Ellagic acid mitigates heat-induced testicular detriment in a mouse model.

Heat stress has been shown to have a detrimental impact on testicular activity and spermatogenesis. Ellagic acid is a plant-derived organic compound that has a variety of biological functions. Thus, it is believed that ellagic acid may improve heat-stressed testicular dysfunction. There has been no research on the impact of ellagic acid on heat-stressed testicular dysfunction. The mice were divided into 4 groups. The first group was the normal control group (CN), and the second received heat stress (HS) by submerging the lower body for 15 min in a water bath with a thermostatically controlled temperature kept at 43°C (HS), and the third and fourth groups were subjected to heat-stress similar to group two and given two different dosages of ellagic acid (5 mg/kg (EH5) and 50 mg/kg (EH50) for 14 days. Ellagic acid at a dose of 50 mg/kg improved the level of circulating testosterone (increased 3ßHSD) and decreases the oxidative stress. The testicular and epididymal architecture along with sperm parameters also showed improvement. Ellagic acid treatment significantly increases the germ cell proliferation (GCNA, BrdU staining) and Bcl2 expression and decreases active caspase 3 expression. Heat stress downregulated the expression of AR, ER-α and ER-ß, and treatment with ellagic acid increased the expression of ER-α and ER-ß markers in the 50 mg/kg treatment group. Thus, our finding suggests that ellagic acid ameliorates heat-induced testicular impairment through modulating testosterone synthesis, germ cell proliferation, and oxidative stress. These effects could be manifested by regulating androgen and estrogen receptors. However, the two doses showed differential effects of some parameters, which require further investigation.

Potential of exogenous melatonin administration to mitigate heat stress induce pathophysiology of chicken.

Melatonin (MT) is an amine hormone secreted by the body that has antioxidant and anti-inflammatory properties. The aim of this study was to investigate pathophysiological protection of MT in heat-stressed chickens. By modelling heat-stressed chickens and treating them with MT. After 21 days of administration, serum antioxidant enzymes, biochemical indices, inflammatory cytokine and heat-stress indices were detected, along with cardiopulmonary function indices and histological observations in chickens. The results show heat-stress induced a decrease (P < 0.05) in body weight and an increase in body temperature, which was reversed after MT intervention. Treatment with MT inhibited (P < 0.05) the secretion of pro-inflammatory factors interleukin-1ß, interleukin-6, tumor necrosis factor α, serum heat shock protein 70, corticosterone, and elevated (P < 0.05) the levels of biochemical factors total protein, albumin, globulin, and increased (P < 0.05) the activities of antioxidant enzymes superoxide dismutase, glutathione peroxidase and catalase in chicken serum caused by heat stress, and the best effect was observed with the medium dose of MT. The heat-stress caused cardiac atrophy and pulmonary congestion, decreased (P < 0.05) the cardiac function indices creatine kinase isoenzyme, cardiac troponin I, angiotensin receptor I, creatine kinase and lung function indices myeloperoxidase, angiotensin-II, heat shock factor I, and increased (P < 0.05) the lung vascular endothelial growth factor II. Sections of the heart and lungs after administration of MT were observed to be more complete with more normal tissue indices. At the same time, compared with heat stress, heart and lung function indices of grade chickens after MT administration were significantly (P < 0.05)reduced and tended to normal levels, and the best effect was observed in the medium-dose MT. In conclusion, heat stress can cause pathophysiological damage in chickens, and 1 mg/kg/d of exogenous melatonin can attenuate this adverse effect.

Effects of dietary curcumin nano-micelles on performance, biological responses, and thermal stress resilience in heat-stressed fattening lambs across varying temperature-humidity index conditions: Implications for climate change.

Heat stress poses a significant challenge to sheep farming in arid and semi-arid regions, impacting growth performance, health, and physiological responses. While sheep have innate mechanisms to manage heat stress, prolonged exposure impairs their performance and health. This study evaluated the influence of varying doses of Curcumin Nano-Micelle (CNM) on heat-stressed fattening lambs in northeastern Iran over three months, examining the relationship between CNM doses and growth performance, feeding behavior, physiological responses, immune function, and antioxidant status. Thirty-two crossbred male lambs were included in a completely randomized design with four treatments and eight replications. The experimental treatments were as follows: 1) CTRL: No dietary inclusion of CNM, (control group); 2) T20: Dietary inclusion of 20 mg of CNM per head per day; 3) T40: Dietary inclusion of 40 mg of CNM per head per day; and 4) T80: Dietary inclusion of 80 mg of CNM per head per day. The results revealed that dietary supplementation with 20 and 40 mg of CNM significantly improved live body weight, weight gain, average daily gain (ADG), and feed conversion ratio (FCR) compared to the control treatment. Regression analysis demonstrated quadratic models between growth performance parameters and the Temperature-Humidity Index (THI), indicating a correlation between CNM doses and the animals' responses to heat stress. Regarding eating behavior, CNM doses of 40 and 80 mg/day significantly reduced eating time while increasing ruminating time. Blood analysis indicated significant reductions in glucose levels across all treatments, with T40 significantly reducing both cholesterol and triglyceride (TG) levels. Additionally, CNM supplementation decreased serum malondialdehyde (MDA) levels and increased superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, indicating enhanced antioxidant status. Physiological responses were influenced by CNM, notably reducing rectal temperature (RT), skin temperature (ST), respiration rate (RR), while pulse rate (PR) increased across various time intervals, particularly in the T80 group. This study demonstrates that CNM supplementation can enhance performance, physiological responses, and antioxidant status in heat-stressed fattening lambs, highlighting its potential to mitigate heat stress effects in sheep farming.

