Gene constitution of South-East Asian native chickens, commercial chickens and jungle fowl using polymorphisms of four calpain genes

The gene constitution of polymorphisms of the four calpain genes (µ‐calpain, m‐calpain, p94, and µ/m‐calpain) were analyzed in South‐East Asian native chickens, White Leghorn and Broiler commercial chickens, and Red and Green jungle fowl. Polymorphisms were detected at all loci in chickens and Red jungle fowl, but only for CAPN1 (µ‐calpain gene) in Green jungle fowl. CAPN2 and CAPN1.5 are linked on chicken chromosome 3, and the genotype for these loci were treated as haplotype. Some combinations of calpain loci were tested using principal component analysis, and the best combination (CAPN1, CAPN3, and CAPN1.5) was determined. The proportion of polymorphic loci (P_poly) and heterozygosity (H?) were 1.00 and 0.316–0.465 in domestic chickens and red jungle fowl, and 0.33 and 0.137 in Green jungle fowl, respectively. G_ST values suggested that the degree of subdivision among native chickens was relatively low except for Thailand, which was highest. Pair‐wise F_ST testing, dendrogram and principal component analysis from the results of calpain loci showed that the four South‐East Asian native and commercial chicken populations were close genetically.     

Cytogenetic mapping of 11 functional genes to chicken chromosomes by fluorescence in situ hybridization

With chicken bacterial artificial chromosome (BAC) DNA as probes, 11 non‐assigned functional genes were localized to chicken chromosomes 1 or 2 by fluorescence in situ hybridization (FISH). The 11 genes and their chromosomal positions are as follows: ALVEB5, 1p26‐24; ACO2, 1p16‐14; HSP108, 1p14‐13; CD4, 1q11; HSD3B; 1q11; SOD1, 1q14‐21; LAMP1, 1q24‐31; P2Y5, 1q35‐36; EN2, 2p31‐24; NPY, 2p14‐13 and CA2, 2q31‐32. Metaphase chromosome spreads used for hybridization were prepared from embryonic chicken fibroblast cultures. The gene position was identified according to the international standardized G‐banded karyotype of chicken by measuring the relative fractional length from the telomere of the p‐arm to the hybridization signal (FLpter). The 11 genes mapped newly will enrich the cytogenetic map and serve as additional anchor markers for integrating the cytogenetic map with the genetic map of chicken.     

Analysis of FMO genes and off flavour in pork

Off flavours in pork sometimes produce tastes such as sourness, fishy, metallic or other non‐typical flavours and are often caused by low pH. Loss of function mutations in flavin containing mono‐oxygenase 3 (FMO3) are known to be associated with a fishy off flavour in both chicken eggs and cow's milk and a similar autosomal recessive disorder is present in humans resulting in a fishy odour. FMO3 is a member of a gene family that is clustered on human chromosome 1. Comparative mapping suggested that FMO3 and the remaining FMO genes (ex. FMO1 and FMO5) might map to the orthologous region on pig chromosome 9 (SSC9) where a quantitative trait locus (QTL) for off flavour was previously identified. Primers were designed to amplify FMO1, FMO3 and FMO5 gene fragments and several SNPs were discovered and genotyping tests developed. The genotypes from the Iowa State University Berkshire × Yorkshire resource population were used to linkage map FMO1 and FMO3 to SSC9 and FMO5 to pig chromosome 4 (SSC4). QTL and associations analyses were performed using the map containing FMO1 and FMO3. Results demonstrated that FMO3 and FMO1 mapped less than 1 cM away from the peak for the off flavour QTL previously detected on SSC9 and provide indications of an association between the FMO3 polymorphism and off flavour in pork.     

The normalisation of CAPN gene expression in M. pectoralis superficialis in broiler lines differing in growth rate and their relationship to breast muscle tenderness

1. The aim of this study was to assess mRNA abundance of calpain 1 (CAPN1) and calpain 3 (CAPN3) in breast muscle of 80 fast-growing (FG) and slow-growing broilers (SG) and relate gene expression in relation to growth and Warner Bratzler (WB) shear force of breast muscle.

