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1.
PLoS One ; 15(2): e0220221, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32040479

RESUMO

Consequences of heat stress during pregnancy can affect the normal development of the offspring. In the present experiment, 30 Murciano-Granadina dairy goats (41.8 ± 5.7 kg) were exposed to 2 thermal environments varying in temperature-humidity index (THI) from 12 days before mating to 45 days of gestation. The environmental conditions were: gestation under thermal-neutral (TN; THI = 71 ± 3); and gestation under heat stress (HS; THI = 85 ± 3) conditions. At 27 ± 4 days old, female kids exposed to in utero TN (IUTN; n = 16) or in utero HS (IUHS; n = 10) were subjected to 2 tests: arena test (AT) and novel object test (NOT), the latter was repeated at 3 months of age. Additionally, 8 months after birth, a subset of IUTH and IUHS growing goats (n = 8 each; 16.8 ± 3.4 kg BW) were exposed to 2 environmental conditions in 2 consecutive periods: a basal thermal-neutral period (THI = 72 ± 3) for 7 days, and a heat-stress period (THI = 87 ± 2) for 21 days. In both periods, feeding, resting, posture, and thermally-associated behaviors were recorded. The gestation length was shortened by 3 days in GHS goats. In the AT, IUHS kids showed a lower number of sniffs (P < 0.01) compared to IUTN. In the NOT, IUHS kids also tended to show a lower number of sniffs (P = 0.09). During heat exposure, IUTN and IUHS growing goats spent more time resting and exhibited more heat-stress related behaviors such as panting and drinking (P < 0.001); however, no differences were observed between both groups. In conclusion, heat stress during the first third of pregnancy shortened gestation length and influenced the exploratory behavior of the kids in the early life. However, behavior responses to heat stress during the adulthood were not affected by the in utero thermal treatment.


Assuntos
Transtornos de Estresse por Calor/complicações , Efeitos Tardios da Exposição Pré-Natal/etiologia , Animais , Animais Recém-Nascidos , Comportamento Animal , Ingestão de Líquidos , Comportamento Exploratório , Feminino , Cabras , Transtornos de Estresse por Calor/veterinária , Resposta ao Choque Térmico , Gravidez , Efeitos Tardios da Exposição Pré-Natal/veterinária
2.
J Dairy Sci ; 102(12): 10695-10710, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31521355

RESUMO

Impaired fertility during periods of heat stress is the culmination of numerous physiological responses to heat stress, ranging from reduced estrus expression and altered follicular function to early embryonic death. Furthermore, heat-stressed dairy cattle exhibit a unique metabolic status that likely contributes to the observed reduction in fertility. An understanding of this unique physiological response can be used as a basis for improving cow management strategies, thereby reducing the negative effects of heat stress on reproduction. Potential opportunities for improving the management of dairy cattle during heat stress vary greatly and include feed additives, targeted cooling, genetic selection, embryo transfer and, potentially, crossbreeding. Previous studies indicate that dietary interventions such as melatonin and chromium supplementation could alleviate some of the detrimental effects of heat stress on fertility, and that factors involved in the methionine cycle would likely do the same. These supplements, particularly chromium, may improve reproductive performance during heat stress by alleviating insulin-mediated damage to the follicle and its enclosed cumulus-oocyte complex. Beyond feed additives, some of the simplest, yet most effective strategies involve altering the timing of feeding and cooling to take advantage of comparatively low nighttime temperatures. Likewise, expansion of cooling systems to include breeding-age heifers and dry cows has significant benefits for dams and their offspring. More complicated but promising strategies involve the calculation of breeding values for thermotolerance, the identification of genomic markers for heat tolerance, and the development of bedding-based conductive cooling systems. Unfortunately, no single approach can completely rescue the fertility of lactating dairy cows during heat stress. That said, region-appropriate combinations of strategies can improve reproductive measures to reasonable levels.


Assuntos
Doenças dos Bovinos/fisiopatologia , Transtornos de Estresse por Calor/veterinária , Reprodução , Ração Animal , Animais , Bovinos , Doenças dos Bovinos/terapia , Suplementos Nutricionais , Feminino , Fertilidade , Transtornos de Estresse por Calor/terapia , Lactação , Reprodução/fisiologia
3.
J Anim Sci ; 97(10): 4085-4092, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31396618

