Synchronization of estrus in paca (Cuniculus paca L. ): possible impacts on reproductive and productive parameters / Sincronização do estro em pacas (Cuniculus paca L. ): possíveis impactos sobre parâmetros reprodutivos e produtivos

Estrus synchronization is a reproductive biotechnology used to improve artificial insemination or pairing through the manipulation of the estrous cycle at a desirable time. Employing this technique in captive pacas (Cuniculus paca L.) is important because it creates expectation of meeting the demand for paca meat and, consequently, reduces poaching. Thus, this research aims to verify the effect of a progestogen implant associated with two doses of eCG on the synchronization and induction of fertile estrus. Twenty-seven adult pacas were used, 18 non-pregnant females and nine males, divided into three groups. G1 and G2 females groups (treatments) received 1.5 mg Norgestomet and were injected intramuscularly, seven days later, with 0.13 mg of prostaglandin. After 24 hours the implants were removed and the animals immediately received 25 IU and 50 IU of ECG intramuscularly, respectively. The mating of the three groups took place on the same days. G3 females' group (control) showed estrus on different days after D0. Females under treatment displayed estrus only after removing the implant (D8). G1, G2, and G3 pregnancy rates were 100%, 66%, and 50%, respectively. Regarding births per parturition, 100% of G1 and G3 produced one offspring, while 50% of G2 produced two. Progestogen in the form of subcutaneous implants was effective in mimicking the luteal phase of the estrous cycle. After removal, implants favored the occurrence of a fertile estrus. As a conclusion, further studies must be conducted in order to establish in-depth possible association between 50 IU of eCG, and the occurrence of twin pregnancies.(AU)

A sincronização é uma biotécnica reprodutiva que melhora a porcentagem de cobertura por meio da manipulação do ciclo estral. Empregar esta biotécnica em pacas de cativeiro (Cuniculus paca L.) é importante, pois cria-se a expectativa de que a demanda pela carne seja atendida e a caça ilegal diminua. O objetivo da pesquisa foi verificar o efeito de implantes de progestágenos associados a duas doses de gonadotrofina coriônica equina (eCG) na sincronização e indução de cios férteis de pacas. Foram utilizadas 18 fêmeas não prenhas e nove machos, divididos em três grupos. Fêmeas do G1 e G2 receberam implantes com 1,5mg de Norgestomet e, sete dias depois, 0,13mg de prostaglandina via intramuscular (IM). No dia 8 (D8), foram retirados os implantes e G1 e G2 receberam 25 UI e 50 UI de eCG, IM, respectivamente; G3 foi o controle. O pareamento nos três grupos aconteceu nos mesmos dias. As fêmeas do G3 apresentaram cio alguns dias após o dia zero (D0). Fêmeas que receberam tratamento apresentaram cio só após a retirada do implante no dia 8 (D8). As taxas de prenhez de G1, G2 e G3 atingiram 100%, 66% e 50%, respectivamente. Em relação a filhotes por parto, 100% do G1 e G3 produziram uma cria, enquanto 50% do G2 produziram duas crias. O progestágeno do implante foi eficaz em mimetizar a fase lútea do ciclo estral. Após a remoção, o tratamento hormonal favoreceu a ocorrência de cio fértil. Outros estudos devem ser realizados a fim de estabelecer uma possível associação entre 50 UI de eCG e a ocorrência de gestações gemelares.(AU)

Effect of modified egg* on developmental defects in neonates of NIDDM induced Wistar rats.

Maternal Zn deficiency has been suggested as the contributing factor for all congenital malformations during pregnancy particularly in diabetes. Maternal Zn-supplementation, therefore, was suggested as one possible nutrition intervention during pregnancy to improve its outcome. But a number of trials with Zn-supplementation are not consistent and discourage the use of excessive Zn-supplementation during pregnancy. Instead a multivitamin/ mineral supplement to them has been suggested to reduce its complication. Accordingly, the poultry egg was modified for trace elements, vitamin-E and omega-3 fatty acids so as to use it as a dietary supplement for diabetics to reduce their complications during the pregnancy. The results showed that NIDDM induced rats fed either on 40 or 80 mg Zn/kg diet delivered less number of pups/litter and their body weight was higher at birth as compared to control group fed 20 mg Zn/kg diet. During the weaning period, some abnormalities characterized by restricted movements of the hind legs, curl toes of limbs, eye opening problems, less hair on the body and more head to body ratio were observed. Whereas number of pups delivered per litter were more with higher body weights without abnormalities in the pups in NIDDM groups fed egg mixed diet. Further Zn, Cu and Mg concentrations were significantly less in the liver, hair and abdominal muscles in pups in NIDDM groups but their concentrations were restored approaching closer to control in pups in groups fed egg mixed diet estimated on 18th day of weaning period. The excretion of these trace elements increased in the urine of dams fed Zn supplemented diet but decreased in the dams fed egg mixed diet on 15th day of their suckling period. The data suggest that if these modified eggs are included in the regular diet during pregnancy, they may protect the neonates in womb against the damaging effect of imbalances of physiologically important nutrients due to diabetes or environmental contamination.