2. The expression of CAPN1 and CAPN3 genes was higher in the FG compared to the SG line, but significant results were obtained only for CAPN1. The CAPN1 mRNA level was strongly dependent on line and gender interaction.

3. Lower values of shear force were observed in the FG line, where a higher level of calpain expression was shown.

4. A new panel of housekeeping genes (RPL4 and SDHA) for normalisation of gene expression in muscle tissues could be used in other studies of gene expression in chicken.

     

微卫星标记与鸡蛋品质性状关系的研究

本试验分别对60周龄文昌鸡和新扬州鸡进行了蛋品质的测定,测定了8个性状为:蛋重、蛋壳重、蛋壳厚度、蛋壳强度、哈氏单位、蛋形指数、蛋黄重、蛋黄颜色。通过统计软件,对各蛋品质性状进行了相关分析,并通过选用20对微卫星标记,筛选出了与哈氏单位、蛋重有关的分子遗传标记。结果表明:与60周龄新扬州鸡的哈氏单位有关的标记为2号染色体上MCW239和4号染色体上的ADL260,与60周龄新扬州鸡的蛋重有关的标记为2号染色体上的ADL176和MCW239,与60周龄新扬州鸡蛋壳强度有关的标记Z染色体上的LEI229;而与60周龄文昌鸡哈氏单位相关的有2号染色体的的ADL176、MCW239和4号染色体的MCW240,与60周龄文昌鸡蛋重相关的是4号染色体上的标记LEI119,与60周龄蛋壳强度相关的标记为Z染色体上的MCW246和LEI229。     

FISH mapping of 10 canine BAC clones harbouring genes and microsatellites in the arctic fox and the Chinese raccoon dog genomes

Cytogenetic mapping of the arctic fox and the Chinese raccoon dog were performed using a set of canine probes derived from the Bacterial Artificial Chromosome (BAC) library. Altogether, 10 BAC clones containing sequences of selected genes (PAX3, HBB, ATP2A2, TECTA, PIT1, ABCA4, ESR2, TPH1, HTR2A, MAOA) and microsatellites were mapped by fluorescence in situ hybridization (FISH) experiments to chromosomes of the canids studied. At present, the cytogenetic map on the arctic fox and Chinese raccoon dog consists of 45 loci each. Chromosomal localization of the BAC clones was in agreement with data obtained by earlier independent comparative chromosome painting. However, two events of telomere‐to‐centromere inversions were tentatively identified while compared with assignments in the dog karyotype.     

Genetic mapping of the QTL affecting body weight in chickens using a F2 family

1. To identify the quantitative trait loci (QTL) affecting growth in chickens, we carried out QTL analysis on chicken growth traits using a population of 227 F2 crosses between a Satsumadori (slow-growing, light-weight Japanese native breed used as a meat chicken) male and a White Plymouth Rock (early-maturing, heavy weight broiler). 2. We chose 78 microsatellite loci from 331 publicly available on 14 linkage groups, with respect to their utility and location. 3. Two QTLs affecting body weight at 13 and 16 weeks were mapped at 220 cM on chromosome 1 (LOD scores, 2.8 and 4.5, respectively, at 13 and 16 weeks), and at 60 cM on chromosome 2 (LOD scores, 6.2 and 8.1, respectively, at 13 and 16 weeks). 4. The closest loci to the QTLs were LEI71 on chromosome 1 and LMU13 and MCW184 on chromosome 2. 5. The sites of the QTLs agreed closely with those already reported. Therefore, it seems likely that QTLs affecting growth of chickens are located at these sites.     

Protective effect of sodium glutamate and sorbitol on thermal denaturation of chicken and croaker actomyosin

