Weight Gain, Glucose Tolerance, and the Gut Microbiome of Male C57BL/6J Mice Housed on Corncob or Paper Bedding and Fed Normal or High-Fat Diet.

Understanding how differences in animal husbandry practices affect the reproducibility of research results is critical. We sought to understand how different beddings might influence dietary obesity studies. We compared the effects of paper and corncob bedding on weight gain, metabolism, and gut microbiome (GM) of mice fed a high-fat diet (HFD) or a normal diet (ND) and evaluated effects on fecal and cecal microbiomes collected from these cohorts after euthanasia. Male C57BL/6J mice at 5 wk age were allowed to acclimate to the facility and the assigned bedding for one week before being placed on HFD or remaining on the ND for 12 wk. Fecal pellets and cecal samples were collected and frozen for batched 16S sequencing. Mice had similar body weight, visceral gonadal white adipose tissue (GWAT), subcutaneous inguinal white adipose tissue (IWAT), liver and spleen weights and metabolic changes regardless of the bedding type. Baseline microbiota differences were detected one week after bedding assignment. After 12 wk, the GM showed significant differences depending on both bedding and diet. The effects of the bedding were not significantly different between endpoint fecal and cecal GM, despite the inherent differences in microbiota in fecal and cecal samples. A correlation was detected between diet and the relative abundance of Bacteroidetes and Verrucomicrobia: Akkermansia. In conclusion, this study demonstrates the importance of considering bedding type when performing dietary experiments.

Automated Monitoring of Panting for Feedlot Cattle: Sensor System Accuracy and Individual Variability.

Heat stress causes significant economic losses by reducing the productivity and welfare of cattle whilst requiring a significant investment in resource for amelioration. Panting score (PS) is considered a robust indicator of cattle heat stress; however, individualised visual monitoring is impractical. Thermal index-based monitoring and mitigation decisions are applied at the herd level, but they have limited application for the individual animal. As such, an automated system to monitor the real-time animal response to heat stress is required for strategic mitigation. Our objectives were to validate an accelerometer-based ear tag sensor to monitor cattle panting and to determine individual variability in heat stress responses with reference to thermal indices. Two experiments were conducted: Experiment 1 validated the sensors, and Experiment 2 determined individual variability comparing sensor data against thermal indices. Ear tag sensors were fitted at feedlot entry to continuously monitor the behaviour of 100 steers of mixed breed in Experiment 1 and 200 steers and heifers of mixed breed in Experiment 2. Sensor-derived 'heavy breathing' was validated against visually observed PS. Sensor-derived behaviour bouts were analysed as 'raw', and single behaviour states were also converted to the preceding bout of ≥2 min, which was referred to as 'fill' data for the validation study. Our results demonstrate the sensors' ability to accurately monitor panting in feedlot cattle. Sensor-recorded 'heavy breathing' duration per animal was highly correlated to observed panting duration for both raw (r = 0.89) and fill (r = 0.90) data; however, the concordance correlation co-efficient was lower for raw (0.45) as compared with fill (0.76). Predicted agreement for raw data were 75%, 45%, and 68% and predicted agreement for fill data were 65%, 54%, and 83% for PS0, PS1, and PS2, respectively. Sensitivity for raw data were 39%, 37%, and 45% and for fill data, they were 59%, 54% and 82% for all PS data, PS1 and PS2, respectively. Specificity and positive predictive values for both raw (77% and 79%, respectively) and fill (65% and 77%, respectively) data show the probability of reporting false positives by sensors to be low. Experiment 2 revealed that the duration of panting increased from 0800 to 1700 h alongside changes in thermal indices with significant differences between and within breed and coat colour categories of cattle, suggesting that grouping and allocating heat amelioration measures by breed and coat colour can be effective in commercial feedlots. However, there was high variability (CV > 80%) in the duration of panting between individuals within the same breed and same coat colour, revealing the potential for strategic management at an individual level, and with the same data, genetic selection for heat resilience.

The intake pattern and feed preference of layer hens selected for high or low feed conversion ratio.

Feed accounts for the greatest proportion of egg production costs and there is substantial variation in feed to egg conversion ratio (FCR) efficiency between individual hens. Despite this understanding, there is a paucity of information regarding layer hen feeding behaviour, diet selection and its impact on feed efficiency. It was hypothesised that variation in feed to egg conversion efficiency between hens may be influenced by feeding behaviour. For this experiment, two 35-bird groups of ISA Brown layers were selected from 450 individually caged hens at 25-30 weeks of age for either low FCR < 1.8 ± 0.02 (high feed efficiency (HFE) or high FCR > 2.1 ± 0.02 (low feed efficiency (LFE)). For each of these 70 hens, intake of an ad-libitum mash diet at 2-minute time intervals, 24 h a day, for 7 days was determined alongside behavioural assessment and estimation of the selection of components of the mash. The group selected for HFE had a lower feed intake, similar egg mass and associated lower FCR when compared with the LFE group. Whilst feed intake patterns were similar between HFE and LFE hens, there was a distinct intake pattern for all layer hens with intake rate increasing from 0300 to 1700 h with a sharp decline to 2200 h. High feed efficiency hens selected a diet with 25% more ash and 4% less gross energy than LFE hens. The LFE hens also spent more time eating with more walking events, but less time spent resting, drinking, preening and cage pecking events as compared with HFE hens. In summary, there was no contrasting diurnal pattern of feed consumption behaviour between the groups ranked on feed efficiency, however high feed efficiency hens consumed less feed and selected a diet with greater ash content and lower gross energy as compared with LFE hens. Our work is now focused on individual hen diet selection from mash diets with an aim of formulating precision, targeted diets for greater feed efficiency.

