Benefits of Higher Fat Diets: Part 3, Structural and Functional Changes
Higher fat diets are typically beneficial from an efficiency and performance point-of-view, as I wrote about in part 2 of this blog series. Often, the total amount of feed consumed by an animal can be reduced slightly, while performance (output of meat, milk, eggs, etc.) can be maintained or increased. The result is an increase in feed efficiency, and feed costs represent roughly 70% of total input costs.
It’s also important to note that “higher fat” refers to increases in dietary fat and/or oil content that remain within normal feeding ranges.
So, perhaps it’s best to understand why these changes in feed efficiency occur with the feeding of higher fat diets. As with anything, a fundamental understanding of how something works will allow accurate predictions of future performance following controlled changes – in this case, changes in how you formulate a diet. And, as with any ingredient or diet change, you have to understand how the nutrients contained within will be digested and absorbed in the digestive system.
There is evidence that feeding higher fat diets alters the structure of the digestive system. For example, one study reported that the absorptive surface areas in digestive systems of nursery piglets were increased when different types of fats were fed (soy and coconut oils). The study also noted that the responses were different when the fats were either fed individually, or as a mixture.
And, as the old saying goes, “structure predicts function”, so an increase in absorptive surface area should translate to more absorptive function. Based on some work I did, this is indeed the case. Pigs fed either soy or palm oils, each at increasing levels, exhibited improved amino acid digestibilities, somewhat selectively, and the effects were more predictable and linear for soy than for palm oil. These results are even more remarkable considering that the only protein source I used was soy protein concentrate – already highly digestible. What this means is that, for every unit of soy oil increase in the diet, the digestibilities of amino acids should increase at an expected rate.
The purpose of this blog series is to highlight the benefits of higher fat diets. As described here, higher fat diets actually serve to alter the underlying physiology of animals, discussed here using pigs as an example. So, improved efficiencies result because the animals are, in fact, physically different when fed higher fat diets.
Other benefits will be discussed in upcoming blogs and formulation strategies will conclude this blog series.