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Vaccines are widely used to prevent Newcastle disease virus (NDV). Under the pressure of immunization, NDVs with mutations among epitopes of F and HN protein were isolated, which indicates that the efficiency of vaccine may decrease in terms of preventing emerged NDV. However, the lack of evidences to support whether these mutations contribute to antigenic mutation and immune escape in NDV leading to the controversy that the matched vaccine is more effective than the mismatched vaccine. In this study, a genotype VII velogenic NDV strain (C22) was isolated from a vaccinated farm in Tibet, China. We found that this strain was close to NDV from east China, but it had a specific mutation (K138R) in one epitope ( 131 DYIGGIGKE 139 ) of HN protein. This mutation might change the interaction between amino acids in stalk-head link region of HN protein and then induce the specific antibody to worse recognize the C22 strain, but it did not alter viral virulence and growth ability. Then, the C22 strain was attenuated via modification of the F protein cleavage site to generate a matched vaccine. Comparing to a mismatched vaccine (LaSota), this matched vaccine showed advantages in inhibiting viral shedding and tissue damage. However, both vaccines induced chicken to generate similar level of neutralizing antibodies against C22, C22mut (R138K) and LaSota. These results suggest that the epitope mutation is insufficient to help NDV escaping neutralizing antibodies of vaccinated chicken, supporting that the merits of NDV matched vaccine are not totally related to humoral immunity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Due to the particularity of origin area, the yield and price of Tibetan chicken are different from those in the plain areas, which leads to chickens from the plains being disguised as Tibetan chickens. In present study, Tibetan chicken and chicken from other four provinces in plain areas were distinguished by stable isotopes and chemometric methods. The cross-validation rate was 97.6%. Secondly, correlation between mean δ 13 C, δ 15 N, δ 2 H and δ 18 O values in chicken samples and environmentalparameters was investigated. These indicators are closely related to geographical environment. δ 13 C and δ 15 N values were positively correlated with longitude (R = 0.955) and altitude (R = 0.796), respectively. δ 18 O and δ 2 H values were negatively correlated with latitude (R = 0.903) and altitude (R = 0.938), respectively. At last, we used stable isotopes to trace Tibetan chicken from the different area of Tibet. When four stable isotope ratios were combined, we can distinguish them., (Copyright © 2021 Elsevier Ltd. All rights reserved.)