Induction of double ovulation in mares using deslorelin acetate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aspiration of equine oocytes from immature follicles after treatment with equine pituitary extract (EPE) alone or in combination with hCG

This study examined the effect of treating mares with equine pituitary extract (EPE) alone or in combination with hCG on the recovery rate of immature follicles by transvaginal follicular aspiration (ovum pick-up; OPU). Ten normally cycling crossbred mares aged 3-15 years and weighing 350-400 kg were subjected to each of three treatments in a random sequence with each exposure to a new treatment separated by a rest cycle during which a spontaneous ovulation occurred. The treatments were (1) superovulated with 25 mg EPE and treated with 2500 IU hCG, (2) superovulation with 25 mg EPE, and (3) control (no exogenous treatment). Treatments 7 days after spontaneous ovulation; and all the follicles > 10 mm were aspirated 24 h after the largest follicle achieved a diameter of 27-30 mm for control group, and most follicles reached 22-27 mm for the EPE alone treatment. To the group EPE+hCG, when the follicles reached 22-27 mm, hCG was administered, 24 h before OPU. Superovulation increased the number of follicles available for aspiration. The total number of follicles available for aspiration was 61 in the EPE/hCG group. 63 in the EPE group and 42 in the control. The proportion of follicles aspirated varied from 63.5% to 73.8%. Oocyte recovery rate ranged from 15.0% to 16.7% and the proportion of mares that yielded at least one oocyte was 70% (7/10) in the EPE/hCG, 60% (6/10) in the EPE alone and 50% (5/10) in control group. The EPE/hCG treatment had a higher proportion of follicles with expanded granulose cells (64.4%) than the control (3.3%: p < 0.05) and the EPE treatment (25.0%). The intervals from spontaneous ovulation to aspiration were similar for all treatments (11-12 days). However, superovulatory treatment significantly increased the aspiration to ovulation interval from 15 +/- 4 days for control to 27 +/- 15 days for EPE (p < 0.05) and to 23 +/- 13 days for EPE/hCG treatment with commensurate increases in the time between spontaneous ovulations. (c) 2008 Elsevier B.V. All rights reserved.

Use of a Low Dose of Equine Purified FSH to Induce Multiple Ovulations in Mares

The effects of a low dose of equine purified FSH (eFSH) on incidence of multiple ovulations and embryo recovery rate in mares were studied. During the physiological breeding season in Brazil (19 degrees 45'45'S), 14 Mangalarga Marchador donor mares were used in a crossover study and another 25 mares of the same breed, between 3 years and 12 years of age were used as recipients for the embryo transfers. Donors were monitored during two consecutive oestrus cycles, an untreated control cycle followed by a treated cycle, when eFSH was administered. In both cycles, after an embryo collection attempt on day 8 post-ovulation all mares received 7.5 mg dinoprost and had their two largest follicles tracked daily by ultrasonography until the period of ovulation. Mares were inseminated every 48 h with extended fresh semen from a single stallion after the identification of a 35-mm follicle until the period of ovulation. Ovulations were induced by intravenous administration of 2.500 IU of human chorionic gonadotropin, upon detection of a 35- to 40-mm follicle. In the treated cycle, 5 mg eFSH was given intramuscularly once a day, from day 8 post previous ovulation until at least one follicle reached 35 mm in diameter. Embryo flushes were performed on day 8 of dioestrus (day 0 = ovulation). Treatment with eFSH resulted in higher (p < 0.05) ovulation rate and incidence of multiple ovulations compared to the control (1.6 vs 1.0 and 50% vs 0%, respectively - one mare had triple ovulation). However, embryo recovery rates in the control and treated cycles were similar (0.8 and 1.0, respectively; p > 0.05). Pregnancy rates in the recipient mares following embryo transfer were similar for the control and eFSH cycles (11/11 and 10/14, respectively). Additional studies are necessary in order to develop a low-dose protocol for the use of eFSH that brings a more consistent contribution to the efficiency of commercial equine embryo transfer programs.

