Feeds support sea bream through cold winter conditions
Low Mediterranean sea temperatures from November to May can stress sea bream and cause problems known as winter syndrome and petechial rash skin syndrome, reports www.megafishnet.com with reference to Skretting.
These conditions impact profitability through reduced production and sales. According to Carlos Zarza, Fish Health Coordinator for Skretting Southern Europe, they can be minimised with the right feeds and feeding regimes.
"As water temperatures go below 16 ºC the sea bream lose their appetite. Reduced nutrition exacerbates other physiological effects such as slower metabolism and a depressed immune system. That leads to lower or negative growth, larger fish can lose 25-50g over the winter, and fish become vulnerable to infections that may lead to mortalities." Winter syndrome is a greater problem in the first winter, with fish below 200g. In north Mediterranean locations it can cause problems again the next year. However, in many locations, especially in the south, petechial rash skin syndrome has become the main problem in the second winter. The impact is largely cosmetic as affected fish look unattractive and the farmers cannot sell them. The rash responds to antibiotics but then fish cannot be sold until after the withdrawal period. Either way, farmers lose income.
Skretting recommends a combination of two Active Nutrition diets and carefully managed feeding as a strategy for winter. "Where winter syndrome is the major problem, we suggest introducing Protec Winter early in November to prepare the fish for winter," says Zarza. "Its combination of immunostimulants, selected vitamins, minerals and natural ingredients stimulates the immune system, boosts feed intake and discourages pathogenic bacteria in the gut. From January to March React Winter is recommended, with ingredients specifically targeting effects of the lowest temperatures. Farmers should return to Protec Winter in April and May for the recovery phase. Where petechial rash skin syndrome is more important, Protec Skin is an alternative to Protec Winter. The unique combination of vitamins and natural ingredients supports skin structure and function and helps wound healing. Information from customers indicates significantly fewer problems with these regimes, for example petechial rash skin lesions held at around 1-2%, and better maintenance of weight, even growth in some instances."