Starchy and fibrous feedstuffs differ in their in vitro digestibility and fermentation characteristics and differently modulate gut microbiota of swine

Effects of Dioscorea oppositifolia L. on growth performance, biochemical indicators, immunity, and intestinal health of weaned piglets

Introduction

Weaning stress syndrome in piglets seriously endangers the healthy development of the breeding industry. Dioscorea oppositifolia L. (Chinese yam, YAM) has activities such as boosting immunity and regulating gastrointestinal function. In order to explore the potential efficacy of YAM on weaned piglets, this study aimed to investigate the effects of growth performance, immune function, intestinal health and intestinal flora composition of weaned piglets.

Methods

Forty-eight 28-day-old weaned piglets were randomly divided into a control group, YAML group and YAMH group, with 0, 1 and 2% YAM added to the basal diet, respectively. During the experiment, the piglets' feed intake was recorded, and blood and fecal samples were collected. After the feeding period, intestinal tissue samples and colon content samples were collected for testing.

Results

The results showed that adding YAM to the diet can lower the incidence of diarrhea in weaned piglets, improve growth performance and nutrient digestibility, and reduce serum enzyme activity alanine aminotransferase (ALT), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C); in addition, YAM can also increase serum immunoglobulins (Ig) and antibody titers, regulate the level of inflammatory factors, and promote the expression of secretory immunoglobulin A (SIgA) protein in the intestine. Furthermore, supplementation with YAM can increase the villus height (VH), the ratio of villus height to crypt depth (V/C), and the expression of Tight junctions (TJs), and also has a positive regulatory effect on the intestinal flora.

Discussion

In summary, YAM alleviates weaning stress syndrome in piglets by promoting growth performance, improving immune function and disease resistance, improving intestinal morphology and mucosal immunity, and regulating the intestinal microbial composition of piglets. This provides a theoretical basis for the development and application of YAM as a new plant-derived feed additive.

Dietary inclusion of high-amylose cornstarch increased Lactobacillus and Terrisporobacter and decreased Streptococcus in the cecal digesta of weanling pigs

The study investigated the effect of dietary inclusion of high-amylose cornstarch (HA-starch) on cecal microbiota composition and volatile fatty acid (VFA) concentrations in weanling pigs fed high levels of cold-pressed canola-cake (CPCC). Weaned pigs (240 mixed sex; 7.1 ± 1.2 kg) were housed in 40 pens (6 pigs/pen) and fed a common commercial diet for 7 d, followed by the experimental diets for 28-d, which contained either 0% or 40% CPCC with either 0% or 40% HA-starch. At the end of the study, one pig from each pen (n = 8) was selected and euthanized to collect cecal digesta for microbial and VFA composition analyses. The HA-starch increased (P < 0.001) acetate, propionate, and butyrate concentrations, thereby increasing total VFA concentration (P < 0.001). There was a tendency for cecal butyrate and total VFA concentrations to decrease when pigs were fed the 40% CPCC diet without HA-starch but increase when fed the 40% CPCC diet containing 40% HA-starch (CPCC × HA-starch effect; P = 0.09), indicating HA-starch can increase cecal butyrate and total VFA concentrations in pigs fed a diet with high-CPCC level. The proportions of Lactobacillus and Terrisporobacter were high, whereas low proportions of Streptococcus genus were observed in the cecal microbiota of pigs fed diets containing 40% HA-starch. Also, pathways consistent with carbohydrate digestion, absorption, and phosphate metabolism were enriched in pigs when the diet included 40% HA-starch. In summary, incorporating high amounts of HA-starch in a weanling pig diet containing high levels of CPCC may benefit intestinal health and digestive performance by enhancing the abundance of probiotic commensal bacteria, contributing to increased enzymatic activity and carbohydrate metabolism.

Relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization, energy metabolism, and gut microbiota in growing pigs

BACKGROUND

There is a growing focus on using various plant-derived agricultural by-products to increase the benefits of pig farming, but these feedstuffs are fibrous in nature. This study investigated the relationship between dietary fiber physicochemical properties and feedstuff fermentation characteristics and their effects on nutrient utilization, energy metabolism, and gut microbiota in growing pigs.