Both genome segments contribute to the pathogenicity of very virulent infectious bursal disease virus.

Infectious bursal disease virus (IBDV) causes an economically significant disease of chickens worldwide. Very virulent IBDV (vvIBDV) strains have emerged and induce as much as 60% mortality. The molecular basis for vvIBDV pathogenicity is not understood, and the relative contributions of the two genome segments, A and B, to this phenomenon are not known. Isolate 94432 has been shown previously to be genetically related to vvIBDVs but exhibits atypical antigenicity and does not cause mortality. Here the full-length genome of 94432 was determined, and a reverse genetics system was established. The molecular clone was rescued and exhibited the same antigenicity and reduced pathogenicity as isolate 94432. Genetically modified viruses derived from 94432, whose vvIBDV consensus nucleotide sequence was restored in segment A and/or B, were produced, and their pathogenicity was assessed in specific-pathogen-free chickens. We found that a valine (position 321) that modifies the most exposed part of the capsid protein VP2 critically modified the antigenicity and partially reduced the pathogenicity of 94432. However, a threonine (position 276) located in the finger domain of the virus polymerase (VP1) contributed even more significantly to attenuation. This threonine is partially exposed in a hydrophobic groove on the VP1 surface, suggesting possible interactions between VP1 and another, as yet unidentified molecule at this amino acid position. The restored vvIBDV-like pathogenicity was associated with increased replication and lesions in the thymus and spleen. These results demonstrate that both genome segments influence vvIBDV pathogenicity and may provide new targets for the attenuation of vvIBDVs.

Interactions of Tc(IV) with humic substances.

To understand the key processes affecting 99Tc mobility in the subsurface and help with the remediation of contaminated sites, the binding constants of several humic substances (humic and fulvic acids) with Tc(IV) were determined, using a solvent extraction technique. The novelty of this paper lies in the determination of the binding constants of the complexes formed with the individual species TcO(OH)+ and TcO(OH)2(0). Binding constants were found to be 6.8 and between 3.9 and 4.3, for logß1,-1,1 and logß1,-2,1, respectively; these values were little modified by a change of ionic strength, in most cases, between 0.1 and 1.0 M, nor were they by the nature and origin of the humic substances. Modeling calculations based on these show TcO(OH)-HA to be the predominant complex in a system containing 20 ppm HA and in the 4-6 pH range, whereas TcO(OH)2(0) and TcO(OH)2-HA are the major species, in the pH 6-8 range.

Characterization of vaginal microbial communities in adult healthy women using cultivation-independent methods.

The normal microbial flora of the vagina plays an important role in preventing genital and urinary tract infections in women. Thus an accurate understanding of the composition and ecology of the ecosystem is important to understanding the aetiology of these diseases. Common wisdom is that lactobacilli dominate the normal vaginal microflora of post-pubertal women. However, this conclusion is based on methods that require cultivation of microbial populations; an approach that is known to yield a biased and incomplete assessment of microbial community structure. In this study cultivation-independent methods were used to analyse samples collected from the mid-vagina of five normal healthy Caucasian women between the ages of 28 and 44. Total microbial community DNA was isolated following resuspension of microbial cells from vaginal swabs. To identify the constituent numerically dominant populations in each community 16S rRNA gene libraries were prepared following PCR amplification using the 8f and 926r primers. From each library, the DNA sequences of approximately 200 16S rRNA clones were determined and subjected to phylogenetic analyses. The diversity and kinds of organisms that comprise the vaginal microbial community varied among women. Species of Lactobacillus appeared to dominate the communities in four of the five women. However, the community of one woman was dominated by Atopobium sp., whereas a second woman had appreciable numbers of Megasphaera sp., Atopobium sp. and Leptotrichia sp., none of which have previously been shown to be common members of the vaginal ecosystem. Of the women whose communities were dominated by lactobacilli, there were two distinct clusters, each of which consisted of a single species. One class consisted of two women with genetically divergent clones that were related to Lactobacillus crispatus, whereas the second group of two women had clones of Lactobacillus iners that were highly related to a single phylotype. These surprising results suggest that culture-independent methods can provide new insights into the diversity of bacterial species found in the human vagina, and this information could prove to be pivotal in understanding risk factors for various infectious diseases.