Effects of High Level Dietary Starch on Growth Performance, Some Blood Parameters and Intestinal Bacteria of Rainbow Trout (Oncorhynchus mykiss)

This study was carried out to determine the effects of the inclusion of high level of potato starch (27%) on growth performance, blood parameters and intestinal bacteria of rainbow trout, Oncorhynchus mykiss. A 60-day feeding trial was carried out on triplicate groups of 180 fish (mean ± standart devision =17.03 ± 2.68) in 140-L fiberglass tanks. There were no significant differences in haematological variables such as red blood cell count, hematocrit ratio, hemoglobin concentration; in immunological variable such as respiratory burst activity, and in serum biochemical variables such as total protein, albumin, globulin, triglyceride, cholesterol, and glutamic-pyruvic transaminase of fish fed experimental diets. However, 27% potato starch supplementation negatively affected growth performance (FCR, SGR and weight gain), some immunological parameters (lysozyme and myeloperoxidase activities), and some serum biochemical variables (glucose, lactate dehydrogenase, glutamic oxaloacetic transaminase, alkaline phosphatase). In addition, the total counts of bacteria and lactic acid bacteria in the 27% potato starch supplementation group was found to be significantly higher than the control group (p<0,05). The results of the study revealed that the supplementation of high level of potato starch (27%) in aquafeed has been found to cause undesirable effects on rainbow trou