Thermal stress alters the basal value of serum proteins in laying hens / O estresse térmico altera o valor basal das proteínas séricas em galinhas poedeiras

This study aimed to evaluate the effect of thermal stress on the physiological and metabolic parameters in laying hens and the microbiological quality of eggs. The experiment was performed with 50 Rhode Island Red hens in the initial laying phase, under standard diet, lodged in 20 m² stalls under controlled temperature, for 30 days. The laying hens were randomly divided into two groups: G1 - the control group, which contained 10 hens exposed to the temperature of 17 ºC; G2 - the treatment group, which contained 40 hens exposed to the temperature of 30 ºC. The physiological parameters evaluated were: cloacal temperature, body surface temperature, heart rate, respiratory rate, and weight. Biochemical tests included total protein, albumin, globulin, and glucose. The group subjected to thermal stress showed lower body weight, increased heart rate, a slight increase in the respiratory rate, and increase in body surface temperature when compared with the control group (P < 0.05), although no significant differences were observed regarding cloacal temperature. As for the metabolic parameters, the treated group showed an increase in total proteins and globulins compared with the control group (P < 0.05), while albumin remained at basal levels. Additionally, hypoglycemia was observed in the treated group. Samples from egg shells and yolk were subjected to the analyses for the detection of Salmonella spp. These microorganisms were not detected amongst the egg samples.(AU)

O objetivo deste estudo foi avaliar o efeito do estresse térmico nos parâmetros fisiológicos e metabólicos de poedeiras, bem como na qualidade microbiológica dos ovos. O experimento foi realizado com 50 poedeiras da raça Rhode Island Red, em fase inicial de postura, recebendo dieta padronizada, alojadas em baias com aproximadamente 20 m2, com temperatura controlada, durante um período de 30 dias. As aves foram aleatoriamente divididas em dois grupos: G1 - grupo controle contendo 10 poedeiras expostas a uma temperatura de 17 °C; e G2 - grupo tratamento contendo 40 poedeiras expostas a uma temperatura de 30 °C. Os parâmetros fisiológicos avaliados foram: temperatura cloacal, temperatura corporal superficial, frequência cardíaca, frequência respiratória e peso. Foram realizados os exames bioquímicos de proteína total, albumina, globulina e glicose. No grupo mantido sob estresse térmico foi observado menor peso corporal, aumento na frequência cardíaca, leve aumento na frequência respiratória e aumento na temperatura corporal superficial quando comparado ao grupo controle (P < 0.05), enquanto que para temperatura cloacal não houve diferença entre os grupos. Com relação às avaliações metabólicas, foi observado um aumento nas proteínas totais e globulinas das aves do grupo tratado quando comparado ao grupo controle (P < 0.05), enquanto que a albumina se manteve a níveis basais. Adicionalmente, observou-se hipoglicemia no grupo tratado. Amostras da casca e gema dos ovos foram submetidas à análise de Salmonella spp.. O patógeno não foi detectado em nenhuma das amostras analisadas.(AU)

Thermal stress alters the basal value of serum proteins in laying hens / O estresse térmico altera o valor basal das proteínas séricas em galinhas poedeiras

This study aimed to evaluate the effect of thermal stress on the physiological and metabolic parameters in laying hens and the microbiological quality of eggs. The experiment was performed with 50 Rhode Island Red hens in the initial laying phase, under standard diet, lodged in 20 m² stalls under controlled temperature, for 30 days. The laying hens were randomly divided into two groups: G1 - the control group, which contained 10 hens exposed to the temperature of 17 ºC; G2 - the treatment group, which contained 40 hens exposed to the temperature of 30 ºC. The physiological parameters evaluated were: cloacal temperature, body surface temperature, heart rate, respiratory rate, and weight. Biochemical tests included total protein, albumin, globulin, and glucose. The group subjected to thermal stress showed lower body weight, increased heart rate, a slight increase in the respiratory rate, and increase in body surface temperature when compared with the control group (P < 0.05), although no significant differences were observed regarding cloacal temperature. As for the metabolic parameters, the treated group showed an increase in total proteins and globulins compared with the control group (P < 0.05), while albumin remained at basal levels. Additionally, hypoglycemia was observed in the treated group. Samples from egg shells and yolk were subjected to the analyses for the detection of Salmonella spp. These microorganisms were not detected amongst the egg samples.

