鸡FKBP5基因的克隆、生物信息学及组织表达谱分析

本研究旨在对鸡FK506结合蛋白5(FK506 binding protein 5,FKBP5)基因进行克隆和生物信息学分析,并检测其在鸡不同组织中的表达量。以鸡脾脏cDNA为模板,通过PCR方法扩增和克隆鸡FKBP5基因完整CDS区序列,并进行同源性比对及系统进化树构建;使用在线软件分析FKBP5蛋白的理化性质、疏水性、跨膜结构、信号肽、二级结构和三级结构;利用实时荧光定量PCR检测其在肢体内外翻畸形(valgus-varus deformity,VVD)组肉鸡和正常组肉鸡组织中的表达量,并绘制组织表达谱。结果显示,鸡FKBP5基因CDS区序列全长1350 bp,编码449个氨基酸;同源性比对和进化树分析表明,鸡FKBP5基因氨基酸序列与鹌鹑、鸭、壁虎、中华鳖、小鼠、人、猪、斑马鱼的同源性分别为98.4%、96.2%、85.8%、87.4%、81.1%、85.2%、86.1%和61.2%,与鹌鹑、鸭的亲缘关系最近,爬行类和哺乳类动物次之,与斑马鱼(鱼类)亲缘关系最远。鸡FKBP5蛋白分子质量为50.43 ku,理论等电点(pI)为5.94,半衰期为30 h,肽链N端为蛋氨酸(Met),不稳定系数为23.80,属于稳定蛋白;跨膜区和信号肽预测结果显示,FKBP5蛋白不属于跨膜蛋白和分泌型蛋白。结构域分析结果表明,该蛋白包括2个FKBP型肽基脯氨酰异构酶(FKBP-type peptidylprolyl isomerases)、3个四肽重复(TPR)序列,主要包含α-螺旋(46.77%)、延伸链(12.47%)和无规则卷曲(40.76%),且该蛋白与HSPA2、PPID、STIP1、HSP90AA1和HSP90AB1等互作蛋白具有很强的相关性。实时荧光定量PCR结果显示,FKBP5基因在鸡各组织中广泛表达,其中在软骨和法氏囊中表达量较高,在发病组肉鸡组织中的表达量均高于正常组肉鸡,且在心脏、腿肌、法氏囊、胸腺、软骨中表达量差异显著(P<0.05),在脾脏中表达量差异极显著(P<0.01)。本试验结果可为肉鸡骨骼疾病及腿部健康选育提供参考。     

Phylogenetic analysis of Myanmar indigenous chickens using mitochondrial D-loop sequence reveals their characteristics as a genetic resource

Myanmar indigenous chickens play important roles in food, entertainment, and farm business for the people of Myanmar. In this study, complete mitochondrial D-loop sequences (1232 bp) were analyzed using 176 chickens, including three indigenous breeds, two fighting cock populations, and three indigenous populations to elucidate genetic diversity and accomplish a phylogenetic analysis of Myanmar indigenous chickens. The average haplotype and nucleotide diversities were 0.948 ± 0.009 and 0.00814 ± 0.00024, respectively, exhibiting high genetic diversity of Myanmar indigenous chickens. Sixty-four haplotypes were classified as seven haplogroups, with the majority being haplogroup F. The breeds and populations except Inbinwa had multiple maternal haplogroups, suggesting that they experienced no recent purifying selection and bottleneck events. All breeds and populations examined shared haplogroup F. When 232 sequences belonging to haplogroup F (79 from Myanmar and 153 deposited sequences from other Asian countries/region) were analyzed together, the highest genetic diversity was observed in Myanmar indigenous chickens. Furthermore, Myanmar indigenous chickens and red junglefowls were observed in the center of the star-like median-joining network of 37 F-haplotypes, suggesting that Myanmar is one of the origins of haplogroup F. These findings revealed the unique genetic characteristic of Myanmar indigenous chickens as important genetic resources.     

鸡白痢沙门氏菌鸡胚感染模型建立方法的筛选

为筛选出理想的鸡白痢沙门氏菌宿主感染模型的建立方法,本研究通过选择不同接种方式配合不同菌液浓度接种不同胚龄鸡胚建立感染模型,将90枚SPF鸡胚随机分成9组,每组10枚,分别为A、B、C、D、E、F、G、H、I组,A组为空白对照组,其余各组为模型组,模型组分别以气室接种、蛋壳接触接种的方式对不同胚龄（11和14胚龄）SPF鸡胚接种不同浓度（1×10³、3×10³、9×10³、3×10⁵、9×10⁵ CFU/mL）的鸡白痢沙门氏菌C79-3菌株。每天观察情况直至出雏,待雏鸡孵出后按组分笼饲养,每隔12 h观察1次,连续观察7 d,观察各组雏鸡的临床症状、死亡情况,观察期结束对死亡和存活雏鸡进行剖检、组织病理学检查及鸡白痢沙门氏菌的分离鉴定。结果显示,各模型组均有雏鸡出现明显的鸡白痢病症状并死亡,相较于其他模型组,以11胚龄蛋壳接触感染方式接种9×10⁵ CFU/mL的C79-3菌液的F组和14胚龄气室感染方式接种3×10³ CFU/mL C79-3菌液0.1 mL的H组,鸡胚出壳率较高,可分别达到80%和90%,出壳雏鸡呈现明显鸡白痢病特征,剖检可见肝脏出血、盲肠膨大、卵黄囊吸收不良;组织病理切片可观察到肝脏、盲肠、心脏各有不同程度的损伤,发病率分别100%和88.8%,并且鸡白痢沙门氏菌阳性检出率分别达70%和90%。本研究结果表明,以11胚龄蛋壳接触感染方式接种0.1 mL 9×10⁵ CFU/mL的C79-3菌液和14胚龄以气室感染方式接种0.1 mL 3×10³ CFU/mL的C79-3菌液的两种方法均可用于建立稳定的鸡白痢沙门氏菌宿主感染模型。     