RESUMO

This experiment compared physiological and productive responses in finishing beef cattle managed under heat stress conditions, and supplemented (SUPP) or not (CON) with an immunomodulatory feed ingredient (Omnigen-AF; Phibro Animal Health, Teaneck, NJ). Crossbred yearling cattle (¾ Bos taurus × » Bos indicus; 64 heifers and 64 steers) were ranked by initial body weight (BW) (440 ± 3 kg) and sex, and allocated to 1 of 16 unshaded drylot pens (8 heifers or steers/pen). Pens within sex were randomly assigned to receive SUPP or CON (n = 8/treatment). Cattle received a total-mixed ration (91% concentrate inclusion and 1.21 Mcal/kg of net energy for gain; dry matter [DM basis]) during the experiment (day 0 to 106). The immunomodulatory feed was offered as a top-dress to SUPP pens (56 g/d per animal; as-fed basis) beginning on day 7. Cattle BW were recorded on day 0, 14, 28, 42, 56, 70, 84, 98, and 106. Feed intake was evaluated from each pen by recording feed offer daily and refusals biweekly. Intravaginal temperature of heifers was recorded hourly from day 1 to 6, 29 to 41, and 85 to 97. Environmental temperature humidity index (THI) was also recorded hourly throughout the experiment, and averaged 79.8 ± 0.6. Concurrently with BW assessment, hair samples from the tail-switch were collected (3 animals/pen) for analysis of hair cortisol concentrations. Blood samples were collected on day 0, 28, 56, 84, and 106 from all animals for plasma extraction. Whole blood was collected on day 0, 56, and 106 (3 animals/pen) for analysis of heat shock protein (HSP) 70 and HSP72 mRNA expression. Cattle were slaughtered on day 107 at a commercial packing facility. Results obtained prior to day 7 served as independent covariate for each respective analysis. Heifers receiving SUPP had less (P ≤ 0.05) vaginal temperature from 1500 to 1900 h across sampling days (treatment × hour, P < 0.01; 39.05 vs. 39.19 °C, respectively; SEM = 0.04), when THI ranged from 85.3 to 90.1. Expression of HSP70 and HSP72 was less (P ≥ 0.03) for SUPP cattle on day 106 (22.6- vs. 51.5-fold effect for HSP70, SEM = 9.7, and 11.0- vs. 32.8-fold effect for HSP72; treatment × day, P ≤ 0.04). No treatment effects were detected (P ≥ 0.22) for performance, carcass traits, plasma concentrations of cortisol and haptoglobin, or hair cortisol concentrations. Results from this study suggest that SUPP ameliorated hyperthermia in finishing cattle exposed to heat stress conditions, but such benefit was not sufficient to improve productive responses.


Assuntos
Ração Animal , Regulação da Temperatura Corporal , Bovinos/fisiologia , Suplementos Nutricionais , Transtornos de Estresse por Calor/veterinária , Imunomodulação/fisiologia , Ração Animal/análise , Animais , Peso Corporal , Dieta/veterinária , Feminino , Haptoglobinas/análise , Transtornos de Estresse por Calor/prevenção & controle , Cavalos , Umidade , Hidrocortisona/sangue , Masculino , Distribuição Aleatória , Carne Vermelha/análise , Temperatura
4.
J Anim Sci ; 97(10): 4101-4113, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31410479

RESUMO

Feedlot performance is reduced by heat stress and improved by ß adrenergic agonists (ßAA). However, the physiological mechanisms underlying these outcomes are not well characterized, and anecdotal reports suggest that ßAA may confound the effects of heat stress on wellbeing. Thus, we sought to determine how heat stress and ßAA affect growth, metabolic efficiency, and health indicators in lambs on a feedlot diet. Wethers (38.6 ± 1.9 kg) were housed under thermoneutral (controls; n = 25) or heat stress (n = 24) conditions for 21 d. In a 2 × 3 factorial, their diets contained no supplement (unsupplemented), ractopamine (ß1AA), or zilpaterol (ß2AA). Blood was collected on days -3, 3, 9, and 21. On day 22, lambs were harvested and ex vivo skeletal muscle glucose oxidation was determined to gauge metabolic efficiency. Feet and organ tissue damage was assessed by veterinary pathologists. Heat stress reduced (P < 0.05) feed intake by 21%, final bodyweight (BW) by 2.6 kg, and flexor digitorum superficialis (FDS) muscle mass by 5%. ß2AA increased (P < 0.05) FDS mass/BW by 9% and average muscle fiber area by 13% compared with unsupplemented lambs. Blood lymphocytes and monocytes were greater (P < 0.05) in heat-stressed lambs, consistent with systemic inflammation. Plasma insulin was 22% greater (P < 0.05) and glucose/insulin was 16% less (P < 0.05) in heat-stressed lambs than controls. Blood plasma urea nitrogen was increased (P < 0.05) by heat stress on day 3 but reduced (P < 0.05) on days 9 and 21. Plasma lipase and lactate dehydrogenase were reduced (P < 0.05) by heat stress. Glucose oxidation was 17% less (P < 0.05) in muscle from heat-stressed lambs compared with controls and 15% greater (P < 0.05) for ß2AA-supplemented compared with unsupplemented lambs. Environment and supplement interacted (P < 0.05) for rectal temperature, which was increased (P < 0.05) by heat stress on all days but more so (P < 0.05) in ß2AA-supplemented lambs on days 4, 9, and 16. Heat stress increased (P < 0.05) the frequency of hoof wall overgrowth, but ßAA did not produce any pathologies. We conclude that reduced performance in heat-stressed lambs was mediated by reduced feed intake, muscle growth, and metabolic efficiency. ß2AA increased muscle growth and improved metabolic efficiency by increasing muscle glucose oxidation, but no such effects were observed with ractopamine. Finally, ßAA supplementation was not detrimental to health indicators in this study, nor did it worsen the effects of heat stress.