Therapeutic effects of mitoquinol during an acute heat stress challenge in growing barrows.

Study objectives were to determine the effects of mitoquinol (MitoQ, a mitochondrial-targeted antioxidant) on biomarkers of metabolism and inflammation during acute heat stress (HS). Crossbred barrows [n = 32; 59.0 ±â€…5.6 kg body weight (BW)] were blocked by BW and randomly assigned to 1 of 4 environmental-therapeutic treatments: 1) thermoneutral (TN) control (n = 8; TNCon), 2) TN and MitoQ (n = 8; TNMitoQ), 3) HS control (n = 8; HSCon), or 4) HS and MitoQ (n = 8; HSMitoQ). Pigs were acclimated for 6 d to individual pens before study initiation. The trial consisted of two experimental periods (P). During P1 (2 d), pigs were fed ad libitum and housed in TN conditions (20.6 ±â€…0.8 °C). During P2 (24 h), HSCon and HSMitoQ pigs were exposed to continuous HS (35.2 ±â€…0.2 °C), while TNCon and TNMitoQ remained in TN conditions. MitoQ (40 mg/d) was orally administered twice daily (0700 and 1800 hours) during P1 and P2. Pigs exposed to HS had increased rectal temperature, skin temperature, and respiration rate (+1.5 °C, +6.8 °C, and +101 breaths per minute, respectively; P < 0.01) compared to their TN counterparts. Acute HS markedly decreased feed intake (FI; 67%; P < 0.01); however, FI tended to be increased in HSMitoQ relative to HSCon pigs (1.5 kg vs. 0.9 kg, respectively; P = 0.08). Heat-stressed pigs lost BW compared to their TN counterparts (-4.7 kg vs. +1.6 kg, respectively; P < 0.01); however, the reduction in BW was attenuated in HSMitoQ compared to HSCon pigs (-3.9 kg vs. -5.5 kg, respectively; P < 0.01). Total gastrointestinal tract weight (empty tissue and luminal contents) was decreased in HS pigs relative to their TN counterparts (6.2 kg vs. 8.6 kg, respectively; P < 0.01). Blood glucose increased in HSMitoQ relative to HSCon pigs (15%; P = 0.04). Circulating non-esterified fatty acids (NEFA) increased in HS compared to TN pigs (P < 0.01), although this difference was disproportionately influenced by elevated NEFA in HSCon relative to HSMitoQ pigs (251 µEq/L vs. 142 µEq/L; P < 0.01). Heat-stressed pigs had decreased circulating insulin relative to their TN counterparts (47%; P = 0.04); however, the insulin:FI ratio tended to increase in HS relative to TN pigs (P = 0.09). Overall, circulating leukocytes were similar across treatments (P > 0.10). Plasma C-reactive protein remained similar among treatments; however, haptoglobin increased in HS relative to TN pigs (48%; P = 0.03). In conclusion, acute HS exposure negatively altered animal performance, inflammation, and metabolism, which were partially ameliorated by MitoQ.

Heat stress (HS) compromises animal health and productivity, and this causes major economic losses in almost every livestock sector. The negative consequences of HS are thought to originate from intestinal barrier dysfunction and subsequent immune activation. The underlying causes of lost intestinal integrity during HS are likely multifactorial; however, intestinal ischemia, increased accumulation of reactive oxygen species, and the ensuing epithelial oxidative damage might be potential causes. Mitochondria-targeted antioxidants, such as mitoquinol (MitoQ), are probably more effective than traditional dietary antioxidants (i.e., selenium, vitamin E) at alleviating oxidative stress, as they localize and accumulate within the mitochondria, potentiating their antioxidant activity. Thus, the present study aimed to investigate MitoQ's role during a thermal event in growing pigs. Herein, HS increased all body temperature indices, decreased feed intake (FI), and induced substantial body weight (BW) loss. Interestingly, the reduction in FI and BW was less dramatic in pigs receiving MitoQ. Changes in circulating metabolism and the acute phase response were observed due to the HS challenge; however, contrary to our expectations, these changes were not offset by MitoQ administration. Although our results suggest a positive MitoQ effect on growth performance, future studies are needed to corroborate the replicability of this response during HS.

Astaxanthin supplementation ameliorates simulated heat stress by regulating physio-biochemical responses in Sirohi goats.

The present study was undertaken to assess the ameliorative effect of dietary supplementation of astaxanthin in Sirohi goats under simulated heat stress conditions. Eighteen healthy female Sirohi goats were divided equally into three groups (n = 6): Heat-Stressed Control (HSC), Treatment 1 (T1), and Treatment 2 (T2). During the experiment, goats in the T1 group were supplemented with astaxanthin at the rate of 25 mg/animal/day, while those in the T2 group received supplementation of 50 mg/animal/day. The experiment was conducted for 42 days: 14 days of acclimatization period, next 21 days animals were exposed to 42ºC for 6 h from 09:00 h to 15:00 h and 7 days of recovery period. On a daily basis, we recorded the physiological responses of goats and collected environmental data at the experimental site. Blood samples were collected 0 and 14th days of acclimatization, on 1st, 6th, 11th, 16th and 21st day of heat exposure and on the 7th day of the recovery period. The rectal temperature and respiration rates of the treatment groups were lower than those of the HSC group during the exposure period. Heat stress in the supplemented groups was associated with reduced levels of hepatic enzymes such as AST and ALT. Serum urea, creatinine and albumin levels were significantly (P < 0.05) different between control and treatment groups. It was thus concluded that dietary inclusion of antioxidant astaxanthin can ameliorate induced thermal load as evident from changes in physio-biochemical parameters in the Sirohi goats, that was more prominent at 50 mg/ animal/day than 25 mg/ animal/day.