The thermal protective effect (E‐Value) of sodium glutamate (Na‐Glu) on chicken and croaker actomyosin (AM) was significant but decreased slightly with increasing concentration. The E‐value of chicken AM with Na‐Glu was 1.11 mol/L^?1 at 0–0.75 mol/L and decreased to 0.4 mol/L^?1 at 0.75–1.5 mol/L. Likewise, the E‐value of croaker AM with Na‐Glu was 1.51 mol/L^?1 at 0–1 mol/L and decreased to 0.2 mol/L^?1 at 1–1.5 mol/L. Sorbitol showed a steady thermal protective effect on chicken and croaker AM. The E‐values of chicken and croaker AM at 0 to 1.5 mol/L sorbitol were 0.71 mol/L^?1 and 0.59 mol/L^?1, respectively. The protective effect of sorbitol on both types of AM was greater than that of Na‐Glu. Higher concentrations of Na‐Glu with chicken and croaker AM gave a decrease in viscosity number and turbidity. Higher concentrations of Na‐Glu caused internal aggregation of AM and the protective effect of Na‐Glu was decreased. The results of this experiment confirmed that Na‐Glu and sorbitol have different modes of action and ability to control the thermal denaturation of chicken and croaker AM.     

Basic characterization of avian β‐defensin genes in the Japanese quail,Coturnix japonica

In this study, we identified a cluster of 14 avian β‐defensins (AvBD; approximately 66 kbp) in the Japanese quail, Coturnix japonica. Except for AvBD12 (CjAvBD12) and ‐13, the CjAvBDs coding sequences exhibited greater than 78.0% similarity to the respective orthologous chicken AvBD genes (GgAvBD). The putative amino acid sequence encoded by each CjAvBD contained six cysteine residues and the GXC (X1‐2) motif considered essential for the β‐defensin family. Each CjAvBDs also formed a sub‐group with the respective orthologous genes of various bird species in a phylogenetic tree analysis. Synteny between the CjAvBD cluster and GgAvBD cluster was confirmed. The CjAvBD cluster was mapped on the long‐arm end of chromosome 3 by linkage analysis based on single nucleotide polymorphisms (SNPs) of CjAvBD1 and CjAvBD12 (approximately 46kbp), as well as GgAvBD cluster. We also confirmed that CjAvBD1, ‐4, ‐5, ‐9, and ‐10 are transcribed in 20 tissues, including immune and digestive tissues. However, our experimental data indicated that the CjAvBD cluster lacks the AvBD3 and ‐7 loci, whereas the CjAvBD101α, ‐101β, and ‐101θ loci arose from gene duplication of the AvBD6 orthologous locus in the CjAvBD cluster after differentiation between Coturnix ‐ Gallus.     

Effect of chicken leptin recptor short hairpin RNA on expression of JAK2, STAT3, SOCS3 and CPT1 genes in chicken preadipocytes

In this study, we detect depressive effect on leptin receptor (LEPR) by LEPR‐specific short hairpin RNA (shRNA) expression plasmids in chicken preadipocytes, and effect on messenger RNA (mRNA) expression levels of genes related to signal transduction, including JAK2, STAT3, SOCS3 as well as CPT1, which is associated with fatty acid metabolism. shRNA expression vectors targeting LEPR were constructed and transfected into chicken preadipocytes. The transfection efficiency was evaluated by fluorescence microscopy. Real‐time PCR was used to detect its effect on mRNA expression levels of JAK2, STAT3, SOCS3 and CPT1. Results showed that LEPR mRNA was knocked down by 99% (P < 0.01) after transfection for 72 h. In the knockdown preadipocytes, the mRNA levels of JAK2 and CPT1 were down‐regulated by 47.56% (P < 0.01) and 42.26% (P < 0.05), respectively; while expression of STAT3 and SOCS3 increased 7.72‐fold (P < 0.01), 1.71‐fold (P < 0.01), respectively. It is concluded that knockdown of LEPR influences mRNA expression of its down‐stream genes, suggesting that chicken LEPR play a certain role in regulating genes in the complicated gene network of preadipocytes.     

Potential role of ALDH3A2 on the lipid and glucose metabolism regulated by (‐)‐hydroxycitric acid in chicken embryos

