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1.
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.  相似文献   

2.
OBJECTIVE: To evaluate the effects of trimethoprim-sulfamethoxazole and pyrimethamine treatment on various measures of reproductive function in healthy pony stallions. DESIGN: Randomized complete block study. ANIMALS: 12 healthy, mature pony stallions. PROCEDURE: Stallions were assigned to treatment and control groups balanced for age and various characteristics of reproductive function. The treated group received trimethoprim-sulfamethoxazole and pyrimethamine for 90 days during summer and fall; the control group was not treated. Semen characteristics, sexual behavior, testicular volume, and sperm production efficiency were evaluated before treatment started and at 30-day intervals until 60 days after treatment ended. RESULTS: Effects of treatment were not detected for semen characteristics, testicular volume, sperm production efficiency, libido, erection, and quantitative measures of ejaculatory efficiency. At 30, 60, and 90 days, 4 of 6 treated stallions had unsteadiness upon mounting, clumsy or weak thrusting, failure to flex the back, and thready or inapparent ejaculatory pulses that resulted in dribbling of semen rather than forceful expulsion. CONCLUSIONS AND CLINICAL RELEVANCE: Although treatment with trimethoprim-sulfamethoxazole and pyrimethamine may not affect semen quality, testicular volume, sperm production efficiency, erection, or libido of healthy stallions, treatment may induce changes in copulatory form and agility and alter the pattern and strength of ejaculation. Stallions that develop neurologic signs during treatment should be used with caution for breeding.  相似文献   

3.
Mature and healthy male house rats, Rattus rattus (n= 160) were fed on bait (cracked wheat: powdered sugar, 98:2) containing different concentrations of triptolide (0.1, 0.05, 0.025 and 0%) for 7 and 14 days in no‐choice and bi‐choice feeding tests in the laboratory. The objective of the study was to record the antifertility affects of triptolide after 30 and 60 days of termination of treatment. Results revealed no significant effect of triptolide treatment on weights of testis, epididymis, seminal vesicles and prostate gland of rats. Overall, sperm motility, live sperm count, sperm density and sperm morphology in the cauda epididymal fluid were found to differ significantly (P≤ 0.05) between untreated and treated groups of rats. The major effect of triptolide on sperm morphology was in the form of sperm head tail separation, which was up to 56.0% in rats treated for 14 days in no‐choice and autopsied after 30 days. A significant effect (P≤ 0.05) of triptolide treatment was observed on the histomorphology of the testis, which included a dose‐dependent decrease in diameter of seminiferous tubules, thickness of germinal epithelium and numbers of various spermatogenic cells. Cell associations in the seminiferous epithelial cycle were poorly developed in rats ingesting medium (4.7–5.1 mg/100 g bw) and high doses (6.9–7.2 mg/100 g bw) of triptolide than rats ingesting low doses (1.8–2.3 mg/100 g bw) and untreated rats. The cell stages affected had not recovered fully within the 60 day period following triptolide withdrawal. The present study suggests the potential of triptolide in reproductive management of Rattus rattus.  相似文献   

4.
The present experiments were done to determine the effectiveness of a non-specific nitric oxide synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME), on oxidative stress parameters induced by aluminium chloride (AlCl3) intrahippocampal injections in Wistar rats. Animals were sacrificed 3 h and 30 d after treatments, heads were immediately frozen in liquid nitrogen and forebrain cortices were removed. Crude mitochondrial fraction preparations of forebrain cortices were used for the biochemical analyses: nitrite levels, superoxide production, malondialdehyde concentrations, superoxide dismutase (SOD) activities and reduced glutathione contents. AlCl3 injection resulted in increased nitrite concentrations, superoxide anion production, malondialdehyde concentrations and reduced glutathione contents in the forebrain cortex, suggesting that AlCl3 exposure promoted oxidative stress in this brain structure. The biochemical changes observed in neuronal tissues showed that aluminium acted as a pro-oxidant. However, the non-specific nitric oxide synthase (NOS) inhibitor, L-NAME, exerted anti-oxidant actions in AlCl3-treated animals. These results revealed that NO-mediated neurotoxicity due to intrahippocampal AlCl3 injection spread temporally and spatially to the forebrain cortex, and suggested a potentially neuroprotective effect for L-NAME.  相似文献   

