A sampling strategy for the determination of infrared temperature of relevant external body surfaces of dairy cows.

Infrared thermography is a tool to investigate the welfare of cattle. This study aimed to identify a sampling strategy for recording infrared thermograms in dairy cows, in order to most efficiently determine biologically relevant changes in the maximum infrared temperature (IRT) of the eyes and coronary band of forelimbs. Thirty-one dairy cows were used for the study. They were assessed with four replicates of thermograms for each of the head and lower forelimb per cow for 6 mostly consecutive days (sessions). The data obtained were subjected to random effects Analysis of Variance which was used to estimate the variance components for this sampling model, using maximum IRT of both eyes; (left + right eye)/2 and both limbs; (left + right coronary band of forelimb)/2 as dependant variables. The variance components were used to calculate least significant differences (LSD) between two theoretical treatment groups under different sampling scenarios. Analysis showed that there was minimal improvement in precision beyond 2 thermograms within a session but there was improvement with increasing the number of sessions from 2 to 3. The LSD of both eyes and both limbs reached a biologically relevant difference (0.4 and 0.9 °C, respectively) at a minimum number of 14 - 16 cows monitored for 2 consecutive thermography sessions, or 10 - 12 cows for 3 sessions. We conclude that no more than 2 replicate IRT measures are required per session but that measuring on 3 consecutive days should be considered, depending on whether time or number of cows used is the primary limitation.

Food Starch Structure Impacts Gut Microbiome Composition.

Starch is a major source of energy in the human diet and is consumed in diverse forms. Resistant starch (RS) escapes small intestinal digestion and is fermented in the colon by the resident microbiota, with beneficial impacts on colonic function and host health, but the impacts of the micro- and nanoscale structure of different physical forms of food starch on the broader microbial community have not been described previously. Here, we use a porcine in vitro fermentation model to establish that starch structure dramatically impacts microbiome composition, including the key amylolytic species, and markedly alters both digestion kinetics and fermentation outcomes. We show that three characteristic food forms of starch that survive digestion in the small intestine each give rise to substantial and distinct changes in the microbiome and in fermentation products. Our results highlight the complexity of starch fermentation processes and indicate that not all forms of RS in foods are degraded or fermented in the same way. This work points the way for the design of RS with tailored degradation by defined microbial communities, informed by an understanding of how substrate structure influences the gut microbiome, to improve nutritive value and/or health benefits.IMPORTANCE Dietary starch is a major component in the human diet. A proportion of the starch in our diet escapes digestion in the small intestine and is fermented in the colon. In this study, we use a model of the colon, seeded with porcine feces, in which we investigate the fermentation of a variety of starches with structures typical of those found in foods. We show that the microbial community changes over time in our model colon are highly dependent on the structure of the substrate and how accessible the starch is to colonic microbes. These findings have important implications for how we classify starches reaching the colon and for the design of foods with improved nutritional properties.

Karrikins Identified in Biochars Indicate Post-Fire Chemical Cues Can Influence Community Diversity and Plant Development.

BACKGROUND: Karrikins are smoke-derived compounds that provide strong chemical cues to stimulate seed germination and seedling growth. The recent discovery in Arabidopsis that the karrikin perception system may be present throughout angiosperms implies a fundamental plant function. Here, we identify the most potent karrikin, karrikinolide (KAR1), in biochars and determine its role in species unique plant responses. METHODS: Biochars were prepared by three distinct commercial-scale pyrolysis technologies using systematically selected source material and their chemical properties, including karrikinolide, were quantified. Dose-response assays determined the effects of biochar on seed germination for two model species that require karrikinolide to break dormancy (Solanum orbiculatum, Brassica tourneforttii) and on seedling growth using two species that display plasticity to karrikins, biochar and phytotoxins (Lactuca sativa, Lycopersicon esculentum). Multivariate analysis examined relationships between biochar properties and the plant phenotype. FINDINGS AND CONCLUSIONS: Results showed that karrikin abundant biochars stimulated dormant seed germination and seedling growth via mechanisms analogous to post-fire chemical cues. The individual species response was associated with its sensitivity to karrikinolide and inhibitory compounds within the biochars. These findings are critical for understanding why biochar influences community composition and plant physiology uniquely for different species and reaffirms that future pyrolysis technologies promise by-products that concomitantly sequester carbon and enhance plant growth for ecological and broader plant related applications.