This study aimed to investigate the effect of (‐)‐hydroxycitric acid ((‐)‐HCA) on lipid and glucose metabolism, and further analyzed these actions whether associated with modulation of aldehyde dehydrogenase 3 family member A2 (ALDH3A2) expression in chicken embryos. Results showed that (‐)‐HCA decreased triglyceride content and lipid droplet counts, while these effects induced by (‐)‐HCA were reversed in chicken embryos pre‐transfected with sh4‐ALDH3A2. (‐)‐HCA decreased malic enzyme, acetyl‐CoA carboxylase, fatty acid synthase, and sterol regulatory element binding protein‐1c mRNA level, while increased carnitine palmitoyl transferase 1A (CPT1A) and peroxisome proliferators‐activated receptor α (PPARα) mRNA level; and the action of (‐)‐HCA on lipid metabolism factors had completely eliminated in embryos pre‐transfected with sh4‐ALDH3A2. Chicken embryos pre‐transfected with sh4‐ALDH3A2 had eliminated the increasing of serum glucose and hepatic glycogen content induced by (‐)‐HCA. (‐)‐HCA decreased phosphofructokinase‐1 and increased G6P, fructose‐1,6‐bisphosphatase, phosphoenolpyruvate carboxykinase (PEPCK), and pyruvate carboxylase mRNA level in chicken embryos. Similarly, the effect of (‐)‐HCA on these key enzyme mRNA level was reversed in embryos pre‐transfected with sh4‐ALDH3A2. Furthermore, (‐)‐HCA increased PPAR‐γ‐coactivator‐1α (PGC‐1α), PPARα, hepatic nuclear factor‐4A, PEPCK, and CPT1A protein level, and these actions of (‐)‐HCA disappeared in embryos pre‐transfected with sh4‐ALDH3A2. These results indicated that (‐)‐HCA reduced fat accumulation and accelerated gluconeogenesis via activation of PGC‐1α signaling pathway, and these effects of (‐)‐HCA might associate with the increasing of ALDH3A2 expression level in chicken embryos.     

Further studies of linkage and mappings of the loci of genes in group 3 on chromosome 1 of the domestic fowl

1. Evidence is presented to confirm the placing of the extended black E‐locus in linkage Group 3 on chromosome 1, E being linked with peacomb P by 43 map units. P has been shown to be linked with dark‐brown Columbian Db and sleepy‐eye se by 32 and 45 map units, respectively, se being independent of E.

2. Evidence is also presented to demonstrate independence of E and Db; hence, Db and se have their loci on the same side of P, the gene order being E‐P‐Db‐se, thus contradicting published mappings which place P between Db and se.

3. An investigation into the deductive relationships on which published mappings are based led to the conclusion that insufficient evidence existed for the inclusion of the sub‐group comprising blood group Ea‐P, naked neck Na, silky feathering h and flightless El as part of Group 3.

4. Furthermore, it appears only 4 genes in Group 3 have actually had their loci mapped; blue egg O, P, the eumelanin extension charcoal cha and the feather growth restrictor tardy t.

5. No evidence appears to have been presented to establish on which arm of chromosome 1 any of the other genes in Group 3 have their loci. A revised map of chromosome 1 and a schematic arrangement to demonstrate the relative linkage distances of the loci of the unmapped genes in Group 3 are presented and explained.     

Mechanisms involved in the cytosolic calcium ion elevation induced by activating factors in chicken and rat phagocytes

The aim of the present study was to determine the mechanism of cytosolic calcium ion concentration [Ca²⁺]_i elevation in chicken and rat phagocytes stimulated with phorbol myristate acetate (PMA), leukotriene B₄ (LTB₄), formyl‐methionyl‐leucyl‐phenylananine (fMLP) and Saccaromyces cerevisiae culture supernatant (SCS). Pretreatment with EGTA completely suppressed the PMA‐induced [Ca²⁺]_i elevation in rat and chicken phagocytes, suggesting that all the [Ca²⁺]_i elevation induced in the PMA‐stimulated rat and chicken phagocytes was attributable to the influx of extracellular Ca²⁺. On the other hand, the elevation of LTB₄‐, FMLP‐ and SCS‐induced [Ca²⁺]_i was only partially suppressed by ethyleneglycol‐bis (β‐aminoethyl)‐N,N,N′,N′‐tetraacetic acid ethylene (EGTA) pretreatment of phagocytes. The results indicated that two pathways of [Ca²⁺]_i elevation, recruitment from the intracellular Ca²⁺ store and influx of extracellular Ca²⁺, are involved in the [Ca²⁺]_i elevation of LTB₄‐, fMLP‐ and SCS‐stimulated phagocytes. In fMLP‐stimulated rat neutrophils, [Ca²⁺]_i elevation showed a two‐phase pattern in which the time lag between the first and second phase was approximately 1 min. The EGTA treatment of the fMLP‐stimulated cells induced a reduction of the first phase level and a disappearance of the second phase. The reason for the special influence of EGTA observed in fMLP‐stimulated cells is unknown, but the disappearance of the second phase of the [Ca²⁺]_i may be elicited by the EGTA‐induced decrease of the first phase [Ca²⁺]_i elevation that depends on IP₃ and diacylglycerol induced by fMLP.     

