Sows intramammarily inoculated with Escherichia coli at parturition. II. Effects on the densities of MHC class II(+), CD4(+) and CD8(+) cells in the mammary gland

The aim of this study was to determine the density of MHC class II, CD4 and CD8 positive cells in mammary glands of sows around parturition, and whether the densities were altered following intramammary inoculation with Escherichia coli prior to parturition. Also, animals developing clinical disease after inoculation were compared with animals not developing clinical disease. Fourteen cross-bred primiparous sows were subject to intramammary inoculation with E. coli bacteria 24h before estimated parturition. Mammary gland biopsies were collected and clinical observations were made. Four sows were categorised as clinically ill based on general condition, body temperature and gross mammary affection. There were no changes in density of MHC class II, CD4 and CD8 positive cells in non-inoculated glands around parturition, while significant changes in densities were shown in inoculated glands. Here, the density of MHC class II, CD4 and CD8 positive cells reached a peak at 72 h post-inoculation (p<0.01). In sows developing clinical disease, there was a tendency to an over all lower density (p=0.07) of MHC class II positive cells in inoculated glands compared with sows not developing clinical disease. When comparing the categories with respect to the density of CD4 and CD8 positive cells, the sows developing clinical disease showed a higher density (p=0.03) of CD4 and CD8 positive cells in inoculated glands than sows not developing disease. No differences were shown between categories in non-inoculated glands. It is concluded that the density of MHC class II, CD4 and CD8 positive cells seems to be unaltered around parturition. However, there is a rapid increase in density of these cells following intramammary inoculation with E. coli. Also, the data suggest that there is a difference between sows developing and sows not developing clinical disease after inoculation with respect to the increase in density of MHC class II, CD4 and CD8 positive cells in the mammary gland.     

Lymphocyte subsets in the mammary gland of sows

The presence and localisation of lymphocyte subsets together with class II bearing cells in the mammary gland of sows, were studied at different periods of the reproductive cycle by immunohistochemistry and compared with blood. All cell types involved in the immune response were present in the mammary gland at the different stages of gestation and lactation and nearer the alveolar epithelium as gestation proceeded: T lymphocytes, including CD4+ and CD8+, B lymphocytes and class II bearing cells (epithelial cells and macrophages). The results indicated an early accumulation of T lymphocytes, specifically T helper cells, during pregnancy; the specific increase of IgA lymphocytes occurring after this phase could suggest a role for these T cells in the induction of IgA response. The local accumulation of immune cells sustains the view that the mammary gland is able to mount a true local immune response and the increase in CD8+ cells near the epithelium suggests a role in local immune defence.     

Local immunity in the mammary gland.

The mammary glands of pregnant and non-pregnant sheep were stimulated by infusion of killed Staphylococcus aureus, and the lymphoid cell response delineated with a panel of monoclonal antibodies. Seven days after antigen infusion, the mammary glands of both pregnant and non-pregnant sheep displayed a striking feature, characterised by the presence of numerous CD45R+ MHC class II+ B cells in the periductal connective tissues. These cells were seen to be clustering around blood capillaries with very prominent endothelial cell lining. Some CD5+ CD4+ lymphocytes were scattered among the B-cell clusters, whereas a few CD8+ lymphocytes were seen mainly at the periphery of the B-cell clusters. Fourteen days after antigen infusion, numerous plasma cells were observed, most of them being of the IgA isotype. Seven days after parturition (approximately 40 days after antigen infusion) the number of lymphocytes and plasma cells in the infused glands had declined dramatically. These data indicate that B cell and helper T-cell interaction can take place at the local sites of antigen stimulation in the mammary gland.     

