Effects of antibacterial peptide on cellular immunity in weaned piglets1,2

Abstract

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.

Use of antimicrobial peptides as a feed additive for juvenile goats

“…However, there is insufficient information on the effects of AMPs on rumen digestion, as only a limited number of inconclusive studies have examined the use of AMPs as alternatives to feed antibiotics and growth promoters in ruminant nutrition. Previous studies in our laboratory have shown that adding AMPs (composed of recombinant swine defensin and a fly antibacterial peptide at a blending ratio of 50:50) in feed can improve growth and immunity of weaned piglets 15 . Based on our previous findings and the reported bactericidal effects of AMPs, we hypothesized that dietary AMP supplementation could affect rumen microbiology, and therefore ruminal fermentation.…”

“…In addition to antimicrobial properties 10 , previous studies have demonstrated antifungal 11 , antiviral 12 , anti-parasitic 13 , and antitumor activities 14 . AMP-induced immunoregulatory and antioxidant activities have been shown to be mediated by cationic charge, amphipathicity, amino acid composition, and structure 15 . AMPs have also been demonstrated to improve performance, nutrient retention, and intestinal morphology, and to reduce the incidence of diarrhoea in livestock animals 16 – 19 .…”

Effects of composite antimicrobial peptide on growth performance and health in weaned piglets

“…The levels of CAP that were used in the study were based on the recommendations of the company and reports by Ren et al . (). The basal diet containing no antibiotics which is presented in Table was formulated according to the nutrient requirements suggested by the National Research Council (NRC ).…”

Dietary Intervention to Reduce E. coli Infectious Diarrhea in Young Pigs

“…Many research findings have demonstrated that antimicrobial peptide treatment could inhibit protein and nucleic acid synthesis, suppress bacterial cell wall synthesis, as well as inhibit enzyme activities in bacteria [174]. In addition to their antibacterial properties, antimicrobial peptides may also act as epithelial "preservatives" or immunomodulators to protect host against enteric infectious agents [166,175,176].…”