An immunologist's perspective on nutrition,immunity, and infectious diseases: Introduction and overview

The immune system is a multifaceted arrangement of membranes (skin, epithelial, and mucus), cells, and molecules whose function is to eradicate invading pathogens or cancer cells from a host. Working together, the various components of the immune system perform a balancing act of being lethal enough to kill pathogens or cancer cells yet specific so as not to cause extensive damage to “self” tissues of the host. A functional immune system is a requirement of a healthy life in modern animal production. Yet infectious diseases still represent a serious drain on the economics (reduced production, cost of therapeutics, and vaccines) and welfare of animal agriculture. The interaction involving nutrition and immunity and how the host deals with infectious agents is a strategic determinant in animal health. Almost all nutrients in the diet play a fundamental role in sustaining an optimal immune response, such that deficient and excessive intakes can have negative consequences on immune status and susceptibility to a variety of pathogens. Dietary components can regulate physiological functions of the body; interacting with the immune response is one of the most important functions of nutrients. The pertinent question to be asked and answered in the current era of poultry production is whether the level of nutrients that maximizes production in commercial diets is sufficient to maintain competence of immune status and disease resistance. This question, and how to answer it, is the basis of this overview. Clearly, a better understanding of the interactions between the immune signaling pathways and productivity signaling could provide the basis for the formulation of diets that optimize disease resistance. By understanding the mechanisms of nutritional effects on the immune system, we can study the specific interactions that occur between diet and infections. This mechanism-based framework allows for experiments to be interpreted based on immune function during an infection. Thus, these experiments would provide a “real world” assessment of nutritional modulation of immune protection separating immune changes that have little impact on resistance from those that are truly important. Therefore, a coordinated account of the temporal changes in metabolism and associated gene expression and production of downstream immune molecules during an immune response and how nutrition changes these responses should be the focus of future studies. These studies could be answered using new “-eomics” technologies to describe both the local immune environments and the host-pathogen interface.     

Influence of several non‐nutrient additives on nonspecific immunity and growth of juvenile turbot,Scophthalmus maximus L.

The effects of three non‐nutrient additives on nonspecific immunity and growth of juvenile turbot (Scophthalmus maximus L.) were studied in this feeding experiment. The five treatments are basal diet alone, basal diets containing three different additives [0.4 g kg^?1 of xylo‐oligosaccharides (XOS), 1.3 g kg ^?1 of yeast cell wall and 0.8 g kg ^?1 of bile acids] individually or in combination. Two hundred and twenty‐five turbots (average initial weight 151.3 ± 11.3 g) were randomly allotted in five treatments with three replicates within each treatment in a 72‐day period. Comparing with basal diet group, activities of C3, C4, phagocyte, lysozyme, specific growth rate and feed conversion rate in yeast cell wall, XOS and the combined groups was enhanced significantly (P < 0.05); however, these parameters in bile acid groups were increased slightly (P > 0.05) except for phagocyte (P < 0.05); superoxide dismutase activity in additive groups was not significantly increased (P > 0.05) except for the combined group (P < 0.05). In conclusion, supplementation of yeast cell wall and XOS enhanced the nonspecific immunity of juvenile turbot. Synergistic or additive effect of the three additives was not observed.     

复合酶对肉仔鸡生产性能及代谢的影响

选取１日龄ＡＡ肉仔鸡８０只，随机分成二组，研究日粮添加和不添加复合酶对肉仔鸡生产性能、代谢及免疫的影响。结果表明：复合酶使肉仔鸡日增重提高７％～７．７％，料肉比降低了４．５％～４．９％，但采食量增加不显著；血液中尿酸和血糖浓度显著下降，血浆胰岛素与血清Ｔ３浓度显著提高，提示复合酶改善了肉仔鸡营养物质的吸收与代谢；此外，血清蛋白和血浆ＩｇＧ水平高于对照组，表明复合酶促进了免疫功能     

Streptococcus Suis: Past and Present

Staats, J.J., Feder, I., Okwumabua, O. and Chengappa, M.M., 1997. Streptococcus suis: past and present. Veterinary Research Communications, 21 (6), 381-407Steptococcus suis is a Gram-positive, facultatively anaerobic coccus that has been implicated as the cause of a wide range of clinical disease syndromes in swine and other domestic animals. In swine, the disease has spread worldwide but is more prevalent in countries with intensive swine management practices. The disease syndromes caused by S. suis in swine include arthritis, meningitis, pneumonia, septicaemia, endocarditis, polyserositis, abortions and abscesses. S. suis has also been implicated in disease in humans, especially among abattoir workers and swine and pork handlers. In humans, S. suis type 2 can cause meningitis, which may result in permanent hearing loss, septicaemia, endocarditis and death. The pathogenic mechanism of S. suis is not well defined. Several virulence factors have been identified, but their roles in pathogenesis and disease have not been well elucidated. Much work is in progress on characterization of virulence factors and mechanisms, with emphasis on the control of the disease. Because of the non-availability of suitable immunoprophylaxis, control of S. suis infection has depended mainly on the use of antimicrobials.     

