A Review of Veterinary and Economically Devastating Coronaviruses: Emphasising Poultry and Pigs

Coronaviruses are known can cause a significant impact on veterinary medicine and socio-economic. Understanding the biological characteristics and dynamics of pathogenic coronaviruses is a major scientific challenge with potential impacts on animal health. Coronaviruses are typically known to cause respiratory or enteric diseases in poultry and pigs. However, some coronavirus strains may cause extra-pulmonary and extra-intestinal disorders. Keeping in view the limitations of the current knowledge, the impact of coronaviruses on poultry and pigs was examined

Selection of immature bovine oocytes using Brilliant Cresyl Blue enhances nuclear maturity after vitrification

Beside cooling/warming rates and composition of vitrification solution, developmental stage of immature oocytes may also affect their vitrification outcome. The aim of the present study was to evaluate the selection effect of developmentally competent immature bovine oocytes by Brilliant Cresyl Blue (BCB) on maturity of oocytes after vitrification. Oocytes were obtained from slaughterhouse ovaries. Only oocytes with 4-5 layers of cumulus cells and homogenous cytoplasm were used. After exposure to BCB stain, immature oocytes were divided into colored (BCB+) and colorless (BCB-) cytoplasm groups. Immature oocytes were equilibrated in VS1 (7.5 Ethylene Glycol (EG)+7.5% DMSO) for 10-12 min and then exposed to VS2 (15% EG+ 15% DMSO+0.5M sucrose) for 1 min. Thereafter, oocytes were loaded on Cryotop and directly plunged into liquid nitrogen. After warming, oocytes were examined for presence of polar body and nuclear maturity. Higher number of oocytes in BCB+group extruded first polar body in comparison with other vitrified groups but not significantly (p>0.05). Compared to the BCB- oocytes, there was significantly lower percentage of degeneration for BCB+oocytes (p<0.05). Within vitrified groups, reaching to the MII stage was significantly higher in BCB+group (51.5%) compared with BCB and vitrified-control groups (27.9 and 40.3%, respectively). These results indicated that selection of potent immature bovine oocytes using brilliant cresyl blue improved the nuclear maturity of immature oocytes after vitrification. In addition, this selection can be a valuable tool to improve the vitrification outcome

Cryotop device enhances vitrification outcome of immature Bovine Oocytes.

The aim of this study was to evaluate the effectiveness of different cryodevices (Open Pulled Straw (OPS), Electron Microscopy Grid (EMG) and cryotop for vitrification of immature bovine oocytes. Polar body, MII stage, survivability and subsequent developmental rates were compared. Only oocytes with 4-5 layers of cumulus cells were used. Oocytes were equilibrated in the first vitrification solution (VS1; HS+10% DMSO+10% Ethylene Glycol (EG)) for 30-45 sec and then in the second vitrification solution (VS2; 20% DMSO+20% EG+0.5 M Sucrose) for 25 sec. Within 30 sec they were mounted on one of the cryodevices and directly plunged into Liquid Nitrogen (LN2) for 10 days. Immature oocytes vitrified using cryotop represented higher rate of polar body extrusion and nuclear maturity (p<0.05). The highest survivability resulted from cryotop and EMG groups and no significant difference found between them. Vitrified oocytes in cryotop group had highest cleavage and blastocyst rates. All of the mean measured rates for vitrified/warmed immature oocytes were significantly lower than that of control group (p<0.05). In conclusion, results of this study showed the superiority of cryotop device for vitrification of immature bovine oocytes which resulted in higher viability and subsequent embryo development

Development of sperm separation system using electrical current for bull

A novel electrophoretic separation system has been successfully applied for the preparation of human sperm prior to the execution of assisted reproductive techniques (ARTs). This new system is designed to overcome the generation of reactive oxygen species (ROS) through centrifugation in conventional sperm preparation. Since the previous study showed favorable outcomes in humans, this study intends to implement this new system for animal sperm preparation particularly in bull. Fresh semen from adult bulls were used. Optimization of the electrophoretic system for optimum bull sperm separation involved different strength of voltage and separation time. The voltages applied were 10V, 20V, 30V, 40V, 50V, and 60V. For each voltage applied, the system was operated for a duration of 12 min. An average of 10 μl fractionalized semen was taken out at the collection site at every 2-min interval. Every fractionated sperm was then evaluated for percentage of viability, motility, and DNA damage assessment. Result showed that electrophoresis at 20V and 6 min yielded more than 80% viable and more than 70% motile sperm population with the lowest DNA damage. In conclusion, the system was able to fractionate high quality bull sperm at 20V and 6 min

