| This study investigated blood clinical pathology, the relationships between the impairment of liver-kidney and viral load after embryonic chickens infected with nephropathogenic infectious bronchitis virus. Simultaneously, with different strains of IBV infection embryonic chickens to study the effect of UA metabolism to partially elucidate the pathogenesis of NIBV provide a theoretical basis.Experiment one: A total of 120 embryonated SPF chicken eggs were used in this experiment. The eggs were randomly divided into virus and control groups of 60 eggs each(3 replicates per treatment and 20 chicken eggs per replicate). Based on the embryo median lethal dose(ELD50), each egg(13-day-old) in the virus group was challenged with NIBV at a dose of 105.5 ELD50(0.2 mL) via the allantoic cavity route. Simultaneously, the eggs in the control group were infected with sterile saline solution(0.2 mL per chicken egg) via the same route. Venous blood collected by allantoic membrane and separated plasma at three sampling time points(1, 3, 5 dpi). And the chicken embryo allantoic fluid, liver and kidney tissues were collected. The chicken embryo growth performance, plasma electrolyte,liver and kidney function, plasma antioxidant function, uric acid indexes, and viral load in liver and kidney tissue were measured, respectively. The experiment results are as follows:1. Compared with control group, the EE ratio in the virus group was significantly lower(P<0.05), the AFI values was significantly increased(P<0.05 or P<0.01), the HSI and KSI values was significantly increased(P<0.05).2. Compared with control group, the plasma concentrations of Ca2+, P+, Na+ and K+were significantly increased(P<0.05 or P<0.01) in the virus group at 3 dpi, the plasma concentrations of Ca2+, P+ and K+ were significantly increased(P<0.05 or P<0.01) at 5 dpi.3. Compared with control group, the CR, BUN and UA values in the virus group were significantly increased(P<0.05 or P<0.01), the ALT, AST, ALP and GGT activity in the virus group were significantly increased(P<0.05 or P<0.01), and the concentrations of TP,ALB and GLB in the virus group were significantly decreased(P<0.05 or P<0.01).4. Compared with control group, the concentration of MDA in the virus group was significantly increased(P<0.01), the XOD activity was significantly increased(P<0.01),the SOD and T-AOC activity were significantly decreased(P<0.05 or P<0.01), the UA levels in allantoic fluid was significantly increased(P<0.05 or P<0.01)5. In the virus group, the virus was detected in the livers and kidneys at 1, 3 and 5 dpi,the liver and kidney viral loads in the virus group peaked at 3 dpi, and the viral load in the kidney was significantly greater than that in the liver.Experiment two: A total of 180 embryonated SPF chicken eggs were used in this experiment. The eggs were randomly divided into N-IBV group, B-IBV group and controlgroups, chicken embryo challenge(B-IBV group challenged with B-IBV at a dose of 106.3ELD50) and blood sampling was same to experiment one, collected chicken embryo allantoic fluid, determination of plasma biochemical index, UA in plasma and allantoic fluid of chicken embryos. The experiment results are as follows:1. Compared with control group, N-IBV and B-IBV group can cause kidney damage,and N-IBV group indicated more severe injure.2. Compared with control group, UA values in the B-IBV group was no significant difference(P﹥0.05), and in the N-IBV group was significantly increased(P<0.01), and in the N-IBV group, UA concentration and excretion amount in the allantoic fluid were significantly increased(P<0.05 or P<0.01).In conclusion, the analysis of different types of IBV infected chicken embryo revealed the pathogenesis of NIBV. The chicken embryo challenged with NIBV decreased the body weight and induced liver and kidney damage, allantoic fluid increased, antioxidant function decline. Infection of NIBV in chicken embryo resulted in hyperuricemia and UA increased in allantoic fluid. |
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