The Level of Prolactin,Serum Amyloid A,and Selected Biochemical Markers in Mares Before and After Parturition and Foal Heat

The aim of the study was to determine the level of prolactin (PRL), serum amyloid A (SAA), and selected biochemical markers (T-Chol, AST, TP, Mg²⁺, P⁺, and Ca²⁺) in the blood of mares during the perinatal period. The study involved 14 mares of the Polish Coldblood Horse breed, which were in the third trimester of pregnancy. Blood was collected for testing 2 weeks before parturition and then 24 hours after delivery and in the foal heat (9 days) and 9 days after ovulation and breeding. The research revealed significant differences in the level of PRL and SAA before and after delivery. The highest PRL level was found 24 hours after delivery, lowest in foal heat and 9 days after ovulation. Serum amyloid A concentration was within the accepted norms; however, on day 9 after foaling, a significant increase of this protein was observed. All biochemical markers were within physiological limits. However, significant increases in T-Chol, AST, and TP levels was observed 24 hours after the delivery, whereas in foal heat and after ovulation levels of T-Chol and TP significantly decreased and the AST level remained at a similar level. There were no significant changes in electrolyte levels such as Mg²⁺, P⁺, and Ca²⁺. The pregnancy rate in the foal heat was at 43%. Collectively, the results of this study in conjunction with clinical observations demonstrated that when the perinatal period was normal, no disturbances in health related to pregnancy, parturition, lactation, and reproductive status during the postpartum period were found.     

Feasibility and Safety of Endometrial Injection of Autologous Bone Marrow Mesenchymal Stem Cells in Mares

​Chronic degenerative endometritis (CDE) is an important cause of fertility problems in older mares. It is estimated that 30% of mares breeding are over 18 years old and the high value of their progeny encourages the use of these animals in assisted reproduction procedures. Currently, cell-based therapies are broadly used in human and veterinary regenerative medicine and have been showed a good effect on the treatment of liver fibrosis. Thus, the present study aimed to evaluate the feasibility and safety of endometrial injection of autologous bone marrow MSCs in mares. Mares were examined by transrectal ultrasound and the endometrial stem cells injections performed during diestrous, using injection needles coupled to a teflon catheter through the biopsy channel of a flexible endoscope. After treatment clinical evaluations (heart reat, respiratory rate, staining of the mucosa, capillary refill time, body temperature and lameness score) were performed daily during seven days. The intrauterine fluid and endometrial edema was evaluated before, 24 and 48 hours after the procedure by ultrasonographic exams and the inflammatory infiltrate (polymorphonuclear cells and mononuclear cells) and degree of fibrosis by histological evaluations before (D0) and 15 (D15), 30 (D30) and 60 (D60) days after endometrial injections. The results were evaluated by Kolmogorov-Smirnov and Kruskal-Wallis test followed by Dunn test and for fertility rates was used Chi-square, considering a 5% significance level. Neither clinical alteration was observed in mares after treatment, as well as, intrauterine fluid and endometrial edema were not detected in any mare before and after cell therapy. After cell therapy, significantly more PMNs were found in D15 biopsies, however, these cells were not observed in D30 and D60 biopsies. No worsening on the histological architecture after treatment was observed in any mare. In conclusion, the results of this study showed that endometrial hysteroscopic injections of stem cells in mares is a safe procedure.     

Comparison of the Cytology Brush and Cotton Swab in the Cytological Evaluation of the Endometrium in Mares with Regard to Fertility

The aim of this study was to compare the cytology brush (CB) and cotton swab (CS) in the cytological evaluation of the endometrium in mares with regard to fertility. The study was conducted on 26 mares displaying spontaneous estrus. Samples for cytological evaluation were taken from each mare by using commercially available CS and CB. After sample collection, all mares were mated in the same estrus, and pregnancy diagnosis was performed 14-18 days after last mating. No vaginal cells were found in smears, and the CB technique yielded significantly more cells/high-power field (HPF) than the CS technique. Additionally, more cases of endometritis were diagnosed using the CB than the CS. It was also shown that the degree of inflammation is more important in diagnosis of infertility in the mare than the mere presence or absence of inflammation. In conclusion, further studies are needed to establish more precise criteria for the interpretation of inflammation, especially if samples are collected using the CB.     

