Expression Pattern of Vascular Endothelial Growth Factor in Canine Folliculogenesis and its Effect on the Growth and Development of Follicles after Ovarian Organ Culture

In this study, the expressions of VEGF in dog follicles were detected by immunohistochemistry and the effects of VEGF treatment on the primordial to primary follicle transition and on subsequent follicle progression were examined using a dog ovary organ culture system. The frozen‐thawed canine ovarian follicles within slices of ovarian cortical tissue were cultured for 7 and 14 days in presence or absence of VEGF. After culture, the ovaries were fixed, sectioned, stained and counted for morphologic analysis. The results showed that VEGF was expressed in the theca cells of antral follicles and in the granulosa cells nearest the oocyte in preantral follicle but not in granulosa cells of primordial and primary follicles; however, the VEGF protein was expressed in CL. After in vitro culture, VEGF caused a decrease in the number of primordial follicles and concomitant increase in the number of primary follicles that showed growth initiation and reached the secondary and preantral stages of development after 7 and 14 days. Follicular viability was also improved in the presence of VEGF after 7 and 14 days in culture. In conclusion, treatment with VEGF was found to promote the activation of primordial follicle development that could provide an alternative approach to stimulate early follicle development in dogs.     

饲粮高铁对肉仔鸡十二指肠黏膜铁转运载体基因表达及组织微量元素含量的影响

本试验旨在研究饲粮铁含量对肉仔鸡组织重要微量元素铁、锰、铜、锌含量及十二指肠黏膜主要铁转运载体基因表达的影响,探讨铁对肉仔鸡微量元素吸收和代谢的影响及其机制。将336只1日龄商品代罗斯308肉公雏按照体重随机分成4个组,每组6个重复,每个重复14只鸡。对照组饲喂不额外添加铁的基础饲粮(实测铁含量为78 mg/kg),铁添加组分别饲喂以七水硫酸亚铁(FeSO_4·7H_2O)形式添加100、250或500 mg/kg铁的试验饲粮(实测铁含量分别为166、308和579 mg/kg)。试验期21 d。各组试鸡分别于7、14和21日龄屠宰分析肝脏、心脏、胰腺、十二指肠黏膜和胫骨灰中铁、锰、铜、锌含量及十二指肠黏膜中二价金属转运蛋白(DMT1)和膜铁转运蛋白(FPN1)mRNA表达水平。结果表明:1)500 mg/kg铁添加组1~7日龄和8~14日龄的平均日增重显著低于其他3组(P0.10),250和500 mg/kg铁添加组1~7日龄的平均日采食量显著低于其他2组(P0.10)。2)饲粮铁含量对肉仔鸡7、14、21日龄的血浆总铁结合力以及全血血红蛋白浓度(7日龄除外)和红细胞压积均无显著影响(P0.10),但显著影响7、14和21日龄血浆铁含量和铁饱和度(P0.10),二者均随饲粮铁含量增加而升高。3)7和14日龄心脏及7、14和21日龄肝脏、十二指肠黏膜、胰腺和胫骨灰铁含量均随饲粮铁含量的增加而升高,7、14和21日龄十二指肠黏膜、胰腺和胫骨灰锰含量均随饲粮铁含量的增加而降低;饲粮添加铁显著降低7日龄胰腺锌含量(P0.10),但对其他日龄胰腺和各日龄其他所测组织锌含量以及各日龄所测各组织铜含量均无显著影响(P0.10)。4)饲粮铁含量显著影响7、14和21日龄十二指肠黏膜DMT1和FPN1 mRNA表达水平(P0.10),各日龄DMT1和FPN1mRNA表达水平均随饲粮铁含量的增加而降低。以上结果提示,高铁饲粮可能通过调控十二指肠黏膜DMT1和FPN1基因的表达降低锰和锌在肠道的吸收,进而减少锰和锌在组织中的沉积。     

Comparison of cell populations derived from canine olfactory bulb and olfactory mucosal cultures