Melatonin administration during the first half of pregnancy improves physiological response and reproductive performance of rabbits under heat stress conditions.

Context Melatonin may have a heat-stress-alleviating role during pregnancy. Aims To investigate the effects of melatonin administration during the first half of pregnancy on heat-tolerance capacity and pregnancy outputs of naturally heat-stressed rabbits. Methods Forty female rabbits were stratified equally into two experimental groups and daily received 1mg melatonin/kg body weight or not (control) for 15 consecutive days post-insemination. Heat tolerance indices, hormone profile, ovarian structures, and fetal loss were determined. Key results Treatment with melatonin significantly decreased respiration rate and rectal temperature, improved concentrations of nitric oxide, and tended to decrease malondialdehyde concentrations (P =0.064) compared to control. Melatonin treatment significantly increased concentrations of high-density lipoprotein, oestradiol, and progesterone compared to control. No significant differences in the numbers of visible ovarian follicles, corpora lutea, and total implantation sites on day 18 of pregnancy were observed between experimental groups. However, melatonin treatment significantly reduced the number of absorbed implantation sites and significantly improved amniotic fluid volume and conception rate compared to control. Conclusions Melatonin administration during the first half of pregnancy can improve reproductive performance of heat-stressed female rabbits. Implications Melatonin can improve fetal survivability via improving heat-tolerance capacity of does and steroidogenesis.

Genistein alleviates chronic heat stress-induced lipid metabolism disorder and mitochondrial energetic dysfunction by activating the GPR30-AMPK-PGC-1α signaling pathways in the livers of broiler chickens.

The objective of this study was to investigate the preventive effects and mechanisms of genistein (GEN) on production performance and metabolic disorders in broilers under chronic heat stress (HS). A total of 120 male 3-wk-old Ross broilers were randomly assigned to 5 groups: a thermoneutral zone (TN) group maintained at normal temperature (21°C ± 1°C daily), an HS group subjected to cyclic high temperature (32°C ± 1°C for 8 h daily), and 3 groups exposed to HS with varying doses of GEN (50, 100, or 150 mg/kg diet). The experimental period lasted for 3 wk. Here, HS led to a decline in growth performance parameters and hormone secretion disorders (P < 0.05), which were improved by 100 and 150 mg/kg GEN treatment (P < 0.05). Moreover, the HS-induced increases in the liver index (P < 0.01) and abdominal fat rate (P < 0.05) were attenuated by 150 mg/kg GEN (P < 0.05). The HS-induced excessive lipid accumulation in the liver and serum (P < 0.01) was ameliorated after 100 and 150 mg/kg GEN treatment (P < 0.05). Furthermore, the HS-induced decreases in lipolysis-related mRNA levels and increases in lipid synthesis-related mRNA levels in the liver (P < 0.01) were effectively blunted after 100 and 150 mg/kg GEN treatment (P < 0.05). Importantly, the HS-stimulated hepatic mitochondrial energetic dysfunction and decreases in the mRNA or protein levels of peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), nuclear respiratory factor 1, and mitochondrial transcription factor A in the liver were ameliorated by 150 mg/kg GEN (P < 0.05). Moreover, 50 to 150 mg/kg GEN treatment resulted in a significant increase in the mRNA or protein levels of G protein-coupled estrogen receptor (GPR30), AMP-activated protein kinase (AMPK) α1, phosphorylated AMPKα, and phosphorylated acetyl-CoA carboxylase α. Collectively, GEN alleviated metabolic disorders and hepatic mitochondrial energetic dysfunction under HS, possibly through the activation of GPR30-AMPM-PGC-1α pathways. These data provide a sufficient basis for GEN as an additive to alleviate HS in broilers.

Effect of lowering blood cortisol level along with progesterone priming on intensifying the secondary symptoms of oestrus in Murrah buffaloes during the hot summer months.

