A new study has found that chemical and environmental contaminants at home and diet could be responsible for decreasing fertility of the men and the domestic pet dogs living in the house. The results of the new study were published in the latest issue of the journal Scientific Reports.
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Researchers at the University of Nottingham say that over the last few decades there have been concerns regarding loss of fertility and 50 percent reduction the sperm quality worldwide. They also noted that the sperm quality of pet dogs at home has also declined by around 30 percent over time. This raised the question of a common factor present at home that could be blamed.
The team started their study by checking on the effects of two specific chemicals called the common plasticizer diethylhexyl phthalate or DEHP and an industrial chemical polychlorinated biphenyl 153 (PCB153). The DEHP is found across various items at home including carpets, floors, clothes, wires, toys, upholstery etc. PCB153 is found in food items but has been banned around the world. The team collected sperm samples from donor men and stud dogs living in the same region of the UK. They noted that when the levels of the chemicals were higher in the environment, there was a decline in sperm quality of both men and the dogs.
Study leader Associate Professor and Reader in Reproductive Biology at the School of Veterinary Medicine and Science, Richard Lea, said in a statement, “This new study supports our theory that the domestic dog is indeed a 'sentinel' or mirror for human male reproductive decline and our findings suggest that man-made chemicals that have been widely used in the home and working environment may be responsible for the fall in sperm quality reported in both man and dog that share the same environment.” He added, “Our previous study in dogs showed that the chemical pollutants found in the sperm of adult dogs, and in some pet foods, had a detrimental effect on sperm function at the concentrations previously found in the male reproductive tract. This new study is the first to test the effect of two known environmental contaminants, DEHP and PCB153, on both dog and human sperm in vitro, in the same concentrations as found in vivo.”
Rebecca Sumner, a PhD scholar, who conducted the experimental parts of this study explained, “In both cases and in both subjects, the effect was reduced sperm motility and increased fragmentation of DNA. We know that when human sperm motility is poor, DNA fragmentation is increased and that human male infertility is linked to increased levels of DNA damage in sperm.” She added, “We now believe this is the same in pet dogs because they live in the same domestic environment and are exposed to the same household contaminants. This means that dogs may be an effective model for future research into the effects of pollutants on declining fertility, particularly because external influences such as diet are more easily controlled than in humans.”
Professor Gary England, Dean of the School of Veterinary Medicine and Science and Professor of Comparative Veterinary Reproduction, in his statement said, “Since environmental pollutants largely reflect a Western way of life such as the effects of industry, the chemicals present in the environment are likely to depend on the location. An important area of future study is to determine how the region in which we live may effect sperm quality in both man and dog.”