Efeitos genéticos e ambientais sobre a idade à primeira concepção de fêmeas suínas

The genetic and environmental factors that affect age at first conception (AFC) of gilts were evaluated, using 466 observations of Dalland animals (C-40). The software program MTDFREML was used to assess the genetic parameters on an animal model that included as fixed effect, contemporary group and, as random effects, the additive genetic, the common litter and the error. Mean value of AFC was 241.12±25.9 days, with CV of 8.5 %. Variance analysis showed that year (P<0.01), season (P<0.01) and herd effects (P<0.01) were important sources of variation of AFC. The throat effect (P=0.34) was not important for the AFC, but the mother of the gilts (P<0.01) was an important source of variation. The heritability estimate was 0.44±0.14 that this trait would yield genetic gain as a response to the selection.

Associação genética da prenhez aos 16 meses com o peso à desmama e o ganho de peso em animais da raça Nelore

Objetivou-se verificar a possibilidade de utilização da prenhez de novilhas aos 16 meses (Pr16) como critério de seleção e as possíveis associações genéticas entre prenhez em novilhas aos 16 meses e o peso à desmama (PD) e o ganho de peso médio da desmama ao sobreano (GP). Foram realizadas análises uni e bicaracterísticas para estimação dos componentes de co-variância, empregando-se um modelo animal linear para peso à desmama e ganho de peso da desmama ao sobreano e não-linear para Pr16. A estimação dos componentes de variância e da predição dos valores genéticos dos animais foi realizada por Inferência Bayesiana. Distribuições flat foram utilizadas para todos os componentes de co-variância. As estimativas de herdabilidade direta para Pr16, PD e GP foram 0,50; 0,24 e 0,15, respectivamente, e a estimativa de herdabilidade materna para o PD, de 0,07. As correlações genéticas foram -0,25 e 0,09 entre Pr16, PD e GP, respectivamente, e a correlação genética entre Pr16 e o efeito genético materno do PD, de 0,29. A herdabilidade da prenhez aos 16 meses indica que essa característica pode ser utilizada como critério de seleção. As correlações genéticas estimadas indicam que a seleção por animais mais pesados à desmama, a longo prazo, pode diminuir a ocorrência de prenhez aos 16 meses de idade. Além disso, a seleção para maior habilidade materna favorece a seleção de animais mais precoces. No entanto, a seleção para ganho de peso da desmama ao sobreano não leva a mudanças genéticas na precocidade sexual em fêmeas.

Análise bayesiana na estimação de correlações genéticas entre escores visuais e características reprodutivas de bovinos Nelore utilizando modelos linear-limiar

Estimaram-se as correlações genéticas entre os escores visuais e as características reprodutivas, utilizando a estatística bayesiana sob modelo animal linear-limiar, em bovinos da raça Nelore. Foram estudadas características categóricas morfológicas, avaliadas visualmente aos oito, 15 e 22 meses de idade; e características contínuas de perímetro escrotal padronizado aos 365 e 450 dias de idade, além da idade ao primeiro parto. As estimativas de correlações genéticas foram de sentido favorável à seleção, apresentando magnitudes moderadas, sugerindo que a seleção de animais para um biótipo desejável pode levar a animais com maior fertilidade e precocidade sexual. As estimativas de correlação genética para o perímetro escrotal padronizado aos 450 dias e a idade ao primeiro parto com as características morfológicas avaliadas aos 22 meses de idade foram maiores do que as obtidas entre as características de escores visuais avaliadas aos oito e 15 meses de idade. A utilização de escores visuais como critério de seleção trará progresso genético também para as características reprodutivas.

Estimação de fatores de correção do perímetro escrotal para idade e peso corporal em touros jovens da raça Nelore

Neste trabalho foram estudados os efeitos de idade e peso sobre o perímetro escrotal (PE) de touros jovens da raça Nelore e estimados os fatores de correção (FC) do PE para esses efeitos. As informações utilizadas pertencem aos Registros de Produção da Associação Paraguaia dos Criadores de Nelore, obtidos entre 1986 e 1997, de 110 criatórios, totalizando 7458 observações. Os coeficientes de regressão que permitiram o cálculo dos FCs para o PE foram estimados pelo método dos quadrados mínimos, empregando-se um modelo que considerou o grupo contemporâneo (animais nascidos no mesmo ano, estação, rebanho, avaliados na mesma data e do mesmo grupo de manejo alimentar na desmama e no sobreano), o efeito linear da idade em dias e os efeitos linear e quadrático do peso aos 570 dias de idade (P570). O efeito da idade sobre o PE foi igual a 0,0383(±0,0024) cm/dia e do P570 sobre o PE corrigido para essa idade, 0,0708(±0,0049) cm/kg, efeito linear, e -0,0000413(±0,0000074) cm/kg², efeito quadrático. A idade e o peso do animal foram importantes fontes de variação a serem removidas do PE, como indicativo da precocidade sexual de touros de sobreano.

