Effects of heat stress on HSP70 and Na+/K+-ATPase expressions in the gills of juvenile goldfish: Focus on tissue architecture, mucus secretion and protein nitration.

In this study, we examined the dose-dependent effects of an environmentally relevant pesticide cocktail (metalachlor, linuron, isoproturon, tebucanazole, aclonifen, atrazine, pendimethalin, and azinphos-methyl) and temperature change (22 vs. 32°C for 4-week exposure) on Na+/K+-ATPase, 3-nitrotyrosine protein (NTP), dinitrophenyl protein (DNP), catalase (CAT), and superoxide dismutase (SOD) expressions in gills of goldfish (Carassius auratus). Histopathological analysis showed widespread damage to gill in elevated temperature (32°C) and pesticide co-exposure groups, including fusion of secondary lamellae, club-shaped primary lamellae, rupture of epithelial layer, loss of normal architecture, and hemorrhaging. Immunohistochemical and qRT-PCR analyses showed significant decreases in Na+/K+-ATPase protein and mRNA expressions in gills exposed to higher temperature and pesticides; however, combined exposure to heat and pesticides significantly increases NTP, DNP, CAT, and SOD expressions. In situ TUNEL assay revealed elevated levels of apoptotic cells in response to combined exposure. Collectively, our results suggest the combined effects of heat and pesticide stress cause cellular damage, upregulate oxidative/nitrative stress biomarkers, and increase apoptotic cells, downregulate Na+/K+-ATPase expression in gills. This provides new evidence for oxidant/antioxidant-dependent mechanisms for downregulation of Na+/K+-ATPase expression in gills during combined exposure.

Roundup® disrupts tissue architecture, attenuates Na+/K+-ATPase expression, and induces protein oxidation/nitration, cellular apoptosis, and antioxidant enzyme expressions in the gills of goldfish, Carassius auratus

Extreme temperature events as a consequence of global climate change result in a significant decline in rice production. A two-year phytotron experiment was conducted using three temperature levels and two heating durations to compare the effects of heat stress at booting, flowering, and combined (booting + flowering) stages on the production of photosynthates and yield formation. The results showed that high temperature had a significant negative effect on mean net assimilation rate (MNAR), harvest index (HI), and grain yield per plant (YPP), and a significant positive effect under treatment T3 on mean leaf area index (MLAI) and duration of photosynthesis (DOP), and no significant effect on biomass per plant at maturity (BPPM), except at the flowering stage. Negative linear relationships between heat degree days (HDD) and MNAR, HI, and YPP were observed. Conversely, HDD showed positive linear relationships with MLAI and DOP. In addition, BPPM also showed a positive relationship with HDD, except at flowering, for both cultivars and Wuyunjing-24 at combined stages. The variation of YPP in both cultivars was mainly attributed to HI compared to BPPM. However, for biomass, from the first day of high-temperature treatment to maturity (BPPT-M), the main change was caused by MNAR followed by DOP and then MLAI. The projected alleviation effects of multiple heat stress at combined stages compared to single-stage heat stress would help to understand and evaluate rice yield formation and screening of heat-tolerant rice cultivars under current scenarios of high temperature during the rice-growing season.

Effect of season and temperature before and after calving on the future milk production of born heifers

Even though high temperatures significantly reduce both vegetative growth and yield in cotton, very little is known about the effects of heat stress on cotton antioxidant system. Thus, the effects of gradual heat stress on cotton growth in controlled conditions were investigated in the present study. At squaring stage, cotton plants were subjected to two different temperatures, 38 and 45°C to determine the influence of heat stress on the plants. The results of the present study showed that heat stress did not significantly altered the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the leaves, whereas there was a remarkable decline in proline quantity of the leaves of plants subjected to 45°C heat stress. As for the amount of total chlorophyll content, a slight increase at plants treated with 38°C temperature was observed. Furthermore, the activities of some enzymes such as superoxide dismutase (SOD), which were associated with heat stress response in other plants was also investigated. For example, there was decline in the activitity ofSOD in the plants exposed to high temperatures. On the contrary, catalase (CAT)activity increased at 45°C; peroxidase (POX) activity increased at 38°C and ascorbate peroxidase (APX) activity increased at 38 and 45°C. The results from this study suggest a potential role for CAT, POX and APX in the reduction of elevated levels of H2O2 in cotton plants grown under heat stress condition. To sum up, it could be concluded that, diurnal gradual heat stress caused a low oxidative injury in cotton. Key words: Antioxidant enzymes, cotton, heat stress, lipid peroxidation, proline.

