EFFECT OF FEEDING WET DISTILLERS GRAINS WITH SOLUBLES TO BEEF CATTLE ON AIR AND MANURE QUALITY

Air quality is becoming a pressing issue for beef feedlot producers. Feeding practices influence the excretion of starch, fiber, nitrogen (N), and sulfur (S) in manure, thereby affecting nutrient content and the production of ammonia (NH3) and odorous compounds. Wet distillers grains with solubles (WDGS) are a common and economical ingredient in feedlot diets. WDGS are high in protein, fiber, phosphorus (P), and S but low in starch. The objective of this study was to compare NH3 concentration in the air and nutrients and volatile organic compounds (VOC) concentration in manure between two dietary treatments fed to feedlot cattle. Five pens of feedlot cattle were fed diets containing 14% to 35% WDGS and five pens were fed a corn-based diet with no ethanol byproducts (Control). Each pen had twelve sampling locations (N = 120) where air and manure samples were collected from the feedlot surface. Air samples were analyzed for NH3 concentration. Manure samples were analyzed for dry matter, pH, volatile solids, VOC, and nutrient composition (N, P, and S). Concentrations of P and S in manure and NH3 in the air were higher in pens fed WDGS compared to pens fed the control diet. Concentrations of VOC were similar across both treatments

Bacteroides fragilis requires the ferrous-iron transporter FeoAB and the CobN-like proteins BtuS1 and BtuS2 for assimilation of iron released from heme

The intestinal commensal and opportunistic anaerobic pathogen Bacteroides fragilis has an essential requirement for both heme and free iron to support growth in extraintestinal infections. In the absence of free iron, B. fragilis can utilize heme as the sole source of iron. However, the mechanisms to remove iron from heme are not completely understood. In this study, we show that the inner membrane ferrous iron transporter ∆feoAB mutant strain is no longer able to grow with heme as the sole source of iron. Genetic complementation with the feoAB gene operon completely restored growth. Our data indicate that iron is removed from heme in the periplasmic space, and the released iron is transported by the FeoAB system. Interestingly, when B. fragilis utilizes iron from heme, it releases heme-derived porphyrins by a dechelatase activity which is upregulated under low iron conditions. This is supported by the findings showing that formation of heme-derived porphyrins in the ∆feoAB mutant and the parent strain increased 30-fold and fivefold (respectively) under low iron conditions compared to iron replete conditions. Moreover, the btuS1 btuS2 doublemutant strain (lacking the predicted periplasmic, membrane anchored CobN-like proteins) also showed growth defect with heme as the sole source of iron, suggesting that BtuS1 and BtuS2 are involved in heme-iron assimilation. Though the dechelatase mechanism remains uncharacterized, assays performed in bacterial crude extracts show that BtuS1 and BtuS2 affect the regulation of the dechelatase-specific activities in an iron-dependent manner. These findings suggest that the mechanism to extract iron from heme in Bacteroides requires a group of proteins, which spans the periplasmic space to make iron available for cellular functions

The role of flavor and fragrance chemicals in TRPA1 (transient receptor potential cation channel, member A1) activity associated with allergies

TRPA1 has been proposed to be associated with diverse sensory allergic reactions, including thermal (cold) nociception, hearing and allergic inflammatory conditions. Some naturally occurring compounds are known to activate TRPA1 by forming a Michael addition product with a cysteine residue of TRPA1 through covalent protein modification and, in consequence, to cause allergic reactions. The anti-allergic property of TRPA1 agonists may be due to the activation and subsequent desensitization of TRPA1 expressed in sensory neurons. In this review, naturally occurring TRPA1 antagonists, such as camphor, 1,8-cineole, menthol, borneol, fenchyl alcohol and 2-methylisoborneol, and TRPA1 agonists, including thymol, carvacrol, 1’S-1’- acetoxychavicol acetate, cinnamaldehyde, α-n-hexyl cinnamic aldehyde and thymoquinone as well as isothiocyanates and sulfides are discussed