排序方式： 共有57条查询结果，搜索用时 62 毫秒
21.
Kollmann MT Locher M Hirche F Eder K Meyer HH Bruckmaier RM 《Domestic animal endocrinology》2008,34(1):14-24
This study was conducted to investigate the effects of rumen-protected tryptophan (125 g tryptophan per day) in heifers and dairy cows. Blood samples from dairy cows and heifers were collected for 24h in 3-h intervals on the day before tryptophan supplementation, on day 2, 5 and 7 of tryptophan supplementation, and in heifers additionally on d 14 after tryptophan supplementation was ceased. Plasma tryptophan, melatonin, serotonin, and prolactin concentrations were determined. Tryptophan plasma concentrations on d 5 were augmented at day (11:00 h) and nighttime (02:00 h), (P<0.05) in response to tryptophan supplementation in heifers by 119% and in dairy cows by 47%, respectively, as compared with d 0. Melatonin increased (P<0.05) in response to tryptophan supplementation in heifers, but not in cows. The effect of tryptophan supplementation on plasma tryptophan and melatonin was reversible as demonstrated in heifers on d 14 after cessation of tryptophan supplementation. Serotonin and prolactin in plasma did not respond to tryptophan supplementation. However, milk yield during morning milking increased significantly in tryptophan supplemented cows on d 1, 3 and 4 as compared to the day before tryptophan supplementation. Additional blood samples were taken during afternoon milking in cows at 1-min intervals for the analyses of oxytocin and prolactin on the day before the start and on d 7 of tryptophan supplementation. Milk flow curves were recorded during milking. No effect of tryptophan supplementation on the milking related release of oxytocin and prolactin and on any characteristic of milk flow was observed. In conclusion, tryptophan supplementation caused increased plasma tryptophan in cows and heifers and plasma melatonin in heifers. However, plasma serotonin, prolactin and oxytocin release in cows remained unchanged by tryptophan supplementation. Milk yield at morning milking increased slightly and transiently in response to tryptophan supplementation. 相似文献
22.
【目的】研究催产素(OXT)和苯甲酸雌二醇(E2)对淋巴细胞增殖的影响,探讨OXT和E2的相互作用机制。【方法】分别以静息和Con A刺激下的雌性绵羊外周血淋巴细胞为研究对象,用不同质量浓度(低质量浓度(OXT 10ng/mL,E2 50pg/mL)、中质量浓度(OXT 100ng/mL,E2 500pg/mL)和高质量浓度(OXT 1 000ng/mL,E25 000pg/mL))和处理方式(单用、联用(二者同时加入、E2预处理12h后加OXT、OXT预处理12h后加E2))的OXT、E2处理细胞,用MTT试验检测淋巴细胞的增殖水平,评估雌激素、催产素的相互作用方式。【结果】OXT对活化和静息状态的淋巴细胞均有抑制作用,且呈剂量依赖性。低质量浓度的E2可促进Con A刺激的T淋巴细胞增殖,但对静息状态的淋巴细胞无明显影响;随E2质量浓度的增加,高质量浓度的E2对不同状态的淋巴细胞增殖均有抑制作用。低质量浓度OXT和E2联用条件下,Con A活化的T淋巴细胞的刺激指数(SI)值介于2种激素单独作用之间;静息状态下的淋巴细胞增殖明显受到抑制,该抑制作用均强于2种激素单独作用;用生理浓度的OXT(10ng/mL)和E2(50pg/mL)对活化状态的淋巴细胞分别进行先后处理,对不同状态淋巴细胞增殖的影响偏向于后加入的激素的作用。【结论】高质量浓度的E2可抑制静息和Con A刺激活化的淋巴细胞的增殖,低质量浓度的E2对Con A刺激活化的淋巴细胞增殖有促进作用,而OXT抑制淋巴细胞的增殖。高质量浓度OXT和E2联用,在静息状态的淋巴细胞上体现了协同作用;低质量浓度OXT和E2联用,在活化状态的淋巴细胞上体现了相互颉颃和"利他作用"2种作用模式,显示了二者相互作用方式的多样性。 相似文献
23.
