一组技术研究动态

1酵母可稳定应激状态下动物消化道内的微生物菌群拉曼动物营养公司（Lallemand Animal Nutrition）的N.Walker、M.Cintora、H.Durand和Y.le Treut证实,活性酵母产品对包括反刍动物和单胃动物在内的繁殖期畜产动物的健康和生产性能有重要的作用。     

Evaluation of hemostatic derangements associated with canine anaphylaxis and the relationship to syndrome severity

Objective

To describe hemostatic derangements associated with canine anaphylaxis and to assess for association with syndrome severity.

Design

Prospective observational study.

Setting

University teaching hospital.

Animals

Twenty-seven client-owned dogs, recruited from November 2018 to January 2022, diagnosed with anaphylaxis of varying severity were included. Study inclusion required presentation <6 hours after initiation of clinical signs, no medications or history of illness within the prior 2 weeks, lack of comorbidities expected to affect hemostasis, and lack of a disease state that could alternatively explain the clinical presentation.

Interventions

Blood samples were collected within the first hour of presentation for CBC, serum biochemistry, prothrombin time (PT), activated partial thromboplastin time (aPTT), and viscoelastic coagulation testing for use with a cartridge-based point-of-care device.

Measurements and main results

Clotting time and clot formation time were prolonged, alpha angle and maximum clot firmness were decreased, PT and aPTT were prolonged, and platelet counts were lower in severe cases compared to mild and moderate cases. There were no differences for any parameter between mild and moderate cases. The presence or absence of abdominal effusion was not associated with hemostatic status.

Conclusions

Global hemostatic derangements consistent with hypocoagulability are a prominent feature of severe anaphylaxis in dogs and should be considered for routine evaluation.     

病毒感染与肠道菌群关系的研究进展

人和动物的肠道内定植着数量众多的微生物,它们对宿主正常生理功能至关重要。肠道菌群与宿主不断地进行相互作用,形成互利共生的关系,影响机体健康。病毒感染会通过影响肠道菌群进而影响机体的免疫和代谢功能。肠道菌群或益生菌也会影响病毒的感染和疫苗的免疫效果。了解病毒与肠道菌群或益生菌的相互作用及肠道菌群对疫苗免疫效果的影响,有助于揭示疾病的发病机制,通过调控肠道菌群来治疗疾病。现主要从病毒与肠道菌群的相互作用,益生菌对病毒感染的影响和肠道菌群对疫苗免疫效果的影响三方面进行综述。     

Eosinophil and IgA responses in sheep infected with Teladorsagia circumcincta

Infections of sheep with the gastrointestinal nematode Teladorsagia circumcincta are characterised by increased concentrations of IgA, eosinophilia and mastocytosis but the interactions between these immune responses are unclear. We investigated the kinetics of the parasite-specific IgA and eosinophil responses in controlled infections in lambs to determine if there were any associations with subsequent worm growth and survival. IgA and eosinophil responses had very similar kinetics and variation in both responses accounted for more of the variation in adult worm length than either trait alone suggesting that IgA and eosinophils interact in regulating the growth of T. circumcincta. Curiously, those animals with higher peak eosinophil responses had longer worms at slaughter emphasising the intriguing complexity of the immune responses to these parasitic infections.     

旋毛虫各隔离种嗜酸性粒细胞变化的研究

旋毛虫各隔离种感染猪后,其血液中嗜酸性粒细胞显著增多,而其它各类细胞无明显变化,嗜酸性粒细胞于感染后７ｄ开始升高,１６ｄ左右达最高峰,以后逐渐下降趋势;猪旋毛虫和旋毛形线虫的嗜酸性粒细胞数量始终高于犬旋毛虫和本地毛形线虫,嗜酸性粒细胞增多可作为早期诊断旋毛虫病的重要临床指标之一。     

Ascaris suum Infection in Calves II. Circulating and Marrow Eosinophil Responses

An increment in the number of circulating eosinophils occurred between the 11th and 14th days after infection with Ascaris suum and this increase was generally greater after a challenge infection. Continual infection with small numbers of A. suum eggs over prolonged periods resulted in circulating eosinophil levels which fluctuated and were dose-dependent. The per cent marrow eosinophils always increased after a primary infection and a greater increase usually followed a challenge infection. The maximum increment of marrow eosinophils occurred between the tenth and 12th days and preceded the rise in circulating eosinophils by 36 hours. Antihistamine therapy did not alter eosinophil responses to A. suum. Circulating eosinophilia was not usually reflected by drastic changes in differential white cell counts. However, an increase in total white cell count often followed infection with A. suum and frequently parallelled changes in eosinophil counts. Hemoglobin and P.C.V. values remained within normal limits in A. summ infected calves.     

