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Infection with the foodborne pathogen Campylobacter is the leading bacterial cause of human foodborne illness in the United States. The objectives of this experiment were to test the hypothesis that mixed microbial populations from the bovine rumen may be better at excluding Campylobacter than populations from freshly voided feces and to explore potential reasons as to why the rumen may be a less favorable environment for Campylobacter than feces. In an initial experiment, C. jejuni cultures inoculated without or with freshly collected bovine rumen fluid, bovine feces or their combination were cultured micro-aerobically for 48 h. Results revealed that C. jejuni grew at similar growth rates during the first 6 h of incubation regardless of whether inoculated with the rumen or fecal contents, with rates ranging from 0.178 to 0.222 h -1 . However, C. jejuni counts (log 10 colony-forming units/mL) at the end of the 48 h incubation were lowest in cultures inoculated with rumen fluid (5.73 log 10 CFUs/mL), intermediate in cultures inoculated with feces or both feces and rumen fluid (7.16 and 6.36 log 10 CFUs/mL) and highest in pure culture controls that had not been inoculated with the rumen or fecal contents (8.32 log 10 CFUs/mL). In follow-up experiments intended to examine the potential effects of hydrogen and hydrogen-consuming methanogens on C. jejuni , freshly collected bovine feces, suspended in anaerobic buffer, were incubated anaerobically under either a 100% carbon dioxide or 50:50 carbon dioxide/hydrogen gas mix. While C. jejuni viability decreased <1 log 10 CFUs/mL during incubation of the fecal suspensions, this did not differ whether under low or high hydrogen accumulations or whether the suspensions were treated without or with the mechanistically distinct methanogen inhibitors, 5 mM nitrate, 0.05 mM 2-bromosulfonate or 0.001 mM monensin. These results suggest that little if any competition between C. jejuni and hydrogen-consuming methanogens exists in the bovine intestine based on fecal incubations.

Foodborne pathogen Campylobacter jejuni has been associated with ruminants. The objectives of this experiment were to determine C. jejuni survivability in mixed in vitro rumen microbial populations and the impact on methane production with or without methane inhibitors 2-bromosulfonate (BES) and/or sodium nitrate. When inoculated into rumen microbial populations without or with 0.5 mM BES, 5.0 mM nitrate or their combination, C. jejuni viability decreased from 4.7 ± 0.1 log 10 colony forming units (CFU)/mL after 24 h. Loss of C. jejuni viability was greater ( P  < 0.05) when incubated under 100% CO 2 compared to 50% H 2 :50% CO 2 , decreasing 1.46 versus 1.15 log units, respectively. C. jejuni viability was also decreased ( P  < 0.05) by more than 0.43 log units by the anti-methanogen treatments. Rumen microbial populations produced less methane ( P  = 0.05) when incubated with than without C. jejuni regardless of whether under 100% CO 2 or 50% H 2 :50% CO 2 . For either gas phase, nitrate was decreased (13.2 versus 37.9%) by the anti-methanogen treatments versus controls although not always significant. C. jejuni -inoculated populations metabolized 16.4% more ( P  < 0.05) nitrate under H 2 :CO 2 versus 100% CO 2 . Apparently, C. jejuni can compete for H 2 with methanogens but has limited survivability under rumen conditions.

We design, fabricate, and characterize a multilayer nanophotonic structure that couples light from standard optical fiber to an integrated photonics chip with unprecedented efficiency. The structure comprises a multilayer waveguide array tapering into a single waveguide supporting only fundamental TE- and TM-like modes. Measurements reveal a record-setting fiber-to-chip coupling efficiency of ${98.3}\% \;{\pm}\;{0.3}\%$ per facet at a 1575 nm wavelength that remains greater than ${92.8}\% \;{\pm}\;{0.4}\%$ across the 1550-1600 nm wavelength range. This approach is tailorable to any material platform, fiber type, or operating wavelength and represents a significant step forward for the accessibility of integrated photonics.

