Effects of Dietary Fiber Type on Growth Performance, Serum Parameters and Fecal Microbiota Composition in Weaned and Growing-Finishing Pigs

SIMPLE SUMMARY: Much evidence has indicated that dietary fiber plays an important role in regulating performance and intestinal health of the pigs. Dietary fiber is divided into soluble (SDF) and insoluble dietary fiber (IDF) based on solubility. SDF is easier to be fermented by gut microbiota to produce more volatile fatty acids (VFA) than IDF, and IDF is beneficial to development of the gastrointestinal tract and microbial diversity. Until now, effects of different SDF to IDF ratios on pig performance and their microbial community have not been clear. To provide a scientifically recommended requirement of fiber types for pig nutrition, this study was conducted to explore the roles of different SDF to IDF ratios in weaned and growing-finishing pigs. ABSTRACT: The objective of this study was to evaluate the effects of different SDF to IDF ratios on growth performance, serum indexes and fecal microbial community in pigs. Weaned and growing-finishing pigs were fed a diet containing five different ratios of SDF to IDF from 1:5 to 1:9 and from 1:3 to 1:7, respectively. Results showed a linear tendency that average daily gain (ADG) of weaned pigs decreased but the feed intake to weight gain ratio (F/G) increased as the ratio of SDF to IDF increased from 1:5 to 1:9 (p = 0.06). The ADG of growing-finishing pigs showed quadratic changes (p < 0.05) as ratios of SDF to IDF increased from 1:3 to 1:7. The Shannon index of fecal microbial diversity increased first and then decreased as the SDF to IDF ratio increased from 1:5 to 1:9 (p < 0.05). The Shannon and Chao indexes of fecal microbial diversity in growing-finishing pigs showed significant incremental linearly as the SDF to IDF ratio increased from 1:3 to 1:7 (p < 0.05). In conclusion, the recommended inclusion ratios of SDF to IDF in weaned and growing-finishing pigs diets are 1:7 and 1:5.