Nocturnal variation of prolactin secretion in the Mouflon (Ovis gmelini musimon) and domestic sheep (Ovis aries): seasonal changes

Seasonal changes in nocturnal prolactin secretion and their relationship with melatonin secretion were monitored in wild (Mouflon, Ovis gmelini musimon) and domesticated sheep (breed Manchega, Ovis aries). Two groups of eleven adult females each, were maintained outdoors under natural photoperiod. Plasma concentrations of prolactin and melatonin were determined during the summer and winter solstices and the autumn and spring equinoxes. Blood samples were collected every 3h during the night hours, and 1h before and after the onset of darkness and sunrise. Maximum mean plasma concentrations of prolactin during the dark-phase in Mouflons were observed in the summer solstice, (P<0.001) and in the summer solstice and spring equinox in Manchega ewes (P<0.001). Mean plasma concentrations of prolactin were higher in the wild species (P<0.001) during the summer solstice. In contrast, during the spring equinox, mean levels of prolactin were higher in Manchega ewes than in Mouflons (P<0.05). Plasma prolactin concentrations showed a nocturnal rhythm in both breeds, with seasonal variations (P<0.001). The increase in plasma melatonin levels during the first hour after sunset was accompanied to increasing concentrations of PRL 1h after the onset of darkness, only in the autumn and spring equinox for the Mouflon, and in the summer solstice and spring equinox for the Manchega ewes. In Mouflons, the fall of plasma PRL concentrations about the middle dark-phase in all the periods studied, coincided with high levels of melatonin. A similar relation was observed in Manchega ewes only in the winter solstice and spring equinox. The current study shows that the nocturnal rhythm of prolactin secretion exhibits seasonal variation; differences in the patterns of prolactin secretion between Mouflon and Manchega sheep are taken to represent the effects of genotype.     

Spread of Mycobacterium avium subsp. paratuberculosis Through Soil and Grass on a Mouflon (Ovis aries) Pasture

The aims of this study were to describe spatial contamination of the environment on a mouflon pasture, as well as to assess the contamination of grass and roots after surface contamination and in depth contamination with feces and buried tissues from animals infected with Mycobacterium avium subsp. paratuberculosis (M. a. paratuberculosis). Samples of soil, roots, and aerial parts of plants were collected from different locations inside the mouflon pasture, and one control sample site was chosen outside the area where the animals are living. M. a. paratuberculosis DNA was present in all the examined sites and was more often detected in roots than in soil. DNA was detected at up to 80 cm of depth and was spatially more widespread than the initial hypothesis of M. a. paratuberculosis leaching vertically into deeper layers of soil. This study broadens our knowledge of the spread and persistence of M. a. paratuberculosis in an environment with highly infected animals.     

Interspecific transfer of IVM IVF-derived red sheep (Ovis orientalis gmelini ) embryos to domestic sheep (Ovis aries )

