Geometric analysis of macronutrient selection in breeds of the domestic dog, Canis lupus familiaris

Abstract

Although many herbivores and omnivores have been shown to balance their intake of macronutrients when faced with nutritionally variable foods, study of this ability has been relatively neglected in carnivores, largely on the assumption that prey are less variable in nutrient composition than the foods of herbivores and omnivores and such mechanisms therefore unnecessary. We performed diet selection studies in 5 breeds of adult dog (Canis lupus familiaris) to determine whether these domesticated carnivores regulate macronutrient intake. Using nutritional geometry, we show that the macronutrient content of the diet was regulated to a protein:fat:carbohydrate ratio of approximately 30%:63%:7% by energy, a value that was remarkably similar across breeds. These values, which the analysis suggests are dietary target values, are based on intakes of dogs with prior experience of the respective experimental food combinations. On initial exposure to the diets (i.e., when naive), the same dogs self-selected a diet that was marginally but significantly lower in fat, suggesting that learning played a role in macronutrient regulation. In contrast with the tight regulation of macronutrient ratios, the total amount of food and energy eaten was far higher than expected based on calculated maintenance energy requirements. We interpret these results in relation to the evolutionary history of domestic dogs and compare them to equivalent studies on domestic cats.

Soybean oil and beef tallow in dry extruded diets for adult dogs

“…As shown by Hewson-Hughes et al (2013), the dietary ratio of protein:fat:carbohydrates [% of ME] preferred by dogs is 30:63:7. Moreover these authors have also demonstrated that dietary fat increases palatability and food intake in dogs.…”

“…As an omnivore with carnivore tendency, the dog prefers high fat diets (Hewson-Hughes et al 2013). Therefore, an evaluation of the properties of different fat sources available for the pet food industry is of major interest.…”

Balancing macronutrient intake in cultured Lytechinus variegatus

“…Studies utilizing the Geometric Framework (GF) model suggest that animals have the ability to adjust foraging and feed intake patterns to fulfill nutritional requirements (Chambers et al, 1995;Dussutour et al, 2010;Felton et al, 2009;Hewson-Hughes et al, 2012Lee et al, 2002;Mayntz et al, 2009;Raubenheimer and Simpson, 1993;Simpson and Raubenheimer, 2012). When presented with food choices, many organisms will self-regulate feed intake in such a way as to reach intake targets for one or more nutrients Simpson and Raubenheimer, 2012).…”

“…Dietary intake targets for protein have been identified across many animal taxa (Chambers et al, 1995;Felton et al, 2009;Hewson-Hughes et al, 2012Lee et al, 2002;Mayntz et al, 2009;Raubenheimer and Simpson, 2003;Solon-Biet et al, 2014;Sørensen et al, 2008). Previous studies indicate that sea urchins will adjust feed intake, presumably to satisfy nutritional requirements (Fernandez and Boudouresque, 2000;McBride et al, 1999;Taylor, 2006;Wallace, 2001 individuals adjusted intake patterns to defend this target regardless of nutrient ratios or feed concentrations.…”

Preference ranking procedure proposal for dogs: A preliminary study

“…These include a single‐bowl monadic test, a two‐bowl forced choice test, and operant testing. Some researchers also utilize the traditional two bowl forced choice test and modify it in order to fit their objective and needs (Fragua, Barroeta, Manzanilla, Codony, & Villaverde, ; Hewson‐Hughes et al, ; Verbrugghe, Hesta, Gulbrandson, & Janssens, ). However, none provides an indication of why a choice is preferred.…”