Egg-type Chickens Research Articles

Detection of Extended-spectrum β-lactamase and AmpC β-lactamase Producing Escherichia coli Isolates from Chickens

The aim of this study was to investigate the presence of Extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase producing Escherichia coli strains isolated from meat and faecal samples of chicken. Faecal samples (n: 384) were collected from broiler and egg-type healthy chickens in 43 flocks and 384 fresh chicken meat samples from local markets, supermarkets and slaughterhouses. E. coli isolates were tested phenotypically according to the guidelines of CLSI (2013) for ESBL production. Phenotypic detection of AmpC production was carried out by determination of resistance to cefoxitin and susceptibility to cefepime. Also, presence of genes encoding different types of β-lactamases (blaCTX-M, blaTEM, blaSHV and the mutation in the promoter of AmpC) in all phenotypically ESBL or AmpC producing E. coli was investigated by PCR assays. In this study, blaCTX-M (95.4%), blaCTX-M-1 (81.8%), blaCTX-M-8 (4.5%), blaTEM (45.4%) and blaSHV (2.2%) genes were detected from faecal samples and blaCTX-M (100%), blaCTX-M-1 (28.5%) and blaTEM (7.1%) from meat samples. The only plasmidic AmpC β-lactamase found was the CIT type.

Evaluation of a three-way cross chicken developed for backyard poultry in respect to growth, production and carcass quality traits under intensive system of rearing

ABSTRACTObjective of the work was to develop a three-way cross for egg-type backyard chicken using male and female lines developed from exotic chickens. To improve the egg production further and to get colour plumage pattern, the two-way cross PD1 X IWI males were crossed with PD3 females to produce three-way cross (PD1 X IWI X PD3). The crossbred was evaluated for different traits upto 72 weeks of age. Sexual dimorphisms were evident from two weeks onwards for body weights and shank length differ significantly (P < .05) between male and female at 8, 12 and 16 weeks of age. Male were reared upto 16 weeks of age, and at 16 weeks, body weight of male and female were 1670 and 1096 g, respectively. Carcass quality measured at 16 week of age recorded 66.12% eviscerated carcass yield, 4.84% giblet and 0.30% abdominal fat. Egg production performance recorded from 17 to 72 weeks of age at 4 weeks interval showed significant (P < .05) difference between different periods, and peak egg production was recorded during 29–32 weeks. At 69–72 weeks period, the egg production per bird was 14.78 eggs. Egg production upto 40, 52, 64 and 72 weeks of age were 91.71, 105.84, 204.88 and 233.28 eggs, respectively. Age and weight at sexual maturity were 163.14 days and 1702 g, respectively. Egg weight recorded at 4 weeks interval starting from 20 weeks of age showed linear increase upto 56 weeks of age with significant differences at different ages. The results indicate that the cross may be of use for egg-type poultry in the backyard. However, before large-scale propagation, the cross has to be evaluated in the field.

Splenic gene expression profiling in White Leghorn layer inoculated with the Salmonella enterica serovar Enteritidis.

Salmonella enterica serovar Enteritidis (SE) is a foodborne pathogen that can threaten human health through contaminated poultry products. Live poultry, chicken eggs and meat are primary sources of human salmonellosis. To understand the genetic resistance of egg-type chickens in response to SE inoculation, global gene expression in the spleen of 20-week-old White Leghorn was measured using the Agilent 4×44 K chicken microarray at 7 and 14days following SE inoculation (dpi). Results showed that there were 1363 genes significantly differentially expressed between inoculated and non-inoculated groups at 7 dpi (I7/N7), of which 682 were up-regulated and 681 were down-regulated genes. By contrast, 688 differentially expressed genes were observed at 14 dpi (I14/N14), of which 371 were up-regulated genes and 317 were down-regulated genes. There were 33 and 28 immune-related genes significantly differentially expressed in the comparisons of I7/N7 and I14/N14 respectively. Functional annotation revealed that several Gene Ontology (GO) terms related to immunity were significantly enriched between the inoculated and non-inoculated groups at 14 dpi but not at 7 dpi, despite a similar number of immune-related genes identified between I7/N7 and I14/N14. The immune response to SE inoculation changes with different time points following SE inoculation. The complicated interaction between the immune system and metabolism contributes to the immune responses to SE inoculation of egg-type chickens at 14 dpi at the onset of lay. GC, TNFSF8, CD86, CD274, BLB1 and BLB2 play important roles in response to SE inoculation. The results from this study will deepen the current understanding of the genetic response of the egg-type chicken to SE inoculation at the onset of egg laying.

