Effects of feeding fiber-fermenting bacteria to pigs on nutrient digestion, fecal output, and plasma energy metabolites

Diet-gut microbial interactions influence cancer immunotherapy

The gut microbiome is involved in the absorption and metabolism of host nutrients and modulates the immune response, affecting the efficacy of immunotherapy for cancer. In patients receiving immunotherapy, appropriate modifications of gut microbiota are thought to improve therapeutic response. Of all the factors that influence the gut microbiota, diet is the most influential and modifiable. Healthy dietary patterns as well as some specific dietary components can help the growth of beneficial microbiota in the gut, thereby protecting against cancers and promoting human health. A growing number of researches have confirmed the positive effects of a diet-gut microbiota approach as an adjuvant therapy for cancer, but controversy remains. Here, we summarize the interactions between diet and gut microbes based on previous studies, and discuss the role of gut microbiota-based dietary strategies in tumor immunotherapy, with the potential mechanisms of actions also intensively discussed.

Swine diets impact manure characteristics and gas emissions: Part II sulfur source

Sulfur is a key nutrient in swine diets and is associated with hydrogen sulfide (H₂S) emissions, odor, and respiratory distress of animals. Due to potential increases in S levels in swine diets by using alternative feedstuffs, a feeding trial study was conducted to determine the effect of dietary S source has on manure slurry chemical properties and gas emissions. A total of 24 gilts averaging 139 kg BW were fed a control diet formulated with corn and soybean meal (CSBM) containing 1.80 g S kg^-1 or diets containing 3.50 g S kg^-1 feed as supplied by calcium sulfate (CaSO₄), distillers dried grains with solubles (DDGS), or feather meal (CFM). Diets were fed for 41 d with an ADFI of 2.70 kg/d. Feces and urine were collected twice daily after each feeding and added to the manure storage containers. At the end of the study, manure slurries were monitored for gas emissions and chemical properties. Dietary S source had a significant effect on excretion of DM, C, N, and S in manure. Pigs fed the diets containing DDGS had significantly higher levels of NH₃, VFAs, and phenols in manure compared to pigs fed the CSBM diet. Pigs fed diets with organic S (i.e., DDGS and CFM) had lower emissions of H₂S compared to pigs fed the diet with inorganic sulfur (CaSO₄). In contrast, there were no significant differences in C or N emissions as affected by dietary treatment. Odor and odorant emissions differed by dietary treatment, with pigs fed the CFM diet having the highest odor emissions as compared to pigs fed the control CSBM diet. Pigs fed diets containing CFM and DDGS had a greater percentage of their chemical odor associated with volatile organic compounds while animals fed the CSBM diet or the diet with CaSO₄ had greater percentage associated with H₂S emissions.

Systematic review of the effects of the intestinal microbiota on selected nutrients and non-nutrients

PURPOSE

There is considerable interest in the effects of the intestinal microbiota (IM) composition, its activities in relation with the metabolism of dietary substrates and the impact these effects may have in the development and prevention of certain non-communicable diseases. It is acknowledged that a complex interdependence exists between the IM and the mammalian host and that the IM possesses a far greater diversity of genes and repertoire of metabolic and enzymatic capabilities than their hosts. However, full knowledge of the metabolic activities and interactions of the IM and the functional redundancy that may exist are lacking. Thus, the current review aims to assess recent literature relating to the role played by the IM in the absorption and metabolism of key nutrients and non-nutrients.

METHODS

A systematic review (PROSPERO registration: CRD42015019087) was carried out focussing on energy and the following candidate dietary substrates: protein, carbohydrate, fat, fibre, resistant starch (RS), and polyphenols to further understand the effect of the IM on the dietary substrates and the resulting by-products and host impacts. Particular attention was paid to the characterisation of the IM which are predominantly implicated in each case, changes in metabolites, and indirect markers and any potential impacts on the host.

