Association between heart rate, heart rate variability, cortisol, glucose and electrolytes in healthy newborn calves / Associação entre frequência cardíaca, variabilidade da frequência cardíaca, cortisol, glicose e eletrólitos em bezerros recém-nascidos saudáveis

This study aims at evaluating the effects of electrolytes, glucose and cortisol levels over heart rate (HR) and heart rate variability (HRV) in healthy newborn calves. Seventeen healthy Holstein calves were evaluated during their first month of life, and the plasma concentrations of glucose, cortisol, calcium, magnesium, inorganic phosphorus, sodium and potassium were analyzed. HRV indexes were determined in the time and frequency domains through the analysis of neonatal electrocardiogram recordings. In the first day, low blood levels of phosphorus presented a strong correlation with the HR and the increased high-frequency components of HRV. The plasma concentrations of magnesium decreased significantly throughout the 35 days, revealing a positive association with a decreasing low-frequency components of HRV at day 28. There was a strong correlation between HR, HRV indexes, some plasma electrolytes, glucose and cortisol during the studied period. Variations in the concentrations and correlations observed may be attributed to the adaptive neonatal period in calves.(AU)

Este estudo teve como objetivo avaliar os efeitos dos níveis de eletrólitos, glicose e cortisol sobre a frequência cardíaca (FC) e a variabilidade da frequência cardíaca (VFC) em bezerros recém-nascidos e saudáveis. Dezessete bezerros da raça Holandesa foram avaliados durante o primeiro mês de vida e foram analisadas as concentrações plasmáticas de glicose, cortisol, cálcio, magnésio, fósforo inorgânico, sódio e potássio. Os índices VFC foram determinados em domínios de tempo e frequência por meio da análise de gravações do eletrocardiograma neonatal. No primeiro dia, baixos níveis sanguíneos de fósforo correlacionaram-se fortemente com FC e aumento dos componentes de alta frequência da VFC. As concentrações plasmáticas de magnésio diminuíram significativamente ao longo dos 35 dias, revelando correlação positiva com a diminuição dos componentes de baixa frequência da VFC no dia 28. Houve uma forte correlação entre FC, índices de VFC, eletrólitos plasmáticos, glicose e cortisol durante o período estudado. As variações nas concentrações e correlações observadas podem ser atribuídas ao período neonatal adaptativo em bezerros.(AU)

Glucose and insulin curve in pregnant mares and its relationship with clinical and biometric features of newborn foals / Curvas de glicose e insulina em éguas gestantes e sua relação com as características clínicas e biométricas dos neonatos

The aim of the present study was to describe the dynamics of glucose and insulin curves in pregnant mares, and to evaluate the curves according to body condition score, identifying the presence of insulin resistance and correlating these values ​​with the weight, height and clinical changes of the neonates. For this, pregnant mares were evaluated and then grouped according to body condition score during the gestation length until lactation. GrM corresponds to mares with moderate body score (BCS 5-6); GrOv were mares with overweight body score (BCS 7) and GrOb were obese mares (BCS 8-9). A two-step oral sugar test (OST) was used to determine the data. Cortisol analysis was performed with 300-320 days of gestation, at foaling and after parturition. For evaluation of the neonate, a general clinical examination and, weight and height measurements were performed. The results showed hyperglycemia in response to OST with normal insulin values at foaling with a subsequent fall in both values at lactation disregarding group division. Baseline glucose was decreased in GrM compared to GrOv and GrOb with 70-100 days of gestation and with 130-160 days of gestation. With 270-300 days of gestation and post-partum GrOb had increased baseline glucose than GrM. After OST, glucose at foaling day in GrOb presented increased values than GrM. Baseline insulin values did not differ between groups. Post OST insulin levels were higher in GrOb than GrM and GrOv at parturition. No difference in cortisol between moments was identified. GrOb and GrOv maintained increased concentrations after foaling while GrM had a decrease. No correlation was found between maternal glucose and insulin values with foal weight and height, however, a lower ratio between neonatal weight and mare's weight in GrOb and GrOv was identified in relation to the GrM. At foaling, mares presented glucose dysregulation, with obese and overweight mares presenting a greater response to OST.(AU)