5.
The objective of this study was to determine the impact of ginger and/or thyme aqueous extracts administration on the growth rate, caecum activity, reproductive performance and semen quality of rabbits. A total of 24 V‐line male rabbits at the age of 12 weeks were divided randomly into four equal groups (6/each) until 24 weeks of age. Treatments were as follows: drinking fresh water and served as control (G1); drinking water supplemented with 100 mg/kg b. wt. of ginger aqueous extract (G2); drinking water supplemented with 50 mg/kg b. wt. of thyme aqueous extract (G3); drinking water supplemented with 100 mg/kg b. wt. of ginger aqueous extract plus 50 mg/kg b. wt. of thyme aqueous extract (G4). Administration of aqueous thyme extract with 50 mg/kg b. wt. improved (p < 0.001) feed intake and growth performance compared to control. The highest average daily gain (p < 0.001) was found for G3 rabbits followed by G4, G2 and G1 respectively. While the most efficient feed conversion ratio was found in G4. Group 3 and group 4 had significant (p < 0.05) positive effect on caecum pH, ammonia and TVFAs concentration. Data indicated that treated groups had hastened the age with heavier body weight, larger testicular size and higher testosterone level. Also, most semen characteristics (volume, progressive motility, sperm concentration and normal spermatozoa) were higher in treated groups compared with the control group. Furthermore, gathering of the spermatozoa in the lumen of the seminiferous tubules, expanded epithelial cells stature of the epididymis with stuffed lumens with sperms in treated groups. In conclusion, aqueous extracts of ginger and/or thyme can be used as a growth promoter for improving reproductive performance of V‐line male rabbits.  相似文献   

6.
This study aimed to evaluate three regimes for oestrus and ovulation synchronization in Farafra ewes in the subtropics. During autumn, 43 ewes were assigned to (i) controlled internal drug releasing (CIDR)‐eCG group, treated with CIDR for 12 days and eCG at insert withdrawal, n = 13; (ii) PGF2α‐PGF2α group, treated with two PGF2α injections at 11 days interval, n = 14; and (iii) GnRH‐PGF2α‐GnRH group, treated with GnRH, followed 5 days later with PGF2α and 24 h later with a second GnRH, n = 16. Oestrus‐mating detection was carried out at 4 h intervals starting on day 0 [the day of CIDR withdrawal (CIDR‐eCG group), the day of second PGF2α treatment (PGF2α‐PGF2α group) and the day of PGF2α treatment (GnRH‐PGF2α‐GnRH group)]. Ovarian dynamics was monitored by ultrasound every 12 h beginning on day 0 and continued for 4 days. Blood samples were obtained daily for progesterone (P4) and oestradiol 17β (E2) estimation starting on day 0 and continued for 4 days. The obtained results showed that, oestrus expression, ovulation and conception were greater (p < 0.05) in CIDR‐eCG and PGF2α‐PGF2α groups than in GnRH‐PGF2α‐GnRH group. All ewes of PGF2α‐PGF2α group presented, on day of second PGF2α injection with mature CL (P4 > 2.0 ng/ml), compared to 42.9% in GnRH‐PGF2α‐GnRH group (p = 0.01). The peak of oestrus occurred 32–52, 48–60 and 28–96 h after the end of treatment in CIDR‐eCG, PGF2α‐PGF2α and GnRH‐PGF2α‐GnRH groups, respectively. Ovulation started 48 h after treatment in all groups and extended for 24, 36 and 48 h for CIDR‐eCG, PGF2α‐PGF2α and GnRH‐PGF2α‐GnRH groups, respectively. Results demonstrated that oestrus and ovulation synchronization could be efficiently achieved in Farafra ewes using either CIDR‐eCG or PGF2α‐PGF2α regimes; however, the GnRH‐PGF2α‐GnRH treatment induced a more spread oestrus and ovulation that may make the protocol inadequate for timed artificial insemination.  相似文献   

