Submitted by Eraldo Laerte Drago Filho null (eraldinhodrago@hotmail.com) on 2017-08-14T02:04:03Z No. of bitstreams: 1 Dissertação Eraldo Pós Defesa final jul 2017.pdf: 735320 bytes, checksum: d7cea9d3ac82606ae1d91cd0853fd717 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-08-18T19:54:39Z (GMT) No. of bitstreams: 1 dragofilho_el_me_bot.pdf: 735320 bytes, checksum: d7cea9d3ac82606ae1d91cd0853fd717 (MD5) / Made available in DSpace on 2017-08-18T19:54:39Z (GMT). No. of bitstreams: 1 dragofilho_el_me_bot.pdf: 735320 bytes, checksum: d7cea9d3ac82606ae1d91cd0853fd717 (MD5) Previous issue date: 2017-07-24 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo do experimento foi avaliar a temperatura vaginal em parâmetros produtivos e reprodutivos. Vacas Holandesas lactantes n = 641 (209 primíparas 36,9 ± 6,54 kg de leite / d; 432 multíparas 43,9 ± 9,77 kg de leite / d) tiveram a temperatura vaginal monitorada através de termômetros, anexados a um dispositivo intravaginal como parte de um protocolo de IATF. A temperatura vaginal foi registrada a cada 10 minutos durante três dias. A temperatura ambiente e a umidade relativa (ITU) foram mensuradas usando um termômetro externo colocado dentro do barracão. Os dados foram analisados com SAS 9.4 usando correlação de Pearson, ANOVA e regressão logística. Calculou-se o estresse térmico com base na porcentagem de tempo que a vaca ficou com uma temperatura vaginal ≥ 39,1°C (PCT). As vacas foram classificadas através de quartis (AltaPCT (3º quartil; PCT-60%) e BaixaPCT; PCT-16%) para PCT e o mediana para produção de leite, que eram diferentes para primíparas e multíparas. Houve uma baixa correlação entre ITU e produção de leite com PCT (r = 0,01), indicando maior variação na termorregulação. O BaixaPCT (22,4 e 13,9%) e o AltaPCT (12,6 e 9,7%) reduziram significativamente o P/AI no dia 30 e 52 pós-IA (P < 0,01) e sem interações com ordem, escore de condição corporal e ITU observados. A cor da pelagem e a espessura do couro não influenciaram o PCT (P > 0,1). Entretanto houve interação entre cor de pelagem, PCT e produção de leite, onde independente da PCT e produção de leite, vacas de cor branca apresentaram menor prenhez (P = 0,03). Em resumo, houve uma grande variabilidade em como as vacas respondem individualmente ao estresse térmico. A prenhez foi afetada somente em vacas com alta PCT independente da ordem, produção de leite, ECC. A seleção de animais com controle eficiente da temperatura corporal apesar da alta produção de leite deve ser abordada como uma estratégia para manter a fertilidade adequada. / The aim of the experiment was to evaluate vaginal temperature on productive and reproductive traits and potential genetic contribution to thermomtolerance. Lactating Holstein cows n = 641 (209 primíparous 36,9 ± 6,54 kg milk/d; 432 multíparous 43,9 ± 9,77 kg milk/d) had vaginal temperature monitored using thermometers, attached to an intravaginal device as part of a timed-AI protocol and recorded vaginal temperature every 10 minutes for 3 days. Ambient temperature and relative humidity (THI) were monitored using an external thermometer placed inside the barn. The data were analyzed with SAS 9.4 using Pearson correlation, ANOVA and logistic regression. Heat stress was calculated based on the percentage of time the cow spent with a vaginal temperature ≥39,1°C (PCT). Cows were classified using the 75th percentile threshold (HighPCT and LowPCT) for PCT and the median value for milk, which were different for primiparous and multiparous. There was a low correlation between THI and milk production with PCT (r=0,01) indicating a large variation in thermoregulation. Multiparous LowPCT (22,4 and 13,9%) and HighPCT (12,6 and 9,7%) significantly reduced P/AI on day 30 and 52 post-AI (P < 0,01) and no interactions with parity, body condition score and THI were observed. Coat color and skin thickness did not influenced PCT. However, there was interaction between coat color, where, independent of PCT and milk production, white cows presented lower pregnancy rate (P < 0,03). In summary, there is a large variability on how individual cows respond to heat stress. Pregnancy was just affected in cows with high PCT independent of parity, milk production, BCS. Selection of animals with efficient control of body temperature in spite of high milk production should be further approached as a strategy to maintain adequate fertility. / CNPq: 131628/2015-1

