Effects of Dietary Natural Zeolite (Clinoptilolite) on Growth and Some Blood Parameters of Rainbow Trout (Onchorynchus mykiss, Walbaum 1792)

Abstract

This study was performed to evaluate the effects of adding different levels of natural zeolite (clinoptilolite) to juvenile rainbow trout (Onchorynchus mykiss) diets about growth performance and some biochemical blood parameters. The experimental system was designed as a semi-recirculating aquaculture system and 20 rainbow trouts which weigh 7.91±0.03 g distributed randomly for each tank (300 L). Fish were fed to apparent satiation with diets containing 45% crude protein and 14% crude fat for 70 days which included no zeolite (Control), 0.5% zeolite (Z05), 1% zeolite (Z1), 2.5% zeolite (Z25) in triplicate. Finally, blood samples were collected from all fish tanks to analyze some biochemical blood parameters like cholesterol, triglycerides, LDL, HDL, and VLDL. At the end of the experiment, Z25 group showed negative results in final body weight, weight gain, and specific growth rate (p<0.05). Although Z05 group showed no significant difference, it showed the best results in final body weight, weight gain, specific growth rate, feed intake, feed conversion rate, and protein efficiency. In terms of blood parameters, all the groups had similar values with no significance (p>0.05) compared to the control group. As a result, there was a tendency towards decreased growth and feed utilization due to the addition of zeolite higher than 1% in diets. It could be concluded that limited usage of clinoptilolite in rainbow trout diets might have beneficial effects on growth parameters.