OBJECTIVE: To evaluate the numbers and proportions of olfactory ensheathing cells (OECs) in cell cultures derived from the olfactory bulb (OB) and olfactory mucosa of dogs. ANIMALS: 7 dogs. PROCEDURES: OB tissue and olfactory mucosa from the nasal cavity and frontal sinus were obtained from euthanatized dogs and prepared for cell culture. At 7, 14, and 21 days of culture in vitro, numbers and proportions of OECs, astrocytes, and fibroblasts were determined via immunocytochemistry. Antibody against the low-affinity nerve growth factor receptor p75 was used to identify OECs, antibody against glial fibrillary acidic protein was used to identify astrocytes, and antibody against fibronectin was used to identify fibroblasts. RESULTS: Cultured OECs derived from the olfactory mucosa of the nasal cavity and frontal sinus had similar characteristics. However, whereas OECs in the OB cell cultures constituted approximately 50% of the cells at 7 days and approximately 75% at 21 days the proportion of OECs in cultures derived from both mucosal types was much lower, with approximately 40% OECs at 7 days and approximately 25% at 21 days. Analysis of OEC numbers revealed that these changes were accompanied by corresponding decreases and increases in the population of cells with fibronectin receptors. CONCLUSIONS AND CLINICAL RELEVANCE: Although olfactory mucosal cell cultures yielded a sufficient number of OECs for spinal cord transplantation procedures in dogs, modification of culture conditions would be required to ensure that the derived cell population contained a sufficient proportion of OECs.     

Prevention of Ulcer Disease in Goldfish by Means of Vaccination

Abstract

A vaccine comprising cells of Aeromonas bestiarum grown in tryptic soy broth and atypical A. salmonicida cells produced in iron-limited and iron-supplemented media protected goldfish Carassius auratus when administered by immersion (dosage ≈ 5 × 10⁷ cells/mL for 60 s) followed after 28 d by an oral booster (dosage = 5 × 10⁷ cells/g of feed), which was fed for 7 d so that each fish received about 1 g of vaccine-containing feed. After challenge by intramuscular injection of a virulent culture of atypical A. salmonicida, the relative percent survival (RPS) was more than 90%. The approach was more successful than using a commercial furunculosis vaccine with or without supplementation with A. bestiarum or atypical A. salmonicida cells. Moreover, a smooth derivative of the virulent rough culture of atypical A. salmonicida was less effective as a vaccine candidate, yielding an RPS of only 65%. Low antibody titers of 1:39–1:396 were found in the vaccinated fish. The vaccinated fish had a significantly higher proportion of dead head kidney macrophages (10.9 ± 3.5%; P = 0.0149) than did the controls (6.8 ± 3.1%). However, differences in the number of erythrocytes and leukocytes, the level of phagocytic and lysozyme activities, and the proportion of lymphocytes, monocytes, and polymorphonuclear cells were not statistically significant between the two groups.     

Reactions of goldfish (Carassius auratus) to three suture patterns following full thickness skin incisions

Three different suture patterns (simple interrupted, interrupted horizontal mattress, subcuticular) were placed in a full thickness incision (skin and body wall) of 18 goldfish (Carassius auratus). After 14 days all fish were euthanized using benzocaine solution. The tissue reactions were evaluated by gross visual inspection and histopathological examination. The superficial inflammatory reactions were graded on a scale from 0 (no inflammation) to 3 (severe inflammation). The inflammatory response in histological examination was graded on a scale from 0 (no inflammatory response or normal skin tissue) to 5 (severe inflammatory response and necrosis). The interrupted horizontal mattress induced a moderately severe to severe inflammatory response and necrosis (grades 4–5) but the subcuticular suture induced a very mild to mild inflammatory response (grades 0–1). The simple interrupted suture induced a moderate to moderately severe inflammatory response (grades 2–4). In conclusion, results showed that a subcuticular suture is the most appropriate to use in the closure of a full thickness body wall incision.     

Expression of Aquaporin Water Channels in Equine Endometrium is Differentially Regulated During the Oestrous Cycle and Early Pregnancy