Lipolysis and biohydrogenation in ruminal animals promote the accumulation of saturated fatty acids in their meat and milk. Antibodies were generated against key ruminal lipase contributors Anaerovibrio lipolyticus, Butyrivibrio fibrisolvens, Propionibacterium avidum and acnes. An anti-Pseudomonas lipase antibody was generated to determine if an antibody against a purified protein would be more effective. Each bacterium was cultured and assayed without or with increasing levels of each antibody. Butyrivibrio fibrisolvens H17C also participates in biohydrogenation and therefore the antibody was tested to determine if it could effectively reduce biohydrogenation. Butyrivibrio fibrisolvens was assayed without and with the anti-B. fibrisolvens antibody and linoleic or α-linolenic acid. All antibodies were effective at reducing lipolysis with the anti-Pseudomonas lipase averaging a 78% reduction. The anti-B. fibrisolvens showed a tendency for a reduction (P=0.0713) in biohydrogenation products of α-linolenic acid. Results demonstrate that lipolysis and biohydrogenation can be immunologically inhibited in vitro., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The emergence and growth of transformation optics over the past decade has revitalized interest in how a gradient refractive index (GRIN) can be used to control light propagation. Two-dimensional demonstrations with lithographically defined silicon (Si) have displayed the power of GRIN optics and also represent a promising opportunity for integrating compact optical elements within Si photonic integrated circuits. Here, we demonstrate the fabrication of three-dimensional Si-based GRIN micro-optics through the shape-defined formation of porous Si (PSi). Conventional microfabrication creates Si square microcolumns (SMCs) that can be electrochemically etched into PSi elements with nanoscale porosity along the shape-defined etching pathway, which imparts the geometry with structural birefringence. Free-space characterization of the transmitted intensity distribution through a homogeneously etched PSi SMC exhibits polarization splitting behavior resembling that of dielectric metasurfaces that require considerably more laborious fabrication. Coupled birefringence/GRIN effects are studied by way of PSi SMCs etched with a linear (increasing from edge to center) GRIN profile. The transmitted intensity distribution shows polarization-selective focusing behavior with one polarization focused to a diffraction-limited spot and the orthogonal polarization focused into two laterally displaced foci. Optical thickness-based analysis readily predicts the experimentally observed phenomena, which strongly match finite-element electromagnetic simulations.

A deterministic graphene-sandwiched Li-ion battery electrode consisting of an integrated 3D mesostructure of electrochemically active materials and graphene is presented. As demonstrations, electrodes with active nanomaterials that coat (V2 O5 @graphene@V2 O5 cathode) or are coated by (graphene@Si@graphene anode) graphene are fabricated. These electrodes exhibit high capacities and ultralong cycle lives (the cathode can be cycled over 2000 times with minimal capacity fade)., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Many procedures in modern clinical medicine rely on the use of electronic implants in treating conditions that range from acute coronary events to traumatic injury. However, standard permanent electronic hardware acts as a nidus for infection: bacteria form biofilms along percutaneous wires, or seed haematogenously, with the potential to migrate within the body and to provoke immune-mediated pathological tissue reactions. The associated surgical retrieval procedures, meanwhile, subject patients to the distress associated with re-operation and expose them to additional complications. Here, we report materials, device architectures, integration strategies, and in vivo demonstrations in rats of implantable, multifunctional silicon sensors for the brain, for which all of the constituent materials naturally resorb via hydrolysis and/or metabolic action, eliminating the need for extraction. Continuous monitoring of intracranial pressure and temperature illustrates functionality essential to the treatment of traumatic brain injury; the measurement performance of our resorbable devices compares favourably with that of non-resorbable clinical standards. In our experiments, insulated percutaneous wires connect to an externally mounted, miniaturized wireless potentiostat for data transmission. In a separate set-up, we connect a sensor to an implanted (but only partially resorbable) data-communication system, proving the principle that there is no need for any percutaneous wiring. The devices can be adapted to sense fluid flow, motion, pH or thermal characteristics, in formats that are compatible with the body's abdomen and extremities, as well as the deep brain, suggesting that the sensors might meet many needs in clinical medicine.

Thymol is a natural product that exhibits antimicrobial activity in vitro but in vivo results indicate that absorption within the proximal alimentary tract precludes its delivery to the distal gut. Presently, the anti-Campylobacter activity of thymol was compared against that of thymol-β-D-glucopyranoside, the latter being resistant to absorption. When treated with 1 mM thymol, Campylobacter coli and jejuni were reduced during pure or co-culture with a β-glycoside-hydrolysing Parabacteroides distasonis. Thymol-β-D-glucopyranoside treatment (1 mM) did not reduce C. coli and jejuni during pure culture but did during co-culture with P. distasonis or during mixed culture with porcine or bovine faecal microbes possessing β-glycoside-hydrolysing activity. Fermentation acid production was reduced by thymol-β-D-glucopyranoside treatment, indicating that fermentation was inhibited, which may limit its application to just before harvest. Results suggest that thymol-β-D-glucopyranoside or similar β-glycosides may be able to escape absorption within the proximal gut and become activated by bacterial β-glycosidases in the distal gut., (Published by Elsevier Ltd.)