Assuntos
Agonistas Adrenérgicos beta/administração & dosagem , Transtornos de Estresse por Calor/veterinária , Hipertrofia/veterinária , Doenças Musculares/veterinária , Fenetilaminas/administração & dosagem , Doenças dos Ovinos/tratamento farmacológico , Compostos de Trimetilsilil/administração & dosagem , Ração Animal/análise , Animais , Nitrogênio da Ureia Sanguínea , Peso Corporal , Dieta/veterinária , Suplementos Nutricionais , Transtornos de Estresse por Calor/metabolismo , Resposta ao Choque Térmico/efeitos dos fármacos , Temperatura Alta , Umidade , Hipertrofia/tratamento farmacológico , Hipertrofia/fisiopatologia , Imuno-Histoquímica , Masculino , Doenças Musculares/tratamento farmacológico , Doenças Musculares/fisiopatologia , Cadeias Pesadas de Miosina/análise , Distribuição Aleatória , Ovinos , Doenças dos Ovinos/fisiopatologia , Carneiro Doméstico
5.
J Therm Biol ; 84: 164-175, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466750

RESUMO

This study was conducted to investigate the effects of dietary GABA supplementation on blood biochemical parameters, the overall growth performance, and the relative mRNA expression of some FI- regulating genes in broiler chickens. A total of 192, three-day old chicks of mixed sex from two commercial broiler strains (Ross 308 and Cobb 500) were distributed into 2 groups; a control group and GABA-supplemented group (100 mg/kg diet). When the chicks reached 21 days of age, each group of each strain was randomly subdivided into two subgroups: one was exposed to HS (33 ±â€¯2 °C for 5 h/day for 2 weeks), while the other remained at thermoneutral temperature (24 °C). GABA significantly improved bird growth performance under normal and HS conditions, by increasing body weight (BW), weight gain (WG), and FI and significantly reduced the elevated body temperature of birds under HS. GABA supplementation increased FI by reducing the mRNA expression levels of FI-inhibiting neuropeptides, such as POMC, leptin, Ghrelin, and CCK, during HS and by increasing the expression of FI-stimulating neuropeptides such as AgRP and NPY. Moreover, GABA significantly altered FAS and ACC gene expression, resulting in significant increases in abdominal fat content in birds reared normally. In contrast, GABA lowered fat content in Cobb birds and increased it in Ross birds under HS. Therefore, GABA (100 mg/kg diet) is a strong FI-stimulating neurotransmitter and its regulatory effects depend on broiler strain and housing temperature.


Assuntos
Galinhas/fisiologia , Suplementos Nutricionais , Ingestão de Alimentos/efeitos dos fármacos , Ácido gama-Aminobutírico/farmacologia , Animais , Dieta/veterinária , Feminino , Transtornos de Estresse por Calor/metabolismo , Transtornos de Estresse por Calor/veterinária , Hormônios/genética , Abrigo para Animais , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Doenças das Aves Domésticas/metabolismo , Temperatura
6.
J Therm Biol ; 84: 190-199, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466753

RESUMO

MicroRNAs (miRNAs) expressions are altered by maternal stresses and nutritional status. Our previous study has demonstrated that maternal manganese (Mn) addition could protect chick embryos against maternal heat stress via enhancing anti-apoptotic ability in embryonic hearts. The objective of this study was to investigate whether this protective effect could be achieved via miRNA mechanisms, and also be sustained in offspring broilers. A completely randomized design with a 2 (maternal normal and high temperatures: 21 and 32 °C) × 2 (maternal control basal diet and the basal diet + 120 mg Mn/kg) factorial arrangement of treatments was adopted. Totally 96 broiler breeder hens were allotted to 4 treatments with 6 replicates. Subsequently, 24 hatched chicks from each maternal treatment were divided into 6 replicates. Maternal supplemental 120 mg Mn/kg reduced the increased expressions of miR-1551 and miR-34c in hearts of offspring embryos but not broilers under maternal heat stress. B-cell CLL/lymphoma 2 (BCL2) and NF-κB-inducing kinase (NIK) genes related to anti-apoptotic ability were identified as direct targets for miR-1551 and miR-34c, respectively. Under maternal heat stress, maternal supplemental 120 mg Mn/kg activated target BCL2 expression and NIK-dependent NF-κB pathway via mediating miR-1551 and miR-34c expressions in hearts of offspring embryos rather than broilers.


Assuntos
Doenças das Aves , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Coração/efeitos dos fármacos , Transtornos de Estresse por Calor/veterinária , Manganês/farmacologia , Animais , Apoptose/efeitos dos fármacos , Proteínas Aviárias/genética , Embrião de Galinha , Galinhas , Feminino , Coração/embriologia , Masculino , MicroRNAs , NF-kappa B/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética
7.
J Therm Biol ; 84: 250-258, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466761

RESUMO

The objective of this study was to determine whether the addition of açai (Euterpe oleracea) oil in the diets of lactating sheep under heat stress exerted beneficial effects on health as well as milk production and quality. Eighteen multiparous Lacaune sheep (2 or 3 parities; 28-30 days of lactation; average milk production of 1.7 L/sheep/day) were stratified by parity and milk production and were assigned randomly to 1 of 2 treatments (9 sheep/treatment): diet supplemented with 2% of soybean oil (SOY) or 2% of açai oil (AÇAI) in the concentrate for 14 days. The amount of oil added in the diet was equivalent to 0.65% of the total diet (dry matter basis). Blood and milk samples were collected on days 1, 10 and 14. On day 14, the AÇAI group sheep had lower serum concentrations of leukocytes, neutrophils, and lymphocytes than did the SOY group sheep. On day 14, AÇAI group sheep had lower serum concentration of triglycerides and urea, milk concentration of fat and total solid and milk lipid peroxidation than did SOY group sheep. However, on day 14, AÇAI group sheep had higher serum concentrations of glucose and globulin, serum and milk antioxidant capacity against peroxyl radicals, milk production and productive efficiency than did SOY group sheep. The fatty acids profile in milk did not differ between groups. These data suggest that açai oil improved the antioxidant activity in serum and milk and improved milk production and quality in dairy sheep under heat stress.


