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。     

鸡白介素-6(ChIL-6)基因的克隆与序列分析

分别用鸡传染性法氏囊病病毒感染和用ConA免疫刺激健康鸡，无菌取处理鸡的脾脏，匀浆后用Tr-izol抽提细胞总RAN，应用随机引物反转录获得cDNA，设计引物，经PCR扩增获得鸡白介素-6（ChIL-6)基因，应用pGEM-T载体克隆该基因，经测序，表明其与Gene Bank中公布的唯一的一个ChIL-6基因为同源基因。     

鸡白细胞介素-6原核表达及双抗夹心ELISA方法的建立

应用分子生物学技术原核表达ChIL-6，以ChIL-6重组蛋白为免疫原，按免疫程序分别制备兔抗和鼠抗IL-6重组蛋白的多克隆抗体。应用此抗体建立双抗夹心EL-ISA方法后，为了优化此方法本试验对该方法的最佳试验条件、标准曲线、重复性和初步应用进行确定。结果显示，经SDS-PAGE和Western-blot分析，表明ChIL-6在大肠杆菌中正确表达，为了建立检测ChIL6的双抗夹心ELISA方法，本试验应用表达的重组蛋白制备兔抗和鼠抗多克隆抗体。建立的双抗夹心ELISA方法最佳反应条件为包被抗体的质量浓度为50mg／L，4℃过夜；酶标二抗稀释度为1：400，37。C1h；应用该方法检测感染金黄色葡萄球菌后的ChIL-6，其结果与本实验室之前应用人的ELISA试剂盒检测的结果相似。结果表明，本试验建立的检测ChlL-6的双抗夹心ELISA方法可用于临床。     

安义瓦灰鸡早期生长规律研究

通过对不同羽速基因及不同性别安义瓦灰鸡的早期生长规律进行研究,结果表明:不同性别安义瓦灰鸡的早期生长规律有较大差异(P<0.01),不同羽速基因安义瓦灰鸡的早期生长规律差异不显著;安义瓦灰鸡的生长速度与出壳重无关,出壳重只影响其育雏期的体重;性别对体重的影响较晚,且公鸡大于母鸡。     

百里香精油的生物学功能及其在鸡生产中的应用

本文就百里香精油的生物学功能及其在鸡生产中的应用研究作一综述。     

基于18S rRNA的鸡组织滴虫病PCR诊断方法的建立

河南某鸡场约4周龄鸡疑似发生鸡组织滴虫病.根据鸡组织滴虫18 S rRNA序列设计引物,提取肝脏、盲肠内客物寄生虫DNA,采用PCR方法检测.结果表明,PCR扩增到与预期大小一致的产物,经测序比对,证实为鸡组织滴虫感染.所建立的PCR方法具有灵敏、特异、快速等优点,不仅能用于鸡组织滴虫病临床诊断,还能用于开展流行病学研...     

鸡Lpin1基因3′-UTR遗传变异及其对miRNA结合位点的潜在效应

【目的】研究鸡Lpin1基因3′-UTR遗传变异/单倍型及其在品种间的分布，并预测这些变异对miRNA结合位点的潜在效应。【方法】根据鸡Lpin1基因组序列（GenBank登录号：NC_006090）设计一对特异性引物，采用PCR直接测序结合克隆测序的方法，进行鸡Lpin1基因3′-UTR及其邻近外显子在品种间的遗传变异/单倍型分析。【结果】①从6个品种中发现了8个变异位点，包含两个插入/缺失变异。这些变异均位于鸡Lpin1基因的3′-UTR，3′-UTR的变异频率为17SNPs/kb；②在鸡Lpin1基因3′-UTR区域，从固始鸡、卢氏绿壳蛋鸡中分别检测到7个变异位点，未检测到河南斗鸡品种内的变异；③用次要等位基因频率≥5%的6个变异位点（g.11A＞T，g.77C＞G，g.108_109delinsG，g.110_111delinsG，g.270A＞G和g.348G＞T）进行单倍型的构建和分析，从6个品种鸡中共检测到6种单倍型，其中P1和P4单倍型是群体的优势单倍型，频率均大于30%，河南斗鸡仅包含一种单倍型；④g.77C＞G变异可引起多个miRNA结合位点的增加/丢失。【结论】鸡Lpin1基因3′-UTR具有丰富的变异，3′-UTR变异位点/单倍型在品种间的分布存在明显的差异。