O objetivo deste estudo foi avaliar o efeito do estresse térmico nos parâmetros fisiológicos e metabólicos de poedeiras, bem como na qualidade microbiológica dos ovos. O experimento foi realizado com 50 poedeiras da raça Rhode Island Red, em fase inicial de postura, recebendo dieta padronizada, alojadas em baias com aproximadamente 20 m2, com temperatura controlada, durante um período de 30 dias. As aves foram aleatoriamente divididas em dois grupos: G1 - grupo controle contendo 10 poedeiras expostas a uma temperatura de 17 °C; e G2 - grupo tratamento contendo 40 poedeiras expostas a uma temperatura de 30 °C. Os parâmetros fisiológicos avaliados foram: temperatura cloacal, temperatura corporal superficial, frequência cardíaca, frequência respiratória e peso. Foram realizados os exames bioquímicos de proteína total, albumina, globulina e glicose. No grupo mantido sob estresse térmico foi observado menor peso corporal, aumento na frequência cardíaca, leve aumento na frequência respiratória e aumento na temperatura corporal superficial quando comparado ao grupo controle (P < 0.05), enquanto que para temperatura cloacal não houve diferença entre os grupos. Com relação às avaliações metabólicas, foi observado um aumento nas proteínas totais e globulinas das aves do grupo tratado quando comparado ao grupo controle (P < 0.05), enquanto que a albumina se manteve a níveis basais. Adicionalmente, observou-se hipoglicemia no grupo tratado. Amostras da casca e gema dos ovos foram submetidas à análise de Salmonella spp.. O patógeno não foi detectado em nenhuma das amostras analisadas.

Influência da restrição alimentar e do estresse térmico sobre parâmetros fisiológicos em ovinos / [Influence of food restriction and heat stress on physiological parameters in sheep]

Objetivou-se avaliar as alterações fisiológicas de ovinos submetidos à restrição alimentar, expostos à radiação solar e à sombra. Dez borregas mestiças foram divididas igualmente em dois grupos: grupo radiação solar - GRS, animais expostos ao sol durante o dia; e grupo sombra - GS, animais alocados dentro de um galpão à sombra. Nos seis dias iniciais de experimento, os animais foram submetidos à restrição alimentar, com acesso apenas à água, já expostos ao sol ou à sombra. Nos seis dias subsequentes, foi ofertada dieta composta por ração e feno de alfafa (3%PV). Os parâmetros avaliados foram frequência respiratória (FR), temperatura retal (TR), ß-hidroxibutirato (BHB), pH urinário, ingestão de matéria seca (IMS) e dados bioclimáticos (temperatura, umidade relativa do ar e índice de temperatura e umidade - ITU). A FR foi o parâmetro em que houve maior diferença significativa entre os grupos (p<0,05). O balanço energético negativo foi constatado em todos os animais (BHB>0,8mmol/L; pH<7,0). Ovelhas que sofrem restrição alimentar durante períodos de alta temperatura e umidade têm menor frequência respiratória e temperatura interna, independentemente de estar na sombra ou pleno sol. Porém, quando normalizado a oferta de alimento as ovelhas em pleno sol têm menor ingestão de matéria seca.(AU)

We aimed to evaluate physiological changes in sheep submitted to food restriction, exposed to the sun or shade. Ten ewe lambs were equally divided into two groups: Sun Radiation Group - GRS, exposed to sun during day hours, and Shade Group - GS, with animals placed inside a barn. In the first six days of experiment, animals were submitted to food restriction, with access to fresh water, already exposed to sun and shade. In the following six days alfalfa hay and concentrate were provided to the animals (3%BW). Parameters assessed were respiratory rate (FR), rectal temperature (TR), ß-hydroxybutyrate, urinary pH, dry matter intake (IMS) and climate data (air temperature, humidity, and temperature-humidity index - ITU). The parameter that most differed between groups was FR. All animals presented negative energy balance (BHB>0.8mmol/L; pH<7,0). Ewe lambs submitted to food restriction during periods of high temperature and humidity have lower respiratory rate and intern temperature, independently of being exposed to sun or shade. However, when food was offered animals exposed to sun had lower dry matter intake.(AU)

Efeito das estações do ano e da idade sobre as variáveis termofisiológicas e hematológicas de bezerros leiteiros mestiços em ambiente tropical / Effect of season and age on thermophysiological and hematological variables of crossbred dairy calves in tropical environment

