Genomic, microbial and environmental standardization in animal experimentation limiting immunological discovery.

BACKGROUND: The use of inbred mice housed under standardized environmental conditions has been critical in identifying immuno-pathological mechanisms in different infectious and inflammatory diseases as well as revealing new therapeutic targets for clinical trials. Unfortunately, only a small percentage of preclinical intervention studies using well-defined mouse models of disease have progressed to clinically-effective treatments in patients. The reasons for this lack of bench-to-bedside transition are not completely understood; however, emerging data suggest that genetic diversity and housing environment may greatly influence muring immunity and inflammation. RESULTS: Accumulating evidence suggests that certain immune responses and/or disease phenotypes observed in inbred mice may be quite different than those observed in their outbred counterparts. These differences have been thought to contribute to differing immune responses to foreign and/or auto-antigens in mice vs. humans. There is also a growing literature demonstrating that mice housed under specific pathogen free conditions possess an immature immune system that remarkably affects their ability to respond to pathogens and/or inflammation when compared with mice exposed to a more diverse spectrum of microorganisms. Furthermore, recent studies demonstrate that mice develop chronic cold stress when housed at standard animal care facility temperatures (i.e. 22-24 °C). These temperatures have been shown alter immune responses to foreign and auto-antigens when compared with mice housed at their thermo-neutral body temperature of 30-32 °C. CONCLUSIONS: Exposure of genetically diverse mice to a spectrum of environmentally-relevant microorganisms at housing temperatures that approximate their thermo-neutral zone may improve the chances of identifying new and more potent therapeutics to treat infectious and inflammatory diseases.

Bem-estar dos cães de abrigos municipais no estado do Paraná, Brasil, segundo o protocolo Shelter Quality / The welfare of dogs from municipal shelters in the state of Paraná, Brazil, under the Shelter Quality protocol

O bem-estar dos animais, além dos aspectos individuais, depende do entendimento e dedicação dos responsáveis pelo abrigo. O objetivo do presente trabalho foi avaliar o bem-estar dos cães mantidos em abrigos municipais do estado do Paraná, mediante a aplicação do protocolo Shelter Quality. Foram avaliados 16 abrigos, 439 cães e 165 recintos, na estação do outono de 2017. A maioria dos abrigos apresentou cães com condição corporal adequada e pelagem limpa, em recintos seguros, com metragem e suprimento de água adequados e conforto térmico. Além disso, a maioria dos cães eram mantidos em recintos coletivos e em ambientes abertos, com baixo nível de ruído e demonstravam mais emoções positivas, desejáveis na adoção. Como aspectos negativos, 58% (96/165) dos recintos avaliados tinham camas inadequadas ou inexistentes e 30% (50/165) dos recintos mantinham cães individualmente, sendo indicadores de baixo grau de bem-estar para os cães envolvidos. Além disso, nenhum abrigo disponibilizava ração para cães idosos e 81% (13/16) dos abrigos negligenciavam o diagnóstico e tratamento da dor. Apesar de a maioria dos abrigos apresentarem mais pontos positivos que negativos em sua avaliação, a gestão dos abrigos deve sempre visar à correção dos pontos críticos que comprometam o bem-estar dos animais.(AU)

Animal welfare, in addition to individual aspects, depends on the understanding and dedication of those responsible for the shelter. The objective of this study was to evaluate the welfare of dogs kept in municipal shelters in the state of Paraná, using the Shelter Quality protocol. A total of 16 shelters, 439 dogs and 165 enclosures were evaluated in the fall season of 2017. Most shelters presented dogs with adequate body condition and clean coat, in secure enclosures with adequate water supply and thermal comfort. In addition, most dogs were kept in collective enclosures and in open environments, with low noise levels and showing more positive, desirable emotions in adoption. As negative aspects, 58% (96/165) of the precincts evaluated had inadequate or inexistent beds and 30% (50/165) of the enclosures kept dogs individually, being indicators of a low degree of well-being for the dogs involved. In addition, no shelter provided elderly dog rations and 81% (13/16) of the shelters neglected the diagnosis and treatment of pain. Although most shelters present more positive than negative points in their evaluation, shelter management should always aim at correcting critical points that compromise animal welfare.(AU)

Long-Term Study on the Effects of Housing C57BL/6NCrl Mice in Cages Equipped With Wireless Technology Generating Extremely Low-Intensity Electromagnetic Fields.