Utilisation of snail meal as a protein supplement in poultry diets

There are several species of snail with varying nutrient profile. The protein content of snail meal (53–83 %) is comparable to or higher than fish meal. Apart from lower methionine, the essential amino acids composition of snail protein is similar to fish meal and better than soybean meal. The fat of snail meal is high in polyunsaturated fatty acids and has a good supply of essential fatty acids (linoleic, linolenic and arachidonic acids) and minerals. These qualities make the meal a suitable substitute for more expensive, conventional protein feedstuffs. The variability in nutritional content, potential presence of anti-nutritional factors (cyanide, tannins and saponins) and the seasonal availability of snails (mainly during the moist season) are major factors limiting the use of snail meal in poultry diets on a commercial scale. However, heat processed snail meal could be effectively utilised for practical on-farm feed applications to reduce cost and provide an environmentally friendly method of controlling snails, especially where they are major agricultural pests. In suitable regions, snails could be intensively bred to ensure the availability of the meal in commercial quantities for poultry feeding. Heat processed snail meal is recommended at 10% in the diet of meat and egg-type chickens but raw snail meal is not. The composition of snail meal (nutritional and anti-nutritional properties), recommendations in diets for domestic chickens, results of some feeding experiments and major constraints to its efficient utilisation are discussed in the following paper.

Effect of Alternative Housing Systems on Blood Profile of Egg-type Chickens in Humid Tropics

Effect of Alternative Housing Systems on Blood Profile of Egg-type Chickens in Humid Tropics

Mutations in and Expression of the Tumor Suppressor Gene p53 in Egg-Type Chickens Infected With Subgroup J Avian Leukosis Virus.

To investigate the molecular mechanisms of the oncogenic effects of avian leukosis virus subgroup J (ALV-J), we examined mutations in and the expression of p53 in the myelocytomas distributed in the liver, spleen, trachea, and bone marrow, as well as in fibrosarcomas in the abdominal cavity and hemangiomas in skin from chickens that were naturally or experimentally infected with ALV-J. Two types of mutations in the p53 gene were detected in myelocytomas of both the experimentally infected and the naturally infected chickens and included point mutations and deletions. Two of the point mutations have not been reported previously. Partial complementary DNA clones with a 122-bp deletion in the p53 gene ORF and a 15-bp deletion in the C-terminus were identified in the myelocytomas. In addition, moderate expression of the mutant p53 protein was detected in the myelocytomas that were distributed in the liver, trachea, spleen, and bone marrow. Mutant p53 protein was not detected in the subcutaneous hemangiomas or in the abdominal fibrosarcomas associated with natural and experimental ALV-J infection, respectively. These results identify mutations associated with abnormal expression of p53 in ALV-J-associated myelocytomas, suggesting a role in tumorigenesis.