Molecular characterisation and pathogenicity evaluation on attenuated Malaysian strains of infectious bronchitis virus

Recent molecular epidemiology study detected local Malaysian variant (MV) and QX-like IBV strains circulating in commercial farms in Malaysia. Subsequent pathogenicity study showed these two strains are pathogenic in specific-pathogen-free (SPF) chickens. However, the efficacy study of commercially available vaccines in conferring protection against these two IBV strains in chickens and their molecular characteristics following attenuation in embryonated chickens eggs (ECE) have not been well studied. Hence, two previous characterised IBV isolates, MV IBS037A/2014 and QX-like IBS130/2015 strains were used as challenged viruses in vaccine efficacy and in virus attenuation studies. In the vaccine efficacy study, four commercially available IB vaccines strain Mass H120, K2, 1/96 and 4/91 were prepared as recommended by the respective manufacturers. SPF chickens were grouped according to the respective vaccine groups and vaccinated once via oculonasal route. At 21 day post-vaccination (dpv), the chickens were challenged with 105.0 EID50/0.1 ml of wildtype IBS037A/2014 or IBS130/2015. Results showed that all the vaccinated groups successfully induced antibody titre as detected by ELISA 3 weeks post vaccination. Following challenged, all the vaccinated groups showed different clinical signs and lesions of IB. Based on the protection results obtained, all the tested IBV vaccine strains were able to confer partial protection against IBS037A/2014 except Mass H120 vaccine that induced poor protection. However, all the tested vaccines were unable to provide protection against IBS130/2015 except for IBV vaccine strain 1/96 that able to confer partial protection. Virus neutralisation assay showed that the IBS037A/2014 has minor antigenic subtype difference with Mass H120 and 4/91 strains, whilst IBS130/2015 has minor antigenic subtype difference with K2 strain. The S1 sequence analysis showed that passage 70 attenuated IBS037A/2014 virus has 9% nucleotide and amino acid variations, while the passage 70 attenuated IBS130/2015 virus has 7% and 11% nucleotide and amino acid variations, respectively, when compared to their respective wildtype viruses. The attenuated IBS037A/2014 virus has majority of the amino acid variations in the hypervariable region (HVR) 1, followed by HVR 2 and 3. Meanwhile, the attenuated IBS130/2015 has the highest amino acid variations in the HVR 2, followed by HVR 3 and 1. The pathogenicity of the passage 70 attenuated viruses were compared with their respective wildtype viruses in SPF chickens. Significant differences in the microscopic lesions were detected in trachea (p=0.001) and kidney (p=0.022) of chickens inoculated with the attenuated IBS037A/2014, and trachea (p=0.001) of chickens inoculated with the attenuated IBS130/2015. The tracheal ciliary activity was significantly higher (p=0.001) in the attenuated IBS037A/2014 group, whilst no significant differences (p=0.062) in the attenuated IBS130/2015 group when compared to their respective wildtype viruses. Significant decreased in the virus copy numbers (VCN) were also detected in the trachea (p=0.013) and kidney (p=0.001) of chickens inoculated with the attenuated IBS037A/2014, and trachea of chickens inoculated with the attenuated IBS130/2015. However, a significantly increased in VCN were detected in the kidney (p=0.001) of chickens inoculated with the attenuated IBS130/2015 when compared to the wildtype viruses. In conclusion, the tested vaccine strains used in this study unable to induce complete protection against MV and QX-like. Meanwhile, the attenuated MV IBS037A/2014 showed reduced pathogenicity, whilst the attenuated QX-like IBS130/2015 is still pathogenic resembling the wildtype virus

A Systematic Review on the Role of the Respiratory and Intestinal Mucosal Immunity during Newcastle Disease Virus Infection

Newcastle disease (ND) is a devastating disease causing substantial economic losses due to high morbidity and mortality events worldwide in poultry. The disease is caused by the Newcastle disease virus (NDV), an enveloped, non-segmented single strand of negative-sense RNA approximately 15 kb in length. NDV can be classified as asymptomatic, lentogenic, mesogenic or velogenic pathotypes based on the levels of pathogenicity in chickens. The disease is being controlled by vaccination using either live-attenuated or inactivated vaccines. Various studies have been conducted to evaluate the association between mucosal immunity on NDV, however, the contribution of role of either respiratory or intestinal mucosal immunity remains to be revealed. Thus, the current study aimed to systematically review published articles about the role of respiratory and intestinal mucosal immunity during NDV infection. An online database search was performed through four different databases namely PubMed, Science Direct, JSTOR and Google Scholar using the following set of keywords: ‘Newcastle disease’, ‘Newcastle disease virus’, ‘respiratory’, ‘intestinal’ and ‘mucosal immunity’. Out of the 34,142 results, only 28 articles were suitable according to inclusion and exclusion criteria and were used for data extraction. Results showed that innate immunity was the most affected parameter when exposed to NDV infections, however, the role of respiratory and intestinal mucosal immunity against NDV infection remains widely uncharted. In conclusion, the role of the sub-components of respiratory and intestinal mucosal immunity toward NDV infection may become one of the determinant factors of protection for the chickens.