RESULTS

Studies show that the IM plays a key role in the metabolism of the substrates studied. However, with the exception of studies focusing on fibre and polyphenols, there have been relatively few recent human studies specifically evaluating microbial metabolism. In addition, comparison of the effects of the IM across studies was difficult due to lack of specific analysis/description of the bacteria involved. Considerable animal-derived data exist, but experience suggests that care must be taken when extrapolating these results to humans. Nevertheless, it appears that the IM plays a role in energy homeostasis and that protein microbial breakdown and fermentation produced ammonia, amines, phenols and branch chain fatty acids, and a greater diversity in the microbes present. Few recent studies appear to have evaluated the effect of the IM composition and metabolism per se in relation with digestible dietary carbohydrate or fat in humans. Intakes of RS and prebiotics altered levels of specific taxa that selectively metabolised specific prebiotic/carbohydrate-type substances and levels of bifidobacteria and lactobacilli were observed to increase. In controlled human studies, consistent data exist that show a correlation between the intake of fibre and an increase in bifidobacteria and short-chain fatty acids, in particular butyrate, which leads to lower intestinal pH. Dietary polyphenols rely on modification either by host digestive enzymes or those derived from the IM for absorption to occur. In the polyphenol-related studies, a large amount of inter-individual variation was observed in the microbial metabolism and absorption of certain polyphenols.

CONCLUSIONS

The systematic review demonstrates that the IM plays a major role in the breakdown and transformation of the dietary substrates examined. However, recent human data are limited with the exception of data from studies examining fibres and polyphenols. Results observed in relation with dietary substrates were not always consistent or coherent across studies and methodological limitations and differences in IM analyses made comparisons difficult. Moreover, non-digestible components likely to reach the colon are often not well defined or characterised in studies making comparisons between studies difficult if not impossible. Going forward, further rigorously controlled randomised human trials with well-defined dietary substrates and utilizing omic-based technologies to characterise and measure the IM and their functional activities will advance the field. Current evidence suggests that more detailed knowledge of the metabolic activities and interactions of the IM hold considerable promise in relation with host health.

Effects of dirty housing and a Typhimurium DT104 challenge on pig growth performance, diet utilization efficiency, and gas emissions from stored manure

The objectives of this study were to elucidate the effects of a dirty environment and a challenge plus associated environmental contamination on pig growth performance, diet utilization efficiency, and gas emissions (CO, NH, CH, NO, and HS) from stored manure. Twenty-four weaned barrows, aged 31 d at initiation of the trial, were randomly allotted to 3 different treatments in a completely randomized design. Treatments were: pigs housed in cages with manure removed and cages washed daily (Clean); pigs housed in cages sprayed daily with manure slurry mixtures (Dirty); or pigs challenged with Typhimurium DT104 and housed in cages that were not washed, but manure was removed daily ( challenge). Rectal temperature, body weight, daily feed intake, manure output, manure composition, and gas emissions from stored manure were measured throughout the 24-d animal phase. The Dirty and challenge treatments were statistically compared to the Clean treatment to evaluate individual effects. Dirty housing tended to decrease ADG from d 1 to 24 ( = 0.06) but there were no other effects on pig performance compared with the Clean treatment. In contrast, a challenge was associated with a marked reduction in each of the measured indicators of pig performance. challenge increased the carbon to nitrogen ratio, ether extract, and lignin concentrations in excreted manure ( = 0.02, 0.01, 0.003, respectively), and increased manure and head space temperatures in manure tanks ( < 0.0001). Gas emissions from stored manure of pigs on the Dirty or treatments were increased for each of the measured gases as compared to the Clean treatment ( < 0.01) when expressed per unit of BW gain. When gas emissions from manure of pigs housed in the Dirty treatment were expressed per unit of manure volatile solids (VS), they were increased for NH, CH, and HS ( < 0.02). challenge was associated with increased emissions of CO, and NO and decreased emissions of HS per kilogram manure VS compared to the Clean treatment ( = 0.06, 0.03, 0.04, respectively). Collectively, these results indicated that a challenge and associated housing contamination caused depressed growth rate and increased manure gas emissions, while exposure to a Dirty environment slightly reduced growth performance and clearly increased manure gas emissions per unit of BW gain as compared to Clean control.

