| Summary: | Dioxins and dioxin-like polychlorinated biphenyls (dl-PCBs) are chemical congeners formed as by-products from incomplete thermic reactions, found in the environment because of improper disposal from industrial processes and combustions. Dioxins and dl-PCBs are of human concern, as they are persistent to degradation and bioaccumulates in marine food-webs. Salmon (Salmo salar) is recommended to be a part of the human diet because of healthy marine nutrients including omega-3 fatty acids, but is also one of the main routes of dioxin and dl-PCBs exposure. Dioxins and dl-PCBs which binds to the aryl hydrocarbon receptor (AHR) and elicits toxic responses, are incorporated in the toxic equivalency factor (TEF)-system. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is indicated to be the most potent congener, because of its high binding affinity to the AHR. Earlier research has found that the toxicity of TCDD alters the male reproductive system by disrupting spermatogenesis, thereby reducing sperm quantity and sperm motility, decreasing reproductive organs weights, and causing a delay in puberty. In 2018, the European food safety authority (EFSA) estimated a new tolerable weekly intake (TWI) of dioxins and dl-PCBs in food, reducing it from 14 to 2 pg toxic equivalency quotient (TEQ)/kg body weight/week. Male reproduction was one of the pivotal effects when estimating the new TWI, where the daily exposure in adults should be kept below 0.25 pg TEQ/kg bw/day. The aim of the study was to investigate if continuous doses of TCDD impacts the reproductive system, the spermatogenesis, and sperm quantity in male Wistar HAN rats. In addition, we measured whether inclusion of salmon in the diet could possibly reduce the toxicity of TCDD. Observations made throughout the animal experiment, including body mass development, feed efficiency, haematology tests, and the TCDD-levels in the liver upon sacrifice was analysed to get a wider view of possible effects between the experimental groups. An investigation on male reproduction was ...
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