You might need to pay more attention to your branch chain amino acid intake!
Muscle is a beautiful thing, be it on your horse or yourself. It provides strength, power, speed and it looks great. It is also very functional, providing stability and balance and a whole host of really important metabolic functions like the storage and utilization of glucose (which for us humans is very important).
Apparently as a human we build muscle until we are about 30 years old, and then we start to lose it… UNLESS we use it! I am not sure of the statistic for horses with regard to when they might start to lose muscle mass, but we have all watched horses turned out for extended periods of time starting to lose their muscle.
So muscles need work to be maintained or built! BUT, they also need the right building blocks to be able to grow.
Building Blocks of Muscle
Muscle is made from protein. And protein is made from amino acids. So to build muscle, a body needs access to the amino acids it needs to put muscle together. Muscle also needs a signal to start building muscle. In other words muscle protein synthesis needs to be switched on before anything will happen.
Back to the amino acids for a minute… There are 20 amino acids. Ten of them we call non-essential amino acids as our bodies and our horses can make them so we don’t pay these a whole lot of attention in nutrition.
The other 10 we call the essential amino acids and these must be provided in the diet. Within this group of essential amino acids there is a group called the ‘Branch Chain Amino Acids’ or the BCAAs (which include leucine, isoleucine and valine). In human muscle BCAAs make up up to 18% of the amino acids in our muscle protein, making them super important when it comes to building extra muscle mass!
But there is more to this story… research in humans and rodents has found that one of the BCAAS, leucine, has a particularly important role with regards to SWITCHING ON muscle protein synthesis. In fact it appears it is almost singularly responsible for doing this.
There are 3 major things needed in order to build muscle in horses:
1. Work! Muscles won’t grow unless they are given work to do.
2. Leucine. This branch chain amino acid switches on muscle protein synthesis.
3. Plenty of the other amino acids. Between work and leucine, muscles are stimulated to grow. So they then need a ready supply of all the other amino acids they need in order to actually grow.