The recent development of mouse cages equipped with monitoring wireless technology raised questions on the potential effects on animals induced by electromagnetic fields (EMFs) generated by electronic boards positioned underneath the cages. The aims of this study were to characterize the EMF produced by digitally ventilated cages (DVC) and perform a clinicopathological study on mice maintained in DVC for up to 1 year. The EMFs were measured in empty individually ventilated cages (IVC) and DVC. Male (n = 160) and female (n = 160) C57BL/6NCrl mice were randomly housed in IVC and DVC in a single rack, 4 mice per cage. Body weight and food and water consumption were recorded at 14-day intervals. At sacrifice (days 60, 120, 180, and 365), body and testes weight was measured, and necropsy, hematology, bone marrow cytology, histology, and immunohistochemistry for cleaved-caspase 3 on the testes were performed. Digitally ventilated cages produced extremely low-intensity electric fields ranging from 5 Hz to 3 GHz. No exposure-related clinical signs and mortality occurred. Occasional statistical differences in body weight, food and water consumption, hematology, bone marrow, and histopathology were recorded, but considered without biological or clinical relevance. In conclusion, long-term maintenance in DVC had no definite effects on C57BL/6NCrl mice.

Lab-Scale Model to Evaluate Odor and Gas Concentrations Emitted by Deep Bedded Pack Manure.

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs used in cattle mono-slope facilities. This protocol has been used to effectively evaluate many different bedding materials, environmental variables (temperature, humidity), and potential mitigation treatments that can improve air quality in commercial deep-bedded mono-slope facilities. The model is dynamic and allows researchers to easily collect many chemical and physical measurements from the bedded pack. Weekly measurements, collected over the course of six to seven weeks, allows sufficient time to see changes in air quality measurements over time as the bedded pack matures. The data collected from the simulated bedded packs is within the range of concentrations previously measured in commercial deep-bedded mono-slope facilities. Past studies have demonstrated that 8 - 10 experimental units per treatment are sufficient to detect statistical differences among the simulated bedded packs. The bedded packs are easy to maintain, requiring less than 10 minutes of labor per bedded packs per week to add urine, feces, and bedding. Sample collection using the gas sampling system requires 20 - 30 minutes per bedded pack, depending on the measurements that are being collected. The use of lab-scaled bedded packs allows the researcher to control variables such as temperature, humidity, and bedding source that are difficult or impossible to control in a research or commercial facility. While not a perfect simulation of "real-world" conditions, the simulated bedded packs serve as a good model for researchers to use to examine treatment differences among bedded packs. Several lab-scale studies can be conducted to eliminate possible treatments before trying them in a research or commercial-sized facility.

Shelter housing for cats: Principles of design for health, welfare and rehoming.

Practical relevance: Shelters and rehoming centres are a valuable tool in the population management and rehoming of cats. However, housing large numbers of a relatively asocial species in close proximity poses significant challenges. Well-designed accommodation enables improved standards of husbandry, as well as a better working environment for staff. This can have a significant benefit in expediting rehoming, as cats are healthier, and more likely to display natural behaviors and have positive interactions with potential adopters. Global importance: As cat overpopulation is such a widespread issue, cat shelters are common in many countries. This review will be of interest to those involved in the design and construction of cat shelters, and to those caring for the cats within them. The principles discussed also apply to boarding, breeding, research and hospitalization facilities. Challenges: Shelter housing poses substantial challenges in terms of maintaining positive health and wellbeing while sustaining adoption at an optimum rate. Disease control and biosecurity are typically facilitated by having a relatively barren, easily cleanable environment. However, this must be weighed against the provision of opportunities for cats to perform natural behaviors such as hiding, perching and interacting if they wish. A more enriched environment has also been shown to expedite adoption. AIMS: This review, the first in a two-part series, discusses practical aspects of housing and shelter design for the health, welfare and adoption of shelter cats. Evidence base: There is a relatively small body of empirical evidence to inform shelter design recommendations. The recommendations in this article are based on a careful review of the available evidence, some of which has come from allied fields such as the care of experimental animals. Where evidence is not yet available, recommendations have been based on field experience and collective expert opinion.