Embryo Transfer Efficiency of Quarter Horse Athletic Mares

This study was designed to compare embryo recovery rates and pregnancy rates of athletic and breeding Quarter Horse mares in a tropical warm climate. Thirty-nine barrel racing mares in training and 135 breeding mares as control donors were included. During the training period, the ambient temperature ranged from 31 degrees C to 36 degrees C and the average humidity from 70% to 90%. After the detection of a 35-mm follicle by ultrasound, ovulation was induced with 1 mg of deslorelin acetate (i.m), and insemination was performed 24 hours later with cooled and fresh semen from different fertile stallions. Embryos were collected on day 8 postovulation. The body temperature (rectal) was evaluated from eight athletic donor mares randomly selected from the same studied group. A total of 138 and 657 embryo collections were carried out on training and breeding mares, respectively, with a total of 105 (76%) and 466 (71%) embryos collected (P > .05). Similarly, no differences (P > .05) were observed for the pregnancy rates on day 15 (82/105, 78% vs. 370/466,79%), and day 40 (73/105, 69% vs. 328/466,70%) between the training and breeding donor mares. Just after training, the body temperature increased to an average of 39.4 degrees C and the respiratory rate from 14.5 to 35.3 breaths per minute. The results of the present study showed that embryo production from appropriately trained donor mares in good condition were similar to non-athletic broodmares. (C) 2011 Published by Elsevier B.V.

Ultra-sonografia do fígado, aparelho renal e reprodutivo da jibóia (Boa constrictor)

Atualmente os animais silvestres têm despertado o interesse particular na criação domestica. Na medicina de animais selvagens, os exames ultra-sonográficos podem ser considerados como ferramenta para diagnosticar e prevenir doenças. Deste modo, realizou-se um estudo em 20 jibóias (Boa constrictor), a fim de caracterizar a morfologia e aparência ultra-sonográfica das estruturas presentes da cavidade celomática desses animais. Ultra-sonograficamente, o fígado apresentou-se variando de hipoecóica a levemente hiperecogênica, com margens ecogênicas e ecotextura homogênea em toda sua extensão. Os rins mostraram formato elipsóide, com cápsula fina, regular e hiperecóica. Os folículos ovarianos apresentaram formato ovóide, margens finas, regulares e discretamente hiperecóicas. As estruturas do sistema reprodutor do macho não foram evidenciadas com precisão, devido a sua ecogenicidade similar em relação às estruturas adjacentes e pela presença do corpo gorduroso localizado nessa região. A ultra-sonografia da cavidade celomática em jibóias demonstrou ser uma técnica rápida e de fácil acesso, permitindo identificar a morfologia, sintopia e aparência ultra-sonográfica de estruturas como o fígado, rins e de folículos vitelogênicos nas fêmeas.

Follicular Development in Ewes During Natural and Prostaglandins Induced Estrous Cycle

The follicular development was evaluated in ovine females during natural and prostaglandin-F(2 alpha) (PG) induced estrous cycle. Ewes were randomly divided in two treatments (n=7/treatment): T1 with natural cycle and T2 synchronized with two injections of PG. From one day before PG injection until next ovulation, daily transrectal ultrasonography was done. All follicles >= 2 mm were assessed. During the interovulatory intervals, follicular growth and regression occurred in a wave like pattern (2-3 waves). The maximum diameter of the largest follicle of the first wave was greater in T1 (5.83 +/- 0.31 mm) compared with T2 (5.0 +/- 0.1 mm; P<0.01), but there was no significant difference among the emergency day of largest follicle, during the growth phase of the follicular waves. The duration of the plateau phase in wave 2 differed between the two treatments (P<0.05) showing 0.83 +/- 0.31 and 1.83 +/- 0.17 d, for natural and synchronized treatment, respectively. Growth rate did not differ between treatments. Presence of new luteal tissue was detected on day 3 after ovulation. In conclusion, the follicular development was similar in female ovine during natural and PG induced estrous cycle.

Reuse of norgestomet implants in an eCG-based superovulation protocol administered to Nelore (Bos taurus indicus) cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of two estradiol esters (benzoate and cypionate) on the induction of synchronized ovulations in Bos indicus cows submitted to a timed artificial insemination protocol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relationship Between the Prevalence of the Dentigerous Cyst and the Odontogenic Keratocyst Tumor and the Current Etiologic Hypothesis

Cysts are considered as nonneoplastic benign lesions that, when present for a long period of time, can cause some discomfort, especially related to the treatment form. Among the types of cysts of the maxilla, the dentigerous cyst (DC) presents substances between the dental follicle and the crown of the tooth with high potential for resorption, and the odontogenic keratocyst tumor (OKT) characterizes for its noticed rapid growth pattern and the possibility to develop carcinomas in the lesion wall. The DC is the most common type among the developing odontogenic cystic lesions, while the OKT represents 10% of these lesions. The prevalence of the OKT found in the current study was superior to the DC, opposing data of the evaluated literature, as well as the predominance in relation to the age group. Dentigerous cyst cases were found mostly in younger individuals, whereas the OKT was observed mainly in individuals between the third and fourth decades of life. This fact reflects the fragility of these features while establishing the presumptive diagnosis and insinuates the strong relation with a probable genetic predisposition. In relation to sex and race, the findings in this article were similar to those found in the literature, highlighting the possibility of a hormonal involvement. However, the anatomopathologic examination remains essential to define the main diagnosis of the lesions observed by means of imaging examinations, providing for safer diagnoses to plan the treatment.

