Distinct immune tones are established by Lactococcus lactis BFE920 and Lactobacillus plantarum FGL0001 in the gut of olive flounder (Paralichthys olivaceus).
The immune tone is defined as an immunological state during which the readiness for immune response is potentiated. The establishment of immune tone in the gut of olive flounder (Paralichthys olivaceus) was investigated by feeding Lactococcus lactis BFE920 (LL) or Lactobacillus plantarum FGL0001 (LP). LL-fed flounder showed significantly increased levels of regulatory genes (FOXP3, IL-10, and TGF-β1), CD18, and CD83 in the gut. In contrast, LP feeding drastically increased proinflammatory genes (T-bet, IL-1β, and IFN-γ) and CD18. This indicates that LL and LP establish different types of local immune tones in the gut through differential activation of innate immune cells: LL activates both macrophages and dendritic cells while LP activates macrophages only. Both of the immune tones required at least a total of 6 probiotic feeds during 72 h for a stable establishment. Once established, the type of immune tone remained steady even up to 30 days (a total of 60 feeds) probiotics feeding. The LL-induced regulatory immune tone enhanced the level of occludin, a tight junction molecule, significantly more than that observed with the proinflammatory immune tone established by LP feeding. Consequently, LL-fed fish showed considerably lower gut permeability than that of the LP-fed group. Furthermore, when orally challenged by Edwardsiella tarda, LL-fed flounder survived at a significantly higher rate than LP-fed fish. The data clearly demonstrate that individual probiotics establish distinct types of immune tone in the fish gut, which in turn influences the immunological status as well as the physiology of the gut. Selection of proper probiotics may be essential for optimal effects in aquaculture farming.
School of Life Science, Handong University, Pohang 791-708, Republic of Korea.
Bo Ram
BR
Beck
School of Life Science, Handong University, Pohang 791-708, Republic of Korea.
Joon Hyun
JH
Song
School of Life Science, Handong University, Pohang 791-708, Republic of Korea.
Byung Sun
BS
Park
School of Life Science, Handong University, Pohang 791-708, Republic of Korea.
Daniel
D
Kim
School of Life Science, Handong University, Pohang 791-708, Republic of Korea.
Jin-Hwan
JH
Kwak
School of Life Science, Handong University, Pohang 791-708, Republic of Korea.
Hyung Ki
HK
Do
School of Life Science, Handong University, Pohang 791-708, Republic of Korea.
Ah-Ram
AR
Kim
Biotechnology Research Division, National Institute of Fisheries Science, Busan 46083, Republic of Korea.
Woo-Jin
WJ
Kim
School of Life Science, Handong University, Pohang 791-708, Republic of Korea. Electronic address: sksong@handong.edu.
Seong Kyu
SK
Song
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D004032:Diet / Q000662:veterinary; D005412:Flatfishes / Q000276:immunology*; D041981:Gastrointestinal Tract / Q000276:immunology; D056747:Immunomodulation; D048191:Lactiplantibacillus plantarum / Q000737:chemistry*; D013294:Lactococcus lactis / Q000737:chemistry*; D019936:Probiotics / Q000008:administration & dosage*
Immune tone; Lactobacillus plantarum FGL0001; Lactococcus lactis BFE920; Olive flounder; Probiotics