7.
The study was conducted for a period of 45 days to assess the influence of body condition scoring (BCS) on reproductive efficiency of Malpura rams in terms of sexual behaviour, scrotal measurements, semen attributes and endocrine responses. The rams were randomly divided into three groups as group I (BCS = 2.5; n = 7), group II (BCS = 3.0; n = 7) and group III (BCS = 4.0; n = 7). Apart from grazing for 8 h a day, the rams were provided with concentrate mixture at the rate of 100, 300 and 500 g to groups I, II and III respectively to attain their respective BCS. Under these differential feeding regimes, sexual behaviour scrotal measurements, semen characteristics and endocrine parameters were studied at 15‐days interval. Sexual behaviour, scrotal volume, scrotal circumference, testicular width, testicular length and scrotal skin thickness differed significantly (p < 0.05) between lower BCS group (group I) and higher BCS groups (groups II and III). The semen volume, mass motility and progressive sperm motility were recorded significantly (p < 0.05) higher in group II and lowest in group I. However, the sperm concentration did not differ significantly between the groups. The mean plasma testosterone concentration differed significantly (p < 0.05) between lower BCS group (group I) and higher BCS groups (groups II and III). Circulating plasma hormone concentrations were influenced due to the BCS. Plasma cortisol, T3 and T4 increased as the BCS improved from lower to higher. In conclusion, better reproductive efficiency of rams of moderate BCS (3.0 and 3.5) than rams of lower (2.5) and higher BCS (4.0) indicates the importance of maintaining optimum body condition of breeding rams under hot semi‐arid environment.  相似文献   

8.
The efficiency of treatments for unobserved oestrus and their effect on the reproductive performance of a dairy cattle herd with low oestrous detection rate till 60 days post‐partum (dpp), attributed to the declivous and slippery concrete floor were investigated. The herdsman requested advice in order to improve the mean days open of the herd, but no investments were allowed because a new unit was about to be built. Due to the low oestrus detection rate of the herd, the breeding policy was to inseminate at the first detected post‐partum oestrus. Cows were examined at 20–30 dpp to assess uterine involution, ovarian activity and prevalence of reproductive disorders and, at 60 dpp if no previous oestrus was detected. Each examination included palpation per rectum, ultrasound scanning and collection of a blood sample for plasma progesterone (P4) measurement. Cows with unobserved oestrus till 60 dpp were allocated either to a treatment group (n=139) or to a control group (n=139). Three treatments were used: (a) injection of PGF2α (PG) upon detection of a corpus luteum (CL; n = 30), cows not observed in oestrus being re‐injected 11–12 days later. AI was at oestrus; (b) PRID (n=35) or Crestar (n=74) devices kept in situ for 12 and 9 days, respectively, were associated to an injection of PG and of equine chorionic gonadotrophin (eCG) at device removal. Cows were double‐fixed time‐inseminated at 48 and 72 h after device removal. All treated cows were examined at 48–72 h after treatment to confirm oestrus. The percentage of cows detected in oestrus up to 60 dpp remained unchanged through the trial (35 and 47% for years before intervention: 1994–95; 51 and 48% for years of intervention: 1996–97). In contrast, the oestrous detection rate was high both in treated (93%) and control (100%) cows. This possibly resulted from an improvement in the oestrous detection efficiency of the herd's personnel and from examination of cows at 48–72 h after treatment. Treated and control cows had identical conception rate (CR; 36 and 37%, respectively) and reproductive performance. However, the mean days open of the herd in 1996 was significantly improved in comparison with previous years (mean ± SEM: 134 ± 6, 126 ± 5, 110 ± 4 and 114 ± 5 days, for years 1994, 1995, 1996 and 1997, respectively, p < 0.05, ANOVA ). Conception rate to AI up to 40 dpp was significantly reduced, compared with the period between 60 and 100 dpp but, mean days open were significantly improved in cows inseminated up to 60 dpp, compared with thereafter (p < 0.05).  相似文献   

9.
The objective of this study was to compare the reproductive performance of cows affected by clinical endometritis (CE) following treatment with an intrauterine infusion of 50% dextrose solutions (DEX) and liquid paraffin (LP) as alternative therapies with routine treatments including PGF2α injection and intrauterine infusion of oxytetracycline (OTC). Moreover, the reproductive indices of cows treated with endometritis were compared with those of healthy ones. At postpartum reproductive tract examination (28–35 DIM) in one Iranian dairy farm, cows with CE without any selection were assigned to four groups: (a) OTC, a common treatment in Iran, was administered (5 g) to 396 cows, (b) PGF2α (PG) was injected to 496 cows, (c) dextrose solution (DEX): intrauterine infusion of 50% dextrose solution (200 ml) was done in 427 cows, and (d) liquid paraffin (LP) was administered (100 ml) to 423 cows via intrauterine route. We further assigned 2,233 clinically healthy cows to the control group. The incidence of endometritis was 41.6% in this study. Based on the results of reproductive indices including median days to first AI, days open (DO), first service conception rate, conception rate in 2nd and 3rd services, conception rate in all three services, pregnancy rate < 100 days and pregnancy rate < 200 days, except for median days to first AI in other reproductive indexes, reproductive performance was significantly lower in LP group compared with the healthy cows and other treatment groups (p < 0.05). Except for the first service conception rate and proportion of cows pregnant before 100 days in milk (DIM), there existed no significant difference between the DEX group and the control as far as reproductive performance is concerned (p ≥ 0.05). The first service conception rate was recognizably lower in DEX group compared with OTC and PG (p < 0.05). In conclusion, the use of a non‐antibiotic special solution of dextrose 50% is a good alternative to antibiotic agents concerning the treatment of CE in dairy cows.  相似文献   

