinal morphology and faecal characteristics were investigated in weaners. Prior to the feeding trial, one group of piglets was creep-fed and the other noncreep-fed. The two groups of piglets were weaned at 28 days and randomly assigned to four different diets whose main sources of protein were: T1-skimmed milk powder (control); T2-31 % soybean meal; t(3)-15% soybean meal and 12 % skimmed milk powder; and T(4)-100% raw cowpea meal. Live weight gain was highest in the T1 group, and least in the T(4) group. At weaning only the noncreep-fed weaners showed villus atrophy and crypt hyperplasia, but at 7 days postweaning these changes were evident in all groups except the control and were more severe in the noncreep (T2,T3) and cowpea-fed groups. At 21 days postweaning, only noncreep cowpea-fed pigs showed a reduced villus height when compared to the T1 group. A mild diarrhoea was generally observed in all noncreep-fed weaners but its onset was more rapid (P < 0.01) and the duration longer (P < 0.05) in the T2 and T4 pigs than in T3 and T1 groups. A lower faecal pH was observed in weaners that had diarrhoea when compared with a pH of 7.1 in pigs with normal moisture. The glucose content of the faeces was found to be significantly higher (P<0.05) in the T2 and T4 groups. The observations of enteropathology and low growth performance in the T4 group suggest that feeding raw cowpea to weaners is capable of inducing considerable antigenicity in the intestinal mucosa, causing damage and a consequent decrease in productivity. However, the introduction of creepfeeding before weaning appears to have some ameliorative effects.

Selenium retention in tissues of swine fed carcasses of pigs grown on diets containing sodium selenite or high selenium white sweet clover grown on fly ash.

Growing pigs were fed diets containing 5 or 10% white sweet clover, and 0, 3.5 or 7.0 ppm selenium (Se) supplied as sodium selenite (Na2SeO3) or occurring naturally in white sweet clover harvested from a coal fly ash dump. Ground carcasses of these pigs were included in corn meal diets at 23% and fed back to pigs. Compared to the pigs fed the high Se, fly ash-grown clover diets, the pigs fed Na2SeO3 diets had higher blood Se levels but lower Se concentrations in kidney, liver and skeletal muscle. Tissues of the pigs which were fed carcasses of the high Se clover-fed pigs had higher Se concentrations than those of the pigs fed carcasses of the Na2SeO3 - fed pigs.