Nutrients

Hello, this post will start off the first module of our Veterinary Nutrition and Animal Toxicology unit. We'll take a look what a nutrient is, some important definitions, the 8 categories of feedstuffs as well as the variation in the proportions of nutrients in different feedstuffs.

What is a Nutrient?

A nutrient is defined as any chemical compound that is required for normal reproduction, growth, lactation, or maintenance of life processes. Sometimes we can get compounds that are not required by the body but are still useful to it. This includes things such as starch and fibre which aren't absolutely essential but are still helpful to the body. The major nutrients that can be found in food include proteins, fats, carbohydrates, minerals, vitamins and water. 

Energy

An animal's diet needs to supply it with both nutrients and energy. Energy is stored in the chemical bonds that are present in food and this energy is released after digestion, absorption and intermediary metabolism (see the Biochemistry posts for more info on these processes). Energy isn't strictly considered a nutrient but it is a main component in food. It is the "ability to do work" and allows normal reproduction, growth, lactation and the maintenance of life processes to occur.

Important Definitions

Before we continue on with the rest of this nutrition unit, it is helpful to understand the meaning of a few terms:

• Food: is an edible material that provides nutrients to the animal
• Feed: is used to describe animal food
• Feedstuff: this is any material that is made into or used as feed.  There are 8 categories:
1. Dry forage ( hay and pasture)
2. Pasture, range plants, feeds that are cut and fed green.
3. Silages
4. Energy concentrates (cereal grains, fats, and oils)
5. Protein supplements
6. Minerals
7. Vitamins
8. Additives
• Diet: this is a mixture of feedstuffs which supply nutrients to the animal.
• Ration: a daily allocation of food. 

 Variation

The amount of a certain nutrient that is contained in a feedstuff is variable between ingredients as well as within ingredients. For example young grass can be composed of 5% protein but soybean meal can contain 46.7% protein. In addition, the protein content of oaten hay can range from 4 - 12.5%.

Rations need to take into consideration this variation to ensure that the animal receives the required amount of nutrients and energy.

Feedstuffs that originate from plants generally contain a higher amount of carbohydrates than animal-based foods. However, the composition of plants is more variable than between animal species.

The proportions of nutrients will change in an animal with age. As the animal gets bigger, fat content increases and water content decreases. 


That's it for this post, see you next time :)