Effect of the frizzle gene (F) on egg production and egg quality of laying hens kept in tropical villages

1. Two experiments were conducted to determine the influence of the frizzle gene (F) on the production and quality of chicken eggs kept on village farms in Ghana.2. In the first experiment, 144 pullets, 72 each of Ff and ff pullets from F1 birds, were compared in a randomised complete block design (RCBD), with three villages and 4 batches of hatch as blocks and the two feather genotypes (Ff and ff) as the treatments.3. The Ff pullets were superior (P < 0.05) to their ff counterparts in terms of the number of eggs per clutch, egg mass and hen-housed and hen-d rates of lay, whereas age at first egg was lower (P < 0.05) in ff layers compared to Ff ones.4. The eggs of the F1 heterozygous frizzle (Ff) layers had higher values for albumen height, Haugh unit and yolk height compared with eggs from their normal feathered counterparts.5. In the second experiment, 144 pullets, 48 each of FF, Ff and ff pullets, were compared in a RCBD, with three villages and 4 batches of hatch as blocks and the two feather genotypes (Ff and ff) as the treatments.6. The F2 birds with genotypes Ff and FF were better than their ff counterparts in terms of the number of eggs per clutch, egg mass, and hen-housed and hen-d rates of lay. Age at first egg was significantly lower in ff layers compared to FF and Ff ones.7. The Haugh unit value was higher in the homozygous and heterozygous frizzles compared to the normal feathered ones.8. The presence of the frizzle gene (F) in egg type chickens led to an improvement in egg production and egg quality traits in village chickens, and the cross-breeding scheme evaluated in this project could contribute to improved productivity.

Voluntary food intake variation in chickens on lysine-free diet is attributed to the plasma lysine concentration

1. Growing chickens decrease their voluntary food intake when they receive a diet deficient in a single essential amino acid. Our previous studies suggest that the decreased food intake was associated with some metabolic changes.2. In order to reveal the involvement of plasma lysine fluctuations in the reduction of food intake, we examined whether maintaining the plasma lysine concentration in chickens on a lysine-free diet (the purified diet contained no lysine) restored the food intake to that of the control (lysine hydrochloride 11.9 g/kg) group.3. Male egg-type chickens at 21 d of age were injected with lysine at doses of 0.1 g/ml one hour after presenting the lysine-free diet. This injection increased the plasma lysine concentration one hour later and kept it similar to that of the control group for the following 2 h. Chickens ate the lysine-free diet as much as the control diet when their plasma lysine concentration was kept at a similar level to the control group. Injection of saline or alanine (0.12 g, isonitrogenous to lysine 0.1 g) into the crop of chickens on the lysine-free diet did not bring about the variations of food intake and plasma lysine concentrations as observed in those with lysine.4. These findings show that the food intake variation was attributed to the plasma lysine concentration in the chickens on the lysine-free diet.

Identification and characterization of avian hepatitis E virus in 2013 outbreaks of hepatitis-splenomegaly syndrome in two US layer operations

Two commercial Midwestern egg-type chicken flocks experienced significant increases in mortality rates in April 2013 with clinical signs appearing in 17-week-old pullets on Farm A and in 46-week-old hens on Farm B. Average weekly mortality was 0.44% over a 4-week period on Farm A and 0.17% over an 8-week period on Farm B. On Farm A, flocks in the affected house had a 45% decrease in daily egg production from weeks 19 to 27 when compared with standard egg production curves (P < 0.01) while no decrease in egg production was noticed on Farm B. Post-mortem examination revealed changes consistent with hepatitis-splenomegaly syndrome, including hepatomegaly with serosanguineous fluid in the coelomic cavity and hepatic subcapsular haemorrhages. Microscopic lesions were characterized by multifocal necrotizing hepatitis and intrahepatic haemorrhage. No significant bacteria were recovered from liver samples, but 72 to 100% of the liver samples from affected chickens on Farm A (8/11) and Farm B (7/7) contained detectable amounts of avian hepatitis E virus (aHEV) RNA as determined by polymerase chain reaction. Sequencing and phylogenetic analysis of a 361-base-pair fragment of the helicase gene demonstrated 98.6 to 100% nucleotide identity between the aHEV genomes from Farm A and Farm B, whereas identities ranged from 74.6 to 90.5% when compared with other representative sequences. Sequences from this study clustered within aHEV genotype 2 previously recognized in the USA. In contrast to other reported aHEV outbreaks that occurred in 30-week-old to 80-week-old chickens, in the present investigation clinical aHEV was identified in 17-week-old chickens on one of the farms.