Escherichia coli isolates from commercial chicken meat and eggs cause sepsis,meningitis and urinary tract infection in rodent models of human infections

The zoonotic potential of Escherichia coli from chicken‐source food products is important to define for public health purposes. Previously, genotypic and phenotypic screening of E. coli isolates from commercial chicken meat and shell eggs identified some E. coli strains that by molecular criteria resembled human‐source extraintestinal pathogenic E. coli (ExPEC). Here, to clarify the zoonotic risk of such chicken‐source E. coli, we compared selected E. coli isolates from chicken meat and eggs, stratified by molecularly defined ExPEC status, to human‐source ExPEC and to laboratory E. coli for virulence in rodent models of sepsis, meningitis and UTI, and evaluated whether specific bacterial characteristics predict experimental virulence. Multiple chicken‐source E. coli resembled human‐source ExPEC in their ability to cause one or multiple different ExPEC‐associated infections. Swimming ability corresponded with urovirulence, K1 capsule corresponded with ability to cause neonatal meningitis, and biofilm formation in urine corresponded with ability to cause sepsis. In contrast, molecularly defined ExPEC status and individual genotypic traits were uncorrelated with ability to cause sepsis, and neither complement sensitivity nor growth in human urine corresponded with virulence in any infection model. These findings establish that chicken‐derived food products contain E. coli strains that, in rodent models of multiple human‐associated ExPEC infections, are able to cause disease comparably to human‐source E. coli clinical isolates, which suggests that they may pose a significant food safety threat. Further study is needed to define the level of risk they pose to human health, which if appreciable would justify efforts to monitor for and reduce or eliminate them.     

家鸡豆冠基因定位的研究

构建家鸡1号染色体短臂部分连锁图谱及豆冠冠型基因的定位。通过测交选择豆冠冠型基因型纯合的2只吐鲁番斗鸡(♂)和6只玫瑰冠鸡(♀)为亲本,采用F2代试验设计建立F2代494只,依据己公布的家鸡遗传连锁图谱,分别在1号染色体上筛选了13对微卫星标记,运用MapMaker/EXP 3.0和MapDraw 2.1软件绘制遗传连锁图谱,并结合记录的表型性状值对冠型性状进行定位分析。经卡方检验F2代冠型符合9∶3∶3∶1的遗传定律。在连锁分析中除MCW0007位外,其余12个微卫星座位在试验群体中均表现较高的基因杂合度和多态信息含量。对冠型性状进行初步的分析,结果显示,MCW0428、ADL0319、LEI0174和MCW0058标记位点LOD值＞3,表明这4个微卫星位点与豆冠冠型基因存在连锁关系,其中LEI0174与豆冠基因遗传距离最近为0.12 cM。     

Effect of post‐mortem temperature on chicken M. pectoralis major: Muscle shortening and cooked meat tenderness

1. Muscle shortening, sarcomere lengths and pH values were measured in strips of chicken M. pectoralis major (PM) muscle incubated at different time (0 to 24 h) and temperature (0° to 40°C) combinations immediately after slaughter; their effects on cooking loss and meat tenderness determined.

2. Maximum muscle shortening of 39% and 43% occurred at 0°C and 40°C respectively. At 0°C, most shortening occurred within 90 min postmortem when the pH of the muscle ranged from 7.13 to 6.52. In contrast, at 40°C, most shortening occurred during the development of rigor mortis, between 90 and 380 min post‐mortem, when the muscle pH ranged from 6.16 to 5.89. In a similar manner, minimum sarcomere lengths of 1.38 μm were reached after 90 min at 0°C while more severe sarcomere shortening, to 0.96 μm and 0.86 μm at 30°C and 40°C respectively, was not complete until after 380 min post‐mortem. Between 5°C and 20°C, muscle shortening ranged from 25 to 34% while minimum sarcomere lengths of 1.33 μm were recorded.

