This study was carried out on serum samples collected from broiler breeder chicken flocks vaccinated with avian influenza (AI) H5N1 inactivated vaccine. These flocks included 23 flocks aged 13 to 47 weeks reared in close houses in 7 sites; two vaccinated breeder flocks for HI antibody monitoring by 5 weeks interval samples and 8 flocks aged 41 weeks reared in different sites with identified females and males samples. The vaccine was used in a dose of 0.2 ml at 1 day in hatchery and revaccinated with 0.5 ml at age of 18 days, 19- 20 weeks and 40 weeks. Hemagglutination inhibition (HI) test was carried out against homologous antigen. The study pointed out that AI H5N1 inactivated vaccine under field application induced irregular and low HI titres following the 1st two doses ranged from log 2 0.0 to 4.15 with great variation between flocks, where samples with titre 0-2 ranged from 20 to 100%. The 3rd dose at 19-20 weeks was essential to elevate HI titres 3.25 to 7.44 with more homogenizes flock immunity and lower percentage of titres 0-2 ( 0-20 %) and as measured by HI test. Revaccination of layer flocks at 40 weeks (fourth dose) improves flock immunity facing stress of egg production as evaluated by HI (5.52 - 6.33) and lower negative percentage (5.5-11.7%). Monitoring of breeder flock every 5 weeks is essential to detect proper time of revaccination as each flock has its HI antibody curve. There was a difference in HI tit re rang log 2 0.33 to 1.2 between male and female chicks reared in the same house, but this variation not affecting flock mean. Birds at aged 41 weeks having titres < log2 3 (Seronegative) were protected when exposed to contact with infected flock as showed no clinical signs or change in HI titres after 12 days. In conclusion the usage of homologous inactivated H5N1 vaccine in 4 doses in layer flocks was of value in improving chicken immunity to AI H5N1 wild strain circulate in our field

The effect of 10 times (10x) overdose of enrofloxacin was studied in broiler chickens. One hundred and eighty chicks were classified in 3 equal groups. The first group received normal theurapeutic dose of enrofloxacin (1x) in drinking water for the first 5 consecutive days of age and repeated again at 24th -28th day of age. The second group received 10x (overdose) at the same ages. The third group was left non-medicated as a control group. Blood samples were taken on the 6th, 14th, 29th and 34th day of age for different laboratory tests. Enrofloxacin at 10x caused a decrease in the value of the following parameters: HI antibody titers to NDV vaccine at the 14th and the 34th day of age, serum albumin at the 10th day of age, hemoglobin at the 29th and the 34th day, lymphocytic count and IBDV ELISA titers at 29th day of age, uric acid at 29th day, phagocytic activity at 34th day, Lactobacillus spp. count in duodenum, feed conversion efficiency and body weight gain. The 10x (overdose) increased serum urea and creatinine at 29th day of age, serum AST and ALT at 29th and 34th day of age, and heterophilic count. Histopathological degeneration in liver, spleen, kidneys, bursa of Fabricius and thymus were demonstrated by 10x (overdose) of enrofloxacin. Challenge with vNDV caused 66.6% mortality in birds received the 10x (overdose) compared with 33.3% in the vaccinated non treated control group.

This study was done to evaluate susceptibility, protective titer level of maternal derived antibodies(MDAbs) of different chicken breed against virulent Infectious bursal disease virus (IBDV) local isolate Fy97 and prediction the optimal time for vacction. All breeds were experimentally infected orally with IBDV isolate Fy97 every 5 days following detection of MDAbs by ELISA. Clinical signs, mortality, lesions and Bursal Histopathology and lesion score were taken as criteria for comparison. Morbidity rates were observed as ≥ 30% in Fayoumi and Dandrawi infected at 15 days of age and in Senawi and Baladi and Lohmann at 20 days of age All breeds showed clinical sings of infection at 30-35 days of age where Senawi breed showed the highest values (65and 70%) followed by Fayoumi (55 and 55%), Dandrawi (50%), Baladi (55-45%) and Lohmann (50-45%). Mortality rates due to IBD infection varied from 0 to 35% in respective to age, in Fayoumi and Lohmann breeds where maximum 35 and 40% occurred at 30 day of age; respectively .Mortality in Dandrawi and Senawi varied from 5 to 40% and pass in close manner at all intervals with the highest value at 30 days of age while Baladi chicks showed same values but lower only at 20 and 25 days. Mean lesion scores in Fayoumi were the lowest at all intervals followed by Lohmann, Senawi, Baladi and Dandrawi. Results of ELISA titers at time of infection showed that Senawi chicks having the highest titers followed by Lohmann, Baladi, Dandrawi and Fayoumi at most intervals. So it necessitates more clarification of the causes of these phenomena and the role of genetics in protection against IBDV infection.