Growth performance, gastrointestinal microbial activity, and immunological response of piglets receiving microencapsulatedEnterococcus faecalisCG1.0007 and enzyme complex after an oral challenge withEscherichia coli(K88)

The aim of this study was to determine effects of dietary microencapsulated Enterococcus faecalis CG1.0007 probiotic and multienzyme complex (MC) in Enterotoxigenic Escherichia coli K88 (ETEC) challenged piglets. Thirty-six, 21-d-old weanling pigs were randomly allotted to four dietary treatments: a wheat–barley based negative control (NC), NC + MC, NC + probiotic, and NC + MC + probiotic. After 7-d acclimatization to treatments, pigs were weighed, blood was sampled, and then the pigs were orally challenged with an ETEC inoculum. After the challenge, blood was sampled at different time points; performance measures and fecal consistency scores were recorded; and on day 14, all pigs were killed to obtain intestinal tissue samples. During prechallenge, pigs receiving enzyme, probiotic, and a combination of both showed a significant improvement in daily gain (P = 0.03) and feed efficiency (P = 0.04) compared with control. During the postchallenge period, a greater (P = 0.05) ileal villus height was observed for diets supplemented with probiotic alone. Overall, pigs fed diets with probiotic alone also showed less incidence of diarrhea (P = 0.04) compared with control. In summary, the results indicate that dietary supplementation with microencapsulated Enterococcus faecalis CG1.0007 in weaned piglets challenged with ETEC was effective in controlling diarrhea.

Odor and Odorous Compound Emissions from Manure of Swine Fed Standard and Dried Distillers Grains with Soluble Supplemented Diets

This study was conducted to determine the impact of diets containing dried distillers grains with solubles (DDGS) on emissions of odor and odorous compounds from swine manure storage. Twenty-four pigs were fed either a corn-soybean meal (CSBM) diet or a diet containing 35% DDGS over a 42-d feeding trial. Their waste was collected and transferred to individual manure storage containers. Manure from pigs fed diets containing DDGS had significantly lower odorant emissions expressed in animal units for hydrogen sulfide (HS) and ammonia (NH) ( < 0.05) compared with pigs fed the CSBM diet, but emissions of volatile fatty acids and phenolic compounds were significantly higher ( < 0.05) for manures from animals fed the DDGS diet. There was no significant difference for indole compound emissions due to the dietary treatment applied. Emissions of volatile organic compounds (VOCs) from manure accounted for less than 0.1% of carbon consumed for either diet. There were no significant differences in odor emissions for either diet as quantified with human panels or measured as the sum total of the odor activity value. Manure odors from pigs fed the CSBM diet were dominated by HS, whereas animals fed the diet containing DDGS were dominated by VOCs.

Evaluation of wild herbivore faeces from South Africa as a potential source of hydrolytically active microorganisms

This study assessed faecal matter from three indigenous South African herbivores-zebra, giraffe and impala-as a potential source for hydrolytically active aerobic and facultatively anaerobic bacteria. Herbivore droppings were collected freshly in a local nature reserve in Pietermaritzburg, South Africa. Soil samples adjacent to faecal collection sites and faeces from a domestic herbivore, the Nguni cow, were included as controls. Hydrolase and dehydrogenase activity in faecal matter and soil samples were measured by the fluorescein diacetate and the triphenyltetrazolium chloride assay. Viable counts and counts for amylase, cellulase, esterase and protease producers were established using plate count agar and solid media containing cellulose, skim milk, starch and Tween 80. Zebra droppings produced the highest hydrolase and dehydrogenase activity. Faecal matter of the three indigenous herbivores generally produced higher hydrolytic activity than Nguni cow faeces and soil controls, thereby confirming that these materials are potential targets for hydrolytic enzyme mining.

Potential of Using Maize Cobs in Pig Diets - A Review

The quest to broaden the narrow range of feed ingredients available to pig producers has prompted research on the use of low cost, unconventional feedstuffs, which are typically fibrous and abundant. Maize cobs, a by-product of a major cereal grown worldwide, have potential to be used as a pig feed ingredient. Presently, maize cobs are either dumped or burnt for fuel. The major challenge in using maize cobs in pig diets is their lignocellulosic nature (45% to 55% cellulose, 25% to 35% hemicellulose, and 20% to 30% lignin) which is resistant to pigs' digestive enzymes. The high fiber in maize cobs (930 g neutral detergent fiber/kg dry matter [DM]; 573 g acid detergent fiber/kg DM) increases rate of passage and sequestration of nutrients in the fiber reducing their digestion. However, grinding, heating and fermentation can modify the structure of the fibrous components in the maize cobs and improve their utilization. Pigs can also extract up to 25% of energy maintenance requirements from fermentation products. In addition, dietary fiber improves pig intestinal health by promoting the growth of lactic acid bacteria, which suppress proliferation of pathogenic bacteria in the intestines. This paper reviews maize cob composition and the effect on digestibility of nutrients, intestinal microflora and growth performance and proposes the use of ensiling using exogenous enzymes to enhance utilization in diets of pigs.