Background: The wellbeing and performance of calves may be impaired if raised in high temperature environments. Physiological and hematological variables serve as a tool to assess the welfare of cattle; therefore, the influence of seasons and age on physiological and hematological variables was evaluated of crossbred dairy calves in a tropical environment.Materials, Methods & Results: Forty-two male and female calves were evaluated from July 2016 to July 2017, when the calves were of 2, 15, 30, and 60 days of age. Respiratory (RR) and heart rates (HR) and rectal (RT) and body surface (BST) temperatures were quantified in the morning. Additionally, in the morning, dry bulb (Tdb) and wet bulb (Twb) temperatures were measured, and then, relative humidity (RH) and a temperature-humidity index (THI) were calculated. Blood was collected to perform hemogram. The day before the calves were evaluated, thermal environment data were collected to verify whether there were cyclic periods of heat stress. The mean air temperature ranged from 19°C to 22.1°C, and the highest THI value of 68 occurred in the summer mornings. In the afternoon, the maximum air temperature ranged from 27.5°C to 29.7°C. In autumn, respiratory and heart rates and body surface temperature were higher in 2-day-old calves than in other ages. The body surface temperature of 60-day-old calves was higher in spring and summer than in autumn. Rectal temperature remained in the normal range throughout the study period. Season did not influence the erythrogram and plaquetogram. The values for red blood cells, MCV, MCHC, RDW, platelets, and MPV varied among the calf ages. Season did not influence the values of leukocytes, monocytes, lymphocytes, or N/L ratio; however, band neutrophils and eosinophils varied among seasons. Band neutrophils and monocytes were not altered by age, whereas leukocyte, segmented neutrophils, eosinophils, lymphocytes, and N/L ratio values varied with age among the calves.[...]

Efeito das estações do ano e da idade sobre as variáveis termofisiológicas e hematológicas de bezerros leiteiros mestiços em ambiente tropical / Effect of season and age on thermophysiological and hematological variables of crossbred dairy calves in tropical environment

Background: The wellbeing and performance of calves may be impaired if raised in high temperature environments. Physiological and hematological variables serve as a tool to assess the welfare of cattle; therefore, the influence of seasons and age on physiological and hematological variables was evaluated of crossbred dairy calves in a tropical environment.Materials, Methods & Results: Forty-two male and female calves were evaluated from July 2016 to July 2017, when the calves were of 2, 15, 30, and 60 days of age. Respiratory (RR) and heart rates (HR) and rectal (RT) and body surface (BST) temperatures were quantified in the morning. Additionally, in the morning, dry bulb (Tdb) and wet bulb (Twb) temperatures were measured, and then, relative humidity (RH) and a temperature-humidity index (THI) were calculated. Blood was collected to perform hemogram. The day before the calves were evaluated, thermal environment data were collected to verify whether there were cyclic periods of heat stress. The mean air temperature ranged from 19°C to 22.1°C, and the highest THI value of 68 occurred in the summer mornings. In the afternoon, the maximum air temperature ranged from 27.5°C to 29.7°C. In autumn, respiratory and heart rates and body surface temperature were higher in 2-day-old calves than in other ages. The body surface temperature of 60-day-old calves was higher in spring and summer than in autumn. Rectal temperature remained in the normal range throughout the study period. Season did not influence the erythrogram and plaquetogram. The values for red blood cells, MCV, MCHC, RDW, platelets, and MPV varied among the calf ages. Season did not influence the values of leukocytes, monocytes, lymphocytes, or N/L ratio; however, band neutrophils and eosinophils varied among seasons. Band neutrophils and monocytes were not altered by age, whereas leukocyte, segmented neutrophils, eosinophils, lymphocytes, and N/L ratio values varied with age among the calves.[...](AU)

Resilient capacity of cattle to environmental challenges - An updated review

t Livestock rearing plays an integral role in enablingsmall and marginal farmers to ensure their livelihood security,which prevents both the food insecurity and poverty. Amongthe livestock, large ruminants and in particular cattle plays asignificant role from economic perspectives. This review is anattempt to compile information pertaining to thermo-toleranceof cattle to heat stress challenges. Heat stress has seriousconsequences, which negatively influence cattle productioncausing severe economic burden to the cattle farmers. Theability of the cattle to perform normal biological functions invarious adverse environmental conditions denotes its resilientcapacity. The resilience capacity is determined by varioustraits which govern maintaining their body conformation,respiratory and cutaneous evaporative cooling mechanisms,hair coat, maintenance of metabolic rate, feed efficiency,tolerance to dehydration, production maintenance andreproductive efficiency. Breed differences were establishedfor climate resilience and the superiority of indigenous breedsover exotic animals were established in this aspect. Theresilience capacity of indigenous cattle based on changesassociated with both phenotypic and genotypic traits werereviewed and several biological markers, which reflect theability of cattle to survive in different climatic conditions,were highlighted. The significance of refining the existingbreed program for imparting climate resilience was projectedto identify breeds, which have the ability to survive indifferent agro-ecological zones. (AU)