Age-Dependent Effect of Foal Heat Breeding on Pregnancy and Embryo Mortality Rates in Thoroughbred Mares

The aim of the present study was to evaluate the correlation of age and heat cycle to determine reproductive efficiency in young and aged Thoroughbred mares bred on foal heat (FH) or on second heat (SH) after foaling. Embryo mortality (EmbM) was determined every time a mare was found open after a positive pregnancy diagnosis. Parturition to breeding interval, pregnancy rate (PregR) and EmbM rate were the dependent variables and the treatments were breeding on the FH or on SH. The cutoff age to obtain above-average probability for the EmbM was 10 years old. PregR in mares bred on FH was lower compared with SH (P < .01); however, it was neither affected by the age of mares (P > .05) nor by the age group of mares (P > .05). Regarding FH and SH, there was a difference in PregR in young mares (P < .01), unlike in aged mares (P > .05). EmbM rate was not different between mares bred on FH or SH (P > .05) although it was affected by age of mares (P < .01). EmbM was higher in oldest than young mares (P < .01). Aged mares bred on FH had a significantly higher EmbM rate compared with the young group also bred on FH (P < .01). In conclusion, the reproductive efficiency of Thoroughbred mares bred on FH is dependent of the age. Aged mares (≥10 years old) should be bred at their SH to reduce EmbM and improve reproductive performance.     

Relationship Between Neutrophil Activity,Oxidative Stress,Acute Phase Response,and Lameness Grade in Naturally Occurring Acute and Chronic Joint Disorders in Horses

We hypothesized that in horses with naturally occurring joint disorders, the neutrophil response, acute phase response (APR), and oxidative stress parameters elevated significantly and are markers of increased inflammatory response in these conditions. Therefore, the first aim of the study was to evaluate neutrophil response, oxidative status, and APR. The neutrophil activity was assessed on the basis of elastase, myeloperoxidase (MPO), and alkaline phosphatase release, whereas free radical generation was assessed on the basis of nitric oxide and superoxide production. Acute phase response was estimated on the basis of fibrinogen or haptoglobin plasma concentration and oxidative stress on the basis of malondialdehyde plasma concentration. Then, these parameters were compared with lameness grade, and correlation coefficients between them were calculated. The study was conducted on 43 horses divided on control group of healthy horses (n = 17), acute lameness (AL) group (11 horses), and chronic lameness (CL) group (15 horses). The neutrophil activity from horses of both groups of joint disorders (AL and CL) was significantly (P < .01) higher in comparison with healthy horses. Elastase release was 67.28 ± 1.89% of maximal activity in AL group in comparison with 51.72 ± 1.75% in healthy horses and 62.61 ± 1.54% in CL group. The highest values of other enzymes were also noted in AL group. Moreover, in AL group release of elastase and MPO positively correlated (P < .01) with grades of lameness. These findings revealed the mutual relation between studied parameters and obtained results may be useful in the development of new therapeutic strategies in the treatment of acute and chronic joint disorders in horses.     

Development and Comparison of Sampling Techniques for a Broad Range,Semiquantitative Polymerase Chain Reaction Assay for Detection of Bacterial DNA in the Equine Uterus

Microbial culture from a double-guarded culture swab is commonly used to diagnose infectious endometritis. The objective of this study was to develop a quantitative polymerase chain reaction (qPCR) assay to detect a broad range of bacteria from equine uterine samples. Twenty-seven mares with a clinical history of endometritis had a double-guarded culture swab collected for analysis by qPCR and microbial cultures. An additional 12 mares had a uterine biopsy sample collected for qPCR analysis, microbial culture, and histopathology. Subsequently, a double-guarded culture swab for microbial culture and a cytology brush sample were also collected. The qPCR assay detected bacterial DNA in nine of 27 mares from a double-guarded swab and six of 12 mares from an endometrial biopsy. Positive microbial growth was detected in nine of 27 mares and four of 12 mares from a double-guarded culture swab. Bacterial DNA was detected in two of 27 mares and two of 12 mares without subsequent microbial growth. The simple presence of an organism's DNA allows for detection by nonculture-based systems, both live and dead organisms can be identified. In conclusion, the qPCR assay was determined to be a sensitive diagnostic technique for identifying pathogens associated with infectious endometritis. The primary application of the qPCR assay is detection of potential pathogenic bacteria in the uterus of a mare suspected of having infectious endometritis when a traditional microbial culture is negative. Further work is warranted to determine if mares positive for bacterial DNA and negative for microbial culture are affected clinically.     