Fertility and hatchability characterization of three strains of egg type chickens

The fertility and hatchability characteristics of three popular strainsof egg type chickens in Nigeria, namely chickens (ISABROWN), Alpha (Improved native) and the local strain (Pure native) chickenswere studied. They were compared from twenty weeks of age using 15 hens and 3cocks from each strain. The parameters recorded were egg production, eggweight, percent fertility and hatchability. The experiment was replicated threetimes. The data obtained showed that the improved native strain produced moreeggs followed by the exotic strain and lastly, the pure native strain. ISA Brownstrain and improved native strain were similar in egg weight; but performedbetter than pure native and the other strains. The ISA Brown recorded mean eggweight of 59.27 ± 0.02, Improved native recorded mean egg weight of 53.10 ± 002 and the purenative recorded mean egg weight of 41.00 ± 0.02. Conversely, fertility was highest in the pure native strain(86.04) followed by improved native strain 83.08) and the exotic strainrecorded the least percent fertility of (68.21). Hatchability was highest inthe improved native strains with percentage hatchability of 77.33, followed bythe pure native of percentage hatchability of 73.55 and ISA Brown (exotic)recorded the least percentage hatchability of 61.24. From the findings, theimproved native did well in all the parameters investigated and has enough roomto carry out selection for improvement.

Occurrence of Aviadenovirus in chickens from the poultry industry of Minas Gerais

The occurrence of Aviadenovirus (FAdV) was investigated in chickens from the poultry industry of Minas Gerais state, Brazil. The investigation was conducted due to the scarcity of recent data in the country and its description in neighboring countries. For this purpose, livers were collected from layer chicks (n=25), older layers (n=25), broilers (n=300), and livers (n=25) and stool (n=25) samples from broiler breeders, representing the major poultry regions of the state. FAdV DNA was demonstrated using a previously described PCR protocol for amplifying part of the hexon gene encoding sequence. FAdV was found in layer chicks (36%), widespread (100%) in older layers, and with regional differences in broilers (24-86%). Although all broiler breeder stools were negative, FAdV DNA was detected in livers (16%, 4/25) of stool-negative birds. In order to obtain additional information on the circulation of the infection, livers of subsistence chickens collected from one poultry intensive region, were evaluated (n = 12), with FAdV being detected in all samples. FAdV was found in young and old layers, broilers, broiler breeders and free-range chickens, and results suggest the circulation of FAdV among different types of chickens. The detection in older layer chickens may indicate an extended risk of horizontal transmission in regions of Minas Gerais with mixed activity of egg and meat type chickens and poor biosecurity strategies. The infection in breeders may indicate vertical transmission and the continuous production of infected progenies. The hexon-gene-targeted PCR amplicon sequences aligned with FAdV of species D of Aviadenovirus. Results indicate the necessity for biosecurity, especially for breeders, separating flocks according to origin, age and health status, which will be an advantage regarding any pathogen.

Changes in Stress Indicators of Egg-Type Chickens in Response to Different Intensive Housing Systems in Humid Tropics