O objetivo do presente estudo foi descrever a dinâmica das curvas de glicose e insulina em éguas gestantes e avaliar as curvas de acordo com o escore de condição corporal, identificando a presença de resistência insulínica e correlacionando esses valores com o peso, altura e alterações clínicas dos neonatos. Para isso, as éguas prenhes foram avaliadas em conjunto e agrupadas de acordo com o escore de condição corporal durante a gestação até o pós-parto. GrM pertenciam éguas com escore corporal moderado (EC 5-6); GrOv, grupo de éguas com escore corporal acima do peso (EC 7) e GrOb, grupo de éguas obesas (EC 8-9). O teste de glicose oral em duas etapas (OST) foi usado para determinar os dados. A análise do cortisol também foi realizada nos 300-320 dias de gestação, no dia do parto e após o parto. Para avaliação do neonato, foram realizados exame clínico geral e medidas de peso e altura. Os resultados mostraram hiperglicemia em resposta ao OST com valores normais de insulina no momento parto, com uma queda subsequente em ambas as variáveis na lactação, desconsiderando a divisão do grupo. A glicemia basal diminuiu no GrM em comparação com GrOv e GrOb com 70-100 dias de gestação e com 130-160 dias de gestação. Com 270-300 dias de gestação e no pós-parto, o GrOb apresentou aumento na glicemia basal em relação ao GrM. Após OST, a glicose no dia do parto no GrOb apresentou valores aumentados em relação ao GrM. Os valores basais de insulina não diferiram entre os grupos. Após OST níveis de insulina foram maiores no GrOb do que GrM e GrOv no momento do parto. Não houve diferença nos valores de cortisol entre os momentos. O GrOb e GrOv mantiveram cortisol aumentado após o parto enquanto o GrM diminuiu. Não foi encontrada correlação entre os valores de glicemia e insulina materna com o peso e a altura do potro, entretanto, foi identificada uma relação menor entre o peso neonatal e o peso da égua no GrOb e GrOv em relação ao GrM. No parto, as éguas apresentaram desregulação da glicose, sendo que as éguas obesas e com sobrepeso apresentaram uma resposta maior ao OST.(AU)

Response of vital functions, Apgar and cortisol in the prognosis of vigor against neonatal factors of lambs / Resposta das funções vitais, de Apgar e cortisol no prognóstico de vigor frente a fatores neonatais de cordeiros

The management of lambs during the neonatal period has been studied in several researches due to the vital and hormonal organic adaptations undergone by the calf after birth. However, gender, number of pups and type of delivery play an important role in understanding neonatal vigor. The study of these groups with the monitoring of clinical evolution and cortisol metabolism becomes an indispensable subsidy for a better understanding of this neonatal phase, aiming to minimize the losses generated. The objective of this study was to evaluate the influence of gender, number of pups and type of delivery in the prognosis of neonatal vigor of lambs through clinical and cortisol diagnosis. Thirty crossbred Santa Inês lambs with Dorper in the neonatal phase were divided into three groups: male and female, number of pups (single and twin) and type of delivery (eutocic and dystocic). In each group, clinical evaluation of heart and respiratory rate, rectal temperature, Apgar score and weight were performed; and with the exception of cortisol, all evaluations were performed at fifteen and sixty minutes, as well as at twelve and twenty-four hours. In addition, blood samples were collected for cortisol dosage obtained in two moments at fifteen and sixty minutes using the radioimmunoassay technique. Among the three experimental groups related to lamb vigor, the heart rate was the only one that showed lower mean values (P<0.05) at twenty-four hours in the male group 90.00±20.20bpm, twins 96.44±20.02bpm and eutocic 93.25±18.11bpm. Differences in respiratory rate values were observed in the eutocic group (64.00±14.75mpm) at twenty-four hours. In the group of males there was a significant reduction in body temperature during the evaluation moments (P<0.05). Lambs from the group of twins showed lower body weight during the evaluations. At both times the analysis of serum cortisol was less than at sixty minutes. It was concluded that soon after the birth there were marked changes in the physiological parameters and weight of Santa Inês lambs, but were not enough to cause negative effects on the vigor of the neonates, indicating the occurrence of effective neonatal adaptation capacity in this species.(AU)