Seasonal and acute heat stress effects on steroid production by dominant follicles in cows.

The simultaneous occurrence of heat stress and drought is becoming more regular as a consequence of climate change, causing extensive agricultural losses. The application of either heat or osmotic stress increase cell-wall suberization in different tissues, which may play a role in improving plant resilience. In this work, we studied how the suberization process is affected by the combination of drought and heat stress by following the expression of suberin biosynthesis genes, cell-wall suberization and the chemical composition in Arabidopsis roots. The Arabidopsis plants used in this study were at the onset of secondary root development. At this point, one can observe a developmental gradient in the main root, with primary development closer to the root tip and secondary development, confirmed by the suberized phellem, closer to the shoot. Remarkably, we found a differential response depending on the root zone. The combination of drought and heat stress increased cell wall suberization in main root segments undergoing secondary development and in lateral roots (LRs), while the main root zone, at primary development stage, was not particularly affected. We also found differences in the overall chemical composition of the cell walls in both root zones in response to combined stress. The data gathered showed that, under combined drought and heat stress, Arabidopsis roots undergo differential cell wall remodeling depending on developmental stage, with modifications in the biosynthesis and/or assembly of major cell wall components.

High temperatures in hot regions and summer months impair the yield and productivity of laying hens. In this study, it is aimed to give detailed information about the measures to be taken to reduce the losses to the effects of heat stress on the yield and productivity of laying hens. Heat stress is one of the most challenging problems that affect all parameters of production performance and productivity, leading to high mortality rates and significant economic losses in commercial laying hens’ production due to inhibition of immune responses. It manifests itself with neurological symptoms such as high body temperature, hot-dry skin, paralysis, headache and loss of consciousness. It causes death as a result of heat cramps and stroke. In addition, heat stress disrupts the reproductive hormones of female-male laying hens. It causes infertility in male by reducing the number and movement of viable sperm. The effect of heat stress depends on age, sex, body weight, relative humidity and length of stay at high temperature. The temperature should not exceed 24°C for optimum egg yield and quality, and 27°C for welfare and productivity. Above this temperature, rapid breathing, the problem of not emitting heat from their bodies to the environment, decrease in feed consumption and live weight gain begin to be seen in chickens. At high temperatures, 34-35°C, egg production decreases by approximately 30% and feed intake decreases by 30-50%. As a result, measures such as feed management against heat stress, adding heat stress reducing additives to feed and water, climatic environmental control in shelters, early life conditioning and genetic selection of breeds with increased capacity of coping with heat stress conditions can be taken.

Animals exposed to high ambient temperatures (AT) suffer from heat stress (HS), which provokes physiological and metabolic changes. HS seems to affect the gastro intestinal tract integrity hence affecting absorption capacity. An experiment was conducted with 18 pigs (32.4±2.7 kg BW) to examine the effect of natural severe HS (AT up to 45 °C) on expression of amino acid (b0,+, CAT1) and glucose (SLC2A1, GLUT4) transporters in duodenum, jejunum, liver, and Longisimus (LDM) and Semitendinosus (STM) muscles. Treatments (T) were: T1, comfort pigs housed in AT controlled room (22±2 °C) and fed ad libitum (C‐AL); T2, pigs housed as in T1, but feed‐restricted (C‐FR); T3, pigs housed in a room with no climate control (AT raised up to 45 °C; HS). HS pigs consumed about 95% of their ad libitum feed intake, and feed intake of C‐FR was similar to that of HS pigs. All pigs received the same diet and purified water. HS increased relative expression of CAT‐1 (P=0.043) in liver, but reduced it in LDM (P=0.007). HS increased duodenal expression of SLC2A1 (P=0.041), and that of GLUT4 (P=0.063) in STM. Severe HS affects the expression of glucose and amino acid transporters in selected pig tissues.Grant Funding Source: Supported by CONACYT‐México

Effects of high temperature during grain filling on physicochemical properties of waxy maize starch

