Chromosome instability in lymphocytes of Friesian cows naturally exposed to dioxins being raised close to a metallurgic factory area in southern Italy

Dioxins (PCDDs, PCDFs and DL-PCBs) are a large family of congeners that are considered highly toxic and are reported to be teratogenic, mutagenic, carcinogenic, immunotoxic and hepatotoxic, also affecting the nervous and reproductive systems. Farm animals are particularly exposed to these chemicals when they are fed with grass produced close to polluted areas such as those located in vicinity of metallurgic factories. Cytogenetic tests can be very useful to check genetic damage occurring to domestic animal cells exposed to these chemicals. Fifty-two randomly selected Italian Friesian cows (Bos taurus, 2n = 60) from two farms located in the vicinity of and (as a control) far from the a metallurgic industrial area underwent cytogenetic investigations to ascertain possible differences in their chromosome fragility. One farm was under legal sequestration due to the presence in the milk mass of higher mean values of dioxins (24.78 ± 3.19 pg g−1 of fat as sum of PCDD + PCDF + DL-PCBs as WHO-TEQ (World Health Organization-Toxic Equivalent Quantity), with DL-PCBs being the main chemical component) than those permitted (5.5 pg g−1 of fat as WHO-TEQ). Cytogenetic analyses, performed by using both the chromosome abnormality (CA) test (chromosome and chromatid breaks) and sister chromatid exchange (SCE) test, revealed a significantly (p < 0.01) higher chromosome fragility in cells of exposed cows (26 cows) compared to those of the control (23 cows).