渗透胁迫对柠条叶片脂质过氧化及抗氧化酶活性的影响

采用PEG溶液对不同海拔下的柠条叶片进行渗透胁迫处理并对其生理响应进行了探讨.结果表明,在渗透胁迫下兰州市九州台山下的柠条叶片相对含水量、丙二醛含量和活性氧水平较低,脯氨酸含量较高,耐渗透胁迫的能力较强.SOD、POD和CAT三种抗氧化酶的活性在渗透胁迫下变化不一致,但总体表现为在轻度胁迫时升高,胁迫加重时下降的趋势.相关分析表明,渗透胁迫下柠条叶片各生理指标之间存在广泛的关联,说明多种因素影响柠条的抗旱性;相对含水量与脯氨酸含量显著负相关,与SOD活性呈显著正相关,说明叶片相对含水量低可能是其抗渗透胁迫能力较强的关键因素.     

Relationship Between Fertility at Foal Heat and Blood Biochemistry Parameters Monitored During the Peripartum Period in Thoroughbred Mares

This study aimed to examine fertility at foal heat and its relevance to body condition score (BCS) and blood nutritional metabolites in Thoroughbred mares. Thoroughbred mares foaled from 2006 to 2009 were included and classified into two groups: group C (conception; n = 34), which included mares that conceived during foal heat (within 3 weeks after foaling), and group NC (nonconception; n = 39), which included mares that did not conceive despite mating during their foal heat. BCS and blood samples were obtained 1 month before the expected foaling date and 1, 2, 3, and 4 weeks after foaling. Total protein (TP), albumin (Alb), blood urea nitrogen (BUN), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), total cholesterol (T-Cho), triglyceride (TG), nonesterified fatty acid (NEFA), calcium (Ca), inorganic phosphate (iP), and magnesium (Mg) levels were measured using an automatic clinical chemistry analyzer. Repeated measures analysis of variance (ANOVA) and Student t-test were used to examine the differences between the two groups. No significant differences were observed between the two groups in any of the above-mentioned parameters at 1 month before the expected foaling date (Student t-test). Furthermore, no significant differences were observed between the two groups in serum levels of TP, Alb, AST, GGT, T-Cho, NEFA, Ca, and Mg and BCS at postpartum periods (repeated measures ANOVA). Serum TG, BUN, and iP levels remained lower in group NC than in group C after foaling (P < .05, repeated measures ANOVA). Although the mechanism by which these nutritional factors affect a decline in reproductive performance remains unclear, our results suggest that blood biochemical tests can detect potential imbalances in nutrition and metabolism, even if there is no difference in BCS.     

A Field Study of Serum,Colostrum, Milk Iodine,and Thyroid Hormone Concentrations in Postpartum Draft Mares and Foals

