Effect of biochanin A on the rumen microbial community of Holstein steers consuming a high fiber diet and subjected to a subacute acidosis challenge

Subacute rumen acidosis (SARA) occurs when highly fermentable carbohydrates are introduced into the diet, decreasing pH and disturbing the microbial ecology of the rumen. Rumen amylolytic bacteria rapidly catabolize starch, fermentation acids accumulate in the rumen and reduce environmental pH. Historically, antibiotics (e.g., monensin, MON) have been used in the prevention and treatment of SARA. Biochanin A (BCA), an isoflavone produced by red clover (Trifolium pratense), mitigates changes associated with starch fermentation ex vivo. The objective of the study was to determine the effect of BCA on amylolytic bacteria and rumen pH during a SARA challenge. Twelve rumen fistulated steers were assigned to 1 of 4 treatments: HF CON (high fiber control), SARA CON, MON (200 mg d-1), or BCA (6 g d-1). The basal diet consisted of corn silage and dried distiller’s grains ad libitum. The study consisted of a 2-wk adaptation, a 1-wk HF period, and an 8-d SARA challenge (d 1–4: 40% corn; d 5–8: 70% cracked corn). Samples for pH and enumeration were taken on the last day of each period (4 h). Amylolytic, cellulolytic, and amino acid/peptide-fermenting bacteria (APB) were enumerated. Enumeration data were normalized by log transformation and data were analyzed by repeated measures ANOVA using the MIXED procedure of SAS. The SARA challenge increased total amylolytics and APB, but decreased pH, cellulolytics, and in situ DMD of hay (P < 0.05). BCA treatment counteracted the pH, microbiological, and fermentative changes associated with SARA challenge (P < 0.05). Similar results were also observed with MON (P < 0.05). These results indicate that BCA may be an effective alternative to antibiotics for mitigating SARA in cattle production systems.

Increasing Dietary Amylose Reduces Rate of Starch Digestion and Stimulates Microbial Fermentation in Weaned Pigs

Objectives Starch with increasing ratio of amylose to amylopectin decreases ileal starch digestibility in pigs. Microbes in the large intestine ferment undigested starch and produce short-chain fatty acids (SCFA). The benefits of SCFA in modulating gut health stimulated interest in dietary strategies to increase microbial carbohydrate fermentation and digesta SCFA in pigs and humans. We studied effects of increasing dietary amylose on SCFA and the expression of transporters of glucose (sodium-glucose cotransporter 1, SGLT1) and SCFA (monocarboxylic acid transporter 1, MCT1; sodium-coupled monocarboxylate transporter, SMCT), and sweet taste receptor type 1, member 3 (T1R3) along the intestine of weaned pigs. Methods Weaned pigs (n = 32; 8.4 kg) were allocated to 1 of 4 diets containing 67% purified starch with 0, 20, 35, or 70% amylose in randomized complete blocks. On day 21, 47-day-old pigs were euthanized to collect digesta for SCFA and intestinal tissue for molecular analyses. Results Ileal starch digestibility was 44% lower and hindgut starch fermentation was 14% greater in pigs fed 70% amylose (P &lt; 0.05). Increasing dietary amylose increased (P &lt; 0.05) acetate and total SCFA in the cecum, butyrate in proximal and mid colon, and propionate and valerate throughout the colon. Increasing dietary amylose downregulated (P &lt; 0.001) SGLT1 and T1R3 in the jejunum and upregulated (P &lt; 0.001) MCT1 in the ileum. Ileal starch digestibility was inversely associated with MCT1 expression in the ileum (R2 = 0.41, P &lt; 0.05). In the cecum, 35% amylose downregulated expressions of MCT1 and SMCT (R2 = 0.64, P &lt; 0.001). Both 35 and 70% amylose regulated SMCT expression down in proximal colon (P &lt; 0.001) but up in mid colon (P &lt; 0.001). Weak associations (R2 = 0.20, P &lt; 0.05) existed between SMCT and butyrate and valerate in mid colon. Conclusions Increasing dietary amylose in weaned pigs decreased ileal starch digestion and stimulated hindgut starch fermentation thereby increasing digesta total SCFA in cecum and colon. Consequently, expression of SCFA transporters was increased in the ileum supporting the conversion by dietary amylose of the pig from starch digester into starch fermenter. Funding Sources Swine Innovation Porc, Alberta Pork, and Discovery Grant of Natural Sciences and Engineering Research Council of Canada.

