Abstract
Post-smolt Atlantic salmon were fed control (C), plant protein- (PP), and animal protein (AP)-based diets over a 90-day period. At trial start, the outline shape variation in the salmon body was recorded using two-dimensional Cartesian coordinates of a combination of 12 landmarks (LM) and three semi-landmarks from each of the 48 fish. The identical landmarks were then assessed at trial end for the differing dietary treatments. These datasets were used to determine whether diet exerted a measurable effect on body shape to enable authentication of fishmeal/fish oil-free status. Most differences in shape at trial end were visualized at the base of the dorsal and pelvic fins and caudal peduncle. The greatest shape variation between PP and AP groups was found at the base of the pectoral and pelvic fins. While PP and AP groups were more similar in shape than control fish, the recorded differences were not significant enough to verify dietary origins. The number of animals employed and the length of the trial period were likely insufficient to distinguish alterations in body shape with any certainty. Future trials should employ larger numbers of animals and be of longer length to verify whether PP-based feeds cause changes in body shape.