Iodine, thyroxine (T4) and triiodothyronine (T3) are required for normal fetal growth, maturation, and neonatal survival. There is a lack of robust information on iodine levels found in colostrum, milk, and serum of mares and foals after a healthy pregnancy. Our objective was to characterize colostrum, milk, and serum iodine levels in healthy postpartum mares and foals (n = 10) and explore relationships with thyroid hormone concentrations. Colostrum, milk, and jugular blood samples from draft breed mares and foals with an estimated average iodine daily intake of 39 mg per mare during pregnancy were obtained at Day 0 (foaling date) and/or 10 days later. Parameters studied were (1) mare basal concentrations of serum: TT3, TT4, and iodine; (2) iodine in colostrum at Day 0 and milk iodine (Day 10); and (3) foal basal: TT3, TT4, and serum iodine (Days 0 and 10). Median ± median error colostrum iodine levels (165 ± 15.1 μg/L) were higher than milk (48 ± 5.6 μg/L; P = .007) levels. Median ± median error foal serum iodine (268.5 ± 7.6 μg/L), TT4 (1,225 ± 47.8 nmol/L), and TT3 (14.2 ± 1.1 nmol/L) at foaling date were higher than at 10 days (serum iodine: 70 ± 3.6 μg/L; TT4: 69.6. ± 20.4 nmol/L; and TT3: 5.4 ± 0.3 nmol/L). In conclusion, equine mammary tissue concentrates iodine beyond plasma levels, making colostrum and milk a significant source of iodine. Foal serum iodine levels are high in the neonatal period and are positively correlated with TT4, which is important for neonatal adaptation.     

鹿胎制剂及其对老年雌性大鼠血清脂质过氧化和抗氧化酶活性的影响

以老年雌性大鼠为试验动物,研究了16个鹿胎制剂组方对老年大鼠血清脂质过氧化和抗氧化酶活性的影响。结果表明:鹿胎制剂能显著降低大鼠血清MDA含量(P<0.01)。大鼠血清SOD活性提高了17.78%(P<0.05);说明鹿胎制剂具有不同程度抗脂质过氧化作用。从抗脂质过氧化作用效果看,鹿胎制剂组方,鹿胎粉、西洋参、中药C、中药D和蜂花粉的最佳配比为40∶5∶0.9∶2∶16。     

Dynamics of Follicular Blood Flow,Antrum Growth,and Angiogenic Mediators in Mares From Deviation to Ovulation

This study aimed to investigate dynamics of dominant and subordinate follicles' change of dimensions, vascularity, and angiogenic hormones from deviation to ovulation. Ten cyclic mares were subjected to daily blood sampling and Doppler examination along two estrous cycles. Three diameters were recorded for each follicle to estimate its area and volume. Leptin, insulin-like growth factor-I (IGF-1), nitric oxide (NO) and estradiol were measured. Area of color and power Doppler modes with antral area and circumference of all follicles was measured in pixels. Follicles were classified into first large preovulatory follicle (1st F-ov), second large (2nd F-ov), and third large (3rd F-ov) on the ovulating ovary and on the contralateral nonovulating ovary into first (1st F-contra) and second large (2nd F-contra). Days before ovulation significantly (P < .0001) affected all dimensions of preovulatory follicle. With the increase of diameter, area, volume, area in pixel, antrum area, and circumference of 1st F-ov, those of all subordinates were decreasing. The blue flow area, power, and power minus red blood flow area of 1st F-ov increased from day −6 till day of ovulation (day 0), but red blood flow area significantly decreased. First large follicle had the lowest percent of colored pixels and percent of the colored pixels without antrum. Estradiol and leptin increased from day −6 till day 0, but IGF-1 decreased till day −1 and NO achieved a peak on day −3 then decreased till day 0. In conclusion, antrum growth, blood flow, and angiogenic hormones play a role in maturation and ovulation of the dominant follicle in mares.     

Glutathione Peroxidase Activity and Erythrocyte Lipid Peroxidation as Indices of Selenium and Vitamin E Status in Young Pigs

A randomized, blocked 2³ factorial experiment was conducted with 48 pigs from sows fed a diet low in selenium and vitamin E. From 3 to 12 weeks of age the piglets were kept in single pens and fed a basic diet consisting mostly of barley, dried skim milk, soybean meal and dried yeast, and containing 55 µg selenium and 3 mg vitamin E per kg. The treatment factors — i.e. feed supplements — were 2 levels of Se (nil, 60 µg/kg), 2 levels of vitamin E (nil, 50 mg/kg), and 2 levels of the feed antioxidant ethoxyquin (nil, 150 mg/kg). Blood samples, collected at termination of the experiment, were examined for glutathione peroxidase activity (GSH-Px) and resistance against erythrocyte lipid peroxidation (ELP) to evaluate Se and vitamin E status, respectively. Analysis of variance showed the GSH-Px activity to be litter-dependent (P < 0.001) and influenced by selenium supplementation (P < 0.001) but not by the other supplements or by interactions between supplements. Resistance against ELP was influenced only by vitamin E supplementation (P < 0.001). GSH-Px and ELP thus seem to be valuable and simple methods for evaluating, respectively, Se status and vitamin E status in growing pigs.     