Orientador: Silvia Helena Venturoli Perri / Coorientador: Manoel Garcia Neto / Banca: Antonio Carlos Laurentiz / Banca: Guilherme de Paula Nogueira / Resumo: O estresse calórico é o agente desencadeador de diversos distúrbios metabólicos em frangos de corte, entre eles o desequilíbrio ácido- base. Com a finalidade de evitar esses efeitos e melhorar o desempenho dos animais, faz-se necessário a utilização de níveis adequados de eletrólitos e, também, uma correta proporção entre esses na ração, obtendo assim uma formulação com um equilíbrio eletrolítico apropriado para os animais. Assim, o presente trabalho teve como objetivo avaliar o desempenho e a mortalidade de frangos de corte submetidos a diferentes balanços (Na++K+-Cl-)e relações eletrolíticas [(K++Cl-)/Na+] na dieta em condições de termoneutralidade e sobre estresse térmico. Para tanto um primeiro experimento foi realizado com um total de 1575 pintos de corte machos de 1-21, em condições termoneutras, em que os tratamentos consistiam de cinco dietas decorrentes de combinações BE/RE (150/3, 250/2, 250/3, 250/4 e 350/3). Foram avaliados os parâmetros peso corporal, consumo de ração e conversão alimentar, os quais se apresentaram sensíveis aos níveis de suplementação de BE e RE, enquadrados numa análise de superfície que permitiu melhor avaliação dos crescentes níveis de BE e relação estreita e larga do RE. Os resultados indicaram que o melhor desempenho foi obtido somente com as combinações simultâneas de eletrólitos para BE entre 251 e 255mEq/kg e RE entre 2,73:1 e 3,5:1. Em um segundo experimento, foram utilizados os mesmos animais, porém de 21-46 dias de idade, distribuídos em arranjo fatorial 5x3, totalizando 15 tratamentos. Os tratamentos consistiram das mesmas cinco dietas com diferentes combinações entre BE e RE, associado com a aplicação do estresse por calor, no 25° ou 35° dia de idade. Foi possível verificar que a formulação estratégica do correto equilíbrio de eletrólitos melhora o desempenho e é capaz de evitar o efeito do estresse / Abstract: The heat stress is the causative agent of several metabolic disorders in broiler chickens, including the acid-base imbalance. In order to avoid these effects and improve animal performance, it is necessary to use adequate levels of electrolytes and also a correct proportion of these in the diet, thereby obtaining a formulation with an appropriate electrolyte balance for the animals. Thus, this study aimed to evaluate the performance and mortality of broilers submitted to different balances Na++K+-Cl-) and relations electrolyte [(K++Cl-)/Na+] in the diet at thermoneutrality and on thermal stress. Therefore, a first experiment was conducted with a total of 1575 male broiler chicks of 1-21 in thermoneutral conditions, in which treatments consisted of five diets resulting from combinations BE/RE (150/3, 250/2, 250/3, 250/4 and 350/3). The parameters evaluated were body weight, feed intake and feed conversion, which were susceptible to dietary supplementation of BE and RE, embedded in a surface analysis which allowed a better assessment of rising levels of BE and close and wide-RE. The results indicated that the best performance was obtained only with simultaneous combinations of electrolytes to between 251 and 255mEq/kg BE and RE and between 3,5:1-2,73:1. In a second experiment, we used the same animals, but in 21-46 days of age in a factorial arrangement 5x3, totaling 15 treatments. The treatments were the same five diets with different combinations of BE and RE, together with the application of heat stress on the 25th or 35th day of age. It was possible to verify that the correct formulation of the strategic balance of electrolytes improves performance and is able to avoid the effect of heat stress in broilers, whereas a diet with BE of 250 mEq/kg and RE 3 for better performance and a diet with BE of 350 mEq/kg and 3 RE aimed at survival of animals / Mestre