Two embryo production methodologies were investigated to generate Red sheep embryos for use in an interspecific embryo transfer program. In Experiment 1, 4 multiparous female Red sheep (Ovis orientalis gmelini ) were implanted with CIDR type G devices for 11 d. Forty-eight hours prior to CIDR removal, a total of 22.5 mg bid of FSH-P was administered over a 3-d period. Laparoscopic embryo collection was performed 5 d post breeding, and embryos were transferred to domestic recipient ewes (Ovis aries and Ovis orientalis musimon ). In Experiment 2, 7 nulliparous female Red sheep were implanted with CIDR devices and injected with 200 IU of PMSG and 25 mg of FSH-P on the 8th day of implant insertion. At 60 to 70 h post PMSG/FSH-P treatment, follicular oocytes were aspirated laparoscopically. The recovered oocytes were matured in M199 (with fetal calf serum, FSH, LH, penicillin and streptomycin) at 39 degrees C in a humidified atmosphere containing 5% CO(2). At 24 h oocytes were fertilized with frozen-thawed semen at a concentration of 1.6 x 10(6) sperm/ml. The ova/embryos were placed in CR2 or BOEC culture medium at 20-22 h post IVF. Following 3 to 4 d in culture, embryos were transferred laparoscopically to the uterine horn of synchronized recipients. In Experiment 1, 4 embryos and 6 UFO were collected from 2 embryo donors, respectively. Two embryos were transferred with the aid of a laparoscope to each of 2 Rambouillet recipients, one of which gave birth to a healthy Red sheep lamb at 158 d of gestation. In Experiment2, a total of 62 oocytes was collected from 7 oocyte donors; 16 developed to the 16- to 32-cell stage and were transferred to 8 recipients. Three of these IVM-IVF embryos were transferred laparoscopically to 2 Mouflon recipients, resulting in no pregnancies. Thirteen IVM-IVF embryos were transferred to 6 Rambouillet recipients. Each of these gave birth to a single healthy Red sheep lamb. Gestation lengths of the 3 IVM-IVF lambs ranged from 152 to 162 d. This research demonstrates that when using compatible species IVM-IVF technology in conjunction with interspecific ET can lead to the production of live offspring and can be used to propagate exotic ovine species.     

Interspecific embryo transfer from mouflon (Ovis gmelini musimon) to domestic Corriedale sheep in Argentina

An interspecific embryo transfer program was conducted for genetic improvement and increasing the number of offspring from a flock of mouflon sheep in Argentina. The female donor mouflons were divided into three groups, G1 (n=5), G2 (n=4) and G3 (n=5). The total NIH-FSH-P1 dose given to each donor on the superovulatory treatment was 260, 200 and 160 mg for G1, G2 and G3, respectively. The mouflons in G3 were maidens, while the others were multiparous. Domestic Corriedale ewes (n=60) were synchronized and used as recipients. The embryo recovery and transfer was performed by a surgical method. Mouflons (n=13) responded to the superovulatory treatment with an average of 9.1+/-2.8 ovulations. A low incidence of early luteal regression was found (1 out of 14 donors). Embryo recovery rates were 60, 31 and 76% in groups G1, G2 and G3, respectively. The percentage of transferable embryos obtained in G1 and in G2 exceeded 80%. None of the embryos obtained from G3 were of transferable quality. In G1, 25 transferable embryos were recovered and transferred to 13 recipients, resulting in a pregnancy rate of 76.9% (10/13). In G2, 10 embryos were transferred to 5 recipients, resulting in a 60% pregnancy rate (3/5). Lambing rate was 60% (15/25) and 30% (3/10) for G1 and G2, respectively. Thirteen lambs were born to the 14 donors following natural service after the embryo recoveries. This study demonstrates that the application of IET technology would have great reproductive impact, especially when the donor mouflon hinds are selected according to age and reproductive history.     

Listeric Septicaemia in Sheep Associated with Tick-Borne Fever (Ehrlichiosis Ovis)

Sheep is apparently fairly resistant against infections with Listeria monocytogenes (Lm). Grønstøl (unpublished) found that a high proportion of healthy sheep are carriers of Lm. In such animals Lm may cause clinical disease when resistance is lowered. Tick-borne fever (TBF) is known to reduce the resistance against several infections (Øverås 1972). This report describes listeric septicaemia associated with TBF.     

Seasonal changes in ovulatory activity, plasma prolactin, and melatonin concentrations, in mouflon (Ovis gmelini musimon) and Manchega (Ovis aries) ewes

Seasonal changes in ovulatory activity, plasma prolactin and melatonin concentrations were monitored in a wild (Mouflon) and a domesticated (Manchega) breed of sheep, both originating and living under similar latitudes (40 degrees N). Mouflons express ovarian cycles significantly later than Manchega ewes (October vs. July, P < 0.001); however, they ended cycling one month later than Manchegas (April vs. March, P < 0.05). While prolactin concentrations were high when Manchega ewes started to cycle, they were at their lowest concentrations when Mouflons started cycling. Overall, mean prolactin concentrations were higher (P < 0.001) in Mouflons than Manchegas throughout most of the year. Within the limits of sampling frequency, the duration of melatonin secretion was similar in both groups during the solstice and equinox periods; however, the amplitude was lower (P < 0.01) in Mouflons than Manchegas during the solstice periods. The significant breed differences in the seasonal hormonal changes may be attributed to a genetic influence in the endocrine responses to the same photoperiodic cues.     