Welfare of the animals is of global interest recently and housing of egg-type chickens inside battery cages is being banned in many developed countries in view of the stress to which the chickens are exposed. Measurement of some blood parameters such as White blood cell (WBC) counts and differential leucocytes counts and Heterophil to lymphocyte ratio have been used to assess stress among chickens. Changes in these parameters were therefore investigated among chickens in different housing systems in a typical humid tropical region of the world where animal welfare issue is currently unpopular.108, 17-weeks old Super Black hens (SBL) and 108, 17-weeks old Super Brown hens (SBR) were randomly allotted to three different intensive housing systems of Partitioned Battery Cage (PBC), Extended Battery Cage (EBC) and Deep Litter System (DLS) in a Randomized Complete Block (RCB) design with 36 hens per housing system each with three replicates. The experiment lasted 37 weeks. Parameters measured included Total White Blood cells (WBC), Differential Leukocytes while Heterophil-Lymphocytes ratios (H/L) were calculated .Data collected were subjected to statistical analysis using 2-way ANOVA while means were separated with Duncan’s Multiple Range Test (DMRT). Housing systems had significant effect on the differential leukocyte counts and H/L ratios but not on WBC counts. Hens housed inside PBC (control) had the highest values of H/L ratio with the least values from those housed on DLS. Meanwhile, the parameters investigated were not significantly affected by the strain. Higher values of H/L ratio recorded by hens housed on PBC which is the conventional system of housing layers in the tropics are indications of stress on the chickens due to lack of freedom to move about and which is against the welfare of the chickens.

Delayed Post Hatch Feeding Affects Performance, Intestinal Morphology and Expression Pattern of Nutrient Transporter Genes in Egg Type Chickens

Effect of post-hatch (PH) feed deprivation (FD) for 6, 12, 24 and 36 hrs., on the performance, gut development and differential expression of nutrient transporter genes in egg type chickens (crosses of White Leghorn) was studied. Significant decrease (P=0.001) in yolk utilization (in all the FD chicks) and relative weight of gizzard, intestine, liver and pancreas was observed in 24 and 36 hrs FD chicks. The 36 hrs FD chicks recorded lower (P=0.001) body weight, lower feed intake and inferior FCR, decreased serum glucose, but higher cholesterol and uric acid level than the control (immediate fed group) or 6 hrs FD chicks. Villi height in duodenum, jejunum and ileum decreased (P=0.001) but villi width increased (P=0.001) with increase in FD period and significant changes were observed particularly in 24 or 36 hrs FD chicks. Relative expression of Cdx gene decreased with age of the bird and the feed restriction period. Expression of SGLT, FABP gene was not associated with the feed deprivation period, while that of EAAT3 gene increased in 24 or 36 hrs FD chicks. No difference was observed in bursa, spleen and thymus weight. In vivo humoral and cellular immune response was significantly better in chicks FD for 6, 12 and 24 hrs than control and 36 hrs FD chicks. Expression of immunity related genes IL-6 and TLR-2 increased as the FD period increased. It may concluded that PH feed deprival for first 12 hrs did not affect growth performance, intestinal morphology and immune response but feed withdrawal for 24 or 36 hrs adversely affect the intestinal morphology and few nutrient transporter genes expression in egg type chickens.

Comparison of Atrogin-1/MAFbx mRNA Expression in the Gizzards of Egg- and Meat-Type Chickens

We examined atrogin-1/MAFbx mRNA expression in the smooth muscle of gizzards from egg- and meat-type chickens. Gizzard weight relative to body weight was significantly lower in the meat-type chickens than in the egg-type at 14 d of age. In contrast, the level of atrogin-1/MAFbx mRNA in the gizzard was significantly higher in the meat-type chickens than in the egg-type chickens. Thus atrogin-1/MAFbx mRNA expression in the smooth muscle of the gizzard was higher in meat-type chickens than in egg-type chickens, in contrast to its expression in the skeletal muscles.

Expression and Methylation of FGF2, TGF-β and Their Downstream Mediators during Different Developmental Stages of Leg Muscles in Chicken