鸡呼吸道疾病鉴别诊断与防治

呼吸道疾病是目前威胁鸡养殖产业健康发展的一类重大动物疫病,呼吸道疾病的病原种类多种多样,且造成的临床症状大致相同,诊断难度较大,如果没有进行妥善有效的鉴别、诊断,易造成整体的治疗方案缺乏针对性,难以在短时间内控制病情,错过最佳的防控时期。鸡呼吸道疾病常常混合感染并发感染,2种以上的病原相互叠加表现的临床症状复杂,诊断难度更大。该文主要论述鸡呼吸道疾病的鉴别诊断和防治措施。     

Starch digestion rates in multiple samples of commonly used feed grains in diets for broiler chickens

In this study the starch digestion rates in broiler chickens from 18 samples of 5 commonly used feed grains (sorghum, wheat, maize, barley, triticale) were determined. The methodology to determine starch digestion rates in poultry is detailed herein. Starch digestion rates were not significantly different (P = 0.128) across the 18 feed grains, which reflects the wide variations that were observed within a given feedstuff. Nevertheless, starch digestion rates in broiler chickens offered wheat-based diets were significantly more rapid by 56.0% (0.117 versus 0.075 min⁻¹; P = 0.012) than their sorghum-based counterparts on the basis of a pair-wise comparison. In descending order, the following starch digestion rates were observed: wheat (0.117 min⁻¹), barley (0.104 min⁻¹), triticale (0.093 min⁻¹), maize (0.086 min⁻¹), sorghum (0.075 min⁻¹). The implications of these findings are discussed as they almost certainly have implications for poultry nutrition and the development of reduced crude protein diets for broiler chickens.     

Glucagon‐related peptides and the regulation of food intake in chickens

The regulatory mechanisms underlying food intake in chickens have been a focus of research in recent decades to improve production efficiency when raising chickens. Lines of evidence have revealed that a number of brain‐gut peptides function as a neurotransmitter or peripheral satiety hormone in the regulation of food intake both in mammals and chickens. Glucagon, a 29 amino acid peptide hormone, has long been known to play important roles in maintaining glucose homeostasis in mammals and birds. However, the glucagon gene encodes various peptides that are produced by tissue‐specific proglucagon processing: glucagon is produced in the pancreas, whereas oxyntomodulin (OXM), glucagon‐like peptide (GLP)‐1 and GLP‐2 are produced in the intestine and brain. Better understanding of the roles of these peptides in the regulation of energy homeostasis has led to various physiological roles being proposed in mammals. For example, GLP‐1 functions as an anorexigenic neurotransmitter in the brain and as a postprandial satiety hormone in the peripheral circulation. There is evidence that OXM and GLP‐2 also induce anorexia in mammals. Therefore, it is possible that the brain‐gut peptides OXM, GLP‐1 and GLP‐2 play physiological roles in the regulation of food intake in chickens. More recently, a novel GLP and its specific receptor were identified in the chicken brain. This review summarizes current knowledge about the role of glucagon‐related peptides in the regulation of food intake in chickens.     

Genetic and non-genetic factors influencing KLH binding natural antibodies and specific antibody response to Newcastle disease in Kenyan chicken populations