The hydrolysis of free fatty acids from lipids is a prerequisite for biohydrogenation, a process that effectively saturates free fatty acids. Anaerovibrio lipolyticus 5s and Butyrivibrio fibrisolvens have long been thought to be the major contributors to ruminal lipolysis; however, Propionibacterium avidum and acnes recently have been identified as contributing lipase activity in the rumen. In order to further characterize the lipase activity of these bacterial populations, each was grown with three different lipid substrates, olive oil, corn oil, and flaxseed oil (3 %). Because different finishing rations contain varying levels of glycogen (a source of free glucose) this study also documented the effects of glucose on lipolysis. P. avidum and A. lipolyticus 5s demonstrated the most rapid rates (P < 0.05) of lipolysis for cultures grown with olive oil and flaxseed oil, respectively. A. lipolyticus, B. fibrisolvens, and P. avidum more effectively hydrolyzed flaxseed oil than olive oil or corn oil, especially in the presence of 0.02 % glucose. Conversely, P. acnes hydrolyzed corn oil more readily than olive oil or flaxseed oil and glucose had no effect on lipolytic rate. Thus, these bacterial species demonstrated different specificities for oil substrates and different sensitivities to glucose.

Because challenge models to infect peripheral lymph nodes (PLNs) with Salmonella have not been reported, we performed a series of experiments to develop and refine challenge models to evaluate an intervention applied at the animal level and to provide initial estimates of efficacy of an intervention (i.e., a vaccine) to aid in the design of future studies. In each of four experiments, steers (control or vaccinated) were inoculated with Salmonella strains Montevideo or Newport, and in experiment IV, Salmonella Senftenberg was also used. Calves were euthanized 14 to 42 days postinoculation, and PLNs were collected. In the first experiment, calves were challenged with ∼10¹⁰ Salmonella cells, and few treatment differences were observed 14 days postchallenge. However, by day 21, Salmonella Newport was recovered from fewer vaccinated calves than control calves (P < 0.05). In experiment II, calves were challenged with ∼10⁷ Salmonella cells and, after two necropsies (14 and 28 days postchallenge), only one lymph node was Salmonella positive; therefore, the study was terminated. In experiment III, calves were again challenged with ∼10¹⁰ Salmonella cells, and no significant effect of vaccine was observed in calves challenged with Montevideo or Newport strains. A transdermal route of challenge was explored in experiment IV, using a 10-lancet, allergy testing instrument. Sixteen steers were challenged with either Salmonella Newport or Salmonella Montevideo (Salmonella Newport right legs; Salmonella Montevideo left legs), and all steers were challenged on the lower abdomen with Salmonella Senftenberg. Transdermal inoculation resulted in predictably Salmonella-positive PLNs, and a modest vaccine effect was detected. Because it is well tolerated by the calves and results in predictable and regionally specific Salmonella recovery from PLNs, the transdermal route of challenge may be preferred by researchers wishing to evaluate the impact of interventions designed to reduce the carriage of Salmonella in PLNs.

Food-producing animals are reservoirs of Campylobacter, a leading bacterial cause of human foodborne illness. The natural product thymol can reduce the survivability of Campylobacter, but its rapid absorption in the proximal gastrointestinal tract may preclude its use as a feed additive to reduce intestinal colonization of these pathogens. This work examined the ex vivo absorption of thymol and thymol-β-d-glucopyranoside in everted porcine jejunal segments, as the latter was hypothesized to be more resistant to absorption. A modified gas chromatography and extraction method was developed to determine 1.0-500 mg/L thymol. From 1 and 3 mM solutions, 0.293 ± 0.04 and 0.898 ± 0.212 mM thymol, respectively, p = 0.0347, were absorbed, and 0.125 ± 0.041 and 0.317 ± 0.143 mM thymol-β-d-glucopyranoside, respectively, p = 0.0892, were absorbed. Results indicate that thymol-β-d-glucopyranoside was absorbed 2.3 to 2.8 times less effectively than thymol, thus providing evidence that thymol-β-d-glucopyranoside may potentially be used as a feed additive to transport thymol to the piglet lower gut.