Stallion-like Behavior in Mares: Review of Incidence, Characteristics, Ovarian Activity, and Role of Testosterone

Stallion-like sexual behavior in mares is rare, except in association with ovarian tumors or hormonal treatments. The rarity of the phenomenon was confirmed in a recent 3-year study. The mean number of mares with detected stallion-like behavior, including mounting with thrusts, during an entire ovulatory season was 5.7 (17/3 years) in a herd averaging 105 mares (5% incidence/mare/season). From a total of 17 mountings of an estrous mare by another mare, 15 occurred when the mounting mare was in the follicular phase and two when in the early luteal phase. Plasma testosterone concentration on the day of mounting was higher (P < 0.01) in the mounting mares (17.7 ± 2.3 pg/ml) than in the standing mares (10.9 ± 0.5 pg/ml). No other deviation in the endocrine, behavioral, or morphologic aspects of the estrous cycle was observed. In another study, testosterone was assayed daily from 7 days before to 4 days after ovulation in seven mares during estrous cycles with no detected mare-on-mare mountings. Concentrations during the follicular phase were highest on the days corresponding to when mare-on-mare mounting was detected in the previous study. It is concluded that the rare occurrence of stallion behavior by untreated mares with no detected ovarian tumors is a consequence of an unusually high, apparently transient fluctuation in circulating testosterone at the time of mounting.     

游泳应激对小鼠肾脏、肺脏和脑组织脂质过氧化状态的影响

为探讨游泳应激对小鼠肾脏、肺脏和脑组织脂质过氧化水平的影响,本试验选取50只小鼠进行游泳试验,于游泳前、游泳10、20、30、50 min后分别随机选取10只小鼠眼眶采血致死,采集肾脏、肺脏和脑组织,测定样品中MDA含量、SOD和GSH-Px活性。结果表明,10或20 min游泳应激后,小鼠肾脏、肺脏和脑组织MDA含量均显著增加(P<0.05),之后均有不同程度的降低;游泳过程中小鼠肾脏SOD活性持续升高,30和50 min后均显著升高(P<0.05),游泳20 min后肺脏SOD活性显著降低(P<0.05),30 min后有所回升,50 min后又轻微下降,游泳过程中脑组织SOD活性均无显著性变化;游泳20和30 min后,肾脏GSH-Px活性显著增加(P<0.05),50 min后显著下降(P<0.05),游泳前40 min过程中肺脏GSH-Px持续下降,30 min组显著降低(P<0.05),游泳10和20 min后,脑组织GSH-Px活性显著降低(P<0.05),之后发生波动性变化。结果提示,游泳应激显著影响小鼠肾脏、肺脏和脑组织脂质过氧化水平,推测游泳应激可能引起小鼠全身脂质过氧化反应。     

