Population variability in animal health: Influence on dose–exposure–response relationships: Part I: Drug metabolism and transporter systems

There is an increasing effort to understand the many sources of population variability that can influence drug absorption, metabolism, disposition, and clearance in veterinary species. This growing interest reflects the recognition that this diversity can influence dose–exposure–response relationships and can affect the drug residues present in the edible tissues of food‐producing animals. To appreciate the pharmacokinetic diversity that may exist across a population of potential drug product recipients, both endogenous and exogenous variables need to be considered. The American Academy of Veterinary Pharmacology and Therapeutics hosted a 1‐day session during the 2017 Biennial meeting to explore the sources of population variability recognized to impact veterinary medicine. The following review highlights the information shared during that session. In Part I of this workshop report, we consider sources of population variability associated with drug metabolism and membrane transport. Part II of this report highlights the use of modeling and simulation to support an appreciation of the variability in dose–exposure–response relationships.     

2‐Hydroxy‐4‐methylthio butanoic acid and DL‐methionine for Japanese quails in production

An experiment was performed using 1,000 laying Japanese quails to assess the availability of two alternative dietary methionine sources. Treatment 01 = Basal Feed that is deficient in digestible methionine + cystine (Met + Cys). The other treatments were constituted by Met + Cys levels of 0.8, 1.60 and 2.40 g/kg, supplemented with DL‐Methionine‐99%, HMTBA‐88% and HMTBA‐84%, being 10 treatments in total. The following characteristics were studied: feed intake (g/bird/day), egg production (egg/day × 100), egg weight (g/egg), egg mass (g/egg), feed conversion per egg dozen (kg feed/dozen eggs), feed conversion per egg mass (kg feed/kg eggs), relative yolk weight (g/100 g of egg), relative albumen weight (g/100 g of egg), relative shell weight (g/100 g of egg), shell thickness (mm) and specific gravity (g/cm³). In general result comment, supplemental methionine sources must be included in the poultry diet. The different methionine sources affect the performance of quails, and the increase in the levels within each source improves the performance variables. Significant effect was observable on performance variables and egg quality variables, being that DLM‐99% is superior to the other sources. The HMTBA‐88% source is superior to the HMTBA‐84% source for the same aforementioned variables. In conclusion, the bioefficacy values of the HMTBA‐88% and HMTBA‐84% sources compared to the DLM‐99% source on an equimolar basis were 81 and 79%, respectively, for the performance variables, and 83 and 74 while the methionine sources were equivalent for the variables related to egg quality.     

Patient characteristics influencing the variability of distributed parameter‐based models in DCE‐CT kinetic analysis

Kinetic parameter variability may be sensitive to kinetic model choice, kinetic model implementation or patient‐specific effects. The purpose of this study was to assess their impact on the variability of dynamic contrast‐enhanced computed tomography (DCE‐CT) kinetic parameters. A total of 11 canine patients with sinonasal tumours received high signal‐to‐noise ratio, test‐double retest DCE‐CT scans. The variability for three distributed parameter (DP)‐based models was assessed by analysis of variance. Mixed‐effects modelling evaluated patient‐specific effects. Inter‐model variability (CV_inter) was comparable to or lower than intra‐model variability (CV_intra) for blood flow (CV_inter:[4–28%], CV_intra:[28–31%]), fractional vascular volume (CV_inter:[3–17%], CV_intra:[16–19%]) and permeability‐surface area product (CV_inter:[5–12%], CV_intra:[14–15%]). The kinetic models were significantly (P<0.05) impacted by patient characteristics for patient size, area underneath the curve of the artery and of the tumour. In conclusion, DP‐based models demonstrated good agreement with similar differences between models and scans. However, high variability in the kinetic parameters and their sensitivity to patient size may limit certain quantitative applications.     