10.
Most temperate‐zone animals are seasonal breeders. In a previous study, it was found that light‐induced hormone conversion of thyroxine (T4) prohormone to active 3,5,3′‐triiodothyronine (T3) in the mediobasal hypothalamus regulates photoperiodic response of gonads in Japanese quail. Here the effect of T4 or T3, administered in drinking water, on testicular growth in the Japanese quail kept under short days is shown. Testicular length was significantly increased in birds given T4 at doses of 4, 8 and 10 mg/L, while any dose of T3 had little effect on testicular growth. High doses (8 and 10 mg/L) of T4 and T3 resulted in high mortality and/or reduction of bodyweight. Among all of the treatment, 4 mg/L of T4 was the most effective on photoperiodic testicular growth, which caused little reduction in bodyweight. These data provide a new conventional method for promoting gonadal growth under short days.  相似文献   

11.
The penetration of antimicrobials in pig tonsils is hardly known. The objective of the study was to quantify the tildipirosin (TD) penetration in tonsils. Animals were randomly divided into six groups (control, T1, T2 (1), T2(5), T2(10), and T2(15)) of eight animals. T1 and T2 groups received a dose of 2 and 4 mg of TD/kg bw in one shot (Zuprevo® MSD Animal Health), respectively, and the control group received 2 mL of saline solution. The animals were sacrificed by intravenous administration of pentobarbital sodium 24 h after finishing the treatment for the control, T1, and T2(1) groups, whereas animals of T2(5), T2(10), and T2(15) groups were sacrificed at 5, 10, and 15 days, post‐treatment, respectively. Tonsils and blood samples were taken at necropsy to obtain plasma, and the tildipirosin concentration was determined by high‐performance liquid chromatography with tandem mass spectrometry detection. The concentration in plasma was always significantly lower than in tonsil. Average TD tonsil concentrations increased significantly in a dose‐dependent manner, and the tonsil TD vs. plasma TD concentration ratio was approximately 75 for the doses of 2 and 4 mg of TD/kg bw at 24 h post‐treatment. Moreover, the maximum concentration of tildipirosin in tonsil was observed at 1 day postadministration, and this concentration decreased gradually from this day until 15 days postadministration for the dose of 4 mg of TD/kg bw. Finally, the ratio AUCtonsil/AUCplasma was 97.9, and the T1/2 (h) was clearly higher in tonsil than in plasma.  相似文献   

12.
The plasma kinetic profile of moxidectin (MXD) in ewes during the last third of pregnancy was studied after the subcutaneous dose of 0.2 mg/kg of body weight (bw). Two groups of sheep (n = 7) that were equally balanced in body weight were used. Group I (control) was maintained unmated, while Group II (pregnant) was estrous‐synchronized and mated with fertile rams. Both groups were maintained under similar conditions regarding management and feeding. When the ewes from Group II fulfilled 120 days of pregnancy, both groups were treated with a subcutaneous injection of 0.2 mg of MXD/kg bw. Blood samples were collected at different set times between 1 h and 40 days post‐treatment. After plasma extraction and derivatization, the samples were analyzed using high‐performance liquid chromatography with fluorescence detection. A noncompartmental pharmacokinetic analysis was performed, and the data were compared using Student's t‐test. The mean pharmacokinetic parameters, including Cmax, Tmax, and the area under the concentration–time curve (AUC), were similar for both groups of sheep. The average of elimination half‐life was significantly lower (P = 0.0023) in the pregnant (11.49 ± 2.2 days) vs. the control (17.89 ± 4.84 days) sheep. Similarly, the mean residence time (MRT) for the pregnant group (20.6 ± 3.8 days) was lower (P = 0.037) than that observed in the control group (27.4 ± 9.1 days). It is concluded that pregnancy produces a significant decrease in mean values of half‐life of elimination of MXD, indicating that pregnancy can increase the rate of elimination of the drug reducing their permanence in the body.  相似文献   

