831 resultados para offspring
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Observations of the developmental biology of Loxosceles gaucho Gertsch, 1967, the brown spider of southeastern Brazil are scarce. The present study reports the method of individualized rearing of 18 populations of L. gaucho, kept in laboratory under varied diet conditions, and characterizes their nympho-imaginal period as well as factors related to their reproduction. Females built the first egg sac about 20 days after copulation and nymphs hatched 40 days after the laying date. Average offspring was 61.3 spiderlings and females usually built three to four successive egg sacs in a period of five to seven months. First nymphs initiated their predatory activity between the 5th and 8th days after hatching and the majority reached adulthood within six moults (range of five to eight) in approximately 15 to 17 months (male) and 15.5 to 18 months (female). The average sex ratio equaled 1.0:1.7 (male:female). The wide individual variability of this species intermoult intervals is herewith expressed by the intermoult rate, which was fairly uniform for both intra and interpopulations and gives a relevant aspect for a general idea of the life cycles of spiders.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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O organofosforado diclorvós impregnado em coleiras plásticas é um recurso utilizado em medicina veterinária que visa ao controle de ectoparasitas de cães e gatos. O objetivo deste trabalho foi avaliar os efeitos do uso de coleiras plásticas impregnadas com diclorvós (8,37%) em ratas Wistar durante o período de gestação e lactação, como possível fonte de alterações comportamentais e da atividade colinesterásica cerebral dos filhotes. Na desmama, não houve diferença na atividade colinesterásica cerebral entre as mães tratadas com diclorvós e o grupo controle, bem como entre os respectivos filhotes. O tratamento com diclorvós também não influenciou no comportamento geral dos animais, avaliado no campo aberto, nem no nível de ansiedade testado no labirinto em cruz elevado, ambos aos 35 dias pós-natal.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Although the Brazilian sharpnose shark, Rhizoprionodon lalandii (Muller and Henle, 1839), is an inshore species widely distributed in the Western Atlantic from Panama to Uruguay, there is little available information on its biology. During a long-term study of small coastal sharks caught by gill net fisheries in southeastern Brazil (PROJETO CACAO), 3643 specimens of R. lalandii were examined, comprising 61.3% of the total sharks,and including all sizes classes, from 30 to 78,5 cm TL., and weights from 100 to 2950 g. The length-weight relationships were not significantly different between sexes, Overall sex ratio favoured the males slightly at the rate of 1.3: 1. Sex ratios, however, did differ significantly between season and size classes. This species occurred in this area all year long. Three seasonal size-class Occurrence patterns were recognized: (1) between October and March, the juveniles were more frequents (2) from April to July, adults were most common, and (3) from August to September, neonates were most numerically abundant. Such patterns we to associated with reproductive tactics that may reduce intra-specific and inter-specific competition with hammerhead shark neonates (Sphyrna lewini). probably result in reduced natural mortality of the offspring during their first few months. (C) 2005 Elsevier B.V. All rights reserved.
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Lead toxicity was studied in rats exposed from conception until weaning and assessed by monitoring offspring behavior in both the open field and elevated plus maze and by determining tissue lead in an assessment schedule extended to first (F1) and second (F2) generations. Dams utilized for the F1 generation were submitted to 750 ppm of lead (acetate) in drinking water during pregnancy and lactation. For F1 pups, behavioral alterations were not detected in the elevated plus maze, while in the open field, spontaneous locomotor activity as well as time of both grooming and rearing increased, while freezing time decreased in 30- and 90-day-old rats. Lead content was higher in tissues of 1- and 30-day-old pups. However, in 90-day-old rats, lead was detected only in the femur. F2 generation was lead-free but still presented alterations in both locomotor activity and grooming in 30- and 90-day-old pups. It appears that developmental lead exposure may cause behavioral effects during the developmental stage of the F1 generation, which remains throughout the animal's adult life as a sequel, regardless of lead accumulation, and is extended to the F2 generation of rats. (C) 2001 Elsevier B.V. All rights reserved.
