Propagation and Molecular Characterization of Fowl Adenovirus Serotype 8b Isolates in Chicken Embryo Liver Cells Adapted on Cytodex™ 1 Microcarrier Using Stirred Tank Bioreactor

Attenuation and molecular characterization of fowl adenovirus 8b propagated in a bioreactor and its immunogenicity, efficacy, and virus shedding in broiler chickens

Background and Aim

Live-attenuated vaccines are the most successful type of vaccine and could be useful in controlling fowl adenovirus (FAdV) 8b infection. This study aimed to attenuate, molecularly characterize, and determine the immunogenicity, efficacy, and challenge virus shedding in broiler chickens.

Materials and Methods

The FAdV 8b isolate (UPM08136) was passaged onto chicken embryo liver (CEL) cells until attenuation. We sequenced and analyzed the hexon and fiber genes of the passage isolates. The attenuated bioreactor-passage isolate was inoculated into 1-day-old broiler chickens with (attenuated and inactivated) and without booster groups and challenged. Body weight (BW), liver weight (LW), liver: body weight ratio (LBR), FAdV antibody titers, T-lymphocyte subpopulation in the liver, spleen, and thymus, and challenge virus load and shedding were measured.

Results

Typical cytopathic effects with novel genetic changes on CEL cells were observed. The uninoculated control-challenged (UCC) group had significantly lower BW and higher LW and LBR than the inoculated groups. A significantly higher FAdV antibody titer was observed in the challenged non-booster and attenuated booster groups than in the UCC group. T cells in the spleen and thymus of the liver of inoculated chickens were higher than uninoculated control group levels at all-time points and at different times. A significantly higher FAdV challenge virus load was observed in the liver and shedding in the cloaca of UCC chickens than in non-booster chickens.

Conclusion

The FAdV 8b isolate was successfully attenuated, safe, and immunogenic. It reduces virus shedding and is effective and recommended as a vaccine against FAdV infection in broiler chickens.

Efficacy, humoral, and cell-mediated immune response of inactivated fowl adenovirus 8b propagated in chicken embryo liver cells using bioreactor in broiler chickens

Background and Aim

Fowl adenovirus (FAdV) 8b causes inclusion body hepatitis, resulting in major economic losses globally among chickens. The objectives were to inactivate FAdV 8b isolate propagated in chicken embryo liver (CEL) cells using a stirred tank bioreactor (UPM08136P5B1) and determine the humoral and cell-mediated immune response, efficacy, and virus shedding in broiler chickens.

Materials and Methods

The FAdV 8b isolate UPM08136P5B1 was inactivated using binary ethyleneimine, adjuvanted with Montanide 71VG, inoculated into day-old broiler chickens in a booster group (BG) and non-booster group (NBG), and challenged with a pathogenic FAdV 8b strain. Clinical signs, gross lesions, body weight (BW), liver: body weight ratio, FAdV antibody titer using enzyme-linked immunosorbent assay, and histopathological changes were recorded. The CD3+, CD4+, and CD8+ T-lymphocyte profiles of the liver, spleen, and thymus using flow cytometry, and viral load in liver and cloacal shedding using quantitative polymerase chain reaction were evaluated.

Results

Chickens in the challenged control group (CCG) exhibited mild clinical signs, gross lesions, and histopathological changes, which were absent in the inoculated groups, and had lower BW and higher liver BW ratio than chickens in the unchallenged control group (UCG); BG and NBG on 35- and 42-days post-inoculation (DPI). Chickens in NBG and BG had higher antibodies than UCG on 7, 21, 35, and 42 DPI. The challenged BG and NBG produced higher antibodies than the CCG on 35 DPI. T-lymphocytes were higher among the inoculated groups than UCG in the liver, spleen, and thymus. Inoculated challenged groups recorded higher CD3+, CD4+, and CD8+ T-lymphocytes on 35 and 42 DPI than CCG. The challenged control group had a significantly higher viral load in the liver than challenged that in BG on 35 DPI and BG and NBG on 42 DPI. The challenged control group had significantly higher challenge FAdV shedding than challenged inoculated groups on 35 and NBG on 42 DPI.

Conclusion

UPM08136P5B1 was successfully inactivated and mixed with Montanide 71VG. The inactivated vaccine candidate that induced humoral and cellular immunity was effective, reduced FAdV load in the liver, and shedding in the cloaca, and could be useful against FAdV 8b infections in chickens.

Special Issue on “Bioreactor System: Design, Modeling and Continuous Production Process”

Biochemical engineering deals with the processing of biological or chemical materials using enzymes or living cells as biological catalysts [...]

Review of technology and materials for the development of cultured meat

Cultured meat production technology suggested that can solve the problems of traditional meat production such as inadequate breeding environment, wastewater, methane gas generation, and animal ethics issues. Complementing cultured meat production methods, sales and safety concerns will make the use of cultured meat technology easier. This review contextualizes the commercialization status of cultured meat and the latest technologies and challenges associated with its production. Investigation was conducted on materials and basic cell culture technique for cultured meat culture is presented. The development of optimal cultured meat technology through these studies will be an innovative leap in food technology. The process of obtaining cells from animal muscle, culturing cells, and growing cells into meat are the basic processes of cultured meat production. The substances needed to production of cultured meat were antibiotics, digestive enzymes, basal media, serum or growth factors. Although muscle cells have been produced closer to meat due to the application of scaffolds materials and 3 D printing technology, still a limit to reducing production costs enough to be used as foods. In addition, developing edible materials is also a challenge because the materials used to produce cultured meat are still not suitable for food sources.