Salmon4Sustain

Offentlig prosjektsammendrag

Over the years there has been a clear trend to produce Atlantic salmon feed with higher energy levels. Such energy dense diets have generally been shown to improve feed utilization and growth. However, reducing the dietary protein to-lipid ratio may lead to increased deposition of fat in the muscle and visceral cavity. There is evidence that high levels of body lipids may reduce feed intake and growth in salmonids and is often referred to as lipostatic regulation. Thus, there is a risk of lowered growth prior to and during periods with increased feed intake and high fat accumulation when feeding high-fat diets. Increasing the nutrient density further may be a challenge, and the utilization of the nutrients should be looked into to see if there is a potential for an increased utilization/retention efficiency, especially of protein (amino acids). The majority of farmed Atlantic salmon is reared in sea cages that are exposed to seasonal environmental changes. Several studies report seasonal variation in growth and lipid deposition of Atlantic salmon, mainly due to changes in seawater temperature and photoperiod. In relation to season, farmed salmon show high fat deposition and increased condition factor, with a concomitant increase in feed intake and weight gain during the Summer and Autumn period. Prolonged high seawater temperatures and declining day length characterizes the Autumn period. During the late Autumn and Winter, a decline or stagnation in the level of muscle fat in salmon is often observed, which relates to reduced feed intake and increased FCR during low sea temperatures and short-day length. The aim of the project should be to develop a new high performance feeding concept for Atlantic salmon between (1 to 4.5 kg) through size but also seasonal optimization of the DP/DE ratio. This concept will improve protein retention efficiency, FCR, fillet yield and minimize nitrogen/ammonia excretion contributing to a more efficient and profitable production.