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The effects of maternal exposure to lead (Pb) during the perinatal ( 1% and 0.1% Pb) periods of sexual brain differentiation were studied in adult male offspring. Maternal Pb levels were measured after treatment. Behavioral (open field and sexual behavior), physical (sexual maturation, body and organ weights), and biochemical (testosterone levels and hypothalamic monoamine and respective metabolite levels) data were assessed in perinatally exposed offspring. The effects of gonadrotopin-releasing hormone (GnRH) administration to pups at birth on puberty and sexual behavior were also investigated in offspring postnatally exposed to the metal. Results showed that perinatal administration of the two Pb concentrations did not modify maternal weight gain; 1% Pb exposure reduced offspring body weight during the 7 days of treatment while no changes were observed after 0.1% Pb exposure; neither ph concentration altered offspring sexual maturation; the higher Pb concentration improved sexual behavior while the 0.1% concentration reduced it; exposure to 0.1% Pb caused decrease in testis weight, an increase in seminal vesicle weight and no changes in plasma testosterone levels; hypothalamic VMA levels were increased compared to the control group; GnRH administration reversed the effects of 0.1% Ph administration on male sexual behavior. These results show that perinatal exposure to ph had a dose-dependent effect on the sexual behavior of rats and that a decrease in GnRH source in the offspring was probably involved in the reduction of their sexual performance. (C) 2001 Elsevier B.V. All rights reserved.
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Dissection of 286 specimens of the Bothrops neuwiedi pubescens, combined with data on captive individuals, provided information on the reproductive biology of this viperid snake from southern Brazil. Females attained larger body sizes than males, and reproduction was seasonal with mating taking place in autumn when males were more frequently encountered. Vitellogenesis occurred from summer to spring (January-September), sperm storage during autumn and winter (May-September), ovulation and fertilization in early spring (September), embryonic development during middle spring and summer (October-March), and parturition in the summer (January-March). Embryonic development was estimated to last from three to five months, a shorter time than was previously reported. The number of offspring of Bothrops neuwiedi pubescens born in one litter can vary from four to 25 ((x) over bar = 11). Fecundity is correlated with maternal body size. Neonates measure 17-25 cm SVL. Inferred growth rate of juveniles was low (10 mm/month in first year), with males attaining sexual maturity at about 16 months, but maturity is delayed in females for at least two additional years.
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A total of 116 goats originating from three heterozygous bucks for rob (5/15) were cytogenetically studied at Botucatu, Brazil. In the mating 59,XY,t(5/15) x 60,XX, the offspring karyotype proportion did not differ significantly from the expected ratio of 1 normal:1 heterozygous. In the mating 59,XY,t(5/15) x 59,XX,t(5/15) the observed proportion was 1 normal:2 heterozygous:1 homozygous, and in the mating 59,XY,t(5/15) X 58,XX,tt(5/15) the observed proportion was 1 heterozygous:1 homozygous. No animals had unbalanced karyotypes and no differences in the weight at birth of normal, heterozygous and homozygous kids were observed (P > 0.10).
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The effects of prenatal exposure of rat pups to 0.08 mg/kg deltamethrin (DTM) on physical, reflex and behavioral developmental parameters, on forced swimming and open-field behaviors, and on striatal monoamine levels at 60 days of age were observed. Maternal and offspring body weight, physical and reflex development were unaffected by the exposure to the pesticide. At 21 days of age, open-field locomotion frequency and immobility duration of male and female offspring were not different between control and exposed animals. However, male rearing frequency was increased in experimental animals. A decreased immobility latency to float and in general activity after the swimming test in male offspring was observed at adult age; no interference was detected in the float duration during the swimming test. In addition, these animals presented higher striatal 3,4-dihydroxyphenylacetic acid (DOPAC) levels without modification in dopamine (DA) levels and an increased DOPAC/DA ratio. These data indicate a higher activity of the dopaminergic system in these animals. Noradrenaline (NA) levels were increased, while MHPG levels were not detectable in the system studied. Serotonin (5-HT) and 5-hydroxyindolacetic acid (5-HIAA) levels, as well as the homovanillic acid (HVA)/DA ratio, were not modified by the exposure to the pesticide. No changes were observed in swimming and open-field behaviors nor were there any changes in striatal monoamines or their metabolites in the female experimental group. In relation to the pesticide formula, the present data showing that prenatal exposure to DTM alters latency to float and the activity of striatal dopaminergic system might reflect a persistent effect of the pesticide on animal motor activity, mainly in males. on the other hand, the decrease in general activity observed in experimental male rats suggests higher levels of emotionality induced by previous exposure to the swimming behavior test in relation to control animals. Data gathered in the present study may be important for the assessment of the safety of pyrethroid insecticides. (C) 2001 Elsevier B.V. All rights reserved.