The experiment was aimed to evaluate the stability of oxytocin in osmotic pump (ALZET®) at 39.1℃. The experiment was divided into 3 groups, i.e. the osmotic pump group, microcentrifugal tube group and control group. The control group remained frozen at -80℃, the other two groups were incubated in 39.1℃ incubator, and the samples were collected at different time points. All samples were analyzed by ultra-performance liquid chromatography tandem quadrupole/flight time mass spectrometry (UPLC-Q-TOF MS) method. The oxidation process of oxytocin in osmotic pump at 39.1℃ was analyzed by comparing the peak area of main oxidized products extracted ion chromatogram. The results showed that the degree of oxidation increased with time in osmotic pump and microcentrifugal tube at 39.1℃, and there was no significant difference between the two groups (P >0.05). The percentage of oxytocin prototype of samples which collected at different time points of osmotic pump group and microcentrifugal tube group versus control group were 83.6% to 117.8% and 83.2% to 116.2%, respectively, suggested that the trials involved in the osmotic pump implantation of oxytocin in sheep need to consider the effect of content changes caused by oxytocin oxidation on the test results. 相似文献
24.
Kaori MURATA Miho NAGASAWA Tatsushi ONAKA Ken-ichi TAKEYAMA Takefumi KIKUSUI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(3):478
The biological and psychological significance of oxytocin is increasingly recognized; however, reliable assays of oxytocin in biological samples have not been developed. We raised a new oxytocin polyclonal rabbit antibody against synthetic oxytocin. The affinity of antibodies to oxytocin was examined by a radio-immunoassay and compared with that of a previously validated antibody. One antibody showed affinity for oxytocin in the radio-immunoassay. We developed a solid-phase ELISA for oxytocin using this antibody and compared it with existing methods. The newly developed ELISA showed comparable results using urine samples but not using serum samples. These results indicate that the new ELISA is useful for urinary oxytocin; further modifications, such as different extraction methods, are needed for its application to serum oxytocin. 相似文献
25.
Shuli HUANG Guoliang LI Yongliang PAN Mingjing SONG Jidong ZHAO Xinrong WAN Charles J. KREBS Zuoxin WANG Wenxuan HAN Zhibin ZHANG 《Integrative zoology》2021,16(2):149-159
It is known that social stress could alter oxytocin (OT) and arginine-vasopressin (AVP) expression in specific regions of brains which regulate the aggressive behavior of small rodents, but the effects of density-induced social stress are still unknown. Brandt's voles (Lasiopodomys brandtii) are small herbivores in the grassland of China, but the underlying neurological mechanism of population regulation is still unknown. We tested the effects of housing density of Brandt's voles on OT/AVP system with physical contact (allowing aggression) and without physical contact (not allowing aggression) under laboratory conditions. Then, we tested the effects of paired-aggression (no density effect) of Brandt's voles on OT/AVP system under laboratory conditions. We hypothesized that high density would increase aggression among animals which would then increase AVP but reduce OT in brains of animals. Our results showed that high housing density induced more aggressive behavior. We found high-density-induced social stress (with or without physical contact) and direct aggression significantly increased expression of mRNA and protein of AVP and its receptor, but decreased expression of mRNA and protein of OT and its receptor in specific brain regions of voles. The results suggest that density-dependent change of OT/AVP systems may play a significant role in the population regulation of small rodents by altering density-dependent aggressive behavior. 相似文献
26.