Influence of age and parity on the distribution of cells expressing major histocompatibility complex class II, CD4, or CD8 molecules in the endometrium of mares during estrus

OBJECTIVE: To evaluate effect of age and parity on distribution and number of cells expressing major histocompatibility complex (MHC) class II, CD4, or CD8 molecules in the endometrium of mares during estrus. ANIMALS: 32 gynecologically healthy mares, categorized as young (3 to 8 years; n = 17) or old (9 to 16 years; 15) and nulliparous (n = 6), nulliparous embryo donors (16), or parous (10). PROCEDURES: Endometrial specimens collected from the uterine body and horns during estrus were stained by use of the avidin-biotin-peroxidase method, using monoclonal antibodies against equine MHC class II, CD4, and CD8 molecules. Labeled cells in the stratum compactum within 5 randomly selected fields at 400x magnification (total area = 0.31 mm2) were counted, and numbers were compared among groups and between locations. RESULTS: Age did not affect cell numbers within the 3 cell subsets examined. Numbers in each subset were higher in the uterine body than in the horns, although the difference was not significant for cells expressing MHC class II. Significantly more cells expressing MHC class II molecules were detected in the uterine body of nulliparous and parous mares than in embryo donors, whereas in the horns, these cells were significantly higher in number only in parous mares. Parity did not affect number of CD4+ or CD8+ cells. CONCLUSIONS AND CLINICAL RELEVANCE: The increased likelihood for endometritis to develop in mares as they age cannot be explained by a decrease in number of cells expressing MHC class II, CD4, or CD8 molecules within the endometrium. However, greater number of cells within these 3 subsets detected in the uterine body, compared with the horns, during estrus suggests a local readiness to act against microorganisms or semen introduced during mating or insemination.     

Expression of adhesion molecules on milk and blood lymphocytes from periparturient dairy cattle with Johne's disease

Twelve dairy cows infected with Mycobacterium avium subsp. paratuberculosis were monitored for lymphocyte subsets and expression of adhesion molecules on cells in blood and milk at parturition and at intervals up to 21 days post-partum. Using fluorescent antibody labeling of cells and analysis by flow cytometry, we determined percentages of T cell subsets (CD4+, CD8+, gammadelta+) and expression of adhesion molecules (CD62L, LFA-1, LPAM-1, and CD44) on cells from blood and milk of these cows. Significantly higher percentages of CD8+ cells were found in milk than in blood at all time points; there were no significant differences in percentages of CD4+ or gammadelta+ cells. CD62L, LFA-1, and LPAM-1 were expressed on a significantly higher percentage of all T cell subsets in milk than in blood at various times after parturition. No differences were seen in expression of CD44. Increased percentages of T lymphocytes expressing adhesion molecules in milk compared to blood suggest that a migratory population of cells is being selectively recruited to the mammary gland from the circulation.     

Influence of post-ovulatory insemination on sperm distribution,pregnancy and the infiltration by cells of the immune system,and the distribution of CD2, CD4, CD8 and MHC class II expressing cells in the sow endometrium

