Pit-tagging of Atlantic salmon in family feeding experiments
Today, the traditional way of selecting animals for feed efficiency is through indirect methods such as growth rate, based on the assumption that growth rate correlates with feed utilization. The outcome is faster growing fish, but also fish with a higher feed intake. Thus, overall result need not be increased feed efficiency. A possible direct way to select for feed efficiency is to develop a method to measure nutrient turnover at an individual level and look at genetic variation between families. With the use of stable isotopes in the diet, the absorption and metabolism of different nutrients are traceable. During 2017, we will perform two feeding experiments with distinct families of Atlantic salmon where we will need to pit-tag (passive integrated transponders) all individuals to be able to trace individuals and families during the whole feeding experiment. The PIT-tagging can induce mild stress to fish and will be performed under anesthesia.
Experiment 1: The aim of this experiment is to examine metabolism and turnover of macronutrients in different families of Atlantic salmon. During this trial, we will therefore trace nutrient flow and retention in 120 individual Atlantic salmon from 23 different families (a total of 2760 fish), by using a diet containing stable isotope-labelled molecules. The diet will be formulated according to the requirements of salmon in fresh water stage. Prior to the feeding experiment, each fish will be pit-tagged and a small biopsy will be taken from the fin for genotyping to confirm pedigree relationships of each individual.
Experiment 2: The aim of this experiment is to examine the effect of novel yeast products on growth, health, smoltification and survival during sea water transfer of different salmon families (a total of 1000 fish). After pit-tagging, there will be a pre-feeding phase in fresh-water (NMBU), before transfer to seawater (NIVA, Solbergstrand). All diets will be formulated according to the nutrient requirements of salmon.
Terminal sampling will be conducted in both experiments to register individual growth and to sample different organs to measure nutrient metabolism and turnover. Dissection and sampling of organs will only be done after the fish have been euthanized by an overdose of anesthetics. The data from these experiments will provide vital knowledge that can be used in future optimization of dietary composition of salmon diets and future breeding programs for Atlantic salmon.
Experiment 1: The aim of this experiment is to examine metabolism and turnover of macronutrients in different families of Atlantic salmon. During this trial, we will therefore trace nutrient flow and retention in 120 individual Atlantic salmon from 23 different families (a total of 2760 fish), by using a diet containing stable isotope-labelled molecules. The diet will be formulated according to the requirements of salmon in fresh water stage. Prior to the feeding experiment, each fish will be pit-tagged and a small biopsy will be taken from the fin for genotyping to confirm pedigree relationships of each individual.
Experiment 2: The aim of this experiment is to examine the effect of novel yeast products on growth, health, smoltification and survival during sea water transfer of different salmon families (a total of 1000 fish). After pit-tagging, there will be a pre-feeding phase in fresh-water (NMBU), before transfer to seawater (NIVA, Solbergstrand). All diets will be formulated according to the nutrient requirements of salmon.
Terminal sampling will be conducted in both experiments to register individual growth and to sample different organs to measure nutrient metabolism and turnover. Dissection and sampling of organs will only be done after the fish have been euthanized by an overdose of anesthetics. The data from these experiments will provide vital knowledge that can be used in future optimization of dietary composition of salmon diets and future breeding programs for Atlantic salmon.