The influence of environment on development of the mucosal immune system

The mucosal immune system expresses active responses against pathogens and also tolerance against harmless food and commensal bacterial antigens. The mechanisms that determine which of these outcomes occur after recognition of antigens by T-cells are not clear. One possibility is that it is determined by the initial interaction between a dendritic and a na?ve T-cell in organised lymphoid tissue. However, such organised structures are, evolutionarily, quite recent and the original immune system must have made appropriate responses in more diffuse immunological architecture; a second possibility is that the critical interaction is between primed T-cells and their environment, in the lamina propria of the intestine. The mucosal immune system of neonates is poorly developed and inefficient at expressing appropriate immune responses. Development is influenced by a range of environmental factors including maternally derived antigen or antibody and commensal flora and pathogens. The intestine is a complex immunological structure in which the immune system and the macro- and microenvironment interact.     

The development and role of microbialhost interactions in gut mucosal immune development

At birth the piglet's immune system is immature and it is dependent upon passive maternal protection until weaning.The piglet's mucosal immune system develops over the first few weeks but has not reached maturity at weaning ages which are common on commercial farms. At weaning piglets are presented with a vast and diverse range of microbial and dietary/environmental antigens. Their ability to distinguish between antigens and mount a protective response to potential pathogens and to develop tolerance to dietary antigens is critical to their survival and failure to do so is reflected in the high incidence of morbidity and mortality in the post-weaning period. A growing recognition that the widespread use of antibiotics to control infection during this critical period should be controlled has led to detailed studies of those factors which drive the development of the mucosal immune system, the role of gut microbiota in driving this process, the origin of the bacteria that colonise the young piglet's intestine and the impact of rearing environment. This review briefly describes how the mucosal immune system is equipped to respond appropriately to antigenic challenge and the programmed sequence by which it develops. The results of studies on the critical interplay between the host immune system and gut microbiota are discussed along with the effects of rearing environment. By comparing these with results from human studies on the development of allergies in children, an approach to promote an earlier maturation of the piglet immune system to resist the challenges of weaning are outlined.     

Comparative approach to understanding traumatic injury in the immature, postnatal brain of domestic animals

Traumatic brain injury (TBI) is a frequent occurrence in veterinary medicine, but the mechanisms leading to brain damage after a head impact are incompletely understood, particularly in the postnatal immature and still developing nervous system. This paper reviews neurotrauma studies, largely in paediatric humans and experimental animal models, in order to outline the pathophysiological and biomechanical events likely to be operative in head trauma involving domestic animal species in the postnatal period, as there is almost no other information available in the veterinary literature. Predicting the outcome of TBI is particularly difficult at this developmental time, in large part because recovery is influenced by the stage of brain maturation and neuroplasticity. An important part of the clinical management of TBI is the differentiation of primary brain damage, which occurs at the moment of head impact and is largely refractory to treatment, from the cascade of secondary events, which evolve over time and are potentially preventable and amenable to therapeutic intervention. An understanding of the causes and consequences of secondary brain damage such as hypoxia-ischaemia, brain swelling, elevated intracranial pressure, and infection is critical to limiting the resulting brain injury.     

A review of oxalate poisoning in domestic animals: tolerance and performance aspects

Published data on oxalate poisoning in domestic animals are reviewed, with a focus on tolerance and performance. Oxalic acid is one of a number of anti‐nutrients found in forage. It can bind with dietary calcium (Ca) or magnesium (Mg) to form insoluble Ca or Mg oxalate, which then may lead to low serum Ca or Mg levels as well as to renal failure because of precipitation of these salts in the kidneys. Dietary oxalate plays an important role in the formation of Ca oxalate, and a high dietary intake of Ca may decrease oxalate absorption and its subsequent urinary excretion. Oxalate‐rich plants can be supplemented with other plants as forage for domestic animals, which may help to reduce the overall intake of oxalate‐rich plants. Non‐ruminants appear to be more sensitive to oxalate than ruminants because in the latter, rumen bacteria help to degrade oxalate. If ruminants are slowly exposed to a diet high in oxalate, the population of oxalate‐degrading bacteria in the rumen increases sufficiently to prevent oxalate poisoning. However, if large quantities of oxalate‐rich plants are eaten, the rumen is overwhelmed and unable to metabolize the oxalate and oxalate‐poisoning results. Based on published data, we consider that <2.0% soluble oxalate would be an appropriate level to avoid oxalate poisoning in ruminants, although blood Ca level may decrease. In the case of non‐ruminants, <0.5% soluble oxalate may be acceptable. However, these proposed safe levels of soluble oxalate should be regarded as preliminary. Further studies, especially long‐term studies, are needed to validate and improve the recommended safe levels in animals. This review will encourage further research on the relationships between dietary oxalate, other dietary factors and renal failure in domestic animals.     