Handsewn Semiclosed Single‐Layer Jejunocecal Side‐To‐Side Anastomosis in the Horse

Objective: To report a technique for semiclosed 1‐layer side‐to‐side jejunocecal anastomosis in horses. Study Design: Experimental study and clinical reports. Sample Population: Part 1—In vitro: Intestinal specimens from 24 horses collected immediately after death at an abattoir. Part 2—Clinical cases: 10 horses with clinical signs of colic requiring jejunocecostomy. Methods: Mean time to perform twelve 2‐layer handsewn (HS2L) and 12 semiclosed 1‐layer modified handsewn (SC) jejunocecal anastomoses was compared. Mean bursting pressures of anastomoses measured with a modified tank inflation test were compared. The SC technique was used in 10 horses that required jejunocecal anastomosis with and without resection (complete or incomplete ileocecal bypass). Results: The SC technique was significantly quicker to perform than HS2L technique. Clinically, the technique appeared safe with a major complication, associated with obstruction from kinking of the anastomosis, occurring in 1 horse. Conclusions: The SC technique was easy to perform with very little mucosal exposure in comparison to the HS2L technique, and was safe and effective in restoring intestinal continuity in clinical cases. Clinical Relevance: The SC technique should be considered for jejunocecostomy in horses because it reduces anastomosis time and mucosal exposure compared with other techniques.     

Mathematical modeling and simulation in animal health. Part III: Using nonlinear mixed‐effects to characterize and quantify variability in drug pharmacokinetics

A common feature of human and veterinary pharmacokinetics is the importance of identifying and quantifying the key determinants of between‐patient variability in drug disposition and effects. Some of these attributes are already well known to the field of human pharmacology such as bodyweight, age, or sex, while others are more specific to veterinary medicine, such as species, breed, and social behavior. Identification of these attributes has the potential to allow a better and more tailored use of therapeutic drugs both in companion and food‐producing animals. Nonlinear mixed effects (NLME) have been purposely designed to characterize the sources of variability in drug disposition and response. The NLME approach can be used to explore the impact of population‐associated variables on the relationship between drug administration, systemic exposure, and the levels of drug residues in tissues. The latter, while different from the method used by the US Food and Drug Administration for setting official withdrawal times (WT) can also be beneficial for estimating WT of approved animal drug products when used in an extralabel manner. Finally, NLME can also prove useful to optimize dosing schedules, or to analyze sparse data collected in situations where intensive blood collection is technically challenging, as in small animal species presenting limited blood volume such as poultry and fish.     

How to extrapolate a withdrawal time from an EHSLC published detection time: A Monte Carlo simulation appraisal

Reason for performing study: For legitimate medications, veterinarians must advise the owners or trainers of horses on appropriate withholding times after a treatment, to avoid the risk of incurring a positive drug test. Objective: To explore the safety span to select that a veterinarian may extrapolate a tailored withdrawal time (WT) from a generic detection time (DT) as published by the European Horserace Scientific Liaison Committee (EHSLC). Methods: Using Monte Carlo simulations, it was shown that for a low variability of pharmacokinetic parameters (CV = 20%), an uncertainty span of about 40% may be selected to transform a mean DT into a WT (i.e. WT = 1.4 DT), which covers 90% of the horse population. In contrast for a highly variable drug (CV = 40%), an uncertainty factor of about 2.1–2.2 needs to be selected, i.e. a WT that is twice the DT. Results: The relative impact of the different factors of variability on the final WT was documented by a so‐called sensitivity analysis. It was shown that the parameters that have the greatest influence on the value of a DT are those that control the terminal half‐life of the drug disposition. In contrast, parameters controlling the level of urine (or plasma) concentrations (i.e. the actual administered dose, the urine‐to‐plasma ratio and the bioavailability) collectively have a minimal influence on the DT. Conclusions and potential relevance: In practice, this means that the main sources of uncertainty are of biological origin and cannot be reduced by any managerial options. The influence of the number of experimental horses that are used by EHSLC to establish a DT was shown that with the standard EHLSC protocol of 6 horses, half of the trials lead to a proposed DT that is equal to or higher than the population 90^th percentile. Increasing the number of investigated horses to 8 and 10 would increase this last probability to 85 and 90%, respectively.     