Supplemental glycerol inhibits rumen lipolysis, a prerequisite for rumen biohydrogenation, which is responsible for the saturation of dietary fatty acids consumed by ruminant animals. Feeding excess glycerol, however, adversely affects dry matter digestibility. To more clearly define the effect of supplemental glycerol on rumen lipolysis, mixed populations of ruminal bacteria were incubated with 6 or 20% glycerol (vol/vol). After 48-h anaerobic incubation of mixed culture rumen fluid, rates of free fatty acid production (nmol/mL per h) for the 6 and 20% glycerol-supplemented samples were decreased by 80 and 86%, respectively, compared with rates from nonsupplemented control cultures (12.4±1.0; mean ± SE). Conversely, assay of the prominent ruminal lipase-producing bacteria Anaerovibrio lipolyticus 5S, Butyrivibrio fibrisolvens 49, and Propionibacterium species avidum and acnes revealed no effect of 2 or 10% (vol/vol) added glycerol on lipolytic activity by these organisms. Supplementing glycerol at 6% on a vol/vol basis, equivalent to supplementing glycerol at approximately 8 to 15% of diet dry matter, effectively reduced lipolysis. However, the mechanism of glycerol inhibition of ruminal lipolysis remains to be demonstrated., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Strategies are sought to reduce intestinal colonisation of food-producing animals by Campylobacter jejuni, a leading bacterial cause of human foodborne illness worldwide. Presently, we tested the antimicrobial activity of hydrolysable-rich blackberry, cranberry and chestnut tannin extracts and condensed tannin-rich mimosa, quebracho and sorghum tannins (each at 100 mg/mL) against C. jejuni via disc diffusion assay in the presence of supplemental casamino acids. We found that when compared to non-tannin-treated controls, all tested tannins inhibited the growth of C. jejuni and that inhibition by the condensed tannin-rich mimosa and quebracho extracts was mitigated in nutrient-limited medium supplemented with casamino acids. When tested in broth culture, both chestnut and mimosa extracts inhibited growth of C. jejuni and this inhibition was much greater in nutrient-limited than in full-strength medium. Consistent with observations from the disc diffusion assay, the inhibitory activity of the condensed tannin-rich mimosa extracts but not the hydrolysable tannin-rich chestnut extracts was mitigated by casamino acid supplementation to the nutrient-limited medium, likely because the added amino acids saturated the binding potential of the condensed tannins. These results demonstrate the antimicrobial activity of various hydrolysable and condensed tannin-rich extracts against C. jejuni and reveal that condensed tannins may be less efficient than hydrolysable tannins in controlling C. jejuni in gut environments containing high concentrations of amino acids and soluble proteins.

Food producing animals can be reservoirs of Campylobacter, a leading bacterial cause of human foodborne illness. Campylobacter spp. utilize amino acids as major carbon and energy substrates, a process that can be inhibited by thymol and diphenyliodonium chloride (DIC). To determine the effect of these potential additives on feed intake, live weight gain, and gut Campylobacter levels, growing pigs were fed standard grower diets supplemented with or without 0.0067 or 0.0201% thymol or 0.00014 or 0.00042% DIC in a replicated study design. Diets were offered twice daily for 7 days, during which time daily feed intake (mean ± SEM, 2.39 ± 0.06 kg day(-1)) and daily gain (0.62 ± 0.04 kg day(-1)) were unaffected (P > 0.05) by treatment. Pigs treated with DIC but not thymol tended to have lower rectal Campylobacter levels (P ∼ 0.07) (5.2 versus 4.2 and 4.4 log CFU g(-1) rectal contents for controls and 0.00014% DIC and 0.00042% DIC, respectively; SEM ∼ 0.26). However, DIC or thymol treatments did not affect (P > 0.05) ileal or cecal Campylobacter (1.6 ± 0.17 and 4.5 ± 0.26 log CFU g(-1), respectively), cecal total culturable anaerobes (9.8 ± 0.10 log CFU g(-1)), or accumulations of major fermentation end products within collected gut contents. These results suggest that thymol and DIC were appreciably absorbed, degraded, or otherwise made unavailable in the proximal alimentary tract and that encapsulation technologies will likely be needed to deliver effective concentrations of these compounds to the lower gut to achieve in vivo reductions of Campylobacter.

The objective of the current research was to determine if feeding the citrus by-products(D) -limonene (DL) and citrus molasses would reduce the concentration and prevalence of Salmonella in weanling pigs experimentally infected with Salmonella Typhimurium. Twenty crossbred weanling pigs (average body weight [BW], 19.9 kg) were randomly assigned to one of four treatments: control, low-dose DL (1.5 ml/kg of BW per day), high-dose DL (3.0 ml/kg of BW per day), and citrus molasses (0.05 kg/kg of BW per day). Treatments were administered in the feed (twice daily) for 7 days, with one-half of the dose administered at each feeding. Fecal samples were collected twice daily (prior to administration of treatment) and cultured for quantitative and qualitative determination of the challenge strain of Salmonella. Upon termination of the study, pigs were euthanized and tissues from the stomach, ileum, cecum, spiral colon, and rectum, as well as luminal contents, were collected. In addition, the popliteal and ileocecal lymph nodes and liver, spleen, and tonsil tissue were collected for qualitative Salmonella culture. No significant treatment differences (P > 0.05) were observed among treatments for fecal concentration or prevalence of Salmonella throughout the 7-day collection period. Likewise, no treatment differences (P > 0.05) were observed for any of the tissue or luminal content samples collected. Salmonella was not cultured from the muscle-bound popliteal lymph node but was cultured from the mesenteric ileocecal lymph nodes. While there were no effects in the current experiment, future research may examine the effect of a lower challenge dose and/or different administration (dose or duration) of the citrus by-products.

