Functional oil in the feeding of heat-stressed Japanese quail.

The objective of the present study was to evaluate a blend of functional oils (FO) composed of copaiba and garlic essential oils, pepper oleoresin and cashew nut liquid to mitigate the effects of heat stress on productivity, egg quality, organ morphology of the gastrointestinal tract, serum biochemical profile, nutrient metabolism and body temperature of Japanese quail. A completely randomized design was used in a 3 × 2 factorial scheme (without additive; 300 and 500 mg FO/kg of feed x birds raised in a thermal comfort (TC) and heat stress (HS) environment), with 6 replicates of 8 birds per plot. The birds under HS had lower feed intake (P = 0.0000), egg mass (P = 0.0000), laying rate (P = 0.0000) and higher percentage of infertile non-commercial eggs (P = 0.0004), lower head temperature amplitude (P = 0.0000) and higher average of body temperature (P = 0.0312). HS worsened the external and internal quality of the eggs. Birds kept in HS showed higher values of cholesterol (P = 0.0000) and glutamic-pyruvic transaminase (P = 0.0272). The use of 300 and 500 g FO/ton of feed improved the feed conversion (P = 0.0000) and egg mass (P = 0.0000) of the quail bred under HS, respectively, by 8.4 and 7.2% and increased the relative weight of liver (P = 0.0064) and pancreas (P = 0.0492). The use of such additives also provided a higher % of yolk (P = 0.0018) and reduced the percentage of albumen (P = 0.0029) of the eggs produced in TC, in addition to reducing the amplitude of head temperature (P = 0.0484) of birds bred under HS. The breeding of Japanese quail under HS results in negative impacts on the production, physiological and qualitative aspects of the eggs. The use of 300 g/ton of FO in the diet of Japanese quail leads to improvements in feed conversion, increased liver capacity in nutritional metabolism and results in eggs with a higher proportion of yolks, being, therefore, an alternative for feeding quail in a hot climate.

Metabolic and productive parameters of lactating dairy cows under heat stress conditions supplemented with plant polyphenol extract.

The impact of heat stress on dairy cattle leads to significant economic losses and a negative impact on the welfare of the animals. The objective of this research was to evaluate the effect of the nutritional additive (Thermoplus®) in dairy cows under postpartum heat stress conditions, and its effects on the metabolic profile, production and quality of milk. Eighteen lactating Holstein cows (8 multiparous and ten primiparous), in a free-stall system, with a mean body condition score (BCS) of 3.14 ± 0.05, live weight of 624.55 ± 18, 61 kg, with initial mean days in milk (DIM) of 90 ± 10.11, were selected. The animals were grouped into a control (CG, n = 9) and a treatment (TG, n = 9). Both groups underwent 14 days of diet adaptation, the TG received the basal diet supplemented with 50 g of the additive, once a day, individually, while the control group received only the total diet. Data collection of metabolic and productive parameters were evaluated on days -14 (before adaptation), 1 (after the diet adaptation period), 16, 30, and 44. Milk, blood, and body condition score (BCS) were collected once a day, and heart rate, respiratory rate, and rectal temperature were collected twice a day. Serum concentrations of albumin, calcium, magnesium, glucose, gamma-glutamyl transferase (GGT), beta-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFAs), and paraoxonase-1 (PON-1) were evaluated. In the milk, the percentage of fat, protein, lactose, and total solids were determined in each sampling. Milk yield was measured daily. Humidity and ambient temperature values were collected on the days of the collection every 30 min, from 5:30 am to 5:00 pm, to calculate the temperature-humidity index (THI). Statistical analyzes were performed using the SAS software (version 9.3, SAS Institute Inc., Cary, NC, USA). The THI ranged from 62.22 to 79.47. Our findings showed that when the THI was greater than 72, the animals in the TG were able to maintain milk yield (Odds ratio (OD) = -0.0577,), and the animals in the CG had a greater chance of reducing it (OD = -0.2301). Multiparous cows in the TG had higher milk yield than CG (32.57 ± 0.34 vs 30.50 ± 0.36 kg per day; P = 0.0078) and lower SCC (34.110 ± 6,940 vs 665.50 ± 214.41 cells per ml; P = 0.03), with the same percentages of total solids (P > 0.05). In multiparous metabolic markers, TG when compared CG had higher albumin concentrations (2.50 ± 0.07 vs 2.12 ± 0.07 g/dl; < 0.001), equal PON-1 (P > 0.05), and higher BHBA levels (0.49 ± 0.03 vs 0.39 ± 0.04 mmol/l). Primiparous from the CG had higher concentrations of NEFA (0.18 ± 0.02 mmol/l) than multiparous from the same group (0.09 ± 0.02 mmol/l) P = 0.0265. The use of the plant polyphenol extract in postpartum Holstein cows challenged by heat stress had beneficial effects on the production and health of the mammary gland in multiparous cows without decreasing milk solids. The non-reduction of the activities of the acute phase proteins indicates an immunomodulatory and inflammatory-reducing effect of the product used.

