Effect of dietary fiber fermentation on short-chain fatty acid production and microbial composition in vitro.

BACKGROUND: The efficient utilization of fiber-rich co-products is important for optimizing feed resource utilization and animal health. This study was conducted to evaluate the fermentation characteristics of fiber-rich co-products, which had equal quantities of total dietary fiber (TDF), at different time points using batch in vitro methods. It considered their gas production, short-chain fatty acid (SCFA) production, and microbial composition. RESULTS: The fermentation of wheat bran (WB) and oat bran (OB) showed higher and faster (P < 0.05) gas and SCFA production than corn bran (CB), sugar beet pulp (SBP), and soybean hulls (SH). The α-diversity was higher in the CB, SBP, and SH groups than in the WB and OB groups (P < 0.05). At the phylum level, OB and WB fermentation showed lower (P < 0.05) relative abundance of Actinobacteria than the CB, SBP, and SH groups. At the genus level, OB and WB fermentation increased the Enterococcus population in comparison with the CB, SBP, and SH groups, whereas CB and SBP fermentation improved the relative abundance of the Christensenellaceae R-7 group more than the WB, OB, and SH groups (P < 0.05). CONCLUSION: Overall, WB and OB were rapidly fermented by fecal microbiota, in contrast with SBP, SH, and CB. Fermentation of different fiber-rich co-products with an equal TDF content gives different responses in terms of microbial composition and SCFA production due to variations in their physicochemical properties and molecular structure. © 2020 Society of Chemical Industry.

Perturbation of the lipid metabolism and intestinal inflammation in growing pigs with low birth weight is associated with the alterations of gut microbiota.

Low birth weight (LBW) is accompanied by metabolic dysfunction, chronic inflammation and gut microbiota perturbation in piglets during early life. Regulating gut microbiota structure can indirectly or directly affect gut health and the host's metabolism. However, whether gut microbiota dysbiosis impact lipid metabolism and inflammation progression in the LBW pigs later in life is unclear. In the present study, we investigated the role of gut microbiota on homeostasis in organisms using young pigs as a model. The plasma concentrations of High-density lipoproteins (HDLC) and pro-inflammatory cytokines such as Interleukin 6 (IL-6), Tumor necrosis factor alpha (TNF-α) and Interleukin 18 (IL-18) were increased in LBW pigs. The bacterial composition was modified dramatically in LBW group in association with an increase in propionate, butyrate and Short-chain fatty acids (SCFAs) in the ileal digesta. LBW impaired intestine results in damaged Fatty acid-binding protein 1 (FABP2) and Fatty acid-binding protein 4 (FABP4) expressions, and the inhibition of Free fatty acid receptor 1 (FFAR1), Free fatty acid receptor 2 (FFAR2) and G protein-coupled receptor 119 (GPR119) expressions, causing inefficient SCFAs absorption. Meanwhile, the physical barrier and chemical barrier related to functional gene expressions of Occludin, Claudin-1, Mucin 1 (MUC1) and Mucin 2 (MUC2) in both ileum and colon were decreased in the LBW pigs. The genera of Blautia, Bifidobacterium, Subdoligranulum and Coprococcus 3 in the ileum were correlated positively with lipid metabolic dysfunction and pro-inflammatory response in LBW pigs. Collectively, the gut microbiota is critical for perturbation of lipid metabolism and inflammatory progression in LBW pigs, which suggests the interventions for modulating bacterial communities may be therapeutically beneficial for metabolic diseases and chronic inflammation.

[Community structure of phytoplankton and its relationships with environmental factors in surface water of Ankang Reservoir, Northwest China].

To evaluate trophic state and biotic community as well as the relationship between phytoplankton community composition and environmental factors in surface water of Ankang Reservoir, the water and phytoplankton were sampled monthly from January to December in 2012. The phytoplankton distribution and the physical and chemical indicators were analyzed. The characteristics of phytoplankton community were studied via Shannon diversity index (H) and Pielou evenness index (J). The trophic level was assessed via physical and chemical indicators, and trophic state index (TSI). One hundred and ten genera belonging to seven phyla were identified. The abundance of phytoplankton ranged from 0.11 x 10(4) to 2.08x10(4) cells . L-1. The composition of phytoplankton and distribution of pollution indicator species, biodiversity and TSI indicated that surface water of Ankang Reservoir belonged to the ecological middling pollution type and was at a mesotrophic level. High-density feeding aquaculture and direct discharge of domestic wastewater had adverse effects on water quality. The water quality of Lanhe River, a tributary of Hanjiang River, was poor. Canonical correspondence analysis (CCA) showed that the impacts of the eight tested environmental factors on phytoplankton community composition and distribution varied in different seasons. Moreover, nitrogen was the main nutrient factor affecting the community composition of the phytoplankton. The physical and chemical indicators showed that the water quality of surface water of Ankang Reservoir was generally good and satisfied the standard of class II water. However, the quality of total nitrogen poorer than the standard of class II water in several sampling sites suggested that the water quality of Ankang Reservoir had the trend to be deteriorated.