The effect of clinoptilolite as a feed additive on selected rainbow trout ( Oncorhynchus mykiss ) haematological and biochemical parameters, before and after stress treatment

Abstract

Clinoptilolite, a natural zeolite, has been added to animal diets to enhance various production parameters. We conducted a feeding experiment, with subsequent stress treatment (lowered oxygen levels), to assess its effect on haematological and biochemical parameters in rainbow trout (Oncorhynchus mykiss). Our results indicated no significant effect of up to 6% clinoptilolite addition to the diet. Stress induction lowered MCHC, Fe and TAG values, but resulted in higher concentrations of ALP, GLUC and Mg. Cl and Na ions showed a divergent trend, with Cl ions decreasing with increasing clinoptilolite concentration before stress, but increasing continuously after stress, whilst Na concentrations decreased after stress at high clinoptilolite concentrations. Though many factors influence the stress response, we showed that lowering oxygen levels can significantly affect both haematological and biochemical parameters in rainbow trout.