Assessment of antibacterial properties and the active ingredient of plant extracts and its effect on the performance of crucian carp (Carassius auratus gibelio var. E'erqisi, Bloch).
BACKGROUND
In this study, the antibacterial properties and active ingredient of plant extracts and its effect on the performance of crucian carp (Carassius auratus gibelio var. E'erqisi, Bloch) were assessed.


RESULTS
The transmission electron microscopy and flow cytometric analysis showed that the antibacterial activity of plant extracts is due to the disruption of the cell membrane and the leakage of cytoplasmic contents. The UPLC-MS/MS analysis showed that the contents of gallic acid, (-)-epigallocatechin, (+)-catechin, (-)-epigallocatechin gallate, (-)-epicatechin gallate, aloe-emodin, rhein, emodin, chrysophanol, and physcion, were 5.27%, 3.30%, 1.08%, 19.32%, 5.46%, 0.23%, 0.56%, 1.28%, 0.75% and 0.39% in plant extracts, respectively. Results of feeding experiment showed that feeding crucian carp with 1.0% and 2.0% plant extracts significantly enhanced specific growth rate, serum total protein, lysozyme, catalase and superoxide dismutase activities, and decreased the feed conversion rate, malondialdehyde contents and the mortality rate (P < 0.05).


CONCLUSIONS
It can be concluded that plant extracts added to fish feed can act as natural antimicrobial and immunostimulants to prevent pathogenic infection, enhance immune response, and promote growth of the fish.
Supervision and Testing Center Food Quality, Ministry of Agriculture, Xinjiang Academy of Agriculture and Reclamation Science, Shihezi, PR China. shzlcx2002@163.com
Chunxia
C
Lu
Xiaoling
X
Luo
Ruifeng
R
Luo
Xia
X
Chen
Lijie
L
Xing
Zonggui
Z
Tang
Hongmin
H
Li
D000276:Adjuvants, Immunologic / Q000032:analysis / Q000494:pharmacology; D000333:Aeromonas / Q000187:drug effects; D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001798:Blood Proteins / Q000378:metabolism; D002347:Carps / Q000254:growth & development / Q000382:microbiology; D002374:Catalase / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D005393:Fish Diseases / Q000382:microbiology / Q000517:prevention & control*; D006128:Growth / Q000187:drug effects*; D007109:Immunity / Q000187:drug effects; D007239:Infections / Q000382:microbiology; D008315:Malondialdehyde / Q000378:metabolism; D009113:Muramidase / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D010941:Plant Tumors; D012250:Rheum / Q000737:chemistry*; D029045:Rhus / Q000737:chemistry*; D013482:Superoxide Dismutase / Q000378:metabolism
D000276:Adjuvants, Immunologic; D000900:Anti-Bacterial Agents; D001798:Blood Proteins; D010936:Plant Extracts; D008315:Malondialdehyde; D002374:Catalase; D013482:Superoxide Dismutase; D009113:Muramidase