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酵母细胞壁对肠道菌群的促进作用
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时间：2019-10-31动物集约化生产是一个极具挑战性的环境，因此，增强动物的免疫系统和维持肠道菌群健康可能是提高生产力的关键因素之一；酵母细胞壁在这一过程中起着重要的作用。
给2d肉鸡添加酿酒酵母细胞壁（0.5kg/MT，酿酒酵母是来自甘蔗生产乙醇发酵的过程中，包含35%左右β-葡聚糖（1，3和1，6）和20% 甘露寡糖（MOS）），通过口服肠炎沙门氏菌（SE）感染。试验包含空白对照组（无任何处理）、酵母细胞壁组（未感染SE）、感染SE组（未添加酵母细胞壁）和酵母细胞壁感染组（添加酵母细胞壁+感染SE）。通过采集鸡只血液进行细胞定量分析。
数据显示，酵母细胞壁感染组鸡只，在感染后2d和6d时，肉鸡血液中的标记物减少了，这表明肠道的完整性和通透性显著提高；因为SE可以通过菌毛粘附到粘膜上，进而产生毒素，导致紧密连接和肠上皮细胞的损害，入侵并进入血流和其他内部器官和组织。
与感染SE组和空白对照组比较，酵母细胞壁感染组肉鸡在14d时，从血液到肠道的白细胞移动减少；当免疫系统再细分时，分析不同的细胞显示了更多的抗原呈递细胞（APC）、抑制单核细胞、辅助T淋巴细胞（CD4，分泌白细胞介素和刺激可以攻击抗原的细胞增殖）。酵母细胞壁组肉鸡对于以上细胞的分析，以及细胞毒性T淋巴细胞（CD8）呈现出一种中间值（介于感染组和空白对照组之间）。
在14d时，酵母细胞壁感染组鸡只的抗沙门氏菌IgA产生量最多，这表明免疫系统的特异性反应更快更强，消耗更少的能量和营养，因为炎症反应过程似乎减短了。
因此，酵母细胞壁添加可以帮助肉鸡实现更早和更快的先天免疫激活和反应，减少/最小化病原体导致的损害以及造成的性能损失。这种反应对处于发育和繁殖早期阶段，或应激和环境挑战时期的动物尤为重要，它可以预防和增强动物的抵抗力，从而最大限度地减少进一步的损害。
Boosting intestinal microbiota with the yeast cell wall
For a few years, we have been receiving advice from international health organisations about the use of antibiotics in the animal production industry. The World Health Organization (WHO) warned that a lack of effective antibiotics was as serious a threat to security as a deadly disease outbreak. We should focus our attention on a set of measures which promote safe animal growth and mainly act in the prevention of diseases.
The role of intestinal microbiota
Many studies prove that beyond antibiotics’ immediate impact on microbiota, these types of medicines also affect the genetic expression, protein activity, and general metabolism of intestinal microbiota. As well as increasing the immediate risk of infection, the microbial changes caused also have long terms effects on the basic immune system.
Animals’ intestinal microbiota plays an important role in regulating their immune systems, since it not only modulates various physiological, nutritional, metabolic and disease-fighting processes, but can also alter the physiopathology of illnesses, conferring resistance, or promote enteric parasitical infections. Natural intestinal bacteria act as molecular adjuvants which provide indirect immunostimulation, helping the organism defend itself against infections.
Immune system – first line of defence
Broilers have a large quantity of lymphoid tissue and immune system cells in their intestinal mucosa, called the GALT (gut-associated lymphoid tissue), which in turn constitutes the MALT (mucosa-associated lymphoid tissue). The GALT is constantly exposed to food antigens, microbiota, and pathogens, and needs to identify components which are present in the intestinal lumen and which could present a possible threat to the animal. The immune system’s first line of defence is composed of phagocytic cells (macrophages, heterophiles, dendritic cells and natural killer cells), which have Toll-type receptors on their surface. These receptors recognise microbial standards and induce an immediate innate immune response. After this activation and phagocytosis, the phagocyte (antigen-presenting cell – “APC”) presents a processed fragment of the antigen and a chain reaction is initiated against it. The innate immune system’s recognition of pathogens first triggers immediate innate defences and, subsequently, the activation of the adaptive immune response.
It is important to emphasise that this series of responses of the innate immune system requires several nutrients, especially metabolic energy, since it is a nonspecific and pro-inflammatory response, but necessary to control the proliferation, invasion, and damage caused by the antigen in the animal organism. However, a prolonged pro-inflammatory response may lead to secondary diseases, immunosuppression, maintenance of immune homeostasis, intestinal dysbiosis, and finally, decline in performance and mortality.