Resilient capacity of cattle to environmental challenges - An updated review

t Livestock rearing plays an integral role in enablingsmall and marginal farmers to ensure their livelihood security,which prevents both the food insecurity and poverty. Amongthe livestock, large ruminants and in particular cattle plays asignificant role from economic perspectives. This review is anattempt to compile information pertaining to thermo-toleranceof cattle to heat stress challenges. Heat stress has seriousconsequences, which negatively influence cattle productioncausing severe economic burden to the cattle farmers. Theability of the cattle to perform normal biological functions invarious adverse environmental conditions denotes its resilientcapacity. The resilience capacity is determined by varioustraits which govern maintaining their body conformation,respiratory and cutaneous evaporative cooling mechanisms,hair coat, maintenance of metabolic rate, feed efficiency,tolerance to dehydration, production maintenance andreproductive efficiency. Breed differences were establishedfor climate resilience and the superiority of indigenous breedsover exotic animals were established in this aspect. Theresilience capacity of indigenous cattle based on changesassociated with both phenotypic and genotypic traits werereviewed and several biological markers, which reflect theability of cattle to survive in different climatic conditions,were highlighted. The significance of refining the existingbreed program for imparting climate resilience was projectedto identify breeds, which have the ability to survive indifferent agro-ecological zones.

Simple physiological indicators of young goats bred in extensive system

The aim of this study was to evaluate the influence of day shift on physiological variables of young goats bred in an extensive system. Ten females of undefined racial pattern were used, with a mean age of 5 months, distributed in a completely randomized design, with two treatments (morning and afternoon shift) and 10 replications per treatment. The environmental variables were collected through a digital thermo-hygrometer. Respiratory and heart rate, and rectal temperature were measured. During the experimental period the averages of the air temperature and relative humidity, and the black globe-humidity index (BGHI) were of 38.80 ºC, 25.76% and 78.11, respectively. It was observed effect (P<0.05) of day shift on all physiological variables, with highest averages observed in the afternoon shift. The animals increased the respiratory and heart rate during the day periods to be able to maintain the rectal temperature within limits considered normal for this species.(AU)

Simple physiological indicators of young goats bred in extensive system

The aim of this study was to evaluate the influence of day shift on physiological variables of young goats bred in an extensive system. Ten females of undefined racial pattern were used, with a mean age of 5 months, distributed in a completely randomized design, with two treatments (morning and afternoon shift) and 10 replications per treatment. The environmental variables were collected through a digital thermo-hygrometer. Respiratory and heart rate, and rectal temperature were measured. During the experimental period the averages of the air temperature and relative humidity, and the black globe-humidity index (BGHI) were of 38.80 ºC, 25.76% and 78.11, respectively. It was observed effect (P<0.05) of day shift on all physiological variables, with highest averages observed in the afternoon shift. The animals increased the respiratory and heart rate during the day periods to be able to maintain the rectal temperature within limits considered normal for this species.

Productive and reproductive performance, behavior and physiology of cattle under heat stress conditions

This review aimed to detail the main information pertinent to the physiological and behavioral mechanisms evidenced in cattle under heat stress conditions. Brazilian cattle-breeding represents the second largest herd in the world, promoting great impact on the country's exports. Throughout their adaptability, these animals were submitted to different environments, which directly influence productive and reproductive performance, seeking compensatory mechanisms to maintain body homeostasis. Therefore, we can consider that heat stress directly affects the physiological and behavioral responses of cattle subjected to high temperatures. Adaptability of breeds to tropics should be considered of extreme importance in the choice of a productive activity for cattle-breeding and, particularly, in hot environments.(AU)

Productive and reproductive performance, behavior and physiology of cattle under heat stress conditions

This review aimed to detail the main information pertinent to the physiological and behavioral mechanisms evidenced in cattle under heat stress conditions. Brazilian cattle-breeding represents the second largest herd in the world, promoting great impact on the country's exports. Throughout their adaptability, these animals were submitted to different environments, which directly influence productive and reproductive performance, seeking compensatory mechanisms to maintain body homeostasis. Therefore, we can consider that heat stress directly affects the physiological and behavioral responses of cattle subjected to high temperatures. Adaptability of breeds to tropics should be considered of extreme importance in the choice of a productive activity for cattle-breeding and, particularly, in hot environments.