Assuntos
Suplementos Nutricionais , Euterpe , Transtornos de Estresse por Calor/metabolismo , Lactação/efeitos dos fármacos , Óleos Vegetais/farmacologia , Doenças dos Ovinos/metabolismo , Animais , Contagem de Células Sanguíneas , Dieta/veterinária , Ácidos Graxos/análise , Feminino , Transtornos de Estresse por Calor/sangue , Transtornos de Estresse por Calor/veterinária , Peroxidação de Lipídeos , Leite/química , Ovinos , Doenças dos Ovinos/sangue
8.
J Therm Biol ; 84: 259-265, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466762

RESUMO

The objective was to investigate the effects of dietary curcumin and acetylsalicylic acid (ASA) on the performance and physiological responses of broiler chickens under chronic thermal stress. One hundred and sixty day-old male chicks (Ross 308) were divided equally into 4 groups (each contained 4 replicates). On the day 22 of age and thereafter, the first group (TN) was raised in a thermoneutral condition (23 ±â€¯1 °C), while the second group (HS) was subjected to 8 h of thermal stress (34 °C) and both groups fed the basal diet with no supplements. The third (CR) and fourth (AS) groups were subjected to the same thermal stress conditions and fed curcumin-supplemented diet (100 mg curcumin kg-1 diet) and ASA-supplemented diet (1 g ASA kg-1 diet), respectively. Dietary treatment had a significant effect on ADFI (P = 0.041), average daily gain (P = 0.013) and final body weight (P = 0.001). The curcumin-supplemented had higher values for these measures compared with other experimental groups (P < 0.05). Also, the dietary curcumin supplement significantly increased the carcass yield as compared to the HS group (P < 0.05). Compared with the HS group, the dietary curcumin and ASA supplements decreased the concentration of malondialdehyde in the breast muscles (P = 0.014). Both dietary supplements exhibited a marked ability to restore the serum TAC, Na and K in heat-stressed broiler chickens. The current study reported a remarkable ability of curcumin supplement to restore the concentrations of polyunsaturated fatty acids (PUFA) in the breast muscles of heat-stressed broilers, including α-linolinec acid and Docosahexaenoic acid (P = 0.009 and 0.001, respectively). It could be concluded that supplemental dietary curcumin or ASA enhanced growth performance and antioxidant biomarkers of heat-stressed broilers. Moreover, curcumin might be an effective dietary supplement to alleviate the adverse effect of chronic thermal stress on carcass yield and meat quality.


Assuntos
Curcumina/farmacologia , Suplementos Nutricionais , Transtornos de Estresse por Calor/metabolismo , Aminoácidos/metabolismo , Animais , Biomarcadores/metabolismo , Galinhas/sangue , Galinhas/metabolismo , Dieta , Ácidos Graxos/metabolismo , Transtornos de Estresse por Calor/sangue , Transtornos de Estresse por Calor/veterinária , Masculino , Malondialdeído/metabolismo , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Doenças das Aves Domésticas/sangue , Doenças das Aves Domésticas/metabolismo
9.
J Therm Biol ; 84: 375-383, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466777

RESUMO

Bile acids (BAs) are critical for cholesterol homeostasis and new roles in metabolism and endocrinology have been demonstrated recently. It remains unknown whether BA metabolism can be affected by heat stress (HS). The objective of this study was to describe the shifts in serum, hepatic and intestinal BA profiles induced by chronic HS. Twenty-seven Large White pigs weighing 40.8 ±â€¯2.7 kg were assigned to one of the three treatments: a control group (CON, 23 °C), a HS group (33 °C), or a pair-fed group (PF, 23 °C and fed the same amount as HS group) for 21 d. The concentrations of taurine-conjugated BAs (TUDCA and THDCA in serum and TCDCA, TUDCA, THDCA and THCA in liver) were decreased in HS and PF pigs. However, in HS pigs, a reduction in taurine-conjugated BAs (TCBA) correlated with decreased liver genes expression of BA synthesis, conjugation and uptake transport. BA regulated-genes (FXR, TGR5 and FGFR4) in HS pigs and TGR5, FGFR4 and KLß in PF pigs were down-regulated in liver. In ileum, total BAs and glycoursodeoxycholic acid concentrations were higher in HS pigs than other groups and PF group, respectively (P < 0.05). TCBA (P = 0.01) and tauroursodeoxycholic acid (P < 0.01) were decreased in PF group. BA transporters (OSTα and MRP3) were up-regulated in HS pigs compared with CON and PF pigs, respectively (P < 0.01). In cecum, ursodeoxycholic acid was higher in HS (P = 0.02) group than CON group. The expression of apical sodium-coupled bile acid transporter (P = 0.04) was lower in HS pigs than CON pigs, while OSTß (P < 0.01) was greater in HS group than PF group. These results suggest that chronic HS suppressed liver activity of synthesis and uptake of TCBA, at least in part, which was independent of reduced feed intake.


