Tiwari Utsav P, Mandal Rabindra K, Neupane Kabi Raj, Mishra Birendra, Jha Rajesh
Department of Human Nutrition, Food and Animal Sciences, University of Hawaii at Manoa, 1955 East-West Rd, Honolulu, HI, 96822, USA.
Indiana University School of Medicine, Indiana, USA.
J Anim Sci Biotechnol. 2022 May 3;13(1):53. doi: 10.1186/s40104-022-00699-y.
Alternative feedstuffs may contribute to reducing feed costs of pig production. But these feedstuffs are typically rich in fiber and resistant starch (RS). Dietary fibers and RS are fermented in the gastrointestinal tract (GIT) and modulate the microbial community. Certain microbes in the GIT can promote host health, depending on the type of fermentation substrates available. In this study, six alternative feedstuffs (three starchy: Okinawan sweet potato, OSP; yam, and taro, and three fibrous: wheat millrun, WMR; barley brewers grain, BBG; and macadamia nut cake, MNC) were evaluated for their in vitro digestibility and fermentation characteristics and their effects on pig's hindgut microbial profile. After 2 steps of enzymatic digestion assay, residues were fermented using fresh pig feces as microbial inoculum, and gas production was recorded periodically for 72 h and modeled for fermentation kinetics. After fermentation, the residual liquid phase was analyzed for short-chain fatty acid (SCFA), and the solid phase was used to determine the nutrient's digestibility and microbial community.
In vitro ileal digestibility of dry matter and gross energy was higher in starchy than fibrous feedstuffs. Total gas and SCFA production were significantly higher (P < 0.001) in starchy feedstuffs than fibrous feedstuffs. Both acetate and propionate production was significantly higher (P < 0.001) in all starchy feedstuffs than BBG and MNC; WMR was in between. Overall alpha diversity was not significantly different within and between starchy and fibrous feedstuffs. Beta diversity (measured using bray Curtis dissimilarity distance) of starchy feedstuffs was significantly different (P < 0.005) than fibrous feedstuffs.
Starchy feedstuffs acted as a substrate to similar types of microbes, whereas fibrous feedstuffs resulted in a more diverse microbial population. Such alternative feedstuffs may exert comparable beneficial effects, thus may be included in swine diets to improve gut health.
替代饲料可能有助于降低生猪生产的饲料成本。但这些饲料通常富含纤维和抗性淀粉（RS）。膳食纤维和RS在胃肠道（GIT）中发酵并调节微生物群落。胃肠道中的某些微生物可促进宿主健康，这取决于可用发酵底物的类型。在本研究中，评估了六种替代饲料（三种含淀粉的：冲绳甘薯、山药和芋头，以及三种含纤维的：小麦麸皮、大麦酒糟和澳洲坚果饼）的体外消化率和发酵特性及其对猪后肠微生物谱的影响。经过两步酶消化试验后，使用新鲜猪粪便作为微生物接种物对残留物进行发酵，并定期记录72小时的产气量，并对发酵动力学进行建模。发酵后，分析残留液相中的短链脂肪酸（SCFA），并使用固相来确定养分消化率和微生物群落。
含淀粉饲料的干物质和总能的体外回肠消化率高于含纤维饲料。含淀粉饲料的总产气量和SCFA产量显著高于含纤维饲料（P < 0.001）。所有含淀粉饲料中的乙酸盐和丙酸盐产量均显著高于大麦酒糟和澳洲坚果饼（P < 0.001）；小麦麸皮介于两者之间。含淀粉和含纤维饲料内部和之间的总体α多样性没有显著差异。含淀粉饲料的β多样性（使用布雷-柯蒂斯差异距离测量）与含纤维饲料显著不同（P < 0.005）。
含淀粉饲料作为类似类型微生物的底物，而含纤维饲料导致微生物种群更加多样化。此类替代饲料可能发挥类似的有益作用，因此可纳入猪日粮以改善肠道健康。