Shelter housing for cats: Practical aspects of design and construction, and adaptation of existing accommodation.

Practical relevance: Not every cat shelter will have purpose-built accommodation but housing designed with the basic needs of cats in mind, whether purpose-built or adapted from existing housing, will improve the experience of cats passing through the facility. Challenges: Designing and building accommodation for cats in shelters should be a thoughtful process. There is a range of different housing types available. A variety of factors, such as expected length of stay, type of cat, cost and disease risk, will influence which design is most appropriate. AIMS: This review, the second in a two-part series, provides an overview of some of the essential requirements for housing shelter cats, either singly or in groups. Specific practical aspects of housing, including design, space allowances, cage furnishings and suitable construction materials, are discussed, and suggestions made for upgrading existing housing where extensive rebuilding is not feasible or realistic. Evidence base: There is a relatively small body of empirical evidence to inform shelter design recommendations. The recommendations in this article are based on a careful review of the available evidence, some of which has come from allied fields such as the care of experimental animals. Where evidence is not yet available, recommendations have been based on field experience and collective expert opinion.

Normal feline behaviour: and why problem behaviours develop.

Practical relevance: Cats are descended from a solitary, territorial ancestor, and while domestication has reduced their inherited tendency to be antagonistic towards all animals larger than their typical prey, they still place more reliance on the security of their territory than on psychological attachments to people or other cats, the exact opposite to dogs. Many feline problem behaviours stem from perceived threats to this security, often due to conflicts with other cats. Others are more developmental in origin, often caused by inadequate exposure to crucial stimuli, especially people, during the socialisation period. Strongly aversive events experienced at any age can also contribute. A third category comprises normal behaviour that owners deem unacceptable, such as scratching of furniture. Evidence base: This review identifies three areas in which basic research is inadequate to support widely employed concepts and practices in feline behavioural medicine. First, classification of cats' problem behaviours relies heavily on approaches derived from studies of their behavioural ecology and, to some extent, extrapolation from canine studies. Few studies have focused on cats in the home, the environment in which most behavioural disorders are expressed. Secondly, cats' chemical senses (olfactory and vomeronasal) are far more sensitive than our own, making it difficult for owners or clinicians to fully comprehend the sensory information upon which they base their behaviour. Thirdly, although the concept of psychological distress is widely invoked as an intervening variable in behavioural disorders, there are still no reliable measures of distress for pet cats in the home. Global importance: Psychological distress of some kind is the primary cause of many of the behavioural problems presented to clinicians, but surveys indicate that many more cats display the same clinical signs without their owners ever seeking help. The welfare of this 'invisible' group could be improved by veterinarians taking a more proactive approach to educating their clients about the behavioural needs of pet cats.

Warming the mouse to model human diseases.

Humans prefer to live within their thermal comfort or neutral zone, which they create by making shelters, wearing clothing and, more recently, by regulating their ambient temperature. These strategies enable humans to maintain a constant core temperature (a trait that is conserved across all endotherms, including mammals and birds) with minimal energy expenditure. Although this primordial drive leads us to seek thermal comfort, we house our experimental animals, laboratory mice (Mus musculus), under conditions of thermal stress. In this Review, we discuss how housing mice below their thermoneutral zone limits our ability to model and study human diseases. Using examples from cardiovascular physiology, metabolic disorders, infections and tumour immunology, we show that certain phenotypes observed under conditions of thermal stress disappear when mice are housed at thermoneutrality, whereas others emerge that are more consistent with human biology. Thus, we propose that warming the mouse might enable more predictive modelling of human diseases and therapies.

Improving reproducibility and external validity. The role of standardization and data reporting of laboratory rat husbandry and housing.

