China Animal Husbandry and Veterinary Medicine ›› 2024, Vol. 51 ›› Issue (9): 4174-4181.doi: 10.16431/j.cnki.1671-7236.2024.09.044

• Basic Veterinary Medicine • Previous Articles    

Effect of Bamboo Leaf Flavonoid on Immune Efficacy of Chick Embryo Inoculation with Newcastle Disease Vaccine

JIANG Xinrui1, FENG Helong2, YANG Hongchun3, JIANG Liren2, WANG Hongcai2, ZENG Zhe2, ZUO Bo2, ZHANG Tengfei2, LUO Qingping2,4, SHANG Yu2, WEN Guoyuan2   

  1. 1. College of Animal Science and Technology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China;
    2. Hubei Provincial Key Laboratory of Livestock and Poultry Pathogen Microbiology, Key Laboratory of Prevention and Control Agents for Animal Bacteriosis Ministry of Agriculture and Rural Affairs, Institute of Animal Husbandry and Veterinary, Hubei Academy of Agricultural Sciences, Wuhan 430064, China;
    3. College of Animal Science and Technology, Guangxi University, Nanning 530004, China;
    4. Hubei Hongshan Laboratory, Wuhan 430070, China
  • Received:2024-01-30 Published:2024-08-27

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Abstract: 【Objective】 The aim of this experiment was to explore the effect of bamboo leaf flavonoid (BLF) as a vaccine adjuvant on the immune effect of Newcastle disease (ND) vaccine in chicken embryos. 【Method】 The experiment selected 108 18-day embryonic SPF hatching eggs and randomly divided into 3 groups:Control group (no injection of any substance), TS group (injection of 0.1 mL 103.0 EID50/0.1 mL of Newcastle disease virus (NDV) TS09-C vaccine strain) and BLF＋TS group (injection of 0.1 mL of a mixture of 2% BLF and 103.0 EID50/0.1 mL NDV TS09-C vaccine strain), with 36 eggs in each group.During the experiment, the hatching rate of eggs and the survival rate of chicks were calculated.When the chicks were 7，14，21 and 28 days old, 3 chicks from each group were randomly selected for slaughter, then spleen, bursa of Fabricius, and thymus tissue were collected, and immune organ indexes were counted.The subwing vein blood of chicks was collected and serum antibody and cytokine levels were measured.The challenge protection test was carried out with NDV strain F48E9 at 28 days of age.After challenge, the status of the chicks was observed every day, and the weight change was recorded.On the 3rd day after the challenge, 3 chicks in each group were randomly selected for slaughter.Duodenum, lung and trachea tissues were collected and viral load in different tissues of chicks were detected. 【Result】 After chicken embryo inoculation, the hatchability rate of chicks in BLF＋TS group was 100%, and the survival rate was 97.22%.Compared with TS group, the spleen, bursa of Fabricius and thymus indices as well as the serum levels of interleukin 6 (IL-6) and interferon-γ (IFN-γ) contents in BLF＋TS group were significantly increased (P＜0.05).The results of the challenge test showed that the survival rate of chicks in BLF＋TS group after challenge was 100%.The body weight increase rate of BLF+TS group was significantly lower than that of healthy control group at 2-4 days after challenge (P＜0.05).The body weight growth rate of chicks in BLF＋TS group was significantly higher than that of TS group at 3-7 days after challenge (P＜ 0.05).The viral load in the respiratory tract and digestive tract tissues of chicks in BLF＋TS group after challenge was significantly lower than that in TS group (P＜0.05). 【Conclusion】 BLF could be safely used as an immune adjuvant for chicken embryo vaccination, and could help chicks establish early immune protection and further improve the immune effect of ND vaccine.The results provided reference for the development of efficient chicken embryo immune vaccine adjuvants.

Key words: chick embryo inoculation; bamboo leaf flavonoids; Newcastle disease vaccine; vaccine adjuvant

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