HSP70 as a biomarker of the thin threshold between benefit and injury due to physical exercise when exposed to air pollution.

Physical exercise has acute and chronic effects on inflammatory balance, metabolic regulation, and redox status. Exercise-induced adaptations are mediated by enhanced 70-kDa heat shock protein (HSP70) levels and an improved heat shock response (HSR). Therefore, exercise could be useful against disease conditions [obesity, diabetes mellitus (DM), and exposure to atmospheric pollutants] marked by an impaired HSR. However, exercise performed by obese or diabetic subjects under pollution conditions might also be dangerous at certain intensities. Intensity correlates with an increase in HSP70 levels during physical exercise until a critical point at which the effort becomes harmful and impairs the HSR. Establishing a unique biomarker able to indicate the exercise intensity on metabolism and cellular fatigue is essential to ensure adequate and safe exercise recommendations for individuals with obesity or DM who require exercise to improve their metabolic status and live in polluted regions. In this review, we examined the available evidence supporting our hypothesis that HSP70 could serve as a biomarker for determining the optimal exercise intensity for subjects with obesity or diabetes when exposed to air pollution and establishing the fine threshold between anti-inflammatory and pro-inflammatory exercise effects.

Methionine supplementing effects on intestine, liver and uterus morphology, and on positivity and expression of Calbindin-D28k and TRPV6 epithelial calcium carriers in laying quail in thermoneutral conditions and under thermal stress.

This study aimed to provide the performance, localization and expression of the epithelial calcium transporter channels Calbindin-D28k (Calb) and TRPV6, and of the morphology of the digestive and reproductive system of laying quail under heat stress (HS), and with methionine supplementation (MS). This study characterized the positivity (immunohistochemistry) and expression (real-time PCR) of calcium channels in the kidneys, intestine and uterus of 504 laying quails under different MS (100, 110 and 120%) and temperatures (20, 24, 28 and 32°C). The animals under HS (32°C) had lower villus height, villus:crypt ratio, and goblet cell index in the duodenum and jejunum, fewer secondary and tertiary uterine folds, smaller hepatic steatosis, and increased number of distal convoluted renal tubules (CT) positive to Calb, and increased positivity in proximal CTs. Deleterious effects of HS were minimized with MS for: duodenal crypts, number of goblet cells of the jejunum, number of uterine folds, decreased Calb positivity in intestines and kidney, increased positivity of Calb in the uterus and increased TRPV6 gene expression in the kidney (P≤0.05). Epithelial calcium transporters were altered due to less need for calcium absorption and reabsorption due to more calcium available with the MS, increasing egg production in HS and quality in termoneutrality (P≤0.05). MS further increased intestinal villus absorption area and height, increased steatosis, decreased Calb positivity in the intestine and kidney, increased uterine positivity of Calb, and increase Calb and TRPV6 expression in the kidney (P≤0.001) under thermoneutrality. It was concluded that the use of MS (120%) is justifiable in order to partially reverse the deleterious effects of HS on the production, in the epithelial calcium carriers, and in the digestory and reproductive morphology of laying quail.

Upregulation of the clpB gene in response to heat shock and beta-lactam antibiotics in Acinetobacter baumannii.

The role of the clpB gene encoding HSP/chaperone ClpB was evaluated in the multiresistant antibiotic cells of Acinetobacter baumannii (RS4 strain) under stress-induced heat shock and different beta-lactams. The expression of the clpB gene was assessed by qPCR during heat shock at 45 °C and subinhibitory concentrations of ampicillin (30 µg mL-1), amoxicillin + sulbactam (8/12 µg mL-1), cefepime (30 µg mL-1), sulfamethoxazole + trimethoprim (120/8 µg mL-1) and meropenem (18 µg mL-1). The results indicated a transient increase in clpB transcription in all treatments except cefepime. Both in the presence of ampicillin and amoxicillin/sulbactam for 20 min, the mRNA-clpB synthesis was 1.4 times higher than that of the control at time zero. Surprisingly, the mRNA-clpB levels were more than 30-fold higher after 10 min of incubation with meropenem and more than eightfold higher in the presence of trimethoprim/sulfamethoxazole. In addition, western blot assays showed that the RS4 strain treated with meropenem showed a marked increase in ClpB protein expression. Our data indicate that during exposure to beta-lactams, A. baumannii adjusts the transcription levels of the clpB mRNA and protein to respond to stress, suggesting that the chaperone may act as a key cellular component in the presence of antibiotics in this bacterium.

