Effect of different stressors on milk production of Saanen goats and their relationship with oxidative stress in the mammary gland

A exploração da Caprinocultura vem crescendo e sendo considerada uma opção rentável, principalmente para exploração leiteira, pois o leite de cabra é considerado um alimento de alto valor nutritivo e indicado nos casos em que indivíduos possuem problemas digestivos ou intolerância ao leite de vaca. A melhoria na qualidade do leite, manutenção e aumento da produção leiteira são os principais elementos deste agronegócio. Em geral, as cabras são descritas como robustas em comparação com outras espécies de gado em condições adversas do meio ambiente e manejo. No entanto, o estresse altera sua homeostase com consequências negativas na produção de leite. Por outro lado, a maioria dos estudos relacionados ao estresse em zootecnia é realizado apenas com um estressor, e esses estudos não consideram que o estresse pode ser cumulativo e agravar as perdas produtivas. Por essas razões, o presente estudo analisou os efeitos do estresse agudo cumulativo causado por diferentes estressores na produção de leite, na qualidade do leite e sua influência na expressão de células epiteliais mamárias em 30 cabras Saanen em final de lactação. Os animais foram expostos a diferentes estressores ambientais e de manejo ou mantidos em condições de conforto (grupo controle). Os estressores foram estresse por calor, administração de hormônio adrenocorticotrófico (ACTH), cuidados com os cascos e chuva durante quatro dias consecutivos em dezembro de 2018 e fevereiro de 2019. Embora, as cabras submetidas aos diferentes estressores foram capazes de restabelecer a homeostase, a exposição aos desafios ambientais e de manejo (calor, ACTH, cuidado do casco e chuva) diminuíram a produção de leite das cabras, demonstrando um efeito cumulativo dos estressores agudos. De fato, houve efeitos significativos dos estressores na frequência respiratória, temperatura retal, cortisol, insulina, triiodotironina e nas concentrações de fator de crescimento semelhante à insulina 1 das cabras (P ≤ 0,005) em comparação com o observado no grupo controle. Houve efeito significativo do estresse sobre a glicose, ureia, triglicerídeos, colesterol, lipoproteína de alta densidade e lipoproteína de baixa densidade. Os estressores também aumentaram significativamente a expressão dos genes GR, CAT, SOD e IFN-γ no tecido mamário das cabras Saanen. Por essas razões, os estressores resultaram em um aumento da contagem de células somáticas (CCS) no leite e uma diminuição na produção de leite em comparação às cabras controle. Nesse contexto, os resultados deste estudo indicam que os produtores devem evitar os efeitos cumulativos dos estressores agudos, pois eles têm um impacto negativo na produção de leite.Goat husbandry is considered a profitable option to farmers mainly for dairy, in fact goat\'s milk have a high nutritional value and is indicated when people have digestive problems or intolerance to cow\'s milk. However, the improvement of production and quality of milk are the main goal of this agribusiness. In general, goats are described to be more robust compared to other livestock species to adverse environmental conditions and management. However, the stress changes its homeostasis having negative consequences on milk production. By other way, most of studies related to stress in animal science are performed with just a stressor, and these studies not considering that stress may be cumulative and aggravate productive losses. For these reasons, the present study analyzed the effects of cumulative acute stress caused by different stressors on milk yield, milk quality and its influence on the expression of mammary epithelial cells in in 30 Saanen goats at the end of lactation. The animals were exposed to different environmental and management stressors or maintained under conditions of comfort (control group). The stressors were heat stress, adrenocorticotropic hormone (ACTH) administration, hoof care and rain during four consecutive days in December 2018 and February 2019. Although, goats subjected to different stressors were able to restore homeostasis, the exposure of goats to environmental and management challenges (heat stress, ACTH, hoof care, and rain) decreased the milk yield of Saanen goats, demonstrating a cumulative effect of the acute stressors. In fact, there were significant effects of the stressors on respiratory rate, rectal temperature, cortisol, insulin, triiodothyronine and insulin-like growth factor 1 concentrations of the goats (P ≤ 0.05) compared with that observed in control group. There was a significant stress effect on glucose, urea, triglycerides, cholesterol, high-density lipoprotein and low-density lipoprotein. The stressors also significantly increased the expression of GR, CAT, SOD and IFN-γ genes in the mammary tissue of Saanen goats. For these reasons, the stressors resulted in an increase of somatic cell count (SCC) in milk and a decrease of milk yield in comparison to the control goats. In this context, the results of this study indicate that farmers should avoid the cumulative effects of acute stressors because they have a significant negative impact on milk production

