维生素A和维生素D的免疫学研究进展

VA和VD是机体免疲功能的两种重要调节剂。本文主要论述了VA和VD时机体免疲反应的影响。VA对免疲系统发育、细胞免疫和体液免疲都产生影响。还可用于治疗疾病尤其是癌症。VD对细胞免疲影响较大，其活性代谢物1.25（OH）VD，可用于预防和治疗多种疾病，如癌症、血栓、结柱病、多发性硬化症、胰岛素依赖性糖尿病和类风湿性关节炎等多种自身性免疲性疾病。在押制器官移植排斥反应方面也有较大应用价值。     

饲粮中维生素对犊牛健康的影响

维生素在畜禽养殖过程中具有非常关键的作用,其中VA和VE对于畜禽具有促进免疫功能的作用,同时B族维生素对于畜禽疾病发生率的降低具有良好的作用。适当补充,可增强犊牛的生产性能和机体免疫能力。对犊牛养殖过程中VA、VE以及B族维生素对犊牛健康的作用与影响进行介绍,旨在为犊牛的科学养殖带来帮助。     

鸡大肠杆菌病的预防与治疗

正鸡大肠杆菌病是由致病性大肠杆菌所引起的一种传染病。其中包括大肠杆菌性腹膜炎、输卵管炎、脐炎、滑膜炎、气囊炎、肉芽肿、眼炎等多种疾病,对养鸡业危害较大。1原因1.1免疫抑制免疫抑制病破坏了机体正常的免疫功能。免疫既需要细胞免疫应答,也需要体液免疫应答。某些疾病会破坏鸡体正常的免疫功能,造成大肠杆菌的感染。1.2营养状况鸡群营养状况的好坏,很大程度上取决于营养是否充足。日粮营养水     

鱼类对维生素的利用及研究进展

维生素是维护鱼类健康、促进生长发育和调节生理功能所必需的一类低分子有机化合物。维生素的生理功能主要是调节体内的物质和能量代谢，参与氧化还原反应。下面主要介绍一些对鱼类健康生长有重要作用的维生素。 　　1. VA 　　VA对表皮和粘液层的完整性以及粘液的分泌很重要，可降低鱼体对一些传染性疾病的易感性，强化巨噬细胞的功能。以 2倍于生长需求量的 VA饲喂鲑鱼和斑点叉尾，可显著减少因白点虫寄生引起的死亡。 VA缺乏时，主要损害鱼类的眼和骨骼发育，例如鲤缺 VA时，体色苍白，生长缓慢，鳃和皮肤出血，鳃盖边缘皮膜反曲、…     

维生素E对鸡免疫功能的影响

维生素E是鸡体内不可缺少的一种脂溶性维生素,与鸡的免疫密切相关。它可以提高鸡细胞的抗氧化水平,维持膜结构的完整;可提高鸡的体液免疫水平;可提高鸡的细胞免疫,促进淋巴细胞的增殖反应;维生素E是通过减少前列腺素的生成而对免疫反应有促进作用的。影响维生素E对鸡免疫作用效果的因素较多。     

FK506结合蛋白51(FKBP51)的研究进展

FK506结合蛋白51(FKBP51)是一种具有多种结构域,多种生物学功能的免疫大分子,在机体免疫、类固醇激素的调节、癌症的发生和治疗以及抑郁症中发挥着重要作用,同时在畜禽研究中发现该基因是免疫性状的重要候选基因。文章对FKBP51基因的结构、分布及功能等方面进行了综述。     

MTT法检测淋巴细胞增殖能力的影响因素

<正>机体免疫系统中淋巴细胞增殖是机体对非己抗原刺激产生免疫应答过程中的重要事件。淋巴细胞增殖结果表现为产生效应淋巴细胞,清除非己抗原,维护机体内环境稳定。淋巴细胞增殖效果决定了效应淋巴细胞的数量,决定了机体免疫应答反应的强度,反映了机体的细胞免疫状态。因     