Saeed Murtaza Abdul Sattar Nasim Ahmad Muhammad Jamil Ahmad Saleem Akhtar Ejaz Ahmad Tanveer Ahmad Talha Omer 《Reproduction in domestic animals》2021,56(11):1369-1376
Based on different surveys, dairy farmers are concerned about extensive use of exogenous oxytocin in buffaloes, which is being held responsible for reproductive problems including irregular oestrous cycle and delayed ovulation. For these concerns, effects of oxytocin injection on postpartum follicular dynamics, postpartum oestrous interval (PEI), oestrous length, the interval from onset of estrus to ovulation and blood progesterone (P4) were studied in Nili-Ravi buffaloes. For this purpose, 23 animals within 1 week after calving were randomly divided into three groups: without oxytocin (CON; n = 7), 10 i.u. oxytocin (LOW; n = 8), 30 i.u. oxytocin – (HIGH; n = 8) and used to record the PEI for the study period of 154 days. At subsequent estrus, three buffaloes from each group (not served) were selected randomly to monitor two cycles for 6 weeks. Transrectal ultrasonography was performed to evaluate follicular and corpus luteum (CL) development, and blood sampling was done for progesterone (P4) analysis. These results revealed that postpartum oestrous interval (PEI) decreased significantly in oxytocin-treated groups. The number of small, medium and total follicles on the left ovary was significantly higher in the HIGH group. However, an overall number of small and total follicles on both right and left ovaries was significantly higher in CON and HIGH groups. On the other hand, there was no difference in the number of follicles on the right ovary among all treatment groups. The same was true for the size of pre-ovulatory follicles, CL, P4 concentrations and oestrous cycle length. The intervals from onset of estrus to ovulation and from standing estrus to ovulation were increased considerably in the HIGH group. It is concluded that exogenous oxytocin administration resulted in the shortening of PEI but triggered a delay in ovulation. Moreover, a higher dose of oxytocin could stimulate the growth of small, medium, and total follicles in postpartum Nili-Ravi buffaloes. 相似文献
27.
To examine the influence of postnatal oxytocin (OXT) on behavioral development, we examined individual variations in basal OXT and suckling‐induced changes in OXT, and their relationship with emotional traits during development. Blood OXT were measured in 20 Holstein heifer calves at 1 (wk1), 2 (wk2), and 6 weeks of age (wk6). The relationships of OXT variables with principal component scores in the open‐field tests at wk2 and 2 months and the number of flinch, step and kick responses during first artificial insemination and machine milking were analyzed. The basal OXT showed individual variability and significantly correlated (wk1 vs. wk2: r = 0.753, P < 0.001; wk1 vs. wk6: r = 0.499, P < 0.05; wk2 vs. wk6: r = 0.476, P < 0.05). The personality traits reflecting a response in the form of escape from novel environments in the open‐field test at wk2 were inversely correlated with basal OXT at wk1 (rs = ?0.640, P < 0.01) and wk2 (rs = ?0.447, P < 0.05). However, none of the behavioral variables after 2 months correlated with OXT. These findings suggest that, postnatal OXT might be related to behavioral characteristics in novel environments only during the early stages of life. 相似文献
28.
29.
30.
Xiaoyu Lu Yiyong Liu Jing Zhang Xinglong Wu Xiangyun Li 《Reproduction in domestic animals》2021,56(6):942-947
It is probable that reduced pregnancy rates in ewes after fixed time artificial insemination (FTAI) is attributable, in part, to the reduced number of normal spermatozoa that colonize the oviduct. Administration of oxytocin stimulates both cervical dilation and uterine/oviductal contractility. The hypothesis that oxytocin can enhance sperm transport into the uteri and the oviducts, and thereby increase pregnancy rates, was tested in the present study. Oestrus was synchronized in 199 multiparous Kazak ewes using intravaginal flurogestone-impregnated sponge. The sponge was left in the vagina for 12 days followed with an injection of 330 IU of eCG at sponge removal. Each ewe was intracervically inseminated twice at 50 hr and 62 hr after the removal of sponges using an insemination catheter containing 0.25 ml of diluted semen. Semen was collected from seven Texel rams and all the ejaculates were pooled and diluted in ultra-high temperature-treated commercial skimmed milk without (Control group, 0.05 ml of saline per mL milk, n = 144) or with oxytocin supplement (Oxytocin group, 0.5 U of oxytocin per ml milk, n = 55). Pregnancy status was determined by transabdominal ultrasound examination 45 days after insemination. Lambing performance was recorded at delivery. Significant differences were observed between the Oxytocin group and the Control group in terms of the pregnancy rate and the fecundity rate (85.5% and 92.7% versus 68.8% and 72.9%, respectively). In conclusion, low dose oxytocin supplementation of semen extender significantly increased pregnancy and fecundity rates in oestrus-synchronized Kazak ewes after FTAI. 相似文献