Effects of antibacterial peptide on cellular immunity in weaned piglets

• Published in: Journal of animal science 2015-01, Vol.93 (1), p.127-134
• Main Authors: Ren, Z H, Yuan, W, Deng, H D, Deng, J L, Dan, Q X, Jin, H T, Tian, C L, Peng, X, Liang, Z, Gao, S, Xu, S H, Li, G, Hu, Y
• Format: Article
• Language: English
• Subjects: Animals; Antimicrobial Cationic Peptides - pharmacology; Cell Cycle - drug effects; Diet - veterinary; Female; Immunity, Cellular - drug effects; Immunity, Cellular - immunology; Lymphocyte Activation - drug effects; Male; Polysaccharides; Spleen - drug effects; Sus scrofa - immunology; Sus scrofa - metabolism; T-Lymphocyte Subsets - immunology
• ISSN: 1525-3163
• DOI: 10.2527/jas.2014-7933

The aim of this study was to evaluate the effects of antibacterial peptide (ABP) sufficiency on cellular immune functions by determining the spleen cell cycle and apoptosis, peripheral blood T cell subsets, and T cell proliferation function in weaned piglets. A total of 90 piglets (Duroc × Landrace × Yorkshire) of both sexes were randomly allotted to 5 dietary treatments. Each treatment consisted of 3 replicates with 6 piglets per replicate. The dietary treatments consisted of the negative control (NC; basal diet), positive control (PC; basal diet supplemented with 400 mg/kg Astragalus polysaccharide), and ABP (basal diet mixed with 250, 500, and 1,000 mg/kg ABP). The experimental lasted for 28 d. Two piglets from each replicate were selected randomly for blood samples extraction from the jugular vein to obtain peripheral blood T cell subsets, and T cell proliferation function analysis was performed on d 32, 39, 46, and 53. Two piglets from each replicate were selected and euthanized to observe the spleen cell cycle and apoptosis on d 39 and 53. In ABP-sufficient piglets, the G0/G1 phase of the spleen cell cycle was much lower (P < 0.05) and the S and G2 + M phases and proliferation index (PI) were greater (P < 0.05) than in NC piglets. The percentage of apoptotic cells in the spleen significantly decreased under ABP sufficiency (P < 0.05). The proliferation function of peripheral blood T cells increased (P < 0.05) in ABP-sufficient piglets. Percentages of CD3 (+) and CD3 (+)CD4 (+) ratios (d 39, 46, and 53) and CD4 (+)CD8 (+) ratios (d 32, 39, 46, and 53) increased remarkably (P < 0.05) under ABP sufficiency compared with NC. These results suggest that ABP sufficiency could increase the T cell population and proliferation function of T cells and could induce decreased percentages of apoptotic cells. Overall, the cellular immune function was evidently improved in weaned piglets. We suggest optimal dosages of 500 mg/kg ABP for 4-wk addition and 1,000 mg/kg ABP for 2-wk addition.