佐剂对DNA疫苗的影响

DNA疫苗是近年来发展较为迅速的一类生物制剂,它能诱导动物机体产生持久的体液免疫和细胞免疫,其在抗病毒、细菌和寄生虫的感染方面起到了重要作用。但与传统的灭活疫苗相比,其免疫效果并不理想。为了攻克DNA疫苗免疫效力低下的难题,一些学者已经研制了多种佐剂制品,以提高DNA疫苗对动物疾病免疫保护的能力。该文针对使用佐剂提高DNA疫苗免疫效力的最新概况做一综述。     

微量元素硒对动物免疫功能的影响

适量的硒能增强机体的免疫功能和对传染性疾病的抵抗力。本文概述了硒增强免疫功能的机制及硒与抗氧化、体液免疫、细胞免疫、免疫佐剂、抗病力的关系。     

鱼类维生素缺乏症状

鱼类对维生素缺乏的反应较慢,也就是说鱼类能较长时间在完全没有维生素摄入的情况下生存,一般饲养半个月后生长停止,3个月后体重下降,同时鱼类缺乏不同维生素时的表现症状也有所不同:1.缺VA:皮肤色浅、眼突出、鳍和皮肤出血、鳃盖变形。2.缺VD:生长下降。VD过剩时,鱼生长停滞、不活泼、体色发暗。3.缺VE:眼突出、肌营养不良、脊柱前凸、肾及胰脏退化;VE过剩时,生长停滞、对肝脏有毒。4.缺VK:凝血时间延长,伤口愈合慢;过剩时对鱼肝脏有毒,严重时会引起死亡。5.缺VB1:易惊吓、皮下出血、肤色浅。6.缺VB2:消瘦、怕光、易惊吓、皮肤及鳍…     

Establishing an upper level of intake for vitamin A in Atlantic salmon (Salmo salar L.) postsmolts

The vitamin A (VA) concentration in salmon aquaculture feeds is varying and may lead to sublethal adverse effects. In this study, 135 g Atlantic salmon postsmolts were given eight diets in duplicates with 6, 12, 26, 55, 82, 112, 360 and 749 mg retinol (ROL) kg⁻¹ for 116 days. Subsequently, fish given 6, 82 and 749 mg ROL kg⁻¹ were transferred to a common net pen and given a standard commercial diet for further 28 weeks. Feed conversion rate, liver functionality and markers of VA homoeostasis were not negatively affected by dietary VA level, but chronic high VA intakes led to adverse effects on growth and bone health. In plasma, there was an antagonistic effect of dietary ROL on circulating 1,25 (OH)₂ vitamin D₃ (calcitriol). Moreover, a dose–response of VA on craniofacial deformities, condition factor and vertebral morphometry and mechanical strength was observed. Vertebral deformities were observed after 28 weeks on a standard diet and not immediately after the 116 days on the experimental diet. Elevated VA is a risk factor for bone deformities, and the dietary intake of VA should not exceed 37 mg ROL kg⁻¹ body weight day⁻¹ in Atlantic salmon postsmolts.     

鱼类粘膜免疫研究进展

Fish immunology has achieved great progress in recent years. While before 1990s, most researches focused on the fish systematic immunity, and the mucosal immunity of fish had not been given enough attention. Indeed, it has been shown that fish mucosal immunity plays an important role in disease defense. Fish mucosal immunity research has made some exciting progress in this decade. This review will focus on such progress: Constitution of mucosal-associated tissues and distribution of different immune cells, including T/B lymphocytes, granules, monocytes, macrophages, goblet cells, etc, in these sites have been well described with the development of some monoclonal antibody to these cells and associated techniques. Non-specific immune response mechanism of mucosal tissues reported these years, such as secretion of non-specific anti-bacteria and anti-fungi substances in mucus, the respiratory burst, enzyme activity of immune cells and so on, is believed important for fish disease defense. The specific immunity of mucosal tissues also attracts much interest and makes great achievement in antigen presenting, MHC genes, antibody producing and antibody secreting cells, comparison of serum and mucus immunoglobulin, relationships of immune response between different mucosal immune tissues. Whether mucosal immune system is independent of systematic immune system is another interesting question and causes great concern. In recent years, some evidences from phyletic evolution and ontogenesis show that mucosal immunity is prior to systematic immunity in evolution. Dynamics of antibody producing of mucosal tissues and serum in immersion or oral vaccines immunized fish also shows immune response can be elicited in mucosal tissues independent of systematic immune system. Some researchers also begin to pay attention to factors involved in mucosal immune regulations, for instance, neuromodulators and cytokines. The level of these factors changes in fish immune response process but the mechanisms of regulation still remain unknown. Prospect of the promising future of fish mucosal immunity has also been discussed in this review.     