The expression of 12 different aquaporin subtypes in equine endometrium was examined at the mRNA and protein level. Endometrial samples were obtained during anoestrus, oestrus, 8, and 14 days after ovulation in non‐pregnant mares, and 14 days after ovulation in pregnant mares. Quantitative PCR revealed a time‐dependent pattern for all aquaporin subtypes examined except for AQP10 and 12. AQP3, 5 and 7 showed highest mRNA abundance 8 days after ovulation, while AQP0 and 2 were most abundant at Day 14 of the cycle in non‐pregnant mares. At 14 days of pregnancy, AQP1, 4, 8, 9 and 11 displayed highest expression levels. Western blot analysis confirmed protein expression of AQP0, 2 and 5. Immunohistochemistry localized protein expression to luminal and glandular epithelial and stromal cells. AQP0 staining intensity was highest in samples obtained on Day 14 of the oestrous cycle. AQP2 immunoreactivity seemed to be stronger in samples collected 14 days after ovulation from non‐pregnant animals, in particular luminal epithelial staining. Samples collected 8 days after ovulation from cyclic animals were characterized by intense AQP5 staining of glandular epithelium, predominantly in the deeper glands. Progesterone treatment of anoestrous mares did not enhance expression of AQPs, indicating that factors other than progesterone are required for the up‐regulation of certain AQP subtypes during dioestrus. In conclusion, it seems that an equine‐specific collaboration of aquaporin subtypes contributes to changes in endometrial fluid content occurring throughout the oestrous cycle and contributes to endometrial receptivity during early pregnancy in the mare.     

Tissue reaction to Fasciola gigantica in rabbits after treatment with rafoxanide

The tissue reaction to immature Fasciola gigantica was investigated in rabbits experimentally infected with 60 or 100 metacercariae. The rabbits were killed 1, 2, 4, 7, and 14 days after treatment, or 14 days after infection.The histopathological changes of the liver were similar in rabbits killed 1 or 2 days after treatment to those in untreated control rabbits. Dead immature flukes were recognized in the hepatic parenchyma 4, 7, and 14 days after treatment. During the early stage of infection they were surrounded by necrotic liver cells and eosinophils. The intensity of the reaction increased gradually and two distinct zones developed. The inner zone was composed of necrotic liver cells and eosinophils, and the outer zone was composed mainly of phagocytic mononuclear cells and fibroblasts.     

Effects of the β2 -agonist clenbuterol on testicular steroidogenic acute regulatory protein mRNA expression in adult rats

Ma, J.‐K., Zhu, W.‐J. Effects of the β₂‐agonist clenbuterol on testicular steroidogenic acute regulatory protein mRNA expression in adult rats. J. vet. Pharmacol. Therap. 33 , 558–563. This study was carried out to investigate the effects of clenbuterol (CLB) on the testicular (steroidogenic acute regulatory, StAR) protein mRNA expression in rats. Thirty adult male rats were administered CLB by gavage daily at the doses of 0.4, 2.0 and 18.5 mg/kg bw for 14 days in the subacute experiment, whereas 20 rats received a single treatment with CLB at the doses of 20 and 40 mg/kg bw in the acute experiment and 20 rats were treated with 0.9% NaCl solution as vehicle groups. Testicular tissues were collected and snap‐frozen in liquid nitrogen and stored at ?70 °C until use. The levels of StAR mRNA were detected by RT–PCR. The levels of StAR mRNA were markedly increased (P < 0.05) at both dosages of 20 and 40 mg/kg bw but the effects were not dose‐dependent and the mRNA levels of StAR were returned to near normal level after 7 days of CLB withdrawal, compared with the control animals. In the subacute experiment, CLB induced a dose‐dependent but no statistical significant reduction (P > 0.05) in the expression levels of StAR mRNA, and the mRNA levels were recovered to near normal level in the groups treated with CLB at dosages of 0.4 and 2.0 mg/kg bw/day following a 7‐day withdrawal period, compared with the control animals. The mRNA levels of StAR showed a significant decrease in the groups treated with CLB at the dosage of 18.5 mg/kg bw/day (P < 0.05) after a 1‐ or 7‐day withdrawal period with respect to the control animals. These results demonstrated transient stimulative effects of CLB on testicular StAR mRNA levels and inhibitory effects after treatment with CLB for 14 consecutive days.     

Organic acid blend in diets of broiler chickens challenged with Clostridium perfringens

This study was conducted to evaluate the effects of a blend of organic acids (OAs) in diets with or without antibiotic growth promoter (AGP) in chickens challenged with Clostridium perfringens. Day-old male broiler chicks were used in a trial with 4 treatments and 6 replicates of 50 birds per pen, for 43 days, in a completely randomized design. The treatments in a 2×2 factorial arrangement consisted of the presence or absence of enramycin (AGP) and of a blend of OA in the feed. All birds were inoculated at 7 days of age with an anticoccidial vaccine in the drinking water; on days 14, 15, and 16, they were inoculated with C. perfringens in the feed. OA improved weight gain, body weight, and feed intake in the periods 1–7 days and 1–21 days in chicks without antibiotic supplementation. The AGP had the main effect of increasing weight gain and body weight at 35 d; the OA increased weight gain, body weight, and feed intake at 43 days of age. The birds supplemented with OA without AGP had a higher number of CD3+ cells in the ileum mucosa and lower crypt depth than birds supplemented with both OA and antibiotic at 7 days. At 21 days of age, birds fed OA without AGP had higher villus height and a larger villus/crypt ratio; however, there were no differences in the CD3+ cells in the ileal mucosa. The use of OA was beneficial for weight gain and AGP for feed conversion, and the combination of OA and AGP brings complementary advantages in production.     