Effects of porcine reproductive and respiratory syndrome virus on pig growth, diet utilization efficiency, and gas release from stored manure

The objectives of this study were to examine the effects of porcine reproductive and respiratory syndrome virus (PRRSV) infection and vaccination on pig growth, dietary nutrient efficiency of utilization, manure output, and emissions of CO, CH, HS, NO, and NH gases from stored manure. Forty-eight pigs, aged 21 d at the start of the study, were subjected to 1 of 4 treatment combinations arranged in a 2 × 2 factorial design with main factors of PRRSV vaccination and PRRSV infection. Body weight, ADFI, manure output, and nutrient efficiency of utilization were assessed and gas emissions from stored manure were determined daily from 50 to 78 d of age and for 24 d after completion of the animal phase. Infection with PRRSV markedly reduced final BW, ADG, and ADFI ( < 0.01) and reduced efficiencies of ADF and ether extract utilization ( = 0.05 and = 0.02, respectively) regardless of vaccination status. No significant treatment effects were found on manure output, manure pH, efficiencies of lignin utilization, and N retention. Infecting pigs with PRRSV increased daily manure CO emission per pig ( = 0.01). There was an interaction between immunization and infection for NO per pig with manure from uninfected, vaccinated pigs producing as much as the manure from infected, vaccinated pigs whereas there was a difference by PRRSV infection state for nonvaccinated pigs. There were also interactions between treatments for HS and NO emissions per kilogram of manure volatile solids excreted ( = 0.01 and = 0.0001, respectively) with the same pattern as for NO per pig; that is, the vaccinated pigs had similar rates of emission regardless of infection state. Pigs infected with PRRSV increased NO nitrogen per kilogram of total N excreted compared with noninfected groups ( = 0.03). Collectively, these results indicated that PRRSV infection caused decreased growth rates and nutrient utilization efficiency and increased gas emissions from stored manure.

NMR-based metabolomics highlights differences in plasma metabolites in pigs exhibiting diet-induced differences in adiposity

PURPOSE

A better understanding of the control of body fat mass and distribution is required for both human health and animal production. The current study investigates plasma parameters in response to changes in body fat mass.

METHODS

Pigs from two lines divergently selected for residual feed intake were fed diets contrasted in energy sources and nutrients. Between 74 and 132 days of age, pigs (n = 12 by diet and by line) received isoproteic and isoenergetic diets, either rich in starch (LF) or in lipids and fibres (HF). At the end of the feeding trial, plasma samples were analysed by (1)H NMR spectroscopy and standard hormonal and biochemical assays.

RESULTS

Pigs fed the HF diet had lower (P < 0.01) perirenal and subcutaneous adipose tissue relative masses than pigs fed the LF diet. Metabolomic approach showed a clear discrimination between diets, with lower (P < 0.05) plasma levels of creatinine-lysine, creatine, tyrosine, proline, histidine, lysine, phenylalanine and formate but higher (P < 0.001) plasma VLDL-LDL levels in HF pigs than in LF pigs. Plasma concentrations of triglycerides were higher (P < 0.001), while plasma concentrations of β-hydroxybutyrate, leptin, glucose, insulin and urea were lower (P ≤ 0.05) in HF pigs than in LF pigs. Plasma levels of leptin, creatine and urea were positively correlated (r = 0.3, P < 0.05) with relative adipose tissue masses.

CONCLUSION

These data indicate that metabolites associated with energy and protein metabolism were involved in the response to a high-fat, high-fibre diet. Relevant plasma indicators of metabolic flexibility related to changes in body adiposity were then proposed.