Soluble arabinoxylan enhances large intestinal microbial health biomarkers in pigs fed a red meat-containing diet.

OBJECTIVES: The aim of this study was to investigate how moderately increased dietary red meat combined with a soluble fiber (wheat arabinoxylan [AX]) alters the large intestinal microbiota in terms of fermentative end products and microbial community profiles in pigs. METHODS: Four groups of 10 pigs were fed Western-type diets containing two amounts of red meat, with or without a solubilized wheat AX-rich fraction for 4 wk. After euthanasia, fermentative end products (short-chain fatty acids, ammonia) of digesta from four sections of large intestine were measured. Di-amino-pimelic acid was a measure of total microbial biomass, and bacterial profiles were determined using a phylogenetic microarray. A factorial model determined effects of AX and meat content. RESULTS: Arabinoxylan was highly fermentable in the cecum, as indicated by increased concentrations of short-chain fatty acids (particularly propionate). Protein fermentation end products were decreased, as indicated by the reduced ammonia and branched-chain ratio although this effect was less prominent distally. Microbial profiles in the distal large intestine differed in the presence of AX (including promotion of Faecalibacterium prausnitzii), consistent with an increase in carbohydrate versus protein fermentation. Increased di-amino-pimelic acid (P < 0.0001) suggested increased microbial biomass for animals fed AX. CONCLUSIONS: Solubilized wheat AX has the potential to counteract the effects of dietary red meat by reducing protein fermentation and its resultant toxic end products such as ammonia, as well as leading to a positive shift in fermentation end products and microbial profiles in the large intestine.

Soluble arabinoxylan alters digesta flow and protein digestion of red meat-containing diets in pigs.

OBJECTIVES: The aim of this study was to investigate how a moderate increase in dietary meat content combined (or not) with soluble fibre would influence protein digestion as well as digesta characteristics and flow. METHODS: Four groups of pigs were fed Western-style diets (high-protein/high-fat) containing two types of barbecued red meat, one with and one without a wheat arabinoxylan-rich fraction. After 4 wk, digesta samples were collected from small and large intestinal sites and analyzed for protein, amino acids, dry matter, and acid-insoluble ash. Tissue samples were also collected from each site. RESULTS: Arabinoxylan consumption led to somewhat lower apparent protein digestibility within the small and large intestines as well as shorter mean retention times. This suggests that the lowered protein digestibility is due, at least partly, to shorter access time to digestive proteases and absorptive surfaces. Additionally, digesta mass was higher in pigs fed arabinoxylan while dry matter (%) was lower, indicating an increased digesta water-holding capacity due to the presence of a soluble dietary fiber. CONCLUSION: Data showed that solubilized wheat arabinoxylan provides potential health benefits through decreased protein digestibility, increased digesta mass, and reduced mean retention time, even for diets with a moderately higher protein content. These factors are associated with efficiency of digestion and satiety, both of which have implications for prevention of obesity and other health disorders.

The effect of group size on vigilance in a semi-solitary, fossorial marsupial (Lasiorhinus latifrons).

Prey species that congregate gain protection against predatory attacks and this advantage is often reflected by a reduction in vigilance behaviour by individuals in larger groups. Comparatively few studies have investigated vigilance in solitary animals, but those that have, found that vigilance increases as group size increases because of the threat posed by conspecifics and/or competition for resources. The southern hairy-nosed wombat (Lasiorhinus latifrons) is a large fossorial, nocturnal marsupial that is neither strictly solitary nor gregarious, sharing warren systems with multiple conspecifics. We investigated the effects of conspecific presence on vigilance behaviour in this semi-solitary species. We observed wild-born, adult L. latifrons wombats in three group sizes (Large (1♂, 3♀), Medium (1♂, 2♀) and Small (1♂, 1♀)) in a captive, naturalistic environment that allowed above-ground and den behaviour monitoring. Vigilance behaviours were performed less frequently by wombats in large groups (e.g. scanning, counts/day, Large: 55, Medium: 69, Small: 115, P=0.002) and more frequently as the distance from their nearest conspecific increased (r64=0.30, P= 0.016). Vigilance within burrows was also affected by social influences, with solitary wombats significantly more vigilant than those denning with a conspecific (e.g. scanning: conspecific absent: 0.13/5min, present: 0.03/5min, P<0.0001). It is concluded that the presence of conspecifics reduces vigilance in L. latifrons wombats, even within burrows, and this may partially explain the occurrence of warren sharing in the wild.

