In vitro aflatoxins recovery after changing buffer or protozoa concentrations in the rumen fermentation fluid

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Abstract

This study simulates in vitro the effects of (i) rumen acidity and (ii) change in rumen protozoa numbers on the recovery of aflatoxins (AFs). Two 24-h fermentation experiments were carried out using the same batch in vitro fermentation systems and substrate (dried corn meal) containing 11.42, 2.42, 7.65 and 1.70 µg/kg of AFB1, AFB2, AFG1 and AFG2 respectively. In Experiment 1, two buffer concentrations (normal salts dosage or lowered to 25%) were tested. Buffer reduction decreased gas production (730 vs. 1101 mL, p < 0.05), volatile fatty acids (VFA) and NH3 concentrations in the fermentation liquid (39.8 vs. 46.3 mmol/L, and 31.7 vs. 46.5 mg/dL respectively, p < 0.01). Recovery of all four AFs types was higher (p < 0.01) in the reduced buffer fermentation fluid, both as a percentage of total AF incubated (73.6% vs. 62.5%, 45.9% vs. 38.1%, 33.6% vs. 17.9% and 18.9% vs. 6.24% for AFB1, AFB2, AFG1 and AFG2 respectively) and as amounts relative to VFA production (163.4 vs. 123.5, 22.1 vs. 15.7, 48.8 vs. 22.5 and 6.16 vs. 1.86 ng/100 mmol of VFA, for AFB1, AFB2, AFG1 and AFG2 respectively). In Experiment 2, Stevia rebaudiana Bertoni extracts (S) or a Camphor essential oil (Cam) were added to fermenters and compared to the control (no additives, C). S and Cam addition resulted in a 25% reduction (p < 0.05) and a 15% increase (p < 0.05) in protozoa counts respectively, when compared to C. Both plant additives slightly reduced (p < 0.05) AFB1 recovery as a percentage of total AFB1 incubated (68.5% and 67.7% vs. 74.9% for S, Cam and C respectively). Recoveries of all other AFs were unaffected by the additives. In conclusion, the rumen in vitro AFB1 recovery (63%–75%) was higher than other AFs (3%–46%) and the acidic fermentation environment increased it. In our conditions, changes in protozoa numbers did not affect AFs recovery.

Support for the size‐mediated sensitivity hypothesis within a diverse carnivore community

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Support for the size-mediated sensitivity hypothesis within a diverse carnivore community

This study provides novel empirical support to the newly introduced size-mediated sensitivity hypothesis, whereby smaller carnivores have heightened sensitivity to changing patterns of human land use and habitat management in diverse carnivore communities.


Abstract

Carnivore community dynamics are governed by a complex set of often interacting biotic, abiotic and anthropogenic factors that are increasingly volatile as a result of global change. Understanding how these changing conditions influence carnivore communities is urgent because of the important role carnivores play within ecosystems at multiple trophic levels, and the conservation threats that many carnivores face globally. While a great deal of research attention has historically been focused on large carnivores within ecosystems, the size-mediated sensitivity hypothesis has recently been proposed where the smallest carnivore in a system is likely to be the most responsive to the diverse suite of ongoing environmental and anthropogenic changes within ecological communities. We deployed camera traps at 197 sites over 4 years to monitor a diverse suite of mammalian carnivores within the Blue Ridge Mountains of western North Carolina and then used a two-step occupancy modelling–structural equation modelling framework to investigate the relative support for four primary hypothesized drivers (interspecific competition/predation, habitat complexity, food availability and anthropogenic disturbance) on carnivore occurrence. We found that each of the 10 carnivores in our system responded differently to conditions associated with each of these four hypothesized drivers, but that small and medium-sized carnivores had a greater number of significant (p < 0.05) pathways by which these conditions were influencing occupancy relative to large carnivores. In particular, the smallest carnivore observed in our study was the only species for which we found support for each of the four hypothesized drivers influencing occupancy. Collectively, our study supports the size-mediated sensitivity hypothesis and suggests that small carnivores are ideal sentinel species for global change. We echo recent calls for adopting a middle-out approach to investigations into carnivore community dynamics by refocusing sustained monitoring and research efforts on smaller carnivores within systems.