Evaluation of peripheral lymphocytes after weaning and vaccination for Mycoplasma hyopneumoniae

This study evaluated immune cell populations in pigs following weaning and vaccination for Mycoplasma hyopneumoniae. Piglets (n = 24) were weaned (day 0) at 16 (±1) days of age, and randomly assigned to the vaccination group (n = 16) or control group (n = 8). Complete blood cell counts, flow cytometry and serology were completed for blood samples collected on days 0 (within hours of weaning), 3, 7, 14, 30 and 60. The M. hyopneumoniae S:P ratios (sample optical density: positive control optical density) were negative in the vaccination group until days 30 and 60, when the S:P ratios were 1.3 and 1.0, respectively. Control animals remained serologically negative. The percentage of CD4⁺ T cells was less (P < 0.01) in control pigs than vaccinated pigs at day 3. In contrast, numbers of CD8⁺ and CD4⁺CD8⁺ T cells were greater (P < 0.01) in control pigs than in vaccinated pigs at days 3 and 7. After day 7, few differences in immune cell types were evident between the groups. Differences in lymphocyte populations could not be solely attributed to vaccination, due at least in part, to the confounding influence of weaning. It was difficult to distinguish the influence of vaccination from the impact of weaning on peripheral immune cell populations.     

Histochemistry of nucleoside phosphatases and phosphoglucomutase in the small intestine during coccidiosis in piglets]

The first day after birth, 22 conventional piglets were experimentally infected with the oocysts of the coccidia of I. suis (infection dose 200,000 oocysts). The activity of 5-nucleotidase (5-ribonucleotide phosphohydrolase, EC.3.1.3.5) and phosphoglucomutase (alpha-D-glucoso-1-phosphate phosphotransferase, EC.5.4.2.2) was densitometrically assessed in the mucosa of the small intestines of these piglets. Enzyme activities were studied in the infected piglets during the 2nd to 10th day after infection. The same histochemical examination was simultaneously performed in the intestinal mucosa of five control conventional piglets at an age of 2-14 days. 5-nucleotidase and phosphoglucomutase were found to have a high density in the mucosa of the small intestine of the control piglets: the high-density locations of these enzymes include, first of all, the supranuclear area of the absorption cells, the microvillous zone of enterocytes and the smooth muscle elements of lamina muscularis mucosae. The experimentally infected piglets showed a marked decline of the density of both enzymes during the infection. The deficit affected, for a transient period, the microvillous zone and the supranuclear region of enterocytes; the musculature of the mucous layer was affected permanently. The inactivity was more protracted in the case phosphoglutamase (especially 5 to 9 days after infection). The density of 5-nucleotidase showed a partial return to the normal already the 7th day after infection, with an interruption of resumption of activity on the 10th day. Resumption of enzyme activity in the lamina muscularis mucosae was not recorded during the infection. In the three locations under study, the density of none of the enzymes did reach parameters comparable with the controls at the end of the trial (10 days after infection).     

酵母细胞壁在异育银鲫饲料中添加效果的研究

本试验通过添加酵母细胞壁(YCW)研究其在异育银鲫(Carassius auratus gibelio)饲料中的应用效果。结果表明,饲料中添加0.10%酵母细胞壁饲喂15d后,试验组血清SOD活性极显著高于空白对照组(P<0.01);饲喂30d后试验组血清溶菌酶活性显著高于空白对照组(P<0.05);饲喂60d后试验组背肌中RNA/DNA较空白对照组提高12.18%(P>0.05);饲喂60d后试验组前肠皱褶高度极显著高于空白对照组(P<0.01)。表明饲料中添加0.10%酵母细胞壁对异育银鲫的非特异性免疫力具有明显的促进作用,对其背肌中RNA/DNA和肠道发育也具有一定的促进作用。     