TLR9 agonists: immune mechanisms and therapeutic potential in domestic animals

Toll like receptors (TLRs) are transmembrane glycoproteins that recognize conserved microbial molecules. Engagement of TLRs activates innate and adaptive immunity. TLR-mediated activation of immune cells results in upregulation of cytokines, chemokines and costimulatory molecules. These early innate responses control pathogen spread and initiates adaptive immune responses. Synthetic CpG oligodeoxynucleotides (ODN), agonists for TLR9, had shown great promise as immunotherapeutic agents and vaccine adjuvants in laboratory animal models of infectious disease, allergy and cancer. However, it has become apparent that CpG ODN are less potent immune activators in domestic animals and humans. The disparity in immune responses between rodents and mammals has been mainly attributed to differences in cellular expression of TLR9 in the various species. In this article, our current understanding of the immune mechanisms, as well as the potential applications of CpG ODN will be reviewed, with particular emphasis on domestic animals.     

The effect of management and psychosocial stress on the fetal and postnatal development of the domestic cat

A cattery consisting of 31 queens was divided into two groups. Group 1 remained in a location which they were accustomed to for years, while group 2 was exported to an environment of psychosocial and environmental stress. During the following seven months we observed four parturitions in group 1 and five parturitions in group 2. The new-born kittens in group 2 showed a significant lower birth weight and slower weight gain after the third week of lactation than group 1.     

免疫胶体金试剂盒检测家畜血吸虫病的效果及分析

目的观察浙江省农科院研制的免疫胶体金试剂盒对家畜血吸虫病检测效果。方法用试剂盒检测疫区放养耕牛、圈养猪和鸡的感染率及感染强度,同时用粪便毛蚴孵化法为标准,观察试剂盒的敏感和特异性。结果用免疫胶体金试剂盒于2005年和2006年间分别检测牛749头和613头,阳性率分别为55.4%和71.9%;检测圈养猪108头,鸡12只,阳性率分别为84.3%和91.7%;粪检检测出阳性牛18头,免疫胶体金的漏检率达33.3%;结论免疫胶体金技术检测家畜血吸虫病,假阳性率和假阴性率均很高,免疫胶体金试剂盒检测技术需进一步改进提高。     

家畜中枢神经系统神经肽的分布定位研究进展

本文简要综述了家畜中枢神经系统生长抑素、类阿片肽、血管活性肠多肽、胆囊收缩素、催产素和加压素、促黄体激素释放激素、脑钠肽和心钠肽、甘丙肽、神经肽Y和内皮素等神经肽的分布定位及生理作用 ,为进一步研究家畜生长、生殖和内分泌的调控机制提供了形态学资料     

The evolution of domestic pets and companion animals

The process of domestication, which began 12,000 years ago, before the beginnings of agriculture, continues as humans and domestic animals coexist, interact, and profoundly influence the shape of each other's social spaces. Although its beginnings were simple, this process has become increasingly complex. Attention to relationships between humans and companion animals commonly focuses on dogs and cats; however, companion animals and pets take various shapes in numerous places with and have diverse, overlapping functions and specializations.     