A number of growth factors determine the proliferation of myoblasts and therefore the number of ultimate myofibers. The members of transforming growth factor-beta (TGF-β) family and the fibroblast growth factor 2 (FGF2) have profound effects on skeletal myoblasts proliferation in various animal systems. To investigate their involvement in different stages of avian skeletal muscle development in vivo, we detected the mRNA expression and DNA methylation profiles of TGF-β2, TGF-β3, FGF2 and their downstream mediators in leg muscles at embryonic day 10, day of hatch and day 45 posthatch, using both Arbor Acres meat-type and White Leghorn egg-type chickens. By real-time PCR, we found that the expression levels of TGF-β2, TGF-β3, Smad3 and FGF2 were significantly (P≤0.01) higher at embryonic day 10, a developmental window of abundant fetal myoblasts expansion, by comparison to day of hatch and day 45 posthatch. The methylation status of the 5′ end region of these four genes was examined subsequently. A section of a CpG island in the 5′ end region of FGF2 was significantly hypomethylated (P≤0.01) at embryonic day 10, compared with neonatal and postnatal stages in both stocks. Our results suggested that TGF-β2, TGF-β3, Smad3 and FGF2 may play important roles in fetal myoblasts proliferation in chicken hindlimb, and the transcription of FGF2 in this wave of myogenesis could be affected by DNA methylation in 5′ flanking region. These outcomes contribute to our knowledge of the growth factors in avian myogenesis. Further investigation is needed to confirm and fully understand their functions in fetal limb myogenesis in birds.

Isolation, identification, and phylogenetic analysis of two avian leukosis virus subgroup J strains associated with hemangioma and myeloid leukosis

Cases of myeloid leukosis and hemangioma associated with avian leukosis virus subgroup J (ALV-J) are becoming more frequent in China in commercial layer chickens and breeders of egg-type chickens. In this study, two strains of ALV-J (SCAU11-H and SCAU11-XG) associated with hemangioma and myelocytoma were isolated from commercial broiler breeder animals in 2011. Their full-length proviral sequences were analyzed, revealing several unique genetic differences between the two isolates, and suggesting that the two viruses were derived from two distinct lineages. Strain SCAU11-H showed high sequence homology to early Chinese isolates associated with hemangioma, while strain SCAU11-XG was genetically closer to the prototype strain, HPRS-103. The complete genomic nucleotide sequences of SCAU11-H and SCAU11-XG were 7471 bp and 7727 bp in length, respectively. They shared 94.8% identity with each other, and had 94.0-96.8% nucleotide identity to ALV-J reference isolates. Homology analysis of the env, pol, and gag genes of the two isolates and other references strains showed that the gag and pol genes of the two viruses were more conserved than the env gene. In addition, the two isolates had significant deletions and substitutions in their 3'-UTR regions, compared to HPRS-103. These results suggest that the env gene and the 3'-UTR regions in these ALV-J isolates have evolved rapidly, and might be involved in the oncogenic spectrum of ALV-J. The results of this study contribute to our further study of the relationship between ALV integration patterns and multi-pathotypes associated with ALV-J.

Improving the Outcome of a Marek's Disease Challenge in Multiple Lines of Egg Type Chickens

A challenge test following inoculation with a standard amount of a vv+ strain of the Marek's disease (MD) virus in multiple lines and multiple generations of egg type chicken and the corresponding phenotypic trend are described. This program significantly reduced mortality of progeny from selected sires for three to 11 generations in eight of the nine elite lines studied herein. In brown egg lines, a retrospective analysis of DNA indicated an association between the blood type B (major histocompatibility complex) of the sire and the MD mortality in the challenge of its progeny. As a result of the multigeneration stock amplification and crossbreeding processes used in the commercial breeding industry, improvement in survival after challenge at the elite level will translate to improved welfare for millions of birds at the commercial production level.

Development and characterization of monoclonal antibodies to subgroup A avian leukosis virus

Avian leukosis virus subgroup A (ALV-A) is a retrovirus which infects egg-type chickens and is the main pathogen of lymphoid leukosis (LL) and myeloid leukosis (ML). In order to greatly enhance the diagnosis and treatment of clinical avian leukemia, two monoclonal antibodies (MAbs) to ALV-A were developed by fusion between SP2/0 and spleen cells from mice immunized with expressed ALV-A env-gp85 protein. Using immunofluorescence assay (IFA), two MAbs reacted with ALV-A, but not with subgroups B and J of ALV. Western blot tests showed that molecular weight of ALV-A envelope glycoprotein recognized by MAbs was about 53 kD. Isotyping test revealed that two MAbs (A5C1 and A4C8) were IgG1 isotypes. These MAbs can be used for diagnosis and epidemiology of ALV-A.