Effect of dietary vitamin A on Senegalese sole (Solea senegalensis) skeletogenesis and larval quality

The effects of different levels of vitamin A (VA) in Senegalese sole larval performance and development were evaluated by means of a dietary dose–response experiment using enriched Artemia metanauplii as a carrier of this micronutrient. Larvae were fed from 6 to 27 days post hatch (dph) with enriched Artemia containing graded levels of total VA (1.3, 2.1, 4.5 and 12.9 µg VA mg^− 1 DW). The content of VA in live prey directly affected its accumulation in larvae and early juveniles. Retinyl palmitate accumulated during larval ontogeny, whereas retinol showed the opposite trend, decreasing from hatching until 41 dph and then remaining constant until the end of the study.In metamorphic larvae (10 and 15 dph), VA did not affect the number of thyroid follicles or the intensity of the immunoreactive staining of T₃ and T₄. However, at older stages of development (post-metamorphic larvae: 20, 30, 41 and 48 dph), VA decreased the number of thyroid follicles but increased their mean size and enhanced T₃ and T₄ immunoreactive staining. A dietary excess of VA did not affect either larval performance in terms of growth and survival or the maturation of the digestive system. However, the most remarkable impact of this morphogenetic nutrient was detected during skeletal morphogenesis. Dietary VA accelerated the intramembranous ossification of vertebral centrums, which led to the formation of a supranumerary haemal vertebra and a high incidence of fused and compressed vertebrae in fish fed 2.1, 4.5 and 12.9 mg VA mg^− 1 DW. In addition, VA also affected those structures from vertebrae and caudal fin formed by chondral ossification, leading to defects in their shape and fusions with adjacent skeletal elements. In particular, the caudal fin was the region most affected by the dietary treatments. In order of importance, the bones with more developmental anomalies were the modified neural and haemal spines, epural, hypurals and parahypural. The impact of systemic factors such as thyroidal hormones in skeletogenesis should not be neglected since present results revealed that an excess of dietary VA affected the levels of T₃ and T₄, which might have affected bone formation and remodelling, leading to skeletal deformities.     

维生素D3对仿刺参幼参生长、体组成及 抗氧化能力的影响

为研究维生素D3对仿刺参(Apostichopus japonicus)幼参生长、体组成及抗氧化能力的影响,在基础饲料中分别添加0(D1)、250(D2)、500(D3)、1000(D4)、2000(D5)、3000(D6) IU/kg的维生素D3(实测值：95、334、570、1076、2063、3081 IU/kg),制作6组等氮等能的实验饲料,饲喂初始体重为(15.43±0.14) g仿刺参幼参56 d。结果显示,1) 维生素D3对仿刺参存活率(SR)无显著影响(P>0.05),显著提高了增重率(WGR)和特定生长率(SGR),D1组均显著低于其他组(P<0.05);D3、D4、D5组肠体比(IWR)显著高于其他3组(P<0.05),但3组之间差异不显著(P>0.05)。2) 维生素D3对体壁水分、粗蛋白和粗脂肪含量无显著影响(P>0.05);粗灰分含量随添加量的增加呈先升后降趋势,D5组达到最高值;羟脯氨酸含量呈先下降后上升趋势,D4组达到最低值;维生素D3显著提高了体壁Ca含量(P<0.05);体壁维生素D3的沉积量呈先上升后下降趋势,D4组达到最高值,显著高于其他组(P<0.05)。P含量呈先上升后平稳趋势;Mg含量呈上升趋势,D1组显著低于其他组(P<0.05);Fe含量呈先升后降趋势,D5、D6组显著低于其他组(P<0.05);Mn含量呈下降趋势,但各组间差异不显著(P>0.05)。3) 随着维生素D3添加量的增加,肠道碱性磷酸酶(AKP)及总超氧化物歧化酶(T-SOD)活力呈先上升后下降趋势,丙二醛(MDA)含量呈下降趋势,各组间总抗氧化能力(T-AOC)及过氧化氢酶(CAT)活力均无显著性差异(P>0.05)。研究表明,以增重率为评价指标,一元二次线性回归分析表明,初始体重为15.43 g的仿刺参对维生素D3的最适需求量为1587.5 IU/kg。     

