Feed for better barrier functions and health in salmon under Arctic conditions

Offentlig prosjektsammendrag

Wound problems in salmon are a bigger problem in Finnmark than further south in Norway. At Cermaq, there is a 10-15% downgrading of salmon in Finnmark and typically 3-6% of salmon in Nordland. This difference is mainly due to wound problems. The wounds often develop during the long winter in Finnmark, as fish at low temperatures have less ability to wound healing. Some of the wound problems can be due to handling (sorting, transport, lice treatment), but also unfavorable environmental conditions. In addition, there are the bacteria that cause winter sores and tenacibaculosis. Although these bacteria occur in salmon production along the entire Norwegian coast, they are a particular problem in Finnmark. The low seawater temperature in addition to nutritional conditions are probably important factors for increased susceptibility to these diseases. In recent years, mechanical treatment of salmon lice has also contributed to increasing challenges for the skin health of salmon in Finnmark. Experiments on a smaller scale, and under other environmental conditions, show that an increased amount of EPA+DHA and zinc (Zn) is important for skin health and the ability to heal wounds in salmon. It is also well known that Zn is an important factor for good intestinal health in other animals, but no such documentation exists for fish. The aim of the project is to document the effect of increased levels of EPA+DHA combined with a more bioavailable Zn source in the feed on general fish health, as well as the ability to prevent wounds, strength in wound healing and increase fillet quality (less melanin and better pigmentation). The project is an activity under the Arctic Salmon Research Center, which aims to increase the general knowledge about nutrition and feed composition in salmon under Arctic environmental conditions in Finnmark (with varying day length and low sea temperatures) to optimize growth, feed utilization, fish health and product quality.