PURPOSE:: To identify the most relevant flaws in standardization in husbandry practices and lack of transparency to report them. This review proposes some measures in order to improve transparency, reproducibility and eventually external validity in experimental surgery experiments with rat model. METHODS:: We performed a search of scientific articles in PUBMED data base. The survey was conducted from august 2016 to January 2017. The keywords used were "reproducibility", "external validity", "rat model", "rat husbandry", "rat housing", and the time frame was up to January 2017. Articles discarded were the ones which the abstract or the key words did not imply that the authors would discuss any relationship of husbandry and housing with the reproducibility and transparency of reporting animal experiment. Reviews and papers that discussed specifically reproducibility and data reporting transparency were laboriously explored, including references for other articles that could fulfil the inclusion criteria. A total of 246 articles were initially found but only 44 were selected. RESULTS:: Lack of transparency is the rule and not the exception when reporting results with rat model. This results in poor reproducibility and low external validity with the consequence of considerable loss of time and financial resources. There are still much to be done to improve compliance and adherence of researchers, editors and reviewers to adopt guidelines to mitigate some of the challenges that can impair reproducibility and external validity. CONCLUSIONS:: Authors and reviewers should avoid pitfalls of absent, insufficient or inaccurate description of relevant information the rat model used. This information should be correctly published or reported on another source easily available for readers. Environmental conditions are well known by laboratory animal personnel and are well controlled in housing facilities, but usually neglected in experimental laboratories when the rat model is a novelty for the researcher.

The effects of individually ventilated cages on the respiratory systems of male and female Wistar rats from birth until adulthood

OBJECTIVE: To evaluate the respiratory systems of male and female rats maintained in individually ventilated cages (IVCs) from birth until adulthood. METHODS: Female Wistar rats were housed in individually ventilated cages or conventional cages (CCs) and mated with male Wistar rats. After birth and weaning, the male offspring were separated from the females and kept in cages of the same type until 12 weeks of age. RESULTS: The level of food consumption was lower in male offspring (IVC=171.7±9; CC=193.1±20) than in female offspring (IVC=100.6±7; CC=123.4±0.4), whereas the water intake was higher in female offspring (IVC=149.8±11; CC=99.2±0) than in male offspring (IVC=302.5±25; CC=249.7±22) at 11 weeks of age when housed in IVCs. The cage temperature was higher in individually ventilated cages than in conventional cages for both male (IVCs=25.9±0.5; CCs=22.95±0.3) and female (IVCs=26.2±0.3; CCs=23.1±0.3) offspring. The respiratory resistance (IVC=68.8±2.8; CC=50.6±3.0) and elastance (IVC=42.0±3.9; CC=32.4±2.0) at 300 µm/kg were higher in the female offspring housed in ventilated cages. The ciliary beat values were lower in both the male (IVCs=13.4±0.2; CC=15±0.4) and female (IVC=13.5±0.4; CC=15.9±0.6) offspring housed in individually ventilated cages than in those housed in conventional cages. The total cell (IVC=117.5±9.7; CC=285.0±22.8), neutrophil (IVC=13.1±4.8; CC=75.6±4.1) and macrophage (IVC=95.2±11.8; CC=170.0±18.8) counts in the bronchoalveolar lavage fluid were lower in the female offspring housed in individually ventilated cages than in those housed in conventional cages. CONCLUSIONS: The environmental conditions that exist in individually ventilated cages should be considered when interpreting the results of studies involving laboratory animals. In this study, we observed gender dimorphism in both the water consumption and respiratory mechanics of rats kept in ventilated cages.

Improving reproducibility and external validity. The role of standardization and data reporting of laboratory rat husbandry and housing

Abstract Purpose: To identify the most relevant flaws in standardization in husbandry practices and lack of transparency to report them. This review proposes some measures in order to improve transparency, reproducibility and eventually external validity in experimental surgery experiments with rat model. Methods: We performed a search of scientific articles in PUBMED data base. The survey was conducted from august 2016 to January 2017. The keywords used were "reproducibility", "external validity", "rat model", "rat husbandry", "rat housing", and the time frame was up to January 2017. Articles discarded were the ones which the abstract or the key words did not imply that the authors would discuss any relationship of husbandry and housing with the reproducibility and transparency of reporting animal experiment. Reviews and papers that discussed specifically reproducibility and data reporting transparency were laboriously explored, including references for other articles that could fulfil the inclusion criteria. A total of 246 articles were initially found but only 44 were selected. Results: Lack of transparency is the rule and not the exception when reporting results with rat model. This results in poor reproducibility and low external validity with the consequence of considerable loss of time and financial resources. There are still much to be done to improve compliance and adherence of researchers, editors and reviewers to adopt guidelines to mitigate some of the challenges that can impair reproducibility and external validity. Conclusions: Authors and reviewers should avoid pitfalls of absent, insufficient or inaccurate description of relevant information the rat model used. This information should be correctly published or reported on another source easily available for readers. Environmental conditions are well known by laboratory animal personnel and are well controlled in housing facilities, but usually neglected in experimental laboratories when the rat model is a novelty for the researcher.