O manejo dos cordeiros durante o período neonatal tem sido objeto de estudo em diversas pesquisas devido às adaptações orgânicas vitais e hormonais sofridas pela cria após o parto. Todavia, o gênero, número de filhotes e o tipo de parto parecem desempenhar um papel importante para melhor compreensão do vigor neonatal. Além disso, o estudo destes grupos com o acompanhamento da evolução clínica e do metabolismo do cortisol torna-se um subsidio indispensável para melhor compreensão dessa fase neonatal, visando minimizar as perdas geradas. Dessa forma, o objetivo do presente trabalho foi avaliar a influência do gênero, número de filhotes e tipo de parto na apresentação do vigor neonatal dos cordeiros através do diagnostico clinico e de cortisol. Foram utilizados trinta cordeiros mestiços da raça Santa Inês com Dorper em fase neonatal divididos em três grupos: gênero (macho e fêmea), número de filhotes (único e gemelar) e tipo de parto (eutócico e distócico). Em cada grupo, foi realizada a avaliação clínica da frequência cardíaca e respiratória, temperatura retal, escore Apgar e peso; e com a exceção do cortisol, todas as avaliações foram realizadas aos quinze e sessenta minutos, como também às doze e vinte e quatro horas. Adicionalmente, procedeu-se com a coleta de amostras de sangue total para dosagem de cortisol obtida em dois momentos aos quinze e sessenta minutos através da técnica de radioimunoensaio. Dentre os três grupos experimentais relacionados com vigor dos cordeiros, a frequência cardíaca foi a única que evidenciou menores médias (P<0,05) às vinte e quatro horas no grupo dos machos 90,00±20,20bpm, gêmeos 96,44±20,02bpm e eutócicos 93,25±18,11bpm. Observou-se no grupo eutócico diferenças nos valores da frequência respiratória de 64,00±14,75mpm às vinte e quatro horas. No grupo dos machos houve redução significativa na temperatura corpórea durante os momentos de avaliação (P<0,05). Cordeiros do grupo de gêmeos demonstraram menor peso corpóreo durante as avaliações. Em ambos momentos a análise do cortisol sérico demonstrou se menor aos sessenta minutos. Pôde se concluir que logo após o parto ocorreram alterações marcantes nos parâmetros fisiológicos e peso de cordeiros Santa Inês, porém não foram suficientes para causar efeitos negativos sobre o vigor dos neonatos, indicando a ocorrência de efetiva capacidade de adaptação neonatal nesta espécie.(AU)

DNA damage in Wistar Kyoto rats exercised during pregnancy

Abstract Purpose: To evaluate DNA damage levels in pregnant rats undergoing a treadmill exercise program. Methods: Wistar Kyoto rats were allocated into two groups (n= 5 animals/group): non-exercise and exercise. The pregnant rats were underwent an exercise protocol on a treadmill throughout pregnancy. Exercise intensity was set at 50% of maximal capacity during maximal exercise testing performed before mating. Body weight, blood pressure and glucose levels, and triglyceride concentration were measured during pregnancy. At day 10 post-natal, the animals were euthanized and maternal blood samples were collected for DNA damage. Results: Blood pressure and glucose levels and biochemical measurements showed no significant differences. Increased DNA damage levels were found in exercise group compared to those of non-exercise group (p<0.05). Conclusion: The exercise intensity protocol used in the study might have been exhaustive leading to maternal increased DNA damage levels, demonstrating the relevance of an adequate protocol of physical exercise.

Comparative analysis of two different models of swimming applied to pregnant rats born small for pregnant age

ABSTRACT The aim of this study was to compare two models of swimming applied to pregnant rats born small for pregnancy age (SPA). Diabetes was chemically induced in adult female rats to develop an inadequate intrauterine environment, leading to birth of a SPA offspring. In adulthood, the female SPA rats were mated and submitted to different swimming programs. The exercise program 1 (Ex1) consisted of swimming for 15 minutes, followed by 15 minutes of rest and another 15 minutes of swimming, 3 days a week before and during pregnancy. Another program (Ex2) was applied during 60 minutes uninterrupted a day, 6 days/week during pregnancy. The pregnant rats presented no interference on body weight and glycemia. The rats submitted to Ex2 model showed decreased insulin and blood glucose levels by oral glucose tolerance test, and reduction in area under curve values. The offspring from dams submitted to both exercise protocols presented an increased rate of newborns SPA. However, the offspring from Ex2 dams showed percentage twice higher of newborns SPA than Ex1 offspring. Our data suggests that continuous exercise of 60 min/day ameliorated the enhanced peripheral insulin sensitivity in growth-restricted females. However, this protocol employed at pregnancy leads to intrauterine growth restriction.

