The stimulation and inhibition of beta-2 adrenergic receptor on the inflammatory responses of ovary and immune system in the aged laying hens

BACKGROUND: Ovarian chronic inflammation has been known to incidence in the laying hen mainly via increasing laying frequency and microbial infection, especially during late stage of production period. This study was aimed to evaluate beta-2 adrenergic agonist (Beta-2 Adrenergic Agonist, BAA) Salmeterol and beta blocker (Beta Blocker, BB) Propranolol on the gene expression of the ovarian pro- and anti-inflammatory mediators, inflammatory responses of immune system, ovarian functions and, hormones in the laying hens on the late stage of production period. Forty-eight White Leghorn hens aged 92 weeks were used for 4 weeks to be supplemented by Salmeterol and Propranolol. Ovulation rate and follicular growth were determined based on laying frequency and ovarian visual evaluation, respectively; the mRNA expressions of follicular beta-2 adrenergic receptor (Beta-2 Adrenergic Receptor, β2ADR), cyclooxygenases (Cyclooxygenases, COX) 1 and 2, and cytokines were measured by real-time PCR. The plasma concentration of ovarian hormones, cellular, and humoral immune responses were measured via ELISA, heterophil to lymphocyte ratio (Heterophil to Lymphocyte ratio, H:L), and sheep red blood cell (Sheep Red Blood Cell, SRBC) test, respectively. RESULTS: As compared to control, both of BAA Salmeterol and BB Propranolol resulted in a significant decrease in the mRNA expression of β2ADR, cyclooxygenases, and pro- and anti-inflammatory cytokines (P < 0.01). A significant elevation was observed in the ovulation rate (P < 0.05), plasma estradiol content on both treated groups (P < 0.05), and the content of progesterone and was just significantly (P < 0.05) increased in Salmeterol group. H:L was reduced in BAA group (P < 0.05), and immunoglobulin (Ig) M was elevated in both treated hens, when compared to control. The results indicated that Salmeterol significantly increases body weight (P < 0.05). CONCLUSION: The stimulation and inhibition of beta-2 adrenergic signaling could reduce ovarian inflammatory condition in addition to enhancing laying efficiency in the aged laying hens.