Submitted 2020-07-03 | Accepted 2020-09-09 | Available 2020-12-01 https://doi.org/10.15414/afz.2020.23.mi-fpap.167-173 Global warming is already affecting several areas and a further increase of 1.5°C is expected by 2050. Dairy cattle are particularly sensitive to high temperature. So, the aim of this study was to examine the effect of temperature-humidity index (THI) on milk traits, considering changes of climatic parameters in the different seasons from 2010 to 2018. The study was conducted in 3 farms located in a hilly-mountainous area of Tuscany, the Mugello, situated from 220 to 450 m above sea level. Data on average daily milk yield and composition were monthly collected in the 3 farms from 2010 to 2018, while climatic parameters were recorded by a climatic station located in the area of the farms. As regards the climatic parameters, no significant variations have been observed in the last decade. The THI calculated thanks to the recording of temperature and humidity of the weather station, during the warmest months, was high enough to cause heat stress. The milk quality traits declined when THI increased. In conclusion, there was not any evidence that global warming has been affecting Mugello, but, despite its altitude, high THI usually reached during spring and summer seasons are already high enough to cause heat stress and a further increase could worsen farm productivity. Keywords: climate change, milk quality, heat stress, dairy cow References Amamou, H. et al. (2019). Thermotolerance indicators related to production and physiological responses to heat stress of Holstein cows. Journal of Thermal Biology, 82, 90–98. https://doi.org/10.1016/j.jtherbio.2019.03.016 André, G. et al. (2011). Quantifying the effect of heat stress on daily milk yield and monitoring dynamic changes using an adaptive dynamic model. Journal of Dairy Science, 94(9), 4502–4513. https://doi.org/10.3168/jds.2010-4139 Bartolini, G. et al. (2012). Mediterranean warming is especially due to summer season. Theoretical and Applied Climatology, 107, 279–295. https://doi.org/10.1007/s00704-011-0481-1 Baumgard, L. H. and Rhoads, R. P. (2007). The effects of hyperthermia on nutrient partitioning. In: Proceedings of Cornell Nutrition Conference, Ithaca, New York, 93–104. Bertocchi, L. et al. (2014). Seasonal variations in the composition of Holstein cow’s milk and temperature-humidity index relationship. Animal, 8(4), 667–674. https://doi.org/10.1017/S1751731114000032 Bohmanova, J., Misztal, I. and Cole, J. B. (2007). Temperature-humidity indices as indicators of milk production losses due to heat stress. Journal of Dairy Science, 90(4), 1947–1956. https://doi.org/10.3168/jds.2006-513 Bouraoui, R. et al. (2002). The relationship of temperature-humidity index with milk production of dairy cows in a Mediterranean climate. Animal Research, 51(6), 479–491. https://doi.org/10.1051/animres:2002036 Das, R. et al. (2016). Impact of heat stress on health and performance of dairy animals: A review. Veterinary World, 9(3), 260–268. https://doi.org/10.14202/vetworld.2016.260-268 Fabris, T. F. et al. (2019). Effect of heat stress during early, late, and entire dry period on dairy cattle. Journal of Dairy Science, 102(6), 5647–5656. https://doi.org/10.3168/jds.2018-15721 Gauly, M. and Ammer, S. (2020). Review: Challenges for dairy cow production systems arising from climate changes. Animal, 14(S1), S196–S203. https://doi.org/10.1017/S1751731119003239 Hossein-Zadeh, N. G., Mohit, A. and Azad, N. (2013). Effect of temperature-humidity index on productive and reproductive performances of Iranian Holstein cows. Iranian Journal of Veterinary Research 14(2), 106-112. https://dx.doi.org/10.22099/ijvr.2013.1583 Herbut, P., Angrecka, S. and Godyń, D. (2018). Effect of the duration of high air temperature on cow’s milking performance in moderate climate conditions. Annals of Animal Science, 18(1), 195–207. https://doi.org/10.1515/aoas-2017-0017 Javed, K. et al. (2004). Environmental factors affecting milk yield in Friesian cows in Punjab, Pakistan. Pakistan Veterinary Journal, 24, 4-7. Polsky, L. and von Keyserlingk, M. A. G. (2017). Invited review: Effects of heat stress on dairy cattle welfare. Journal of Dairy Science, 100(11), 8645–8657. https://doi.org/10.3168/jds.2017-12651 Renaudeau, D. et al. (2012). Adaptation to hot climate and strategies to alleviate heat stress in livestock production. Animal, 6(5), 707–728. https://doi.org/10.1017/S1751731111002448 Rhoads, M. L. et al. (2009). Effects of heat stress and plane of nutrition on lactating Holstein cows: I. Production, metabolism, and aspects of circulating somatotropin. Journal of Dairy Science, 92(5), 1986–1997. https://doi.org/10.3168/jds.2008-1641 Rojas-Downing, M. M. et al. (2017). Climate change and livestock: Impacts, adaptation, and mitigation. Climate Risk Management, 16, 145–163. https://doi.org/10.1016/j.crm.2017.02.001 Silanikove, N. and Koluman, D. N. (2015). Impact of climate change on the dairy industry in temperate zones: Predications on the overall negative impact and on the positive role of dairy goats in adaptation to earth warming. Small Ruminant Research, 123(1), 27–34. https://doi.org/10.1016/j.smallrumres.2014.11.005 Spiers, D. E., et al. (2004). Use of physiological parameters to predict milk yield and feed intake in heat-stressed dairy cows. Journal of Thermal Biology, 29(7-8 SPEC. ISS.), 759–764. https://doi.org/10.1016/j.jtherbio.2004.08.051 Thornton, P. K. et al. (2009). The impacts of climate change on livestock and livestock systems in developing countries: A review of what we know and what we need to know. Agricultural Systems, 101(3), 113–127. https://doi.org/10.1016/j.agsy.2009.05.002 Zampieri, M. et al. (2016). Global assessment of heat wave magnitudes from 1901 to 2010 and implications for the river discharge of the Alps. Science of the Total Environment, 571, 1330–1339. https://doi.org/10.1016/j.scitotenv.2016.07.008 Â