The present study sought to intensify oestrus symptoms in heat-stressed pre-pubertal Murrah buffalo heifers. The first experiment aimed at lowering the blood cortisol level. Twenty pre-pubertal buffalo heifers approximately 36-40 months of age were randomly allocated to four groups of five buffaloes. Group Gly received 100 ml glycerol orally for 8 days (day 0 is the start of treatments), group Gly-E received intra-muscular injections of 500 mg tocopherol (vitamin E activity) and 150 mg sodium selenite on alternate days (four treatments) in addition to treatments received by group Gly, group Gly-E + B-Ch received intra-muscular injections of vitamin B-complex and choline daily for 8 days in addition to the treatments received by group Gly-E. The control group Co-1 did not received any treatments. Blood cortisol and glucose level was measured on day 7 post-treatment. The second experiment sought to test the effect of lowering the blood cortisol level and progesterone priming on the intensity of oestrus symptoms in heat-stressed pre-pubertal buffalo heifers. Eighty buffaloes were allocated into four groups of twenty buffaloes. P4 group received intra-vaginal progesterone CIDR for 5 days (day 0 is the day of start of treatment). Gly-E group received the same treatment as in the first experiment for 7 days (day 0-6) and P4 + Gly-E received the combination of P4 and Gly-E groups. The control group Co-2 did not receive any treatments; however, on day 6, all groups received intra-muscular injection of 2 mg estradiol benzoate. The buffaloes were graded for oestrus symptoms on the basis of mucus discharge (A-scanty and B-copious), vulvar redness (slightly pink and moist-A and deep red and moist-B), ferning (nil or poor-A and good with arborization-B) and cellularity of cervical mucus (Type A goblet cells with round nucleus and abundant cytoplasm and Type B goblet cells with cylindrical nucleus and scanty cytoplasm). The blood glucose level (mean ± SEM) of Gly group on day 7 of treatment in experiment 1 was 58.3 ± 0.4 mg/dl that was significantly greater than Co-1 (52.4 ± 0.4 mg/dl), Gly-E (53.5 ± 0.8 mg/dl) and Gly-E + B-Ch (52.7 ± 0.6 mg/dl) groups; however, the difference was found to be non-significant among Co-1, Gly-E and Gly-E + B-Ch groups. The cortisol level (mean ± SEM) on day 7 in groups Gly (11.4 ± 0.6 ng/ml), Gly-E (8.1 ± 0.5 ng/ml) and Gly-E + B-Ch (7.5 ± 0.4 ng/ml) was significantly lower than groups Co-1 (15.5 ± 0.3 ng/ml), though the difference between groups Gly-E and Gly-E + B-Ch was non-significant and the level in group Gly-E significantly lower than Gly. Thus, the combination of vitamin E and selenium along with glycerol had the best effect in the reduction of blood cortisol level in heat-stressed buffaloes. In the second experiment the blood estradiol level on day 7 in all groups was around 40 pg/ml. Cortisol reduction (group Gly-E) improved oestrus symptoms (mucus discharge and ferning) compared to control, but when compared to group P4 showed non-significant difference with respect to mucus discharge, vulvar redness and ferning of cervical mucus. However, when cortisol reduction treatments were combined with progesterone priming (group P4 + Gly-E) oestrus symptoms were improved with respect to mucus discharge and ferning thus, combination treatment had synergistic effect. This effect was also observed with cellularity of cervical mucus, where combination treatment group P4 + Gly-E produced cervical mucus with significantly lower percentage of Type B cells compared to group P4 and group Gly-E. Thus, administration glycerol and vitamin E selenium combination reduces blood cortisol level and along with progesterone priming can be effective to improve the oestrus symptoms of buffaloes during the hot summer months.

Nano-selenium and Macleaya cordata Extracts Improved Immune Function and Reduced Oxidative Damage of Sows and IUGR Piglets After Heat Stress of Sows in Late Gestation.

To investigate the effects of nano-selenium (nano-Se) and Macleaya cordata extracts (MCE) on immune function and oxidative damage of sows and intrauterine growth retardation (IUGR) piglets exposed to heat stress (HS) in large-scale farms, a 2 × 2 factorial design was adopted in this test, and the two factors were nano-Se (0, 0.50 mg/kg) and MCE (0, 500 mg/kg). A total of 80 sows ([Landrace × Yorkshire] × Duroc, parity 2) were used in a 25-day trial from day 90 of gestation to delivery with 20 replications per group and 1 sow per replication. The dietary treatments of sows were as follows: (1) CON group, basic diet (0.30 mg/kg added Se, sodium selenite); (2) Nano-Se group, basic diet (0.00 mg/kg added Se) + 0.50 mg/kg added nano-Se; (3) MCE group, basic diet (0.00 mg/kg added Se) + 500 mg/kg added MCE; and (4) Combined group, basic diet (0.00 mg/kg added Se) + 0.50 mg/kg added nano-Se and 500 mg/kg added MCE. The activities of serum SOD, CAT, and GSH-Px of sows and IUGR piglets were significantly increased in MCE group and combined group, and the MDA content was extremely decreased. There were extreme differences in serum IgG level of sows and IUGR piglets, colostrum, and serum IgM level of IUGR piglets in MCE group and combined group compared with CON group. Maternal combined diets increased greatly the levels of serum IL-10 and IFN-γ of sows and IUGR piglets, and decreased extremely the contents of serum IL-1ß and TNF-α. MCE alone or combination with nano-Se in sow diets decreased greatly mRNA level of Hsp70 and increased mRNA level of Hsp27 in sows and IUGR piglets. In conclusion, nano-Se and/or MCE can be added to sow diets for the amelioration of HS-induced oxidative damage through improving immune function.

Immunohistochemical Expression of AQP2 and HSP70 in Broiler Kidney Tissue Treated with Salix tetrasperma Roxb. Extract under Heat Exposure.

