Effects of the Ratio of Insoluble Fiber to Soluble Fiber in Gestation Diets on Sow Performance and Offspring Intestinal Development

To investigate the effects of the ratio of insoluble fiber to soluble fiber (ISF:SF) on sow performance and piglet intestinal development, we randomly assigned 64 gilts to four treatments comprising diets with the same level of dietary fiber, but different ISF:SF values of 3.89 (T1), 5.59 (T2), 9.12 (T3), and 12.81 (T4). At birth and weaning, six piglets per treatment at each phase were slaughtered for sampling. As ISF:SF increased, the mean piglet body weight (BW) at weaning and piglet BW gain, which were all significantly higher in T1 and T2 compared with T3 and T4 (p < 0.05), showed a linear decrease (p < 0.05); the crypt depth of the jejunum in weaned piglets linearly increased, whereas the duodenal weight, jejunal villus height, and villus height/crypt depth in newborn piglets and enzymatic activity of lactase, sucrase, and maltase linearly decreased (p < 0.05). No differences were observed in the yield and composition of milk (p > 0.05). Moreover, when the ISF:SF was 3.89 in gestation diets, higher piglet BW at weaning occurred, possibly because the ISF:SF affected development and enzymatic activity in the small intestine—effects related to digestion and absorption of nutrients—and consequently enhanced piglet BW gain.