Regulation of ovarian folliculogenesis by IGF and BMP system in domestic animals

Involvement of insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) in ovarian folliculogenesis has been extensively studied during the last decade. In all mammalian species, IGF-I stimulates granulosa cell proliferation and steroidogenesis. The concentrations of IGF-I and -II do not vary during terminal follicular growth and atresia. In contrast, the levels of IGFBP-2 and -4, as well as IGFBP-5 in ruminants, dramatically decrease and increase during terminal follicular growth and atresia, respectively. These changes are responsible for an increase and a decrease in IGF bioavailability during follicular growth and atresia, respectively. They are partly explained by changes in ovarian expression. In particular, expression of IGFBP-2 mRNA decreases during follicular growth in ovine, bovine and porcine ovaries, and expression of IGFBP-5 mRNA dramatically increases in granulosa cells of bovine and ovine atretic follicles. Changes in IGFBP-2 and -4 levels are also due to changes in intrafollicular levels of specific proteases. Recently, we have shown that the pregnancy-associated plasma protein-A (PAPP-A) is responsible for the degradation of IGFBP-4 in preovulatory follicles of domestic animals. Expression of PAPP-A mRNA is restricted to the granulosa cell compartment, and is positively correlated to expression of aromatase and LH receptor. From recent evidence, the bone morphogenetic protein (BMP) family would also play a key role in ovarian physiology of domestic animals. In particular, we and others have recently shown that a non-conservative substitution (Q249R) in the bone morphogenetic protein-receptor type IB (BMPR-IB) coding sequence is fully associated with the hyperprolific phenotype of FecB(B)/FecB(B) Booroola ewes. BMP-4 and GDF-5, natural ligands of BMPR-IB, strongly inhibit secretion of progesterone by ovine granulosa cells in vitro, but granulosa cells from FecB(B)/FecB(B) ewes are less responsive than those from FecB(+)/FecB(+) to the action of these peptides. It is suggested that in FecB(B)/FecB(B) ewes, Q249R substitution would impair the function of BMPR-IB, leading to a precocious differentiation of granulosa cells and of follicular maturation. Interestingly, recent findings have described mutations in BMP-15 gene associated with hyperprolific phenotypes in Inverdale and Hanna ewes, suggesting that the BMP pathway plays a crucial role in the control of ovulation rate.     

The Sertoli cell nucleolus in domestic and wild animals

Sertoli cells produce special microenvironment for developing germ cells; therefore it is assumed that they play primary role in the onset and control of spermatogenesis. In this connection we extended our previous study on the ultrastructure of Sertoli cells in different domestic and wild animals with special regard to nucleolus. Sertoli cells of domestic and wild ruminants possess the typical vesicular nucleolus except for fallow deer, in this species no vesicular nucleolus occurs in Sertoli cells even during the rut. In roe.buck, another wild ruminant with seasonal spermatogenesis, cyclic changes were found in the nucleolus of Sertoli cells. If no spermatogenesis is present, the Sertoli cells have a reticular nucleolus. Membranous vesicles appear in the nucleolus of Sertoli cells of roe-buck at the onset of spermatogenesis 1-2 months before rut. In domestic ruminants with continuous spermatogenesis the vesicular nucleolus in Sertoli cells is present permanently. During postnatal development of bull and ram the vesicular nucleolus appears in Sertoli cells just before the onset of spermatogenesis. In experimental cryptorchidism of bulls a vesicular nucleolus is found in the Sertoli cells. Our observations and experiments support a hypothesis that Sertoli cells have primary role at the onset and the maintenance of spermatogenesis.     

The ovarian insulin and insulin-like growth factor system with an emphasis on domestic animals

Insulin and insulin-like growth factors (IGFs) have direct effects on cultured ovarian cells. These effects include stimulation of granulosa cell mitogenesis, granulosa and luteal cell progesterone production, and thecal cell androgen production and appear similar among species. However, species differences exist with regard to insulin and IGF-I effects on granulosa cell estradiol production. In addition to endocrine effects of insulin and IGFs, IGFs are produced by granulosa, thecal, and luteal cells, allowing for an intraovarian autocrine and paracrine system. Granulosa, thecal, and luteal cells contain receptors for insulin and IGFs, and these receptors appear to mediate the effects of insulin and IGFs. Adding to the complexity of the regulatory role of IGFs is the presence of IGF-binding proteins (IGFBPs) within the ovary. These IGFBPs are produced by granulosa, thecal, and luteal cells, and their production is hormonally regulated. Evidence for a coherent mechanism by which insulin, IGFs, and IGFBPs interact and regulate ovarian function in vivo has yet to be found.