A Role for Both V1a and V2 Receptors in Renal Heat Stress Injury Amplified by Rehydration with Fructose.

Chronic vasopressin secretion induced by recurrent mild heat stress exposure is significantly enhanced by limited rehydration with a fructose-containing beverage both in rodents and in humans. Moreover, this effect has been associated with upregulation of the polyol-fructokinase pathway and increased renal oxidative stress. Previously, we have shown that pharmacological inhibition of both V1a and V2 vasopressin receptors with conivaptan improved such renal alterations. The aim of this study was to evaluate the independent contributions of V1a and V2 receptors to the renal damage caused by mild heat stress and limited rehydration with a fructose-containing beverage. Osmotic minipumps were used to deliver either relcovaptan (0.64 mg/day) or tolvaptan (0.25 mg/day) in male Wistar rats for two weeks. Corresponding dilution vehicles were used as controls. To induce dehydration, rats were exposed to mild heat stress (37 °C for 1 h, Monday to Friday). All groups received a 10% fructose solution as a rehydration fluid for 2 h after mild heat stress. For the remainder of the day and on weekends, rats received tap water. The independent blockade of either the V1a or the V2 receptor prevented renal damage, reduced oxidative stress, and decreased plasma cortisol and systemic inflammation. However, the beneficial effects were regulated by different mechanisms. Tolvaptan inhibited polyol-fructokinase pathway overactivation, while relcovaptan prevented upregulation of the renin-angiotensin system and SGK1 expression. These data suggest that both V1a and V2 receptors participate in renal damage caused by heat stress-induced dehydration when fructose-containing beverages are used as rehydration fluids.

Addition of grape pomace flour in the diet on laying hens in heat stress: Impacts on health and performance as well as the fatty acid profile and total antioxidant capacity in the egg.

The aim of this study was to evaluate whether the addition of grape pomace flour (GPF) in the diet of laying hens at the end of the productive cycle and on heat stress could exert benefits on their health and performance, as well as egg quality. For this, 74-week-old laying hens (n = 64) were divided into four groups with four repetitions each, as follow: T0 (the control group; without GPF), T1 (1% GPF), T2 (2% GPF) and T3 (3% GPF) during 35 days. Percentage of laid eggs was higher in the group T1 compared to T0, and the feed intake was higher in the groups T1, T2 and T3 compared to T0. There was no difference regarding the chemical-physical composition of fresh eggs; however, eggs from GPF-fed chickens showed changes after storage regarding specific gravity, yolk index, pH of yolk, albumen and Haugh unit compared to T0. Fresh or stored egg yolk from GPF groups showed higher antioxidant capacity and lower lipid peroxidation compared to T0. GPF (3%) prevented the reduction of monounsaturated fatty acids in the yolk of stored eggs compared to T0. Glutathione peroxidase and superoxide dismutase activities, as well as total antioxidant capacity against peroxyl radicals were higher in the serum of laying hens that received GPF compared to T0, while lipid peroxidation was lower. In summary, the addition of GPF in the diet for laying hens at the end of the productive cycle can be beneficial for animal health and exerted positive effects in their performance and egg quality.

Thymol supplementation effects on adrenocortical, immune and biochemical variables recovery in Japanese quail after exposure to chronic heat stress.

Chronic heat stress (CHS) exposure negatively impairs avian' immunoneuroendocrine interplay. Thymol has shown several bioactive properties including antioxidant, bactericidal, antifungal and gamma-aminobutyric acid modulator activities. Indeed, supplementation with thymol has been used with positive effects on poultry production and immune-related variables. This study evaluates whether a thymol dietary supplementation can be used as a new functional feed strategy to mitigate CHS deleterious effects on endocrine, biochemical and immune-related variables. Starting at 100 days of age, 24 fully adult Japanese quail were fed with a diet supplemented with thymol (≈80 mg/quail per day) and other 24 quail remained non-supplemented (control diet). Between 119 and 127 days of age, half of the quail within those groups were submitted to a CHS by increasing environmental temperature from 24°C to 34°C during the light phase and the other half remained at 24°C (non-stressed controls). A period of 3 days after CHS ended (during the recovery period), corticosterone, albumin, total proteins and globulins and glucose concentrations, inflammatory response, antibody production and heterophil to lymphocyte (H/L) ratio were assessed. No differences between groups were found in basal corticosterone concentrations. Total proteins, total globulins and glucose concentrations were found elevated in the previously CHS group compared with their control counterparts. Regardless of the previous CHS exposure, thymol supplementation increased albumin concentrations and inflammatory responses and decreased antibody titers. An interaction between thymol supplementation and prior CHS exposure was found on the H/L ratio. Quail previously exposed to CHS and supplemented with thymol showed similar H/L values than their control non-stressed counterparts, suggesting that thymol has a stress preventive effect on this variable. The present findings together with the already reported thymol bioactive properties, suggest that feed supplementation with this compound could be a useful strategy to help overcoming some of the CHS induced alterations.