Decreasing the occurrence of immunosuppression
A correct program of measures, including balanced nutrition, vaccination, reduction of stress factors, good management and animal well-being practices, can considerably decrease the occurrence of immunosuppression. Adding dietary additives, which act in the modulation of the innate immune system and microbiota, improves the defence response against potential challenges.
The yeast cell wall Saccharomyces cerevisiae (ImmunoWall, ICC Brazil) is derived from the process of sugar cane fermentation in ethanol production, and is made up of around 35% β-glucans (1,3 and 1,6) and 20% Mannan-Oligosaccharides (MOS). β-glucans are recognised for their phagocytic cells, encouraging them to produce cytokines which will initiate a chain reaction to induce immunomodulation and enhance the responsiveness of the innate immune system. On the other hand, MOS are able to agglutinate type-1 fimbriae pathogens and various strains of Salmonella and Escherichia coli.
文章来源：猪营养国际论坛
【免责声明】：文章来源于网络，我们对文中陈述观点判断保持中立，并不对文章观点负责。仅供读者参考。版权属于原作者。
The role of intestinal microbiota
Many studies prove that beyond antibiotics’ immediate impact on microbiota, these types of medicines also affect the genetic expression, protein activity, and general metabolism of intestinal microbiota. As well as increasing the immediate risk of infection, the microbial changes caused also have long terms effects on the basic immune system.
Animals’ intestinal microbiota plays an important role in regulating their immune systems, since it not only modulates various physiological, nutritional, metabolic and disease-fighting processes, but can also alter the physiopathology of illnesses, conferring resistance, or promote enteric parasitical infections. Natural intestinal bacteria act as molecular adjuvants which provide indirect immunostimulation, helping the organism defend itself against infections.
Broilers have a large quantity of lymphoid tissue and immune system cells in their intestinal mucosa, called the GALT (gut-associated lymphoid tissue), which in turn constitutes the MALT (mucosa-associated lymphoid tissue). The GALT is constantly exposed to food antigens, microbiota, and pathogens, and needs to identify components which are present in the intestinal lumen and which could present a possible threat to the animal. The immune system’s first line of defence is composed of phagocytic cells (macrophages, heterophiles, dendritic cells and natural killer cells), which have Toll-type receptors on their surface. These receptors recognise microbial standards and induce an immediate innate immune response. After this activation and phagocytosis, the phagocyte (antigen-presenting cell – “APC”) presents a processed fragment of the antigen and a chain reaction is initiated against it. The innate immune system’s recognition of pathogens first triggers immediate innate defences and, subsequently, the activation of the adaptive immune response.
It is important to emphasise that this series of responses of the innate immune system requires several nutrients, especially metabolic energy, since it is a nonspecific and pro-inflammatory response, but necessary to control the proliferation, invasion, and damage caused by the antigen in the animal organism. However, a prolonged pro-inflammatory response may lead to secondary diseases, immunosuppression, maintenance of immune homeostasis, intestinal dysbiosis, and finally, decline in performance and mortality.
A correct program of measures, including balanced nutrition, vaccination, reduction of stress factors, good management and animal well-being practices, can considerably decrease the occurrence of immunosuppression. Adding dietary additives, which act in the modulation of the innate immune system and microbiota, improves the defence response against potential challenges.
The yeast cell wall Saccharomyces cerevisiae (ImmunoWall, ICC Brazil) is derived from the process of sugar cane fermentation in ethanol production, and is made up of around 35% β-glucans (1,3 and 1,6) and 20% Mannan-Oligosaccharides (MOS). β-glucans are recognised for their phagocytic cells, encouraging them to produce cytokines which will initiate a chain reaction to induce immunomodulation and enhance the responsiveness of the innate immune system. On the other hand, MOS are able to agglutinate type-1 fimbriae pathogens and various strains of Salmonella and Escherichia coli.
Improved intestinal integrity
A recent study conducted by Beir?o et al. (2018), in which broilers received ImmunoWall supplements (0.5 kg/MT) and were infected with Salmonella Enteritidis [SE] (via an oral dosage of 108 CFU per broiler) at two days of age, showed that from four to eight days of age (two and six days post-infection, respectively), the yeast cell wall product reduced the passage of the marker (Dextran-FITC, 3-5 kD) into the challenged broilers’ blood stream. These results show a significant improvement in intestinal integrity and permeability, since SE is a bacterium capable of sticking to the mucosa through its fimbriae, producing toxins and causing damage to tight junctions and enterocytes, invading them and translocating them into the blood stream and other internal organs and tissues .
文章来源：猪营养国际论坛
【免责声明】：文章来源于网络，我们对文中陈述观点判断保持中立，并不对文章观点负责。仅供读者参考。版权属于原作者。
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