The Effects of Nucleotide-Containing Product Maxi-GenTM Plus on Stress Level, Immune-Related Gene Expression, Growth Performance and Intestinal Histology of In-Season and Off-Season Atlantic Salmon (Salmo salar) Smolts During Smoltification and Desmoltification Periods

Abstract

Trials were conducted to determine the effects of dietary nucleotides fed as Maxi-GenTM Plus on stress level, immune-related gene expression, growth performance and intestinal histology of in-season and off-season Atlantic salmon smolts. Twenty-four hour, 40ppt salinity tests were conducted to measure the hypo-osmoregulatory ability. Expression of immune-related genes response to polyIC injection was investigated. Growth performance was evaluated as weight gain, food consumption and FCR. Intestinal structure parameters were determined. Diets contained 0.40 to 0.60% Maxi-GenTM Plus resulted in enhanced growth performance. Hypo-osmoregulatory ability during smoltification gradually enhanced with increased inclusion of Maxi-GenTM Plus from 0.05 to 0.60%, which indicated an extended “smolt window”. Diets contained 0.20 to 0.25% Maxi-GenTM Plus resulted in enhanced anti-viral immune response of fish after polyIC injection. Diet contained 0.60% Maxi-GenTM Plus had lower plasma cortisol level of fish. The intestinal structure was not enhanced by feeding Maxi-GenTM Plus.