Relative development of tissues, commercial meat cuts and live weight components in Saanen goats

Objetivando avaliar o desenvolvimento relativo dos componentes do peso vivo (PV), dos cortes comerciais e dos tecidos da carcaça, utilizaram-se 40 cabritos Saanen. Os animais foram abatidos ao atingir 5,0; 12,5; 20,0; 27,5 e 35,0 kg de PV e a carcaça foi seccionada em paleta, pescoço, 1ª a 5ª costelas, 6ª a 13ª costelas, peito/fralda, lombo e perna. A perna foi dissecada em ossos, músculos e gordura. Utilizou-se a equação alométrica Y=aXb para estimar o desenvolvimento relativo. O crescimento do tecido ósseo foi precoce, o do tecido muscular intermediário e o da gordura crescimento tardio, uma vez que a gordura subcutânea é depositada mais tardiamente. Os cortes comerciais apresentaram coeficiente de alometria isogônico, com exceção do corte da 6ª a 13ª costelas e do peito/fralda. O desenvolvimento da carcaça e dos não-componentes da carcaça acompanhou o peso de corpo vazio. Cabritos com 35 kg de PV possuem proporção de músculos e relação músculo:osso adequadas, mas apresentam proporção de gordura maior que a observada nos animais abatidos com 20 kg de PV.

Genetic and environmental effects on age at first farrowing in sows in southeastern Brazil

We evaluated genetic and environmental factors affecting age at first farrowing of sows in the Brazilian southeast. For this purpose, 466 observations regarding the age at first farrowing were made for Dalland-C40 (c) animals belonging to two herds. The effects of the environmental factors on this trait were assessed by means of a model that included, as random effects, the influence of the sow's father and mother and, as fixed effects, the influence the year of birth, the herd and the birth season, along with the covariable litter size at birth. The variance components were estimated using the derivative-free restricted maximum likelihood method. The estimated mean was 354.8 +/- 25.87 days, with a coefficient of variation of 7.29%. Significant effects on the trait were observed for the herd, the year and the season of birth; but a linear effect of litter size at birth on the age at first farrowing was not observed. The boar did not significantly contribute to the variation occurring among the sows, whereas the sow's mother caused significant variation. The heritability estimate for the age at first farrowing was 0.44 +/- 0.15, which is considered high. We concluded that herd effect and year and season of birth should be taken into consideration for an accurate genetic comparison; consequently, the animals should be joined into contemporary groups.

Avaliação de cultivares de pepino tipo caipira sob ambiente protegido em duas épocas de semeadura

Avaliaram-se sob cultivo protegido na Fazenda Experimental São Manuel (FCA/UNESP, Câmpus de Botucatu) quatro variedades (Branco Colonião, Caipira Hortec, Prêmio e Rubi) e três híbridos (Caipira AG-221, Guarani AG-370 e Safira) de pepino tipo caipira em duas épocas: verão e inverno. O delineamento experimental foi o de blocos ao acaso, com quatro repetições e cinco plantas por parcela. O híbrido Safira foi o mais produtivo na semeadura de verão (41,3 frutos por planta), enquanto no inverno `Prêmio' produziu menor número de frutos comercias (6,7 frutos por planta) que todos os demais. Iniciaram-se as colheitas, em média, 51 e 87 dias após a semeadura no verão e no inverno respectivamente. Os híbridos foram mais precoces que as variedades na semeadura de verão. Os frutos passavam do ponto mais rapidamente no cultivo de verão, apresentando maior massa média. Concluiu-se que o híbrido Safira foi o melhor para o cultivo no verão, enquanto no inverno a produtividade de todas as cultivares foi muito prejudicada.