Dietary effects of soybean products on gut microbiota and immunity of aquatic animals: A review

Soybean meal (SBM) is one of the most commonly used vegetable ingredient to replace fish meal in fish diets. However, SBM is limiting in some essential amino acids and contains numerous antinutritional factors and antigens that can affect intestinal microbiota and innate immune system in several finfish species and crustaceans and compromise health. The impact of SBM on health and gut microbiota of aquatic animals is not only affected by SBM in general, but also on the degree of treatment of the meal and exposure. Recently, many studies are actively seeking ways to complement or balance those adverse responses induced by high inclusion of SBM in aquaculture diets. These include advanced processing and mixture of feed with other feed components to balance antinutritional factors. The impact of dietary soybean oil on gut microbiota has also been investigated but to a lesser extent than SBM. As the gastrointestinal tract has been suggested as one of the major routes of infection in finfish species and crustaceans, the effect of soybean products on the gut microbiota is important to investigate. Several studies have focus on supplementation of SBM on the adverse responses of the innate immune system as immunological mechanisms are likely involved in the underlying pathology. However, the precise cause of the inflammatory process has not yet been clarified, even though some investigations have suggested that alcohol‐soluble antinutritional factors, especially soy saponins, are potential causative factors. Possible interactions between soybean products and innate immune system in several finfish species and crustaceans are discussed.     

Skeletal and Pigmentation Defects following Retinoic Acid Exposure in Larval Summer Flounder, Paralichthys dentatus

Supplementation of larval diets with vitamin A (VA) is routinely and successfully used to stimulate pigmentation development in hatchery‐reared flatfishes. However, excess dietary VA can lead to high levels of its metabolite retinoic acid (RA) and has been associated with the occurrence of skeletal deformities, presumably via RA toxicity. We reared summer flounder larvae, Paralichthys dentatus, in water containing 0‐ to 20‐nM RA to assess its effects on postmetamorphic pigmentation and on skeletal development. RA exposure disrupted pigmentation development: treated tanks had a smaller percentage of normally pigmented fish than did controls, with increased numbers of both hypo‐ and hyperpigmented individuals. Exposure also affected the development of several skeletal features: RA treatment correlated with a significant increase in the severity of defects in jaws, fins, hypurals, and vertebrae compared with control groups.     

In vivo calcitropic effect of some vitamin D compounds in the marine Antarctic teleost,Pagothenia bernacchii

The Antarctic notothenioid, Pagothenia bernacchii, were found to have plasma total and free calcium levels, plasma inorganic phosphate and whole body calcium efflux rates which were similar to those seen in other teleosts. But total bone calcium was lower than reported for other teleosts. A single injection of vitamin D₃ (5 ng g^–1 fish) increased plasma total and plasma free calcium and these increases were associated with an increase in whole body calcium efflux and bone calcification. Conversely, the same treatment with 1,25-(OH)₂-D₃ reduced plasma free calcium. This seco-steroid also increased the specific activity of ⁴⁵Ca in bone at 40h post-injection but did not significantly effect total bone calcium, plasma total calcium or whole body calcium efflux. 25-OH-D₃ at the same dose had no effect on any of the parameters tested and none of the seco-steroids tested had any effect on plasma total inorganic phosphate. These data show that both D₃ and 1,25-(OH)₃-D₃ can have calcitropic effects in this marine teleost and that these two forms of vitamin D can exert different effects within the same species.     