Foodborne pathogenic bacteria such as Escherichia coli O157:H7 are threats to the safety of beef. Citrus peel and dried orange pulp are by-products from citrus juice production that have natural antimicrobial effects and are often incorporated into least-cost ration formulations for beef and dairy cattle. This study was designed to determine if orange peel and pulp affected E. coli O157:H7 populations in vivo. Sheep (n = 24) were fed a cracked corn grain-based diet that was supplemented with a 50-50 mixture of dried orange pellet and fresh orange peel to achieve a final concentration (dry matter basis, wt/wt) of 0, 5, or 10% pelleted orange peel (OP) for 10 days. Sheep were artificially inoculated with 10(10) CFU of E. coli O157:H7 by oral dosing. Fecal shedding of E. coli O157:H7 was measured daily for 5 days after inoculation, after which all animals were humanely euthanized. At 96 h postinoculation, E. coli O157:H7 shedding was reduced (P < 0.05) in sheep fed 10% OP. Populations of inoculated E. coli O157:H7 were reduced by OP treatment throughout the gastrointestinal tract; however, this reduction reached significant levels in the rumen (P < 0.05) of sheep fed 10% OP diets. Cecal and rectal populations of E. coli O157:H7 were reduced (P < 0.05) by inclusion of both 5 and 10% OP diets. Our results demonstrate that orange peel products can be used as a preharvest intervention strategy as part of an integrated pathogen reduction scheme.

Strategies aimed at reducing fecal shedding of Salmonella and other foodborne pathogens may be effective for limiting transmission of pathogens from food animals to humans. The objective of this study was to determine the effectiveness of gallium maltolate (GaM) against Salmonella in vitro and to determine whether oral administration of GaM would reduce fecal shedding of Salmonella in cattle. Gallium is a semimetal exhibiting antimicrobial properties against some pathogenic bacteria, including Salmonella, by exploiting their need for iron to survive and replicate. In vitro growth studies were performed in pure cultures of Salmonella and in mixed cultures from ruminal fluid. Inclusion of GaM in culture medium or in mixed cultures of ruminal fluid resulted in a significant reduction in growth of Salmonella, suggesting that GaM may be effective for limiting growth and survival in vivo. Therefore, we subsequently administered two doses of GaM to Holstein steers, experimentally infected them with Salmonella, and quantitatively and qualitatively monitored fecal shedding at 12-h intervals. Sixty hours after beginning treatment, cattle were euthanized, and luminal contents and tissue were aseptically harvested from the rumen, jejunum, spiral colon, cecum, and rectum. The luminal contents were processed for quantitative and qualitative analysis of the challenge strains of Salmonella, and tissue samples were enriched and plated for qualitative analysis. We found no significant differences between control and treated animals in quantitative levels of Salmonella in the feces or the luminal contents. Likewise, we observed no pattern between control and treated animals in the frequency of positive or negative results from enriched feces, luminal contents, or tissue samples. These results suggest that GaM was not effective for reducing Salmonella in cattle.

Pathogenic bacteria attached to the hide or shed in the feces of cattle at slaughter can contaminate carcasses intended to be processed for human consumption. Therefore, new pre-harvest interventions are needed to prevent the carriage and excretion of foodborne pathogens in cattle presented to the processing plant. The objectives of this study were to examine the antimicrobial effects of hydrolysable tannin-rich chestnut and condensed tannin-rich mimosa extracts on bacterial indicators of foodborne pathogens when applied as a hide-intervention and as a feed additive to feedlot cattle. Water (control) or solutions (3 % wt/vol) of chestnut- and mimosa-extract treatments were sprayed (25 mL) at the left costal side of each animal to a 1000 cm² area, divided in four equal quadrants. Hide-swabs samples obtained at pre-, 2-min, 8-h, and 24-h post-spray application were cultured to enumerate Escherichia coli/total coliforms and total aerobic plate counts. In a second experiment, diets supplemented without (controls) or with (1.5 % of diet dry matter) chestnut- or mimosa-extracts were fed during a 42-day experimental feeding period. Weekly fecal samples starting on day 0, and rumen fluid obtained on days 0, 7, 21 or 42 were cultured to enumerate E.coli/total coliforms and Campylobacter. Tannin spray application showed no effect of treatment or post-application-time (P > 0.05) on measured bacterial populations, averaging 1.7/1.8, 1.5/1.6 and 1.5/1.7 (log₁₀CFU/cm²) for E. coli/total coliforms, and 4.0, 3.4 and 4.2 (log₁₀CFU/cm²) in total aerobes for control, chestnut and mimosa treatments, respectively. Mean (± SEM) ruminal E. coli and total coliform concentrations (log(10) CFU/mL) were reduced (P < 0.01) in steers fed chestnut-tannins (3.6 and 3.8 ± 0.1) in comparison with the controls (4.1 and 4.2 ± 0.1). Fecal E. coli concentrations were affected by treatment (P< 0.01), showing the highest values (log₁₀ CFU/g) in fecal contents from mimosa-fed steers compared to controls (5.9 versus 5.6 ± 0.1 SEM, respectively). Total coliforms (log CFU/g) showed the highest values (P < 0.01) in feces from chestnut- and mimosa-fed steers (6.0 and 6.1 ± 0.1 respectively) in comparison with controls (5.7 ± 0.1). Fecal Campylobacter concentrations (log₁₀CFU/g) were affected by treatment (P < 0.05), day (P < 0.001) and their interaction (P < 0.01) with the controls having lower concentrations than chestnut- and mimosa-fed steers (0.4, 1.0, and 0.8 ± 0.3, respectively). It was concluded that under our research conditions, tannins were not effective in decreasing measured bacterial populations on beef cattle hides. Additionally, chestnut tannin reduced E. coli and total coliforms within the rumen but the antimicrobial effect was not maintained in the lower gastrointestinal tract. Further research is necessary to elucidate the possible antimicrobial effects of tannins at site-specific locations of the gastrointestinal tract in beef cattle fed high-grain and high-forage diets.