Altered expression of S100 fused‐type proteins in an atopic dermatitis skin model

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Abstract

Atopic dermatitis (AD) is a chronic inflammatory skin disorder with elevated interleukin (IL)-4 and IL-13 signatures and extensive barrier dysfunction, which is correlated with the downregulation of filaggrin (FLG). FLG is a member of the S100 fused-type protein family and this family also includes cornulin (CRNN), filaggrin-2 (FLG2), hornerin (HRNR) repetin (RPTN), trichohyalin (TCHH) and trichohyalin-like 1 (TCHHL1). The present study aimed to examine the effects of IL-4 and IL-13 and the downregulation of FLG on the expression of S100 fused-type proteins using a three-dimensional (3D) AD skin model by immunohistochemical study and quantitative polymerase chain reaction. In the 3D AD skin model, which was generated by a stimulation of recombinant IL-4 and IL-13, the expression of FLG, FLG2, HRNR and TCHH was decreased, while that of RPTN was increased in comparison to the 3D control skin. In the FLG knockdown (KD) 3D skin model, which was generated using FLG siRNA, the expression of HRNR was increased. The expression of the other proteins did not differ to a statistically significant extent. The expression of fused-S100 type protein family members may differ in AD skin. This suggests that these proteins play different roles in the pathogenesis of AD.

Menthol application on healthy and inflamed goat udders changes antimicrobial components in milk

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Abstract

Mammary glands with mastitis are usually treated with antibiotics in combination with anti-inflammatory drug application on the udder skin. Menthol is an anti-inflammatory drug. The aim of the present study was to investigate the effect of surface application of menthol on goat udders on the production of antimicrobial components in milk. Goats (5 Shiba and 11 Tokara goats) were subjected to menthol application to the udder under both healthy and inflammatory conditions. An intramammary infusion of lipopolysaccharides was carried out to induce inflammatory conditions in the udder. Milk samples were collected to determine somatic cell count (SCC) and sodium ion (Na+), antimicrobial component and cytokine concentrations. In healthy udders, menthol application increased the concentration of antimicrobial components (S100A7 and S100A8), but not in the control. In the inflamed udder, antimicrobial component (lactoferrin, S100A7, and S100A8) and inflammatory cytokine (IL-1β) concentrations were higher in the menthol group than in the control group. These results suggest that menthol application on udders augments the antimicrobial component concentration in the mammary gland under both healthy and inflammatory conditions.

Prediction of methane emissions from fattening cattle using the methane‐to‐carbon dioxide ratio

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Abstract

This study aimed to develop a prediction equation for methane (CH4) emissions from fattening cattle based on the CH4/carbon dioxide (CO2) ratio and validate the predictive ability of the developed equation. The prediction equation was developed using the CH4/CO2 ratio combined with oxygen consumption and respiratory quotient estimations that were theoretically calculated from the relation between gas emissions and energy metabolism. To validate the prediction equation, gas measurements in the headboxes were conducted using eight Japanese Black steers. The predictive ability of the developed equation was compared with that of two previously reported equations. As a result, the developed and reported equations had significant (P < 0.01) linear relationships between the observed and predicted CH4 emissions. Notably, only the developed equation had a significant (P < 0.01) linear relationship between the observed and predicted CH4 emissions when expressed per unit of dry matter intake. The results suggest that the developed prediction equation has a higher predictive ability than previously reported equations, particularly in evaluating the efficiency of CH4 emissions. Although further validation is required, the equation developed in this study can be a valuable tool for on-farm estimations of individual CH4 emissions from fattening cattle.

Genome‐wide detection of changes in allelic frequency in Landrace pigs selected for resistance to mycoplasma pneumonia of swine

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Abstract

Closed-pig line breeding could change the genetic structure at a genome-wide scale because of the selection in a pig breeding population. We investigated the changes in population structure among generations at a genome-wide scale and the selected loci across the genome by comparing the observed and expected allele frequency changes in mycoplasma pneumonia of swine (MPS)-selected pigs. Eight hundred and seventy-four Landrace pigs, selected for MPS resistance without reducing average daily gain over five generations, had 37,299 single nucleotide polymorphisms (SNPs) and were used for genomic analyses. Regarding population structure, individuals in the first generation were the most widely distributed and then converged into a specific group, as they were selected over five generations. For allele frequency changes, 96 and 14 SNPs had higher allele frequency changes than the 99.9% and 99.99% thresholds of the expected changes, respectively. These SNPs were evenly spread across the genome, and a few of these selected regions overlapped with previously detected quantitative trait loci for MPS and immune-related traits. Our results indicated that the considerable changes in allele frequency were identified in many regions across the genome by closed-pig line breeding based on estimated breeding value.

