Comparison of HVT-ND recombinant and convection-based Newcastle disease vaccination programs in the protection against the genotype VII NDV challenges: an experimental study.

Newcastle disease virus (NDV) belongs to the Avulavirus genus and Paramyxoviridae family virus that causes acute, highly infectious Newcastle disease in poultry. The two proteins of haemagglutinin neuraminidase (HN) and fusion (F) are key virulence factors with an important role in its immunogenicity. Genotype VII NDV is still among the most serious viral hazards to the poultry industry worldwide. In this study, a commercial vector vaccine (HVT-NDV) was evaluated compared to the conventional vaccination strategy against Iranian genotype VII. This experiment showed that the group receiving the conventional vaccination strategy had higher antibodies, fewer clinical signs, and lower viral loads in tracheal swabs and feces. Also, two vaccine groups showed significant difference, which could have resulted from two extra vaccine doses in the conventional group. However, except for antibody levels in commercial chickens in the Iran new-generation vaccine, this difference was minor. Further, both groups showed 100% protection in the challenge study. Despite the phylogenetic gap between the NDV-F gene placed in the vector vaccine and the challenge virus (genotypes I and VII, respectively), the rHVT-NDV vaccine offered strong clinical protection and decreased challenge virus shedding considerably.

Epidemiology of Avian Infectious Bronchitis Virus Genotypes in Iran (2010-2014).

Infectious bronchitis virus (IBV) in vaccinated chicken flocks continues to cause enormous economic losses to the poultry industry in Iran. A molecular surveillance of IBV genotypes involved in outbreaks of disease was performed. Specimens of trachea, kidney, and cecal tonsil were collected from 250 suspected flocks (more than 2500 samples) and identified between 2010 and 2014. Partial spike glycoprotein gene sequences revealed seven distinct genotypes, including Mass, 793/B, IS720, Variant 2, QX, IR-I, and IR-II, to be circulating in the chicken farms. The majority of flocks (67.6%) experienced infection with an IBV variant unrelated to the vaccine strains. These variants displayed homologies ranging from 54.1% to 78.5% and from 53% to 86% with H120 and 4/91, respectively. These findings reveal the existence of IBV variants genetically different from the vaccine strains currently in use and explain the outbreaks of disease observed in the field. The current work constitutes the first comprehensive survey of IBV in Iran and emphasizes the need for continuous monitoring and rethinking of current preventative measures.

Sequence and phylogenetic analysis of neuraminidase genes of H9N2 avian influenza viruses isolated from commercial broiler chicken in Iran (2008 and 2009).

A total of 512 tissue samples collected from 30 farms located in various states of Iran during 2008-2009 as part of a program to monitor avian influenza viruses (AIVs) infection in Iran's poultry population. To determine the genetic relationship of Iranian viruses, neuraminidase (NA) genes from ten isolates of H9N2 viruses isolated from commercial chickens in Iran during 2008-2009 were amplified and sequenced. The viruses' neuraminidase gene was >90% similar to those of A/Quail/Hong Kong/G1/97 (H9N2) sublineage. The neuraminidase stalk regions in these Viruses had no deletion as compared to that of chicken/Beijing/1/94 sublineage (Beijing-like viruses) and the two human isolates A/HK/1073/99, A/HK/1074/99. Phylogenetic analysis of neuraminidase (NA) gene showed that it shares a common ancestor A/Quail/Hong Kong/G1/97 isolate which had contributed the internal genes of the H5N1 virus. The results of this study indicated that No (Beijing-like) virus and (Korean-like) virus were found in chickens in Iran, and the NA genes of H9N2 influenza viruses circulating in Iran during the past years were well conserved and the earlier Iranian isolates may be considered to represent such a progenitor.

Molecular detection and phylogenetic analysis of Mycoplasma gallisepticum from backyard and commercial turkey flocks in Iran.

Mycoplasma gallisepticum (MG) is economically important pathogen of poultry causes airsacculitis and frequently infraorbital sinusitis in turkeys. Infections may remain without clinical signs, but they can make birds susceptible to secondary infections. This study was carried out for molecular detection and phylogenetic analysis of MG infections in commercial and backyard turkey flocks in some parts of Iran. A total number of 600 swab samples were collected from 18 commercial and 31 backyard turkey flocks. The PCR technique was performed for detecting 16S rRNA gene in the samples. Positive sample were subjected for sequencing of mgc2 gene. The results showed that 48.38% of backyard and 16.66% of commercial farms were positive for MG. These findings suggested the presence of MG in the commercial and backyard turkeys' farms of Iran. The molecular analysis indicated high sequence similarity between some Iranian turkeys isolates with Indian and Pakistanian MG isolates. Furthermore, substitutions of MG nucleic acids and correlated amino acids sequences may lead to some antigenic modifications.

Methylamine induced hypophagia is mediated via dopamine D1 and D2 receptors in neonatal meat chicks.

