Daily Bulletin


The Conversation

  • Written by The Conversation
imageA fish out of time is as bad as a fish out of waterShutterstock/The Conversation

Over the course of evolution, humans and other animals have developed biological clocks. These act as internal timekeepers and are synchronised by environmental cues, mainly the daily alternation between day and night. These internal clocks control biological rhythms for things like temperature, alertness and tiredness, helping animals to adapt their daily and seasonal activities to the environmental changes.

In recent years, these insights have become increasingly interesting to the world of medicine. Reseachers have been looking into the extent to which drugs have different effects on people at different times of the day as a means of optimising treatment – a field known as chronotherapy. In particular, Professor Francis Levi of Warwick Medical School has pioneered applying these principles to optimise chemotherapy treatments for cancer patients. His work revolves around improving patients' quality of life by administering drugs at times when they can be best metabolised and are therefore least toxic.

One hour past the fish

While such work is still in its early stages in humans, the potential benefits have scarcely been considered in veterinary medicine at all. In my specialist area of aquaculture, otherwise known as fish farming, myself and some colleagues have been looking at some of the possibilities.

One of the major challenges in the field is disease outbreaks. At present, fish farms aim to keep their fish healthy by administering a variety of licensed drugs into the enclosures when there are outbreaks of disease. This happens more or less at random, depending on the operational constraints of the farm in question. Yet our recent research has found that the levels of both the toxicity and effectiveness of these drugs towards the fish varies at different times of day.

My colleagues and I have studied how the effects of several compounds on the physiology of fish change during the day. For example we looked at the effects of the anaesthetics which are used to minimise the stress responses of the fish. We found that if the fish were given the anaesthetics during the day, the drugs took effect much more quickly than at night, when the recovery period also took longer.

More recently our studies have looked at Atlantic salmon, the main aquaculture species in the UK. The focus has been the effects of chemicals used to control sea lice, the most significant parasite in salmon farming in Europe, estimated a few years ago to cost the world industry around €300m (£215m) a year.

imageSea lice: number one parasite in salmon farmsNorsk Havbrukssenter, CC BY-SA

Farms treat infected salmon in several ways, either in chemical baths or by adding drugs to the fishes' food. This has led to a surge in parasite resistance and can cause stress in the fish, which can reduce feeding. This in turn affects growth rates, as well as raising concerns about the fishes' welfare.

We have recently looked at the effects of hydrogen peroxide, one of the chemicals used to control sea lice, on the stress and toxicological responses of the salmon at different times of the day. Our initial results have found substantial time-dependent differences in the drug’s effects on the physiology of the fish. This is another sign that you can minimise negative effects by considering the timing of the treatment. Not only could it directly benefit the aquaculture industry by improving fish growth, it could improve its image as consumers increasingly demand higher standards of animal welfare.

When it comes to controlling sea lice there is much optimism in aquaculture around using “cleaner” fish called wrasse that feed on fish parasites. But their use in salmon aquaculture is still in its infancy – and further research is being conducted to optimise how they are produced and managed. While that takes place, the industry is still relying on chemicals, so there appears much scope for new strategies that could improve their effects.

Where we next cast our nets

imageAll a matter of timescale?Leo U, CC BY-SA

In future we are going to look at the effectiveness of drugs at controlling parasites when they are administered at different times, taking into account the effects on both the pathogens and the fish. Another area of enquiry that potentially looks interesting concerns using vaccines or immunostimulants to prevent diseases and reduce stress in farmed fish. Since fishes' immune systems also seem to rely on daily rhythms, it would not be surprising if the effects of such treatments varied throughout the day too.

Professor Giuseppe Piccione and his collaborators at the University of Messina in Italy pointed out as long ago as 2002 that chronotherapy should lead to a better use of medicines on farm animals. Our progress with fish certainly supports this. If medics in other fields both in human and animal medicine can learn to fine-tune treatments by adjusting administration times and doses accordingly, we could be looking at a great leap forward in the decades to come.

Luisa M. Vera Andujar does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

Authors: The Conversation

Read more http://theconversation.com/giving-fish-their-medicine-at-the-right-time-can-make-all-the-difference-44490

Writers Wanted

Heading back to the playground? 10 tips to keep your family and others COVID-safe

arrow_forward

Qatar expresses 'regrets' for 'any distress' to women invasively searched in baby incident

arrow_forward

Education & More – Family Tips on How to Settle in Bangkok

arrow_forward

The Conversation
INTERWEBS DIGITAL AGENCY

Politics

Prime Minister Interview with Kieran Gilbert, Sky News

KIERAN GILBERT: Kieran Gilbert here with you and the Prime Minister joins me. Prime Minister, thanks so much for your time.  PRIME MINISTER: G'day Kieran.  GILBERT: An assumption a vaccine is ...

Daily Bulletin - avatar Daily Bulletin

Did BLM Really Change the US Police Work?

The Black Lives Matter (BLM) movement has proven that the power of the state rests in the hands of the people it governs. Following the death of 46-year-old black American George Floyd in a case of ...

a Guest Writer - avatar a Guest Writer

Scott Morrison: the right man at the right time

Australia is not at war with another nation or ideology in August 2020 but the nation is in conflict. There are serious threats from China and there are many challenges flowing from the pandemic tha...

Greg Rogers - avatar Greg Rogers

Business News

AppDynamics Solves Visibility Gap Between Traditional Infrastructure and Cloud Environments

New Full Stack Observability Platform, Integration With Cisco Intersight Workload Optimizer and Cloud Native Visualisation Features Provide Cross Domain Insights and Analytics of Business Perfor...

Hotwire Global - avatar Hotwire Global

Why Your Small Business Should Bulk Buy Hand Sanitiser

As a small business owner, employee and customer safety is at the very top of your priority list. From risk assessments to health and safety officers, appropriate signage and proper briefing...

News Co - avatar News Co

How Phone Number Search In Sydney Can Help Your Business

To run a successful business, keeping track of your company and competitors are the major factors. With a lot of tools, available businesses have options to stay current. One way in which busine...

News Co - avatar News Co



News Co Media Group

Content & Technology Connecting Global Audiences

More Information - Less Opinion