Characterization of Schinus lentiscifolius Marchand (Anacardiaceae) Bark Extract and Its Effects on Lymphocyte Oxidative Stress and Heat Shock Response.

Schinus lentiscifolius Marchand has been used in folk medicine to treat immunoinflammatory related diseases, which are marked by OS and altered HSR. Our study aimed to evaluate OS and HSR in lymphocytes treated with S. lentiscifolius bark extracts. S. lentiscifolius barks were partitioned with solvents to obtain hexane (SL-HEX), ethyl acetate (SL-ACOET) and methanol (SL-MEOH) extracts, and the presence of bioactive compounds was evaluated by thin layer chromatography. Total phenols were measured by the Folin-Ciocalteu method and flavonoids were identified by HPLC-DAD-ESI-MS/MS. Antioxidant capacity was verified by DPPH method, cell viability by Trypan Blue method, lipid peroxidation by TBARS and HSP70 by immunoblotting. The SL-ACOET extract presented higher content of phenolic compounds and antioxidant activity in vitro. It was able to reduce lipid peroxidation levels in lymphocytes induced by H2 O2 and improved cell viability. The SL-ACOET extract inhibited HSR by a decrease in both intracellular content and release of 70 kDa heat shock proteins (HSP70) and also by decrease extra-to-intracellular HSP70 ratio in lymphocytes submitted to heat shock (2 h, 41 °C). S. lentiscifolius bark extract has antioxidant activity and inhibitory effect on HSR probably due to the presence of polyphenols as the flavonoids quercetin and kaempferol.

Germination and initial development of Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae) seedlings under different temperatures and salinity levels / Germinação e desenvolvimento inicial de plântulas de Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae) em diferentes temperaturas e níveis de salinidade

Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae) is a species exclusive to the Caatinga biome. It is used as forage, firewood, and in the construction of fence posts. Species from this biome are constantly subjected to abiotic stresses, including salt and thermal stress. Thus, we evaluated the effect of irrigation water salinity on the germination and initial development of S. gardneriana seedlings at different temperatures. The experiment used seeds with an initial moisture content of about 12.32%, arranged in a factorial scheme with eight levels of salinity, obtained by the addition of sodium chloride (NaCl), diluted in distilled water at concentrations of 0.0 (control), 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 dS m-1, and the four temperatures 25, 30, 35, and 20-30°C, in four replicates of 25 seeds each. Salinity and temperature effects were evaluated based on germination, germination speed index, seedling shoot length, root length, shoot dry matter, root dry matter, and total dry matter. Increasing water salinity levels interfered with all variables analyzed in the germination of S. gardneriana seeds, especially at a temperature of 35°C. At temperatures of 25 and 30°C, seed germination and initial development were less affected by salinity. Simira gardneriana seeds are sensitive to salinity caused by the increase in NaCl from 1.5 dS m-1, which indicates a low tolerance of this species to saline environments. Our results show that the negative effect on the germination and initial development of S. gardneriana seedlings can be explained by the increase in salt levels and temperature, reducing their capacity to absorb water and nutrients, which indicates sensitivity responses of this species to salinity and thermal stress.

Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae), é uma espécie exclusiva do bioma Caatinga, utilizada como forrageira, e a madeira usada para lenha e estacas na construção de cercas. Espécies desse bioma são submetidas, constantemente, a estresses abióticos, entre eles o salino e o térmico. Dessa forma, objetivou-se avaliar o efeito da salinidade da água de irrigação na germinação e no desenvolvimento inicial de plântulas de S. gardneriana em diferentes temperaturas. Nesse estudo foram utilizadas sementes com teor de água inicial em torno de 12,32% às quais foram arranjadas em esquema fatorial com oito níveis de salinidades, obtidos a partir da adição de cloreto de sódio (NaCl) e diluídos em água destilada nas concentrações de 0,0 (testemunha); 1,5; 2,5; 3,5; 4,5; 5,5; 6,5 e 7,5 dS m-1 e quatro temperaturas de 25, 30, 35 e 20-30 °C, em quatro repetições de 25 sementes cada. Os efeitos da salinidade e da temperatura foram avaliados por meio da germinação, índice de velocidade de germinação, comprimento da parte aérea e da raiz, massa seca da parte aérea e da raiz e total de plântulas. O aumento dos níveis de salinidade da água interfere em todas as variáveis analisadas na germinação de sementes de S. gardneriana, principalmente sob a temperatura de 35 °C. Nas temperaturas de 25 e 30 °C a germinação e o desenvolvimento inicial das sementes são menos afetados pela salinidade. As sementes de S. gardneriana são sensíveis à salinidade causada pelo aumento do NaCl a partir de 1,5 dS m-1, o que indica baixa tolerância desta espécie em ambientes salinos. Os resultados obtidos neste trabalho mostram que o efeito negativo na germinação e desenvolvimento inicial de plântulas de S. gardneriana pode ser explicado pelo aumento dos níveis salinos e temperatura, reduzindo o poder da planta em absorver água e nutrientes, o que indica respostas de sensibilidade dessa espécie a salinidade e ao estresse térmico.