Outdoor stocking density in free-range laying hens: radio-frequency identification of impacts on range use.

The number and size of free-range laying hen (Gallus gallus domesticus) production systems are increasing within Australia in response to consumer demand for perceived improvement in hen welfare. However, variation in outdoor stocking density has generated consumer dissatisfaction leading to the development of a national information standard on free-range egg labelling by the Australian Consumer Affairs Ministers. The current Australian Model Code of Practice for Domestic Poultry states a guideline of 1500 hens/ha, but no maximum density is set. Radio-frequency identification (RFID) tracking technology was used to measure daily range usage by individual ISA Brown hens housed in six small flocks (150 hens/flock - 50% of hens tagged), each with access to one of three outdoor stocking density treatments (two replicates per treatment: 2000, 10 000, 20 000 hens/ha), from 22 to 26, 27 to 31 and 32 to 36 weeks of age. There was some variation in range usage across the sampling periods and by weeks 32 to 36 individual hens from the lowest stocking density on average used the range for longer each day (P<0.001), with fewer visits and longer maximum durations per visit (P<0.001). Individual hens within all stocking densities varied in the percentage of days they accessed the range with 2% of tagged hens in each treatment never venturing outdoors and a large proportion that accessed the range daily (2000 hens/ha: 80.5%; 10 000 hens/ha: 66.5%; 20 000 hens/ha: 71.4%). On average, 38% to 48% of hens were seen on the range simultaneously and used all available areas of all ranges. These results of experimental-sized flocks have implications for determining optimal outdoor stocking densities for commercial free-range laying hens but further research would be needed to determine the effects of increased range usage on hen welfare.

A Protocol for Housing Mice in an Enriched Environment.

Environmental enrichment (EE) is a housing environment for mice that boosts mental and physical health compared to standard laboratory housing. Our recent studies demonstrate that environmental enrichment decreases adiposity, increases energy expenditure, resists diet induced obesity, and causes cancer remission and inhibition in mice. EE typically consists of larger living space, a variety of 'toys' to interact with, running wheels, and can include a number of other novel environmental changes. All of this fosters a more complex social engagement, cognitive and physical stimulations. Importantly, the toy location and type of toy is changed regularly, which encourages the mice to adapt to a frequently changing and novel environment. Many variables can be manipulated in EE to promote health effects in mice. Thus these approaches are difficult to control and must be properly managed to successfully replicate the associated phenotypes. Therefore, the goal of this video is to demonstrate how EE is properly set up and maintained to assure a complex, challenging, and controlled environment so that other researchers can easily reproduce the protective effects of EE against obesity and cancer.

Disinfectant choices in veterinary practices, shelters and households: ABCD guidelines on safe and effective disinfection for feline environments.

OVERVIEW: Regardless of whether a pathogen is viral, bacterial, parasitic, fungal or an emerging unknown, the mainstay of infectious disease control is hygiene, and the cornerstone of good hygiene is effective disinfection. CHALLENGES AND CURRENT CHOICES: Certain pathogens present a challenge to kill effectively: parvovirus, protozoal oocysts, mycobacteria, bacterial spores and prions resist most disinfectants but can be eliminated through heat, especially steam, which will kill protozoal oocysts. Heat is the safest and most effective disinfectant, but cannot be universally applied. Temperatures in washing machines and dishwashers should be at least 60 °C to eliminate pathogenic spores and resistant viruses. Enveloped viruses are susceptible to most disinfectants; of the non-enveloped viruses, parvovirus is recognised as being the most difficult to eradicate. Sodium hypochlorite is recommended for many applications: cleaning of floors, laundry, food preparation surfaces and utensils. Skin scrubs and rubs containing alcohols are more effective than those containing chlorhexidine, and less subject to contamination. DISINFECTANTS TO AVOID: Deficiency of the enzyme UDP-glucuronosyl transferase renders the cat susceptible to the toxic effects of phenol-based disinfectants (including many essential oils), so these should be avoided in feline environments. Quaternary ammonium compounds (eg, benzalkonium chloride) are also probably best avoided. THE FUTURE: Veterinary disinfection approaches in the future may include use of ultraviolet radiation and, increasingly, silver.

