Acta Veterinaria et Zootechnica Sinica ›› 2023, Vol. 54 ›› Issue (3): 1281-1299.doi: 10.11843/j.issn.0366-6964.2023.03.039

• CLINICAL VETERINARY MEDICINE • Previous Articles     Next Articles

Study on Biological Activity of the Residue and Fermentation Products of Lianhua Qingwen

LIU Guang1,2, GONG Chengyan1, NIU Kaimin1, ZHANG Shuo3, TAO Deng3, MA Jun4, WU Xin1, YIN Yulong1, TANG Yulong1*   

  1. 1. Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central of Ministry of Agriculture, Hunan Provincial Engineering and Technology Center for Healthy Livestock and Poultry Production, Key Laboratory of Agro-Ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China;
    2. College of Animal Science and Technology, Hunan Agricultural University, Changsha 410125, China;
    3. Yunnan Southwest Agriculture and Animal Husbandry Group Co. LTD., Kunming 650217, China;
    4. Shijiazhuang Yiling Pharmaceutical Co. Ltd., Shijiazhuang 050035, China
  • Received:2022-03-02 Online:2023-03-23 Published:2023-03-21

Abstract: The purpose of this experiment was to study the biological activities of Lianhua Qingwen residue and its fermentation products, and to investigate the differences among the methods of fermentation including natural, optimised fermentation 1 (4MYL) and optimised fermentation 2 (Y4ML) in terms of the alteration of the nutrient content of the residue and the antibacterial and antiviral effects of the ethanolic and aqueous extracts. Broth dilution method was used to determine the minimum inhibitory concentration (MIC) of different extracts of drug residue before and after fermentation against three pathogenic strains of Haemophilus parasuis (HPS), Streptococcus suis type 2 (SS2) and Enterotoxic Escherichia coli (ETEC); African green monkey kidney cells (Vero), African green monkey embryonic kidney cells (MARC-145) and porcine kidney cells (PK-15) were infected with pseudorabies virus (PRV), porcine circovirus type 2 infection (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV), respectively. The morphological changes of cells were observed by fluorescence microscope, and the virus nucleic acid was detected and quantified by real-time fluorescence quantitative PCR as an evaluation index of the antiviral effect of drugs in vitro. The results showed that the ethanolic and aqueous extracts of Lianhua Qingwen medicinal dregs showed inhibitory effects on HPS and SS2 strains, but had no inhibitory effect on ETEC; They all showed antiviral activity against the three test viruses, but there existed certain differences in antiviral activity. After fermentation, the ethanolic and aqueous extracts enhanced their antibacterial and antiviral activities and inhibited ETEC. It can be concluded that the extract of Lianhua Qingwen residue has different degrees of antibacterial and antiviral effects, can effectively inhibit HPS, SS2 and other common pathogenic bacteria and viruses in the process of pig breeding, and antibacterial and antiviral effect are enhanced after fermentation. The above results supported that Lianhua Qingwen residue extract has the potential to be developed into animal feed or feed additive.

Key words: Lianhua Qingwen residue, fermentation, antibacterial, antiviral

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