Oxidative Stress and Haematological Response in Rainbow Trout (Oncorhynchus Mykiss) Fed With Brewer Yeast (Saccharomyces Cerevisiae) as Nutritional Supplement

Abstract

Production of freshwater fish evolved constantly over the past decades in parallel with increasing the amount of ingredients conventionally used to feed these fish. From the main ingredients, those protein based are the most expensive and increasingly difficult to obtain. Fishmeal demands valuable alternative ingredients to replace it and yeasts seem to offer new protein sources, but not only, acting as probiotics in fish feed. We tested productive and physiological benefits of brewer yeast (Saccharomyces cerevisiae) added 1.5% in standard rainbow trout (Oncorhynchus mykiss) nutrition with Coppens fodder (2 mm granulation) with 45% crude protein (CP) over a period of 45 days, starting at an average live weight of 56.86 gramsin a classical system of breeding. Production parameters as average daily gain (ADG), total live gain (TLG) and feed conversion rate (FCR) but also hematologic and biochemical blood parameters have been evaluated. Yeast fed batch presented higher productive indices but not statistically represented. Significant differences were observed in hematological parameters for hemoglobin, very significant response of yeast fed batch regarding gamma globulins (GGL) level and significant changes were also recorded for total proteins (TP). Significantly lower values for amylase were revealed, while enzymatic profile shown significant differences in alkaline phosphatase (PAL) and creatinine phosphokinase (CPK). Overall, 1.5% of dried brewer yeast added to standard fodder in rainbow trout das led to a better use of feed and a strengthening of immunity.