A scientist injecting silver nanoparticles intramuscularly in an abalone. (Photo: Conacyt)

Nanomedicines to treat marine animal disease investigated

MEXICO
Friday, December 15, 2017, 23:10 (GMT + 9)

Mexican scientists are analyzing the feasibility of using silver nanoparticles to treat diseases that affect commercially interesting marine animals and that are bred via aquaculture techniques, such as shrimp, abalone, oyster and different fish species.

In an interview with Conacyt Information Agency, Dr. María Cristina Chávez Sánchez, a specialist of the Centre for Research in Food and Development (CIAD), Mazatlán unit, and responsible for the project, said that diseases represent one of the factors with the greatest negative impact on aquaculture e development.

"There are no - against many viral, bacterial and parasitic diseases - really preventive or curative methods that are effective, and many of them are prohibited, there are few drugs accepted for their use," she said.

Given that there are no antecedents that indicate the effect that silver nanoparticles will have on marine organisms, in the first stage, the researchers focus on analyzing their repercussions on the safety of animals, mainly taking into account that they will become food for humans.

"Once we determine that the silver nanoparticles do not harm them or it is minimum because with any drug that is introduced to the body we are somehow introducing something that does not belong to it and there are always reactions that can be from light to deadly, then If the damage is zero or minimum, then we will begin to treat the different microorganisms that we want to counterattack," explained Dr. Chavez Sánchez.

The next step will be to investigate what happens with nanoparticles, that is, to determine whether or not they accumulate in the body of fish, molluscs or shrimp that humans are going to eat, and if there is an effect on safety.

Dr. Jorge Cáceres Martínez, a researcher at the Department of Aquaculture at CICESE, analyzes the effect of silver nanoparticles to combat the dehydration syndrome of abalone, a chronic disease that produces mortalities that have a significant effect on the fishery and the farmed product.

In the absence of effective alternative treatments, he performs experiments by injecting the silver nanoparticles intramuscularly into abalone, whose circulation system distributes them throughout the body, to see their effect on abalone tissues, the possible bioaccumulation of nanoparticles and their effect on the causal agent of the dehydration syndrome.

"The use of silver nanoparticles directly in seawater is limited since their stability is quickly lost and the possible use of baths of sick animals does not seem to be practical. In that sense, its use via injection could have a greater potential as long as it is demonstrated that there is no toxicity for the host or risks of bioaccumulation," explained the researcher.

He pointed out that the hypothesis on the toxicity of silver nanoparticles is being tested in two ways: first, the effects when using them directly on the pathogen, and second, when administered on the host with the pathogen - in this case the host is the abalone -.

"What we have found so far is that it is definitely not a treatment that goes to the target pathogen, but rather it is a kind of chemotherapy where, if the host cell resists, then the cell of the pathogen will be affected," Cáceres Martínez explained.

To verify that the abalone has the capacity to resist the treatment and that there is no risk of bioaccumulation, it will be considered as a control mechanism that can be used to broodstock or in land animal breeding lots, where a controlled environment can be maintained.

The scenario that researchers face with shrimp is not very different from that of abalone: ​​the first phase focuses on determining if the silver nanoparticles negatively affect the organism and in what dose they can be administered to treat the white spot syndrome, whose virus causes mortalities in shrimp production.

Dr. María Cristina Chávez Sánchez indicated that the work began with the detection of fatal doses, which were reduced until finding doses that could be therapeutic or preventive.

She highlighted that several bioassays have already been carried out, some of them with food, and now they are working on the histological analysis of shrimp to detect the effects of silver nanoparticles on their organs and tissues.

The project is financed with resources from the Sectoral Research Fund for Education SEP-CONACYT and collaborates with CIAD, specialists from the Centre for Scientific Research and Higher Education of Ensenada (CICESE), the Centre for Biological Research of the Northwest (CIBNOR) and Michoacan University of San Nicolás de Hidalgo (UMSNH).

editorial@seafood.media
www.seafood.media

Print