Effect of Acute and Cumulative Stress on Gene Expression in Mammary Tissue and Their Interactions with Physiological Responses and Milk Yield in Saanen Goats

This study addresses the hypothesis that different acute stressors can cumulatively decrease milk yield. In fact, in a time of global warming, the impact of environmental stress and farm management practices on milk production remains unclear. In this context, our objective was to investigate the effect of acute and cumulative stress on gene expression in mammary tissue and their interactions with physiological responses and milk yield in Saanen goats. Thirty lactating goats were subjected to two treatments: (1) control (CT), in which goats were maintained following a habitual routine under comfort conditions; (2) stress (ST), in which the goats were subjected to different types of environmental stress: heat stress, adrenocorticotropic hormone administration, hoof care management, and exposure to rain. These stressors were performed sequentially, with one stress per day on four consecutive lactation days, to evaluate their effect on milk quality and milk yield. Our results showed that compared to CT goats, cumulative stress increased the gene expression of glucocorticoid receptor (GR), interferon-gamma (IFN-γ), superoxide dismutase (SOD), and catalase (CAT) in mammary tissue, which are indicators of cortisol action, inflammatory response, and antioxidant enzymes. Furthermore, the acute challenges imposed on ST goats changed their rectal temperature and respiratory frequency and increased cortisol, glucose, cholesterol, triglycerides, and high-density lipoprotein release in plasma when compared to CT goats. Although these physiological and metabolic responses restore homeostasis, ST goats showed lower milk yield and higher somatic cell count in milk than CT goats. In conclusion, the results confirmed our initial hypothesis that different acute stressors cumulatively decrease the milk yield in Saanen goats

Effect of Different Immersion Tank Water Temperatures on the Microbiological Quality of Rabbit Carcasses

The pre-chilling of rabbit carcasses in an immersion tank directly interferes with microbial control. Therefore, this study was developed to examine the influence of different pre-chill tank water temperatures (4, 7, and 10 °C) on the microbiological quality of rabbit carcasses. Samples of rabbit carcasses and water and ice from the pre-chiller tank were collected; mesophilic aerobic heterotrophic microorganisms (MES), enterobacteria (EC), and coagulase-positive Staphylococcus (CPS) were counted; and the presence of Salmonella spp. was investigated. After the carcasses were immersed in the pre-chiller, there was a significant increase (p −1 at 4 and 10 °C, respectively) and EC (3.20, 4.15, and 4.84 Log CFU·mL−1 at 4, 7, and 10 °C, respectively). The average EC count tended to increase after the carcasses were immersed in the pre-chiller at different temperatures, but this increase was not significant. Water samples showed MES, EC, and CPS counts only after the immersion of the carcasses; however, the presence of these microorganisms was not detected in any of the ice samples. Salmonella spp. was not identified in the analyzed samples. The microorganisms analyzed at the three pre-chiller water temperatures evaluated did not multiply on the surface of the rabbit carcasses or in the pre-chiller water after carcass immersion. This study showed that none of the three pre-chilling temperatures were able to reduce the count of indicator microorganisms in the carcasses of rabbits. These data provide scientific support to discuss the need for specific norms and guidelines for rabbit meat production

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora