This is an abbreviation of unit 5 from the Advanced Equine Nutrition course. The complete text, a video, and quiz questions are available with The Horse’s Advocate membership. You can also purchase them separately. Note: Passing the Basic Equine Nutrition Course is required before starting the Advanced Course.

Unit 5 – DNA And Protein Synthesis

The Basics Of Building Proteins

Amino acids are the smaller molecules that make a particular protein when put together in a specific order. Remembering the introductory nutrition course analogy, they are like letters in words; 26 letters make all the English words. So, too, 20 amino acids make all the billions of proteins that operate in the body. Ten must come from food. These are known as essential amino acids. The others form in the body from an essential amino acid when needed. These are conditionally essential. Or, they are made on their own, known as non-essential. Cystine is an example of a conditionally essential amino acid. It forms in the liver by converting the essential amino acid methionine into cysteine and then into cystine. Cystine makes up 24% of the keratin in the hooves.

This concept of protein formation is complex for me. I struggle with thinking billions of proteins exist in every body cell. With the horse being so large, horses have more proteins than humans. We know that eating animals and plants will give us these proteins as humans. This provides us with the amino acids. Yet the muscular horse eats no meat! They are herbivores, obligated to be vegetarians. Yet, in humans, there are successful vegetarian competitive bodybuilders. Let’s look at how to accomplish this.

Individual protein production starts after digestion breaks down the dietary proteins into amino acids. The amino acids of plants, animals, and all other living, carbon-based (organic) beings on Earth are identical and shared. This allows horses to eat plants and then make muscles.

Cells take in amino acids to build proteins. They work like a factory, bringing the materials they need into the assembly plant to produce a product. A blueprint describes all the building processes the factory can make. Line crews use templates made from the blueprint. They determine what part of the process they are responsible for. In biology, the blueprint is called DNA; every cell containing a nucleus has the same DNA. These cells also have RNA, where the templates develop from the instructions of the DNA. Proteins are assembled from the RNA template instructions.

Key Points:

1. Horses eat plant proteins containing the essential amino acids shared between all living things. Horses, or the gut microbes, can make amino acids, too.
2. DNA is the master instruction set for all living things. Only 2% of the nucleotides are used to create the animals we know. This includes us and our horses.
3. DNA is formed with repeating units of four molecules (nucleobases) arranged in a specific order. These are attached to a complex sugar molecule (deoxyribose) to make a nucleotide. The nucleotides are strung together to create a long chain (nucleic acid). They are then paired with another nucleic acid to form the double helix called deoxyribonucleic acid, or DNA.
4. Transcription is copying a small section of DNA code to make a template for protein synthesis.
5. Translation is the use of the template to make the protein.
6. Proteins are reviewed for flaws before being released for use, and if defective, are repaired or destroyed. DNA is also scrutinized for damage and is repaired, or the cell is destroyed.
7. The most common limiting factor to healthy protein synthesis is the lack of amino acids. This issue occurs in horses confined to limited pasture and fed diets with limited varieties of ingredients.
8. Eating excess glucose and exposure to chronic stress also leads to amino acid loss and chronic protein deficiency.
9. Epigenetics signals the expression or suppression of portions of the genetic code. This process helps horses adapt to various environmental pressures.
10. Epigenetic pressure impacts the DNA of the horse. It also affects the mitochondria and the microbes of the body because they have their own DNA. Horse owners must remain aware and adjust the dials (food intake and environmental pressures). This helps maintain energy flux by maintaining the efficiency of DNA expression.