精氨酸对猪免疫功能影响的研究进展

精氨酸是一种动物机体必需的营养素。研究发现,精氨酸是动物体内一种重要的功能性氨基酸,不仅在细胞分裂、伤口复原、蛋白质合成和分泌激素等生理过程起着重要的作用,同时作为一种重要的免疫调节剂参与体内的免疫调节。本文就精氨酸的理化性质、来源和分解代谢及其在猪免疫方面的研究进展进行了综述。     

外源性谷氨酰胺对肉仔鸡空肠形态结构的影响

谷氨酰胺(Gln)作为机体一种重要的能量和原料来源，是一些快速分裂细胞的主要能量来源，也可以向其他重要的氨基酸及某些生物大分子进行转化，并且可以抵抗外来的毒害作用，特别在维持肠道和免疫系统的正常形态和功能方面有着重要的作用。目前，国内外关于Gln在畜禽生产中的研究主要是在断奶仔猪方面，     

我国猪源和鸡源大肠杆菌抗生素耐药性相关基因研究进展

大肠杆菌作为一种条件致病菌和重要的耐药性指示菌,国内外已有大量猪源、鸡源大肠杆菌耐药性相关基因的研究报道.受动物种属、地域等来源性差异,以及耐药机制、亚型等因素的影响,研究中涉及很多种不同的耐药性相关基因,且检出率也不尽相同.根据耐受抗菌药物种类,对这些基因作用机理及分布情况等方面综述,以期为研究大肠杆菌耐药性产生机制...     

γ-氨基丁酸的代谢及其在鱼类养殖中的应用研究进展

氨基丁酸是一种广泛存在于动植物体及微生物体内的条件性必需营养素。GABA作为一种重要的抑制性神经递质,在机体内的许多新陈代谢活动中发挥着重要作用。近年来,γ-氨基丁酸作为饲料添加剂已逐步应用于鱼类养殖生产中,在鱼类的生长、食欲及抗应激等方面发挥重要作用。本文主要综述了γ-氨基丁酸理化特性、来源、分布、代谢以及γ-氨基丁酸对鱼类的促生长、抗氧化及免疫等方面作用,为γ-氨基丁酸在鱼类养殖中的合理应用提供参考。     

河鲀营养研究进展及展望

本文以红鳍东方鲀(Takifugu rubripes)和暗纹东方鲀(Takifugu obscurus)为例,综合了国内外关于河鲀主要营养物质需要量、需求特点的研究进展,从河鲀对蛋白质和氨基酸、脂肪和脂肪酸、碳水化合物、维生素、矿物质以及其他营养物质的需要量或需求特点展开综述,并对下一步相关研究提出展望,以期为河鲀的营养需求及河鲀专用配合饲料的研究开发提供依据和参考。     

多糖的研究

1前言多糖与免疫功能的调节、细胞与细胞的识别、细胞间物质的运输、癌症的诊断与治疗等有着密切的关系。多糖在医药上还是一种很好的佐剂。近年来又发现多糖的糖链在分子生物学中具有决定性作用。此外它还能控制细胞的分裂和分化,调节细胞的生长和衰老。多糖在食品工业、发酵工业及石油工业上也有着广泛的应用。因此,在开展多糖资源的开发、多糖结构的分析、多糖药理作用等的研究方面,人们做了大量的工作。2多糖的来源多糖广泛存在于植物、微生物(细菌和真菌)和海藻中,来源很广。其中研究得较早且最多的,是从细菌中得到的各种荚膜多糖,它在…     

半胱氨酸的生物代谢及其在动物生产中的应用研究进展

半胱氨酸是一种半必需含硫氨基酸,其代谢途径涉及多种酶和产物,在调节生物体营养吸收、免疫功能、肠道修复和缓解氧化应激等方面起着重要作用。目前,国内外学者在动物营养学、细胞免疫学中针对半胱氨酸的研究,极大地提升了其在农业生产实践运用的可能性。本文综述了生物体内半胱氨酸来源、代谢途径、代谢产物以及半胱氨酸在动物生产中的应用研究进展,探讨了其在动物生产、免疫代谢及抗氧化等方面的作用,以期为半胱氨酸在动物饲料中的研究和应用提供参考。     

两栖动物皮肤生物活性肽研究进展

生物活性肽在细胞生理以及机体代谢方面具有重要的调节作用。近些年来,研究者们在两栖动物体的皮肤分泌物中发现大量的生物活性肽。文中在查阅大量的相关文献基础上,对两栖动物皮肤中分泌的生物活性肽的种类、来源、作用机理及相关的生理作用等进行了综述,以期为扩大生物活性肽的研究与应用提供参考。     

脂肪酸对基因表达的影响及调控

脂肪酸是一类重要的营养物质,是动物体内的能量来源,同时也是生物膜的组成成分,在细胞生化过程中也同样起着重要作用。研究发现,脂肪酸可通过对基因表达的影响,对代谢、生长发育以及细胞分化发挥重要的调控作用。真核生物基因表达的调控大致可分为转录前、转录、转录后、翻译和翻译后等5个阶段的调控。脂肪酸通过细胞膜受体信号途径和转录因子活化途径调节基因表达,而多不饱和脂肪酸主要从基因转录和mRNA的稳定性两个方面调节基因表达。文章综述了脂肪酸,尤其是多不饱和脂肪酸对基因表达的影响及调控机制。     