Effects of heat conditioning and dietary ascorbic acid supplementation on heat shock protein 70 expression, blood parameters and fear-related behavior in broilers subjected to heat stress

Background: Heat stress is one of the most important environmental factors. Exposure of broilers to high temperaturecauses signifi cant changes in physiological response. Early heat conditioning induces the heat tolerance of broiler chickensat later growth stage prior to marketing. Ascorbic acid supplementation has been reported to may alleviate the negative effects of heat stress on the performance of broilers. This study was carried out to investigate the effects of heat conditioningand dietary ascorbic acid supplementation on heat shock protein 70 expression, blood parameters and fear-related behaviorin broilers subjected to heat stress.Material, Methods & Results: A total of 320 male broilers were used as the material of this study. Broilers were randomlyassigned to four treatments. Each group contained four replicates with 20 chicks in each pen. Until the 21 days of age, allanimals were raised at comfort temperature. The brooding temperature was maintained at approximately 32oC for the fi rst3 days and then decreased 3oC weekly until 21 days. Broilers in control group were kept under thermo-neutral conditions(24oC) and fed with the basal diet throughout experimental period. Other three groups were exposed to heat stress from22 to 42 days of age. Heat stress was applied by exposing the broilers to a temperature of 35oC for 6 h/day between 10:00h and 16:00 h. Ascorbic acid supplemented group was fed a diet supplemented with 500 mg of L-ascorbic acid/kg rationand exposed to heat stress from 22 to 42 days of age. Heat conditioned group was exposed to a temperature of 36oC for 24h at the age of 5 days; fed with basal diet and exposed to heat stress from 22 to 42 days of age. Heat stress group was fedwith the basal diet, no subjected to heat conditioning and exposed to heat stress from 22 to 42 days of age. The broilers inheat stress group had higher body temperature, H/L, TI duration, serum corticosterone, glucose...

Effects of heat conditioning and dietary ascorbic acid supplementation on heat shock protein 70 expression, blood parameters and fear-related behavior in broilers subjected to heat stress

Background: Heat stress is one of the most important environmental factors. Exposure of broilers to high temperaturecauses signifi cant changes in physiological response. Early heat conditioning induces the heat tolerance of broiler chickensat later growth stage prior to marketing. Ascorbic acid supplementation has been reported to may alleviate the negative effects of heat stress on the performance of broilers. This study was carried out to investigate the effects of heat conditioningand dietary ascorbic acid supplementation on heat shock protein 70 expression, blood parameters and fear-related behaviorin broilers subjected to heat stress.Material, Methods & Results: A total of 320 male broilers were used as the material of this study. Broilers were randomlyassigned to four treatments. Each group contained four replicates with 20 chicks in each pen. Until the 21 days of age, allanimals were raised at comfort temperature. The brooding temperature was maintained at approximately 32oC for the fi rst3 days and then decreased 3oC weekly until 21 days. Broilers in control group were kept under thermo-neutral conditions(24oC) and fed with the basal diet throughout experimental period. Other three groups were exposed to heat stress from22 to 42 days of age. Heat stress was applied by exposing the broilers to a temperature of 35oC for 6 h/day between 10:00h and 16:00 h. Ascorbic acid supplemented group was fed a diet supplemented with 500 mg of L-ascorbic acid/kg rationand exposed to heat stress from 22 to 42 days of age. Heat conditioned group was exposed to a temperature of 36oC for 24h at the age of 5 days; fed with basal diet and exposed to heat stress from 22 to 42 days of age. Heat stress group was fedwith the basal diet, no subjected to heat conditioning and exposed to heat stress from 22 to 42 days of age. The broilers inheat stress group had higher body temperature, H/L, TI duration, serum corticosterone, glucose...(AU)

Effect of scrotal insulation on physical and morphological semen features in young cattle / Efeito da insulação scrotal sobre as características físicas e morfológicas do sêmen de touros jovens