This study aimed at investigating the influence of genetic and non-genetic factors on immune traits to inform on possibilities of genetic improvement of disease resistance traits in local chicken of Kenya. Immune traits such as natural and specific antibodies are considered suitable indicators of an individual's health status and consequently, used as indicator traits of disease resistance. In this study, natural antibodies binding to Keyhole Limpet Hemocyanin (KLH-NAbs) was used to measure general disease resistance. Specific antibodies binding to Newcastle disease virus (NDV-IgG) post vaccination was used to measure specific disease resistance. Titers of KLH-NAbs isotypes (KLH-IgM, KLH-IgG and KLH-IgA) and NDV-IgG were measured in 1,540 chickens of different ages ranging from 12 to 56 weeks. A general linear model was fitted to determine the effect of sex, generation, population type, phylogenetic cluster, line, genotype and age on the antibody traits. A multivariate animal mixed model was fitted to estimate heritability and genetic correlations among the antibody traits. The model constituted of non-genetic factors found to have a significant influence on the antibody traits as fixed effects, and animal and residual effects as random variables. Overall mean (±SE) concentration levels for KLH-IgM, KLH-IgG, KLH-IgA and NDV-IgG were 10.33 ± 0.04, 9.08 ± 0.02, 6.00 ± 0.02 and 10.12 ± 0.03, respectively. Sex, generation and age (linear covariate) significantly (p < 0.05) influenced variation across all the antibody traits. Genotype effects (p < 0.05) were present in all antibody traits, apart from KLH-IgA. Interaction between generation and line was significant (p < 0.05) in KLH-IgM and NDV-IgG while nesting phylogenetic cluster within population significantly (p < 0.05) influenced all antibody traits, apart from KLH-IgA. Heritability estimates for KLH-IgM, KLH-IgG, KLH-IgA and NDV-IgG were 0.28 ± 0.08, 0.14 ± 0.06, 0.07 ± 0.04 and 0.31 ± 0.06, respectively. There were positive genetic correlations (0.40–0.61) among the KLH-NAbs while negative genetic correlations (−0.26 to −0.98) were observed between the KLH-NAbs and NDV-IgG. Results from this study indicate that non-genetic effects due to biological and environmental factors influence natural and specific antibodies and should be accounted for to reduce bias and improve accuracy when evaluating the traits. Subsequently, the moderate heritability estimates in KLH-IgM and NDV-IgG suggest selection possibilities for genetic improvement of general and specific immunity, respectively, and consequently disease resistance. However, the negative correlations between KLH-NAbs and NDV-IgG indicate the need to consider a suitable approach that can optimally combine both traits in a multiple trait selection strategies.     

酸化剂、微生态制剂和寡糖对‘麒麟鸡’生长性能和消化道酶活力的影响

为了研究酸化剂、微生态制剂和寡糖单独和联合添加对‘麒麟鸡’生长性能和消化道酶活力的影响,选择健康1日龄‘麒麟鸡’192只,随机分成8个处理组,每个处理组3个重复,每个重复8只鸡,采用L8(23)完全正交试验设计进行试验,酸化剂水平为0、0.15%,微生态制剂水平为0、0.15%,寡糖水平为0、0.10%,试验期28天。结果表明:单独添加0.15%酸化剂可提高‘麒麟鸡’生长性能、消化酶活力;单独添加0.15%微生态制剂对‘麒麟鸡’生长性能无显著影响,可提高胃蛋白酶活力;单独添加0.10%寡糖可降低‘麒麟鸡’生长性能和胃蛋白酶活力;0.15%酸化剂、0.15%微生态制剂和0.10%寡糖2种或3种联合添加对提高‘麒麟鸡’生长性能和消化酶活力的互作效应不明显。     

内毒素对仔鸡血浆SOD活性及MDA水平的影响

为了探讨大肠埃希菌O55∶B5的内毒素(LPS)对仔鸡的损伤机理,将168只仔鸡随机分成4组(n=42),即对照组,100 mg/kgLPS组,200 mg/kg LPS组,300 mg/kg LPS组。灌服内毒素后,分别于2,4,8,12,24,48 h和72 h处死鸡(各时间点均为6只),测定血浆SOD活性和MDA浓度。结果表明,与对照组相比,各剂量组鸡血浆SOD活性均明显降低,MDA含量均明显升高(P<0.05)。且各剂量组之间SOD活性随攻毒剂量的增加而降低,随时间的延长先降低后升高;MDA含量随攻毒剂量的增加而升高,随时间的延长先升高后降低。表明一定量内毒素能诱发鸡体内氧自由基的产生,显著降低机体中SOD的活性和提高MDA的含量。     

鸡生长发育早期骨骼肌IGF1R mRNA表达规律研究

以生长速度不同的花山麻鸡和清远麻鸡为试验素材,采用实时荧光定量PCR方法检测鸡9、12、16、21胚龄(E9 d、E12 d、E16 d、E21 d)和出雏后7日龄(7 d)时胸肌和腿肌中IGF1R mRNA表达变化情况,并与肌肉质量进行相关性研究。结果发现,21胚龄时,花山麻鸡和清远麻鸡胸肌质量都出现了显著降低,腿肌质量持续增长。花山麻鸡胸肌IGF1R mRNA表达呈前高后低趋势,9胚龄时表达量最高,之后显著降低并维持在较低的水平,出雏后7日龄时表达量再次下降;清远麻鸡在胸肌中的表达则呈“波浪形”,9胚龄和16胚龄表达量升高,其他日龄表达量显著降低。腿肌中,花山麻鸡IGF1R mRNA表达量在16胚龄之后显著降低;清远麻鸡腿肌IGF1R mRNA表达呈依次递减模式,各时间点之间差异显著(P<0.05)。品种间各个时间点胸肌和腿肌IGF1R mRNA表达量均呈显著差异(P<0.05)。两个品种骨骼肌IGF1R mRNA表达与胸肌、腿肌质量均呈极显著相关(P<0.01)。以上结果初步揭示了生长发育早期不同品种鸡胸肌和腿肌IGF1R基因表达发育变化趋势和品种差异,为深入研究IGF1R基因在鸡肌肉发育中的调控机理提供基础资料。