Contextual influences on animal decision‐making: Significance for behavior‐based wildlife conservation and management

Survival and successful reproduction require animals to make critical decisions amidst a naturally dynamic environmental and social background (i.e. “context”). However, human activities have pervasively, and rapidly, extended contextual variation into evolutionarily novel territory, potentially rendering evolved animal decision‐making mechanisms and strategies maladaptive. We suggest that explicitly focusing on animal decision‐making (ADM), by integrating and applying findings from studies of sensory ecology, cognitive psychology, behavioral economics and eco‐evolutionary strategies, may enhance our understanding of, and our ability to predict how, human‐driven changes in the environment and population demography will influence animal populations. Fundamentally, the decisions animals make involve evolved mechanisms, and behaviors emerge from the combined action of sensory integration, cognitive mechanisms and strategic rules of thumb, and any of these processes may have a disproportionate influence on behavior. Although there is extensive literature exploring ADM, it generally reflects a canalized, discipline‐specific approach that lacks a unified conceptual framework. As a result, there has been limited application of ADM theory and research findings into predictive models that can enhance management outcomes, even though it is likely that the relative resilience of species to rapid environmental change is fundamentally a result of how ADM is linked to contextual variation. Here, we focus on how context influences ADM, and highlight ideas and results that may be most applicable to conservation biology.     

Inter‐group associations in Mongolian gerbils: Quantitative evidence from social network analysis

Animals often interact non‐randomly with conspecifics, and association preferences can differ across life‐history stages to maximize individuals' fitness. Mongolian gerbils (Meriones unguiculatus) are a social rodent that live in highly seasonal habitats and display seasonal fluctuations in population density, growth rate and the size of overlapped home ranges. Nevertheless, whether gerbils modify their social relationships at different life‐history stages remains unknown. Here, we used social network analysis to examine whether social associations differ between the sexes and between life‐history stages in a wild population of Mongolian gerbils. We quantified social attributes at both group level (assortativity) and individual level (social differentiation and degree, closeness and betweenness centrality); these attributes reflect individuals' social preferences and their potential influence on others in the network. We found that both male and female gerbils established fewer inter‐group social connections during the food‐hoarding season than during the breeding season, revealing constraints on sociality. Similarly, during the food‐hoarding season, degree centrality and social differentiation increased significantly whereas closeness and betweenness centrality decreased significantly. Together, these results suggest that gerbils have relatively more partners and preferred associations and decreased influence over others in the network during the food‐hoarding season. In addition, we found no significant difference in any of the social attribute between males and females, but there was a significant interaction effect between sex and season on degree, closeness and betweenness centrality. Our results demonstrate that Mongolian gerbils adjust their association strategies to adapt to the changes of life history. Such adjustments may balance the costs/benefits associated with survival and reproduction.     

Effect of non‐starch‐polysaccharide‐degrading enzymes as feed additive on the rumen bacterial population in non‐lactating cows quantified by real‐time PCR

The effects of non‐starch‐polysaccharide‐degrading enzymes, added to a maize silage‐ and grass silage‐based total mixed ration (TMR) at least 14 h before feeding, on the rumen bacterial population were investigated. Six non‐lactating Holstein Friesian cows were allocated to three treatment groups using a duplicate 3 × 3 Latin square design with three 31‐day periods (29 days of adaptation and 2 days of sampling). Treatments were control TMR [69% forage and 31% concentrates on a dry matter (DM) basis] or TMR with 13.8 or 27.7 ml/kg of feed DM of Roxazyme G2 liquid with activities (U/ml enzyme preparation) of xylanase 260 000, β‐glucanase 180 000 and cellulase 8000 (DSM Nutritional Products, Basel, Switzerland). The concentrations of 16S rDNA of Anaerovibrio lipolytica, Fibrobacter succinogenes, Prevotella ruminicola, Ruminococcus flavefaciens, Selenomonas ruminantium and Treponema bryantii, and their relative percentage of total bacteria in rumen samples obtained before feeding and 3 and 7 h after feeding and from two rumen fractions were determined using real‐time PCR. Sampling time had only little influence, but bacterial numbers and the composition of the population differed between the transition layer between rumen fluid and the fibre mat (fraction A) and the rumen fluid (fraction B) highlighting the importance to standardize sampling. The 16S rDNA copies of total bacteria and the six bacterial species as well as the population composition were mainly unaffected by the high levels of exogenous enzymes supplemented at all sampling times and in both rumen fractions. Occasionally, the percentages of the non‐fibrolytic species P. ruminicola and A. lipolytica changed in response to enzyme supplementation. Some increases in the potential degradability of the diet and decreases in lag time which occurred collaterally indicate that other factors than changes in numbers of non‐particle‐associated bacteria are mainly responsible for the effects of exogenous enzymes.     