This study investigates the distribution of leucocytes, CD2+, CD4+, CD8+ lymphocyte subpopulations and MHC class II expressing cells in the sow endometrium following post-ovulatory insemination in relation to clinical findings and pregnancy outcome. Crossbred multiparous sows were inseminated once either at 15-20 h after ovulation [experiment 1, slaughtered at 20-25 h (5-6 h after artificial insemination (AI), group 1-A, n = 4), at 70 h after ovulation (group 1-B, n = 4), on day 11 (group 1-C, n = 4, first day of standing oestrus = day 1) or on day 19 (group 1-D, n = 4)] or 30 h after ovulation [experiment 2, slaughtered at 5-6 h after AI (group 2-A, n = 4) or on day 19 (group 2-D, n = 3)]. The uterine horns were flushed to control for the presence of spermatozoa and neutrophils and/or for recovery of oocytes and/or embryos. Mesometrial uterine samples were plastic embedded and stained. Cryofixed uterine samples were analysed by immunohistochemistry using mAbs to lymphocyte subpopulations and MHC class II molecules. Light microscopy was used to examine surface (SE) and glandular epithelia (GE), and connective tissue layers, both subepithelially (SL) and glandular (GL). In experiment 1, group 1-A, only one sow had spermatozoa in the utero-tubal junction (UTJ). Marked/moderated numbers of neutrophils and spermatozoa were observed in the flushings of two sows. In group 1-B, altogether 23 of 48 oocytes were cleaved. Day 11 (1-C), embryos with small diameter were observed. Day 19 (1-D), no embryos were found but small pieces of foetal membrane were observed in one of the sows. In group 1-A, large numbers of neutrophils were found within the SE and SL but with high individual variation. For T lymphocyte subpopulations, in the SE, most CD2+ cells were found in group 1-A. For both SE and GE in all groups, the number of CD8+ cells was significantly larger than that of CD4+ cells. In experiment 2, group 2-A, no sow had spermatozoa in the UTJ or in the uterine flushings. At day 19, no sow was pregnant. In group 2-A, large numbers of neutrophils were found within the SE and SL but with high individual variation. At day 19, high E2 levels showed a hormonal prooestrous stage but the endometrial neutrophil infiltration normally expected at pro-oestrus was absent. In conclusion, post-ovulatory insemination (about 18 h after ovulation) resulted in impaired spermatozoa transport within the uterus and embryonic degeneration. In sows post-ovulatory inseminated at a later stage (30 h after ovulation), no sow was pregnant. In both experiments, disturbed immune cell patterns were observed in some individuals.     

Quantification of mammary gland tissue size and composition changes after weaning in sows

The objectives of this study were to characterize the tissue compositional changes in porcine mammary glands after weaning and to determine whether administration of estradiol alters the profile of these tissue changes. Forty-five primiparous sows were assigned randomly to one of two treatment groups after weaning, control or estrogen treated. Estrogen-treated sows received twice-daily injections of estradiol-17beta (0.125 mg/kg of BW); control sows received vehicle injections. Sows were weaned at d 21 of lactation and killed on either d 0 (d of weaning; n = 5) or on d 2, 3, 4, 5, or 7 after weaning (n = 4 per treatment on each day). Teat order relative to suckling behavior was observed on the day before weaning to determine which mammary glands the piglets suckled. Suckled and non-suckled glands were identified from the teat order observation, and individual mammary glands were collected at slaughter. Mammary glands were trimmed of skin and extraneous fat pad, individually weighed, and bisected to measure cross-sectional area. The remaining half of each gland was ground and stored at -20 degrees C for chemical analyses. Frozen tissue was used for measuring tissue DNA, DM, protein, fat, and ash contents. Suckled mammary glands of sows undergo significant and dramatic changes during the initial 7 d after weaning, with significant changes occurring even by d 2 after weaning. Mean cross-sectional area of parenchymal tissue in suckled mammary glands decreased from 59.7 +/- 2.1 cm2 on the day of weaning to 26.8 +/- 2.3 cm2 by d 7 after weaning (P < 0.0001). Mammary gland wet weight decreased from 485.9 +/- 22.0 g on the day of weaning to 151.5 +/- 24.8 g by d 7 after weaning (P < 0.0001), whereas DNA decreased from 838.8 +/- 46.2 g on the day of weaning to 278.4 +/- 52.5 g by d 7 after weaning (P < 0.0001). The changes in gland wet weight and DNA during the period of mammary gland involution in the sow represent loses of over two-thirds of the parenchymal mass and nearly two-thirds of the cells that were present on the day of weaning. Estrogen treatment did not affect overall mammary involution during the first 7 d after weaning. Mammary glands that were not suckled during lactation had no further loss of parenchymal tissue during the first 7 d after weaning. Mammary gland involution in the sow is a rapid process and is probably irreversible within 2 or 3 d after weaning.     