Germination and initial development of Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae) seedlings under different temperatures and salinity levels / Germinação e desenvolvimento inicial de plântulas de Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae) em diferentes temperaturas e níveis de salinidade

Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae) is a species exclusive to the Caatinga biome. It is used as forage, firewood, and in the construction of fence posts. Species from this biome are constantly subjected to abiotic stresses, including salt and thermal stress. Thus, we evaluated the effect of irrigation water salinity on the germination and initial development of S. gardneriana seedlings at different temperatures. The experiment used seeds with an initial moisture content of about 12.32%, arranged in a factorial scheme with eight levels of salinity, obtained by the addition of sodium chloride (NaCl), diluted in distilled water at concentrations of 0.0 (control), 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5 dS m-1, and the four temperatures 25, 30, 35, and 20-30°C, in four replicates of 25 seeds each. Salinity and temperature effects were evaluated based on germination, germination speed index, seedling shoot length, root length, shoot dry matter, root dry matter, and total dry matter. Increasing water salinity levels interfered with all variables analyzed in the germination of S. gardneriana seeds, especially at a temperature of 35°C. At temperatures of 25 and 30°C, seed germination and initial development were less affected by salinity. Simira gardneriana seeds are sensitive to salinity caused by the increase in NaCl from 1.5 dS m-1, which indicates a low tolerance of this species to saline environments. Our results show that the negative effect on the germination and initial development of S. gardneriana seedlings can be explained by the increase in salt levels and temperature, reducing their capacity to absorb water and nutrients, which indicates sensitivity responses of this species to salinity and thermal stress.(AU)

Simira gardneriana M.R. Barbosa & Peixoto (Rubiaceae), é uma espécie exclusiva do bioma Caatinga, utilizada como forrageira, e a madeira usada para lenha e estacas na construção de cercas. Espécies desse bioma são submetidas, constantemente, a estresses abióticos, entre eles o salino e o térmico. Dessa forma, objetivou-se avaliar o efeito da salinidade da água de irrigação na germinação e no desenvolvimento inicial de plântulas de S. gardneriana em diferentes temperaturas. Nesse estudo foram utilizadas sementes com teor de água inicial em torno de 12,32% às quais foram arranjadas em esquema fatorial com oito níveis de salinidades, obtidos a partir da adição de cloreto de sódio (NaCl) e diluídos em água destilada nas concentrações de 0,0 (testemunha); 1,5; 2,5; 3,5; 4,5; 5,5; 6,5 e 7,5 dS m-1 e quatro temperaturas de 25, 30, 35 e 20-30 °C, em quatro repetições de 25 sementes cada. Os efeitos da salinidade e da temperatura foram avaliados por meio da germinação, índice de velocidade de germinação, comprimento da parte aérea e da raiz, massa seca da parte aérea e da raiz e total de plântulas. O aumento dos níveis de salinidade da água interfere em todas as variáveis analisadas na germinação de sementes de S. gardneriana, principalmente sob a temperatura de 35 °C. Nas temperaturas de 25 e 30 °C a germinação e o desenvolvimento inicial das sementes são menos afetados pela salinidade. As sementes de S. gardneriana são sensíveis à salinidade causada pelo aumento do NaCl a partir de 1,5 dS m-1, o que indica baixa tolerância desta espécie em ambientes salinos. Os resultados obtidos neste trabalho mostram que o efeito negativo na germinação e desenvolvimento inicial de plântulas de S. gardneriana pode ser explicado pelo aumento dos níveis salinos e temperatura, reduzindo o poder da planta em absorver água e nutrientes, o que indica respostas de sensibilidade dessa espécie a salinidade e ao estresse térmico.(AU)

Astaxanthin counteracts the effects of heat shock on the maturation of bovine oocytes.