Eliminative behavior of captive numbats, Myrmecobius fasciatus (Mammalia; Marsupialia): pattern and identification of fecal deposits.

This study examined the spatial defecation patterns of numbats within captivity and tested the efficacy of a food colorant as a fecal marker in this species. Rather than randomly distributing scats throughout their environment, the numbats aggregated their feces at specific sites forming latrines. It is unclear whether the strong inclination for latrine formation was due to this species' inherent behavior or is a direct result of captivity. Males were found to have a higher daily defecation rate, different defecation time, larger number of latrines, and greater number of scats per quadrant, as compared to females. In this study, the majority of scats were deposited along enclosure boundaries and for both sexes there was a higher probability of latrines being placed along enclosure fencing shared with a female neighbor. The high concentration of latrines along boundaries suggests that they may play a role in territorial defense. The results also indicated that captive numbats tend to choose defecation points away from food and refuge sites. Transit and total retention time of the marker through the GIT was ≤3 hr and between 24 and 27 hr, respectively. A marker dose of 3 gtts feed(-1) × 2 feeds day(-1) was required to reach a steady and detectable state of marker output, which enabled accurate identification of individual samples during the breeding season. Reliable labeling was obtained using blue and red colored food dye, and there was no evidence that incorporation of the marker into the diet had any negative effects on food intake.

Non-invasive assessment of stress in captive numbats, Myrmecobius fasciatus (Mammalia: Marsupialia), using faecal cortisol measurement.

Annual patterns of faecal cortisol metabolite (FCM) secretion were examined in six captive numbats (Myrmecobius fasciatus). The use of enzyme-immunoassay for the measurement of FCM in the numbat faeces was validated using an adrenocorticotropic hormone (ACTH) challenge and the resultant FCM measurements represent the first description of adrenal endocrinology in this species. Total overall, baseline and peak FCM mean concentrations varied according to individual, but not gender. For males, mean baseline and overall FCM secretion was higher in spring in summer (compared to winter and autumn) and was elevated during the breeding season. For females, mean baseline FCM secretion did not differ by season or breeding season, but mean overall FCM secretion was elevated during the breeding season. Thus, male (but not female) numbats display an annual change in FCM secretion that is strongly linked to their seasonal pattern of reproduction. Significant FCM elevations (n=178) were observed in response to 20 different stressors, with these stressors being allocated to one of six categories: ANIM, ENVIRO, HAND, HEALTH, MAN and UNK. The mean proportion of positive responses to each category varied according to category, season and breeding season, but did not vary by individual or gender. ANIM and HEALTH stressors elicited a higher response rate than all other categories and an increase in the number of ANIM, ENVIRO, and HEALTH stressors were observed during the breeding season. Although there were multiple stressors within the captive environment that the numbats reacted to, this did not translate into a welfare issue.

Control of the koala (Phascolarctos cinereus) anterior pituitary-gonadal axis with analogues of GnRH.

The aim of the present study was to determine whether analogues of gonadotrophin-releasing hormone (GnRH) could be used to both induce an acute testosterone response and suppress anterior pituitary function in male koalas, and induce a luteal phase in female koalas. Experiment 1 characterised the steroidogenic response of male koalas to administration of 30 microg (4.3 microg kg(-1)) natural-sequence GnRH. Intra-muscular injection of natural-sequence GnRH induced the release of LH and testosterone with peak concentrations at 30 min (3.7 +/- 1.9 ng mL(-1)) and 2 h (5.4 +/- 0.5 ng mL(-1)), respectively. In Experiment 2, a single injection of the GnRH antagonist acyline (100 microg (14.3 microg kg(-1)) or 500 microg (71.4 microg kg(-1))) did not influence the testosterone response to subsequent injections of natural-sequence GnRH. In Experiment 3, 4 microg (~0.67 microg kg(-1)) of the GnRH agonist buserelin induced a luteal phase in five female koalas based on a LH surge, secretion of progestogen, and a normal-length oestrous cycle. The findings have shown that (1) natural-sequence GnRH can be used to test gonadotroph cell function and determine the testosterone-secreting capacity of male koalas, (2) the GnRH antagonist, acyline, at the dose rates used, does not suppress the pituitary-testis axis in male koalas, and (3) the GnRH agonist, buserelin, induces a normal luteal phase in female koalas.