Borna disease virus infection in cats: ABCD guidelines on prevention and management.

OVERVIEW: Borna disease virus (BDV) has a broad host range, affecting primarily horses and sheep, but also cattle, ostriches, cats and dogs. In cats, BDV may cause a non-suppurative meningoencephalomyelitis ('staggering disease'). INFECTION: The mode of transmission is not completely elucidated. Direct and indirect virus transmission is postulated, but BDV is not readily transmitted between cats. Vectors such as ticks may play a role and shrews have been identified as a potential reservoir host. Access to forested areas has been reported to be an important risk factor for staggering disease. DISEASE SIGNS: It is postulated that BDV may infect nerve endings in the oropharynx and spread via olfactory nerve cells to the central nervous system. A strong T-cell response may contribute to the development of clinical disease. Affected cats develop gait disturbances, ataxia, pain in the lower back and behavioural changes. DIAGNOSIS: For diagnostic purposes, detection of viral RNA by reverse transcription PCR in samples collected from cats with clinical signs of Borna disease can be considered diagnostic. Serology is of little value; cats without signs of Borna disease may be seropositive and yet not every cat with BDV infection has detectable levels of antibodies. HUMAN INFECTION: A hypothesis that BDV infection may be involved in the development of selected neurological disorders in man could not be confirmed. A research group within the German Robert Koch Institute studied the potential health threat of BDV to humans and concluded that BDV was not involved in the aetiology of human psychiatric diseases.

Feline injection-site sarcoma: ABCD guidelines on prevention and management.

OVERVIEW: In cats, the most serious of adverse effects following vaccination is the occurrence of invasive sarcomas (mostly fibrosarcomas): so-called 'feline injection-site sarcomas' (FISSs). These develop at sites of previous vaccination or injection. They have characteristics that are distinct from those of fibrosarcomas in other areas and behave more aggressively. The rate of metastasis ranges from 10-28%. PATHOGENESIS: The pathogenesis of these sarcomas is not yet definitively explained. However, chronic inflammatory reactions are considered the trigger for subsequent malignant transformation. Injections of long-acting drugs (such as glucocorticoids, and others) have been associated with sarcoma formation. Adjuvanted vaccines induce intense local inflammation and seem therefore to be particularly linked to the development of FISS. The risk is lower for modified-live and recombinant vaccines, but no vaccine is risk-free. TREATMENT AND PREVENTION: Aggressive, radical excision is required to avoid tumour recurrence. The prognosis improves if additional radiotherapy and/or immunotherapy (such as recombinant feline IL-2) are used. For prevention, administration of any irritating substance should be avoided. Vaccination should be performed as often as necessary, but as infrequently as possible. Non-adjuvanted, modified-live or recombinant vaccines should be selected in preference to adjuvanted vaccines. Injections should be given at sites at which surgery would likely lead to a complete cure; the interscapular region should generally be avoided. Post-vaccination monitoring should be performed.

NDIR Gas Sensor for Spatial Monitoring of Carbon Dioxide Concentrations in Naturally Ventilated Livestock Buildings.

The tracer gas ratio method, using CO2 as natural tracer, has been suggested as a pragmatic option to measure emissions from naturally ventilated (NV) barns without the need to directly estimate the ventilation rate. The aim of this research was to assess the performance of a low-cost Non-Dispersive Infra-Red (NDIR) sensor for intensive spatial field monitoring of CO2 concentrations in a NV dairy cow house. This was achieved by comparing NDIR sensors with two commonly applied methods, a Photo-Acoustic Spectroscope (PAS) Gas Monitor and an Open-Path laser (OP-laser). First, calibrations for the NDIR sensors were obtained in the laboratory. Then, the NDIR sensors were placed in a dairy cow barn for comparison with the PAS and OP-laser methods. The main conclusions were: (a) in order to represent the overall barn CO2 concentration of the dairy cow barn, the number of NDIR sensors to be accounted for average concentration calculation was dependent on barn length and on barn area occupation; and (b) the NDIR CO2 sensors are suitable for multi-point monitoring of CO2 concentrations in NV livestock barns, being a feasible alternative for the PAS and the OP-laser methods to monitor single-point or averaged spatial CO2 concentrations in livestock barns.