The administration of plant extracts to broilers may be a way to mitigate the effects of heat stress. The importance of AQP2 and HSP70 compounds in maintaining the homeostasis of the chicken body when it is subjected to heat stress is well established. This study aims to determine the effect of giving the ethanolic extract of the leaves of Salix tetrasperma Roxb. on the immunohistochemical expression of AQP2 and HSP70 in exposed and unexposed broiler kidney tissue. This study used 36 samples of 28-day-old chicken kidneys. Chickens were kept in individual cages, provided with feed and drinking water ad libitum. The design used was a completely randomized design with 6 treatments and 6 replications: (a) chickens were reared in conditions exposed to heat (HS + 0); (b) chickens were reared in conditions exposed to heat and given Salix extract at a dose of 50 mg/L drinking water (HS + 50); (c) chickens were reared under heat-exposed conditions and given Salix extract at a dose of 100 mg/L drinking water (HS + 100); (d) chickens were reared in conditions without exposure to heat (n-HS + 0); (e) chickens were reared in conditions without exposure to heat and given Salix extract at a dose of 50 mg/L drinking water (nHS + 50); and (f) chickens were reared in conditions exposed without exposure to heat and given 100 mg/L drinking water (nHS + 100) of Salix extract. Salix extract was given for 24 hours and was renewed every 6 hours. The results showed that giving Salix extract 100 mg/L in drinking water to chickens exposed to heat (HS + 100) reduced the value of the H/L ratio. Giving Salix extract 50-100 mg/L in drinking water caused an upregulated AQP2 expression; on the other hand, it downregulated HSP-70 expression, in chicken kidney tubules both exposed to heat stress and nonexposed to heat stress. In conclusion, exposure to heat stress in broiler chickens and giving Salix extract can increase the formation of aquaporin 2 compounds and suppress the formation of HSP70.

Carbohydrate ingestion attenuates cognitive dysfunction following long-duration exercise in the heat in humans.

INTRODUCTION: To determine if electrolyte or carbohydrate supplementation vs. water would limit the magnitude of dehydration and decline in cognitive function in humans following long-duration hyperthermic-exercise. METHODS: 24 subjects performed 3 visits of 2 h walking (3mph/7% grade) in an environmental chamber (33 °C/10% relative humidity). In random order, subjects consumed water (W), electrolytes (Gatorade Zero; E), or electrolytes+carbohydrates (Gatorade; E+C). Throughout exercise (EX), subjects carried a 23 kg pack and drank ad-libitum. Pre-and post-EX, body mass (BM) and plasma osmolality (pOsm) were measured. Physiological Strain Index (PSI) and core temperature (TC) were recorded every 15 min. Plasma glucose (GLU) was measured every 30 min. Cognitive processing (SCWT) was measured post-EX and compared to baseline (BL). A subset of 8 subjects performed a normothermic (N) protocol (21 °C/ambient humidity) to ascertain how the exercise stimulus influenced hydration status and cognition without heat. RESULTS: There were no significant differences between fluid conditions (W, E, E+C) for BM loss (Δ2.5 ± 0.2, 2.5 ± 0.2, 2.3 ± 0.2 kg), fluid consumption (1.9 ± 0.2, 1.9 ± 0.2, 1.8 ± 0.2L), pOsm (Δ1.5 ± 2.7, 2.2 ± 2.4, 2.0 ± 1.5 mmol/L), peak-PSI (7.5 ± 0.4, 7.0 ± 0.6, 7.9 ± 0.5), and peak-TC (38.7 ± 0.1, 38.6 ± 0.2, 38.8 ± 0.2 °C). GLU decreased significantly in W and E, whereas it increased above BL in E+C at 60, 90, and 120 min (P < 0.05). Compared to BL values (43.6 ± 26 ms), SCWT performance significantly decreased in all conditions (463 ± 93, 422 ± 83, 140 ± 52 ms, P < 0.05). Importantly, compared to W and E, the impairment in SCWT was significantly attenuated in E+C (P < 0.05). As expected, when compared to the heat-stress protocol (W, E, E+C), N resulted in lower BM loss, fluid consumption, and peak-PSI (1.1 ± 0.1 kg, 1.2 ± 0.7L, 4.8, respectively), and improved SCWT performance. CONCLUSIONS: These data are the first to suggest that, independent of supplementation variety, cognitive processing significantly decreases immediately following long-duration exercise in the heat in healthy humans. Compared to water and fluids supplemented with only electrolytes, fluids supplemented with carbohydrates significantly blunts this decrease in cognitive function.

Ginger root powder enhanced the growth productivity, digestibility, and antioxidative capacity to cope with the impacts of heat stress in rabbits.

Heat stress is the most significant environmental factor involved in the impairment of the health status of rabbits and lowering their productivity. Using medicinal feed additives is suggested to relieve heat stress-induced oxidative stress in rabbits. The study investigated the possible protective role of ginger root (Zingiber officinale) against heat stress in rabbits. Five week old rabbits were assigned randomly into four groups (48 rabbits each) and fed a basal diet supplemented with 0, 2.5, 5.0, and 7.5 g ginger powder/kg diet. The temperature and relative humidity inside the rabbitry units were kept at 33.0 ± 5.5 °C and 74.5 ± 4.5%, respectively, during 8 weeks fattening period. The results showed that rabbits that received the 7.5 g ginger powder/kg supplement had the highest final body weight. Rabbits that received different ginger powder levels recorded lower mortality values during the experimental period compared to that received the control diet, but the differences were not significant (5.0 vs. 10.0%, respectively). Rabbits fed 5.0 and 7.5 g ginger diet recorded the best food conversion ratio (P < 0.001). The weight of the carcass was significantly increased (P < 0.01) by supplementing ginger powder in diets. The digestibility of dry matter, organic matter, crude protein, and nitrogen free extracts nutrients was increased, but ether extract was significantly decreased (P < 0.001) by using ginger powder in diets. The detected blood metabolites displayed increased total protein but decreased triglycerides, total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) in rabbits treated with ginger. Rabbits fed 5.0 and 7.5 g ginger powder had the highest plasma total antioxidative capacity (TAC) and the lowest (P < 0.01) plasma malondialdehyde (MDA) concentration compared to those fed control diet. Conclusively, supplementing ginger powder up to a 5.0 g/kg diet for growing rabbits is recommended to improve the growth performance and enhanced viability under heat stress conditions.

