Comparative Study on Albino and Pigmented Rainbow Trout (Oncorhynchus mykiss): Growth, Non-Specific Immunity, Disease Resistance and Related Gene Expressions

Abstract

In this study, a comparison has been made between the albino (AA), normal pigmented (PP), mixtures (Mix), and their crossbreds (AP and PA) of rainbow trout, in terms of growth performance, non-specific immune system parameters, mRNA relative expression levels, and disease resistance. Regarding the non-specific immune system parameters that were examined, the albino group (AA) showed the highest values of lysozyme, NBT, and IgM levels, while the normal pigmented (PP) group exhibited the lowest values. The lowest mortality rate was observed after the challenge test in the AA group (16%), followed by PA (30.66%), Mix (32.00%), and AP (36.00%), with the highest mortality rate recorded in the PP group (52.00%). The results obtained from experimental research have been confirmed through molecular analyses. The expression level of IL-8 showed the highest level in the AA group (6.05 ± 1.95^a), followed by PA (4.44 ± 1.60^ab), Mix (3.04 ± 0.72^bc), and AP (1.29 ± 0.23^c) groups compared to the PP group (1-fold). There was no statistical difference among the groups in terms of growth performance (except for specific growth rates and final weights) and IGF-1 mRNA expression levels. In conclusion, the study suggests that albinism does not have a detrimental effect on rainbow trout. In addition, observation of a strong non-specific immune system in albinism could promote more efficient and sustainable aquaculture.