Nesting and neonates of the yellow-spotted river turtle (Podocnemis unifilis, Podocnemididae) in the Araguari River basin, eastern Amazon, Brazil / Nidificação e neonatos de tracajá (Podocnemis unifilis, Podocnemididae) na bacia do Rio Araguari, Amazônia oriental, Brasil

Predation and alteration of microhabitats may represent high risk for nesting of Amazonian turtles. This study aimed at investigating the nesting and body parameters of neonates of Podocnemis unifilis in the Araguari River basin, State of Amapá, Brazil. The spawning sites of this turtle were monitored along the Falsino River (a region with two reserves) and in the urban area of the Porto Grande city along the Araguari River, from August to December 2011. A total of 180 nests were found and the nesting occurred from September to November, with prevalence in October. Eggs hatching occurred in December. The mean incubation period was 63.5 ± 5.2 days and the eggs hatching success was 25%. However, approximately 80% of the nests had suffered predation mainly by humans, which occurred in both the protected areas of the reserves and the urban area. The pattern of nesting site choice was discussed. Egg size was larger than that previously described for the same turtle species in the other regions. The body condition index of neonates indicated a good use of vitelline reserves. The results indicate the urgent need for strategic actions to conserve and maintain the natural stocks of this relatively vulnerable turtle in the region.

A depredação e alterações do micro-hábitat podem representar grande risco para a nidificação de tartarugas amazônicas. Assim, este estudo investigou a nidificação e características corporais de neonatos de Podocnemis unifilis na bacia do Rio Araguari, estado do Amapá (Brasil). Foram monitorados os locais de desova dessa tartaruga no Rio Falsino (região de duas reservas) e na área urbana da cidade de Porto Grande, no período de agosto a dezembro de 2011. Foi encontrado um total de 180 ninhos e a nidificação ocorreu de setembro a novembro, mas a maioria ocorrendo em outubro. A eclosão dos ovos ocorreu em dezembro e o tempo médio de incubação foi 63,5 ± 5,2 dias, com sucesso de eclosão de 25%. Porém, cerca de 80% dos ninhos sofreu predação causada principalmente pelo homem, tanto nas áreas protegidas das reservas como na área urbana. O padrão de escolha dos locais de nidificação observado foi discutido. O tamanho dos ovos foi maior que os descritos previamente para essa mesma espécie de tartaruga em outras regiões. O índice de condição corporal dos neonatos indicou um bom uso das reservas vitelínicas. Os resultados indicam a urgente necessidade de ações estratégicas para conservação e manutenção dos estoques naturais dessa tartaruga com relativa vulnerabilidade na região.

Hemograma e proteínas de fase aguda de bezerros sadios do nascimento aos 30 dias de idade / Hemogram and acute phase proteins of healthy calves from birth to one month old

O conhecimento da dinâmica das alterações nos parâmetros hematológicos e na cinética das proteínas de fase aguda em animais saudáveis nas primeiras semanas de vida é essencial para a interpretação correta dessas avaliações em situações de morbidez e para diferenciar animais sadios e enfermos de forma confiável. Com o intuito de avaliar a cinética desses parâmetros no primeiro mês de vida de bezerros de corte sadios, filhos de vacas primíparas ou pluríparas, amostras de sangue foram coletadas antes da ingestão de colostro e 1, 2, 7, 15 e 30 dias após o nascimento. Os parâmetros eritrocitários foram influenciados pelo número de partos das vacas e o leucograma mostrou alterações características de influência do cortisol fetal liberado por ocasião do nascimento. O teor sérico de proteína total aumentou significativamente após a ingestão do colostro. As concentrações de ceruloplasmina, haptoglobina e proteínas de pesos moleculares 33 kDa e 23 kDa aumentaram significativamente no primeiro dia de vida, seja pela resposta ao nascimento ou pela ingestão do colostro, enquanto os teores de transferrina, albumina e α1-glicoproteína ácida mantiveram-se relativamente estáveis nos primeiros dias de vida, aumentando gradualmente até os 30 dias de idade.

