Pharmacological approaches to induce follicular growth and ovulation for fixed-time artificial insemination treatment regimens in ewes.

In Experiment I, during the non-breeding season, after intravaginal devices containing progesterone (P4) were withdrawn (n = 28), estrous rates were greater with treatment with 400 IU eCG (P < 0.05) than with FSH (10 and 15 mg) and no treatment. During the breeding season (n = 147), estrous and pregnancy rates after fixed-time artificial inseminations (FTAI) were similar among groups: 300 IU eCG; 10 mg FSH; and control (P > 0.05). In Experiment II (non-breeding season), ewes of one group were treated with 300 IU eCG (n = 8) and of two groups were treated with 10 mg FSH. In one FSH group, 250 µg estradiol benzoate (EB) were administered after 24 h (n = 9); in the other, 4 µg GnRH were administered after 36 h (n = 10). Serum P4 concentrations were greater in eCG-treated ewes (P < 0.05). Estrous rates were similar for the eCG- and FSH plus EB-treated ewes (P > 0.05). In Experiment III (breeding season), the treatments were: 300 IU eCG; 250 µg estradiol cypionate; 250 µg EB; or control (n = 22). Follicular growth was greater for eCG-treated ewes within 0-24 h and for control ewes within 48-72 h (P = 0.001). Although estrous and ovulation rates did not differ (P > 0.05), all eCG-treated ewes had ovulations. During the non-breeding season, FSH treatment promoted follicular growth but did not induce ovulations. For FTAI regimens, eCG was more effective than FSH plus GnRH and estradiol esters in inducing estrus and ovulation.

Antioxidant Effect of Xanthan Gum on Ram Sperm after Freezing and Thawing.

BACKGROUND: Xanthan gum is used as thickener in media to preserve food products, having cryoprotectant and antioxidant properties that may be relevant for sperm cryopreservation. OBJECTIVE: To evaluate the effects of adding xanthan gum to freezing extenders on post-thawing quality and oxidant activity of ram sperm. METHODS: Ejaculates from seven rams extended TRIS-egg yolk-glycerol were split in three treatments including xanthan gum (0.15%; 0.20%; and 0.25%) and a control with no xanthan gum. RESULTS: After thawing, motility and production of reactive oxygen species (ROS) with 0.20% and 0.25% xanthan gum were lower than for the control (P < 0.05), but mitochondrial functionality and integrity of membrane, acrosome and DNA did not differ (P > 0.05). Xanthan gum at 0.20% and 0.25% may be an efficient antioxidant for frozen-thawed ram sperm, due to the reduction in ROS production.

Effect of ß-mercaptoetanol and cysteine on post-thawing quality and oxidative activity of ram sperm and on the viability of vitrified sheep embryos / Efeito do ß-mercaptoetanol e da cisteína sobre a qualidade e a atividade oxidativa do sêmen ovino após o descongelamento e sobre a viabilidade de embriões ovinos vitrificados

The effects of ß-mercaptoethanol (BME) and cysteine on the viability and oxidative activity of ram sperm after thawing and on development in vitro and viability of vitrified sheep embryos were evaluated. Ejaculates from four rams were pooled and extended, composing six treatments: no antioxidants; 2mM BME; 5mM BME; 2mM BME and 5mM cysteine; 5mM BME and 5mM cysteine; and 5mM cysteine. Sperm motility, membrane and acrosome integrity, mitochondrial functionality, production of reactive oxygen species and total antioxidant capacity were similar across treatments (P>0.05). A medium with no antioxidant presented cleavage and blastocyst development rates (60.3% and 33.6%, respectively) similar (P>0.05) to those of a medium with 50µM BME and 600µM cysteine (64.3% and 36.6%, respectively). Post-thawing viability of vitrified embryos was similar between media (P>0.05). Cysteine and BME had no influence on the post-thawing viability and oxidative activity of ram sperm and on the viability of vitrified sheep embryos.(AU)

Foram avaliados os efeitos do ß-mercaptoetanol (BME) e da cisteína sobre a viabilidade e a atividade oxidativa após o descongelamento do sêmen ovino e sobre o desenvolvimento in vitro e a viabilidade de embriões ovinos vitrificados. Ejaculados de quatro carneiros foram agrupados e diluídos, compondo seis tratamentos: sem antioxidantes; com BME 2mM; com BME 5mM; com BME 2mM e cisteína 5mM; com BME 5mM e cisteína 5mM; e com cisteína 5mM. Motilidade, integridade da membrana e do acrossoma, função mitocondrial, produção de espécies reativas de oxigênio e capacidade antioxidante total foram semelhantes entre os tratamentos (P>0,05). Em um meio sem antioxidantes, as taxas de clivagem e de desenvolvimento embrionário até blastocisto (60,3%, e 33,6%, respectivamente) foram semelhantes (P>0,05) às obtidas em um meio com BME 50µM e cisteína 600µM (64,3% e 36,6%, respectivamente). A viabilidade pós-descongelamento dos embriões vitrificados não diferiu entre os meios (P>0,05). O BME e a cisteína não influenciaram a viabilidade e a atividade oxidativa do sêmen ovino após o descongelamento e a viabilidade de embriões ovinos vitrificados.(AU)

Presence of leptin and its receptor in the hypothalamus, uterus and ovaries of Swine females culled with distinct ovarian statuses and parities.

Leptin acts on energy metabolism, affecting reproductive functions through activation of its receptors in the brain and in reproductive organs. This study compared the presence of leptin and its receptor (ObR-b) in hypothalamus neurons, endometrial glands and oocytes of culled swine females across ovarian statuses and parities. Immunohistochemistry was done in samples of uterus, ovaries and hypothalamus from 28 culled females, using polyclonal antibodies antileptin and ObR-b. Immunolabelling was compared for sows categorized by parity at culling (0, 1, 2-4 and <4) and ovarian status (luteal and follicular phases of the oestrous cycle and with cysts). Immunolabelling for leptin and ObR-b in neurons and oocytes was weaker in females with cysts (p < 0.05) than in those at the follicular phase. In endometrial glands, leptin immunolabelling was less intense in females with cysts (p < 0.05), but immunolabelling for ObR-b was similar across ovarian statuses (p > 0.05). In sows culled with 2-4 parities, leptin immunolabelling in neurons and endometrial glands was more intense than in nulliparous females (p < 0.05). In comparison with sows culled at greater parities, ObR-b immunolabelling for nulliparous females was less intense in endometrial glands and in oocytes (p < 0.05), but more intense in neurons (p < 0.05). Thus, in swine, the presence of leptin and ObR-b varies across parities and is more intense in the uterus, ovaries and hypothalamus of females that were cycling before culling than in those having cystic ovaries.