A comparison of 12‐ and 19‐week CHOP protocols using non‐randomized,contemporaneous controls

This study is a concurrent comparison of two versions of CHOP protocols, a 19‐week CHOP and a comparatively overall dose‐intense 12‐week CHOP. The 12‐week protocol was designed to be 58% more dose intense than the 19‐week protocol for both doxorubicin and cyclophosphamide; however, it was 21% less dose intense for vincristine (VCR). Forty‐seven dogs were included for evaluation, and the characteristics of each population were similar. For dogs receiving the 19‐week CHOP protocol, 89.5% experienced a complete response, with a median progression‐free survival (PFS) of 245 days and median overall survival (OS) of 347 days. For dogs receiving the 12‐week CHOP protocol, 89.3% experienced a complete response, with a median PFS of 141 days and median OS of 229 days. When evaluated by Log‐rank analysis, the difference of PFS (P = 0.047) and OS (P = 0.013) between the groups were statistically significant. In summary, these data suggest that despite overall increased dose‐intensity, dogs receiving treatment with a 12‐week CHOP protocol experience less durable remission than our standard 19‐week protocol in this population. Additional prospective investigation will be required to explore the implication that VCR dose intensity and/or shorter overall temporal drug exposure in this protocol may result in diminished efficacy.     

Human‐mediated Foot‐and‐mouth Disease Epidemic Dispersal: Disease and Vector Clusters

Disease clusters were retrospectively explored at national level using a geo‐referenced dataset from the 2001 Uruguayan Foot‐and‐Mouth Disease (FMD) epidemic. Disease location and time (first 11 epidemic weeks) were analysed across 250 counties (of which 160 were infected), without and with control for human mobility related factors (human population and road densities). The null hypothesis of random disease distribution over space and/or time was assessed with: (i) purely temporal; (ii) purely spatial; and (iii) space/time tests. At least within epidemic weeks 2 and 6, a principal disease cluster was observed in 33 contiguous counties (P < 0.01). Two secondary clusters, located at >100 km from each other, were also observed (P < 0.01). The purely spatial test that controlled for human population density identified two non‐contiguous clusters (P < 0.01). Space and time analysis also revealed the same 33 counties as members of the principal cluster, of which 31 were also clustered when human population was controlled (P < 0.01). No clusters were reported by the spatial test when road density was assessed. The hypothesis that human mobility related factors autocorrelate with disease was empirically supported by two pieces of information: (i) removal of human population/road densities eliminated >93.9% of the counties included in the principal disease cluster; and (ii) statistically significant correlations (P < 0.05) were observed in the first three epidemic weeks between road density and the number of cases. Clusters where human population density was associated with 47% greater number of cases/sq. km than that of the principal cluster indicated possible roles as disease vectors (vector clusters). Selective control policy in vector clusters is recommended. Periodic (i.e. weekly) cluster and correlation analyses of both disease and other covariates may facilitate disease surveillance and help design space‐specific control policy.     

Embryonic and post‐embryonic responses to high‐elevation hypoxia in a low‐elevation lizard