The knowledge of the dynamic in changes of hematologic parameters and the acute phase proteins kinetics in healthy animals in the first weeks of life is essential for the accurate interpretation of these evaluations in morbidity situations, and to reliably differentiate healthy from sick animals. The aim of the study was to evaluate the dynamic of these parameters in the first month of life of healthy beef calves, born from primiparous or multiparous cows, and so blood samples were collected before colostrum intake and 1, 2, 7, 15 and 30 days thereafter to evaluate hemogram and serum proteinogram. The red cell parameters were influenced by the parturition number of cows, and the leukogram showed characteristic changes of the release of fetal cortisol at birth. The total protein level significantly increased after colostrum intake. The concentrations of acute phase proteins ceruloplasmin, haptoglobin and proteins of molecular weight 33 kDa and 23 kDa significantly increased in the first day of life, influenced either by response to birth or colostrum intake, while the levels of transferrin, albumin and α1-acid glycoprotein were relatively stable in the first days, increasing gradually until 30 days of life.

Los huevos falsos (SAGs) facilitan el comportamiento social de emergencia en las crías de la tortuga laúd Dermochelys coriacea (Testudines: Dermochelyidae)

False eggs (SAGs) facilitate social post-hatching emergence behaviour in Leatherback turtles Dermochelys coriacea (Testudines: Dermochelyidae) nests. Hatchling emergence to the beach surface from deep sand nests occurs without parental care. Social behaviour among siblings is crucial to overcome this first challenge in sea turtles life. This study, carried out at the Caribbean coast of Colombia, describes the emergence social behaviour of hatchlings from eight nests, and assess the nests translocation effects on temporal patterns of emergence. For the first time, we propose that space released by dehydration of shelled albumen globes (SAGs) at the top of the clutch, might be a reproductive advantage, while facilitating neonates to group together in a very limited space, and favouring the synchrony of emergence. The mean time of groups emergence was of 3.3 days, varying between 1 and 6 days. We found that relocation of the nests did not significantly affect the temporal pattern of emergence, which was mainly nocturnal (77.7% of natural nests and 81.7% of translocated ones). The maximum number of emergences to the surface occurred at the lowest air temperatures (22:00h-06:00h). The selective advantage of this pattern is probably related to the greater rate of predation and mortality by hyperthermia observed during the day. Rev. Biol. Trop. 58 (3): 943-954. Epub 2010 September 01.

La emergencia de las crías de tortuga laúd eclosionadas en los nidos profundos desde la arena hasta la superficie de la playa ocurre sin ayuda parental y es el primer gran desafío de supervivencia en su ciclo de vida. Este estudio, desarrollado en la costa Caribe colombiana, describe el comportamiento social de emergencia de neonatos y evalúa el efecto de la traslocación de los nidos en los patrones temporales de emergencia. Se propone por primera vez que el espacio liberado por la deshidratación de falsos huevos (SAGs) en la nidada, representa una ventaja reproductiva al facilitar el agrupamiento de los neonatos en un espacio muy limitado y favorecer la sincronía de la emergencia. El tiempo medio registrado para la emergencia en grupo fue de 3.3 días, variando entre uno y seis días. La traslocación de los nidos no afectó el patrón temporal de emergencia que fue predominantemente nocturno (77.77% en nidos naturales y 81.65% en trasladados). Los picos máximos de emergencias a la superficie coincidieron con los periodos de menor temperatura ambiental exterior (22:00h-06:00h). La ventaja selectiva de este patrón temporal y de la emergencia sincrónica está probablemente relacionada con las mayores tasas de depredación y mortalidad por hipertermia observadas durante el día.