Rapamycin administration during an acute heat stress challenge in growing pigs.

Study objectives were to determine the effects of rapamycin (Rapa) on biomarkers of metabolism and inflammation during acute heat stress (HS) in growing pigs. Crossbred barrows (n = 32; 63.5 ± 7.2 kg body weight [BW]) were blocked by initial BW and randomly assigned to 1 of 4 environmental-therapeutic treatments: 1) thermoneutral (TN) control (n = 8; TNCon), 2) TN and Rapa (n = 8; TNRapa), 3) HS control (n = 8; HSCon), or 4) HS and Rapa (n = 8; HSRapa). Following 6 d of acclimation to individual pens, pigs were enrolled in two experimental periods (P). During P1 (10 d), pigs were fed ad libitum and housed in TN conditions (21.3 ± 0.2°C). During P2 (24 h), HSCon and HSRapa pigs were exposed to constant HS (35.5 ± 0.4°C), while TNCon and TNRapa pigs remained in TN conditions. Rapamycin (0.15 mg/kg BW) was orally administered twice daily (0700 and 1800 hours) during both P1 and P2. HS increased rectal temperature and respiration rate compared to TN treatments (1.3°C and 87 breaths/min, respectively; P < 0.01). Feed intake (FI) markedly decreased in HS relative to TN treatments (64%; P < 0.01). Additionally, pigs exposed to HS lost BW (4 kg; P < 0.01), while TN pigs gained BW (0.7 kg; P < 0.01). Despite marked changes in phenotypic parameters caused by HS, circulating glucose and blood urea nitrogen did not differ among treatments (P > 0.10). However, the insulin:FI increased in HS relative to TN treatments (P = 0.04). Plasma nonesterified fatty acids (NEFA) increased in HS relative to TN treatments; although this difference was driven by increased NEFA in HSCon compared to TN and HSRapa pigs (P < 0.01). Overall, circulating white blood cells, lymphocytes, and monocytes decreased in HS compared to TN pigs (19%, 23%, and 33%, respectively; P ≤ 0.05). However, circulating neutrophils were similar across treatments (P > 0.31). The neutrophil-to-lymphocyte ratio (NLR) was increased in HS relative to TN pigs (P = 0.02); however, a tendency for reduced NLR was observed in HSRapa compared to HSCon pigs (21%; P = 0.06). Plasma C-reactive protein tended to differ across treatments (P = 0.06) and was increased in HSRapa relative to HSCon pigs (46%; P = 0.03). Circulating haptoglobin was similar between groups. In summary, pigs exposed to HS had altered phenotypic, metabolic, and leukocyte responses; however, Rapa administration had limited impact on outcomes measured herein.

Effects of N-acetyl-l-cysteine on heat stress-induced oxidative stress and inflammation in the hypothalamus of hens.

The purpose of this study was to discuss the effects of N-acetyl-l-cysteine (NAC) on heat stress-induced oxidative stress and inflammation in the hypothalamus of hens in different periods. A total of 120 Hy-Line variety brown laying hens (12 weeks old) were randomly assigned to 4 groups with 6 replicates. The control group (C group) (22 ± 1 °C) received a basal diet, the NAC-treated group (N group) (22 ± 1 °C) received a basal diet with 1000 mg/kg NAC, and 2 heat-stressed groups (36 ± 1 °C for 10 h per day and 22 ± 1 °C for the remaining time) were fed a basal diet (HS group) or a basal diet with 1000 mg/kg NAC (HS + N group) for 21 consecutive days. The influence of NAC on histologic changes, oxidative stress and proinflammatory cytokine production was measured and analysed in hens with heat stress-induced hypothalamic changes. NAC effectively alleviated the hypothalamic morphological changes induced by heat stress. In addition, NAC attenuated the activity of the Nf-κB pathway activated by heat stress and decreased the expression of the proinflammatory cytokines IL-6, IL-18, TNF-α, IKK, and IFN-γ. In addition, NAC treatment regulated the expression of HO-1, GSH, SOD2 and PRDX3 by regulating the activity of Nrf2 at different time points to resist oxidative stress caused by heat exposure. In summary, dietary NAC may be an effective candidate for the treatment and prevention of heat stress-induced hypothalamus injury by preventing Nf-κB activation and controlling the Nrf2 pathway.

Stress and immunity in poultry: light management and nanotechnology as effective immune enhancers to fight stress.