Time-related Pathological Changes in Horses Experimentally Inoculated with Equine Influenza A Virus

To investigate the pathology of equine influenza, necropsy of 7 horses experimentally infected with equine influenza A virus (EIV) subtype H3N8 was conducted on post-infection days (PID) 2, 3, 7, and 14. Histopathologically, rhinitis or tracheitis including epithelial degeneration or necrosis with loss of ciliated epithelia and a reduction in goblet cell numbers, was observed in the respiratory tracts on PIDs 2 and 3. Epithelial hyperplasia or squamous metaplasia and suppurative bronchopneumonia with proliferation of type II pneumocytes were observed on PIDs 7 and 14. Viral antigen was detected immunohistochemically in the epithelia of the nasal mucosa, trachea, and bronchi on PIDs 2 and 3. The sodA gene of Streptococcus equi subsp. zooepidemicus, a suspected cause of suppurative bronchopneumonia, was detected in paraffin-embedded lung tissue sections, but only on PIDs 7 and 14. These findings suggest that damage caused to ciliated epithelia and goblet cells by EIV infection results in secondary bacterial bronchopneumonia due to a reduction in mucociliary clearance.     

Genetic selection for resistance to mycoplasmal pneumonia of swine (MPS) in the Landrace line influences the expression of soluble factors in blood after MPS vaccine sensitization

We recently developed a Landrace line that is resistant to mycoplasmal pneumonia of swine (MPS) infection by genetic selection for five generations, and we reported that the immunophenotype of this line is different from that of the non‐selected line in terms of changes in peripheral blood leukocyte population after MPS vaccination. This study followed up previous findings demonstrating changes in soluble factors in blood, namely, hormones, Mycoplasma hyopneumoniae‐specific immunoglobulin G (IgG), and cytokines. These two lines were injected with MPS vaccine on days ?7 and 0 after blood sampling on those days, and blood samples were collected on days ?14, ?7, 0, 2, 7 and 14. We found changes in the levels of many hormones and cytokines in both lines. However, we found that only growth hormone (GH) and interferon (IFN)‐γ levels were statistically different between these two lines. GH concentration was reduced (day 0) and IFN‐γ concentration was increased (day 14) in the MPS‐selected line compared with the non‐selected line, despite unchanged IFN‐γ messenger RNA expression in blood cells. Although detailed mechanisms underlying these phenotypes remain unsolved, these traits would be useful to improve MPS resistance in pig production and provide an insight into MPS infection.     

枯草芽孢杆菌048对雪山草鸡抗肠炎沙门氏菌感染能力的影响

本试验旨在研究枯草芽孢杆菌(BS)048对雪山草鸡抗肠炎沙门氏菌(SE)感染能力的影响。选择240只体重(61.5±0.5)g的1日龄雪山草鸡公鸡(SE阴性),随机分为4组,每组设3个重复,每个重复20只鸡。对照组和对照感染组饲喂基础饲粮,BS组和BS感染组饲喂添加0.1%(质量分数)BS048的基础饲粮。对照感染组和BS感染组在5~7日龄时每天以1×108CFU的SE感染试验鸡只,试验期14 d。测定BS048对正常和SE感染雪山草鸡盲肠黏膜、肝脏、肾脏SE载菌量,血清免疫球蛋白(Ig)和回肠分泌型免疫球蛋白A(s Ig A)含量,空肠黏膜碱性磷酸酶(ALP)、髓过氧化物酶(MPO)、总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性与总抗氧化能力(T-AOC)以及丙二醛(MDA)含量的影响。结果表明:1)与对照组相比,BS组显著提高了雪山草鸡8、10、14日龄回肠s Ig A含量(P0.05),显著提高了10、14日龄空肠黏膜ALP活性(P0.05),极显著提高了10、14日龄的空肠黏膜T-AOC及T-SOD、GSH-Px活性(P0.01),显著降低了8、14日龄的空肠黏膜MDA含量(P0.05)。2)与对照感染组相比,BS感染组极显著减少了SE感染雪山草鸡盲肠黏膜、肝脏和肾脏SE载菌量(P0.01),显著提高了10、14日龄的血清Ig A、Ig G、Ig M及8、10、14日龄的回肠s Ig A含量(P0.05),显著提高了8、10、14日龄的空肠黏膜ALP活性P0.05),极显著降低了8、10、14日龄的空肠黏膜MPO活性(P0.01),显著或极显著提高了8、10、14日龄的空肠黏膜T-AOC及T-SOD、GSH-Px活性(P0.05或P0.01),显著或极显著降低了8、10、14日龄的空肠黏膜MDA含量(P0.05或P0.01)。由此可见,BS048能够增强雪山草鸡的抗SE感染能力。     

