Veterinary Research Forum

Abstract Infectious bronchitis, being caused by a coronavirus, is a significant disease affecting broiler and layer chickens, leading to substantial losses in the poultry industry due to the high mortality rates and decreased egg yield. Nearly 30 serotypes and 100 variants were described to date; developed vaccines are being for some severe cases, like the Massachusetts strain, to mitigate the effects. Determining the vaccinal strain's titer is crucial for creating an effective vaccine, and calculating the virus infectivity in the egg embryo is very important using dilutions ranging from 10^-3 to 10^-8, from each dilution 0.10 mL is used. The aim of this study was to determine the effects of the avian bronchitis virus injected into the allantoic cavity of ten days old embryonated eggs. Real-time polymerase chain reaction tests determined the viral load in the allantoic fluid. The embryos were removed to study gross injuries. The trachea, lung, and mesonephros were removed and submitted for histopathological studies, and nuclear factor-kappa B immunofluorescence analysis. The results revealed that the dilution of one-thousandth of the virus in the embryos caused the highest organ damage and viral replication. Varying degrees of hyperemia, edema, cellular infiltration, and degeneration were observed in the trachea, lung, and mesonephros depending on the virus dilution. This study provides valuable insights into the pathogenesis of the avian bronchitis virus, and has a potential impact on achieving an effective vaccine.

Abstract Infectious Bronchitis (IB) is one of the most important viral diseases of poultry. It causes major financial losses in the poultry industry. It is caused by the infectious bronchitis virus (IBV). This study investigated the genetic origin and diversity of IBV by analyzing the partial S1 sequence derived from local broiler farms in different regions of Sulaimani Governorate. Detection was performed using a newly designed primer for the partial S1 gene. The present was undertaken to understand the molecular relationship between the strains across the world compared with field virus isolates by phylogenetic tree and sequences-analysis. Phylogenetic tree demonstrated that field isolate made a novel group (sul-5/17-like strain), indicating new variants. Also, field virus sequences were

Abstract This experiment was carried out to investigate the effects of different levels chromium picolinate (CrPic) and chromium nanoparticles (nano-Cr) on the performance and immune function of broilers under heat stress condition. A total of 320 Ross 308 broiler chicks (from 21 to 42 days) were assigned randomly into eight treatment groups (four replicates per treatment, and 10 chicks per replicate) and be reared at either thermoneutral (21 ˚C) or heat stress (36 ^◦C). The treatments were control (T1) group without supplementation and heat stress, T2 as a heat stress group without supplementation, T3, T4 and T5 groups which were supplemented with 500, 1000 and 1500 ppb CrPic in diet with heat stress, respectively and T6, T7 and T8 groups which were supplemented with 500, 1000 and 1500 ppb nano-chromium in diet under heat stress, respectively. Supplementation of chromium and nano-chromium improved performance including weight gain and feed conversion ratio of heat-stressed chickens. Antibody titers against avian influenza (AI) and infectious bronchitis (IB) at 21 to 42 days of age in broilers fed supplemental chromium and nano-chromium were higher than broiler chickens fed control diet (p < 0.05). Nano-chromium supplementation at level of 1000 ppb and CrPic at level of 1500 ppb improved the antibody titers against AI and IB of broilers under heat stress conditions. It can be concluded from these findings that dietary supplementation of CrPic and nano-Cr can improve performance and antibody titers against AI and IB under heat stress conditions in broilers.

Abstract Increased susceptibility of birds to avian pathogens in intensive husbandry system has emphasized on necessity of improvement of innate and specific immune responses of birds by the fast establishment of a beneficial microflora and immune stimulator factors to guarantee healthy and low-price products. During this study, 192 one-day-old broiler chicks (Ross-380) in four groups with three replicates per group were used to investigate effectiveness of synbiotic Biomin Imbo on immune responses of the chickens following routine vaccination against Newcastle disease (ND), avian influenza (AI), infectious bronchitis (IB) and infectious bursal disease (IBD). The results of this study indicated that supplementation of Biomin Imbo in diet enhanced humoral immune responses significantly in the case of ND, IB, IBD (p = 0.049, p = 0.020, p = 0.036, respectively), but insignificantly in the case of AI (p = 0.160) following vaccination of the chickens against these most common important viral poultry diseases. It was more effective following vaccination with live than killed vaccines. In conclusion, application of synbiotic Biomin Imbo, as a feed-additive adjuvant promotes acquired humoral immune responses of broiler chickens.