O objetivo deste estudo foi avaliar a tolerância ao calor de ovinos de corte das raças Santa Inês, Dorper e Merino Branco através do teste de capacidade termolítica (exposição ao sol). Foram utilizadas um total de 97 fêmeas vazias, com idade média de 3 anos. O estudo decorreu no verão, onde foram registradas as variáveis fisiológicas temperatura retal (TR), temperatura superficial (TS), frequência respiratória (FR), mensuradas depois de duas horas sob a sombra (1), uma hora sob o sol (2), quinze (3) e trinta (4) minutos após a exposição ao sol, e a taxa de sudação (Sud), no tempo 2. Posteriormente foram realizadas observações de comportamento a pasto durante três dias, no período das 11 às 14 horas, para as variáveis: tempo ao sol; tempo em pé; pastejo/alimentação, ruminação e ócio. As médias de TR1 foram semelhantes para as ovelhas Santa Inês e Dorper e superior para as ovelhas Merino Branco (P&lt;0,05). Para TR2, TR3 e TR4 as ovelhas da raça Merino Branco tiveram os maiores valores, seguidos das ovelhas da raça Santa Inês e com os menores aumentos de temperatura retal nas ovelhas da raça Dorper (P&lt;0,05). Estes resultados refletiram na capacidade termolítica individual, sendo menor para a raça Santa Inês (P&lt;0,05). Após exposição ao sol observaram-se diferenças entre as TS, sendo as da raça Merino Branco mais elevadas, seguidas pelas da raça Dorper e da Santa Inês (P&lt;0,05). A raça Merino Branco apresentou as maiores FR, seguida das raças Dorper e Santa Inês, todas diferentes entre si (P&lt;0,05). Todos os animais expostos por uma hora ao sol apresentaram aumento nas TR, TS e FR (P&lt;0,05), e se aproximaram dos níveis encontrados antes da exposição ao sol após trinta minutos de descanso sob a sombra (Santa Inês e Dorper P&lt;0,05; Merino Branco P&gt;0,05). A taxa média de sudação para as ovelhas da raça Santa Inês foi superior a encontrada para as ovelhas da raça Dorper (P&lt;0,05). Houve diferença entre os animais dentro de cada raça (P&lt;0,05), confirmando a hipótese de grande variabilidade entre os indivíduos e diferenças entre as raças. Com relação ao comportamento, as ovelhas da raça Santa Inês continuaram em pastejo mesmo nas horas mais quentes do dia, tendo sido encontrada uma correlação positiva de 0,64 entre a capacidade termolítica individual e o pastejo ao sol, enquanto as ovelhas da raça Dorper preferencialmente permaneceram à sombra devido ao manejo semiconfinado. No presente trabalho o tipo de manejo alimentar influenciou no tempo de uso da sombra. Sob as condições climáticas encontradas no experimento os animais estudados tiveram seus parâmetros fisiológicos alterados devido à exposição ao sol, e os animais das raças Dorper e Merino Branco mostraram maior capacidade termolítica do que os animais da raça Santa Inês, sendo este um fator que pode influenciar na tolerância ao calor individual. / The aim of this study was to evaluate the heat tolerance of three meat sheep breeds, Santa Ines, Dorper and White Merino using Thermolysis capacity test. 97 non pregnant females (3 years old) were used in the study that took place in the summer. Physiological variables as rectal temperature (RT), surface temperature (ST), respiratory rate (RR) were measured after two hours under the shade (1), after one hour under the sun (2), fifteen (3) and thirty (4) minutes after sun exposure, and sweating rate (SR) on time 2. Were also collected behavioral data during three days in the period from 11:00 to 14:00 hours: say in the sun, standing posture, eating, ruminating and idling. RT1 means were equal Santa Ines and Dorper, and greater for White Merino (P&lt;0.05). White Merino also had greater values for RT2, RT3 e RT4, followed by Santa Ines and Dorper (P&lt;0.05). These results reflected the thermolysis capacity, being lower for Santa Ines breed (P&lt;0.05). After sun exposure differences between ST were observed, and greater values were found for White Merino, followed by Dorper and Santa Ines breeds (P&lt;0.05). In the same way, White Merino had the highest RR, followed by Dorper, which had higher RR compared to Santa Ines (P&lt;0.05). All animals exposed to the sun for an hour showed increased RT, ST, RR values (P&lt;0.05), and approached the levels found before exposure to the sun after thirty minutes of rest in the shade (Santa Ines and Dorper P&lt;0.05; White Merino P&gt;0.05). Sweating rate for Santa Ines breed was higher than those found for Dorper breed (P&lt;0.05). There were differences among animals within each race (P&lt;0.05), confirming the hypothesis of great variability among individuals and differences between the breeds. With respect to behavior, Santa Ines ewe grazed even during the hottest hours of the day, and a positive correlation of 0.64 between the individual thermolysis capacity and grazing in the sun was found, while the Dorper ewes remained preferentially under the shade due to the semi-confined management. In the present study, feedin management influenced the time under the shade. Under experimental climatic conditions, the studied ewes had theirs physiological parameters increased due to sun exposure, and Dorper and White Merino breeds showed a greater thermolisys capacity than the animals of the Santa Ines breed, which is a factor that can influence individual heat tolerance.

Master of Science in Biomedical Sciences / Department of Clinical Sciences / Robert L. Larson / Bradley J. White / Feedlot cattle frequently endure high environmental temperature-humidity index conditions in the summer months within cattle feeding regions of North America. Heat stress develops when the total heat gain (combined effects of environmental and metabolic factors) exceeds an animal’s heat loss capabilities. The objective of my research was evaluating heat mitigation strategies and developing a practical method to identify animals that are of greatest risk of heat stress; thus improving animal welfare and performance. A number of heat abatement strategies have been utilized in US feedlots including shade, sprinklers, nutritional modifications, and misters. A literature review was performed using published journal articles demonstrated significant benefits of providing shade to feedlot cattle. Sprinkling the pen surface may be just as beneficial as sprinkling or misting cattle. Sprinkling the ground not only cooled the ground which increased the thermal gradient between lying cattle and the ground, but also provided increased thermal conductivity and better heat flow down that gradient. A study was performed to develop a noninvasive, remotely applied, practical method to identify animals at risk for heat stress. Infrared thermography images were obtained during the morning hours and pant scores obtained in the afternoon hours. Data mining techniques were employed to evaluate accuracy of potential classification methods to identify heat stress events in the afternoon based on the known morning data. Using infrared technology as a diagnostic test was not accurate for predicting heat stress events in the study presented. Finally a retrospective study of Kansas feedlot performance, medical and weather data was performed. Findings indicate that diagnostic counts of bovine respiratory disease are associated with elevated ambient temperature two days prior. In conclusion, heat stress in beef feedlot animals is an important area of research. Heat mitigation methods such as shade have been proven to be effective at reducing heat stress in beef feeder cattle. Further research is needed to evaluate the use of infrared technology to predict heat stress events in the feedlot setting.