The poultry industry plays a significant role in boosting the economy of several countries, particularly developing countries, and acts as a good, cheap, and affordable source of animal protein. A stress-free environment is the main target in poultry production. There are several stressors, such as cold stress, heat stress, high stocking density, and diseases that can affect birds and cause several deleterious changes. Stress reduces feed intake and growth, as well as impairs immune response and function, resulting in high disease susceptibility. These effects are correlated with higher corticosteroid levels that modulate several immune pathways such as cytokine-cytokine receptor interaction and Toll-like receptor signaling along with induction of excessive production of reactive oxygen species (ROS) and thus oxidative stress. Several approaches have been considered to boost bird immunity to overcome stress-associated effects. Of these, dietary supplementation of certain nutrients and management modifications, such as light management, are commonly considered. Dietary supplementations improve bird immunity by improving the development of lymphoid tissues and triggering beneficial immune modulators and responses. Since nano-minerals have higher bioavailability compared to inorganic or organic forms, they are highly recommended to be included in the bird's diet during stress. Additionally, light management is considered a cheap and safe approach to control stress. Changing light from continuous to intermittent and using monochromatic light instead of the normal light improve bird performance and health. Such changes in light management are associated with a reduction of ROS production and increased antioxidant production. In this review, we discuss the impact of stress on the immune system of birds and the transcriptome of oxidative stress and immune-related genes, in addition, how nano-minerals supplementations and light system modulate or mitigate stress-associated effects.

Dietary taurine supplementation ameliorates muscle loss in chronic heat stressed broilers via suppressing the perk signaling and reversing endoplasmic reticulum-stress-induced apoptosis.

BACKGROUND: Heat stress seriously affects animal health and induces enormous financial losses in poultry production. Exploring the appropriate means for ameliorating unfavorable effects caused by heat stress is essential. We investigated whether taurine supplementation could attenuate breast muscle loss in chronic heat-stressed broilers, as well as its mechanism. We designed three groups: a normal control group (22 °C), a heat stress group (32 °C) and a taurine treatment group (32 °C, basal diet + 5 g·kg-1 taurine). RESULTS: We found that taurine significantly moderated the decreases of breast muscle mass and yield, as well as the increases of serum aspartate aminotransferase activity and serum urine acid level in chronic heat-stressed broilers. Additionally, supplementary taurine significantly alleviated elevations of the cytoplasm Ca2+ concentration, protein expressions of GRP78 and p-PERK, mRNA expressions of Ca2+ channels (RyR1, IP3R3) and endoplasmic reticulum (ER) stress factors (GRP78, GRP94, PERK, EIF2α, ATF4, IRE1, XBP1, ATF6 and CHOP), apoptosis (Caspase-3 and TUNEL), protein catabolism, and the reduction of taurine transporter (TauT) mRNA expression in the breast muscle induced by chronic heat stress. CONCLUSION: Supplementary taurine could attenuate chronic heat stress-induced breast muscle loss via reversing ER stress-induced apoptosis and suppressing protein catabolism. © 2020 Society of Chemical Industry.

The effects of zinc amino acid complex on biomarkers of gut integrity, inflammation, and metabolism in heat-stressed ruminants.

Study objectives were to evaluate the effects of replacing 40 mg/kg of dietary Zn from Zn sulfate (ZS) with Zn amino acid complex (ZA; Zinpro Corporation, Eden Prairie, MN) on inflammation and intestinal integrity in heat-stressed and pair-fed (PF) ruminants. Forty Holstein steers (173.6 ± 4.9 kg) were randomly assigned to 1 of 5 dietary-environmental treatments: (1) thermoneutral (TN) ad libitum with 75 mg/kg of dry matter (DM) ZS (ZSCON); (2) TN pair-fed with 75 mg/kg DM ZS (ZSPF); (3) TN pair-fed with 40 mg/kg DM ZA and 35 mg/kg DM ZS (ZAPF); (4) heat stress (HS) ad libitum with 75 mg/kg DM ZS (ZSHS); and (5) HS ad libitum 40 mg/kg DM ZA and 35 mg/kg DM ZS (ZAHS). Before study initiation, calves were fed their respective diets for 21 d. Following the pre-feeding phase, steers were transferred into environmental chambers and were subjected to 2 successive experimental periods. During period 1 (5 d), all steers were fed their respective diets ad libitum and housed in TN conditions (20.2 ± 1.4°C, 30.4 ± 4.3% relative humidity). During period 2 (6 d), ZSHS and ZAHS steers were exposed to cyclical HS conditions (27.1 ± 1.5°C to 35.0 ± 2.9°C, 19.3 ± 3.5% relative humidity), whereas the ZSCON, ZSPF, and ZAPF steers remained in TN conditions and were fed ad libitum or pair-fed relative to their ZSHS and ZAHS counterparts. Overall, steers exposed to HS had markedly increased rectal temperature (0.83°C), respiration rate (26 breaths per min), and skin temperature (8.00°C) relative to TN treatments. Rectal temperature from ZAHS steers was decreased (0.24°C) on d 4 to 6 of HS relative to ZSHS steers. Regardless of diet, HS decreased DMI (18%) relative to ZSCON steers. Circulating glucose from HS and PF steers decreased (16%) relative to ZSCON steers. Heat stress and nutrient restriction increased circulating nonesterified fatty acids 2- and 3-fold, respectively, compared with ZSCON steers. Serum amyloid A increased ~2-fold in PF relative to ZSCON and HS steers. We detected no treatment effect on blood pH; however, ZAHS steers had increased HCO3 relative to ZSHS. Relative to ZSHS, ZAHS steers had increased jejunum villi height (25%), a tendency for increased ileum villi height (9%), and decreased duodenal villi width (16%). In summary, ZA supplementation has some beneficial effects on thermal indices, intestinal architecture characteristics, and biomarkers of leaky gut in heat-stressed steers, indicative of an ameliorated heat load, and thus may be a nutritional strategy to minimize negative consequences of HS.

