Beyond ancestral diet trends, all domesticated pet food formulation revolves around supplying necessary or beneficial nutrients that companion animal bodies evolved to use. For domesticated dogs, that inherited dietary predilection may have been influenced by what was not eaten by humans, such as scraps, leftovers and pests. What exactly did those Ur-dogs scrounge from humans? Likely anything the canines could get, judging by modern dogs. Eating what even unfussy hunters and gathers eschewed, such as rodent eyes, may have provided sources of vital nutrients to dogs during domestication, including omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), along with omega-6 fatty acid alpha linolenic acid (ALA).
“It would be pure speculation as to where they might have achieved those nutrients during their evolution/domestication from wolf to domestic dog,” Dr. Greg Aldrich, pet food program coordinator at Kansas State University, wrote in an email. “Based on my reading and some speculation, there were probably several routes by which these fatty acids could come into their diet.
”For the longer chain EPA and DHA, these are more concentrated in the eyes, nervous and brain tissues.”
“It may have been through scavenging from the refuse of humans' food waste. Canids are also known for scrounging for food and consuming a wide array of items, including grass, berries, elimination products from rodents and other small mammals. Most plant sources have some small amount of ALA. The ALA can be bioconverted into EPA and DHA, albeit very slowly. But, possibly this was sufficient to meet their minimum needs.”
“Linoleic acid and linolenic acid are common in plant oils, arachidonic acid is only present in animal-based ingredients,” Dr. Kelly Swanson, University of Illinois at Urbana-Champaign animal nutrition professor, wrote in an email.
Omega-3 and -6 fatty acids from prey items
Prey or scavenged items would have provided most of the dogs needs for the essential fatty acids, Aldrich said. In these animal remains, deposits of fats around the gut would have provided some ALA. For the longer chain fatty acids EPA and DHA, the eyes, nervous and brain tissues would have held the highest concentrations.
“Consumption of those organs in their prey probably provided sufficient quantities for health maintenance,” Aldrich said. “These are components that are not found in modern byproduct ingredients like meat and bone meal or poultry meal. Some of the lamb meal (fat within) contains some ALA. Most grazing animals will have accumulated some ALA from the forages they consume. So, meat/fat/protein meal would be a source as well.”