Caracterização comportamental endócrina das fases ontogenéticas de sagüi comum (Callithrix jacchus)

The use of animal models in biomedical research is ever increasing. Models that use primates might also have advantages in terms of low maintenance costs and availability of biological knowledge, thereby favoring their use in different experimental protocols. Many current stress studies use animal models at different developmental stages since biological response differs during ontogeny. The aims of this study were to perform a detailed characterization of the developmental stages of common marmosets (Callithrix jacchus), a very important animal model used in biomedical research. Ten subjects, 6 females and 4 males, were followed from birth to initial adult age (16 months). Behavioral and fecal collection for measurement of adrenal (cortisol) and sex (progesterone, estradiol and androgens) hormones took place twice a week during the first month of life and once a week for the remainder of the study. Behavior was observed for 30 minutes in the morning (0700-09:00h) and afternoon (12:00-14:00h). Behavioral profile showed changes during ontogeny, characterizing the 4 developmental stages and the respective phases proposed by Leão et al (2009).. Differentiation of developmental stages was considered using the onset, end, change and stabilization of the behavioral profile parental care (weaning and carrying), ingestion (solid food), affiliation (social grooming) and autogrooming, agonism (scent marking and piloerection) and play behavior and endocrine profile. Infant weaning and carrying terminated within the infantile stage and the peak of solid food ingestion was recorded in the infantile III phase. Receiving grooming was recorded earlier than grooming performed by the infant and autogrooming. The first episode of scent marking was recorded in the 4th week and it was the least variable behavior, in terms of its onset, which, in almost all animals, was between the 5th and 7th week of life. Solitary play and play with the twin started around the 7th week and play with other members of the group started 8 weeks later. Sex hormone secretion started to differ from basal levels between the 21st and 23rd week of life, in males and females, suggesting that puberty occurs simultaneously in both sexes. Basal cortisol, even at an early age, was higher in females than in males. However, cortisol was not correlated with the juvenile stage, as expected, since this stage corresponds to the transition between infancy and adult age and most behaviors are intensified by this time. The behavioral and endocrine profile of subadult animals did not differ from that of the adults. These results provide more detailed parameters for the developmental process of C. jacchus and open new perspectives for the use of experimental approaches focused on the intermediate ontogenetic phases of this species

Ritmo circadiano de atividade motora e distribuição diária dos comportamentos afiliativos ao longo da fase juvenil em saguis (callithrix jacchus)

The temporal allocation of the active phase in relation to light and dark cycle (LD) changes during puberty in humans, degus, rats and rhesus. In marmosets, the animal model used in several biomedical researches, there is evidence of a delay at the beginning of the active phase and an increase in total daily activity after onset of puberty. However, as this aspect was evaluated in animals maintained in natural environmental conditions, it was not possible to distinguish between the effects of puberty and of seasonality. Furthermore, as motor activity is the result of different behaviors in this species, it is also important to characterize the diurnal distribution of other behaviors in juvenile stage. With the aim of characterizing the circadian rhythm of motor activity and the diurnal profile of affiliative behavior in marmosets, the motor activity of 5 dyads juveniles between 4 and 12 months of age and their parents was recorded continuously for actímetro. The families were maintained under artificial LD 12:12 h, constant temperature and humidity. The duration of grooming behavior, proximity and social play among juveniles was recorded 2 times a week in sessions of 15 minutes each hour of the active phase. Afetr onset of puberty in juvenile, it was observed that there was no change in the parameters of circadian motor activity rhythm which were common to most animals. Despite the absence of pubertal modulation, it was observed that the circadian activity profiles have stronger synchrony between individuals of the same family than that of different families, which may indicate that the circadian activity rhythm was modulated by the dynamics of social interactions. In relation to age, the total daily activity and the ratio between evening and morning activity (EA/MA) were higher in juveniles than in adults, which may be associated with differences in the circadian timing system between age groups. Furthermore, the onset of the 10 consecutive hours of higher activity (M10) occurred earlier in adult males than in other members of the group, probably as a way to avoid competition for resources in one of the first activities of the day that is foraging. During the juvenile stage, there was an increase in total daily activity that may be associated with increased motor ability of juveniles. In addition to the circadian activity rhythm, the daytime profile of proximity and social play behaviors was similar between the 5th and 12th month of life of juveniles, in which the interval between 7- 10 h in the morning showed the highest values of proximity and lower values of play social. Moreover, the duration of the grooming showed a similar distribution to adults from the 8th month, wherein the higher values occurring at the interval between 11 14 h of day. Considering the results, the parameters of the circadian activity rhythm had a greater influence of social factors than puberty. In relation to age, there were no changes related to the allocation of the active phase in relation to the LD cycle, but total daily activity, the ratio AV/AM and the start of the M10 is possible to observe differences between juveniles and adults