Attenuation of virulence of Lawsonia intracellularis after in vitro passages and its effects on the experimental reproduction of porcine proliferative enteropathy

Non-pathogenic Lawsonia intracellularis variants have been obtained through multiple passages in cell culture but there is no information regarding the number of passages necessary to attenuate a pathogenic isolate. The present study evaluated the susceptibility of pigs to L. intracellularis after 10, 20 and 40 passages in vitro. Three groups (six animals/group) were inoculated with pure culture of L. intracellularis on passage 10, 20 or 40 and one group with placebo. The animals were monitored for clinical signs, fecal shedding and serological IgG response during 28 days post-inoculation. Gross and histologic lesions and the level of infection based on the amount of L. intracellularis-specific antigen in the intestinal mucosa identified by immunohistochemistry were evaluated in two animals from each group on days 14, 21 and 28. Animals inoculated with passages 10 and 20 demonstrated proliferative lesions typical of porcine proliferative enteropathy associated with the presence of Lawsonia-specific antigen in the intestinal mucosa. Passage 40-inoculated pigs did not show proliferative lesions or presence of Lawsonia antigen at any time point throughout the study. Similar patterns of the fecal shedding were observed in passage 10 and 20-infected pigs but those infected with passage 40 shed for a short period. Serological IgG responses in passage 10 and 20-inoculated pigs were detected from day 14 post-infection but not at all in passage 40-inoculated animals. These results demonstrate attenuation of the virulence properties of L. intracellularis between 20 and 40 cell passages in vitro. This information will be valuable for design of future experimental models and for studying the mechanisms involved in the attenuation of L. intracellularis virulence.     

Distribution and Expression of Recombinant Plasmid Encoding Chicken Interleukin-2

A plasmid DNA that encodes chicken interleukin-2 (pCI-ChIL-2-EGFP) was investigated for its distribution and expression after intramuscular (i.m.) injection in chickens. After the i.m. injection, serum distribution was detectable from 2 h post inoculation (p.i.), peaked at 8 h p.i., and disappeared at 7 days p.i. The plasmid DNA was also observed in several organs including heart, liver, lung, spleen, bursa and inoculated muscle at different time points, but at 19 days p.i. the plasmid DNA was not found in any organ except inoculated muscle. Fluorescence of enhanced green fluorescent protein (EGFP) was found in cytoplasm and nucleus of cultured Vero cells, chicken embryo fibroblasts and peripheral blood lymphocytes, which were transfected in vitro with the plasmid DNA or in vivo with Lipofectamine. The expression profile of the fusion gene (ChIL-2-EGFP) in vivo was measured by RT-PCR, ELISA and fluorescence microscopy. The EGFP expression was detected from 8 h p.i. to 14 days p.i. and peaked at 5 days p.i., when the number of EGFP-expression myocytes was about 5% in the injected site. These results demonstrate that intramuscular administration of plasmid DNA leads to widespread distribution and long-term expression in vivo.     

Preservation of common carp germ cells under hypothermic conditions: Whole tissue vs isolated cells

The aim of this study was to optimize the conditions for hypothermic storage of spermatogonial stem cells (SSCs) and oogonial stem cells (OSCs) of common carp Cyprinus carpio. This was conducted by storing gonadal tissue or isolated cells for 24 hr under hypothermic conditions in the first experiment and by testing two different storage media (L‐15 or DMEM supplemented with 10% FBS and 25 mM HEPES) and regular medium change (every 4 days) during two weeks of hypothermic storage in the second experiment. During the first 24 hr, isolated cells showed no decrease in viability, while cells obtained from hypothermically stored tissues displayed significantly lower viability after only 6 hr (Tukey's HSD, p < 0.01) indicating that hypothermic storage of isolated cells is superior to storing tissue pieces. The 2‐week trial demonstrated that storage media have a profound influence, while regular medium exchange does not have a positive effect on cell viability. Viability of SSCs and OSCs after two weeks was approximately 40% and 25%, respectively; however, survival of ~70% was obtained after 10 days of storage for SSCs and 7 days for OSCs. Hypothermic storage developed in this study has many practical applications during the development of surrogate broodstock technologies for common carp, but also in carp hatcheries and for the conservation of genetic resources of closely related cyprinid species.     

