Over 50 million salmon in Chile have now been treated with Elanco’s Lufenuron-based treatment Imvixa. Of these around 18.5 million had completed their efficacy period by May 1st and analysis shows that the average protection against Caligus rogercresseyi achieved has been 35.8 weeks, with results ranging from 24-55 weeks.
Imvixa – which is incorporated into smolt diets prior to their transfer to sea sites – has been approved for use against Caligus in salmonids in Chile since June of last year. According to Elanco, the results show that it is currently the most effective medicinal product against Caligus available in the country.
About 90% of the fish involved in the treatments so far have been produced in sites in Chile’s Region XI and the results suggest that several factors influence its efficacy.
"In addition to good smolt quality, a suitable level of incorporation of the product into the diet is essential, as well as establishing an optimal feeding regime. We recommend carefully monitoring this last process, so that the fish consume the indicated dose before being transferred to the sea,” advises Juan Pablo López, Technical Assistance Manager of Elanco Aqua.
In relation to the range of efficacy periods demonstrated in the results, López added that “each site is affected by multiple variables such as temperature, season, geographic infestation pressure, oceanography, genetics and smolt quality, among others. The challenge now is to analyse the data with our clients to establish the best treatment strategy."
Imvixa is an oral treatment, whose active principle is Lufenuron, which inhibits the formation of chitin in sea lice, preventing the parasite from developing and transforming into an adult.