Assuntos
Ácidos e Sais Biliares/metabolismo , Transtornos de Estresse por Calor/metabolismo , Doenças dos Suínos/metabolismo , Suínos/metabolismo , Animais , Ácidos e Sais Biliares/sangue , Conteúdo Gastrointestinal/química , Conteúdo Gastrointestinal/microbiologia , Transtornos de Estresse por Calor/veterinária , Resposta ao Choque Térmico , Temperatura Alta , Fígado/metabolismo , Masculino
10.
J Therm Biol ; 84: 384-397, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466778

RESUMO

The liver performs a significant role in innate and adaptive immunity. Heat stress causes oxidative stress in liver tissues and reduces the immune responses of laying hens which can cause several diseases affecting poultry-production performance. Hepatic inflammation is a common trigger of liver disease, which is reflected by hepatic tissue damage leading to fibrogenesis and hepatocellular carcinoma. Dietary manipulation of curcumin has been proposed to ameliorate the immune status of chickens under heat stress. Thus, this study aimed to investigate the effect of curcumin supplementation on TLR4 mediated non-specific immune response in liver of laying hens under high-temperature conditions. Experimental groups contained two controls groups (high temperature and thermo-neutral control (HC and NC) fed basal diet) and three high-temperature curcumin treatments groups (HT100, HT200 and HT300). Laying hens in HC and HT groups exposed 6 h/day heat stress (32 ±â€¯1 °C). The results of present study showed that heat stress curcumin treatment group had reduced inflammatory responses (IL-6, IL-1ß, TNF-α) as compared to HC and NC group. Pathological lesions and DNA damage of immune tissues were decreased in heat stress curcumin supplementation as compared to HC and NC group. Furthermore, PCNA, TLR4 and its downstream gene expression as well as protein expression (TLR4, NF-κB and PCNA) were significantly down regulated in heat stress curcumin supplemented group as compared to HC and NC group. Therefore, it is concluded that heat stressed hens supplemented with dietary curcumin enhance the immunity of laying hens and combat stressful environmental conditions.


Assuntos
Curcumina/farmacologia , Suplementos Nutricionais , Transtornos de Estresse por Calor/imunologia , Fígado/efeitos dos fármacos , Doenças das Aves Domésticas/imunologia , Receptor 4 Toll-Like/imunologia , Animais , Galinhas , Citocinas/sangue , Citocinas/genética , Citocinas/imunologia , Dieta/veterinária , Feminino , Transtornos de Estresse por Calor/patologia , Transtornos de Estresse por Calor/veterinária , Temperatura Alta , Fígado/imunologia , Fígado/patologia , NF-kappa B/imunologia , Doenças das Aves Domésticas/patologia , Antígeno Nuclear de Célula em Proliferação/imunologia
11.
J Therm Biol ; 84: 414-425, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31466781

RESUMO

Heat stress causes significant economic losses in poultry production, especially in tropical and arid regions of the world. Several studies have investigated the effects of heat stress on the welfare and productivity of poultry. The harmful impacts of heat stress on different poultry types include decreased growth rates, appetites, feed utilization and laying and impaired meat and egg qualities. Recent studies have focused on the deleterious influences of heat stress on bird behaviour, welfare and reproduction. The primary strategies for mitigating heat stress in poultry farms have included feed supplements and management, but the results have not been consistent. This review article discusses the physiological effects of heat stress on poultry health and production and various management and nutritional approaches to cope with it.


Assuntos
Transtornos de Estresse por Calor/prevenção & controle , Transtornos de Estresse por Calor/veterinária , Doenças das Aves Domésticas/prevenção & controle , Criação de Animais Domésticos , Animais , Fazendas , Transtornos de Estresse por Calor/fisiopatologia , Aves Domésticas , Doenças das Aves Domésticas/fisiopatologia
12.
Res Vet Sci ; 126: 94-102, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31445399

RESUMO

Heat stress is well documented to have a negative influence on livestock productivity and these impacts may be exacerbated by climate change. Dairy cattle can be more vulnerable to the negative effects of heat stress as these adverse impacts may be more profound during pregnancy and lactation. New emerging diseases are usually linked to a positive relationship with climate change and the survival of microrganisms and/or their vectors. These diseases may exaggerate the immune suppression associated with the immune suppressive effect of heat stress that is mediated by the hypothalamic-pituitary-adrenal (HPA) and the sympathetic-adrenal-medullary (SAM) axes. It has been established that heat stress has a negative impact on the immune system via cell mediated and humoral immune responses. Heat stress activates the HPA axis and increases peripheral levels of glucocorticoids subsequently suppressing the synthesis and release of cytokines. Heat stress has been reported to induce increased blood cortisol concentrations which have been shown to inhibit the production of cytokines such as interleukin-4 (IL-4), IL-5, IL-6, IL-12, interferon γ (IFNγ), and tumor necrosis factor-α (TNF- α). The impact of heat stress on the immune responses of dairy cows could be mediated by developing appropriate amelioration strategies through nutritional interventions and cooling management. In addition, improving current animal selection methods and the development of climate resilient breeds may support the sustainability of livestock production systems into the future.