地衣芽孢杆菌对发酵床饲养仔猪生长性能、消化酶活性及肠道主要菌群数量的影响

本试验旨在研究发酵床饲养模式下日粮中添加地衣芽孢杆菌对仔猪生长性能、胰腺和小肠黏膜消化酶活性及肠道主要菌群数量的影响。选用108头体重13kg左右的35日龄健康苏钟猪,随机分为3组,每组3个重复,每个重复12头,分别饲喂基础日粮(对照组)、基础日粮+40mg/kg杆菌肽锌+20mg/kg硫酸黏杆菌素(抗生素组)、基础日粮+300mg/kg地衣芽孢杆菌(益生菌组)的试验日粮。预试期7d,正试期52d。结果表明:1与对照组相比,日粮中添加地衣芽孢杆菌能够在一定程度上提高仔猪平均日增重、平均日采食量,降低料重比,但各组间差异均不显著(P0.05)。2与对照组相比,日粮中添加地衣芽孢杆菌能够极显著提高仔猪胰腺中淀粉酶活性、十二指肠黏膜中麦芽糖酶活性和空肠黏膜中乳糖酶活性(P0.01),十二指肠黏膜和空肠黏膜中蔗糖酶活性显著提高(P0.05)。3与对照组相比,日粮中添加地衣芽孢杆菌能够显著提高仔猪盲肠芽孢杆菌数量(P0.05);乳酸杆菌数量较对照组提高4.09%,大肠杆菌数量较对照组降低4.86%,但均未达到显著水平(P0.05)。综上所述,在本试验条件下,日粮中添加300mg/kg地衣芽孢杆菌能够提高发酵床饲养仔猪胰腺、小肠黏膜消化酶活性及盲肠芽孢杆菌数量,同时仔猪生长性能也在一定程度上有所改善。     

The Content of β-endorphin-like Immunoreactivity in Porcine Corpus Luteum and the Potential Roles of Progesterone, Oxytocin and Prolactin in the Regulation of β-endorphin Release from Luteal Cells in vitro

The amount of β‐endorphin‐like immunoreactivity (β‐END‐LI) in porcine corpora lutea from several stages of the oestrous cycle and the effects of progesterone, oxytocin, and prolactin on β‐END‐LI secretion in vitro by luteal cells were studied. Porcine corpora lutea obtained on days 1–5, 6–10, 11–13, 14–18, and 19–21 of the cycle were used to prepare extracts for β‐END‐LI determination. Additionally, corpora lutea from days 11–13 and 14–18 were enzymatically dissociated and isolated luteal cells were used for further study of β‐endorphin secretion in vitro. Cells were cultured in serum‐free defined M 199 medium (10⁶ cells/ml) at 37°C under 5% CO₂ in air, for 12 h. The influences of the following factors on β‐END‐LI secretion by luteal cells were tested: progesterone (10^–9, 10^–7 and 10^–5M ), oxytocin (0.01, 0.1, 1 and 10 ng/ml), and prolactin (0.1, 1, 10 and 100 ng/ml). The β‐END‐LI contents in extracts and media were measured by radioimmunoassay. The tissue concentration of β‐END‐LI was lowest on days 1–5 of the cycle (0.35 ± 0.03 ng/g wet tissue). Subsequently, it constantly increased to the highest value on days 14–18 (16.58 ± 0.52 ng/g wet tissue) and on days 19–21 it declined (11.10 ± 0.52 ng/g wet tissue). Progesterone at a low dose (10^–9 M ) resulted in significant (p < 0.05) increases and decreases in β‐END‐LI secretion by luteal cells from days 11–13 and 14–18, respectively. Higher doses of progesterone (10^–7 and 10^–5 M ) had no effect on β‐END‐LI release, compared with the control group. All dose‐levels of oxytocin used decreased β‐END‐LI secretion by luteal cells on days 11–13 and 14–18 of the cycle. Prolactin at doses of 0.1 and 1 ng/ml on days 11–13, and all doses tested on days 14–18 resulted in decreases in β‐END‐LI release from luteal cells. These results document evident changes in β‐END‐LI content in the pig corpus luteum during its development and indicate the potential roles of progesterone, oxytocin, and prolactin in luteal cell secretion of β‐END‐LI.