Acta Veterinaria et Zootechnica Sinica ›› 2020, Vol. 51 ›› Issue (4): 772-782.doi: 10.11843/j.issn.0366-6964.2020.04.013

• ANIMAL NUTRITION AND FEEDS • Previous Articles     Next Articles

Effects of Dietary Arginine Levels on Immune Function and Anti-FAdV-4 Capacity of Broilers

LIN Zhixin1, ZHOU Jiaxin1, CHEN Lizhen1, GAO Yuyun1, WANG Quanxi1,2, WANG Changkang1*   

  1. 1. College of Animal Science(College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou 350002, China;
    2. Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health, Fujian Agriculture and Forestry University, Fuzhou 350002, China
  • Received:2019-11-13 Online:2020-04-25 Published:2020-04-21

Abstract: The aim of this study was to investigate the effects of dietary arginine levels on immune function in broilers and explore the mechanism of arginine anti-fowl adenovirus serotype 4 (FAdV-4). Three hundred one-day-old broilers(Ross 308) were randomly allocated to 5 groups with 5 replicates per group and 12 chickens per replicate. The experimental diets were set to 5 arginine levels of 0.96%, 1.20%, 1.44%, 1.68%, and 1.92%, respectively. The feeding trial lasted for 21 days. Four broilers were randomly selected from each replicate to determine serum immune index and immune relative organ index. Then, six broilers were randomly selected from each replicate and randomly divided into infected group and control group. The chickens in the infected group were individually infected with 0.2 mL of FAdV-4 NP strain (TCID50=10-6.23/0.01 mL) by intramuscular injection; the chickens of control group were individually injected with the same volume of sterile saline. Two days after infection, mortality rate and disease incidence were calculated. iNOS levels in livers were determined by ELISA. iNOS mRNA expression and viral load in livers were detected by qPCR. The results showed that:1) Three arginine levels of 1.44%, 1.68%, and 1.92% significantly increased spleen index (P<0.05) and arginine level of 1.68% significantly increased thymus index (P<0.05), while arginine level of 0.96% significantly reduced spleen index, thymus index and bursal index (P<0.05). 2) The arginine level of 1.68% significantly increased serum GLO, IgG levels and G/A value (P<0.05). Arginine level of 0.96% significantly decreased serum GLO and IgG levels (P<0.05). 3) The arginine level of 0.96% significantly decreased serum IL-1β, TNF-α, iNOS and NO levels (P<0.05), while the arginine levels of 1.68% and 1.92% significantly increased IL-1β, TNF-α, IFN-γ and iNOS (P<0.05). 4) After broilers infected with FAdV-4, the mortality rate in the 0.96% group was significantly higher than those of 1.20%, 1.44%, 1.68%, and 1.92% groups (P<0.05). 5) ELISA results showed that 1.44%, 1.68%, and 1.92% arginine levels could significantly increase iNOS levels in liver after infection. 6) The arginine levels of 1.44%, 1.68%, and 1.92% significantly increased the expression of iNOS mRNA in livers (P<0.05). After broiler were infected with FAdV-4, the level of iNOS mRNA in the livers were significantly decreased (P<0.05). High levels of arginine (1.44%, 1.68%, and 1.92%) increased the level of iNOS mRNA expression in the livers after broilers infected with FAdV-4 (P<0.05) and significantly reduced the viral load of the livers (P<0.05). It could be seen that deficiency of arginine in the diet could reduce the immune function and anti-FAdV-4 virus ability of the chicken. Increasing arginine levels in broiler diets not only improved immune organ index, serum immune factor levels, and iNOS mRNA expression levels in the livers, but also reduced viral load of livers, thereby improving immune function and antiviral capacity.

Key words: arginine, immune function, iNOS, FAdV-4

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