Bioethanol Production from Cassava Peel Treated with Sulfonated Carbon Catalyzed Hydrolysis

A large amount of Cassava peel as biomass waste is generated by agricultural activities, and it led to a new pursuit to exploit the utilization of biomass waste. This research aimed to study the potential of Cassava peel as raw material for bioethanol production. This study was performed in 2 main processes, acid hydrolysis, and fermentation. The experiment was initiated by conducting acid hydrolysis (100°C and 60 min) on Cassava peel’s starch using sulfonated carbon catalyst palm oil empty fruit bunch (5%-w/v) to produce 13.53 g/L glucose. The glucose contained hydrolysates then continued to ferment at 30°C. The effect of fermentation time (h), pH, and shaking rate (rpm) of cassava peel’s starch fermentation using Saccharomyces cerevisiae was analyzed. The best result was found at pH 4.5 and 50 rpm for a 24 h reaction with 3.75 g/L of bioethanol concentration. This study revealed that Cassava peel is a promising feedstock for biofuel production.

A Natural Antifungal from Cassava Starch Fermentation Wastewater

Sour cassava starch production process, during the fermentation step, an acidic wastewater is generated, in this study named wastewater of cassava starch fermentation (WCSF). It has been studied the effect of WCSFs (from three industrial source: WCSF 1, 2 and 3) and patterns of organic acids (lactic, acetic, propionic and butyric acids, which were the main organic acids present in the WCSFs) singly or together on the development and growing of Botrytis cinerea, Monilinia fructicola and Colletotrichum gloeosporiodes. WCSFs showed antimicrobial effect on the three fungi studied. WCSF2 inhibited the germination of conidia from the three fungi, while WCSFs 1 and 3 inhibited conidia germination of B. cinerea and C. gloeosporiodes. The acetic, propionic, butyric and the mix acids were also effective in the reduction of conidial germination. In the analysis of mycelia growth, it has been observed that the growing was statically smaller, in relation to negative control, for all fungi in the treatments with the WCSFs and with the pattern solution of butyric acid. Which suggest that the WCSFs compounds and butyric acid are effective inhibitor for fungi and justify future studies using this wastewater.

Muribaculaceae genomes assembled from metagenomes suggest genetic drivers of differential response to acarbose treatment in mice

The drug acarbose (ACA) is used to treat diabetes, and, by inhibiting α-amylase in the small intestine, increases the amount of starch entering the lower digestive tract. This results in changes to the composition of the microbiota and their fermentation products. Acarbose also increases longevity in mice, an effect that has been correlated with increased production of the short-chain fatty acids propionate and butyrate. In experiments replicated across three study sites, two distantly related species in the bacterial family Muribaculaceae were dramatically more abundant in ACA-treated mice, distinguishing these responders from other members of the family. Bacteria in the family Muribaculaceae are predicted to produce propionate as a fermentation end product and are abundant and diverse in the guts of mice, although few isolates are available. We reconstructed genomes from metagenomes (MAGs) for nine populations of Muribaculaceae to examine factors that distinguish species that respond positively to acarbose. We found two closely related MAGs (B1A and B1B) from one responsive species that both contain a polysaccharide utilization locus with a predicted extracellular α-amylase. These genomes also shared a periplasmic neopullulanase with another, distantly related MAG (B2) representative of the only other responsive species. This gene differentiated these three MAGs from MAGs representative of non-responding species. Differential gene content in B1A and B1B may be associated with the inconsistent response of this species to acarbose across study sites. This work demonstrates the utility of culture-free genomics for inferring the ecological roles of gut bacteria including their response to pharmaceutical perturbations.ImportanceThe drug acarbose is used to treat diabetes by preventing the breakdown of starch in the small intestine, resulting in dramatic changes in the abundance of some members of the gut microbiome and its fermentation products. In mice, several of the bacteria that respond most positively are classified in the family Muribaculaceae, members of which produce propionate as a primary fermentation product. Propionate has been associated with gut health and increased longevity in mice. We found that genomes of the most responsive Muribaculaceae showed signs of specialization for starch fermentation, presumably providing them a competitive advantage in the large intestine of animals consuming acarbose. Comparisons among genomes enhance existing models for the ecological niches occupied by members of this family. In addition, genes encoding one type of enzyme known to participate in starch breakdown were found in all three genomes from responding species, but none of the other genomes.