Interactions and associations between age and sex classes in mouflon sheep (Ovis gmelini) during winter

The fact that sexual segregation can occur in wild ruminants independently of sex-related differences in habitat use suggests that it results at least partly from social mechanisms. One of the simplest mechanisms which can be hypothesised is that individuals avoid the congener classes which frequently try to interact with them (be these interactions 'agonistic' or 'sexual', since courtship behaviour components typically induce withdrawal when performed outside the rut). The aim of the present study was to test, in mouflon sheep (Ovis gmelini), whether the age-sex classes which exchange frequent interactions on meeting occur rarely inside the same groups. Observations were made during winter, on a small population in Germany. Interactions were recorded at an attractive site where all age-sex classes met daily. Foot transects were conducted in parallel over the whole study area in order to determine group composition. As expected, adults of different sexes exchanged frequent interactions at the attractive site and were rarely found in the same groups under free-ranging conditions, while adult females, who interacted little with one another, were quite frequently associated. However, adult males simultaneously exhibited the highest rate of interaction at the attractive site and the highest frequency of association under free-ranging conditions. Unlike female-female and male-female pairs, in which interactions with a clear initiator and a clear recipient predominated, male-male pairs exchanged often spectacular but 'symmetrical' interactions (during which the two individuals behaved in the same way). The hypothesis that sexual segregation results from the avoidance of the congener classes which frequently engage interactions only holds for females. Adult rams interact frequently and seek companions with whom symmetrical interactions can be performed.     

Exclusion Performance in Dwarf Goats (Capra aegagrus hircus) and Sheep (Ovis orientalis aries)

Using a comparative approach, we investigated the ability of dwarf goats and sheep to use direct and indirect information about the location of a food reward in an object-choice task. Subjects had to choose between two cups with only one covering a reward. Before making a choice, subjects received information about the baited (direct information) or non-baited cup (indirect information). Both goats and sheep were able to use direct information (presence of food) in the object choice task. After controlling for local enhancement, we found that goats rather than sheep were able to use indirect information (i.e., the absence of food) to find a reward. The actual test setup could not clarify whether individual goats were able to inferentially reason about the content of the baited cup when only shown the content of the non-baited cup or if they simply avoided the empty cup in that situation. As browsing species, feral and wild goats exhibit highly selective feeding behaviour compared to the rather unselective grazing sheep. The potential influence of this species-specific foraging flexibility of goats and sheep for using direct and indirect information to find a food reward is discussed in relation to a higher aversion to losses in food acquisition in goats compared to sheep.     

Epidemiological study of the intestinal helminths of wild boar (Sus scrofa) and mouflon (Ovis gmelini musimon) in central Italy

Since 1995 the population of wild ungulates increased significantly in the "Parco provinciale dei Monti Livornesi" (Livorno, Tuscany, Central Italy). We studied the intestinal macroparasites of two hosts, the wild boar (Sus scrofa) and the mouflon (Ovis gmelini musimon). In the case of wild boars we found a dominant parasite species, Globocephalus urosubulatus. For this parasite the frequency distribution of the number of parasites per host agrees with a negative binomial distribution. There is not a significant correlation between the age of the animals and the parasitosis. Furthermore the mean parasite burden of male and female wild boars does not differ significantly. In the case of mouflons we found a dominant parasite species Nematodirus filicollis with Trichuris ovis as codominant species.     