The cellular mechanisms induced by elevated temperature on oocytes are not fully understood. However, there is evidence that some of the deleterious effects of heat shock are mediated by a heat-induced increase in reactive oxygen species (ROS). In this context, carotenoid antioxidants might have a thermoprotective effect. Therefore, the objective of this study was to determine the role of astaxanthin (AST) on oocyte ROS production and on the redox profile and developmental competency of cumulus-oocyte complexes (COCs) after 14h heat shock (41°C) during in vitro maturation (IVM). Exposure of oocytes to heat shock during IVM increased ROS and reduced the ability of the oocyte to cleave and develop to the blastocyst stage. However, 12.5 and 25nM astaxanthin rescued these negative effects of heat shock; astaxanthin counteracted the heat shock-induced increase in ROS and restored oocyte developmental competency. There was no effect of astaxanthin on maturation medium lipid peroxidation or on glutathione peroxidase and catalase activity in oocytes and cumulus cells. However, astaxanthin stimulated superoxide dismutase (SOD) activity in heat-shocked cumulus cells. In conclusion, direct heat shock reduced oocyte competence, which was restored by astaxanthin, possibly through regulation of ROS and SOD activity in oocytes and COCs.

Inorganic salts and intracellular polyphosphate inclusions play a role in the thermotolerance of the immunobiotic Lactobacillus rhamnosus CRL 1505.

In this work, the thermotolerance of Lactobacillus rhamnosus CRL1505, an immunobiotic strain, was studied as a way to improve the tolerance of the strain to industrial processes involving heat stress. The strain displayed a high intrinsic thermotolerance (55°C, 20 min); however, after 5 min at 60°C in phosphate buffer a two log units decrease in cell viability was observed. Different heat shock media were tested to improve the cell survival. Best results were obtained in the mediumcontaining inorganic salts (KH2PO4, Na2HPO4, MnSO4, and MgSO4) likely as using 10% skim milk. Flow cytometry analysis evinced 25.0% live cells and a large number of injured cells (59.7%) in the inorganic salts medium after heat stress. The morphological changes caused by temperature were visualized by transmission electronic microscopy (TEM). In addition, TEM observations revealed the presence of polyphosphate (polyP) granules in the cells under no-stress conditions. A DAPI-based fluorescence technique, adjusted to Gram-positive bacteria for the first time, was used to determine intracellular polyP levels. Results obtained suggest that the high initial polyP content in L. rhamnosus CRL 1505 together with the presence of inorganic salts in the heat shock medium improve the tolerance of the cells to heat shock. To our knowledge, this is the first report giving evidence of the relationship between polyP and inorganic salts in thermotolerance of lactic acid bacteria.

Heat stress induces ferroptosis-like cell death in plants.

In plants, regulated cell death (RCD) plays critical roles during development and is essential for plant-specific responses to abiotic and biotic stresses. Ferroptosis is an iron-dependent, oxidative, nonapoptotic form of cell death recently described in animal cells. In animal cells, this process can be triggered by depletion of glutathione (GSH) and accumulation of lipid reactive oxygen species (ROS). We investigated whether a similar process could be relevant to cell death in plants. Remarkably, heat shock (HS)-induced RCD, but not reproductive or vascular development, was found to involve a ferroptosis-like cell death process. In root cells, HS triggered an iron-dependent cell death pathway that was characterized by depletion of GSH and ascorbic acid and accumulation of cytosolic and lipid ROS. These results suggest a physiological role for this lethal pathway in response to heat stress in Arabidopsis thaliana The similarity of ferroptosis in animal cells and ferroptosis-like death in plants suggests that oxidative, iron-dependent cell death programs may be evolutionarily ancient.

Role of insulin-like growth factor 1 on cross-bred Bos indicus cattle germinal vesicle oocytes exposed to heat shock.

Germinal vesicle (GV) oocytes are susceptible to heat stress. However, neither the cellular mechanisms triggered by elevated temperature nor the thermoprotective effects of insulin-like growth factor (IGF) on GV oocytes are completely understood. Therefore, a series of experiments was conducted to determine the direct effects of IGF1 (0, 12.5, 25, 50 and 100ng mL-1) on heat-treated GV oocytes. Butyrolactone-arrested GV oocytes were cultured at 38.5°C (control) or 41°C (heat shock; HS) for 14h in the presence of different concentrations of IGF1. Exposure of GV oocytes to 41°C increased (P<0.05) the number of terminal deoxyribonucleotidyl transferase-mediated fluorescein-dUTP nick end-labelling (TUNEL)-positive oocytes. At concentrations of 12.5 and 25ng mL-1, IGF1 tended to minimise these negative effect of HS (P=0.07). However, neither HS nor IGF1 had any effect on caspase activity. HS also decreased (P<0.05) GV oocyte mitochondrial activity and developmental competence to the blastocyst stage. These deleterious effects of HS were alleviated (P<0.05) by 12.5ng mL-1 IGF1. This concentration of IGF1 did not affect cleavage rate, the percentage of TUNEL-positive blastomeres and total blastocyst cell number regardless of temperature. In conclusion, exposure of GV oocytes to HS triggered the apoptotic cascade and compromised oocyte developmental competence. Physiological concentrations of IGF1 had a beneficial effect on heat-shocked GV oocytes.