The objective of this study was to evaluate the effect of pregnancy, breed, and hair coat on body temperature and sweating rate (SR) of hair sheep. St. Croix White (STX; = 9) and Dorper × STX (DRPX; = 9) ewes (3.6 yr of age) were evaluated over 4 d at 126 d of gestation (PREG) and over 4 d at 46 d postpartum (OPEN) in the shade and sun and in the morning (AM; 0900 to 1200 h) and afternoon (PM; 1300 to 1600 h) after a 20 min acclimation to each condition on each day. Data loggers recorded vaginal temperature (VT) at 10-min intervals for 96 h. Rectal temperature (RT) was measured using a digital veterinary thermometer, and respiration rate (RR) was measured as breaths per minute (bpm). Sweating rate was calculated from measured air properties passing over a shaved (300 cm) and unshaved area of the ewes' body using a portable calorimeter. Data were analyzed using GLM procedures of SAS (SAS Inst. Inc., Cary, NC) with breed, pregnancy status, sun exposure, and time of day as main effects. Mean temperature, relative humidity, temperature-humidity index, wind speed, and solar radiation on the days of data collection were 28.2°C, 82.8%, 80.3, 4.2 km/h, and 237.5 W/m, respectively. There was no difference ( > 0.10) in RT, RR, and SR between DRPX and STX ewes. The PREG ewes had lower RT ( < 0.007) and SR ( < 0.0001) and higher RR ( < 0.007) than OPEN ewes (38.5 ± 0.2 vs. 39.1 ± 0.2°C, 70.2 ± 3.1 vs. 88.3 ± 3.1 g⋅m⋅h, and 79.5 ± 2.2 vs. 72.1 ± 2.2 bpm, respectively). During the PM, RR, RT ( < 0.05), and SR ( < 0.006) were higher than in the AM. In the sun, RR ( < 0.001) and SR ( < 0.0001) were higher than in the shade, but there was no difference ( > 0.10) in RT. There was no difference in SR ( > 0.10) between the shaved and unshaved area of the ewe. The DRPX ewes had higher ( < 0.0001) VT than STX ewes. The PREG ewes had higher ( < 0.001) VT than OPEN ewes during the night time and lower VT than the OPEN ewes during the day time ( < 0.0001). The OPEN ewes had a greater ( < 0.009) daily range of VT than PREG ewes did (2.5 ± 0.4 vs. 1.1 ± 0.4°C, respectively), but there was no breed difference ( > 0.10). Hair coat did not have an influence on the SR of the ewes, and PREG ewes appeared to use increased respiration as opposed to sweating to help control RT. The narrower range of body temperature, measured as VT, of PREG compared to OPEN ewes may be a protective mechanism for the developing fetus.

Current knowledge indicates that nonthermal muscle metaboreflex activity plays a critical role in the modulation of skin vasodilation and sweating. However, the mechanisms of control have primarily been studied during isometric handgrip exercise in which muscle metaboreceptor activation is induced by a brief post-exercise ischemia of the upper limb. While the reflex increase in mean arterial pressure associated with this period of ischemia is consistent with the activation of muscle metaboreceptors, the change in baroreflex activity may in itself modulate the response. Thus, we sought to understand how these nonthermal stimuli interact in modulating the control of skin perfusion and sweating under conditions of elevated hyperthermia. Furthermore, we examined the mechanisms responsible for the maintenance of arterial blood pressure under varying levels of heat stress during isometric handgrip exercise. Our study findings indicate that the parallel activation of muscle metaboreceptors and baroreceptors during post-exercise ischemia causes divergent influences on the control of skin blood flow and sweating; and these nonthermal stimuli are dependent on the level of hyperthermia. Moreover, we report that heat stress reduces the increase in arterial blood pressure during isometric handgrip exercise and this attenuation is attributed to a blunted increase in peripheral resistance, since cardiac output increased to similar levels for all heat stress conditions. These results provide important insight and understanding into the role of muscle metabo- and baroreflex activity on the control of skin blood flow and sweating; along with further knowledge into the cardiovascular mechanisms responsible for the regulation of arterial blood pressure during hyperthermia.