Altered response to hydrogen sulphide during experimental colitis in rats

Hydrogen sulphide (H₂S) is produced in the intestine by sulphate‐reducing bacteria and during metabolism of L‐cysteine within the mucosa. This gasotransmitter induces anion secretion by stimulating enteric neurons and by a direct effect on epithelial cells. As H₂S is discussed to exert both pro‐ and anti‐inflammatory actions, we aimed to investigate the role of H₂S during experimental colitis by comparing the effects of blockade of H₂S‐forming endogenous enzymes with the effect of a S‐reduced diet to diminish microbial production of H₂S. Rectal application of trinitrobenzenesulfonic acid (TNBS) was used to induce chronic colitis. The level of inflammation was assessed macroscopically and histologically. In Ussing chamber experiments, colonic specimens from TNBS‐treated animals exhibited a higher tissue conductance, that is, a higher epithelial permeability, and a slightly reduced basal short‐circuit current (a measure of net ion transport) in relation to non‐inflamed control tissue. Analgetic treatment with flupirtine, a central antinociceptive analgetic, did not interfere with the induction of the inflammatory response so that all animals were treated with flupirtine to reduce pain and distress during the development of colitis. The secretory response evoked by an exogenous H₂S donor, NaHS, was significantly decreased after induction of colitis, whereas the response to Ca²⁺‐ or cAMP‐dependent secretagogues was unaltered. This downregulation was not observed in the colitis group fed on a S‐reduced diet. The decreased NaHS response indicates a desensitization of the tissue by inflammation, which might be explained by an upregulation of colonic H₂S production as described in some models of inflammation.     

Changes in immunoglobulin levels in whey during experimental Streptococcus agalactiae mastitis

Total protein and immunoglobulin levels in the wheys of eight first lactation heifers, four vaccinated and four unvaccinated, were measured during three consecutive experimental intramammary infections with Streptococcus agalactiae. There were no significant differences between infections 1, 2 and 3 in the protein or immunoglobulin content of the uninfected quarters. Peak whey total protein of the infected quarters came earlier with each infection, until by the third they were seen after eight hours. During this acute phase a reversal of the normal milk IgG1/IgG2 ratio in all infected quarters was measured. Increases in whey IgA and IgM in the infected quarters of the vaccinates were also noted. A similar response only occurred following the third infection of the unvaccinated animals. All whey immunoglobulin levels returned to normal by 48 hours after infection, after which only IgG1 levels increased in infected quarters.     

Supplementation of a lacto-fermented rapeseed-seaweed blend promotes gut microbial-and gut immune-modulation in weaner piglets

Background:The direct use of medical zinc oxide in feed will be abandoned after 2022 in Europe,leaving an urgent need for substitutes to prevent post-weaning disorders.Results:This study investigated the effect of using rapeseed-seaweed blend(rapeseed meal added two brown macroalgae species Ascophylum nodosum and Saccharina latissima)fermented by lactobacilli(FRS)as feed ingredients in piglet weaning.From d 28 of life to d 85,the piglets were fed one of three different feeding regimens(n=230 each)with inclusion of 0%,2.5% and 5% FRS.In this period,no significant difference of piglet performance was found among the three groups.From a subset of piglets(n=10 from each treatment),blood samples for hematology,biochemistry and immunoglobulin analysis,colon digesta for microbiome analysis,and jejunum and colon tissues for histopathological analyses were collected.The piglets fed with 2.5% FRS manifested alleviated intraepithelial and stromal lymphocytes infiltration in the gut,enhanced colon mucosa barrier relative to the 0% FRS group.The colon microbiota composition was determined using V3 and V1-V8 region 16S rRNA gene amplicon sequencing by Illumina NextSeq and Oxford Nanopore MinION,respectively.The two amplicon sequencing strategies showed high consistency between the detected bacteria.Both sequencing strategies indicated that inclusion of FRS reshaped the colon microbiome of weaned piglets with increased Shannon diversity.Prevotella stercorea was verified by both methods to be more abundant in the piglets supplied with FRS feed,and its abundance was positively correlated with colonic mucosa thickness but negatively correlated with blood concentrations of leucocytes and IgG.Conclusions:FRS supplementation relieved the gut lymphocyte infiltration of the weaned piglets,improved the colon mucosa barrier with altered microbiota composition.Increasing the dietary inclusion of FRS from 2.5% to 5% did not lead to further improvements.     

Post-weaning feed intake level modulates gut morphology but not gut permeability in weaned piglets

Piglets with a high voluntary feed intake were compared with piglets fed restrictedly. Weaning induced changes in gut morphology and permeability. The intake level of dry pelleted feed affected intestinal villous architecture but did not affect permeability to small or large molecules from d0 to d7 post-weaning. A restricted feed intake level negatively affected gut morphology at d4 post-weaning. This effect could be alleviated but not completely prevented by a high voluntary intake of dry pelleted feed directly after weaning.