Chronobiologic blood pressure assessment: Maturation of the daily rhythm in newborn foals

Circadian rhythmicity of physiological processes in animals has been described for some variables. In order to investigate the daily rhythmicity of blood pressure, seven foals (Equus caballus) were used for 40 days after birth. Measurements of blood pressure were done by means of an oscillometric apparatus (Argus TM-7, Schiller, Barr Switzerland) with the foals in a standing position and the cuff placed around the tail. Blood pressure was recorded twice a day, 1 hour before dawn and 1 hour before dusk for the first 10 days of life, every 2 days from the 11th to the 32nd day, on the 36th and on the 40th day. Two-way repeated measures analysis of variance (ANOVA) were used to determine statistically significant differences between the mean values recorded at dawn and dusk during the study. Analysis of variance showed a significant effect of time (p<0.0001), during the first 40 days of life. This study confirms a strong correlation between age and blood pressure in horse and the absence of blood pressure maturation in foals 40 days old. The results on the maturation of the daily rhythm of blood pressure in foals is a contribution to the study of the development of circadian rhythms in mammals. These results are also useful for the chronophysiological assessment of blood pressure in the horse.

Programação neonatal do perfil lipídico em ratos e ovelhas / Neonatal programming to lipids profile in rats and sheeps

A nutrição na lactação é um importante fator de impressão para futuras alterações hormonais e metabólicas no desenvolvimento, que vai regular a composição corporal, a homeostase glicêmica e o perfil hormonal dos animais, caracterizando o processo de programação. Nesta etapa crítica da vida, a desnutrição ou o excesso de nutrientes modificam a secreção e ação de vários hormônios, especialmente a prolactina, leptina e hormônios tireóideos. Apesar dos diversos estudos epidemiológicos mostrando que o perfil lipídico pode ser programado por alterações nutricionais na gestação e lactação, contribuindo para maior risco de doenças cardiovasculares, poucos estudos exerimentais foram realizados. Assim, avaliamos a programação do perfil lipídico em diversos modelos de impressão nutricional e hormonal em ratos e ovelhas, relacionando a programação da massa e composição corporal e homeostase glicêmica. Estudamos seis modelos de programação, a saber: a) desnutrição protéica materna na lactação (dieta com 8 porcento de proteína); b) bloqueio da prolactina no fim da lactação, com o uso de bromocriptina; c) supernutrição na lactação por redução da ninhada (3 vs. 10 filhotes); d) injeção de leptina aos filhotes (8ug/100g peso corporal/dia, nos dez primeiros dias de lactação); e) exposição materna à nicotina (6 mg/kg de massa corporal/dia) na lactação; f) desnutrição protéica e calórica materna de ovelhas na lactação. Os ratos programados pela restrição protéica materna ganham menos massa corporal, menos gordura total e visceral, apresentam menor glicemia e insulinemia e a única alteração programada no perfil lipídico foi a menor concentração sérica de colesterol total (16 porcento). Os ratos cuja prolactina materna foi bloqueada ganharam mais massa corporal, maior gordura total e visceral, apresentaram maior índice de resistência à insulina e menor adiponectinemia, que se refletiu em um perfil lipídico bastante alterado, com elevação do colesterol total (30 porcento)...

Nutritional status on lactation is an important imprinting factor for future hormonal and metabolic changes during development, regulating body composition, glucose homeostasis and hormonal profile in animals, characterizing the programming effect. In this critical period of life, malnutrition or overnutrition changes the secretion and action of several hormones, such as prolactin, leptin and thyroid hormones. Although several epidemiologic studies confirm the programming effect upon the lipids profile in humans, caused by nutritional imprinting during gestation of lactation that can contribute to a higher risk of cardiovascular diseases, few experimental data was reported. Thus, our main objective was to study the lipid profile in several models of nutritional and hormonal imprinting in rats and ovine, related to the programming of body mass and composition and glucose homeostasis. We studied 6 models of programming: a) maternal protein malnutrition (8 percent protein); b) prolactin blockade at the end of lactation by bromocriptine c) early overnutrition on lactation by litter size reduction (3 vs. 10 pups); d) leptin injection to the pups (8 ug/100g body weight/day, for the first 10 days of lactation); e) maternal nicotine administration (6mg/Kg body mass/day) during lactation; f) ewes maternal protein (8 percent) or energie (60 percent) restriction during lactation. The programmed offspring whose mother were protein-restricted during lactation gain less body mass, and when they were 180 days-old, showed lower total and visceral fat mass, lower serum glucose and insulin and lower total cholesterol (-16 percent). The prolactin blockadge programmed for higher body mass, total and visceral fat mass, higher insulin resistance index and lower serum adiponectin, these effects were associated to several changes in the lipid profile, such as higher total cholesterol (30 percent), LDL-c (1,5X), VDLc (46 percent), triglycerides (49 percent) and lower HDLc...

