Recording feed intake of postsmolt salmon using Xrays
The purpose of this research is to repeatedly record how much feed individual Atlantic salmon eat and match this with growth, in order to determine how to breed for more feed efficient salmon. Feed comprises around half of the production cost and 70-80 % of the climate gas emission from salmon production. Thus, breeding for more feed efficient salmon would benefit the environmental footprint of Atlantic salmon farming and improve the profitability. The largest difficulty is measuring how much feed individual Atlantic salmon eat. The X-ray method for measuring individual feed intake developed in the 1980s were used with success in full-sib groups of small salmon in freshwater in a previous experiment (FOTS ID 23714) and the results are promising for the use of the method to select fish with different feed efficiency.
Measuring feed intake in small fish in freshwater (FW) is less work-intensive, cheaper and less stressful for the fish than using larger fish in seawater (SW). On the other hand, in practical farming it is the feed efficiency in large fish in SW that counts, economically and environmentally. Therefore, it is important to investigate whether the genetic differences in feed efficiency obtained in FW is representative for the SW stage. For this we have 365 salmon which are full-sibs to those used in FW (FOTS ID 23714) which has already been PIT-tagged (standard 12 mm PIT tags).
The salmon (average weight ca 0.24 kg) will be recorded for feed intake (using Xrays) on three occasions over the entire growth period 120 days. The salmon will be fed standard feed which meets all nutritional requirements with the addition of 1-2 % small glass beads.
The methods and X-ray equipment have been improved over the last 40 years to the point where fish can be recorded over very short periods of time out of water. Although the time out of water is greatly reduced to seconds, it still causes the fish some distress to be out of the water.
Measuring feed intake in small fish in freshwater (FW) is less work-intensive, cheaper and less stressful for the fish than using larger fish in seawater (SW). On the other hand, in practical farming it is the feed efficiency in large fish in SW that counts, economically and environmentally. Therefore, it is important to investigate whether the genetic differences in feed efficiency obtained in FW is representative for the SW stage. For this we have 365 salmon which are full-sibs to those used in FW (FOTS ID 23714) which has already been PIT-tagged (standard 12 mm PIT tags).
The salmon (average weight ca 0.24 kg) will be recorded for feed intake (using Xrays) on three occasions over the entire growth period 120 days. The salmon will be fed standard feed which meets all nutritional requirements with the addition of 1-2 % small glass beads.
The methods and X-ray equipment have been improved over the last 40 years to the point where fish can be recorded over very short periods of time out of water. Although the time out of water is greatly reduced to seconds, it still causes the fish some distress to be out of the water.