Recently, methylamine has been found as an endogenous amine, which is controlling food intake in mammals. However, there is no evidence about the effect of methylamine on feeding behavior in poultry. So, the present study was designed to evaluate the effect of intracerebroventricular (ICV) injection of methylamine and involvement of central methylamine/dopaminergic systems on feeding behavior in neonatal meat type chicks. In experiment 1, chicks were ICV injected with different doses of methylamine (0.48, 0.96, 1.44, 1.92 and 2.40 µmol). In experiment 2, chicks received a dose of either the control solution, 2.40 µmol methylamine, 125 nmol L-DOPA (dopamine precursor) or a combination of methylamine plus L-DOPA. Experiments 3-7 were similar to experiment 2 except that 150 nmol 6-OHDA (dopamine synthase inhibitor), 5 nmol SCH23390 (D1 receptor antagonist), 5 nmol AMI-193 (D2 receptor antagonist), 6.4 nmol NGB2904 (D3 receptor antagonist) and 6 nmol L-741, 742 (D4 receptor antagonist) were used instead of 125 nmol L-DOPA, respectively. Cumulative food intake was determined until 2 h post-injection. According to the results, methylamine significantly decreased food intake in a dose dependent manner (p < 0.05). The inhibitory effect of methylamine on food intake was significantly attenuated by 6-OHDA, SCH23390 and AMI-193 (P < 0.05), but NGB2904 and L-741, 742 had no effect on food intake induced by methylamine. In addition, hypophagic effect of methylamine significantly amplified by L-DOPA (P < 0.05). These results suggest that methylamine decrease food intake and there is an interaction between methylamine and dopaminergic system via D1 and D2 receptors in chickens.

Isolation of atypical enteropathogenic and shiga toxin encoding Escherichia coli strains from poultry in Tehran, Iran.

AIM: The purpose of this study was to investigate the prevalence of enteropathogenic Escherichia coli (EPEC) and shiga toxin producing E. coli (STEC) strains in healthy broilers in Iran. BACKGROUND: STEC and EPEC strains as diarrheagenic E. coli are among the most prevalent causative agents in acute diarrhea. Domestic animals, mainly cattle and sheep, have been implicated as the principal reservoirs of these pathotypes; however their prevalence among the broilers is varied among different countries. PATIENTS AND METHODS: A total of 500 cloacal swab samples from broilers of five different poultry houses (A-E) were collected to investigate the presence of stx1, stx2, hly, eae, and bfp virulence genes among the E. coli isolates by polymerase chain reaction. The shiga toxin encoding strains were evaluated serologically to detect their interaction with a commercial antiserum against O157 antigen. RESULTS: Out of the 500 collected samples, 444 E. coli strains were isolated. Three strains (0.67%) presented at least one of the studied virulence genes (stx2, hly and eae), two strains were identified as STEC (stx2 (+), O157:nonH7) and one as an atypical EPEC strains (eae (+) bfp (-)). CONCLUSION: The study established the presence of STEC and atypical EPEC in healthy broilers in Iran. Poultry might serve as vectors for transmission of pathogenic E. coli to human populations.

Role of cannabinoidergic system on food intake in neonatal layer-type chicken.

Central regulatory mechanisms for neurotransmitters of food intake vary among animals. Endocannabinoids have crucial role on central food intake regulation in mammals but its role has not been studied in layer-type chicken. Thus, in this study 6 experiments designed to evaluate effects of intracerebroventricular (ICV) administration of 2-AG (2-Arachidonoylglycerol, selective CB1 receptors agonist), SR141716A (selective CB1 receptors antagonist), JWH015 (selective CB2 receptors agonist), AM630 (selective CB2 receptors antagonist) on feeding behavior in 3 h food deprived neonatal layer-type chickens. In experiment 1, birds ICV injected with control solution and 2-AG (0.25, 0.5 and 1 µg). In experiment 2: control solution, SR141716A (6.25, 12.5 and 25 µg) were ICV injected to birds. In experiment 3 animals received: control solution, SR141716A (6.25 µg), 2-AG (1 µg) and co-injection of SR141716A+2-AG. In experiment 4, chickens received control solution and JWH015 (6.25, 12.5 and 25 µg). In experiment 5, control solution and AM630 (1.25, 2.5 and 5 µg) were injected. In experiment 6, the birds received control solution, AM630 (1.25 µg), JWH015 (25 µg) and co-administration of AM630+JWH015. Then, cumulative food intake was recorded until 120 min after injection. According to the results, 2-AG dose dependently increased cumulative food intake while SR141716A reduced appetite compared to control group (P < 0.05). Injection of 2-AG (1 µg) amplified food intake and its effect minimized by SR141716A (6.25 µg) (P < 0.05). Also, ICV injection of JWH015 (25 µg) dose dependently increased food intake and co-injection of JWH015+AM630 decreased JWH015-induced food intake (P < 0.05). These results suggest CB1 and CB2 receptors have an important role on ingestive behavior in FD3 neonatal layer-type chicken.