Assuntos
Doenças dos Bovinos/etiologia , Transtornos de Estresse por Calor/veterinária , Resposta ao Choque Térmico/fisiologia , Animais , Bovinos , Doenças dos Bovinos/imunologia , Citocinas/metabolismo , Transtornos de Estresse por Calor/etiologia , Transtornos de Estresse por Calor/imunologia , Resposta ao Choque Térmico/imunologia , Sistema Hipotálamo-Hipofisário , Sistema Hipófise-Suprarrenal/fisiologia
13.
J Dairy Sci ; 102(9): 8537-8545, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31255266

RESUMO

Heat stress is known to affect performance of dairy cows experiencing prolonged periods of high temperature and relative humidity. Less is known about its effects in cooler climates. The goals of the present study were to determine the prevalence of days susceptible to cause mild heat stress in dairy cows living in a humid continental climate and to investigate the relationship between the number of consecutive days of mild heat stress and milk, fat, protein, and lactose production. A 6-yr data set (2010-2015) containing 606,031 milk analysis records for 34,360 Holstein dairy cows at different parities was matched with the corresponding daily maximum temperature-humidity index. Exposure to heat stress conditions was divided into 5 categories corresponding to 0, 1 to 2, 3 to 4, 5 to 6, and 7 to 8 consecutive days before milk test date. On average, cows were exposed to heat stress conditions for 135.8 ± 5.9 d/yr in Southwest Quebec and 95.3 ± 10.2 d/yr in Eastern Quebec. Cows experiencing heat stress conditions produced on average less fat, protein, and energy-corrected milk and lower fat and protein concentrations. The decrease in milk fat reached 6% for category 7 to 8 exposure of cows in parity 3 or more. The association between exposure category and milk yield and lactose yield and concentration was weak. Heat stress lowered milk fat and protein production but had little effect on milk volume output. Further research is necessary to better understand the mechanism underlying the effects of sporadic low- to medium-intensity heat stress on dairy productivity.


Assuntos
Bovinos/fisiologia , Clima , Resposta ao Choque Térmico/fisiologia , Umidade , Lactação/fisiologia , Temperatura , Animais , Gorduras/análise , Feminino , Transtornos de Estresse por Calor/veterinária , Leite/química , Leite/metabolismo , Proteínas do Leite/análise , Gravidez , Quebeque , Fatores de Tempo
14.
Trop Anim Health Prod ; 51(8): 2287-2295, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31154615

RESUMO

We investigated the thermotolerance of the F1 progeny (Black Bedouin × Damascus crossbreed) to summer conditions alongside that of two pure breeds. Male goats (n = 7 per breed) were used to conduct a summertime 28-day trial along with hypohydration. The animals were fitted with miniscule thermologgers, intraperitoneally and subcutaneously, to measure core (Tc) and peripheral (Tp) body temperatures (BT), respectively. All goats were kept under shaded housing for a 7-day basal period before being switched to unshaded pens for the next 21 days. During the first 14 days, animals had free access to water. However, during the third 7-day period, access to water was time-restricted (4 h/day). Finally, it was restricted to 40% of the third week's average daily intake over the last 7 days. Exposure to the unshaded conditions resulted in pronounced heat stress in all animals, as reflected by 0.42 and 1.44 °C rises for Tc and Tp, respectively. The F1 goats displayed a clear heterothermic adaptive response, especially after the water restriction bouts' initiation. Interestingly, the F1 goats displayed higher ratios of renal relative medullary thickness (77.7, 73.3, and 72.6 ± 1.1%) along with higher circulating concentrations of antidiuretic hormone (44.6, 31.6, and 11.6 ± 3.7 ng/mL), respectively, which suggested an improved water metabolism.


Assuntos
Cabras/fisiologia , Resposta ao Choque Térmico , Rim/fisiologia , Estado de Hidratação do Organismo , Termotolerância , Animais , Temperatura Corporal , Cruzamento , Transtornos de Estresse por Calor/veterinária , Temperatura Alta , Hibridização Genética , Masculino , Estações do Ano
15.
J Sci Food Agric ; 99(13): 5631-5637, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31106428

RESUMO

BACKGROUND: Chronic heat stress can enhance fat synthesis and result in lipid accumulation in the liver of broilers. To investigate the effects and molecular mechanisms of dietary taurine supplementation on fat synthesis and lipid accumulation in the liver of chronic heat-stressed broilers, 144 28 day-old chickens (Arbor Acres) were randomly distributed to normal control (NC, 22 °C, basal diet), heat stress (HS, consistent 32 °C, basal diet), or heat stress plus taurine (HS + T, consistent 32 °C, basal diet +5.00 g kg-1 taurine) groups for a 14-day feeding trial. RESULTS: Compared with those of the HS group, dietary taurine supplementation significantly decreased the level of very-low-density lipoprotein and the activity of aspartate aminotransferase in plasma and the relative weight of liver in the HS + T group. In addition, dietary taurine supplementation also significantly decreased the levels of triglyceride, acyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), and suppressed the mRNA expression levels of liver X receptor α (LXRα), sterol response element-binding protein 1c, ACC and FAS in the liver of chronic heat-stressed broilers. Meanwhile, dietary taurine supplementation effectively alleviated lipid accumulation in the liver of broilers exposed to chronic heat stress. CONCLUSION: Chronic heat stress significantly increased fat synthesis and resulted in excess lipid deposition in the liver of broilers. Dietary taurine supplementation can effectively decrease fat synthesis by suppressing the LXRα pathway and alleviate lipid accumulation in the liver of chronic heat-stressed broilers. © 2019 Society of Chemical Industry.