Heatwaves, medications, and heat-related hospitalization in older Medicare beneficiaries with chronic conditions.

BACKGROUND: Heatwaves kill more people than floods, tornadoes, and earthquakes combined and disproportionally affect older persons and those with chronic conditions. Commonly used medications for chronic conditions, e.g., diuretics, antipsychotics disrupt thermoregulation or fluid/electrolyte balance and may sensitive patients to heat. However, the effect of heat-sensitizing medications and their interactions with heatwaves are not well-quantified. We evaluated effects of potentially heat-sensitizing medications in vulnerable older patients. METHODS: US Medicare data were linked at the zip code level to climate data with surface air temperatures for June-August of 2007-2012. Patients were Medicare beneficiaries aged ≥65 years with chronic conditions including diabetes, dementia, and cardiovascular, lung, or kidney disease. Exposures were potentially heat-sensitizing medications including diuretics, anticholinergics, antipsychotics, beta blockers, stimulants, and anti-hypertensives. A heatwave was defined as ≥2 days above the 95th percentile of historical zip code-specific surface air temperatures. We estimated associations of heat-sensitizing medications and heatwaves with heat-related hospitalization using self-controlled case series analysis. RESULTS: We identified 9,721 patients with at least one chronic condition and heat-related hospitalization; 42.1% of these patients experienced a heatwave. Heatwaves were associated with an increase in heat-related hospitalizations ranging from 21% (95% CI: 7% to 38%) to 33% (95% CI: 14% to 55%) across medication classes. Several drug classes were associated with moderately elevated risk of heat-related hospitalization in the absence of heatwaves, with rate ratios ranging from 1.16 (95% CI: 1.00 to 1.35) to 1.37 (95% CI: 1.14 to 1.66). We did not observe meaningful synergistic interactions between heatwaves and medications. CONCLUSIONS: Older patients with chronic conditions may be at heightened risk for heat-related hospitalization due to the use of heat-sensitizing medications throughout the summer months, even in the absence of heatwaves. Further studies are needed to confirm these findings and also to understand the effect of milder and shorter heat exposure.

Supplementation of Moringa oleifera leaf powder orally improved productive performance by enhancing the intestinal health in rabbits under chronic heat stress.

Heat stress jeopardizes animal's growth and health mainly through induction of oxidative stress and inflammation. The current study investigated the effects of Moringa oleifera leaf powder (MOLP) supplementation on productive performance and intestinal health of rabbits under chronic heat stress (HS). Young New Zealand White rabbits (male) at the age of 32 weeks (n = 21, mean body weight of 3318 ± 171 g) for four weeks' period were reared on commercial pelleted diet and divided into three groups: control (CON, 25 °C), HS (35 ± 1 °C) and HS (35 ± 1 °C) with MOLP (HSM) supplemented orally (200 mg/kg body weight). The results demonstrated that rabbits in the HSM group had reduced rectal temperature, respiration rate and improved FCR due to improved daily gain and better crude fiber (NDF) digestibility (P < 0.05) compared with HS group. MOLP improved intestinal integrity and function as indicated by lower serum diamine oxidase level and increased jejunal weight, length, villus height and ratio of villus height to crypt depth than heat-stressed rabbits. MOLP reversed the increased levels of serum cortisol, metabolic indicators i.e. glucose, insulin, and reduced concentrations of serum triiodothyronine. MOLP supplementation also significantly down-regulated the mRNA expression of tumor necrosis factor alpha (α), heat shock protein A2, glutathione peroxidase-1, interleukin (IL)-1α and increased the expression of IL-6. In conclusion, MOLP supplementation could enhance intestinal health along with production and metabolic indicators by alleviating the oxidative stress and inflammatory response in small intestine of hyper-thermic rabbits.

Transcriptomic and biochemical effects of pycnogenol in ameliorating heat stress-related oxidative alterations in rats.

BACKGROUND: Heat stress is a condition that is due to extreme heat exposure. It occurs when the body cannot keep its temperature healthy in response to a hot climate and associated with oxidative stress. Testicular hyperthermia can induce apoptosis of sperm cells, affect sperm production and decrease sperm concentration, leading to sperm disorder, for this reason, we examined the protective impact of pycnogenol that it has a wide range of biological benefits, including antioxidant, anti-inflammatory and anti-cancer activities against the oxidative alterations that happen in testicular and brain tissues due to heat stress in rats. STUDY DESIGN: Forty-eight Wistar male rats, approximately around 6 weeks age were allocated randomly into four groups (12 in each) of control, HS (subjected to heat stress and supplemented orally with 50 mg of pycnogenol/kg b. w./day dissolved in saline for 21 days), and pycnogenol (rats supplemented orally with 50 mg of pycnogenol/kg b. w./day dissolved in saline for 21 days). RESULTS: Data revealed a promising role of pycnogenol as an antioxidant, natural product to successfully reverse the heat-induced oxidative alterations in testicular and brain tissues of rats through significant upregulation of superoxide dismutase-2, catalase, reduced glutathione, and anti-apoptotic gene, while downregulating pro-apoptotic, and heat shock protein70. Pycnogenol treatment also reversed the reproductive hormone level and spermatogenesis to their normal values. CONCLUSION: Pycnogenol as a natural protective supplement could recover these heat stress-induced oxidative changes in testes and hypothalamus.