Against the background of declining semen quality and rising incidence of undescended testes (Cryptorchidism) in humans associated with exposure to environmental chemicals (ECs) during development they report that “a population of breeding dogs exhibit a 26 year (1988–2014) decline in sperm quality and a concurrent increased incidence of cryptorchidism in male offspring (1995–2014). A decline in the number of males born relative to the number of females was also observed.Researchers Richard G. Lea and associates published on Aug 9th, 2016, a report entitled Environmental chemicals impact dog semen quality in vitro and may be associated with a temporal decline in sperm motility and increased cryptorchidism. (In Nature, Scientific Reports 6, Article number: 31281 (2016) doi:10.1038/srep31281). ECs, including diethylhexyl phthalate (DEHP) and polychlorinated bisphenol 153 (PCB153), were detected in adult dog testes and commercial dog foods at concentrations reported to perturb reproductive function in other species”.
Food wrappers and other industrial and commercial products from firefighting foam to water-repellant clothing contain poly-and perfluoroalkyl substances, or PFAS, detected in drinking water and having endocrine disrupting and carcinogenic properties.
Estrogen-mimicking, endocrine-disrupting chemicals have become virtually ubiquitous in many of the foods we consume, some of which, along with their byproducts, are included in most manufactured pet foods; in the can-linings of moist, and in plastic bagging and wrapping of dry and semi-moist foods. Plastic may also be processed into the manufactured food along with discarded meats, packaging and all.
Dioxins, predominantly released as byproducts of human activities such as incineration and fuel combustion, are a most potent class of carcinogens and endocrine disruptors. They are ubiquitous in the environment, and from the soil and vegetation undergo bioaccumulation in the fat (tallow) of cattle, and sea foods, especially farmed salmon, which are common pet food ingredients. Their adverse impact on wildlife reproduction and sexual development in several aquatic and terrestrial species has been well documented.
Other estrogen-mimicking and endocrine disrupting contaminants of pet (and human) foods include glyphosate and other herbicide residues in corn and other cereals along with phytoestrogens in soy products especially in GMO soy, a widely used pet food ingredient.
Aflatoxin B1—yet another endocrine disruptor-from the mold on corn and other cereals, is often found in dry dog foods which are recalled too late to save many dogs from acute toxicity and death. Aflatoxins, dioxins and other endocrine disruptors, estrogen mimics, carcinogens and obesogens have harmful consequences in extremely low concentrations in the diet over an extended time period with possible synergism operating where one contaminant increases the toxicity of one or more others; and prenatal, epigenetic, developmental effects on the offspring of exposed parents.