Assuntos
Gorduras/metabolismo , Transtornos de Estresse por Calor/veterinária , Receptores X do Fígado/metabolismo , Fígado/efeitos dos fármacos , Doenças das Aves Domésticas/tratamento farmacológico , Taurina/administração & dosagem , Ração Animal/análise , Animais , Aspartato Aminotransferases/metabolismo , Galinhas , Suplementos Nutricionais/análise , Ácido Graxo Sintases/genética , Ácido Graxo Sintases/metabolismo , Feminino , Transtornos de Estresse por Calor/tratamento farmacológico , Transtornos de Estresse por Calor/genética , Transtornos de Estresse por Calor/metabolismo , Resposta ao Choque Térmico , Temperatura Alta , Lipoproteínas VLDL/metabolismo , Fígado/metabolismo , Receptores X do Fígado/genética , Masculino , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/metabolismo , Doenças das Aves Domésticas/fisiopatologia , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Triglicerídeos/metabolismo
16.
Fish Physiol Biochem ; 45(4): 1409-1417, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31144086

RESUMO

Temperature plays an important role on reproductive physiology of vertebrates including mammals, fish, and birds. It has varying effects on fish reproduction depending on the species; higher temperatures favor the spring-spawning species, while lower temperatures stimulate reproduction in autumn spawners. To evaluate the impact of high temperature on the reproductive physiology of minnow Puntius sophore, we carried out expression analysis of selected genes associated with gamete quality (hsp60, hsp70, hsp90, hsf1, vtg), pleuripotency (sox2, oct4, nanog), and sex determination (dmrt1) in gonads (ovary and testis) of P. sophore, heat stressed for different time periods (36 °C/7 days or 60 days) using real-time quantitative polymerase chain reaction (RT-qPCR). Expression of most of the hsp, vtg, and pleuripotency marker genes sox-2, oct-4, and nanog genes was downregulated in both ovary and testis of heat-stressed fish. The expression of dmrt-1 was upregulated in testis but downregulated in ovary of the heat-stressed fish which could be a male favoring effect of high temperature in P. sophore. This study suggests that the reproductive physiology and health of the nutrient dense P. sophore would be negatively affected by high temperature stress.


Assuntos
Cyprinidae/genética , Transtornos de Estresse por Calor/genética , Ovário/metabolismo , Testículo/metabolismo , Animais , Feminino , Proteínas de Peixes/genética , Expressão Gênica , Transtornos de Estresse por Calor/veterinária , Proteínas de Choque Térmico/genética , Masculino , Proteína Homeobox Nanog/genética , Fator 3 de Transcrição de Octâmero/genética , Fatores de Transcrição SOX/genética , Fatores de Transcrição/genética , Vitelogeninas/genética
17.
J Therm Biol ; 82: 157-163, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31128643

RESUMO

The aim of this study is to evaluate the effects of Moringa oleifera (MO) on the performance, antioxidative status, and immune related gene expression in broilers raised under normal or heat stress conditions. Broiler chickens were distributed into 4 groups and fed diets with dietary MO at 0% or 5% (MO0 or MO5) and raised under ambient temperature 22 ±â€¯1 °C (N) or 35±1 °C (HS). HS conditions negatively affected the weight gain and FCR, while feeding MO exhibited beneficial effects especially under HS conditions. Triglycerides, total cholesterol and low-density lipoprotein cholesterol (LDL) levels were significantly (P < 0.05) higher in chickens raised in HS conditions and fed the basal diet than those in normal condition and fed with or without MO, while MO decreased triglycerides and total cholesterol levels in normal and HS conditions. Blood high-density lipoprotein cholesterol (HDL) was significantly decreased in broilers raised in HS conditions and fed diets without MO, while MO increased HDL level. Blood glutathione peroxidase (GSH-Px) was significantly (P < 0.05) decreased in broilers raised in HS conditions and fed the basal diet without MO. mRNA expression of GSH-Px was significantly (P < 0.05) downregulated in broilers raised in HS conditions and fed diets without MO. Broilers under normal or HS conditions and fed the basal diet exhibited significantly (P < 0.05) downregulated mRNA expressions of superoxide dismutase (SOD) and catalase (CAT) compared to chickens under normal conditions and fed MO. Liver and muscle thiobarbituric acid reactive substance (TBARs) were significantly (P < 0.05) increased in broilers under HS conditions and fed diet without MO. The expressions of interleukins (IL2 and IL6) were significantly (P < 0.05) downregulated in broilers under normal or HS conditions and fed diets without MO. To sum up, HS conditions depressed the performance, antioxidative status, and immune related gene expression in broilers, while MO obviously alleviated these negative effects in broilers.