3. Cooking losses increased on average from 7 to 16% between 30 and 380 min post‐mortem, with maximum losses of 19% being achieved by the end of the 24‐h incubation period.

4. At 0°C, shear force values increased from 2.94 kg/cm² to 4.34 kg/cm² between 30 and 90 min post‐mortem while the muscle pH was > 6.5. At all other temperatures, increases in shear force values were not detected until 380 min post‐mortem when the muscle pH had fallen to 5.9 and rigor mortis had set in. At all times after 380 min, however, the muscle strips incubated at 0, 5 and 40°C had lower shear values (range 3.17 to 5.49 kg/cm²) than those incubated from 10°C to 30°C (range 5.06 to 7.22 kg/cm²).

5. A significant quadratic relationship was found between the degree of shortening and subsequent cooked meat tenderness, in which peak toughness occurred at 30% shortening. This would suggest that the actual extent of muscle shortening per se has an important role to play in determining the tenderness of chicken post‐mortem. Consequently, with unrestrained chicken muscle, where extensive shortening occurred at 0°C and 40°C (i.e cold‐ and rigor shortening) the cooked meat was more tender than that subjected to intermediate post‐mortem temperature regimens.     

Genome‐wide association study for plasma very low‐density lipoprotein concentration in chicken

The plasma very low‐density lipoprotein (VLDL) concentration is an effective blood biochemical indicator that could be used to select lean chicken lines. In the current study, we used Genome‐wide association study (GWAS) method to detect SNPs with significant effects on plasma VLDL concentration. As a result, 38 SNPs significantly associated with plasma VLDL concentration were identified using at least one of the three mixed linear model (MLM) packages, including GRAMMAR, EMMAX and GEMMA. Nearly, all these SNPs with significant effects on plasma VLDL concentration (except Gga_rs16160897) have significantly different allele frequencies between lean and fat lines. The 1‐Mb regions surrounding these 38 SNPs were extracted, and twelve important regions were obtained after combining the overlaps. A total of 122 genes in these twelve important regions were detected. Among these genes, LRRK2, ABCD2, TLR4, E2F1, SUGP1, NCAN, KLF2 and RAB8A were identified as important genes for plasma VLDL concentration based on their basic functions. The results of this study may supply useful information to select lean chicken lines.     

Detection and Molecular Characterization of Salmonella enterica Serovar Eppendorf Circulating in Chicken Farms in Tunisia

Salmonella enterica subsp. enterica serovar Eppendorf, with antigenic formula 1,4,12,[27]:d:1,5, is an infrequent serovar. However, 14% (20 of 142) of the isolates recovered during June–July 2012 in chicken farms in Tunisia belonged to S. Eppendorf. These isolates were analysed for resistance and virulence profiles. None of them were susceptible to all antimicrobials tested, while 70%, 60%, 50%, 50%, 20% and 5% were resistant to sulphonamides (sul1, sul2 and sul3), streptomycin (aadA1‐like), trimethoprim (dfrA1‐like), nalidixic acid (GyrA Asp₈₇→Asn and not identified), gentamicin (not identified) and ampicillin (bla_TEM‐1‐like). About 30% of the isolates showed decreased susceptibility to ciprofloxacin and carried the qnrB gene; 65% of the isolates were multidrug resistant and contained class 1 integrons with sul1 or sul3 in the 3′ conserved segment. The orgA, ssaQ, mgtC, siiD and sopB virulence genes located on SPI1 to SPI5 and the fimbrial bcfC gene were present in all isolates; the sopE1 and sodC1 carried by prophages were variably detected; however, the prophage gipA gene and the spvC gene of serovar‐specific virulence plasmids were absent. Altogether, ten resistance and three virulence profiles were identified. Typing of the isolates with XbaI‐ and BlnI‐PFGE supports a close relationship, although they appear to be evolving under selective pressure probably caused by antimicrobial use in chicken husbandry. As far as we know, this is the first study investigating the molecular bases of antimicrobial drug resistance, the virulence gene content and the PFGE profiles of S. Eppendorf. The epidemiological surveillance of this serovar would be necessary to evaluate its possible impact on human health, particularly in Tunisia and other African countries where it was already reported.     