Complete Genome Sequence of an Avian Leukosis Virus Isolate Associated with Hemangioma and Myeloid Leukosis in Egg-Type and Meat-Type Chickens

Subgroup J avian leukosis virus (ALV-J) was first isolated from meat-type chickens that developed myeloid leukosis (ML). In recent years, field cases of hemangioma (HE) or HE and ML, rather than ML alone, have been reported in commercial layer flocks exposed to ALV-J with a high incidence in China. Here we report the complete genomic sequence of an ALV-J isolate that caused both HE and ML in egg-type and meat-type chickens in China. These findings will provide additional insights into the molecular characteristics in genomes, host range, and pathogenicity of ALV-J.

MORTALITY AND DISEASE STATUS IN HY-LINE AND ISA-BROWN STRAINS OF LAYER CHICKENS REARED IN CAGE SYSTEM IN BANGLADESH

Mortality and disease status in Hy-Line (n= 3450) and ISA-Brown (n = 250) strains of layer chickens were carried out in three commercial layer farms in the district of Mymensingh from day-old to 65 weeks age of birds from September 2003 to December 2004. The management including housing, hygienic measures, vaccination practices, diseases occurred and mortality were observed and recorded daily. Diseases and disorders were diagnosed based on the disease history, clinical signs, characteristics necropsy lesions, morbidity and mortality rates, and laboratory investigations including bacteriological and parasitological examinations. The morbidity and mortality of chickens caused by different diseases and disorders were statistically analyzed on the basis of farms, strains of birds, age and seasons. An overall 32.38% (n = 1198) morbidity and 21.30% (n = 788) mortality was recorded among 3700 chickens. Etiological analysis showed that the highest mortality caused by bacterial diseases (7.08%), followed by viral diseases (5.81%), fungal diseases (2.18%), mycoplasmosis (1.89%), parasitic diseases (1.83%) and nutritional and other disorders (2.48%). Specific diseases and disorders caused mortality in chickens included Salmonellosis (3.14%), Colibacillosis (2.51%), Fowl cholera (0.46%), Infectious coryza (0.41%), Necrotic enteritis (0.59%), Infectious bursal disease (2.19%), Newcastle disease (1.76%), Avian leukosis (0.73%), Fowl pox ( 0.51%), Marek’s disease (0.62%), Aspergillosis (1.54%), Aflatoxicosis (0.65%), Mycoplasmosis ( 1.89%), Ascaridiasis (0.22%), Tapeworm infection (0.16%), Coccidiosis (1.32%), Ectoparasitosis (0.14%), Nutritional deficiency (0.68%), Ascites, Hydropericardium hepatitis syndrome (0.49%), Cannibalism (0.27%), Egg peritonitis (0.22%), Egg bound disorder (0.43%) and Heat stroke and cold (0.41%). Diseases caused highest mortality during laying period (8.43%), followed by growing (6.32%), pullet stage (4.65%) and brooding (3.78%) ages. Both the morbidity and mortality rates in ISA-Brown strain (62.60% and 37.20%) were found significantly (p &lt; 0.01) higher in comparison to Hy-Line (30.17% and 20.14%) strain of chickens. Seasonal influences on mortality in layer type chickens showed significantly (p &lt; 0.01) highest mortality during summer (8.57%), followed by winter (6.51%) and rainy (6.22%) months. It may be concluded that the infectious diseases even with vaccination associated with high morbidity and mortality in commercial egg type chickens in Bangladesh.DOI = http://dx.doi.org/10.3329/bjvm.v9i1.11204 Bangl. J. Vet. Med. (2011). 9(1): 01-16