13.
In pregnant sheep at 120–130 days of gestational age, a study was undertaken in order to characterize the pharmacokinetics and transplacental exchange of Ivermectin after maternal or fetal intravenous administration. Eight pregnant Suffolk Down sheep of 73.2 ± 3.7 kg body weight (bw) were surgically prepared in order to insert polyvinyl catheters in the fetal femoral artery and vein and amniotic sac. Following 48 h of recovery, the ewes were randomly assigned to two experimental groups. In group 1, (maternal injection) five ewes were treated with an intravenous bolus of 0.2 mg ivermectin/kg bw. In group 2, (fetal injection) three ewes were injected with an intravenous bolus of 1 mg of ivermectin to the fetus through a fetal femoral vein catheter. Maternal and fetal blood and amniotic fluid samples were taken before and after ivermectin administration for a period of 144 h post‐treatment. Samples were analyzed by liquid chromatography (HPLC). A computerized non‐compartmental pharmacokinetic analysis was performed and the results were compared by means of the Student t‐test. The main pharmacokinetic changes observed in the maternal compartment were increases in the volume of distribution and in the half‐life of elimination (t½β). A limited maternal‐fetal transfer of ivermectin was evidenced by a low fetal Cmax (1.72 ± 0.6 ng/mL) and AUC (89.1 ± 11.4 ng·h/mL). While the fetal administration of ivermectin resulted in higher values of clearance (554.1 ± 177.9 mL/kg) and lower values of t½β (8.0 ± 1.4 h) and mean residence time (8.0 ± 2.9 h) indicating that fetal‐placental unit is highly efficient in eliminating the drug as well as limiting the transfer of ivermectin from the maternal to fetal compartment.  相似文献   

14.
The objective of this study was to evaluate neutrophil oxidative metabolism and haemogram in sheep experimentally infected with Haemonchus contortus and supplemented with selenium and vitamin E. Twenty male Corriedale sheep were utilised and distributed into four experimental groups each with five animals infected with larvae: G1‐ supplemented with sodium selenite, 0.2 mg/kg body weight (bw) given intramuscularly (IM); G2‐ supplemented with sodium selenite and vitamin E, 0.2 mg/kg bw and 2000 IU per animal, respectively, both IM; G3‐ supplemented with vitamin E, 2000 IU per animal IM; G4‐ not supplemented. A haemogram and the number of parasite eggs were determined in samples of blood and faeces, respectively, on days zero (T0), 20 (T1), 40 (T2) and 60 (T3) and nitroblue tetrazolium (NBT) assays were performed on heparinized blood samples taken on days zero, 30 and 60. A lower total leucocyte count was detected in G1 in relation to G4 at T4. Lymphocytes were reduced in G1 in relation to G3 and G4 at T3. In both non‐stimulated (NBT‐NS) and stimulated (NBT‐S) dye reduction assays, there was reduced activity at 60 days, in relation to other times in the groups treated with selenium (G1 and G2). On the basis of results obtained, we conclude that supplementation with selenium provides better antioxidant protection to neutrophils.  相似文献   

15.
The objective of this study was to investigate the effects of L‐cysteine‐coated iron oxide nanoparticles on reproductive performance in breeder quails. The five treatment diets consisted of (i) negative control diet not supplemented with iron, (ii) positive control diet supplemented with 60 mg/kg of Fe3O4 and (iii) experimental diets supplemented with 0.6, 6 and 60 mg/kg of L‐cysteine‐coated iron oxide nanoparticles. A total of 100 seven‐day‐old quail chicks were weighed and randomly placed to five groups of five replicate cages. Four quails (one male and three females) were raised in each cage (50 × 15 × 17 cm). Egg production, feed consumption and egg weight were recorded daily and calculated on a hen per day basis. Egg components, fertility, hatchability and day‐old chicks hatched from their eggs were measured at the end of the experiment. The percentage of egg production and egg mass of the 6 mg/kg Fe3O4‐Cys NPs group were significantly higher than those of the control groups. Throughout the experimental period, the highest weekly egg weight was recorded for the 60 mg/kg Fe3O4‐Cys NPs group. Fertility was improved by diet supplemented with iron, both FeSO4 and Fe3O4‐Cys NPs. The breeder fed Fe3O4‐Cys NPs had the highest day‐old chicks weight. The results of this study showed that Fe3O4 nanoparticles that were coated by L‐cysteine could improve availability and utilization of iron in diet. Finally, it was proposed that Fe3O4‐Cys NPs could be used as feed additives in quails.  相似文献   