绵羊EGFR基因的克隆、表达及序列分析

表皮生长因子受体(epidermal growth factor receptor,EGFR)是酪氨酸激酶受体家族成员之一,不仅参与细胞增殖、生长和凋亡等多种生命活动,也可调节哺乳动物的乳腺发育及泌乳维持,但对绵羊EGFR基因的序列特征及组织表达情况鲜有报道.本试验以高泌乳量的小尾寒羊(泌乳高峰期和空怀期)及低泌乳量的甘肃高山细毛羊(泌乳高峰期)母羊为研究对象,利用RT-PCR、克隆及测序技术获得绵羊EGFR基因完整的CDS区,分析了 EGFR蛋白的结构特征及理化性质,利用RT-qPCR技术研究了基因的组织表达情况.结果表明,绵羊EGFR基因CDS区全长为3 627 bp,编码1 208个氨基酸.绵羊EGFR的氨基酸序列在各物种间较保守,与黄牛EGFR的氨基酸序列同源性最高.EGFR为跨膜蛋白,包含111个磷酸化位点,二级结构以α螺旋和无规则卷曲为主.网络互作分析表明EGFR蛋白与肝素结合表皮生长因子(HB-EGF)、表皮调节素(EREG)、双调蛋白(AREG)及生长因子受体结合蛋白2(GRB2)结合发挥作用.EGFR主要参与MAPK,PI3K/AKT,JAK/STAT及Wnt信号通路,从而参与了动物的乳腺发育及泌乳功能的调节.RT-qPCR结果表明,绵羊EGFR基因的表达具有组织特异性、时空特异性和品种特异性.该基因在所研究的8个组织中均表达,但在肾脏、卵巢、肝脏、乳腺和肺脏组织中的表达量较高;在小尾寒羊的乳腺组织中,该基因在空怀期的表达量显著高于泌乳高峰期的(P＜0.05);在泌乳高峰期的乳腺组织中,该基因在小尾寒羊中的表达量高于甘肃高山细毛羊的.本试验为深入研究绵羊EGFR基因的泌乳生物学功能提供了基础数据.     

Agonistic and proximity patterns in enclosed mouflon (Ovis gmelini) ewes in relation to age, reproductive status and kinship

Agonistic and proximity patterns of mouflon sheep (Ovis gmelini) were studied in a group of enclosed females during two lambing periods. A non-random linear-tending hierarchy almost stable over the 2-years was found. Age was correlated to social rank and to the distribution of agonistic acts by females. The rank of the yearling females was linked to the rank of their mothers. The age of the animal and the degree of relatedness with its congeners appeared as main determinants of the proximity patterns of ewes. Strong associations between closely related females (especially mothers and daughters), brought out the existence of a familial structure in mouflon. Otherwise, we found a strong inter-attraction between yearlings, which received a large number of aggressions from older females. That revealed peer grouping superimposed on familial structures. Age also seemed to influence ‘sociality’ of females, older females tending to associate less with conspecifics than younger ones.     

Genotype and Phenotype of Echinococcus granulosus Derived from Wild Sheep (Ovis orientalis) in Iran

The aim of the present study is to determine the characteristics of genotype and phenotype of Echinococcus granulosus derived from wild sheep and to compare them with the strains of E. granulosus sensu stricto (sheep-dog) and E. granulosus camel strain (camel-dog) in Iran. In Khojir National Park, near Tehran, Iran, a fertile hydatid cyst was recently found in the liver of a dead wild sheep (Ovis orientalis). The number of protoscolices (n=6,000) proved enough for an experimental infection in a dog. The characteristics of large and small hooks of metacestode were statistically determined as the sensu stricto strain but not the camel strain (P=0.5). To determine E. granulosus genotype, 20 adult worms of this type were collected from the infected dog. The second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA (rDNA) and cytochrome c oxidase 1 subunit (COX1) of the mitochondrial DNA were amplified from individual adult worm by PCR. Subsequently, the PCR product was sequenced by Sanger method. The lengths of ITS2 and COX1 sequences were 378 and 857 bp, respectively, for all the sequenced samples. The amplified DNA sequences from both ribosomal and mitochondrial genes were highly similar (99% and 98%, respectively) to that of the ovine strain in the GenBank database. The results of the present study indicate that the morpho-molecular features and characteristics of E. granulosus in the Iranian wild sheep are the same as those of the sheep-dog E. granulosus sensu stricto strain.     