Performance and carbon turnover in fast- and slow-growing broilers submitted to cyclic heat stress and fed on high-protein diets.

Two experiments were conducted to test the hypothesis that when using similar protein/amino acid diets and environment temperature conditions, the performance and carbon turnover in muscle and liver tissues, as measured by the incorporation of stable isotopes ((13)C/(12)C), must be different between fast-growing Cobb 500® and slow-growing Label Rouge broilers. For both experiments (Cobb and Label Rouge), 21-d-old birds were distributed in a completely randomised, 3 × 3 factorial design; three environmental temperatures (cyclic heat stress ad libitum, 22°C ad libitum, and 22°C restricted) and three crude protein concentrations (189.1, 210 and 220 g/kg CP) were used. The Cobb 500® had better performance with higher concentrations of crude protein. Cyclic heat stress (a temperature factor), negatively affected this genetic strain's performance. For the Label Rouge birds, the crude protein concentrations in the diet presented inconsistent results and cyclic heat stress did not affect the performance. The carbon turnover rate was affected in the Cobb 500® strain, with a high protein content reducing carbon turnover in the evaluated tissues (liver and muscles). Feed intake had a greater impact on carbon turnover rates than cyclic heat stress. The Label Rouge birds were not affected by the evaluated factors, suggesting that genetic improvement has a leading role on tissue carbon turnover. There is a genetic influence on carbon turnover in the liver and muscle tissues of broiler chickens. In addition, genetically fast-growing broilers are more susceptible to variations in diet composition and environmental temperature than less rapidly growing animals.

Consequences of experimental cortisol manipulations on the thermal biology of the checkered puffer (Sphoeroides testudineus) in laboratory and field environments.

Anthropogenic climate change is altering temperature regimes for coastal marine fishes. However, given that temperature changes will not occur in isolation of other stressors, it is necessary to explore the potential consequences of stress on the thermal tolerances and preferences of tropical marine fish in order to understand the thresholds for survival, and predict the associated coastal ecological consequences. In this study, we used exogenous cortisol injections to investigate the effects of a thermal challenge on checkered puffers (Sphoeroides testudineus) as a secondary stressor. There were no significant differences between control and cortisol-treated fish 48h following cortisol treatment for swimming ability (using a chase to exhaustion protocol), blood glucose concentrations or standard metabolic rate. In the lab, control and cortisol-treated puffers were exposed to ambient (29.1±1.5°C), ambient +5°C (heat shock) and ambient -5°C (cold shock) for 4h and to evaluate the consequences of abrupt temperature change on puff performance and blood physiology. Following cold shock, control fish exhibited increases in cortisol levels and weak 'puff' performance. Conversely, fish dosed with cortisol exhibited consistently high cortisol levels independent of thermal treatment, although there was a trend for an attenuated cortisol response in the cortisol-treated fish to the cold shock treatment. A 20-day complementary field study conducted in the puffer's natural habitat, a tidal creek in Eleuthera, The Bahamas, revealed that cortisol-injected fish selected significantly cooler temperatures, measured using accumulated thermal units, when compared to controls. These results, and particularly the discrepancies between consequences documented in the laboratory and the ecological trends observed in the field, highlight the need to establish the link between laboratory and field data to successfully develop management policies and conservation initiatives with regards to anthropogenic climate change.

The effect of astaxanthin on resistance of juvenile prawns Macrobrachium nipponense (Decapoda: Palaemonidae) to physical and chemical stress / Efecto de la astaxantina en la resistencia al estrés físico y químico de los langostinos jóvenes de Macrobrachium nipponense (Decapoda: Palaemonidae)

In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquacultureand its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense) fed diets containing different amounts of astaxanthin (AX) to the shock and stress of differentphysicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland) at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50mg/kg, AX100 with 100mg/kg, and AX150 with 150mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1 000L) used for holding prawns. Three replicate aquaria were initially stocked with 36org/m² per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5mg/L; and ammonia-nitrogen, 0.05mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C), ammonia (0.75mg/L), and reduced oxygen (0.5mg/L). The time to lethargyand the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed greater reduction than those exposed to other treatments. It is possible that higher levels of astaxanthin in the body under oxygen reduction stress can be beneficial forprawns. These results suggest that male prawns showed lethargy earlier than females, and the percentage of carotenoid reduction in muscle and gill tissues was higher inmales. Rev. Biol. Trop. 62 (4): 1331-1341. Epub 2014 December 01.