Low‐elevation species can migrate toward higher elevations to survive in a warming world. However, animals’ responses to hypoxia when migrating to high elevations have rarely been addressed. To identify the response of low‐elevation lizards to high‐elevation hypoxia, we collected field body temperatures (T_fb) and operative temperatures (T_e) of lizards (Eremias argus) from a low‐elevation population (1036 m) and a high‐elevation population (2036 m), and then determined adult thermal physiology, embryonic development, and hatchling phenotypes after acclimating low‐elevation lizards and incubating their eggs in conditions mimicking the low‐elevation oxygen condition (18.5% O₂) and high‐elevation oxygen (hypoxic) condition (16.5% O₂). Our study revealed that T_fb and T_e were higher for the low‐elevation population compared to the high‐elevation population. We also found adults from low elevation acclimated to hypoxia preferred lower body temperatures, but did not show changes in locomotor performance or growth. In addition, hypoxia did not affect embryonic development (hatching time and success) or hatchling phenotypes (body size and locomotor performance). These results suggest that adult lizards from low elevations can respond to hypoxia‐induced stress when migrating to high elevations by behaviorally thermoregulating to lower body temperatures in order to sustain normal functions. Similarly, low‐elevation embryos can develop normally (with unchanged hatching success and offspring phenotypes) under the high‐elevation hypoxic condition. This study highlights that low‐elevation populations of a species that inhabits a range of elevations can buffer the impact of high‐elevation hypoxic conditions to some degree and thus attain similar fitness to the source population.     

Multidrug‐Resistant Outbreak‐Associated Salmonella Strains in Irrigation Water from the Metropolitan Region,Chile

Salmonella enterica (S. enterica) is the main cause of foodborne diseases in the Chilean population. With the aim of characterizing the presence of S. enterica in bodies of water, samples from 40 sources were obtained, including rivers and irrigation canals used by agricultural farms in the most populated regions of Chile. As result, 35 S. enterica isolates belonging to several serotypes were detected, with the highest frequency represented by Typhimurium and Enteritidis. All strains showed phenotypic antimicrobial resistance, and most of them were multiresistant to critically important antimicrobials. In addition, the pulse‐field gel electrophoresis analysis using XbaI and BlnI endonucleases showed that seven Salmonella isolates belonging to serotypes Typhimurium, Enteritidis and Infantis had identical pulsotypes to outbreak‐associated clinical isolates detected in the Chilean population, suggesting a public health risk of water pollution in this region. Among sampling sites, the higher detection rates were observed in rural than urban and peri‐urban areas, suggesting that the animal husbandry might contribute for environmental dispersion of this pathogen. Future efforts should address the characterization of cause‐and‐effect relationship between water contamination and foodborne disease, including the implementation of surveillance programmes to tackle potential risks for both human and animal populations.     

Contrasting effects of heat shock during in vitro maturation on development of in vitro‐fertilized and parthenogenetic bovine embryos

This study investigated the influence of heat shock during in vitro maturation on embryo development following in vitro fertilization (IVF) or parthenogenesis (Part). Immature bovine cumulus–oocyte complexes were exposed to heat shock (41.0°C) during the first 12 hr of in vitro maturation (IVM), followed by 12 hr at 38.5°C. Control group consisted of in vitro maturation for 24 hr at 38.5°C. Oocytes were in vitro‐fertilized or activated with ionomycin and cultured in vitro for 192 hr post‐in vitro insemination or parthenogenetic activation (hpia). There was an interaction (p < .01) between temperature of IVM and method of oocyte activation (IVF or Part) for cleavage at 48 hpia. Heat shock had a negative impact (p < .01) on cleavage of IVF embryos, whereas no (p > .05) effect was found in the Part embryos. Embryo development towards blastocyst stage at 168 and 192 hpia decreased in both IVF and Part embryos derived from heat‐shocked oocytes. Heat shock increased (p < .05) the apoptotic index in Part blastocysts, but no effect (p > .05) was found in IVF counterparts. Heat shock also down‐regulated the expression of AQP3 (p < .01) and up‐regulated the expression of HSP70.1 (p < .01) in Part blastocysts, whereas it down‐regulated the expression of ATP1A1 (p < .05) in IVF blastocysts. In conclusion, the effects of heat shock during IVM on early embryo cleavage and blastocyst apoptosis are influenced by the method of oocyte activation and expression of some genes can be disturbed in embryos derived from heat‐shocked oocytes.     