脱氧雪腐镰刀菌烯醇暴露对断奶仔猪延髓脂质过氧化反应、神经递质及钙稳态的影响

旨在通过脱氧雪腐镰刀菌烯醇(DON)体内暴露试验,检测仔猪延髓组织的脂质过氧化反应、神经递质分泌及钙稳态的变化,研究DON对仔猪的神经毒性作用。选取30头21日龄"杜×长×大"三元杂交断奶仔猪,随机分为对照组、DON低剂量组和DON高剂量组,每组10头仔猪。对照组饲喂基础饲料,DON低剂量组和高剂量组分别饲喂含1、2 mg·kg^-1DON的饲料,试验期为60 d。试验结束时,每组随机选择5头仔猪屠宰,采集延髓组织,检测氧化与过氧化水平、神经递质含量和Ca²⁺浓度、钙调蛋白(CaM)与钙调蛋白依赖性激酶Ⅱ(CaMKⅡ)mRNA相对表达量及CaM、CaMKⅡ、p-CaMKⅡ的蛋白表达水平。结果显示:与对照组相比,DON高、低剂量组脂质过氧化指标超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性极显著降低(P<0.01),而一氧化氮(NO)浓度极显著升高(P<0.01);DON高、低剂量组神经递质5-羟色胺(5-HT)浓度极显著升高(P<0.01),而乙酰胆碱(ACH)浓度极显著降低(P<0.01),高剂量组多巴胺(DA)和γ-氨基丁酸(GABA)浓度显著下降(P<0.05);DON高、低剂量组钙稳态指标Ca²⁺浓度均极显著升高(P<0.01),低剂量组CaM mRNA表达量显著降低(P<0.05),高、低剂量组CaMKⅡmRNA表达量均极显著降低(P<0.01);DON高剂量组CaM蛋白表达水平极显著降低(P<0.01),而p-CaMKⅡ蛋白表达水平极显著升高(P<0.01)。试验结果表明,DON暴露能够改变仔猪延髓组织脂质过氧化反应及神经递质的分泌,并导致钙稳态紊乱,对断奶仔猪具有一定的神经毒性作用。     

Effects of Triiodothyronine-induced Hyperthyroidism on Lipid Peroxidation,Erythrocyte Resistance and Iron-binding and Iron-oxidizing Antioxidant Properties of Plasma in the Rabbit

The effect of hyperthyroidism on some oxidative stress parameters is reported. The hyperthyroid state was induced by intraperitoneal injection of triiodothyronine (T₃)(10 μg/kg body weight) for 14 days in two groups of female rabbits (3 and 12 months old). The T₃ injection caused increase by 1.5-fold to 1.7-fold in T₃ serum level, and 2-fold to 3-fold decrease (age-dependent) in body weight gain at the end of experimental period. The induced hyperthyroidism caused a significant increase in the serum concentration of the lipid peroxidation end-product malondialdehyde and lowered erythrocyte resistance to oxidative stress when subjected to the free radical generator 2,2'-azobis(2-amidinopropane) hydrochloride in vitro. The half maximum haemolysis time (HT₅₀) decreased in the both experimental groups of rabbits, by about 12 min in the 3-month-old animals and 27 min in the 12-month-old animals. The study showed for the first time that hyperthyroidism enhances the ability of plasma to protect against iron-binding and iron oxidizing organic radicals. The scavenging property and antioxidant capacity of plasma against iron-binding inorganic radicals also increased. Measurement of erythrocyte resistance to oxidative stress and the protective ability of plasma against oxygen radicals discriminates the thyroid hormone modulatory effects in defence mechanisms against lipid peroxidation.     

Status of Lipid Peroxidation, Antioxidants, and Oxidation Products of Nitric Oxide in Equine Babesiosis: Status of Antioxidant and Oxidant in Equine Babesiosis

Equine babesiosis is a tick-borne protozoal disease of horses caused by Theileria equi and Babesia caballi. The disease is endemic in most tropical and subtropical areas. The aim of this paper is to assess the antioxidant status, lipid peroxidation, and oxidation products of nitric oxide (NO) in horses and mules naturally infected with T. equi and B. caballi. East and Southeast Anatolian horses and mules living in rural region of the Eastern border of Turkey were used as the material for this study. These animals are used as pack animal (3–7 years of age). Infected animals were in acute or subacute infection period. In the current study, malondialdehyde (MDA), oxidation products of NO (nitrate and nitrite), serum glutathione (GSH), vitamin E, and retinol levels were analyzed in 58 equids (horse and mule) infected with T. equi and B. caballi as well as in 44 healthy equids. Compared with controls, the level of MDA and nitrate increased significantly (P < .01, P < .05, respectively), whereas GSH concentration and levels of vitamin E decreased significantly (P < .01). There was no significant change in the level of nitrite and retinol between two groups. The results of the current study suggest that in equids infected with T. equi and B. caballi, this alteration in the lipid peroxidation, oxidants, and antioxidants may be related to the host's defenses against parasitic infection and may play a central role in the pathologic conditions associated with babesiosis.     