C-reactive protein in monitoring and evaluation of effects of therapy of the MMA syndrome of sows

The elevated concentration of CRP in sows at the early stage of the MMA reflected the inflammation in the reproductive tract and in the mammary gland. Monitoring the level of CRP during the first days after parturition may be used to diagnose early stages of the MMA and to start therapy. In the treated MMA sows the level of CRP steadily decreased, and by the end of the experiment it had returned to the normal level. In the non-treated MMA sows CRP persisted at a high level and at day 10 of the experiment it was 13 times higher than in the treated animals and 16 times higher than in controls. Measurements of serum CRP are valuable in monitoring the health status of sows after parturition and should be introduced as the diagnostic method of the MMA syndrome in sows. The determination of the concentration of serum CRP during the first two days after parturition should be used for diagnosis of the early stages of MMA syndrome in sows and to start therapy when clinical symptoms of MMA are still absent.     

Sows intramammarily inoculated with Escherichia coli influence of time of infection, hormone concentrations and leucocyte numbers on development of disease

The aim of this study was to identify factors that influence the development of disease in sows inoculated with Escherichia coli in the mammary gland. Ten cross-bred primiparous sows were intramammarily inoculated with living E. coli bacteria at different time points before parturition: seven sows within 48 h before parturition and three sows approximately 96 h before parturition. Before and after inoculation, blood samples and mammary gland biopsy specimens were collected and clinical observations were made. All seven sows inoculated close to parturition developed a rectal temperature of >39.5 degrees C during the first 48 h post-partum and two of them also showed other signs of clinical disease. In the sows inoculated 4 days before parturition, the rectal temperature never exceeded 39.5 degrees C during the first 48 h post-partum and none of them showed any other sign of clinical discase. There was a tendency (P < 0.1) that histological signs of mastitis were more frequent in the sows inoculated close to parturition. There were no overall differences between the two groups of sows in plasma concentrations of cortisol, oestradiol-17beta and 15-ketodihydro-PGF2alpha before inoculation. Before inoculation, the number of neutrophils in the blood was overall higher (P < 0.05) in the group of sows that were inoculated close to parturition. In comparison, the number of lymphocytes before inoculation had a tendency (P < 0.1) to be lower in that group. The data suggest that the time of infection of the mammary gland relative to parturition and the number of circulating neutrophils at the time of infection influence the development of chinical coliform mastitis in the sow.     

Sows intramammarily inoculated with Escherichia coli at parturition: I. Functional capacity of granulocytes in sows affected or non-affected by clinical mastitis

The objective of this study was to investigate if occurrence of clinical disease was related to granulocyte traits in sows. Functional capacity of granulocytes and plasma steroid hormone concentrations were assessed before inoculation with Escherichia coli in the mammary glands in sows at parturition. Blood samples were taken for 3 days approximately 1 week before parturition, and granulocyte migration, phagocytic capacity and expression of CD 18 adhesion molecules were determined. Inoculation was done within 36 h before partus. Thereafter, daily thorough clinical examinations were performed including udder health, habitus, appetite and rectal temperature, to assess the severity of disease. Based on the clinical findings four sows were classified as affected and eight as non-affected by clinical mastitis within 48 h after parturition.No difference (p>0.10) in pre-inoculation chemotaxis, phagocytosis or CD 18 expression was found between granulocytes from the sows resisting and developing clinical mastitis, respectively. However, there was an effect by the individual sow (p=0.001) on the numbers of granulocytes and white blood cells, and on plasma concentrations of estradiol-17beta and progesterone. In conclusion, these data does not suggest that impaired chemotaxis or phagocytosis by blood granulocytes contribute to the development of clinical coliform mastitis in the periparturient sow.     

Escherichia coli inoculation of porcine mammary glands affects local mRNA expression of Toll-like receptors and regulatory cytokines