The aim of this study was to evaluate the physical and morphological characteristics of semen from young cattle subjected to experimental testicular degeneration by scrotal insulation method. There were used three animals of the Holstein breed with an average of 12 months of age undergoing breeding soundness examination weekly for a period of 10 weeks. Semen was collected from animals by the method of electroejaculation and evaluated for physical characteristics of semen, sperm morphology and thermo-resistance test. Scrotal insulation for 120 hours increased scrotal temperature by 3.4 °C. The rectilinear progressive sperm motility and sperm vigor decreased between 7 to 28 days post-insulation (p<0.05) and sperm incidence with abnormal head increased between 21 to 35 days post-insulation. There was a decrease (p<0.05) in sperm motility during thermo-resistance test, for the periods post-insulation, indicating low sperm viability. The testicular degeneration induced by insulation bags may be temporary and even animals during puberty and adolescence have the ability for restructuring of the seminiferous epithelium and restoration of normal sperm production, although there is need for more recovery time.

O objetivo deste estudo foi avaliar as características físicas e morfológicas do sêmen de bovinos jovens submetidos à degeneração testicular experimental pelo método de insulação escrotal. Foram utilizados três animais da raça Holandesa, com uma média de 12 meses de idade, submetidos a exame andrológico semanalmente por um período de 10 semanas. O sêmen foi coletado pelo método de eletroejaculação e os animais avaliados quanto às características físicas e morfológicas do sêmen e teste de termorresistência. A insulação escrotal por 120 horas aumentou a temperatura escrotal em 3,4 °C. A motilidade espermática progressiva retilínea e vigor espermático diminuiram entre 7 a 28 dias pós-insulação (p<0,05) e a incidência de espermatozóides com a cabeça anormal aumentou entre 21 a 35 dias pós-insulação. Houve uma diminuição (p<0,05) na motilidade espermática durante o teste de termorresistência, nos períodos pós-insulação, indicando baixa viabilidade espermática. A degeneração testicular induzida por sacos de isolamento pode ser temporária e até mesmo animais durante a puberdade e adolescência têm a capacidade de reestruturação do epitélio seminífero e restauração da produção espermática normal, embora haja necessidade de maior tempo de recuperação.

Effect of pentoxifylline on the regeneration of rat testicular germ cells after heat shock

High temperature is an important factor for reproduction and can induce testicular degeneration. Pentoxifylline is a methylxanthine phosphodiesterase inhibitor with anti - inflammatory and anti - apoptotic properties. Considering the protective propert ies of pentoxifylline and the harmful effects of heat, the present study aimed to use pentoxifylline to reduce the damage induced by heat to the testis. Adult mal e Wistar rats were exposed to testicular heat shock (43ºC for 15 min) , treated with 50 or 100 mg/ k g of pentoxifylline and evaluated at 3, 7, 15, 30 and 60 days after heat shock. Pentoxifylline treatment did not change testicular weight, histomorphometrical parameters or plasma testosterone concentration. However, pentoxifylline inhibited germ cell apoptosis and reduced the severity of pathological lesions at 30 and 60 days after testicular heat shock. In conclusion, pentoxifylline treatment seem ed to inhibit pro - inflammatory and apoptotic mechanisms triggered by testicular heat shock, improving sper matogenesis regeneration.

Effect of scrotal insulation on physical and morphological semen features in young cattle / Efeito da insulação scrotal sobre as características físicas e morfológicas do sêmen de touros jovens

The aim of this study was to evaluate the physical and morphological characteristics of semen from young cattle subjected to experimental testicular degeneration by scrotal insulation method. There were used three animals of the Holstein breed with an average of 12 months of age undergoing breeding soundness examination weekly for a period of 10 weeks. Semen was collected from animals by the method of electroejaculation and evaluated for physical characteristics of semen, sperm morphology and thermo-resistance test. Scrotal insulation for 120 hours increased scrotal temperature by 3.4 °C. The rectilinear progressive sperm motility and sperm vigor decreased between 7 to 28 days post-insulation (p<0.05) and sperm incidence with abnormal head increased between 21 to 35 days post-insulation. There was a decrease (p<0.05) in sperm motility during thermo-resistance test, for the periods post-insulation, indicating low sperm viability. The testicular degeneration induced by insulation bags may be temporary and even animals during puberty and adolescence have the ability for restructuring of the seminiferous epithelium and restoration of normal sperm production, although there is need for more recovery time.(AU)

