Abstract

The quality of the algae Ascphyllum nodosum was assessed as a growth promoter in the breeding stage of Rainbow Trout (Oncorhynchus mykiss) and its immunostimulant effect with regard to fungal diseases as the Saprolegnia sp. 6000 fingerlings of 77 days of age were used, with an average weight of 0.15 g, distributed under a DCA. For the analysis of the results, it was applied the analysis of variance and separation of averages (Duncan to p<0.05), orthogonal comparisons and chi square. The seaweed Ascophyllum nodosum added as nutritional supplement in the growth stage with a level of 2% and 98% of concentrated food was the one that reached the best zoo technical and economic results: initial weight 0.84 g, daily weight gain 0.30 g, final weight 34.60 g., nutritive conversion 0.19, mortality 4.60%, and the cost of production per kilo of meat is $35.24. Regarding the mycotic challenge (fungus Saprolegnia sp.), the administration of the seaweed Ascophyllum nodosum on the percentages of 2%, 2.5% and 3% as nutritional supplement, provided resistance to the fingerlings.