16.
Induction of superovulation using human menopausal gonadotriphin (hMG) in Japanese Black cattle can result in the recovery of a higher percentage of high quality embryos compared with that using porcine follicle stimulating hormone (FSH). In order to clarify the endocrinological mechanism involved in this discrepancy, 30 superovulation sessions of 17 Japanese Black cattle were studied. Fifteen cattle were super‐stimulated with hMG (total 600 IU), and the remaining 15 cattle were given FSH (total 20 mg). The plasma profiles of LH, estradiol‐17β (E2) and progesterone (P4) were correlated, and the embryo quality was investigated. The total number of ova recovered and the number of transferable embryos tended to be larger in the hMG‐treated group than in the FSH‐treated group. The percentage of excellent embryos tended to be higher in the hMG‐treated group than in the FSH‐treated group (54.3 and 28.7%, respectively, p < 0.10). The E2 level increased during the first 3 days after the initial administration of either hMG or FSH and was higher in the hMG‐treated group than in the FSH‐treated group (p < 0.05). During this period, the E2 level could be categorized into one of the following three types according to whether it increased or decreased and according to the degree of increase or decrease: (1) increase by a factor of 1.2 or more (quick increase type) (2) slight increase by a factor less than 1.2 (slow increase type), and (3) no increase (unstable increase type). In the group treated with hMG, 66.7% of the animals (10 of 15 cattle) showed a quick increase in the E2 level. However, in the FSH‐treated group, 40% (six of 15) of the animals showed a slow increase in the E2 level. The plasma LH level increased dramatically 8 h prior to the peak level in both the hMG‐ and FSH‐treated groups, and then it returned to the basal level 12 h later. After the administration of prostaglandin (PG)F2α, the LH peak level was attained within 44 h in 80% of the animals in the hMG‐treated group, whereas in the FSH‐treated group, the LH peak level tended to be reached later. The P4 level did not increase during the period of hMG or FSH treatment and decreased drastically following administration of PGF2α. After the onset of oestrus, the P4 level was higher in the hMG group than in the FSH group, and 5 to 7 days after oestrus, the level remained higher in the hMG group than in the FSH group (p < 0.05). After the first 3 days of hMG administration, the E2/P4 ratio was higher than that after FSH administration. Furthermore, on the day following PGF2α administration, the ratio was significantly higher in the hMG group than in the FSH group (p < 0.05). These results indicate that superovulation in cattle given hMG results in a significant increase in plasma E2 during the first 3 days and that the increase in the plasma P4 level is larger a few days after oestrus and thereafter compared with FSH‐induced superovulation. Therefore, such plasma level profiles may be related to the increased recovery rate of high quality embryos.  相似文献   

17.
A total of 60 animals (38 cows, 22 heifers) were selected and were divided into three groups of 20 animals each (containing both anoestrus and repeat breeder) in which treatment was performed for 60 days. Group I: control (farmer practice), T1 group: group I?+?hormone (double synch), and T2 group: group I?+?hormone (Estra double synch). The growth performances were measured in terms of body weight and average daily gain (ADG). Blood collection was done at the start and end of the experiment for assessment of blood biochemical, hematological, and reproductive status of the animals. Results revealed significant improvement in growth and reproductive performances in treatment group as compared to control group. Higher percentage of conception was achieved in group III (60%) followed by group II (55%). The least percentage was in group I (15%), i.e., in control group. So it was found that the effect of treating the reproductive-disordered animals with Estra double synch gave comparatively better result than double synch hormonal application.  相似文献   