Pen size and parity effects on maternal behaviour of Small-Tail Han sheep.

The aim of this experiment was to study the effects of pen size and parity on maternal behaviour of twin-bearing Small-Tail Han ewes. A total of 24 ewes were allocated to a 2×2 design (six per pen), with parity (primiparous or multiparous) and pen size (large: 6.0×3.0 m; small: 6.0×1.5 m) as main effects at Linyi University, Shandong Province, China. Behaviour was observed from after parturition until weaning. All ewes were observed for 6 h every 5 days from 0700 to1000 h and from 1400 to 1700 h. Continuous focal animal sampling was used to quantify the duration of maternal behaviours: sucking, grooming and following as well as the frequency of udder accepting, udder refusing and low-pitched bleating. Oestradiol and cortisol concentrations in the faeces (collected in the morning every 5 days) were detected using EIA kits. All lambs were weighed 24 h after parturition and again at weaning at 35 days of age. The small pen size significantly reduced following (P<0.005), grooming (P<0.001) and suckling durations (P<0.05), as well as the frequency of udder refusals (P<0.001). However, there was a significant interaction with ewe parity, with decreased grooming and suckling in the small pen largely seen in the multiparous ewes (P<0.001). Independent of pen size, multiparous ewes accepted more sucking attempts by their lambs (P<0.05) and made more low-pitched bleats than primiparous ewes (P<0.001). Multiparous ewes had higher faecal oestradiol concentrations than primiparous ewes (P<0.001), and ewes in small pens had higher faecal cortisol levels compared with ewes in larger pens (P<0.001). As lambs increased in age, the duration of maternal grooming, following and suckling as well as frequency of udder acceptance and low-pitched bleating all declined, and the frequency of udder refusing increased (P<0.001 for all). Ewe parity, but not pen size, affected lamb weight gain during the period of observation (P<0.001). This is the first study to show that pen size, interacting with parity, can affect the expression of maternal behaviour in sheep during lactation. The study is also the first to report on the maternal behaviour of Chinese native sheep breeds (Small-Tail Han sheep), with implications for the production of sheep in China.

Thermoneutral housing is a critical factor for immune function and diet-induced obesity in C57BL/6 nude mice.

OBJECTIVES: Obesity-related cancers represent public health burdens of the first order. Nevertheless, suitable mouse models to unravel molecular mechanisms linking obesity to human cancer are still not available. One translational model is the immunocompromised Foxn1 (winged-helix/forkead transcription factor) nude mouse transplanted with human tumor xenografts. However, most xenograft studies are conducted in nude mice on an in-bred BALB/c background that entails protection from diet-induced obesity. To overcome such resistance to obesity and its sequelae, we here propose the dual strategy of utilizing Foxn1 nude mice on a C57BL/6 background and housing them at their thermoneutral zone. METHODS: C57BL/6 nude and corresponding wild-type mice, housed at 23 or 33 °C, were subjected to either low-fat diet or high-fat diet (HFD). Energy expenditure, locomotor activity, body core temperature, respiratory quotient as well as food and water intake were analyzed using indirect calorimetry. Immune function at different housing temperatures was assessed by using an in vivo cytokine capture assay. RESULTS: Our data clearly demonstrate that conventional housing protects C57BL/6 nude mice from HFD-induced obesity, potentially via increased energy expenditure. In contrast, HFD-fed C57BL/6 nude mice housed at thermoneutral conditions develop adiposity, increased hepatic triglyceride accumulation, adipose tissue inflammation and glucose intolerance. Moreover, increased circulating levels of lipopolysaccharide-driven cytokines suggest a greatly enhanced immune response in C57BL/6 nude mice housed at thermoneutrality. CONCLUSION: Our data reveals mild cold stress as a major modulator for energy and body weight homeostasis as well as immune function in C57BL/6 nude mice. Adjusting housing temperatures to the thermoneutral zone may ultimately be key to successfully study growth and progression of human tumors in a diet-induced obese environment.