Paternal exposure to environmentally relevant levels of di-(2-ethylhexyl) phthalate (DEHP) disrupts breeding success and offspring immune health in koi carp ( Cyprinus carpio )

Di-(2-ethylhexyl) phthalate (DEHP), a common plasticizer regarded as prevalent environmental pollutant. Although, the reproductive toxicity of DEHP in aquatic animals are well documented, but its impact on offspring immunity after parental exposure remains unknown. In this study, mature male koi carp were exposed to DEHP at three distinct environmentally relevant levels (1, 10 and 100 μg/L) for 150 days. Pairing of exposed males with untreated females at post-exposure significantly lowered the fertilization, hatching and larval survival rates. Further, the larvae of each group were reared separately up to 40 days in control condition to evaluate the transgenerational immune effects of DEHP. The length gain, weight gain and specific growth rate were reduced significantly in the fingerlings of exposed groups. Histological investigations revealed the cellular structural impairment in liver and kidney tissues of the paternally treated fingerlings. The levels of immune and stress-response biomarkers, such as HSP70, HSP90, IgM and cortisol were fluctuated in the fingerlings of exposed groups. The mRNA study of immune-related genes (IL1β, IL10, IL8, TNFα, TLR5, iNOS, TGFβ, C3, NF-κB and MyD88) exhibited differential expression patterns in the paternally impacted fingerlings. Findings of this study reveals that DEHP exposure not only affect the exposed individual, yet also the future generations.