Observations on the thermal selection of the pantanal caiman (Caiman crocodilus yacare) hatchlings (Crocodylia: Alligatoridae)

Three options of water temperatures in a thermal gradient that changed from 22 to 35 C were offered to Pantanal caiman (Caiman croocodilus yacare) hatchlings. Animals from two nests were submitted to temperatures during 19 days (Nest 1 - 20 caimans caught in the nature hours after hatching), corresponding to 1 to 7 observations periods, and 13 days (Nest 2 - 20 animals obtained by artificial incubation) relative to observation period 8. Caimans remain fasting during experimental period. Hatchlings were allocated in a enclosure containing three styrofoam boxes (120 L) disposed side by side enclosed by wire netting and filled with water to the top. Thus, the animals were free to access the boxes, which temperatures were changed at the end of each observation period to avoid position effects. Air temperature was keep close to 22 C by air conditioning and water temperature was controlled by thermostats. The trial was divided in three phases determined by elimination of the less frequented temperature and its substitution by another temperature. In a first phase of the experiment that contained 1, 2 and 3 observation periods, the thermostats were regulated to 22 C (BoxD), 26 C (BxC) and 32 C (BxA). In phase 2 to 26 C, 29.5 C (BxB) and 32 C, including 4, 5 and 6 periods. In the third phase that included 7 and 8 periods, the thermostats were adjusted to 29.5 C, 32 C and 35 C (BxE). The number of caimans in each box was recorded two to three times a day (8:00, 14:00 and 17:00h) before pointed water temperature. Mean water temperatures (+ standard deviation) and respective caiman frequency means by box/temperature were: Phase 1 (BxD/22.3 1.2 C - 10.3 percent; BxC/27.0 2.4 C - 32.0 percent and BxA/31.2 1.1 C - 57.6 percent); Phase 2 (BxC/26.6 2.8 C - 13.3 percent; BxB/29.3 2.2 C - 27.7 percent and BxA/31.3 1.2 C - 59.0 percent) and Phase 3 (BxB/29.5 3.6 C - 23.7 percent; BxA/31.0 2.2 C - 31.9 and BxE/34.0 2.2 C - 44.4 percent). Observing that in the phases 1 and 2 the box with hottest water (CxA) was more frequented. In the phase 3, the difference between higher and smaller frequency straiten to 20.7 percent, in relation to almost 46.5 percent in phases 1 and 2, indicating that water temperatures between 29.5 and 35 C resulted in body temperatures more next to the comfort zone, in the experimental conditions

Assessment of physiological stress in periparturient cows and neonatal calves.

Pregnancy is considered to be one of the physiological stressors. The stress hormone, cortisol is significantly involved in various events during periparturient period including initiation of parturition. The study was conducted to estimate the serum cortisol concentration in cows and the neonatal calves in order to correlate the effect of cortisol on certain haematological and biochemical parameters such as blood glucose level (BGL), total plasma protein (TPP), lymphocyte:neutrophil ratio and mitogen induced lymphocyte proliferative response. Blood samples were collected from six cows in four periods, namely., 3 days prior to parturition, on the day of parturition, and 7 days after parturition. Blood samples were also collected from neonatal calves in the period 0, 7 and 14 days of age. Calves above two months of age and non-pregnant dry cows were considered as the controls. The serum cortisol concentration in cows on the day of parturition was significantly higher (P < 0.01) than controls and the value in calves was also significantly higher (P < 0.01) at 0 day than their controls. On the day of parturition BGL level of the dam and calves were significantly higher (P < 0.01), whereas the proliferative response of lymphocytes to mitogen was significantly lower (P < 0.01) than controls. However TPP levels did not differ significantly. This confirmed that the dam at the time of parturition and neonatal calf before taking colostrum are under a high risk of infection because of the low profile of immune status. The lymphocyte:neutrophil ratio also justified the above suggestion.

