Invited Review: From nose to gut - the role of the microbiome in neurological disease.

Inflammation and neurodegeneration are key features of many chronic neurological diseases, yet the causative mechanisms underlying these processes are poorly understood. There has been mounting interest in the role of the human microbiome in modulating the inflammatory milieu of the central nervous system (CNS) in health and disease. To date, most research has focussed on a gut-brain axis, with other mucosal surfaces being relatively neglected. We herein take the novel approach of comprehensively reviewing the roles of the microbiome across several key mucosal interfaces - the nose, mouth, lung and gut - in health and in Parkinson's disease (PD), Alzheimer's disease (AD) and multiple sclerosis (MS). This review systematically appraises the anatomical and microbiological landscape of each mucosal surface in health and disease before considering relevant mechanisms that may influence the initiation and progression of PD, AD and MS. The cumulative effects of dysbiosis from the nose to the gut may contribute significantly to neurological disease through a wide variety of mechanisms, including direct translocation of bacteria and their products, and modulation of systemic or CNS-specific immunity. This remains an understudied and exciting area for future research and may lead to the development of therapeutic targets for chronic neurological disease.

Evaluation of two mycotoxin mitigation strategies in grow-finish swine diets containing corn dried distillers grains with solubles naturally contaminated with deoxynivalenol.

A total of 1,040 growing pigs (initially, 22.9 ± 4.3 kg) were used in a 115-d study to evaluate the effects of 2 mycotoxin mitigation strategies, a preservative blend (PB) and a yeast product (YP), on the growth performance of swine fed diets containing corn dried distillers grains with solubles naturally contaminated with deoxynivalenol (DON). The PB consists of preservatives, antioxidants, AA, and direct-fed microbials and is included in diets to help pigs cope with the toxic effects of ingested mycotoxins. The YP works as an adsorbent to bind and prevent the absorption of mycotoxins in the gastrointestinal tract. Pigs were allotted to pens by initial BW and sex; pens were then assigned to treatments in a randomized block design with initial BW and sex serving as the blocking factors. Pens were randomly allotted to 1 of 4 dietary treatments consisting of a positive control (PC) containing <1 mg kg(-1) DON, a negative control (NC) formulated to contain 4 mg kg(-1) DON, NC with PB, and NC with YP. From d 0 to 42 and 42 to 84, no effect of diets containing PB or YP were observed for any of the growth criteria evaluated. From d 84 to 115, pigs fed PC or diets containing PB had improved (P < 0.05) ADG compared to pigs fed NC or diets containing YP, whereas pigs fed YP had improved (P < 0.05) ADG compared to those fed NC. Pigs fed diets containing PB or YP had improved (P < 0.05) ADFI and G:F compared to pigs fed NC. Overall (d 0 to 115), pigs fed diets containing PB had improved (P < 0.05) ADG, ADFI, and G:F compared to pigs fed NC. These results indicate that PB may be a suitable mycotoxin mitigation strategy in growing swine fed diets naturally contaminated with DON.

The use of a covariate reduces experimental error in nutrient digestion studies in growing pigs.

Covariance analysis limits error, the degree of nuisance variation, and overparameterizing factors to accurately measure treatment effects. Data dealing with growth, carcass composition, and genetics often use covariates in data analysis. In contrast, nutritional studies typically do not. The objectives of this study were to 1) determine the effect of feeding diets containing dehulled, degermed corn, corn-soybean meal, or distillers dried grains with solubles on nutrient digestibility coefficients, 2) evaluate potential interactive effects between initial and final treatment diets on the final treatment diet effects, and 3) determine if initial criterion (digestibility or physiological values) would effectively correct for variation among pigs that could thereby affect final treatment diet digestibility coefficients. Seventy-two crossbred barrows [(Yorkshire × Landrace × Duroc) × Chester White] were randomly assigned to 1 of the 3 diets within initial dietary treatment for Phase-2 (P2; 14 d). Fecal and blood samples were collected after feeding the Phase-1 (P1) diets for 14 d (trial d-14) and on d 28 after feeding the P2 diets for 14 d. Fecal samples were dried and analyzed for C, ether extract, GE, N, NDF, P, and S. Plasma samples were analyzed for plasma urea N and triacylglycerides. Pigs were fed diets that differed widely in CP, NDF, and P, resulting in an overall decrease in C, GE, NDF, N, P, and S digestibility and plasma urea N and triacylglycerides as dietary fiber increased in P1 and P2 (P < 0.10). There were no differences in P2 criteria due to blocking for the P1 diet. There tended (P = 0.10 to 0.20) to be P1 × P2 interactions for NDF and S, indicating that the response of pigs to the P2 diet may depend on the P1 diet. In contrast, when the P1 variable was used as a covariate for P2 data, it was statistically significant for GE, NDF, N, S, and plasma urea N (P < 0.10) whereas C and ether extract showed tendencies but not for P digestibility or plasma triacylglycerides. In conclusion, if initial diets are known, subsequent treatments should be balanced for the initial diet because of potential of initial diet × final diet interactions. If the initial diets are not known, then the initial digestibility coefficient would be effective in reducing the variation associated with subsequently obtained data and should be considered as a covariate in future grower-finisher swine digestibility research.

Effects of drying methods on nitrogen and energy concentrations in pig feces and urine, and poultry excreta.

Accurate estimations of nutrient digestion and retention are critical in nutrient balance and feed evaluation studies because errors that occur are often additive. However, there is no standard universal method for drying feces, urine, or excreta before laboratory analysis. The objective of this study was to evaluate the impact of 4 different drying methods on nutrient concentrations in feces, urine, and excreta. Twelve individually penned growing pigs were fed 1 of 3 diets and 16 pens of 10 growing broilers were fed 1 of 4 diets that differed in NDF and CP. Feces, urine, and excreta that varied in nutrient composition were collected after 7 d of diet adaptation. Samples were dried using 1 of 4 methods: undried (UD), freeze-dried (FD), oven-dried at 55 °C for 48 h (OD55), or oven-dried at 100 °C for 48 h (OD100), after which DM, GE, N, C, and S were determined. In swine feces, drying resulted in a loss of GE (P < 0.10) and S (P < 0.01) by 5 and 58%, respectively, compared with UD feces. There was no difference (P ≥ 0.36) among drying method on DM, GE, N, C, or S concentrations. There were no differences (P ≥ 0.12) in urinary GE due to drying or between drying methods; however, urinary DM was greatest by FD compared with OD (P < 0.05) and greater for OD55 compared with OD100 (P < 0.01). In poultry excreta, GE (P < 0.05), N (P < 0.10), and S (P < 0.01) were reduced by drying by an average of 6, 10, and 66%, respectively. There were no differences (P ≥ 0.50) among drying methods except FD excreta had a greater S concentration than OD (P < 0.10). Regardless of drying method, some GE and N loss appears to be inevitable, but there is no apparent advantage between FD and OD. The apparent greater S losses warrant further investigation.