Caracterização do ritmo de atividade motora durante a puberdade em sagüis (Callithrix jacchus) sob condições semi-naturais

Most of ontogenetic studies on circadian timing system have been developed on infants, adults and elderly. The puberty has not been a stage of life few studied, except for researches in human adolescents, that presents phase delay in sleep-wake cycle. However, few studies have focused on the basis of this circadian change due to methodological difficulties. Thus, an animal model to study the sleep-wake cycle at puberty is essential. In the common marmoset, a social primate, the circadian activity periodicity stabilizes around 4 months (juvenile stage) and the 8h period component has a seasonal variation. Puberty stage of this species begins near the 8th month of age in males and near the 7th month in females with 7 months of duration. With the aim to characterize the circadian motor activity rhythm during puberty in marmosets (Callithrix jacchus) the motor activity was continuous registered by actiwatches in 6 animals between 5-12 months. Since the social factor influence the behavior of this specie, behavioral observations were realized in 30 minutes windows twice/week to a general evaluation of the influence social interactions dynamic across experiment. Determination of puberty onset was done by fecal progesterone and estrogens in females, and androgens in males. From the analysis of the multiple regression test was selected a model that evaluate age and seasonal variables effect on the activity rhythm according to the higher explanation coefficient. The total activity was the only parameter influenced by age. Moreover, the activity onset was the parameter more explained by the model, and the sunrise was the factor that most influenced it. After the puberty onset, 2 dyads advanced the activity onset. The activity total decreased in 1 dyad and increased in 2 dyads. This increase may be related to the birth of infants in these families. The motor activity circadian component stabilized later in 1 dyad, coinciding with the puberty onset of these animals, while bimodality, caused by the 8 h component, was modulated by seasonality. The agonistic behavior was not evaluated due to reduced number of events. There were changes across ages in affiliative behavior of contact in 1 dyad, grooming done in 1 animal and grooming received in 2 animals. Although there is evidence of puberty effect on the activity motor rhythm, the photoperiodic fluctuations influenced the rhythm. Therefore is not possible to affirm if the puberty modulate the activity rhythm in marmosets

Estudo da preferência manual durante o desenvolvimento ontogenético em sagüi comum ( Callithix jacchus)

The study of manual preference is a widely used approach to investigate cerebral laterality in nonhuman primates. However, in New World primates, little is known about the ontogenesis of hand use asymmetry, in both forced and spontaneous activities, as well as how they correlate with sexual hormones. Accordingly, a longitudinal study was conducted on the manual preference of 6 female and 4 male common marmosets (Callithrix jacchus). The study included the record of forced tests to reach for the food using only one hand (forced activity) and activities such as grooming (auto and social), scratching, grasping the food and hanging, in weekly sessions from the infantile (4 months) to the early adult phase (15 months). Feces samples were also collected, at least once a week, to evaluate the level of gonadal steroids and their influence on these behaviors. In the forced activity, the results confirm the influence of the development period on manual preference during feeding, shown by the increase in lateral stability when grasping the food between the juvenile and adult phases. During this period, a sexual hormone effect on development was also observed, mainly of progesterone in females and androgen in males, but no difference between sexes was found. In the females, progesterone also influenced the manual preference index, with a proportional increase in the degree of manual asymmetry during puberty. With respect to spontaneous activities, the animals showed proportional use of both hands when scratching, hanging, holding the food and grooming. A positive correlation was also found between the preference for holding the food in forced activities and in spontaneous activities

A escola enquanto espaço privilegiado de construção de "meninos de verdade" :concepções e valores atribuidos a essa instituição por crianças pobres