Study of anti-fertility effect of lemon seeds (Citrus limonum) in female albino mice.

Among the citrus species, Citrus-limonum is native of North West region of India. The petroleum ether, alcoholic and aqueous extracts of Citrus-limonum (lemon) seeds were investigated for anti-fertility effect in female albino mice. The extracts were administered orally for 7 days after insemination (i.e. post-ovulatory test). The control group received 4% gum acacia. The animals were examined for implantation sites on 10th day of pregnancy and the number of pups delivered at term for each group was recorded. The alcoholic extract showed significant anti-fertility effect as compared to petroleum ether and aqueous extracts. The alcoholic extract was subjected for fractionation and the fractions were again tested for their anti-fertility effect. The fraction of ethyl-acetate (12-25 fractions) showed most encouraging anti-fertility activity. In second part of the study, the alcoholic extract and its ethyl-acetate fraction (12-25 fractions) were subjected to evaluation of their mechanism of action and it was found that their principal mode of action is as an anti-zygotic agent. Withdrawal of the test drug, resulted in complete restoration of fertility. Thus the ethyl-acetate fraction (12-25 fractions) of alcoholic extract of lemon seeds exerted reversible anti-fertility effect in female mice by virtue of its anti-zygotic action.

Effect of methyl parathion formulation on estrous cycle and reproductive performance in albino rats.

The animals were injected intraperitoneally with graded doses of methyl parathion at 1.5 to 3 mg/kg body weight for 15 days from the day of estrus. Results indicated that the methyl parathion treatment showed irregular estrous cycles, affect the duration of each estrous cycle, proestrus and diestrus were significantly changed in 2.5 and 3 mg treatment groups. But there was no significant change in the number and duration of each estrous cycle, duration of proestrus and diestrus in 1.5 and 2 mg methyl parathion treatment groups. However, there was a significant decrease in the duration of estrus, while there was no significant change in the duration of metestrus in all methyl parathion treatment rats when compared with those of the corresponding parameters of the control. There was no significant effect on number of live pups on day 1 and 5 except in 3 mg methyl parathion treatment group where it was significantly decreased. There was no significant change in reproductive indices like pregnancy, parturition, live birth and viability in all the methyl parathion treatment rats except the viability index in the highest dose.

Prolactin suppression during pre and post-implantation periods on rat uterine glucosamine synthase activity.

Administration of bromocriptine (Bc), an ergot derivative having dopamine receptor agonist activity, to rats on day 1-5 of pregnancy prevented implantation of blastocysts and significantly suppressed uterine glucosamine 6-phosphate synthase activity. There was no effect on implantation or the enzyme activity when Bc was injected on day 7 or later of pregnancy. Injection of prolactin following Bc partially restored the enzyme activity and increased number of implantation sites. These results indicate that suppression of prolactin on day 1 to 5 of pregnancy causes failure of implantation. Bc on day 9 or later had no effect possibly due to the availability of placental LH/hCG to support the luteal cells.

Antifertility effects of leaf extracts of some plants in male rats.

Ethanolic leaf extracts of different local folklore plants (Azadirachta indica, Beaumontia grandiflora, Chordia dichotoma, Casiarea tomentosa, Diospyros embryopteris, Milletia auriculata and Melia azedarach) were investigated for antifertility effects on male rats in oral doses of 100 mg/kg daily for 21 days. Though, none of these extracts interfered with spermatogenesis, anti-implantational and abortifacient effects were observed in females mated by the males fed with leaf extracts of A. indica and C. dichotoma. Leaf extract of B. grandiflora besides having anti-implantational and abortifacient effects, had luteolytic effects. Abolition of libido in 100% males by leaf extracts of D. embryopteris and M. azedarach and in 60% of males by extract of C. tomentosa preclude these plants for antifertility use.

Effects of tolueno exposure during gestation on neurobehavioral development of rats and hamsters

Pregnant rats and hamsters were exposed to toluene vapor (800mg/m3) 6h daily from gestation days 14 to 20, and 6 to 11, respectively. Growth, neuromotor development and performance of the offspring in behavioral tasks were assessed. In rats,toluene increased the number of litters with low birth weight pups. Male rat offspring exposed to toluene displayed shorter latencies than male controls to choose one side of a T maze in a spontaneous alternation test. Hamsters exposed to toluene performed worse in a rotating rod test. These results confirm toluene fetotoxicity in rats and suggest an effect on exploratory behavior which may be related to hormonal changes in early life. Neuromotor effects of exposure of hamsters to toluene in utero deserve further investigation