Coral reefs are the most diverse marine ecosystems of significant ecological and economic importance, globally. Increasing environmental stress imposed by global warming, ocean acidification and pollution has led to the continuous decline of coral reefs. For reefs to thrive and survive, they rely on the stable endosymbiosis between coral animal and photosynthetic algae. The fragile symbiotic relationship is dependent on a balanced metabolic exchange, which is easily disturbed by stress, consequently leading to the loss of the endosymbiotic algae - a process known as bleaching. Since corals energetically rely on the algae, the breakdown of symbiosis can have fatal consequences. However, the underlying molecular and cellular mechanisms of this symbiosis are thus far poorly understood. The small sea anemone Aiptasia has provided an experimentally tractable model organism, furthering our understanding on the function of symbiosis and hence, coral susceptibility and resilience to stress. Nonetheless, this model organism is comparatively young and therefore, requires innovative approaches as well as establishment and optimization of protocols. In this thesis, we applied transcriptomic, proteomic and epigenomic tools in Aiptasia, with the aim to assess the dynamics of symbiosis and thermotolerance. Heat stress studies, on Aiptasia's originating from geographically distinct regions, provided insight into the cnidarian-algae symbiosis mechanisms and the role of metabolic compatibility in symbiosis. Furthermore, findings elucidated that associating with thermotolerant algae can improve the cnidarian host's tolerance, potentially acting as a form of local adaptation. Finally, the role of epigenetic mechanisms in cnidarian symbiosis was investigated, by optimizing Chromatin Immunoprecipitation (ChIP) and establishing the genomic landscape of histone 3 lysine 9 acetylation (H3K9ac) in Aiptasia. These new results will enable progressing Aiptasia further as a model organism and thus, advance our understanding on the complex mechanisms of coral symbiosis.

Plants acclimate to the changing environmental conditions by adjusting their molecular responses at different molecular levels including genome, epigenome, transcriptome, metabolome, and proteome levels to ensure survival. Plants adapt to abiotic stresses by establishing a ‘stress memory’ of previous exposures to mild stresses. Stress memory helps plants to develop tolerance and survive recurring exposures to the stress conditions. This memory establishes a new cellular state that differs from the state of unexposed naïve plants. This process is known as priming. Priming and the stress memory give the plants the possibility to acclimate to different biotic and abiotic stress conditions. The acquisition and maintenance of the stress-memory are two separate processes and crucial for successful tolerance to subsequent stress conditions. Priming promises to improve plant performance under severe stress conditions and enhance food production. Therefore, understanding the molecular basis of heat stress priming and stress-induced memory is of vital importance to plant biology. In this thesis, I investigated the role of transcriptional, post-transcriptional and metabolomic regulation controlling plant responses to heat stress, one of the major abiotic stresses affecting agriculture. I designed and established a heat stress priming strategy which reveals that heat stress-induced priming leads to the establishment of heat stress memory that permits plants to survive lethal temperatures. In this thesis, I analyzed the genome-wide differential gene expression, the alternative splicing patterns and regulation, and the reprogramming of the metabolic homeostasis that reprogram the establishment of the heat stress priming and stress-memory. I identified a set of candidate genes and metabolites playing key roles in the establishment of heat stress-induced memory. Intriguingly, it was possible also to establish a link between alternative splicing patterns and heat stress-induced memory. Subsequently, the knowledge of heat stress priming in Arabidopsis was translated into tomato crop plants, to improve their heat stress tolerance. This work enhances our understanding of the molecular basis of heat stress priming, and the establishment of heat stress memory, at transcriptional, post-transcriptional, and metabolomic levels. These findings can be translated into crop species to improve their survival under recurring heat stress conditions to improve world agriculture and food security.

