EFFECTS OF FEED PROCESSING ON NUTRITIONAL VALUE OF YEAST Saccharomyces cerevisae IN DIETS FOR RAINBOW TROUT Oncorhynchus mykiss
Introduction
Previous research has showed that extrusion processing can yield positive effects on digestibility and growth performance in several fish species (Booth et al., 2002 ; Barrows et al., 2007 ; Venou et al., 2006). As observed in earlier trials performed by Langeland (2014) and Vidakovic et al. (2015), extrusion may have been responsible for the increased availability of nutrients in diets containing yeast that were fed to Arctic charr (Salvelinus alpinus) and Eurasian perch (Percha fluviatilis). The aim of this study was to study the effects of several extrusion parameters on the growth performance and health status of rainbow trout fed yeast containing diets.
Material and Methods
In total, four different diets marked were produced by extrusion using a single feed formulation, while manipulating several extrusion parameters (Table I). Fish, (720 in total) were randomly distributed in groups of 30 in each of the 24 tanks. The experiment lasted for 10 weeks and the fish were weighed at the beginning and the end of the trial. Faeces were sampled by stripping in the end of the experiment for estimation of the apparent digestibility coefficients. Inert marker, TiO2, was added into the diets for this purpose.
Results and Discussion
Results will be included shortly.
References
Barrows FT, Stone DAJ, Hardy RW (2007) The effects of extrusion conditions on the nutritional value of soybean meal for rainbow trout (Oncorhynchus mykiss). Aquaculture, 265, 244-252.
Booth M A, Allan G L, Evans A J, Gleeson V P (2002) Effects of steam pelleting or extrusion on digestibility and performance of silver perch Bidyanus bidyanus. Aquaculture Research, 33, 1163-1173.
Langeland M (2014) Nutrition of Arctic charr (Salvelinus alpinus) and Eurasian perch (Perca fluviatilis) and evaluation of alternative protein sources, Dept. of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala.
Venou B, Alexis MN, Fountoulaki E, Haralabous J (2006) Effects of extrusion and inclusion level of soybean meal on diet digestibility, performance and nutrient utilization of gilthead sea bream (Sparus aurata). Aquaculture, 261, 343-356.
Vidakovic A, Langeland M, Sundh H, Sundell K, Olstorpe M, Vielma J, Kiessling A, Lundh T (2015) Evaluation of growth performance and intestinal barrier function in Arctic Charr (Salvelinus alpinus) fed yeast (Saccharomyces cerevisiae), fungi (Rhizopus oryzae) and blue mussel (Mytilus edulis). Aquaculture Nutrition, 22, 1348-1360.