Health, religious, and commercial aspects justify the need for meat species identification. The lack of officially approved methods prompts the undertaking of research on validation of isoelectric focusing of proteins (IEF) for official purposes. Samples were prepared from pigs (Sus scrofa ferus domestica), cattle (Bos taurus), and poultry (Gallus gallus domesticus). Meat mixtures were made by blending 50%, 25%, 10%, 5%, 4%, 3%, 2%, 1%, 0.5%, or 0.2% meat of other species. Samples were examined on ultrathin polyacrylamide gels with pH 3–9 gradient. The results of the study confirmed the stable and reproducible pattern of meat protein bands. The detection limit of raw meat admixtures from pigs, cattle, and poultry mostly ranged from 2% down to 0.2% (0.2% for poultry). However, the IEF method can be used to detect the addition of pig meat to bovine meat in an amount higher than 3%. At the significant mixture level (i.e at least 5% addition of meat of another species) IEF proves itself with 100% specificity, sensitivity, and accuracy. The achieved detection limits provide a basis for recommending the IEF method for routine tests in laboratories detecting the species origin of meat.

Coronaviruses (CoVs) are a large group of enveloped viruses with a single-strand RNA genome, which continuously circulate in mammals and birds and pose a threat to livestock, companion animals, and humans. CoVs harboured by avian species are classified to the genera gamma- and deltacoronaviruses. Within the gamma-CoVs the main representative is avian coronavirus, a taxonomic name which includes the highly contagious infectious bronchitis viruses (IBVs) in chickens and similar viruses infecting other domestic birds such as turkeys, guinea fowls, or quails. Additionally, IBVs have been detected in healthy wild birds, demonstrating that they may act as the vector between domestic and free-living birds. Moreover, CoVs other than IBVs, are identified in wild birds, which suggests that wild birds play a key role in the epidemiology of other gammaCoVs and deltaCoVs. Development of molecular techniques has significantly improved knowledge of the prevalence of CoVs in avian species. The methods adopted in monitoring studies of CoVs in different avian species are mainly based on detection of conservative regions within the viral replicase, nucleocapsid genes, and 3’UTR or 5’UTR. The purpose of this review is to summarise recent discoveries in the areas of epidemiology and diagnosis of CoVs in avian species and to understand the role of wild birds in the virus distribution.

Avian reticuloendotheliosis (RE) represents an important immunosuppressive disease of poultry. The occurrence of RE in both chickens and turkeys has an immunosuppressive effect and may lead to vaccination failures. Avian reticuloendotheliosis virus (REV) is widely distributed in different kinds of birds, causing subclinical infections. Another important issue adhering to this disease is contamination of vaccines against fowl pox (FP) and Marek’s disease (MD) with REV. The capability of REV to integrate into the genome of other larger DNA viruses complicates its diagnosis and prevention. There are no efficient vaccines against RE nor treatment, which also complicates how to limit its impact on poultry farming. This paper reviews the current state of knowledge of this important immunosuppressive agent of poultry emphasising the importance of this problem in terms of diagnosis of RE.

