Maxi-Gen™ Plus: A nucleotide-containing product that reduces stress indicators and improves growth performance during smoltification in Atlantic salmon (Salmo salar)

Abstract

Three trials were conducted to determine the effects of dietary nucleotides fed as Maxi-Gen™ Plus on the stress level, growth performance and intestinal histology of in-season and off-season Atlantic salmon smolts. Twenty-four hour, 40ppt salinity tests determined the hypo-osmoregulatory ability of Atlantic salmon during smoltification gradually improved as the dietary inclusion rate of Maxi-Gen™ Plus increased from 0.05 to 0.60%, which indicates an extended period of time for effective transfer to seawater. Growth performance evaluated as weight gain, feed consumption and feed conversion ratio showed diets containing 0.40 to 0.60% Maxi-Gen™ Plus enhanced the growth performance of Atlantic salmon smolts. Fish fed the diet containing 0.60% Maxi-Gen™ Plus exhibited lower plasma cortisol levels. The villus height, width and apparent surface area of both mid and distal intestines were not influenced by including Maxi-Gen™ Plus in the diet. Statement of relevanceThree experiments assessed the effect of the inclusion of dietary nucleotides fed as Maxi-Gen™ Plus on the stress level, growth performance and intestinal histology of in-season and off-season Atlantic salmon smolts. Increasing the dietary inclusion level of Maxi-Gen™ led to improved hypo-osmoregulatory ability and growth performance with no noted effect on the intestinal histology of Atlantic salmon. This indicates as the dietary inclusion level of Maxi-Gen™ increased from 0.05% to 0.60%, so did the “smolt window,” or period of time when the smolts can be transferred from fresh to salt water.