Evaluation of inclusion level of wheat distillers dried grains with solubles with and without protease or β-mannanase on performance and water intake of turkey hens

It is becoming a common practice to use higher levels of wheat distillers dried grains with solubles (wDDGS) in poultry diets. The objective of this study was to determine the effects of level of inclusion of wDDGS with or without enzyme (E-, i.e., wDDGSE-) supplementation on performance and water consumption of turkey hens (0 to 72 d). Two diets (0 or 30% wDDGS) were formulated to meet the nutrient requirements of Hybrid Converter turkeys. Diets (0 or 30% wDDGS; starter, grower, and finisher) were then blended to obtain a different level of inclusion (15%) of wDDGS. The 30% wDDGS diet was divided into 3 fractions and 2 fractions supplemented with either protease (P+, i.e., wDDGSP+; 0.126 g/kg) or β-mannanase (M+, i.e., wDDGSM+; 0.05 g/kg). All 5 diets were fed ad libitum as mash. The 700 0-d turkey hens were randomly allocated into groups of 35 birds per replicate with 4 replicate floor pens per treatment, in a completely randomized design. Water consumption per pen was recorded beginning at 7 d. There was no effect of dietary treatment on feed intake. BW of turkey hens (52 d; grower) was significantly higher for 30% wDDGSP+ as compared to 0% wDDGSE- or 15% wDDGSE- diets; but was not different from 30% wDDGSE- or 30% wDDGSM+ diets. FCR (P < 0.01; 28 to 52 d), and total FCR (P < 0.05; 0 to 72 d) was significantly improved for birds fed 15 or 30% wDDGS regardless of enzyme treatment compared to 0% wDDGSE-. Water intake (WI, in mL per bird per day) tended to be higher (P = 0.08) between 7 and 28 d for 30% wDDGSP+ diets compared to other treatments. Similarly, WI of birds fed 30% wDDGSP+ was higher (P < 0.05; 28 to 52 and 52 to 72 d) and total WI (P = 0.07; 7 to 72 d) tended to be higher than other treatments. This study is the first to report the impact of wDDGS on WI. As high as 30% wDDGS can be substituted in turkey hen diets. No effect of P+ or M+ at the inclusion level tested was found on performance.

The effects of extrusion of wheat distillers dried grains with solubles with or without an enzyme cocktail on performance of turkey hen poults

Two experiments were conducted to determine if extrusion (EX) or enzymes (E) could overcome the restrictions (e.g., high fiber) of feeding wheat distillers dried grain with solubles (wDDGS) and improve its nutritional value for feeding turkeys. Two starter diets with either 0 or 30% wDDGS were formulated to meet or exceed the nutrient requirements of the Hybrid Converter female turkeys. The 30% wDDGS diet was substituted with either non-extruded (EX-) or extruded (EX+) wDDGS to produce three basal diets [0% wDDGS (EX-) or 30% wDDGS (EX-/EX+)]. Diets were blended to obtain 15% wDDGS. In the respective treatments, only wDDGS was extruded (temperature; 118°C, retention; 15 sec, total moisture; 25% and pressure 33 bar). The respective experimental diets were supplemented with/without an enzyme cocktail (E; 0.5 g/kg). Test diets were fed from 7-21 d in a completely randomized design. In Experiment 1, a total of 210 turkey hen poults were fed diets containing 0, 15, or 30% wDDGS (EX-) with or without enzyme (E+/E-). Body weight (BW) and feed intake (FI) were significantly higher for 0% wDDGSE-. Nitrogen retention (NR) and apparent metabolizable energy (AME) for the 30% wDDGSE- was significantly higher than other treatments at 21 d. The results indicated significant main effects of E and an interaction between wDDGS level and E. In Experiment 2, 280 turkey hen poults were fed 8 diets [15/30% wDDGS (E+/E-), (EX-/EX+)]. The level of wDDGS had a significant effect on BW, FI and gain:feed; 15% inclusion was superior to 30%. There were significant 2- and 3-way interactions for AME and NR at 21 d due to differences in enzyme response with 15 or 30% wDDGS inclusion and/or extrusion of wDDGS. As high as 15% wDDGS can be incorporated in turkey hen diets. There were no beneficial effects of EX or E on poult performance.