Introduction: Highly pathogenic Asian H5-subtype avian influenza viruses have been found in poultry and wild birds worldwide since they were first detected in southern China in 1996. Extensive control efforts have not eradicated them. Vaccination prevents such viruses infecting poultry and reduces the number lost to compulsory slaughter. The study showed the efficacy of inactivated H5 vaccine from the H5N8 virus against highly pathogenic H5N8 and H5N6 avian influenza viruses in chickens. Material and Methods: Reverse genetics constructed an H5 vaccine virus using the HA gene of the 2014 H5N8 avian influenza virus and the rest of the genes from A/PR/8/34 (H1N1). The vaccine viruses were grown in fertilised eggs, partially purified through a sucrose gradient, and inactivated with formalin. Chickens were immunised i.m. with 1 µg of oil-adjuvanted inactivated H5 antigens. Results: Single dose H5 vaccine recipients were completely protected from lethal infections by homologous H5N8 avian influenza virus and shed no virus from the respiratory or intestinal tracts but were not protected from lethal infections by heterologous H5N6. When chickens were immunised with two doses and challenged with homologous H5N8 or heterologous H5N6, all survived and shed no virus. Conclusion: Our results indicate that two-dose immunisations of chickens with H5 antigens with oil adjuvant are needed to provide broad protection against different highly pathogenic H5 avian influenza viruses.

The H9N2 strains of avian influenza viruses (AIVs) circulate worldwide in poultry and cause sporadic infection in humans. To better understand the evolution of these viruses while circulating in poultry, an H9N2 chicken isolate was passaged 19 times in chickens via aerosol inoculation. Whole-genome sequencing showed that the viruses from the initial stock and those after the 8th and 19th passages (P0, P8, and P19) all had the same monobasic cleavage site in the hemagglutinin (HA), typical for viruses of low pathogenicity. However, at position 226 of the HA protein the ratio of glutamine (which favors avian-type receptor binding) to leucine (which favors mammalian-type receptor binding) decreased from 54:46 in P0, to 87:13 in P8, and then 0:100 in P19. In chickens exposed to aerosols of P0, P8, or P19, replication of the viruses was similar and mainly limited to the respiratory tract. None of the infected chickens showed any clinical signs. Over the 19 passages the viruses maintained relatively stable infectivity but gradually lost lethality to chicken embryos. According to the hemagglutination inactivation assay, P8 was slightly and P19 significantly (P < 0.05) less thermostable than P0. Collectively, after 19 passages in chickens the H9N2 AIVs retained low pathogenicity with a positive selection of L226 in the HA. These findings suggest that H9N2 viruses might acquire mammalian specificity after asymptomatic circulation in avian species.

The occurrence of veterinary drug residues in chicken meat originating from 320 small and medium scale chicken slaughterhouses in Peninsular Malaysia was determined. 637 chicken meat samples were examined for tetracycline (TCs), sulphonamide (SAs) and quinolone residues using a microbiological inhibition test and was further confirmed using liquid chromatography mass spectrometry (LCMS/MS). The presence of TC residues were confirmed in 10 (1.6%) samples, and 1 (0.2%)sample was confirmed in compliance to the established maximum residue limit (MRL) for residues of quinolone. A total of 6 (0.9%) samples were above the MRL for TC. The samples were from Pulau Pinang, Terengganu and Kelantan. Among those tested in compliance, the main analytes found for TC and quinolone werechlortetracyclines (CTC), enrofloxacin and mixture of chlortetracycline (CTC) and oxytetracycline (OTC). No samples were found to contain sulfonamides residues.

Colistin is one of the last-resort antibiotics for the treatment of multidrug-resistant infections in humans, but transmissible colistin-resistance genes have emerged in bacteria from animals. The rapid and sensitive detection among animals of colonization with bacteria carrying these genes is critical in helping to control further spread. Here we describe a method for broth enrichment of colistin-resistant Escherichia coli from animal fecal and cecal samples followed by real-time polymerase chain reaction (PCR) for the simultaneous detection of two of the main colistin-resistance genes, mcr-1 and mcr-2. The PCR uses a single set of nondegenerative primers, and mcr variants can be differentiated by melt-curve analysis. Overnight culture enrichment was effective for amplifying colistin-resistant E. coli, even when initially present in numbers as low as 10 bacteria per gram of sample. The mcr-1 and mcr-2 genes were not found in any of the Ontario swine and poultry samples investigated.