黄芪对史氏鲟抗氧化能力及免疫力的影响

采用灌服的方法研究了黄芪Astragalus m em branaceus水煎剂对1 龄史氏鲟Acipenser schrencki部分非特异性免疫指标和抗氧化能力的影响。试验分3组进行,每组放史氏鲟10尾,每日灌服1次黄芪水煎剂,剂量均按每100 g鱼体重灌服0.3 mL药液,相当于黄芪(干物质)的用量为日投喂饲料重量的0.5%(A组)、1.0%(B组)和2.0%(C组),对照组鱼灌服蒸馏水。结果显示:A组和B组的史氏鲟被灌服黄芪水煎剂后,血浆及各组织中的溶菌酶含量呈升高的趋势,C组鱼的不同组织变化不一,但均无统计学意义;史氏鲟血浆中的一氧化氮(NO)及一氧化氮合酶(NOS)无显著变化,但B组和C组史氏鲟肝脏中的NO含量与对照组有显著差异(P<0.05),C组史氏鲟肝脏中的NOS活性也与对照组有显著差异(P<0.05);对史氏鲟血浆及肝脏中超氧化物岐化酶(SOD)的活性有增强作用,尤其B组鱼的SOD酶活性较对照组显著升高;黄芪能显著降低史氏鲟血浆中丙二醛(MDA)的含量,提高史氏鲟的抗氧化能力。     

长期低铅暴露对小鼠细胞免疫功能的影响

目的：观察长期低铅暴露对小鼠细胞免疫功能的影响。方法：将120只幼年小鼠分成6组，分别给予含有不同剂量的铅饲料8周．观察分析铅暴露后小鼠T细胞亚群CD4^ 、CD8^ 的分布、血清TNF-α含量，并测定小鼠脾脏系数。结果：各组血铅随铅的暴露剂量升高而升高；T细胞亚群分布异常、CD4^ 减少与CD4^ ／CD8^ 降低，并随各组血铅浓度的升高而减少；各组脾脏系数与对照组比较差异均有显著性。结论：长期铅暴露可使细胞免疫功能和免疫器官的结构受损。     

熊胆茶对实验性肝损伤动物保护作用的研究

研究了熊胆茶的肝保护作用及其抗炎免疫作用。结果显示：熊胆茶对四氯化碳(CCl4)和D-半乳糖胺(D-Galn)致小鼠的肝损伤有明显的保护作用，可使血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)、血清总胆固醇(T-CHO)、丙二醛(MDA)的含量明显降低，使肝脏中糖原(CHO)的含量明显升高，且具有一定的抗炎和提高免疫功能的作用。     

团头鲂细菌性败血症免疫研究

将温和气单胞菌(Aeromonas sobria)复壮，在28℃条件下加福尔马林灭活48h，制备成灭活苗。用该疫苗免疫团头鲂，取免疫后第10d，20d，30d的血清做凝集抗体试验，最高凝集抗体效价达1：32～128，对照组为1：4～8；免疫鱼的抗感染保护力达70％。     

大鼠脊髓P物质对细胞免疫调节作用的研究

目的：观察大鼠脊髓Ｐ物质对细胞免疫水平的影响，方法：两组新生大鼠分别皮下注射辣椒素（ＣＡＰ）和Ｐ物质抗血清，成年大鼠则于脊髓蛛网膜下腔注射，用丝裂原激活的大鼠脾细胞方法测定了淋巴细胞的白细胞介素－２（ＩＬ－２）水平。结果：大鼠皮下及脊髓蛛网膜下腔各分别注射ＣＡＰ，Ｐ物质抗血清后，ＩＬ－２的水平较对照组显著升高（Ｐ〈０．０１）。结论：新生大鼠（皮下）与成年大鼠（蛛网膜下腔）注射ＣＡＰ或Ｐ物质抗血清垃