The intention of this study was to identify the school conception (conceptions) in the discourse of poor children. There were inquired two groups of subjects: the first was composed of children that inserted precociously themselves into the work market and must to go to school because they take part in one of the governmental programs, called, minimum income programs. The second will be composed of children that live in the poorest district in Natal/RN city. And don´t have obligatoriness to go to school. Thus, thematics like precocious work, minimum income program, capitalism, neoliberalism was aproached in our discussion. We also intended to make a illustrate with Pinochio Adventures fable, because its conception school is similar like real official discourse school from everybody. In cited narrative, the character Gepeto didn t know what s a truth child but knows that exist a place in city where his maledoll Pinochio would be one the school. Thus, this institution was destine by the justice and politics from Gepetos s city how children right. Pinochio, in the book s end, to be transformed himself in a truth child because learned in school responsible and goodness behaviors. To uphold our inquiry we used the Content Analysis and socio-historical perspectives. The result showed that the children know that exist differents schools: yours and other, to rich class. Their school is admited like good, it is a study place, it isn´t disorders place; and also make propotional to social ascencion. The children s discourses is similar to capitalism s discourse

Épocas de la aplicación de desecantes en el cultivo de la soja: tenor de agua y productividad

Los herbicidas glifosato y paraquat son utilizados por los productores de soja con el objetivo de desecar las plantas, anticipar y uniformizar la cosecha. Sin embargo, el uso indiscriminado de herbicidas puede causar problemas eventualmente en las características agronómicas y fisiológicas del cultivo. El presente trabajo tuvo por objetivo evaluar la utilización de los herbicidas glifosato y paraquat como desecantes para el cultivo de la soja. El experimento fue llevado a cabo en el año agrícola 2005/06, en un delineamiento experimental de bloques al azar, con cuatro repeticiones. Los tratamientos fueron dispuestos en dos esquemas factoriales, 3x3x5x2 y 3x2x5x2: dos desecantes (glifosato y paraquat) y un testigo (sin desecación), aplicación de los desecantes en tres y dos estadios fenológicos de las plantas (R6, R7 y R8) y (R7 y R8), para las variedades MSOY 6101 de ciclo superprecoz, y MG/BR 46 (Conquista) de ciclo precoz, respectivamente, cinco épocas de muestreo (2; 4; 6; 8 y 10 días después de la aplicación) y evaluación en dos posiciones en la planta (ápice y base). Fue evaluada la producción de semillas, masa y tenor de agua de 100 semillas. Los desecantes evaluados fueron eficientes en la reducción del tenor de agua de las semillas, sin afectar la productividad y la masa de 100 semillas.

Impacto da ingestão de cálcio sobre a mineralização óssea em adolescentes

A puberdade destaca-se como período fundamental para a aquisição de massa óssea. Durante essa fase da vida, a mineralização encontra-se aumentada com taxas de formação óssea superior às de reabsorção. Nesse sentido, o objetivo desta revisão foi investigar a inter-relação da ingestão dietética de cálcio com a mineralização óssea, durante a puberdade. Entre os fatores influenciadores nutricionais, merecem destaque o fosfato e o magnésio, que, juntamente com o cálcio, mantêm a integridade estrutural do esqueleto. A revisão de literatura indicou que os excessos de proteína e de refrigerantes, na alimentação dos jovens, acarretam comprometimento na mineralização óssea, embora os dados sejam ainda contraditórios. Conclui-se que, durante o período da puberdade, é indicado manter o aporte de cálcio em níveis adequados, na perspectiva de maximizar o pico da massa óssea.

Significance of large nuclear vacuoles in human spermatozoa: implications for ICSI

The aim of this study was to determine the extent of DNA fragmentation and the presence of denatured single-stranded or normal double-stranded DNA in spermatozoa with large nuclear vacuoles (LNV) selected by high magnification. Fresh semen samples from 30 patients were prepared by discontinuous isolate concentration gradient. Spermatozoa with normal nucleus (NN) and LNV were selected at x8400 magnification and placed on different slides. DNA fragmentation was determined by TUNEL assay. Denatured and double-stranded DNA was identified by the acridine orange fluorescence method. DNA fragmentation in spermatozoa with LNV (29.1%) was significantly higher (P < 0.001) than in spermatozoa with NN (15.9%). Therefore, cleavage of genomic DNA in low molecular weight DNA fragments (mono- and oligonucleosomes), and single-strand breaks (nicks) in high molecular weight DNA occur more frequently in spermatozoa with LNV. Similarly, the percentage of denatured-stranded DNA in spermatozoa with LNV (67.9%) was significantly higher (P < 0.0001) than in spermatozoa with NN (33.1%). The high level of denatured DNA in spermatozoa with LNV suggests precocious decondensation and disaggregation of sperm chromatin fibres. The results show an association between LNV and DNA damage in spermatozoa, and support the routine morphological selection and injection of motile spermatozoa at high magnification for ICSI.