The expression of mRNAs for the Toll-like receptors (TLRs) TLR2 and TLR4, pro- and anti inflammatory cytokines and their receptors was evaluated in mammary gland biopsy material collected from sows intramammarily inoculated with Escherichia coli strain O127 at parturition. Quantitative real-time RT-PCR analysis showed increased mRNA levels for TLR2, the proinflammatory cytokines interleukin IL-1beta and tumor necrosis factor-alpha TNF-alpha, and the anti-inflammatory cytokine IL-10 in the inoculated mammary glands 24h after inoculation. Increased mRNA levels of the proinflammatory cytokine IL-6 were only observed in the inoculated mammary glands of sows that developed clinical signs of mastitis. In contrast, the expression of the anti-inflammatory cytokine, transforming growth factor-beta 1 (TGF-beta1) mRNA was unaltered, as was mRNA expression for the IL-1 receptor type I (IL-1R1). Furthermore, IL-1beta and IL-10 mRNA expression was higher in the inoculated mammary glands of sows that developed clinical signs of mastitis compared with sows that remained clinically healthy. Notably, sows that developed clinical signs of mastitis had significantly lower pre-inoculation levels of IL-1beta mRNA than sows that remained clinically healthy. These findings suggest that development of coliform mastitis is associated with the level of local expression of regulatory cytokines in response to intramammary E. coli inoculation and infection.     

Effects of breeding at the second oestrus or after post-weaning hormonal treatment with altrenogest on subsequent reproductive performance of primiparous sows

This study investigated the effects of breeding at the second oestrus after weaning or after feeding an orally active progestagen (altrenogest) on the subsequent reproductive performance of primiparous sows. After 3 weeks of lactation, 663 weaned sows of two genotypes were allocated into three groups: G1--breeding at the first oestrus after weaning; G2--breeding at the second oestrus after weaning and G3--treatment with altrenogest for 5 days after weaning and breeding at the first oestrus after the end of the treatment. Body weight at breeding was lower in G1 and G3 than in G2 sows (p < 0.05). The interval to show oestrus was similar for G1 and G2 groups (p > 0.05) but higher (p < 0.05) than that observed in G3 group. Within genotype A, percentages of females in oestrus within 10 days were not different (p > 0.05) among groups, whereas in genotype B, more G1 and G2 sows (p < 0.05) showed oestrus than G3 sows. In both genotypes, lower farrowing rates were observed in G3 than in G1 and G2 sows (p < 0.05) and a greater litter size (p < 0.05) was observed in G2 sows. In genotype A, the number of total born piglets was similar for G1 and G3 groups (p > 0.05), whereas in genotype B, G1 sows had a greater litter size than G3 sows (p < 0.05). Body weight at weaning and at breeding was similar (p > 0.05) between farrowed and non-farrowed sows in all groups. Reproductive performance is not improved in primiparous sows treated with altrenogest during 5 days after weaning. The reproductive performance of genotype B sows is compromised in Control and Altrenogest-treated sows but not in those bred at the second oestrus after mating. Breeding at the second oestrus after weaning allows primiparous sows to gain weight between weaning and service, and increases their farrowing rate and subsequent litter size.     

Effects of salinomycin on sow weight change during lactation and on sow reproductive performance

Forty-five gravid cross-bred sows (mean parity 3.3 +/- .3) were randomly allotted to two dietary treatments: corn-soybean mean (CS) or CS plus 60 mg salinomycin per kilogram of diet (CSS). Sows were fed their respective diets through two successive parities with dietary treatment initiated at 100 d postcoitum and continued until weaning of the second successive litter. Therefore, sows fed CSS received salinomycin for 14 d before the first parturition and for approximately 153 d before the second parturition. Daily feed intake was restricted to 2 kg.hd-1.d-1 during gestation and to 3 kg.hd-1.d-1 from weaning to breeding. All sows. had ad libitum access to feed during lactation. Sows were weighed 7 d prior to parturition, at weaning and at breeding. Weaning-to-estrus interval and farrowing interval were recorded for all sows. Litters were weighed at birth and weaning. There were no differences (P greater than .05) between dietary treatments in sow weights before parturition, at weaning or at breeding for either first or second farrowing. The CSS-fed sows lost more weight from weaning to breeding after the first (P less than .03) and second (P less than .05) lactation periods than CS-fed sows. The CSS-fed sows tended to gain more (P = .06) weight during lactation than CS-fed sows. There were no differences (P greater than .05) between treatments in lactation feed intake, weaning-to-estrus interval, farrowing interval, litter size born or weaned, litter weights at birth or at weaning, or in sow culling rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lymphocytes and T lymphocyte subsets are regionally distributed in the female goat reproductive tract: influence of the stage of the oestrous cycle

