So what does a dog want to eat?

Having outlined the reasoning behind wanting to establish the instinct macronutrient self-selection of dogs, I will now discuss my research findings. 

The first approach I adopted was to provide a group of dogs essentially with a buffet of different foods to choose from, these were referred to a high carbohydrate, high fat and high protein diets. Over a ten day period, the dogs could eat as much of each diet they wanted, based on which I was able to calculate the targeted protein-fat-carbohydrate content. I found that initially the dogs ate a large amount of dietary fat, with this intake slowly decreasing over time. In contrast protein consumption increased over the study, with carbohydrate intake remaining very low. At the end of the study I was able to determine that the dogs on average received approximately two thirds of their energy from fat and a third from protein. 

Dogs target a dog rich in fat and protein, with only a very amount of carbohydrate

Next, I decided to investigate if a preference occurred when a group of dogs were offered two high carbohydrate diets simultaneously with the same quantity of protein-fat-carbohydrate, but with differences in the main carbohydrate ingredient. After this, the same study was repeated, but this time with two high protein diets. The results showed that no significant dietary preference was detected between the dogs offered the two carbohydrate and then the two protein diets. Interpreting this, highlights that regardless of ingredients used in a diet, the ratio of macronutrient is the crucial factor in palatability. 

The final study I conducted examined protein-fat-carbohydrate content that dogs selected again, however this time extending the self-selection time to 28 days. This was completed using the same approach as in the 10 day initial study, in which variations in fat and protein occurred. By conducting the same study for longer, would therefore facilitate an understanding if macronutrient self-selection stabilises. The findings were that with the exception of the first day, when the dogs consumed a high fat content, the macronutrient intake, was the same as that witnessed in the first study, namely two third of energy sourced from fat, a third from protein, combined with a neglectable amount of carbohydrate. However, one intriguing aspect was that the dogs in my final study essentially decided in one day how much protein-fat-carbohydrate they wanted to eat, while in my initial study there was still macronutrient movement over the ten day feeding trial. Although it remains unclear as to why this occurred, factors such using several different dogs in the first study and variations in ambient temperature (which could have influenced basal metabolic rate), might have had key roles.