Assuntos
Ração Animal , Galinhas/fisiologia , Resposta ao Choque Térmico , Moringa oleifera , Ração Animal/análise , Animais , Galinhas/crescimento & desenvolvimento , Galinhas/imunologia , Transtornos de Estresse por Calor/imunologia , Transtornos de Estresse por Calor/veterinária , Imunidade , Peroxidação de Lipídeos , Moringa oleifera/química , Estresse Oxidativo
18.
J Therm Biol ; 82: 197-205, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31128648

RESUMO

The objective of this study was to evaluate the effects of grape residue flour (GRF) on antioxidant activities, biochemistry variables, components of the immune system and milk production and quality of Lacaune sheep in heat stress. Twenty-seven multiparous lactating sheep [50 ±â€¯1.8 days (d) milking] were stratified by initial body weight, age, date of lambing and milk production and assigned randomly to 1 of 3 treatments (9 sheep/treatment): no GRF supplementation (control group) or supplementation at 1% (10 g/kg GRF) or 2% (20 g/kg GRF) of GRF (bark and seed) in the concentrate (grains and minerals mixture). Each ewe received 0.8 kg/d of concentrate, 3.6 kg/d of corn silage, and 0.25 kg/d of Cynodon spp hay. Milk production along with blood and milk samples were collected on d 1, 10 and 15. The 2% GRF sheep had increased serum concentrations of superoxide dismutase and glutathione peroxidase activity on d 15 compared to control sheep. Over time (d 10 to 15), lipid peroxidation was reduced in 2% GRF sheep. Total serum antioxidant capacity was greater in 2% GRF sheep compared to control sheep on d 10 and 15. Superoxide dismutase and glutathione peroxidase activity in milk samples were greater in 2% GRF sheep compared to control sheep. Supplementation with GRF did not affect milk production but GRF sheep were more efficient compared to control sheep. Protein and lactose concentrations were similar between treatments, but total solids and fat concentrations were greater in 2% GRF sheep compared to control sheep on d 15. Somatic cell count was reduced in GRF sheep compared to control sheep. In summary, supplementation with 2% GRF in dairy sheep in heat stress resulted in antioxidant and anti-inflammatory responses, which improved milk quality and reduced somatic cell count and lipid peroxidation.


Assuntos
Ração Animal , Resposta ao Choque Térmico , Leite/metabolismo , Carneiro Doméstico/fisiologia , Vitis , Ração Animal/análise , Animais , Suplementos Nutricionais/análise , Feminino , Transtornos de Estresse por Calor/veterinária , Lactação , Estresse Oxidativo , Vitis/química
19.
J Therm Biol ; 82: 90-98, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31128664

RESUMO

Heat stress (HS) adversely influences dairy cattle welfare and productivity. This study aimed to investigate the effects of HS on production and physiological parameters of Holstein cows. Two experiments each lasted 6 weeks were conducted in four Tunisian farms, firstly during summer under HS (n = 80, THI = 77) and later during autumn under thermo-neutral (n = 80, THI = 54) conditions. Respiration rate (RR), skin temperature (ST), rectal temperature (RT) and milk yield were measured, and milk samples were collected on 2 days every week during each experimental period. Temperature and relative humidity were measured inside the barn to calculate the temperature-humidity index (THI). Mixed models were used to evaluate the effects of period and the relationships between THI and physiological and production traits. Reaction norm models were applied to quantify the individual responses of cows across the trajectory of THI during the HS period. A clustering methodology was developed to identify tolerant and sensitive cows to HS based on their slope for response of physiological and production traits during HS period. In summer, RR (61 breaths/min) and ST (37.7 °C) were 2.3- and 1.3-fold higher, whereas milk yield per milking was 24% lower compared with thermo-neutral conditions. Linear relationship between THI and RR, ST and RT was observed and showed increases by 2 breaths/min, 0.5 °C and 0.04 °C per increase in one THI unit, respectively. Inversely, milk, fat and protein yields showed a drop of 0.13 kg, 0.4 g and 0.3 g per milking per increase in one THI unit, respectively. Cows qualified to be heat tolerant by our work tended to have higher RR, ST, and RT and lower to almost no decay in milk yield compared to cows qualified to be heat sensitive. Specifically, RR could be used as a reliable indicator for thermotolerance. The results of this study deepen our understanding of different aspects of HS resilience.


Assuntos
Bovinos/fisiologia , Termotolerância , Animais , Feminino , Transtornos de Estresse por Calor/veterinária , Resposta ao Choque Térmico , Umidade , Lactação , Leite/metabolismo
20.
J Therm Biol ; 82: 99-106, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31128665

RESUMO

The temperature-humidity index (THI) has been extensively applied for assessing heat stress in moderate to hot conditions in dairy cattle. However, there exist wide variation between researchers in defining an appropriate range of THI values for denoting different levels of stress. The present study was aimed to reassess previously described heat stress indicators of dairy cattle of sub-tropical region of India. From comparative evaluation of meteorological data over previous four years (2014-2017) the period of year when high THI prevailed in the region was determined. Accordingly, the time period of sample collection and observation on animals was decided, so that a THI range of 68-86 could be covered. After analyzing physiological, biochemical parameters and expression profile of heat shock response (HSR) genes of animals in response to different THI, it was evident from the study that animal undergoes few or little changes at THI 72, but major physiological changes occurred after THI reached 74. At THI range 74-79, no drastic change in these parameters occurred suggesting animals undergo transient acclimatization in this range to maintain homeostasis. Once THI reached and crossed 80, this homeostasis was perturbed and animals experienced major physiological changes again. Overall, the study suggests that THI values indicating level of heat stress are dependent on the geographic location, as well as type of animal and therefore, existing THI should be recalibrated for different climatic region for accurate assessment of the heat stress.


Assuntos
Bovinos/fisiologia , Resposta ao Choque Térmico , Aclimatação , Animais , Bovinos/genética , Feminino , Transtornos de Estresse por Calor/veterinária , Temperatura Alta , Umidade , Hibridização Genética , Índia , Temperatura , Clima Tropical
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