Difference in the health effects of macerated and pressed peanut oils (Arachis hypogaea, L.) on stressed rainbow trout (Oncorhynchus mykiss)

Generally, peanut (Arachis hypogaea, L.) products have been used as alternative feed additives in trout farming due to their nutritional properties. The maceration process ensures that fat–soluble substances pass into the oil more. It was thought that the application with enriched oil will give different results. Two experimental diets, macerated oil of peanut (MOP) and pressed peanut oil (POP) were used under high stocking density. The trial was studied on antioxidant parameters, hematological parameters, nitro blue tetrazolium (NBT) activity and proximate composition of rainbow trout (Oncorhynchus mykiss) for 21 days. It was determined that the highest dry matter content (22.33%) and moisture content (77.79%), it was the lowest ash content (1.17%) and relatively low fat content (5.01%) in POP group. This suggested that the POP group had a higher concentration of dry matter, potentially indicating a higher overall nutrient density. In blood parameters, it was determined that mean corpuscular volume (MCV) (121.54 ± 4.30), platelet (PLT) (25.33 ± 3.68), NBT (1.407 ± 0.382) and lymphocyte (LYM) (93.66 ± 1.17) levels of the MOP group and granulocyte (GRAN) (2.15 ± 0.13) level of the POP group were different compared to the control group (P<0.05). In terms of antioxidant parameters, glutathione peroxidase (GPx) (15.585 ± 2.236), superoxide dismutase (SOD) (17.691 ± 2.250) and catalase (CAT) (12.874 ± 0.620) activities of the POP group and malondialdehyde (MDA) (9.169 ± 0.238) level and glutathione reductase (GR) (12.085 ± 1.034) activity of the MOP group were determined to be different compared to the control group (P<0.05). The results reveals that use of antioxidants (MOP) is an effective way of getting the best result in terms of the lipid peroxidation mechanism and blood production in rainbow trout under high stocking density. It was thought that the amount of oil–soluble antioxidant substances may increase with the maceration method and have a higher effect on the parameters.