Influences of major histocompatibility complex class I haplotypes on avian influenza virus disease traits in Thai indigenous chickens

Natural infections with influenza viruses have been reported in a variety of animal species including humans, pigs, horses, sea mammals, mustelids and birds. Occasionally, devastating pandemics occur in domestic chickens (broiler and layers) and in humans. From November 2003 to March 2004 in many countries in Asia, there were outbreaks of H5N1 avian influenza virus, causing death of infected patients, and devastating the poultry industry. Some groups of Thai indigenous chickens survived and were therefore classified as resistant. These traits were related to immunogenetics, in particular, the major histocompatibility complex (MHC) class I and class II molecules. The chicken MHC class I were investigated as candidate genes for avian influenza virus disease resistance. Seven hundred and thirty Thai indigenous chickens from smallholder farms in the rural area of avian influenza virus disease outbreaks in the central part of Thailand were used in the present study. They were separated into two groups, 340 surviving chickens and 390 dead chickens (resistant and susceptible). Genomic DNA were precipitated from blood samples and feathers. The DNA were used to amplify the MHC class I gene. Data were analyzed using χ² analysis to test significant differences of influences of MHC class I haplotypes on avian influenza virus disease traits. The results represented nine MHC class I haplotypes: A1, B12, B13, B15, B19, B21, B2, B6, and BA12, and included 10 of their heterozygotes. The homozygous B21 from these collected samples had a 100% survival rate and they were the major survival group. In addition, the heterozygous B21 also had a high survival rate because of co‐dominant expression of these genes. In contrast, the homozygous B13 had a 100% mortality rate and they were the major mortality group. These results confirmed that MHC class I haplotypes influence avian influenza virus disease‐resistant traits in Thai indigenous chicken. The MHC genes can be used as genetic markers to improve disease‐resistant traits in chicken.     

Blood Lymphocyte Subpopulations, Neutrophil Phagocytosis and Proteinogram During Late Pregnancy and Postpartum in Mares

The aim of this study was to evaluate peripheral blood lymphocyte subpopulations, neutrophil phagocytic capacity and proteinogram characteristics in mares, during the last trimester of pregnancy and in postpartum. Measurement of phagocytosis and quantification of T‐lymphocyte subsets were done by flow cytometry. Quantification of T‐lymphocyte subsets was performed with monoclonal antibodies specific for CD2, CD3, CD4 and CD8 cell markers. Natural killer and B‐cell counts were estimated mathematically. Serum proteinogram was obtained by electrophoresis. No significant differences were observed between gestation and postpartum on CD4⁺, CD8⁺ and NK⁺ lymphocyte subsets, CD4 : CD8 ratio and phagocytosis. The percentage of cells expressing CD3 (64.2 ± 1.8) and CD2 (68.4 ± 1.7) (Mean ± SEM) was reduced during gestation vs postpartum (69.7 ± 1.5 and 73.8 ± 1.4 respectively) (p < 0.05). During pregnancy, CD19⁺ (31.6 ± 1.7) was higher than in postpartum (26.2 ± 1.4) (p < 0.05). Total T cells (2911 ± 227 cells/μl), T helper cells (2144 ± 169 cells/μl) and T‐cytotoxic cells (767 ± 68 cells/μl) were depressed in pregnancy, when compared with postpartum (4093 ± 337 cells/μl; 3004 ± 276 cells/μl; 1089 ± 94 cells/μl respectively) (p < 0.01). Total white blood cell count was reduced during pregnancy (8815 ± 427 cells/μl) with respect to postpartum (10742 ± 446 cells/μl) (p < 0.01), while neutrophil count did not change. Total proteins, albumin, α₁,α₂,β₁, β₂, γ globulins and albumin : globulin did not differ. Our results suggest that the physiological immune depression occurring in mares, during gestation might be due to T‐helper and T‐cytotoxic lymphocytes reduction.