Use of a commercial indoor positioning system for monitoring resting time and moving distance in group‐housed dairy calves

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Abstract

To assess the usefulness of a commercially available indoor positioning system for monitoring the resting time and moving distance in group-housed dairy calves as indicators of their health status, five dairy calves were housed in a free barn, and their coordinate was recorded. The mean displacement (cm/s) within a minute showed a double-mixture distribution. Actual observations revealed that the minutes in the first distribution with shorter displacement were mostly the time that the calves spent lying. To predict the daily lying time and moving distance, a mixed distribution was divided at a threshold value. The mean sensitivity (the proportion of total minutes predicted correctly as lying, in total minutes observed lying) was more than 92%. The daily fluctuation in lying time correlated well with the actual lying time (r = 0.758, p < 0.01). The range of fluctuations was 740–1308 min/day and 724–1269 m/day for daily lying time and moving distance, respectively. The rectal temperature was correlated with daily lying time (r = 0.441, p < 0.001) and distance moved (r = 0.483, p < 0.001). The indoor positioning system can be a useful tool for early illness detection in calves before the onset of symptoms in group-housing systems.

Rumen microbial composition associated with the non‐glucogenic to glucogenic short‐chain fatty acids ratio in Holstein cows

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Abstract

This study aimed to determine the physiological features and rumen microbial composition associated with the non-glucogenic-to-glucogenic short-chain fatty acids ratio (NGR). Holstein cows were housed in a free-stall barn with an automatic milking system and fed a partially mixed ration. Physiological and microbial analyses were performed on 66 datasets collected from 66 cows (50–250 days in milk). NGR was positively correlated with ruminal pH, relative abundances of protozoa and fungi, methane conversion factor, methane intensity, plasma lipids, parity, and milk fat, and negatively correlated with total short-chain fatty acids. To highlight the differences in bacterial and archaeal compositions between NGRs, low-NGR cows (N = 22) were compared with medium-NGR (N = 22) and high-NGR (N = 22) cows. The low-NGR group was characterized by a lower abundance of Methanobrevibacter and a higher abundance of operational taxonomic units belonging to the lactate-producing, such as Intestinibaculum, Kandleria, and Dialister, and the succinate-producing Prevotella. Our findings indicate that NGR affects the methane conversion factor, methane intensity, and blood and milk compositions. Low NGR is associated with a higher abundance of lactate- and succinate-producing bacteria and lower abundances of protozoa, fungi, and Methanobrevibacter.

Comparison of carcass traits and nutritional profile in two different broiler‐type duck lines

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Abstract

Cherry Valley ducks (CVDs) and White Kaiya ducks (WKDs) are judged to be fast- and slow-growing lines, respectively. To investigate the carcass traits and nutritional profile at their marketable ages, 12 birds (38 days for CVDs, n = 6; 56 days for WKDs, n = 6) were randomly selected and slaughtered. Indicators such as breast muscle weight, shear force, and proximate composition were comprehensively detected. Although the carcass and breast muscle weight in WKDs were significantly lower, remarkably higher intramuscular fat and tenderness and less moisture content were observed in WKDs. Besides, WKDs contained higher contents of Cu, Zn, and Ca, whereas CVDs contained higher leucine (Leu) and histidine (His) compositions (P < 0.01). Moreover, higher monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) along with lower saturated fatty acids (SFAs) were detected in WKDs (P < 0.01). Taken together, despite light carcass and breast muscle weight, WKDs had advantages in nutritional compositions except for amino acid constituents, including intramuscular fat, MUFAs, and PUFAs, as well as Cu, Zn, and Ca. These data would not only provide genetic resources for breeding new duck lines but also offer a useful reference for making decisions on high-nutrient meat consumption.

L‐histidine inhibits the heat‐induced gelation of actomyosin in a low ionic strength solution

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Abstract

The heat-induced gelation of actomyosin plays a key role in meat processing. Our previous study showed that L-histidine could affect the characteristics of a heat-induced gel of myosin on a low ionic strength. To apply the specific effect of L-histidine to meat processing, the heat-induced gel properties of actomyosin in the presence of L-histidine were investigated. Actomyosin in a low ionic strength solution containing L-histidine did not form a gel upon heating. The dynamic rheological properties of actomyosin in low ionic strength solutions were distinct depending on the presence or absence of L-histidine. Electron microscopy showed that, heated at 50°C, actomyosin in a low ionic strength solution containing L-histidine remained a filamentous structure. The surface hydrophobicity of actomyosin was stable up to 50°C in a low ionic strength solution containing L-histidine. In conclusion, L-histidine might suppress the aggregation of actomyosin and inhibit heat-induced gelation in a low ionic strength solution.