The effect of level and type of cereal non-starch polysaccharides on the performance, nutrient utilization and gut environment of pigs around weaning

The influence of non-starch polysaccharides (NSP) level and solubility on performance, digestion site and gut environment was investigated in 20 Swedish Yorkshire litters between 3 and 9 weeks of age. The litters were distributed among five diets based on cereals and cereal by-products. The control diet (C) had a medium content of NSP (147 g/kg dry matter (DM)), whereas diets H and Hi had a high content of NSP (188–250 g/kg DM), and diets L and Li had a low content of NSP (95–109 g/kg DM) after dilution with starch. The proportion of insoluble (i) NSP was higher in diet Hi and Li (0.80–0.85) than in diets C, H and L (0.68–0.73). The pigs offered diet Li showed the highest (P<0.05) feed intake and grew faster (P<0.05) than pigs offered diets C, L and H. In the post-weaning period feed:gain was highest for pigs offered the C and H diets and lower for pigs offered the low NSP diets and diet Hi. During week 6, the coefficient of caecal (CCAD) and total tract (CTTAD) apparent digestibility of organic matter (OM) was lower (P<0.05) in diet Hi compared to the other diets, and the CCAD and CTTAD of crude protein (CP) was higher (P<0.05) in diet L compared to the high NSP diets. During week 7, the CCAD and CTTAD of OM was lower (P<0.05) in diet Hi compared to the low NSP diets and diet C. The CCAD of CP and starch was higher (P<0.05) in diet L compared to the control diet. Diet L showed higher (P<0.05) values of digestible energy compared to the high NSP diets, both in the 6 and 7 weeks old piglets. NSP solubility influenced (P<0.05) the caecal digestibility of arabonixylans and total NSP in the 6 and 7 weeks old piglets, as well as the caecal digestibility of total dietary fibre in the 7 weeks old piglets. The content of total organic acids (OA) was linearly related to the pH level at the ileum (R2 = 0.70), caecum (R2 = 0.57) and colon (R2 = 0.83). The experimental diets altered the molar proportions of lactic acid and short chain fatty acids (SCFA), of total OA, as well as the molar proportions of acetic, propionic and butyric acids, of total SCFA, in the stomach, ileum, caecum and colon of the piglets. In conclusion, NSP solubility influenced the digestibility of cell wall polysaccharides at the caecum but not at the total tract. Diet Hi promoted production of lactic acid in the stomach and small intestine and butyric acid in the large intestine.