METHODS

Thirty-six growing barrows (47.2 ± 1.5 kg) were randomly allotted to 6 dietary treatments with 2 apparent viscosity levels and 3 β-glucan-to-arabinoxylan ratios. In the experiment, nutrient utilization, energy metabolism, fecal microbial community, and production and absorption of short-chain fatty acid (SCFA) of pigs were investigated. In vitro digestion and fermentation models were used to compare the fermentation characteristics of feedstuffs and ileal digesta in the pig's hindgut.

RESULTS

The production dynamics of SCFA and dry matter corrected gas production of different feedstuffs during in vitro fermentation were different and closely related to the physical properties and chemical structure of the fiber. In animal experiments, increasing the dietary apparent viscosity and the β-glucan-to-arabinoxylan ratios both increased the apparent ileal digestibility (AID), apparent total tract digestibility (ATTD), and hindgut digestibility of fiber components while decreasing the AID and ATTD of dry matter and organic matter (P < 0.05). In addition, increasing dietary apparent viscosity and β-glucan-to-arabinoxylan ratios both increased gas exchange, heat production, and protein oxidation, and decreased energy deposition (P < 0.05). The dietary apparent viscosity and β-glucan-to-arabinoxylan ratios had linear interaction effects on the digestible energy, metabolizable energy, retained energy (RE), and net energy (NE) of the diets (P < 0.05). At the same time, the increase of dietary apparent viscosity and β-glucan-to-arabinoxylan ratios both increased SCFA production and absorption (P < 0.05). Increasing the dietary apparent viscosity and β-glucan-to-arabinoxylan ratios increased the diversity and abundance of bacteria (P < 0.05) and the relative abundance of beneficial bacteria. Furthermore, increasing the dietary β-glucan-to-arabinoxylan ratios led to a linear increase in SCFA production during the in vitro fermentation of ileal digesta (P < 0.001). Finally, the prediction equations for RE and NE were established.

CONCLUSION

Dietary fiber physicochemical properties alter dietary fermentation patterns and regulate nutrient utilization, energy metabolism, and pig gut microbiota composition and metabolites.

Colonic Microbiota Improves Fiber Digestion Ability and Enhances Absorption of Short-Chain Fatty Acids in Local Pigs of Hainan

Compared to commercial breeds, Chinese local pig breeds have a greater ability to digest dietary fiber, which may be due to differences in intestinal microbiota. In this study, we fed Ding'an and DLY pigs high and low levels of dietary fiber, respectively, to investigate factors contributing to high dietary fiber adaption in Ding'an pigs. Twelve Ding'an pigs and DLY pigs were randomly divided into a 2 (diet) × 2 (breed) factorial experiment (n = 3). Compared with commercial pigs, Ding'an pigs have a stronger ability to digest dietary fiber. Prevotella was more prevalent in Ding'an pigs than in DLY pigs, which may be an important reason for the stronger ability of fiber degradation in Ding'an pigs. When the effects of feed and breed factors are considered, differences in abundance of 31 species and 14 species, respectively, may result in a greater ability of fiber degradation in Ding'an pigs. Among them, Prevotella. sp. CAG:520 may be a newly discovered bacterium related to fiber degradation, which positively correlated with many fiber-degrading bacteria (r > 0.7). We also found that the concentration of plant metabolites with anti-inflammatory and antioxidant effects was higher in the colonic chyme of Ding'an pigs after increasing the fiber content, which resulted in the downregulated expression of inflammatory factors in colonic mucosa. Spearman's correlation coefficient revealed a strong correlation between microbiota and the apparent digestibility of dietary fiber (r > 0.7). The mRNA expressions of SLC16A1, PYY, and GCG were significantly increased in the colonic mucosa of Ding'an pigs fed on high-fiber diets, which indicates that Ding'an pigs have an enhanced absorption of SCFAs. Our results suggested that an appropriate increase in dietary fiber content can reduce the inflammatory response and improve feed efficiency in Ding'an pigs, and differences in the intestinal microbial composition may be an important reason for the difference in the fiber degradation capacity between the two breeds of pigs.