Estrous behavior and the estrus-to-ovulation interval in Nelore cattle (Bos indicus) with natural estrus or estrus induced with prostaglandin F2 alpha or norgestomet and estradiol valerate

Estrous behavior and the estrus-to-ovulation interval are essential for estimating the best time to artificially inseminate cattle. Because these parameters are not well characterized in the Nelore breed (Bos indicus), the main purpose of the this study was to determine the estrus-to-ovulation interval in Nelore heifers and cows with natural estrus or with estrus induced by treatments with PGF2 alpha or norgestomet and estradiol valerate (NEV). The cows and heifers were observed continuously (24 h a day) to determine the onset of estrus and to study estrous behavior in the cows. Ten hours after the start of estrus the ovaries were scanned every 2 h by ultrasonography to monitor the dominant follicle until ovulation. Blood samples were collected periodically to determine progesterone levels by RIA. Administration of PGF2 alpha (2 injections, 11 days apart) did not induce estrus in most Nelore females in spite of the presence of functional CL, indicated by progesterone concentrations above 6.0 ng/ml in 25 of 28 animals. Treatment with NEV induced high sexual receptivity in cows (10/11), but only 66% ovulated. Cows with natural or induced estrus exhibited behavioral estrus of 10.9 +/- 1.4 h, and ovulation occurred 26.6 +/- 0.44 h (n = 26) after the onset of estrus. In most of the cows (53.8%) estrus began at night (between 1801 and 600 h), and 34.6% it started and finished during the night. It is concluded that in Nelore females ovulation occurs approximately 26 h after the onset of estrus. Additionally, estrous behavior is shorter than in European breeds, and there is a high incidence of estrus at night, which makes it difficult to detect and, consequently, impairs Al in Nelore cattle. The observation that a high percentage of Nelore females with an active CL did not respond to usual dosages of PGF2 alpha warrants further investigation. (C) 1998 by Elsevier B.V.

Influence of Superovulatory Protocols on In Vitro Production of Nellore (Bos indicus) Embryos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Expression of fibroblast growth factor-8 and its cognate receptors, fibroblast growth factor receptor (FGFR)-3c and-4, in fetal bovine preantral follicles

Paracrine cell signaling is thought to be important for ovarian follicle development, and a role for some members of the fibroblast growth factor (FGF) family have been suggested. In the present study, we tested the hypothesis that FGF-8 and its cognate receptors (FGFR-3c and FGFR-4) are expressed in bovine preantral follicles. Reverse transcription-polymerase chain reaction was used to amplify bovine FGF-8, FGFR-3c, and FGFR-4 from preantral follicle samples and a variety of fetal and adult tissues. All three genes were widely expressed in fetal tissues, with a restricted expression pattern in adult tissues. FGF-8 and FGFR-3c were expressed in secondary follicles in 70% of fetuses examined, whereas FGFR-4 expression was significantly less frequent (20%). FGFR-3c expression frequency was significantly lower in primordial compared to secondary follicles, and FGF-8 expression showed a similar trend. FGFR-4 was only observed when all follicle classes of an individual were expressing both FGF-8 and FGFR-3c. We conclude that FGF-8 and its receptors are expressed in preantral follicles in a developmentally regulated manner. (C) 2005 Wiley-Liss, Inc.

Synchronization of ovulation in beef cows (Bos indicus) using GnRH, PGF2 alpha and estradiol benzoate