18.
The crude testicular cells (CTCs) contain many cell types, such as Sertoli cells, leydig cells, spermatogonial stem cells (SSCs), spermatocytes, and other somatic testicular cells, that secrete various growth factors needed in spermatogenesis. The objective of this study was to characterize development of 5‐day‐old mice testicular cells cultured. Crude testicular cells prepared from the testes of 5‐day‐old male mice were cultured in Dulbecco's Modified Eagle Medium and incubated at 37°C in a 5% CO2 atmosphere for 6 days. The results demonstrated that the testicular cells developed rapidly with a population doubling time (PDT) of 0.63 days and more than 90% of cells were viable after being cultured for 3 days. The number of Sertoli‐like cells increased significantly over days 1, 3, and 6 to 22.1%, 34.6%, and 50.1%, respectively. A significant increase was also observed in fibroblast‐like cells (15.5% on day 1 to 28.8% on day 3 and to 26.6% on day 6). In contrast, the number of spermatogonia‐like cells decreased significantly (54.3%, 30.4%, and 18.7%, on days 1, 3, and 6, respectively). These data indicated that the developmental pattern of the testicular cell in this study might be affected by the niche provided by the cultured testicular cells.  相似文献   

19.
Background: Vinblastine (VBL) is commonly used in dogs at a dosage of 2.0 mg/m2. The minimal toxicity observed at this dosage indicates that higher dosages might be well tolerated. Hypothesis: The maximum tolerated dosage (MTD) for a single VBL treatment is higher than the previously published dosage of 2.0 mg/m2. Animals: Twenty‐three dogs with lymphoma or cutaneous mast cell tumors. Methods: Dogs received 1 single‐agent VBL treatment IV. The starting dosage was 3.0 mg/m2, and dosages were increased in increments of 0.5 mg/m2 in cohorts of 3 dogs. Hematologic toxicity was assessed with weekly CBCs. Gastrointestinal toxicity was assessed from medical histories from owners. Once the MTD was determined, additional dogs were treated with VBL at that dosage. Dogs whose cancers responded to VBL continued to receive treatments q2–3 weeks. Results: VBL dosages ranged from 3.0 to 4.0 mg/m2. Neutropenia was the dose‐limiting toxicity, with the nadir identified 7 days after treatment and resolving by 14 days after treatment. The MTD was 3.5 mg/m2. Sixteen dogs were treated at this dosage, and 3 experienced severe toxicity characterized by asymptomatic grade 4 neutropenia, febrile grade 4 neutropenia, and death. Gastrointestinal toxicity was mild and self‐limiting. Preliminary evidence of antitumor activity was identified in 2 of 12 dogs with lymphoma treated at the MTD. Conclusions and Clinical Importance: In dogs, single‐agent VBL is well tolerated at a dosage of 3.5 mg/m2 IV. At this dosage, the minimum safe treatment interval is q2 weeks, and adjunct treatment with prophylactic antibiotics should be considered.  相似文献   

20.
The objective of this study was to evaluate acute endocrine effects as well as histological changes in testicular parenchyma induced by the contraceptive compound RTI‐4587‐073(l). Six miniature stallions were used in this experiment. The treatment group (n = 3) received one oral dose of 12.5 mg/kg of RTI‐4587‐073(l), and the control group (n = 3) received placebo only. The stallions' baseline parameters (semen, testicular dimensions, endocrine values) were collected and recorded for 5 weeks before treatment and for 6 weeks after treatment. Multiple blood samples were collected for endocrine analysis. Testicular biopsies were obtained before treatment, 1 day after treatment and every other week after treatment. Ultrasound exams were performed to monitor the dimensions of the stallions' testes. All stallions were castrated 6 weeks after treatment. Sperm numbers, motility and percentage of morphologically normal sperm decreased (p < 0.05), while the number of immature germ cells increased in ejaculates from treated animals (p < 0.05). Serum concentrations of inhibin and follicle‐stimulating hormone did not change. Testosterone concentrations initially transiently decreased (p < 0.05) after administration of RTI‐4587‐073(l), and increased several days later (p < 0.05). Testicular content of testosterone and estradiol 17‐β was lower in treated stallions than in control stallions on Day 1 after treatment (p < 0.05). Severe disorganization of the seminiferous tubules, significant loss of immature germ cells and complete depletion of elongated spermatids were observed in testicular biopsies obtained from treated stallions 1 day, 2 and 4 weeks after treatment. These changes were still present in the testicular samples taken from treated stallions after castration. The results of this study confirmed that RTI‐4587‐073(l) has antispermatogenic effects in stallions. Furthermore, we concluded that this compound causes acute sloughing of immature germ cells from the seminiferous tubules. RTI‐4587‐073(l) has significant but transient effects on Leydig cell function in stallions.  相似文献   

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