The reproductive tract of the female is a part of the mucosal system which protects from pathogens invasion. We have analysed the presence and distribution of total lymphocytes, plasma cells (antibody secreting B cells) and T lymphocytes subsets in the reproductive tract of the female goat. The influence of the oestrous cycle on the densities of lymphocytes and plasma cells of the cervix and uterus horn was evaluated in sections prepared for conventional histology. Immunocytochemistry was used for the study of lymphocyte subsets by confocal microscopy and immunoperoxidase techniques. Present results show that the reproductive tract of the goat is a site rich in lymphocytes. These cells were found mingled with the epithelial cells of the endometrium and distributed throughout the stroma. Lymphocyte aggregates were observed in the stroma. Lymphocyte but not plasma cell number changed depending on the reproductive stage of the goats. The impact of the hormonal environment was different for the cervix and uterine horn. Immunocytochemistry studies evidenced the presence of cells displaying immunoreactivity for both CD 4+ and CD 8+ antibodies in the epithelial layer and stroma of the cervix and uterine horn. These cells were more numerous in the cervix and were also found infiltrating the luminal epithelia of endometrial glands. Overall, our results indicate that lymphocyte distribution is different in the cervix and the horn, and is influenced by the stage of the reproductive cycle. In summary, CD 4+ and CD 8+ T lymphocytes subsets could be found in the endometrium of both the cervix and uterine horn of the goat reproductive tract.     

Sows Intramammarily Inoculated with Escherichia coli: Influence of Time of Infection,Hormone Concentrations and Leucocyte Numbers on Development of Disease

The aim of this study was to identify factors that influence the development of disease in sows inoculated with Escherichia coli in the mammary gland. Ten cross‐bred primiparous sows were intramammarily inoculated with living E. coli bacteria at different time points before parturition: seven sows within 48 h before parturition and three sows approximately 96 h before parturition. Before and after inoculation, blood samples and mammary gland biopsy specimens were collected and clinical observations were made. All seven sows inoculated close to parturition developed a rectal temperature of >39.5°C during the first 48 h post‐partum and two of them also showed other signs of clinical disease. In the sows inoculated 4 days before parturition, the rectal temperature never exceeded 39.5°C during the first 48 h post‐partum and none of them showed any other sign of clinical disease. There was a tendency (P < 0.1) that histological signs of mastitis were more frequent in the sows inoculated close to parturition. There were no overall differences between the two groups of sows in plasma concentrations of cortisol, oestradiol‐17β and 15‐ketodihydro‐PGF_2α before inoculation. Before inoculation, the number of neutrophils in the blood was overall higher (P < 0.05) in the group of sows that were inoculated close to parturition. In comparison, the number of lymphocytes before inoculation had a tendency (P < 0.1) to be lower in that group. The data suggest that the time of infection of the mammary gland relative to parturition and the number of circulating neutrophils at the time of infection influence the development of clinical coliform mastitis in the sow.     

The Endometrium of the Anoestrous Female Pig: Studies on Infiltration by Cells of the Immune System

The aim of this study was to investigate the distribution of immune cells in the endometrium of anoestrous female pigs, five sows in anoestrus by lactation and five pre-pubertal gilts (Swedish Landrace x Swedish Yorkshire). Uterine samples, taken immediately after slaughter, were fixed, embedded in plastic resin and stained with toluidine blue or cryo fixed and stored in a freezer at -70 degrees C until analysed by immunohistochemistry with an avidin-biotin peroxidase method. Immune cells in the surface (luminal) and the glandular epithelium as well as the subepithelial and the glandular connective tissue layers were counted using light microscopy. In the surface (luminal) and the glandular epithelia of gilts and sows, lymphocytes were the predominant immune cells found. There were no significant differences between gilts and sows. Macrophages were detected in the glandular epithelium of sows but not in gilts. In the subepithelial and the glandular connective tissue layers of both gilts and sows, lymphocytes were also the most common immune cells found. The numbers of lymphocytes and macrophages were significantly higher in the sows than in the gilts (p 相似文献   