贝加尔针茅草原土壤酶活性及微生物量碳氮对养分添加的响应

通过草地养分添加控制试验,研究了贝加尔针茅(Stipa Baicalensis)草原在CK,K,P,N,PK,NK,NP,NPK不同养分添加方式下土壤酶活性、土壤微生物量碳氮的变化以及他们与土壤养分间的相互关系。结果表明:土壤蔗糖酶在含磷养分添加条件(NP,NPK,P,PK)下活性显著高于CK,脲酶活性在氮磷组合添加条件下(NP,NPK)下有显著提高,碱性磷酸酶活性在NP,NPK和NK处理下有显著的提高,过氧化氢酶在不同养分添加条件下活性与CK无显著差异;NP,NPK,N和PK处理下微生物量碳显著高于其他处理,NP处理下微生物量氮显著高于CK;过氧化氢酶、蔗糖酶活性与速效磷含量呈显著正相关,微生物量碳与脲酶和碱性磷酸酶活性呈显著正相关,与蔗糖酶活性呈极显著正相关,微生物量氮与速效磷、过氧化氢酶、蔗糖酶和脲酶活性呈显著正相关。综合分析表明,氮磷养分组合添加可以提高贝加尔针茅草原土壤酶活性和微生物量碳氮含量,有利于土壤肥力状况改良。     

Tail-in-mouth Behaviour Among Weaner Pigs in Relation to Age,Gender and Group Composition Regarding Gender

Male pigs are significantly more often found to be tail-bitten at slaughter than are females. Age is also thought to be a crucial factor in relation to the ontogeny of tail-biting among slaughter pigs. Tail-in-mouth behaviour (TIM) among young pigs is probably the precursor of the damaging tail-biting in older pigs. Hence, this experiment aimed to elucidate the frequency of TIM in relation to gender, age and group composition regarding gender in weaner pigs. Pigs were reared in groups of 24 until 5 weeks of age and then divided into three groups: (A) eight female pigs, (B) eight castrated male pigs and (C) four female and four castrated male pigs (mixed pen). Observations was performed through video-recording 12 h per day, 1 day per week, for 4 consecutive weeks. The number of TIM events (counts) as well as the identity of the performer and the receiver of TIM were recorded. The results showed that the level of TIM activity in the single-gender pens was significantly lower than in the mixed pen (P<0.05). In the mixed pen, TIM tended to be more directed towards the opposite gender and female pigs tended to perform more TIM than the males. Finally, the frequency of TIM increased significantly with age in all three pens (P<0.01).     

Factors Affecting the Glucose Response to Insulin Injection in Mares: Epinephrine, Short- and Long-Term Prior Feed Intake, Cinnamon Extract, and Omega-3 Fatty Acid Supplementation

Five experiments were conducted with mares to better define factors that might affect the assessment of insulin sensitivity via direct insulin injection, and to then apply this method of assessing insulin sensitivity to trials which tested two potential supplements for improving poor insulin sensitivity in horses. The experiments assessed the effects of the following: (1) previous administration of epinephrine, (2) overnight feed deprivation versus hay or pasture consumption, (3) 10-day acclimatization to hay in a dry lot versus pasture grazing, (4) cinnamon extract supplementation, and (5) fish oil supplementation on insulin sensitivity. Mares of known high and low insulin sensitivities were used in the first three experiments, whereas mares with low insulin sensitivities were used in the supplement trials. Epinephrine administration increased blood glucose concentrations (P < .05) and prevented the insulin-induced decrease in blood glucose concentrations in both sensitive and insensitive mares. Overnight feed deprivation decreased (P < .06) insulin sensitivity relative to overnight ad libitum access to hay, and both regimens resulted in reduced insulin sensitivity relative to overnight pasture availability; sensitive and insensitive mares responded similarly except when kept on pasture (P = .0854). Ten days of hay consumption in a dry lot reduced (P < .05) insulin sensitivity in insensitive mares, but not in sensitive mares, relative to pasture grazing. Supplementation with cinnamon extract or fish oil had no effect on insulin sensitivity of mares with known low insulin sensitivity under the conditions of these experiments.