Successful artificial insemination in the koala (Phascolarctos cinereus) using extended and extended-chilled semen collected by electroejaculation.

Artificial insemination in the koala using chilled, electroejaculated semen provides for a marked improvement in the reproductive and genetic management of captive koala colonies in Australia and internationally, and makes available the option of using semen collected from wild populations to expand restricted gene pools. Dilution of koala semen for artificial insemination is complicated because koalas are induced ovulators, and it is thought that ovulating factors are present in the semen, so that semen extension for preservation purposes might be anticipated to result in a failure to induce ovulation. The first two experiments of this study were designed to determine whether artificial insemination using undiluted, extended, and extended-chilled semen collected by electroejaculation was capable of inducing a luteal phase and/or the production of pouch young. In Experiment 1, 1 ml undiluted electroejaculated semen, 2 ml diluted (1:1) semen, and 1 ml diluted (1:1) semen resulted in seven of nine, six of nine, and six of nine koalas showing a luteal phase, respectively; four pouch young were produced in each treatment. A second artificial insemination experiment was conducted in which 2 ml diluted (1:1) semen was administered in three groups of nine koalas. The first group received semen that had been collected and diluted immediately without chilling, the second group was deposited with semen stored chilled for 24 h, and the final group received semen that had been chilled for 72 h. In the first group, five females had a luteal phase, but none became pregnant. In group 2, two of the five females that had a luteal phase gave birth, whereas in group 3, four of the six females that had a luteal phase produced pouch young. In addition, experiment 3 was conducted to determine whether it was possible to produce pouch young by naturally mating koalas that were in the latter stages of their behavioral estrus; this information is important to the logistics of transporting koala semen for artificial insemination by establishing the maximum time frame in which females might be expected to shed a fertile oocyte. Of the 12 females mated on Day 8 of estrus, 6 gave birth, whereas only 3 of the 10 females naturally mated on Day 10 of estrus produced pouch young. The majority of females (21 of 22) in experiment 3 showed evidence of a luteal phase. Together, these experiments have shown that it is possible to use undiluted, extended, or extended-chilled semen to produce koala offspring up to Day 8 of estrus at conception rates similar to those achieved following natural mating. These findings represent a significant advancement in the use of reproductive technology in marsupials and provide the basis for the shipment of koala semen over long distances. The pouch young produced in this study represent the first marsupials born following artificial insemination of extended-chilled semen and bring the total number of koalas produced by artificial insemination to 31.

Use of a GnRH agonist and hCG to obtain an index of testosterone secretory capacity in the koala (Phascolarctos cinereus).

Testosterone secretion in mammals typically occurs in random pulses such that a single blood sample provides limited information on reproductive endocrine status. However, it has been shown in several species that an index of the prevailing testosterone biosynthetic capacity of the testes can be obtained by measuring the increase in circulating testosterone after injection of a GnRH agonist or human chorionic gonadotrophin (hCG). Hence, the aims of the present study were to examine fluctuations in testosterone secretion in the koala (n = 6) over a 24-hour period and then characterise testosterone secretion after injection of the GnRH agonist buserelin (4 micro g) or hCG (1000 IU). The latter was used to establish an index of the prevailing testosterone biosynthetic capacity of the koala testis. Individual koalas showed major changes in blood testosterone concentrations over 24 hours, but there was no apparent diurnal pattern of testosterone secretion (P > .05). Injection of buserelin and hCG resulted in an increase (P < .05) in blood testosterone concentration. After injection of exogenous hormone, near maximal concentrations of testosterone occurred at around 60 minutes. There was a tendency for plasma testosterone to decline after 90 minutes with buserelin, but concentrations remained close to the upper limit for 240 minutes with hCG. There were strong positive correlations between the average testosterone concentration over 24 hours and the maximum observed testosterone concentration after stimulation with GnRH and hCG (GnRH, r = .772; P = .07 and hCG, r = 1.0; P < .01). The findings in the present study confirmed that individual male koalas can show large fluctuations in blood testosterone concentrations over time and that a GnRH agonist and hCG can be used in the koala to obtain an index of the prevailing steroidogenic capacity of the testes.