<p>Carbohydrases have been used to improve fiber utilization in monogastric animals. However, their effects on animal performance and nutrient digestibility have been inconsistent in pigs. The efficacy of carbohydrases has been suggested to depend on enzyme activity and fiber composition, but recent evidence suggests other factors like environmental conditions may play significant role. The effect of heat stress (HS) on the efficacy of a multienzyme carbohydrase blend in growing pigs was investigated. It was hypothesized that HS alters the efficacy of carbohydrases. Ninety-six growing pigs (gilts:barrows; 1:1) (initial BW of 20.15±0.18 kg) were randomly assigned to 6 treatments, with 8 replicates of 2 pigs replicate pen in a 3×2 factorial arrangement: three levels of carbohydrase (0, 1X or 2X) and two room temperature conditions (20^oC constant or cyclical 28^oC night time and 35^oC daytime). The 1X is the recommended commercial dose of the enzyme (50g/tonne) and provides 1250 visco-units endo-β-1,4-xylanase, 4600 units α-L-arabinofuranosidase and 860 visco-units endo-1,3(4)-β-glucanase per kg of feed. The 2X dose was 100g/tonne. Pigs were fed ad libitum for 28 days and 1 pig per pen was sacrificed at d28. Heat stress increased the respiratory rate and skin temperature (P<0.001). There was no enzyme × temperature effect on response criteria. Enzyme treatment quadratically increased BW d28 (P=0.025), ADG (P=0.022) and average daily feed intake (ADFI) (P=0.032) with 1X being the highest. Heat stress reduced the BW at d14 (P=0.002) and d28 (P=0.006), average daily gain (ADG) (P=0.005) and ADFI (P<0.001). However, there was a trend of increased gain: feed ratio (G/F) (P=0.093) in the HS pigs compared to the thermoneutral (TN). Heat stress increased apparent jejunal digestibility (AJD) of energy (P=0.039) and apparent ileal digestibility (AID) of calcium (P=0.007). ADFI was positively correlated to ADG (r=0.57; P<0.001) but negatively correlated to G/F (r=-0.42; P=0.003). Enzyme supplementation increased in vitro viscosity at 3, 4 and 5 hours (P value). Heat stress reduced serum glucose concentration on d1 (P=0.0002) but increased serum non esterified fatty acid (NEFA) concentration (P=0.002). A similar trend to NEFA was observed in triacylglycride (TAG). In the jejunum, carbohydrases had trend for increased villi height (P=0.07) while HS reduced villi height (P=0.02). Heat stress increased the jejunal mRNA abundance of IL1β in the jejunum (P<0.001). There was a trend for a reduction in ileal MUC2 (P=0.092), occludin (P=0.091) due to HS, with the trend increasing in PEPT1 (P=0.064). There was no effect of HS on alpha diversity of fecal microbiome, but sampling day affected beta diversity. There was an increase in the abundance of pathogenic bacteria (like Clostridium) in the HS group. Heat stress did not alter the efficacy of carbohydrase but both carbohydrase and HS modulate pig performance independently.</p>

Soil salinity and heat stress are two major abiotic stresses affecting plant growth and yield. Transcription factors (TFs) are key regulators in stress responses. They link stress sensing with many tolerance mechanisms by translating stress signals into changes in gene expression that ultimately contribute to stress tolerance. The NAC (NAM, ATAF and CUC) TF family have been found to be involved in responses to biotic and abiotic stresses. In this PhD project, the role of NAC TFs in response to heat and salt stress was studied in the model system Arabidopsis thaliana (Arabidopsis), and in two agriculturally relevant species, Solanum lycopersicum (tomato) and Chenopodium quinoa (quinoa). Plants have the ability to acquire thermotolerance if they are pre-exposed to a mild, non-lethal high temperature. The maintenance of acquired thermotolerance for several days is known as thermomemory. Here we investigated the role of NAC TFs in thermotolerance. The expression profiles of 104 Arabidopsis NAC TFs were measured and compared between primed and unprimed plants. Some NACs with a distinctive expression pattern in response to thermopriming were selected for further phenotypic analysis. Knock-out (KO) mutants of the ATAF1 gene showed an enhanced thermomemory phenotype compared with wild type plants (WT) and from this work, the functions of the ATAF1 gene were studied further. RNAseq co-expression analyses of ATAF1 overexpressor and ataf1 KO plants found that ANAC055 expression was co-regulated with that of ATAF1. JUBGBRUNNEN1 (JUB1) is another NAC TF involved in responses to heat, drought and salinity. In this study, the role of AtJUB1 overexpression in salinity was investigated in tomato plants. AtJUB1 overexpression resulted in higher proline levels and improved maintenance of water content and biomass in AtJUB1-overexpressing plants grown hydroponically under salinity compared with WT plants. Quinoa has recently gained much attention because of its high nutritional value and high tolerance to several stresses including drought and salinity. NAC TFs are hypothesized to play a major role in quinoa’s tolerance to abiotic stresses. In this study, the NAC TFs family were identified and investigated in the genome of quinoa. 107 NAC TF genes were identified and their transcriptional responses to different stresses including salt, drought and heat were investigated.