Morphometric analysis of proinflammatory cytokines in mammary glands of sows suggests an association between clinical mastitis and local production of IL-1beta, IL-6 and TNF-alpha

Twelve healthy primiparous sows received intramammary inoculation with Escherichia coli (serotype O127) during the 24-h period preceding parturition. Mammary gland biopsy samples were taken immediately before inoculation (0 h) and from the inoculated and the contralateral non-inoculated glands 24 h after inoculation. The analyses of interleukin-1 beta (IL-1beta), IL-6, IL-8, and tumor necrosis factor alpha (TNF-alpha) by immunohistochemistry revealed that the production of these proinflammatory cytokines significantly increased in the inoculated mammary glands of sows that developed clinical signs of mastitis (affected group, n=4) 24 h after inoculation. This was also true for IL-8 in the inoculated mammary glands of sows that did not develop clinical signs of mastitis (nonaffected group, n=8). Sows that developed clinical signs of mastitis displayed significantly lower constitutive production of IL-1beta than did sows that remained clinically healthy. The data indicate that the development of clinical symptoms of coliform mastitis in the sow is associated with a locally increased proinflammatory cytokine production in response to intramammary E. coli infection.     

宫内生长迟缓仔猪T细胞的发育研究

研究旨在探讨从出生到断奶不同日龄宫内生长迟缓(IUGR)猪T细胞的发育变化情况。选用体重相近和配种期相同的达兰初产妊娠母猪30头,分娩时从每窝仔猪中挑选1头正常体重猪和1头IUGR猪,分别在1、7、14、21、28日龄时屠宰取胸腺,分离T细胞,通过流式细胞仪测定CD3、CD4、CD8T细胞的数量,每个日龄6个重复。结果表明:出生后第1天IUGR仔猪与正常仔猪的CD4+CD8+细胞(双阳性T细胞)占总T细胞的百分比差异显著(P<0.05);出生后第7天IUGR仔猪与正常仔猪的CD4细胞占总T细胞的百分比差异极显著(P<0.01);后期各细胞亚群之间没有差异。结果提示,子宫内各种因素的综合影响能造成出生后早期IUGR仔猪T细胞亚群发育不完善,这就从T细胞亚群的发育方面解释了IUGR仔猪免疫力低的原因。     

配种前药物处理对母猪繁殖性能的影响

为了减少人工授精过程中人为操作引入的病原微生物,改善母猪断奶后不发情、延迟发情或发情后配种不受孕所导致的母猪繁殖性能降低的现象,在饲养管理良好、免疫程序健全的条件下,试验采用在母猪配种前对其进行药物处理。将试验母猪随机分为2组,A组为断奶经产母猪(n=65),B组为第2情期后的后备母猪(n=58)。将A组进一步分为A-Ⅰ组(n=36,投药组)和A-Ⅱ组(n=29,空白对照组),B组进一步分为B-Ⅰ组(n=34,投药组)和B-Ⅱ组(n=24,空白对照组)。统计发情率、受胎率、分娩率及产仔数等繁殖指标。结果表明:A-Ⅰ组每头母猪断奶10 d内发情率为100%,与A-Ⅱ组发情率(96.55%)相比差异不显著(P>0.05);A-Ⅰ组情期受胎率为91.67%,分娩率为86.11%,产仔数为11.32头,而A-Ⅱ组情期受胎率为85.71%,分娩率为78.57%,产仔数为9.95头,差异均显著(P<0.05);B组内,除健仔数外其余各指标差异均不显著(P>0.05)。说明在配种前给经产母猪投药,可以改善母猪繁殖力。