Salmonella enterica induces biogeography-specific changes in the gut microbiome of pigs

Swine are a major reservoir of an array of zoonotic Salmonella enterica subsp. enterica lineage I serovars including Derby, Typhimurium, and 4,[5],12:i:- (a.k.a. Monophasic Typhimurium). In this study, we assessed the gastrointestinal (GI) microbiome composition of pigs in different intestinal compartments and the feces following infection with specific zoonotic serovars of S. enterica (S. Derby, S. Monophasic, and S. Typhimurium). 16S rRNA based microbiome analysis was performed to assess for GI microbiome changes in terms of diversity (alpha and beta), community structure and volatility, and specific taxa alterations across GI biogeography (small and large intestine, feces) and days post-infection (DPI) 2, 4, and 28; these results were compared to disease phenotypes measured as histopathological changes. As previously reported, only S. Monophasic and S. Typhimurium induced morphological alterations that marked an inflammatory milieu restricted to the large intestine in this experimental model. S. Typhimurium alone induced significant changes at the alpha- (Simpson's and Shannon's indexes) and beta-diversity levels, specifically at the peak of inflammation in the large intestine and feces. Increased community dispersion and volatility in colonic apex and fecal microbiomes were also noted for S. Typhimurium. All three Salmonella serovars altered community structure as measured by co-occurrence networks; this was most prominent at DPI 2 and 4 in colonic apex samples. At the genus taxonomic level, a diverse array of putative short-chain fatty acid (SCFA) producing bacteria were altered and often decreased during the peak of inflammation at DPI 2 and 4 within colonic apex and fecal samples. Among all putative SCFA producing bacteria, Prevotella showed a broad pattern of negative correlation with disease scores at the peak of inflammation. In addition, Prevotella 9 was found to be significantly reduced in all Salmonella infected groups compared to the control at DPI 4 in the colonic apex. In conclusion, this work further elucidates that distinct swine-related zoonotic serovars of S. enterica can induce both shared (high resilience) and unique (altered resistance) alterations in gut microbiome biogeography, which helps inform future investigations of dietary modifications aimed at increasing colonization resistance against Salmonella through GI microbiome alterations.

A combined pig model to determine the net absorption of volatile fatty acids in the large intestine under different levels of crude fiber

BACKGROUND

This study aimed to develop a combined model to quantify the net absorption of volatile fatty acids (VFA) in the large intestine (LI) of pigs.

METHODS

Fifteen female growing pigs (Duroc × Large White × Landrace) were ranked by body weight (30 ± 2.1 kg) on day 0 and assigned to one of three treatments, namely the basal diet containing different crude fiber (CF) levels (LCF: 3.0% CF, MCF: 4.5% CF, and HCF: 6.0% CF). The pigs were implanted with the terminal ileum fistula and the cannulation of the ileal mesenteric vein (IMV), portal vein (PV), and left femoral artery (LFA) from days 6 to 7. [13 C]-Labeled VFA and P-aminohippuric acid were constantly perfused into the terminal ileum fistula and the cannulation of the IMV (day 15), respectively. Blood samples were collected from the PV and the LFA during perfusion (5 h), and LI samples were collected.

RESULTS

The net flux of [12 C]-acetic acid in the PV was greater for LCF versus MCF (p = 0.045), but no difference was observed in the net flux of [12 C]-propionic acid (p = 0.505) and [12 C]-butyric acid (p = 0.35) in the PV among treatments. The deposition of [12 C]-acetic acid in the LI was greater for LCF versus MCF (p = 0.014), whereas the deposition of [12 C]-propionic acid (p = 0.007) and [12 C]-butyric acid (p = 0.037) in the LI was greater for LCF versus HCF.