反刍动物CLA的合成及其营养调控措施

共轭亚油酸(CLA)是一种主要从反刍动物脂肪和牛奶产品中发现的天然活性物质,是一类含有共轭双键的十八碳二烯酸(亚油酸)异构体混合物。亚油酸和亚麻酸在反刍动物瘤胃内通过异构化和生物脱氢反应形成CLA,反式脂肪酸在动物细胞内经δ9-脱氢酶的脱氢作用也能形成CLA。饲料、瘤胃微生物、瘤胃pH以及品种等都对CLA有着重要的影响。反刍动物来源的食品是共轭亚油酸最主要的天然来源。本文就CLA在反刍动物体内的合成及营养调控措施作一综述。     

鱼类病毒性神经坏死病研究现状

鱼类病毒性神经坏死病是近年来严重危害海水鱼类,引起暴发性流行的重大病害之一。目前,已知受神经坏死病毒感染的鱼类达40多种。该病毒包括4 种血清型,即红鳍东方鲀神经坏死病毒、拟鲹神经坏死病毒、条斑星鲽神经坏死病毒、赤点石斑鱼神经坏死病毒。患病鱼常表现出游泳异常,身体失去平衡等典型神经性疾病症状。病理组织学观察可见中枢神经系统特别是脑和视网膜出现严重的坏死、空泡化。病毒可通过垂直和水平两种途径传播。关于病毒的命名、感染机制及其防治还需深入研究。     

红鳍东方鲀幼鱼赖氨酸需求量的研究

本试验旨在研究红鳍东方鲀幼鱼对饲料赖氨酸的需求量。在基础饲料中分别添加不同水平晶体赖氨酸配制成6种等氮等脂饲料(赖氨酸水平分别为1.65%、2.58%、3.18%、4.01%、4.80%、5.52%)。将体重(13.83±0.63)g红鳍东方鲀幼鱼随机放入18个养殖桶(6个组,每组3个重复,每桶30尾鱼),在室内流水系统中进行67 d的养殖试验。结果表明:随着饲料赖氨酸水平的提高,红鳍东方鲀的特定生长率、饲料效率和蛋白质沉积率均呈先升高后降低的趋势,且当赖氨酸水平为4.80%时达到最高,显著高于1.65%赖氨酸组(P<0.05);1.65%赖氨酸组鱼体粗脂肪含量、肝体比和脏体比最高,显著高于其他组(P<0.05);随着饲料赖氨酸水平的提高,肝脏和血清谷草转氨酶活性呈先升高后降低的趋势,血清高密度脂蛋白胆固醇含量呈逐渐升高的趋势,4.80%和5.52%赖氨酸组显著高于1.65%赖氨酸组(P<0.05)。以特定生长率为评价指标进行二次回归曲线分析,得出红鳍东方鲀幼鱼对饲料赖氨酸需求量为3.83%,占饲料蛋白质的7.66%。     

Comparison of sensitivity of sodium currents to tetrodotoxin in equine muscle specimens with that in murine and human muscle specimens

OBJECTIVE: To determine sensitivity of equine skeletal muscle to tetrodotoxin and compare that with sensitivity of murine and human skeletal muscles. SAMPLE POPULATION: Semimembranosus, vastus lateralis, triceps brachii, and masseter muscle specimens from 22 euthanatized horses, vastus lateralis muscle biopsy specimens from 25 clinically normal humans, and diaphragmatic muscle specimens from 6 mice. PROCEDURE: Electrically elicited twitch responses were measured in muscle specimens incubated in medium alone and with tetrodotoxin (100 nM, 400 nM, 1.6 microM for equine specimens and 100 nM, 200 nM, 400 nM, 800 nM, 1.6 microM for murine and human specimens). Percentages of tetrodotoxin-sensitive and -resistant sodium channels were determined and compared among muscles and species. RESULTS: 2 sodium channels with different sensitivities to tetrodotoxin were identified in equine muscle. One was blocked with 100 nM tetrodotoxin and the other was unaffected by tetrodotoxin at concentrations up to 1.6 microM. The only difference detected among the 4 equine muscles was that masseter muscle specimens had a higher percentage of tetrodotoxin-sensitive channels than triceps brachii muscle specimens. Tetrodotoxin-resistant sodium channels constituted 31 to 66% of the equine muscle twitch response, which was greater than that determined for normal human and murine muscle (< 5%). CONCLUSION AND CLINICAL RELEVANCE: Equine skeletal muscle contains a high percentage of tetrodotoxin-resistant sodium channels. The 4 equine muscles evaluated were more similar to each other than to murine and human muscles. Shifts in expression of sodium channel subtypes may play a role in the manifestation of certain myopathies.     