O objetivo deste estudo foi avaliar as características físicas e morfológicas do sêmen de bovinos jovens submetidos à degeneração testicular experimental pelo método de insulação escrotal. Foram utilizados três animais da raça Holandesa, com uma média de 12 meses de idade, submetidos a exame andrológico semanalmente por um período de 10 semanas. O sêmen foi coletado pelo método de eletroejaculação e os animais avaliados quanto às características físicas e morfológicas do sêmen e teste de termorresistência. A insulação escrotal por 120 horas aumentou a temperatura escrotal em 3,4 °C. A motilidade espermática progressiva retilínea e vigor espermático diminuiram entre 7 a 28 dias pós-insulação (p<0,05) e a incidência de espermatozóides com a cabeça anormal aumentou entre 21 a 35 dias pós-insulação. Houve uma diminuição (p<0,05) na motilidade espermática durante o teste de termorresistência, nos períodos pós-insulação, indicando baixa viabilidade espermática. A degeneração testicular induzida por sacos de isolamento pode ser temporária e até mesmo animais durante a puberdade e adolescência têm a capacidade de reestruturação do epitélio seminífero e restauração da produção espermática normal, embora haja necessidade de maior tempo de recuperação.(AU)

Effect of pentoxifylline on the regeneration of rat testicular germ cells after heat shock

High temperature is an important factor for reproduction and can induce testicular degeneration. Pentoxifylline is a methylxanthine phosphodiesterase inhibitor with anti - inflammatory and anti - apoptotic properties. Considering the protective propert ies of pentoxifylline and the harmful effects of heat, the present study aimed to use pentoxifylline to reduce the damage induced by heat to the testis. Adult mal e Wistar rats were exposed to testicular heat shock (43ºC for 15 min) , treated with 50 or 100 mg/ k g of pentoxifylline and evaluated at 3, 7, 15, 30 and 60 days after heat shock. Pentoxifylline treatment did not change testicular weight, histomorphometrical parameters or plasma testosterone concentration. However, pentoxifylline inhibited germ cell apoptosis and reduced the severity of pathological lesions at 30 and 60 days after testicular heat shock. In conclusion, pentoxifylline treatment seem ed to inhibit pro - inflammatory and apoptotic mechanisms triggered by testicular heat shock, improving sper matogenesis regeneration.(AU)

Respostas de suínos em terminação mantidos em diferentes ambientes térmicos / / Response of finishing swine maintained in different thermal environments

O objetivo, neste estudo, foi avaliar o comportamento, as respostas fisiológicas e o desempenho de suínos mantidos em diferentes ambientes térmicos. Foram utilizados 30 suínos machos castrados, distribuídos em delineamento inteiramente ao acaso, composto por dois tratamentos (ambiente de conforto térmico, 21°C e de estresse por calor, 32°C). Suínos mantidos sob estresse por calor permaneceram menos tempo na posição em pé, mais tempo na posição deitado, menos tempo em alimentação, fuçando e mais tempo dormindo. O tempo em que os animais permaneceram em ócio e bebendo não foi influenciado pelos ambientes. O ambiente de estresse por calor provocou redução do consumo de ração, do ganho de peso e piorou a conversão alimentar dos animais. Por outro lado, a eficiência de utilização da energia e da proteína para ganho de peso não foi influenciada pelos ambientes. Suínos submetidos ao ambiente de estresse por calor apresentaram carcaças mais leves, com maior rendimento e menor percentual de carne, o que resultou em menor índice de bonificação. Ambientes térmicos que provocam estresse por calor afetam negativamente o comportamento, as respostas fisiológicas, o desempenho e as características quantitativas da carcaça de suínos em terminação. (AU)

The objective in this study was to evaluate the behavior, physiological responses and the performance of the swine maintained in different thermal environments. Thirty barrows were used, distributed in a completely randomized design composed by two treatments (thermal comfort, 21°C and heat stress environment, 32°C). Pigs maintained under heat stress spent less time in the standing position, more time in the lying position, less time eating, rooting and more time sleeping. The period the animals remained in leisure and drinking was not affected by environment. The environment of heat stress caused a reduction of feed intake, weight gain and worsened feed: gain ratio. Moreover, the energy and protein utilization efficiency for weight gain was not affected by environments. Pigs submitted to environmental heat stress presented lighter carcasses, with higher values of carcass yield and lower percentage of meat, which resulted in lower bonus carcass index. Thermal environments which cause heat stress affect negatively behavior, physiological responses, performance and carcass quantitative characteristics of finishing swine. (AU)