Ruminant-derived foods contain high proportions of saturated fats as a result of ruminal biohydrogenation that rapidly saturates and thus limits the availability of free unsaturated fatty acids for assimilation. The objective of this study was to evaluate the effects of glycerol on ruminal free-fatty acid (FFA) production rates and in vitro fermentation kinetics of alfalfa hay. In vitro incubations demonstrated 48% and 77% reductions in rates of FFA accumulation in incubations supplemented with 2% and 20% glycerol as compared to controls. In vitro incubations with alfalfa hay demonstrated that increasing levels of glycerol did not affect NDF digestibility of the hay. Additionally, increasing amounts of glycerol decreased the acetate to propionate ratio in the rumen. These results suggest that inhibiting bacterial fat degradation may promote ruminal passage of total lipid, thereby providing greater proportions of beneficial unsaturated fat for incorporation into beef products., (Published by Elsevier Ltd.)

Ruminal methanogenesis is considered a digestive inefficiency that results in the loss of 2-12% of the host's gross energy intake and contributes nearly 20% to the United States annual CH(4) emissions. Presently, the effects of the known CH(4) inhibitor, nitroethane, and two synthetic nitrocompounds, dimethyl-2-nitroglutarate and 2-nitro-methyl-propionate, on ruminal CH(4) production and fermentation were evaluated in vitro. After 24 h incubation at 39 degrees C under 100% CO(2), ruminal fluid cultures treated with 2.97 or 11.88 mumol ml(-1) of the respective nitrocompounds produced > 92% less CH(4) (P < 0.05) than non-treated controls. Quantification of fermentation end-products produced and H(2) balance estimates indicate that fermentation efficiencies were not compromised by the nitro-treatments., (Published by Elsevier Ltd.)

Campylobacter spp. are a leading bacterial cause of human foodborne illness. When cocultured in anaerobic Bolton broth with the hyper-ammonia producing bacterium, Clostridium aminophilum, ammonia accumulation was greater and final growth of Campylobacter jejuni was reduced (CFU>or=1.4 log10/mL) compared to that obtained by pure culture controls. Co-culture with the less active ammonia-producing saccharolytic Prevotella albensis had no effect on final C. jejuni concentrations. When co-cultured similarly except with the addition of 10 micromol/L monensin, monensin-susceptible Cl. aminophilum was reduced by 2 to 4 log10 CFU/mL and concentrations of C. jejuni, which is insensitive to monensin, did not differ from its pure culture control. These results suggest that in the absence of added monensin, the hyper ammonia-producing Cl. aminophilum may be able to outcompete asaccharolytic C. jejuni for amino acid substrates and that this competitive ability was eliminated by addition on monensin.

Experiments were conducted to determine factors that affect sensitivity of Salmonella enterica serovar Typhimurium to sodium chlorate (5mM). In our first experiment, cultures grown without chlorate grew more rapidly than those with chlorate. An extended lag before logarithmic growth was observed in anaerobic but not aerobic cultures containing chlorate. Chlorate inhibition of growth during aerobic culture began later than that observed in anaerobic cultures but persisted once inhibition was apparent. Conversely, anaerobic cultures appeared to adapt to chlorate after approximately 10h of incubation, exhibiting rapid compensatory growth. In anaerobic chlorate-containing cultures, 20% of total viable counts were resistant to chlorate by 6h and had propagated to 100% resistance (>10(9)CFU mL(-1)) by 24h. In the aerobic chlorate-containing cultures, 12.9% of colonies had detectable resistance to chlorate by 6h, but only 1% retained detectable resistance at 24h, likely because these cultures had opportunity to respire on oxygen and were thus not enriched via the selective pressure of chlorate. In another study, treatment with shikimic acid (0.34 mM), molybdate (1mM) or their combination had little effect on aerobic or anaerobic growth of Salmonella in the absence of added chlorate. As observed in our earlier study, chlorate resistance was not detected in any cultures without added chlorate. Chlorate resistant Salmonella were recovered at equivalent numbers regardless of treatment after 8h of aerobic or anaerobic culture with added chlorate; however, by 24h incubation chlorate sensitivity was completely restored to aerobic but not anaerobic cultures treated with shikimic acid or molybdate but not their combination. Results indicate that anaerobic adaptation of S. Typhimurium to sodium chlorate during pure culture is likely due to the selective propagation of low numbers of cells exhibiting spontaneous resistance to chlorate and this resistance is not reversible by molybdenum supplementation., (Published by Elsevier Ltd.)