The objective of this study was to evaluate protocols for synchronizing ovulation in beef cattle. In Experiment 1, Nelore cows (Bos indicus) at random stages of the estrous cycle were assigned to 1 of the following treatments: Group GP controls (nonlactating, n=7) received GnRH agonist (Day 0) and PGF2 alpha (Day 7); while Groups GPG (nonlactating, n=8) and GPG-L (lactating, n=9) cows were given GnRH (Day 0), PGF2a (Day 7) and GnRH again (Day 8, 30 h after PGF2 alpha). A new follicular wave was observed 1.79+/-0.34 d after GnRH in 19/24 cows. After PGF2a, ovulation occurred in 19/24 cows (6/7 GP, 6/8 GPG, 7/9 GPG-L). Most cows (83.3%) exhibited a dominant follicle just before PGF2a, and 17/19 ovulatory follicles were from a new follicular wave. There was a more precise synchrony of ovulation (within 12 h) in cows that received a second dose of GnRH (GPG and GPG-L) than controls (GP, ovulation within 48 h; P<0.01). In Experiment 2, lactating Nelore cows with a visible corpus luteum (CL) by ultrasonography were allocated to 2 treatments: Group GPE (n=10) received GnRH agonist (Day 0), PGF2a (Day 7) and estradiol benzoate (EB; Day 8, 24 h after PGF2 alpha); while Group EPE (n=11), received EB (Day 0), PGF2a (Day 9) and EB (Day 10, 24 h after PGF2a). Emergence of a new follicular wave was observed 1.6+/-0.31 d after GnRH (Group GPE). After EB injection (Day 8) ovulation was observed at 45.38+/-2.03 h in 7/10 cows within 12 h. In Group EPE the emergence of a new follicular wave was observed later (4.36+/-0.31 d) than in Group GEP (1.6+/-0.31 d; P<0.001). After the second EB injection (Day 10) ovulation was observed at 44.16+/-2.21 h within 12 (7/11 cows) or 18 h (8/11 cows). All 3 treatments were effective in synchronizing ovulation in beef cows. However, GPE and, particularly EPE treatments offer a promising alternative to the GPG protocol in timed artificial insemination of beef cattle, due to the low cost of EB compared with GnRH agonists. (C) 2000 by Elsevier B.V.

Synchronization of ovulation in crossbred dairy heifers using gonadotrophin-releasing hormone agonist, prostaglandin F2a and human chorionic gonadotrophin or estradiol benzoate

Girolando (Gir x Holstein) is a very common dairy breed in Brazil because it combines the rusticity of Gir (Bos indicus) with the high milk yield of Holstein (Bos taurus). The ovarian follicular dynamics and hormonal treatments for synchronization of ovulation and timed artificial insemination were studied in Girolando heifers. The injection of a gonadotrophin-releasing hormone (GnRH) agonist was followed 6 or 7 days (d) later by prostaglandin F2a (PGF2a). Twenty-four hours after PGF2a injection either human chorionic gonadotropin (hCG, GPh-d6 and GPh-d7 groups) or estradiol benzoate (EB, GPE-d6 and GPE-d7 groups) was administered to synchronize ovulation and consequently allow timed artificial insemination (AI) 24 and 30 h after hCG and EB injection, respectively. Follicular dynamics in Girolando heifers was characterized by the predominance of three follicular waves (71.4%) with sizes of dominant follicles (10-13 mm) and corpus luteum (approximately 20 mm) similar to those for Bos indicus cattle. In the GnRH-PGF-hCG protocol, hCG administration induced earlier ovulation (67.4 h, P<0.01) compared to the control group (GnRH-PGF) and a better synchronization of ovulation, since most of it occurred within a period of 12 to 17 h. Pregnancy rate after timed AI was 42.8 (3/7, GPh-d6) to 50% (7/14, GPh-d7). In contrast, estradiol benzoate (GnRH-PGF-EB protocol) synchronized ovulation of only 5 of 11 heifers from the GPE-d7 group and of none (0/7) from the GPE-d6 group, which led to low pregnancy rates after timed AI (27.3 and 0%, respectively). However, since a small number of Girolando heifers was used to determine pregnancy rates in the present study, pregnancy rates should be confirmed with a larger number of animals.

Acceleration of Sperm Transit Time and Reduction of Sperm Reserves in the Epididymis of Rats Exposed to Sibutramine

Sibutramine is a drug globally used for the treatment of obesity. The aim of this study was to investigate male reproductive disorders caused by sibutramine in adult rats. Wistar rats were treated for 28 consecutive days (gavage) with 10 mg/kg of sibutramine. Control animals received only vehicle (dimethylsulfoxide and saline). The rats were sacrificed for evaluation of body and reproductive organ weights, sperm parameters, hormone levels (luteinizing hormone, follicle-stimulating hormone, and testosterone), testicular and epididymal histopathology, sexual behavior, fertility and in vitro contractility of the epididymal duct. Sibutramine decreased (P < .05) weights of the epididymis and ventral prostate, but not of other reproductive organs. The sperm number and transit time in the epididymal cauda were decreased (P < .001), but the daily sperm production was not altered. Moreover, morphology and sperm motility, histopathology of the testes and epididymis, sexual behavior, fertility, and serum hormone levels were not altered by the treatment. Sibutramine increased the potency of norepinephrine and, per se, increased the mechanical activity of the epididymal duct in vitro. Thus, although sibutramine in these experimental conditions did not interfere with the reproductive process of rats, it provoked acceleration of the sperm transit time and a decrease in the sperm reserves in the epididymal cauda. This alteration is probably related to the sympathomimetic effect of this drug, as shown by the in vitro assays. In humans, use of this drug might present a threat for male fertility because sperm reserves in men are naturally lower than those in rats.