Weaning Conflict in Desert and Mountain Bighorn Sheep (Ovis canadensis): An Ecological Interpretation

Field data on weaning behavior in bighorn sheep (Ovis canadensis) were collected from populations in British Columbia, southern California, and one transplanted from the original B.C. study site to eastern Oregon. These areas were designated mountain, desert, and transplant, respectively. Seasons that were energetically stressful to lactating ewes were predicted. Summers were implicated for desert ewes; winters for ewes in colder and more seasonal northern environments. Although the temporal distribution of milk available to lambs varied between the three study populations, ewes generally weaned their lambs prior to the onset of the predicted stressful periods. In the desert, weaning occurred more abruptly than it did in the two more northern populations. The evolution of weaning strategies is discussed in subspecies of bighorn sheep based on proximate and ultimate factors.     

In-Depth Characterization of Sheep (Ovis aries) Milk Whey Proteome and Comparison with Cow (Bos taurus)

An in-depth proteomic study of sheep milk whey is reported and compared to the data available in the literature for the cow whey proteome. A combinatorial peptide ligand library kit (ProteoMiner) was used to normalize protein abundance in the sheep whey proteome followed by an in-gel digest of a 1D-PAGE display and an in-solution digestion followed by OFFGEL isoelectric focusing fractionation. The peptide fractions obtained were then analyzed by LC-MS/MS. This enabled identification of 669 proteins in sheep whey that, to our knowledge, is the largest inventory of sheep whey proteins identified to date. A comprehensive list of cow whey proteins currently available in the literature (783 proteins from unique genes) was assembled and compared to the sheep whey proteome data obtained in this study (606 proteins from unique genes). This comparison revealed that while the 233 proteins shared by the two species were significantly enriched for immune and inflammatory responses in gene ontology analysis, proteins only found in sheep whey in this study were identified that take part in both cellular development and immune responses, whereas proteins only found in cow whey in this study were identified to be associated with metabolism and cellular growth.     

巴什拜羊骨骼肌卫星细胞分离培养及诱导分化

为了获得巴什拜羊骨骼肌卫星细胞,本研究采集出生1日龄巴什拜羔羊后肢骨骼肌组织,采用两步酶消化法结合差速贴壁法分离纯化巴什拜羊骨骼肌卫星细胞,并对分离获得的骨骼肌卫星细胞进行了鉴定、传代培养及诱导分化等研究。结果表明,本研究采用的分离纯化方法可以高效获得巴什拜羊骨骼肌卫星细胞,RT-PCR检测结果表明骨骼肌卫星细胞标志性基因pax7、Myf5、MyoD、desmin和c-Met均呈阳性表达。获得的骨骼肌卫星细胞具有较强的增殖能力,连续传代12代,细胞的形态仍保持正常,且细胞的克隆形成率仍保持在50%以上,但是当细胞传代至第18代时,逐渐表现出较为明显的衰退。细胞的生长符合典型的"S"型生长曲线,且第2代和第8代细胞的生长曲线没有明显的差异,至第14代时细胞的增殖速度逐渐降低。采用低浓度马血清培养体系,可成功诱导巴什拜羊骨骼肌卫星细胞向肌管方向分化,诱导培养至第5天时,骨骼肌卫星细胞分化标志基因MyHC呈阳性表达。由此得出结论,本研究采用的骨骼肌卫星细胞分离纯化体系高效、可靠,可以满足较高纯度巴什拜羊骨骼肌卫星细胞的分离培养。