Aims: To determine if the purported deaminase inhibitors diphenyliodonium chloride (DIC) and thymol reduce the growth and survivability of Campylobacter., Methods and Results: Growth rates of Campylobacter jejuni and Camp. coli were reduced compared to unsupplemented controls during culture in Muellar-Hinton broth supplemented with 0.25 micromol DIC or thymol ml(-1) but not with 0.01 micromol monensin ml(-1) or 1% ethanol. Recovery of Camp. jejuni and Camp. coli was reduced >5 log(10) CFU from controls after 24 h pure culture in Bolton broth supplemented with 0.25 or 1.0 micromol DIC ml(-1) or with 1.0 micromol thymol ml(-1). Similarly, each test Campylobacter strain was reduced >3 log(10) CFU from controls after 24 h mixed culture with porcine faecal microbes in Bolton broth supplemented with 0.25 or 1.0 micromol DIC ml(-1) or with 1.0 micromol thymol ml(-1). Treatments with 0.25 micromol thymol ml(-1), 0.01 micromol monensin ml(-1) or 1% ethanol were less effective. Ammonia production during culture or incubation of cell lysates was reduced by 0.25 or 1.0 micromol DIC ml(-1) but only intermittently reduced, if at all, by the other treatments., Conclusions: Diphenyliodonium chloride and thymol reduced growth, survivability and ammonia production of Camp. jejuni and Camp. coli., Significance and Impact of the Study: Results suggest a potential physiological characteristic that may be exploited to develop interventions.

Indole and 3-methylindole (skatole) are odor pollutants in livestock waste, and skatole is a major component of boar taint. Skatole causes pulmonary edema and emphysema in ruminants and causes damage to lung Clara cells in animals and humans. A gas chromatographic method that originally used a nitrogen-phosphorus detector to increase sensitivity was modified resulting in an improved flame ionization detection response for indole and skatole of 236% and 207%, respectively. The improved method eliminates the large amount of indole decomposition in the injector. A 10 micro g mL(-1) spike of indole and skatole in water and swine fecal slurries resulted in recovery of 78.5% and 96% in water and 76.1% and 85.8% in fecal slurries, respectively. The effect of the addition of nitroethane and nitroethanol at 21.8 mM in swine fecal slurries was studied on the microbial production of indole and skatole. Nitroethane and nitroethanol decreased the production of skatole in swine fecal slurries at 24 h. The nitroethane effect on l-tryptophan-supplemented fecal slurries after 6 and 24 h incubation resulted in a decrease of 69.0% (P = 0.02) and 23.5% skatole production, respectively, and a decrease of 14.9% indole at 6 h, but an increase in indole production of 81.1% at 24 h.

Ruminal methane (CH(4)) production results in the loss of up to 12% of gross energy intake and contributes nearly 20% of the United States' annual emission of this greenhouse gas. We report the effects of select nitrocompounds on ruminal fermentation after 22 h in vitro incubation (39 degrees C) with or without additions of hydrogen (H(2)), formate or both. In incubations containing no added reductant, CH(4) production was inhibited 41% by 2-nitro-1-propanol (2NPOH) and >97% by 3-nitro-1-propionic acid (3NPA), nitroethane (NE) and 2-nitroethanol (2NEOH) compared to non-treated controls and H(2) did not accumulate. With formate as the sole added reductant, nitro-treatment reduced CH(4) production by >99% and caused 42% to complete inhibition of formate catabolism compared to controls, and the accumulation of H(2) increased slightly. Nitro-treatment decreased CH(4) production 57-98% from that of controls when supplied H(2) or formate plus H(2). Formate catabolism was decreased 42-84% from that in controls by all nitro-treatments except 3NPA with both formate and H(2). Greater than 97% of the added H(2) was catabolized within controls; >84% was catabolized in nitro-treated incubations. Acetate, propionate and butyrate accumulations were unaffected by nitro-treatment irregardless of reductant; however, effects on ammonia and branched chain fatty acid accumulations varied. These results suggest that nitro-treatment inhibited formate dehydrogenase/formate hydrogen lyase and hydrogenase activity.