Evaluation of the antigen relatedness and efficacy of a single vaccination with different infectious bronchitis virus strains against a challenge with Malaysian variant and QX-like IBV strains

Background: The predominant infectious bronchitis virus (IBV) strains detected in chickens in Malaysia are the Malaysian variant (MV) and QX-like, which are associated with respiratory distress, nephropathy, and high mortality. On the other hand, the antigenic relatedness and efficacy of IBV vaccines against these 2 field IBV strains are not well characterized. Objectives: This study aimed to determine the antigen relatedness and efficacy of different IB vaccine strains against a challenge with MV and QX-like strains. Methods: The antigen relatedness and the ability of different IB vaccine strains in conferring protection against MV and QX-like were assessed based on the clinical signs, macroscopic lesions, and ciliary activity. Results: The MV strain IBS037A/2014 showed minor antigenic subtype differences with the vaccine virus Mass H120 and 4/91 strains but showed major antigenic subtype differences with the K2 strain. The Malaysian QX-like strain IBS130/2015 showed major antigenic subtype differences with the MV strain IBS037A/2014 and the vaccine strains except for K2. Chickens vaccinated once with Mass (H120) or with non-Mass (4/91 and K2) developed antibody responses with the highest antibody titer detected in the groups vaccinated with H120 and 4/91. The mean ciliary activities of the vaccinated chickens were between 56 to 59% and 48 to 52% in chickens challenged with IBS037A/2014 and IBS130/2015, respectively. The vaccinated and challenged birds showed mild to severe lesions in the lungs and kidneys. Conclusions: Despite the minor antigenic subtype differences, a single inoculation with Mass or non-Mass vaccines could not protect against the MV IBS037A/2014 and QX-like IBS130/2015

Characterization of S1 gene sequence variations of attenuated QX-like and variant infectious bronchitis virus strains and the pathogenicity of the viruses in specific-pathogen-free chickens

Besides the vaccine strains, the Malaysian variant (MV) and QX-like are the predominant IBVs detected on commercial poultry farms. These two virus strains are distinct based on genomic and pathogenicity studies. In this study, we determined the sequence of the S1 gene and compared the pathogenicity of serial passage 70 (P70) of Malaysian QX-like (QX/P70) and MV (MV/P70) strains with that of their respective wild-type viruses. The nucleotide and amino acid sequences of the complete S1 genes of QX/P70 and MV/P70 showed 1.4 to 1.6% and 3.0 to 3.3% variation, respectively, when compared to the wild-type virus. Most of the mutations were insertions and substitutions in the hypervariable regions (HVRs), primarily in HVR 3. Furthermore, selection pressure analysis showed that both viruses are under purifying selection. A pathogenicity study in specific-pathogen-free (SPF) chickens showed a reduction in respiratory and kidney lesions in chickens inoculated with MV/P70, but not with QX/P70, when compared to the respective wild-type viruses. However, MV/P70 is still pathogenic and can cause ciliary damage. In conclusion, the MV IBV strain is more responsive than the QX-like IBV strain following the attenuation process used for the development of a live attenuated IBV vaccine

Sequence analysis of S1 gene of Malaysian infectious bronchitis virus variant and QX-like strains following serial passage in specific-pathogen-free embryonated chicken eggs

Infectious bronchitis virus (IBV) causes infectious bronchitis (IB) disease in chickens is primarily a disease associated with respiratory tract. However, depending on virus strains, IBV can also infect the gut, reproductive and kidney of chickens. Controlling the disease is problematic because of the presence of diverse serotypes and strains, and poor cross-protection against different serotypes/strains. Recently, we have characterized the IBV strains circulating in Malaysia. Two of the prevalent strains, Malaysian local variant (MLV) (IBS037A/2014) and QX-like (IBS130/2015) were attenuated by serial passage of the virus in SPF embryonated chicken eggs. The virus strains at different passages were characterized based on sequence analysis of the partial S1 gene. Overall, IBS130/2015 showed a higher number of nucleotide and amino acid variations compared to IBS037A/2014 following serial passage in embryonated chicken eggs