A systematic review and meta‐analysis of predictors of human hepatitis E virus exposure in non‐endemic countries

The reported incidence of clinical hepatitis E cases is rising in some non‐endemic countries, with concurrent concerns regarding potential hepatitis E virus (HEV) contamination of the blood supply. Therefore, the characterization of major potential sources of human HEV exposure is important to inform risk assessment and public health policy. A systematic review was conducted, including a comprehensive search in six electronic bibliographic databases, verified by hand‐searching reference lists of HEV reviews, and a grey literature search, of the broad research question ‘what is the evidence of the association between predictors of human HEV exposure, and HEV IgG seropositivity, in non‐endemic countries?’ Using forms designed a priori, captured studies were appraised at first‐level screening, second‐level characterization, and third‐level data extraction and risk of bias assessment. Meta‐analysis yielded summary estimates of association between potential predictors and odds of HEV seropositivity. Meta‐analysis and meta‐regression of the odds of HEV seroprevalence in specific groups characterized potential sources of HEV exposure. From 4,163 captured citations, 245 relevant studies underwent data extraction, investigating HEV seroprevalence or predictors in both healthy subjects and targeted patient groups. Across these groups, increasing age was a predictor of HEV IgG seropositivity. Both human immunodeficiency virus patients and haemodialysis patients had significantly increased odds of HEV seropositivity relative to the general population. Working with pigs, in forestry, or in hospitals, was significantly associated with increased odds of HEV seropositivity, as were consumption of meat, pork or game meat, or hunting. Chronological time was not associated with HEV seropositivity within our data sets. Further study of the distribution of potential dietary or behavioural predictors between high and lower prevalence areas within non‐endemic countries could improve our understanding of the relative importance of specific HEV transmission pathways.     

The Influence of Restricted Feeding on Glucagon‐Like Peptide‐1 (GLP‐1)‐Containing Cells in the Chicken Small Intestine

The influence of restricted feeding on the distribution of glucagon‐like peptide‐1 (GLP‐1)‐containing endocrine cells in the chicken small intestine was investigated using immunohistochemical and morphometrical techniques. This study demonstrated that the restricted feeding had an influence on the activity of GLP‐1‐immunoreactive cells in the chicken small intestine. There were differences in the localization and the frequency of occurrence of GLP‐1‐immunoreactive cells in the small intestine between control and restricted groups, especially 25% feed supply group provided with 25% of the intake during the adapting period. GLP‐1‐immunoreactive cells in the control chickens were mainly located in epithelium from crypts to the lower part of intestinal villi. Those in restricted groups, however, tended to be located from crypts to the middle part of intestinal villi. The frequency of occurrence of GLP‐1‐immunoreactive cells was lowest in the control group, medium in 50% feed supply group and highest in 25% feed supply group at each intestinal region examined in this study, that is, increased with the advancement of restricting the amount of feed supply. These data show that the quantity of food intake is one of signals that have an influence on the secretion of GLP‐1 from L cells in the chicken small intestine.     

Within‐ and across‐breed imputation of high‐density genotypes in dairy and beef cattle from medium‐ and low‐density genotypes

The objective of this study was to evaluate, using three different genotype density panels, the accuracy of imputation from lower‐ to higher‐density genotypes in dairy and beef cattle. High‐density genotypes consisting of 777 962 single‐nucleotide polymorphisms (SNP) were available on 3122 animals comprised of 269, 196, 710, 234, 719, 730 and 264 Angus, Belgian Blue, Charolais, Hereford, Holstein‐Friesian, Limousin and Simmental bulls, respectively. Three different genotype densities were generated: low density (LD; 6501 autosomal SNPs), medium density (50K; 47 770 autosomal SNPs) and high density (HD; 735 151 autosomal SNPs). Imputation from lower‐ to higher‐density genotype platforms was undertaken within and across breeds exploiting population‐wide linkage disequilibrium. The mean allele concordance rate per breed from LD to HD when undertaken using a single breed or multiple breed reference population varied from 0.956 to 0.974 and from 0.947 to 0.967, respectively. The mean allele concordance rate per breed from 50K to HD when undertaken using a single breed or multiple breed reference population varied from 0.987 to 0.994 and from 0.987 to 0.993, respectively. The accuracy of imputation was generally greater when the reference population was solely comprised of the breed to be imputed compared to when the reference population comprised of multiple breeds, although the impact was less when imputing from 50K to HD compared to imputing from LD.     