Estudo do comportamento motor decorrente da ingestäo de leite, em fetos de ratos: revisäo de literatura / Study of the motor behavior decurrent of the ingestion of milk in rat fetuses: review of literature

Nesta revisäo, focou-se os comportamentos motores e respostas fisiológicas de animais neonatos, associados com a ingestäo ou infusäo de leite, estudados em experimentos expressivos. Os experimentos demonstraram que os comportamentos e respostas foram mediados por neurotransmissores liberados, simultaneamente, à estimulaçäo com leite. Os experimentos säo apresentados detalhadamente com o objetivo de fornecer ao leitor uma visäo clara do desenvolvimento atual dos processos experimentais dessa linha de pesquisa.

Effects of exposure conditions to footshocks early in life on spontaneous locomotor activity at maturity in rats

Both genetic and environmental factors are involved in establishing a behavior. An animal study was done to determine the characteristics of interaction between genetic (nature) and environmental (nurture) factors. Delivery of footshocks (0.8 mA x 60 times, at random) early in life was used as the environmental stimulus. As the footshock was delivered repeatedly, a rat showed helplessness behavior and the number of shocks necessary to elicit helplessness was measured to quantify the trait of an animal in coping with the aversive environmental stimulus. The nocturnal ambulatory activity at adulthood was measured as a behavioral expression of the nature-nurture interaction. Although the experience of footshocks early in life did not significantly alter average activity levels at adulthood, the activity was positively correlated with the number of shocks necessary to elicit helplessness (nature) while receiving footshocks (nurture) on postnatal day 14. Additionally, a second exposure to identical shock parameters on postnatal day 21 reversed the relationship. These results clearly showed that an interaction between nature and nurture during infancy leads to substantial behavioral alterations later in life, and suggest that the nature-dependent determination of an adult behavior can be modified in different directions by the conditions of an environmental experience early in life.

Pancreatic juice and duodenal fluid flow rate in cow calves from birth to early ruminant state.

The present investigation on pancreatic juice (PJ) and duodenal fluid (DF) was carried out in 10 crossbred (Jersey x Kankrej) male cow calves from birth to early ruminant state (15 week). The respective samples were measured in situ by cannulating the pancreatic duct and duodenal lumen, 30 minutes before feeding (BF) and 30 minutes after feeding (AF) both during morning (MH) and evening (EH). The results revealed significant increase in PJ and DF flow rate with age. Diurnal effect was nonsignificant except a significant increase recorded during EH on 4 d for PJ and 3 d for DF.

Nutritional status and spontaneous locomotor activity in the rat.

A considerable amount of energy may be saved by lowering the spontaneous locomotor activity when energy intakes are reduced. The results of the present study in rats undernourished for a period of 21 or 60 days and subsequently fed ad libitum diet did not show any differences in activity when compared to their respective control groups, either during the undernourished periods or well fed states. Although this would mean that the rats are not economising energy on activity, it is probable that these rats with lower body weights are contributing to energy saving mechanism by reducing the cost of activity per se since the cost of activity and body weight are directly related.

Altered maternal thyroid function: fetal and neonatal development of rat.

Influence of maternal thyroid status on fetal and neonatal development of rats has been studied. Maternal hypothyroidism resulted impaired reproduction and intrauterine growth retardation of offsprings as revealed by their reduced body weight, heart weight, body length and tail length. Offsprings born to hypothyroid mothers showed very high rate of mortality and none of them survived beyond eight days. Maternal hyperthyroidism did not cause any abnormality on reproduction. Hyperthyroid mothers showed increased rate in body weight gain during pregnancy which was associated with increased weight of body and heart of fetuses born to hyperthyroid mothers. Plasma thyroxine was not measurable in fetus from hypothyroid mothers till 21st day of gestation. The results of the present study showed that maternal thyroid status plays an important role in fetal and neonatal growth and development.