Significant differences in fat digestibility
between feed companies were, in fact, evident from the regression
models in the present study. In addition, fat digestibility increased
with ambient water temperature. Low temperature has been described
as a factor affecting fat digestion as reviewed by Turchini et al. (2009),
and inclusion of saturated fatty acids is regarded critical at low ambient
temperatures. The results of the present study suggest that the negative
influence of temperature on fat digestibility also can be seen in commercial
salmon production. The observed differences between feed companies
may be explained by different models for fat digestion efficiency at
low temperatures, and suggest that there is a potential for further improvement
of controlling fat digestion at low temperatures.