Prevalence of hepatitis E virus infection among people and swine in mainland China: A systematic review and meta‐analysis

Hepatitis E virus (HEV) infection remains an important public health problem, and it is endemic primarily in developing countries. This study aimed to evaluate the seroprevalence of HEV among the general population, occupational population and swine in mainland China and its risk factors based on a systematic review and meta‐analysis. Systematic search from EMBASE, PubMed, Web of Science, Cochrane Library and several Chinese databases, such as Wanfang (WF) Data, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP) and SINOMED, was searched from inception up to 25 April 2018. The overall seroprevalence of HEV and its corresponding 95% confidence interval (CI) as well as the correlation coefficients between different groups were estimated using stata 12.0 and r ‐3.4.1 software. Potential sources of heterogeneity were explored using subgroup and sensitivity analyses. Twenty‐eight studies with 57,274 participants (including human and swine) were included. The seroprevalence of anti‐HEV immunoglobulin G (IgG) among the general population, occupational population and swine was 27.3% (95% CI: 22.4–32.2), 47.4% (95% CI: 40.1–54.8) and 66.4% (95% CI: 61.7–71.1), respectively. The overall prevalence of IgM among the general population was 1.8% (95% CI: 0.7–2.9). The odds ratio for the occupational population, as compared to the general population, was 2.63. The highest anti‐HEV IgG prevalence (59%) was observed in East China, whereas the lowest (34.8%) was noted in Northeast and North China. In the occupational population, the highest prevalence (77.0%) was observed among swine vendors. Seven studies included 30,392 participants (humans and swine); the correlation coefficient for the prevalence of anti‐HEV IgG between the professional population and adult pigs was 0.88. Sensitivity analyses showed that the stability of results was not considered significant. This research found that HEV is common in China, and contact with pork or other pig products may be an important mode of HEV transmission.     

Effects of dietary heme iron and exercise training on abdominal fat accumulation and lipid metabolism in high‐fat diet‐fed mice

Animal by‐products can be recycled and used as sources of essential nutrients. Water‐soluble heme iron (WSHI), a functional food additive for supplementing iron, is produced by processing animal blood. In this study, we investigated the effects of dietary supplementation of 3% WSHI and exercise training for 4 weeks on the accumulation of abdominal fat and lipid metabolism in mice fed high‐fat diet. Exercise‐trained mice had significantly less perirenal adipose tissue, whereas WSHI‐fed mice tended to have less epididymal adipose tissue. In addition, total weight of abdominal adipose tissues was significantly decreased in the Exercise + WSHI group. Dietary WSHI significantly increased the messenger RNA (mRNA) levels of lipoprotein lipase and hormone‐sensitive lipase. WSHI‐fed mice also tended to show increased mRNA levels of adipose triglyceride lipase in their epididymal adipose tissue. Dietary WSHI also significantly decreased the mRNA levels of fatty acid oxidation‐related enzymes in the liver, but did not influence levels in the Gastrocnemius muscle. Exercise training did not influence the mRNA levels of lipid metabolism‐related enzymes in the epididymal adipose tissue, liver or the Gastrocnemius muscle. These findings suggest that the accumulation of abdominal fat can be efficiently decreased by the combination of dietary WSHI and exercise training in mice fed high‐fat diet.     

Estimating heritability of wool shedding in a cross‐bred ewe population

Low wool prices and high production costs in sheep systems have resulted in the introduction of genotypes that shed wool into flocks to reduce shearing costs. Wool shedding occurs naturally in a few breeds and can be incorporated by cross‐breeding. The opportunity to enhance shedding through selection depends on the extent of genetic variability present. Genetic and environmental parameters for wool shedding for ewes from a three‐breed composite population were estimated using Bayesian inference. Data on 2025 cross‐bred ewes, including 3345 wool shedding scores (WS) and 1647 breeding weight (BW) records, were analysed using bivariate and, for WS, univariate animal repeatability models. Breeding weight was included to account for possible selection bias. Breeding weight was moderately heritable and highly repeatable with means of 0.317 and 0.724, respectively. Under both models, WS was found to be moderately heritable and repeatable with means of 0.256 and 0.399, respectively. Based on a cumulative link model and contingency table analysis, age and reproductive activity influenced the extent of WS (p < 0.05). Given that WS is moderately heritable, selective gain in WS can be achieved.