En años recientes, la utilización de nuevas técnicas científicas ha tenido un efecto importante en mejorar los procesos de producción en acuicultura. La astaxantina tiene varias propiedades en la acuicultura y sus propiedades antioxidantes se encuentran estrechamente relacionadas con la resistencia al estrés. La astaxantina en muchos crustáceos y peces es un factor esencial para el crecimiento. El objetivo de este estudio fue evaluar la resistencia del langostino (Macrobrachium nipponense) alimentado con dietas conteniendo diferentes cantidades de astaxantina (AX), bajo diferentes condiciones de estrés ambiental. Un ensayo de 70 días fue llevado a cabo para evaluar el efecto de la suplementación de fuentes de astaxantina (Carophyll Pink, 10 % astaxanthin) en varios niveles en la dieta de jóvenes de M. nipponense. Cuatro dietas fueron preparadas: AX0 sin astaxantina, AX50 con 50mg/kg, AX100 con 100mg/kg y AX150 con 150mg/kg de astaxantina. Los ensayos de alimentación fueron conducidos en un sistema de recirculación de agua consistente en 12 estanques de fibra de vidrio (1 000L). Tres replicas fueron sembradas con 36org/m2 por tanque. Durante el experimento los langostinos fueron mantenidos con un fotoperiodo de 12:12 luz:oscuridad con lámparas incandescentes y los parámetros de la calidad del agua fueron mantenidos a 25-26°C la temperatura, 1 g/L la salinidad, 8.5-8.8 el pH, 6.0-6.5 mg/L el oxígeno y 0.05mg/L el nitrógeno amoniacal. La incorporación de la astaxantina, producción y condiciones fisicoquímicas fueron registradas después de 10 semanas de alimentación. Al final del periodo de crecimiento, los langostinos fueron expuestos a un shock térmico (0°C), amonio (0.75mg/L) y reducción de oxígeno 0.5 mg/L. El tiempo de letargia y el tiempo de muerte fueron registrados. Se encontró que la dieta con la mayor concentración de astaxantina (150mg/kg) presentó el mayor tiempo de letargia y la mayor concentración en branquias y músculo en el langostino M. nipponense.

The effect of astaxanthin on resistance of juvenile prawns Macrobrachium nipponense (Decapoda: Palaemonidae) to physical and chemical stress.

In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquaculture and its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense) fed diets containing different amounts of astaxanthin (AX) to the shock and stress of different physicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland) at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50 mg/kg, AX100 with 100 mg/kg, and AX150 with 150 mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1000L) used for holding prawns. Three replicate aquaria were initially stocked with 36 org/m2 per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1 g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5 mg/L; and ammonia-nitrogen, 0.05 mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C), ammonia (0.75 mg/L), and reduced oxygen (0.5 mg/L). The time to lethargy and the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed greater reduction than those exposed to other treatments. It is possible that higher levels of astaxanthin in the body under oxygen reduction stress can be beneficial for prawns. These results suggest that male prawns showed lethargy earlier than females, and the percentage of carotenoid reduction in muscle and gill tissues was higher in males.

Effects of propofol on damage of rat intestinal epithelial cells induced by heat stress and lipopolysaccharides

Gut-derived endotoxin and pathogenic bacteria have been proposed as important causative factors of morbidity and death during heat stroke. However, it is still unclear what kind of damage is induced by heat stress. In this study, the rat intestinal epithelial cell line (IEC-6) was treated with heat stress or a combination of heat stress and lipopolysaccharide (LPS). In addition, propofol, which plays an important role in anti-inflammation and organ protection, was applied to study its effects on cellular viability and apoptosis. Heat stress, LPS, or heat stress combined with LPS stimulation can all cause intestinal epithelial cell damage, including early apoptosis and subsequent necrosis. However, propofol can alleviate injuries caused by heat stress, LPS, or the combination of heat stress and LPS. Interestingly, propofol can only mitigate LPS-induced intestinal epithelial cell apoptosis, and has no protective role in heat-stress-induced apoptosis. This study developed a model that can mimic the intestinal heat stress environment. It demonstrates the effects on intestinal epithelial cell damage, and indicated that propofol could be used as a therapeutic drug for the treatment of heat-stress-induced intestinal injuries.