Campylobacter are important human foodborne pathogens known to colonize the gastrointestinal tract of cattle. The incidence of Campylobacter in cattle may be seasonal and may vary among age groups and type (beef versus dairy). Less is known about other factors that could influence the prevalence, colonization site, and shedding of Campylobacter in cattle. The objectives of this study were to evaluate the prevalence and enumerate Campylobacter at two sites along the digestive tract of beef and dairy type cattle consuming either grass or feedlot diets. In an initial study, Campylobacter was not recovered from rumen samples of any of 10 ruminally cannulated (six dairy and four beef type) pasture-reared cattle and there was no difference (p > 0.05) between cattle types on fecal Campylobacter recovery, with 50% of each type yielding culture-positive feces (overall mean +/- SE, 0.75 +/- 0.001 SEM log(10) colony-forming units [CFU]/g feces). When calculated from Campylobacter culture-positive animals only, mean fecal concentrations were 1.50 +/- 0.001 SEM log(10) CFU/g. In a follow-up study with feedlot and pasture-reared cattle (n = 18 head each), 78% of rumen and 94% of fecal samples from pastured cattle were positive for Campylobacter while 50% of the rumen and 72% of the fecal samples were positive in concentrate-fed animals. Overall mean concentration of Campylobacter was greater in feces than ruminal fluid (p < 0.05). When only Campylobacter-positive animals were analyzed, concentrations recovered from feces were higher (p < 0.05) in concentrate-fed than in pasture-fed cattle (4.29 vs. 3.34 log(10) CFU/g, respectively; SEM = 0.29). Our results suggest that the rumen environment and its microbial population are less favorable for the growth of Campylobacter and that concentrate diets may provide a more hospitable lower gastrointestinal tract for Campylobacter.

Nitroethane is a potent inhibitor of ruminal CH 4 production, a digestive inefficiency resulting in the loss of 2-15% of a ruminant's gross energy intake and an important emission source of this greenhouse gas. To assess the effect of nitroethane on methanogenesis and characterize ruminal adaptation observed with low treatment doses to this inhibitor, ruminal microbes were cultured in vitro with supplements of water (controls), 4.5 and 9 mM nitroethane, and 0.09 mM monensin, with or without 9 mM nitroethane. All treatments decreased CH 4 production >78% compared to controls; however, differential effects of treatments were observed on CO 2, butyrate isobutyrate, and valerate production. Treatments did not affect H 2 accumulation or acetate and propionate production. Most probable numbers of nitrometabolizing bacteria were increased with 4.5 and 9 mM nitroethane compared to numbers recovered from controls or monensin-containing treatments, which may explain ruminal adaptation to lower nitroethane treatments.

This study examined how different methods of applying a fibrolytic enzyme or ammonia affect the nutritive value of Bermudagrass hay and the performance of beef cattle. Fifty Angus x Brangus crossbred steers (mean initial BW 244 +/- 26 kg) were individually fed for ad libitum intake of a 5-wk regrowth of a mixture of Florakirk and Tifton 44 Bermudagrass [Cynodon dactylon (L.) Pers] hay for 84 d with a concentrate supplement (77% soybean hull pellets, 23% cottonseed meal (DM basis) fed at 1% of BW daily. The Bermudagrass was conserved as hay without treatment (control), with NH(3) (30 g/kg of DM), or with a fibrolytic enzyme (16.5 g/t, air-dry basis) that was applied immediately after cutting (Ec), at baling (Eb), or at feeding. Chromic oxide was dosed to steers for 10 consecutive days, and fecal Cr concentrations from the last 5 d were used to estimate apparent total tract digestibility. In situ ruminal DM degradability was measured by incubating ground (4-mm) hay samples in duplicate in each of 2 ruminally cannulated cows having ad libitum access to Bermudagrass hay and 500 g/d of soybean meal. Unlike the enzyme treatment, ammoniation increased (P < 0.001) the CP concentration and reduced (P < 0.001) NDF, hemicellulose, and lignin concentrations of hay. Total DMI was greater (P < 0.05) for steers fed hays treated with Ec or NH(3) than for those fed control hays. All additive treatments increased (P < 0.05) DM digestibility, and NH(3), Ec, and Eb treatments also increased (P < 0.01) NDF digestibility. The initial and final BW, ADG, BCS, G:F, and hip height of the steers were not affected (P > 0.05) by treatment. The wash loss fractions in hays treated with Ec and Eb were lower than that in the control hay, but the potentially degradable fraction, total degradable fraction, and the effective degradability were increased (P < 0.01) by NH(3) treatment. Application at cutting was the most promising method of enzyme treatment, and this treatment was almost as effective as ammonia for enhancing forage quality.