Development and use of an Arctic charr cell line to study antiviral responses at extremely low temperatures

Arctic charr (Salvelinus alpinus) are the northernmost distributed freshwater fish and can grow at water temperatures as low as 0.2 °C. Other teleost species have impaired immune function at temperatures that Arctic charr thrive in, and thus, charr may maintain immune function at these temperatures. In this study, a fibroblastic cell line, named ACBA, derived from the bulbus arteriosus (BA) of Arctic charr was developed for use in immune studies at various temperatures. ACBA has undergone more than forty passages at 18 °C over 3 years, while showing no signs of senescence‐associated β‐galactosidase activity and producing nitric oxide. Remarkably, ACBA cells survived and maintained some mitotic activity even at 1 °C for over 3 months. At these low temperatures, ACBA also continued to produce MH class I proteins. After challenge with poly I:C, only antiviral Mx proteins were induced while MH proteins remained constant. When exposed to live viruses, ACBA was shown to permit viral infection and replication of IPNV, VHSV IVa and CSV at 14 °C. Yet at the preferred temperature of 4 °C, only VHSV IVa was shown to replicate within ACBA. This study provides evidence that Arctic charr cells can maintain immune function while also resisting infection with intracellular pathogens at low temperatures.     

The effects on some non‐enzymatic antioxidants and oxidative stress of Astacus leptodactylus (Esch., 1823) of starvation periods

This study investigated the effect of starvation (78 days) and refeeding (33 days) on the oxidative stress [malondialdehyde (MDA)] and the non‐enzymatic antioxidants [vitamin E (VE), vitamin C (VC), vitamin A (VA), beta carotene (βC) and reduced glutathione (GSH)] in the hepatopancreas, muscle and gill tissues of freshwater crayfish (Astacus leptodactylus). Crayfish were divided into three experimental groups: control (fed), starved (not fed) crayfish for 78 days and refeeding crayfish for 33 days after 78 days of starvation. The biochemical analysis of the tissues was conducted at 3, 18, 33, 48, 63 and 78 days of starvation and feeding and at 3, 18 and 33 days of refeeding. It was determined that crayfish can withstand starvation period of 78 days. In all of the periods, the MDA levels were significantly higher in the tissues of starved crayfish when compared with the control. The findings of this study demonstrate that starvation has a negative effect on the VE, VC, VA, βC and GSH levels in the crayfish. The measured parameters returned to control values after 33 days of the refeeding. Additionally, the starvation resulted in decreased levels of VE, VA and βC in the abdomen muscle of crayfish consumed by humans.     

Characterization of the isoforms of type IIb sodium-dependent phosphate cotransporter (Slc34a2) in yellow catfish, <Emphasis Type="Italic">Pelteobagrus fulvidraco</Emphasis>, and their vitamin D<Subscript>3</Subscript>-regulated expression under low-phosphate conditions

In this study, two isoforms slc34a2 genes (type IIb sodium-dependent phosphate cotransporter), slc34a2a2 and slc34a2b, were cloned from intestine and kidney of yellow catfish (Pelteobagrus fulvidraco), with rapid amplification of cDNA ends. The structure differences and the regulation effects of dietary VD₃ under low phosphorus were compared among three isoforms of slc34a2 in yellow catfish. The predicted Slc34a2a2 and Slc34a2b proteins match 65 % and 53.8 % sequence identity, with Slc34a2a1, respectively. The membrane-spanning domains were different among these three isoforms. Intestinal Slc34a2a1 and Slc34a2a2 proteins had eight and eleven transmembrane domains, while renal Slc34a2b protein had nine. The tissue distribution study showed that same as slc34a2a1, slc34a2a2 mRNA was mainly distributed in intestine and slc34a2b mRNA in kidney. The effect of vitamin D₃ (VD₃) level on slc34a2 subfamily expression under low-phosphate conditions, induced by the addition of 0 (VD0), 324 (VD1), 1243 (VD2), 3621 (VD3), 8040 (VD4), or 22700 (VD5) IU VD₃/kg feed, was assessed by qPCR. The dose-responsive expression of intestinal slc34a2a2 and high expression of intestinal slc34a2a2 in VD5 together with peak expression of kidney slc34a2b in VD3 coincided with the accumulation of body phosphate content. These data suggested that appropriate level of dietary VD₃ up-regulated slc34a2a1, slc34a2a2, and slc34a2b mRNA levels, which increased phosphate retention. In conclusion, the current study provided another possible approach to improve dietary phosphate utilization by adding appropriate level of VD₃ to a low-phosphate diet to regulate intestinal and renal slc34a2 gene expression and thus minimize the excretion of phosphorus in yellow catfish.