Respostas de suínos em terminação mantidos em diferentes ambientes térmicos / / Response of finishing swine maintained in different thermal environments

O objetivo, neste estudo, foi avaliar o comportamento, as respostas fisiológicas e o desempenho de suínos mantidos em diferentes ambientes térmicos. Foram utilizados 30 suínos machos castrados, distribuídos em delineamento inteiramente ao acaso, composto por dois tratamentos (ambiente de conforto térmico, 21°C e de estresse por calor, 32°C). Suínos mantidos sob estresse por calor permaneceram menos tempo na posição em pé, mais tempo na posição deitado, menos tempo em alimentação, fuçando e mais tempo dormindo. O tempo em que os animais permaneceram em ócio e bebendo não foi influenciado pelos ambientes. O ambiente de estresse por calor provocou redução do consumo de ração, do ganho de peso e piorou a conversão alimentar dos animais. Por outro lado, a eficiência de utilização da energia e da proteína para ganho de peso não foi influenciada pelos ambientes. Suínos submetidos ao ambiente de estresse por calor apresentaram carcaças mais leves, com maior rendimento e menor percentual de carne, o que resultou em menor índice de bonificação. Ambientes térmicos que provocam estresse por calor afetam negativamente o comportamento, as respostas fisiológicas, o desempenho e as características quantitativas da carcaça de suínos em terminação.

The objective in this study was to evaluate the behavior, physiological responses and the performance of the swine maintained in different thermal environments. Thirty barrows were used, distributed in a completely randomized design composed by two treatments (thermal comfort, 21°C and heat stress environment, 32°C). Pigs maintained under heat stress spent less time in the standing position, more time in the lying position, less time eating, rooting and more time sleeping. The period the animals remained in leisure and drinking was not affected by environment. The environment of heat stress caused a reduction of feed intake, weight gain and worsened feed: gain ratio. Moreover, the energy and protein utilization efficiency for weight gain was not affected by environments. Pigs submitted to environmental heat stress presented lighter carcasses, with higher values of carcass yield and lower percentage of meat, which resulted in lower bonus carcass index. Thermal environments which cause heat stress affect negatively behavior, physiological responses, performance and carcass quantitative characteristics of finishing swine.

Taxa de sudação e parâmetros histológicos de bovinos submetidos ao estresse calórico / Sweat rate and histological parameters of cattle submitted to heat stress

Caracterizaram-se o pelame, a taxa de sudação e os parâmetros histológicos de 71 bovinos F2 (½ Gir x ½ Holandês), 39 machos e 32 fêmeas, entre 14 e 20 meses de idade, submetidos a condições de termoneutralidade (22ºC e 70 por cento de umidade relativa - UR) e ao estresse calórico (42ºC e 60 por cento UR). Os tratamentos foram realizados nas estações de verão e inverno em câmara bioclimática. O comprimento dos pelos e a espessura da capa foram maiores no inverno que no verão, sendo de 1,58 e 1,04cm e 5,31 e 3,91mm, respectivamente (P<0,05). A histologia da pele mostrou que, no verão, a área da glândula sudorípara e a distância da glândula ao epitélio foram menores que no inverno, sendo de 2589 e 4051µm e 294 e 344µm, respectivamente (P<0,05). Concluiu-se que a estação do ano influencia as características de pelame, o posicionamento e a atividade das glândulas sudoríparas de forma a maximizar o controle da homeostase térmica.(AU)

Coat thickness, sweat rate, and histological parameters were characterized in 39 males and 32 females crossbred cattle (½ Holstein x ½ Gir), averaging 14 to 20 months of age, submitted to thermoneutrality (22ºC and 70 percent of relative humidity - RH) and heat stress (42ºC and 60 percent RH) in summer and winter in a climatic chamber. Fur length and coat thickness were significantly higher in summer than winter, 1.58 and 1.04cm and 5.31 and 3.91mm, respectively (P<0.05). Skin histology showed that sweat gland area and distance of gland to epithelium was shorter in summer than in winter, 2,589 and 4,051µm and 294 and 344µm, respectively (P<0.05). It was concluded that the season influenced the coat thickness, the sweat glands disposal and activity to maximize thermic homeostasis control.(AU)