CREBRF基因及其功能研究进展

繁殖性状作为多基因控制的数量性状,受到多种转录调控因子、信号通路的共同调控,直接影响规模化养殖生产的经济效益,提高繁殖力已成为当今家畜遗传育种的重要目标之一。Luman/CREB3募集因子(LRF或CREBRF)是一种未折叠蛋白应答响应亮氨酸拉链转录因子,其在进化过程中保持稳定且具有保守的蛋白结构。近年来的研究发现,CREBRF基因在机体代谢、疾病治疗以及动物繁殖调控过程中发挥着重要功能。本文主要就CREBRF基因的发现与结构特征、表达规律及其与动物繁殖相关的研究进展进行综述,为深入挖掘CREBRF基因在动物机体中的生物学功能奠定基础。     

Intra-articular injections for joint disease in horses.

Lameness remains an important source of reduced performance in many types of horses. Pain referable to joints is among the most common causes, and intra-articular injections remain a common and important means of addressing lameness referable to joints in horses.     

Serotypes of Streptococcus agalactiae cultured from dairy milk samples in Québec

Streptococcus agalactiae remains an important pathogen of dairy herds in Québec, but data about antigenic characteristics of this microorganism are sparse. This study was conducted to determine the variety of S. agalactiae serotypes in dairy herds in Québec. Two hundred and ninety-five isolates cultured from the milk of individual cows from 7 regions of Québec were serotyped. Sixty-two percent of the isolates were untypable. Among the 38% of typeable isolates, serotype III was found most frequently. In conclusion, the heterogeneity found among antigenic determinants of isolates from bovine milk suggests that an immunological method for the detection of S. agalactiae performed directly on bovine milk would not be a practical approach.     

Identification and characterization of IgA1 protease from Streptococcus suis

Streptococcus suis (S. suis) is a major swine pathogen and an emerging zoonotic agent. However, the current understanding of the S. suis pathogenesis of infection remains limited. In the present study, an IgA1 protease of S. suis was identified for the first time. The protein was recombinantly expressed in Escherichia coli, and the purified recombinant protein showed good cleaving reactivity to IgA1 and was highly immunoreactive to convalescent sera. The gene was found to exist in most pathogenic strains but scarcely in non-invasive isolates. These findings suggested that the IgA1 protease might play an important role in the pathogenesis of S. suis.     

Rhabdomyolysis as a complication of canine babesiosis

Rhabdomyolysis was diagnosed in two dogs with babesiosis. The first animal presented with muscle pain and caramel-coloured urine, and had markedly elevated serum myoglobin and muscle enzymes. Acute renal failure complicated the clinical picture. The second dog exhibited muscle pain and tremors, together with neurological signs and pulmonary oedema, and died soon after admission. Muscle necrosis and haemorrhage were found at necropsy. In human malaria, a disease clinically similar to canine babesiosis, rhabdomyolysis is unusual, but clinically silent muscle damage appears to be common. Likewise, biochemical evidence of muscle damage is readily found in experimental bovine babesiosis. Muscle enzymes were mildly elevated in three dogs with severe babesiosis and pigmenturia but there was no obvious muscle damage, indicating that this might also apply to canine babesiosis. The pathogenesis of infection-associated rhabdomyolysis and acute renal failure remains unclear, but inflammatory cytokines and nitric oxide could play an important role.     

Modulation of electrogenic transport processes in the porcine proximal colon by enteric neurotransmitters

The aim of our study was to evaluate the involvement of essential pro- and antisecretory neurotransmitters in regulation of secretion in porcine proximal colon. Choline acetyltransferase (ChAT), nitric oxide synthase (NOS), vasoactive intestinal peptide (VIP), substance P (SP), somatostatin (SOM) and neuropeptide Y (NPY) were located immunohistochemically in the epithelium and subepithelial layer. Modulation of epithelial secretion was studied in Ussing chambers. Application of carbachol (CA), sodium nitroprussid (SNP), VIP and SP but not of NPY or SOM resulted in a chloride dependent increase in short circuit current (I(sc) ). I(sc) increase induced by CA, VIP or SNP was not altered by preincubation with tetrodotoxin or indomethacin. In contrast, SP-induced I(sc) increase was diminished by preincubation with tetrodotoxin, indomethacin, L-nitro-arginin-methyl-ester, and atropine but not hexamethonium. Simultaneous application of CA and VIP, or CA and SNP increased the I(sc) stronger as expected. Applying SP/CA led to a smaller increase in I(sc) as calculated. It is concluded that mainly prosecretory neurotransmitters are involved in regulation of colonic secretion. Cross-potentiations of acetylcholine and nitric oxide and acetylcholine and VIP suggest activation of different intracellular cascades. Similar intracellular pathways may be stimulated by acetylcholine and SP, thus preventing an additive effect of the transmitters.     

TOADFISH POISONING (TETRODOTOXIN) IN THE CAT

SUMMARY Two cases of tetrodotoxin (toadfish) poisoning in the cat are reported. The pharmacological and physiological actions of the toxin and treatment of this intoxication are discussed.