Grow-finish pigs (n = 192) were used in a 28-day experiment to determine if adding oregano essential oil to the water would mitigate the detrimental effects of heat stress. Pigs (initial BW = 51.9 kg) were blocked by sex and BW and randomly allotted to a 2x2 factorial arrangement of water treatment (oregano essential oil vs. control) and environment (heat stress vs. thermoneutral). There were 6 pigs/pen (4 barrows and 2 gilts/pen) and 8 pens/treatment. Pigs were given 15 d to acclimate to pens and water treatment under thermoneutral conditions (21.1℃). Following acclimation, one-half the pigs were subjected to a 3-day diurnal heat stress (12 h at 33.3℃ and 12 h at 26.7℃). On d 22 of the experiment (3 d post-heat stress), one barrow/pen was euthanized; jejunal mucosa scrapings were collected, flash frozen in liquid nitrogen, and stored at -80oC for subsequent RNA isolation and cDNA creation. Gene expression of CDKN1A, TP53, GPX1, SOD1, SLC2A2, SLC2A5, and MUC2 were determined by qPCR using SYBR green, normalized using housekeeper genes and expressed relative to the control treatment using the 2-ΔΔCT method. Data were analyzed as RCB using GLM procedure in SAS 9.4 with fixed effects of water treatment, environment, and the interaction. Heat-stressed pigs had reduced ADG (P < 0.003) and Gain:Feed (P < 0.008) during the 3d heat stress compared with pigs housed in thermoneutral conditions. Post-heat stress, ADG (P < 0.001) and Gain:Feed (P < 0.001) increased in previously heat-stressed pigs compared with thermoneutral pigs. There was no effect of oregano supplementation before or during heat stress. However, in the post-heat stress period, ADG was increased (P < 0.05) by oregano supplementation in the water for both heat stressed and non-heat stressed pigs. Oregano supplementation did not affect ADFI before heat stress. An interaction (P < 0.005) of heat stress and water treatment was observed for ADFI during heat stress and after heat stress. During heat stress, oregano supplementation resulted in reduced feed intake. Post-heat stress ADFI was lowest for non-heat stressed pigs with no oregano supplementation. Oregano essential oil increased water consumption before (P < 0.02), during (P < 0.03), and after heat stress (P < 0.02), with an overall increase in water consumption of 35% compared with control pigs (P < 0.04). No interactions of heat stress and oregano supplementation were observed for gene expression. SLC2A2 expression tended (P < 0.08) to be downregulated when oregano essential oils were added to the water and upregulated following an acute heat stress. SLC2A5 expression was increased in pigs given oregano compared with control pigs (P < 0.02), but was unaffected by heat stress. Water delivered oregano essential oil increased water intake and had a slight effect on intestinal gene expression but did not mitigate the effects of a short-term heat stress.

Effects of long-time and short-time heat stress on the meat quality of geese

Heat stress and N fertilization affect soil microbial and enzyme activities in the creeping bentgrass (Agrostis Stolonifera L.) rhizosphere

Effect of heat stress on peroxidase activity and total protein content in strawberry plants