Digestion in the pig between 7 and 35 d of age

Abstract

1. In two separate experiments, forty-four pigs weaned at 4–5 d of age were fed on diets containing milk or soya-bean protein until slaughtered at 14, 28 or 35 d of age.2. Daily amounts of nitrogen flowing through the stomach and proximal small intestine of pigs were similar with both sources of protein fed.3. Endogenous N flows in the duodenum, jejunum and ileum of pigs given an N-free diet were 22.9, 7.4 and 4.6 g N/kg dry matter (DM) intake. Endogenous N in faeces was 0.970 g N/kg DM intake.4. The apparent and true digestibility of N to the ileum of 28-d-old pigs was 0.86 and 0.92 for the pigs given the milk-protein diets, 0.80 and 0.86 for the pigs given the isolated soya-bean protein (ISP; Promine D) diets and 0.51 and 0.62 for pigs given the soya-bean meal (SBM)-protein diet. These values over the entire gastro-intestinal tract were 0.98 and 1.00 for milk, 0.92 and 0.95 for ISP and 0.82 and 0.85 for SBM.5. The apparent and true digestibility of N to the ileum of 14-d-old pigs given a liquid milk diet was 0.92 and 0.94, while the values for the pigs given a pelleted milk diet were 0.86 and 0.87. At 35 d of age there were no differences in the apparent digestibility of the N in the liquid and pelleted milk diets.6. The apparent digestibility of N to the ileum and over the entire gastro-intestinal tract of pigs given ISP (Supro 610) increased with increasing age of pigs from 0.83 at 14 d of age to 0.88 at 35 d of age.7. Of the N in the stomach 14–32% could not be precipitated by trichloroacetic acid (TCA; 30 g/l).8. In the jejunal and ileal contents an average of 46 and 24% of the N was precipitated by TCA in pigs given soya-bean proteins and milk proteins respectively.