Indução do estro em cutias (Dasyprocta leporina) utilizando-se protocolos à base de prostaglandina isolada ou em associação com análogo de GnRH / Estrus induction in agoutis (Dasyprocta leporina) using protocols based on prostaglandin isolated or in association to GnRH analogue

Comparou-se a eficiência de protocolos para indução de estro em cutias. Em cinco fêmeas, foram administradas duas doses de cloprostenol (5µg) com intervalo de nove dias, via intraperitoneal; em outras cinco, administraram-se 30µg de análogo do hormônio liberador de gonadotrofinas (GnRH), via intravulvar, seguidos de 5µg de cloprostenol, via intraperitoneal, após sete dias e, após mais dois dias, nova dose do análogo de GnRH. A cada três dias, a ciclicidade reprodutiva dos animais foi monitorada, por meio de coleta de sangue, para dosagem hormonal, ultrassonografia ovariana e citologia vaginal. Duas das fêmeas que receberam apenas prostaglandina, as quais estavam em fase luteal no início do tratamento, manifestaram o estro aos três e seis dias após a segunda administração da droga. Já nas fêmeas que receberam a prostaglandina associada ao análogo do GnRH, duas que originalmente estavam em fase luteal apresentaram estro aos quatro dias após o tratamento, e uma outra apenas após 10 dias. Não foram evidenciadas diferenças estatísticas quanto à eficiência dos tratamentos (P>0,05). Conclui-se que, de acordo com os protocolos utilizados, o uso da prostaglandina isolada ou em associação com análogo do GnRH para a indução do estro em cutias D. leporina apresenta eficiência limitada às fêmeas que estejam em fase luteal por ocasião do início do tratamento.(AU)

We compared the efficiency of protocols for estrus induction in agoutis. Five females received double intraperitoneal administration of cloprostenol (5µg) on a 2-days interval; other five females were treated with intravulvar administration of 30µg gonadotrophin release hormone analogue (GnRH associated to intraperitoneal administration of 5µg cloprostenol after seven days and a new administration of GnRH analogue after two days. Every 3 days, the agoutis' reproductive cycle was monitored by blood collection for hormonal analysis, ovarian ultrasound and vaginal cytology. Two females, originally in luteal phase, that received isolated prostaglandin presented estrous signs at 3 and 6 days after the second drug administration. From the females that received the association, two that were originally in luteal phase presented estrus at 4 days after treatment, and one other presented estrus only after 10 days. There was no significant statistical difference regarding the efficiency of treatments for estrus induction (P>0.05). We conclude that, according to the protocols tested in the study, the use of isolated prostaglandin or its association to GnRH analogue for estrus induction in D. leporine shows an efficiency limited to the females that were in luteal phase in the beginning of the treatment.(AU)

Experimental Tityus serrulatus scorpion envenomation: age- and sex-related differences in symptoms and mortality in mice

Among the various methods for evaluating animal venom toxicity, the calculation of the median lethal dose (LD50) is the most widely used. Although different protocols can be used to calculate the LD50, the source of the venom and the method of extraction, as well as the strain, age, and sex of the animal model employed, should be taken into consideration. The objective of the present study was to evaluate the influence of sex and age on the toxicity of Tityus serrulatus scorpion venom in Swiss mice. Although the symptoms of envenomation were similar in male and female animals, female mice proved to be more resistant to the venom. In females, age had no impact on the susceptibility to scorpion envenomation. Male mice were more sensitive to T. serrulatus venom. Moreover, in males, age was an important parameter since sensitivity to the venom increased with age.