South American scientists search for ‘natural antibiotic’
Scientists in Chile and Peru are joining forces to investigate peptides that may combat bacterial problems in Peru’s trout farming industry.
The peptides – chains of amino acids that form part of a protein – will be tested against a bank of bacteria related to fish maintained by researchers in Peru, reports Fish Farming Expert’s Chilean sister site, Salmon Expert.
The work involves the inoculation of peptides found in the fish, with the aim of developing a natural antibiotic.
Cellular communicator
“Peptides are derived from a protein that is present in trout which is a cellular communicator (cytokine),” said Dr Paula Santana of the Institute of Applied Chemical Sciences at Chile’s Autonomous University (UA) and director of the collaborative project.
“The interesting thing about this is that we work with molecules that are synthesised and have no chemical modifications other than the native molecule that is present in the fish.”
Dr Nieves Sandoval, of the Faculty of Veterinary Medicine at the National University of San Marcos in Peru, explained that the same bacterial problems that have occurred in fish farming in Chile are being seen in Peru.
“We are a younger industry. However, due to the increase in production we already have health problems, morbidity and mortality, mainly caused by bacteria (Yersinia ruckeri, Aeromonas salmonicida, Aeromonas hydrophila and Flavobacterium psychrophilum). These are the same ones that have already generated difficulties in the Chilean fish industry,” said the scientist.
Pathogenicity
The peptides, characterised by Chilean specialists, will be tested against the bacteria bank that researchers maintain in Peru. The procedure involves reactivating the bacteria that come from disease outbreaks in fish farms.
“Here in Chile we have been testing the effect of peptides on bacteria that do not have the pathogenicity of the bank of Peru,” said Santana.
“We will test to see if the peptide is capable of having an action against these bacteria with different pathogenicity, outside the organism. If this works, the second part of our work will be to inoculate the sick fish with the peptide and see if it is able to protect it.”
Generalised infection
Scientists already know that the peptide can be effective in case of a generalised infection of the bacteria throughout the fish’s body (septicemia). If the peptide proves to be effective in fish in Peru, the necessary dosage that the animals will require will also be tested.
“Theoretically, we expect the peptide to show its antimicrobial activity, so fewer fish should die or they shouldn’t die (at all). The work will already be a success if mortality decreases,” said Sandoval.