Transglycosylated starch accelerated intestinal transit and enhanced bacterial fermentation in the large intestine using a pig model

Resistant starch can alter the intestinal nutrient availability and bulk of digesta, thereby modulating the substrate available for microbial metabolic activity along the gastrointestinal tract. This study elucidated the effect of transglycosylated starch (TGS) on the retention of digesta in the upper digestive tract, ileal flow and hindgut disappearance of nutrients, and subsequent bacterial profiles in pigs. Fourteen ileal-cannulated growing pigs were fed either the TGS or control (CON) diet in a complete crossover design. Each period consisted of a 10-d adaptation to the diets, followed by 3-d collection of faeces and ileal digesta. Consumption of TGS decreased the retention of digesta in the stomach and small intestine, and increased ileal DM, starch, Ca and P flow, leading to enhanced starch fermentation in the hindgut compared with CON-fed pigs. TGS increased ileal and faecal total SCFA, especially ileal and faecal acetate and faecal butyrate. Gastric retention time positively correlated toKlebsiella, which benefitted together withSelenomonas,Lactobacillus,Mitsuokellaand Coriobacteriaceae from TGS feeding and ileal starch flow. Similar relationships existed in faeces with Coriobacteriaceae, Veillonellaceae andMegasphaerabenefitting most, either directly or indirectly via cross-feeding, from TGS residuals in faeces. TGS, in turn, depressed genera within Ruminococcaceae,Clostridialesand Christensenellaceae compared with the CON diet. The present results demonstrated distinct ileal and faecal bacterial community and metabolite profiles in CON- and TGS-fed pigs, which were modulated by the type of starch, intestinal substrate flow and retention of digesta in the upper digestive tract.

Pigs Ferment Enzymatically Digestible Starch when it Is Substituted for Resistant Starch

ABSTRACT Background Feeding behavior is controlled by satiety mechanisms, which are affected by the extent of starch digestion, and thus resistant starch (RS) intake. Alterations in feeding behavior to changes in RS intake may depend on the adaptation of processes involved when shifting from starch digestion to fermentation or vice versa. Objectives The aim of this study was to investigate how growing pigs adapt their feeding behavior in response to increasing and decreasing dietary RS concentrations. Methods Thirty-six groups of 6 pigs (25.4 ± 2.8 kg; Hypor Libra × Hypor Maxter; male:female, 1:1) were fed diets containing 50% high-amylose maize starch (high RS; HRS) or waxy maize starch (low RS; LRS). Over 28 d, diets were exchanged following a 5-step titration (25% per step) that was executed in the upward (LH) or downward direction (HL). Twelve groups received a control diet to correct for changes over time. Individual feeding behavior and total tract starch digestion and fermentation were evaluated. The response in each parameter to increasing dietary HRS inclusion was estimated through the use of linear regression procedures, and tested for titration direction and sex effects. Results Complete substitution of LRS with HRS increased the proportion of starch fermented, which was greater in LH pigs than in HL pigs (17.6% compared with 8.18%; P < 0.001), and decreased the feed intake (106 g/d; P = 0.021) and meal size (12.6 g; P < 0.001) of LH pigs, but not of HL pigs. In LH pigs, the size of the starch fermentation response positively correlated with the size of the feed intake response (r = 0.90, P < 0.001). Conclusions The attenuated response in starch fermentation in HL pigs indicates that pigs adapt more slowly to dietary supply of digestible starch than to RS, consequently resulting in fermentation of enzymatically digestible starch. Feed intake and feeding behavior only changed in pigs poorly adapting to RS, indicating that adequacy of adaptation, rather than RS itself, drives feed intake. These findings stress the importance of diet history for nutrient digestion and feeding behavior.