CONCLUSIONS

In conclusion, this pig model was found conducive to study the net absorption of VFAs in the LI, and LCF had more net absorption of VFAs in the LI than MCF and HCF.

β-glucosidase, driven by porcine transthyretin promoter, specific expression in the liver of transgenic mice

Under the background of food security, using non-grain feed instead of corn-soybean-based feed is an effective measure to alleviate the food-feed competition. While, non-grain feeds are often rich in fiber, which cannot be digested by non-ruminants. Producing heterologous enzymes in non-ruminants to improve cellulose utilization rate is a new research strategy by transgenic technology. In this study, porcine transthyretin (TTR) promoter, signal peptide-coding sequence (CDS), Saccharomycopsis fibuligera β-glucosidase gene (BGL1)-CDS, 6×His sequences fragments were fused into pGL3-control vector to generate transgenic vector. Then, transgenic mice were generated by pronuclear microinjection of the linearized expression vectors. Transgenic mice and their offspring were examined by PCR-based genotyping and copy number variation. Results showed that BGL1 was successfully integrated into the mouse genome and transmitted stably. Furthermore, reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and β-glucosidase activity assay demonstrated that BGL1 was specifically expressed in the liver, and β-glucosidase activity significantly increased. In addition, liver weight index, cellular morphology, and collagen fiber content of the liver showed that exogenous gene insertion did not cause any lesions to live. Taken together, our findings suggest that β-glucosidase driven by TTR promoter was specifically expressed in the liver of transgenic mice.

The interaction between dietary fiber and gut microbiota, and its effect on pig intestinal health

Intestinal health is closely associated with overall animal health and performance and, consequently, influences the production efficiency and profit in feed and animal production systems. The gastrointestinal tract (GIT) is the main site of the nutrient digestive process and the largest immune organ in the host, and the gut microbiota colonizing the GIT plays a key role in maintaining intestinal health. Dietary fiber (DF) is a key factor in maintaining normal intestinal function. The biological functioning of DF is mainly achieved by microbial fermentation, which occurs mainly in the distal small and large intestine. Short-chain fatty acids (SCFAs), the main class of microbial fermentation metabolites, are the main energy supply for intestinal cells. SCFAs help to maintain normal intestinal function, induce immunomodulatory effects to prevent inflammation and microbial infection, and are vital for the maintenance of homeostasis. Moreover, because of its distinct characteristics (e.g. solubility), DF is able to alter the composition of the gut microbiota. Therefore, understanding the role that DF plays in modulating gut microbiota, and how it influences intestinal health, is essential. This review gives an overview of DF and its microbial fermentation process, and investigates the effect of DF on the alteration of gut microbiota composition in pigs. The effects of interaction between DF and the gut microbiota, particularly as they relate to SCFA production, on intestinal health are also illustrated.

Evaluation of in vitro starch digestibility and chemical composition in pasta former foods

Former food products include various leftovers from the food industry which, although they have lost values for human consumption, could be safely used for livestock, thus limiting environmental impact of food waste, and reducing feeding costs. The aim of this study was to investigate the nutritional characteristics of different types of former foods from pasta industry. Four types of dry pasta refusal (wholemeal, semolina, purple, and tricolor) and whole barley grain (control) were analyzed for chemical composition and in vitro starch digestibility; the energy content was also estimated. For each product type, samples collected in three different times at a pasta plant were analyzed. All products showed higher (p &lt; 0.001) protein contents and lower (p &lt; 0.001) fat contents than barley. The amount of NDF varied between the samples (p &lt; 0.001), while all samples reported high starch content (&gt;60% DM). The energy content was higher (p &lt; 0.05) in pasta former food compared with whole barley grain. Purple pasta showed different in vitro starch digestibility compared to the other former foods (p &lt; 0.001). However, all products showed higher values of resistant starch, whereas barley was mainly composed by slowly digestible starch. The results indicated that dry pasta former foods could be suitable energy sources for feeding pig, but their inclusion in diets must consider the slow digestibility.