Crude Protein
Why do rabbit foods have different amounts of protein and how much do they really need?
Is an 18% crude protein rabbit food worth the extra cost?
To answer this question here is a tip on protein quality: You can tell if your rabbit food has excess or poor quality protein simply by feeding it…well, actually after you feed it, because:
Poor quality protein
causes your rabbit to stink
1. The smell of ammonia comes from wasted protein and, although it is impossible to be “ammonia free,” excessive levels of it are obvious indicators that protein in the feed is not getting used. Protein is expensive! That is why rabbit food that is higher in protein costs more. However paying extra for the added protein doesn’t guarantee that it is balanced and will actually provide any benefits. In fact it could cause more problems.
2. Excess unbalanced and undigested protein produces ammonia in the caecum. This will change the pH favoring bad bacterial growth which reduces feed efficiency and increases the likelihood of diarrhea.
Yucca root: Some rabbit foods try to cover up excess ammonia with the use of secondary plant metabolites like saponins from yucca root because they bind to ammonia. However, using Yucca root extract is like using a band-aid to cover up the problem. A balanced rabbit food will not need yucca root extract. Besides, alfalfa already naturally contains enough saponins for rabbits.
Protein is made up of individual building blocks called amino acids. These building blocks are linked together in a string-like fashion.
While building a protein many of these amino acids can be converted by the body into the form that it currently needs. However, there are certain “essential” amino acids that are called so simply because they can’t be converted and must be obtained in the diet in their natural form.
It is important that these essential amino acids are obtained in a certain ratio to each other because these building blocks are not “stored” for later use like fats and carbohydrates. Think of it like a puzzle... if you were missing a few pieces you would need to buy a whole new puzzle just to get those few missing pieces and then you would have to throw away everything else.
For example, after a protein is made from a pool of amino acids (a completed puzzle) it can be used to serve a particular purpose (like a digestive enzyme, a muscle fiber, or a part of the kidney or liver) . If an essential amino acid is in short supply (a missing puzzle piece) then that protein might not get made. This compromises the health of the rabbit.
Putting it all together... if a single essential amino acid is deficient or limiting in the diet then it reduces the usefulness of all the rest of the protein.
Any protein that is not used will have to be metabolized (burned like a carbohydrate) resulting in even more ammonia production!The rabbit would have to eat more food to just to get the limiting amino acid (and waste the rest of the nutrients!).
Furthermore, balancing the protein of rabbit food should be according to the digestibility of the protein and each individual essential amino acid. Currently there are three ways scientists measure the digestibility of amino acids. Sherwood Forest Rabbit food is balanced according to the "true ileal digestibility" (the best way) of all the 11 essential amino acids.
Balancing the “amino acid profile” of rabbit food will make the protein more efficient, improve the feed conversion ratio, and will reduce ammonia production along with the subsequent organ stress.
"Dry matter" vs. "As fed" values for protein and other nutrients listed on the feed label:
Is an 18% crude protein rabbit food worth the extra cost?
To answer this question here is a tip on protein quality: You can tell if your rabbit food has excess or poor quality protein simply by feeding it…well, actually after you feed it, because:
Poor quality protein
causes your rabbit to stink
1. The smell of ammonia comes from wasted protein and, although it is impossible to be “ammonia free,” excessive levels of it are obvious indicators that protein in the feed is not getting used. Protein is expensive! That is why rabbit food that is higher in protein costs more. However paying extra for the added protein doesn’t guarantee that it is balanced and will actually provide any benefits. In fact it could cause more problems.
2. Excess unbalanced and undigested protein produces ammonia in the caecum. This will change the pH favoring bad bacterial growth which reduces feed efficiency and increases the likelihood of diarrhea.
Yucca root: Some rabbit foods try to cover up excess ammonia with the use of secondary plant metabolites like saponins from yucca root because they bind to ammonia. However, using Yucca root extract is like using a band-aid to cover up the problem. A balanced rabbit food will not need yucca root extract. Besides, alfalfa already naturally contains enough saponins for rabbits.
Protein and its Building Blocks
Protein is made up of individual building blocks called amino acids. These building blocks are linked together in a string-like fashion.
protein is a chain of amino acids
Dietary protein is a pool of amino acids or puzzle pieces that are put together in new ways to make enzymes and other proteins that your rabbit needs.
A complete protein has a specific 3 dimensional structure that gives it a special function.
A diet deficient in any specific amino acid is a diet with missing "puzzle pieces"
Furthermore, balancing the protein of rabbit food should be according to the digestibility of the protein and each individual essential amino acid. Currently there are three ways scientists measure the digestibility of amino acids. Sherwood Forest Rabbit food is balanced according to the "true ileal digestibility" (the best way) of all the 11 essential amino acids.
Balancing the “amino acid profile” of rabbit food will make the protein more efficient, improve the feed conversion ratio, and will reduce ammonia production along with the subsequent organ stress.
"Dry matter" vs. "As fed" values for protein and other nutrients listed on the feed label:
- Published research and animal nutritionists usually make animal feed formulations based upon a "dry matter" basis (without moisture/water).
- Laws dictate that feed labels report values on an "as fed" basis (with moisture).
- What does this mean? A rabbit food that reports a minimum of 15% protein on the feed label (as fed) actually contains over 17% protein on a "dry matter" basis... which is what scientists would report in their publications.
- A truly balanced rabbit food doesn't require more than a 15% protein content (on a dry matter basis), especially when balanced with the proper amount of energy.
- The source of the protein will also determine its digestibility and whether or not the rabbit is even able to use it. Some protein sources like soybean meal have higher levels of what is called a “trypsin inhibitor” which is a molecule that inactivates protein digestive enzymes. This prevents the rabbit from digesting some of the protein before it gets to the caecum where bad bacteria use it like candy.
- You can tell the efficiency of the protein in the rabbit food mostly by the amount of ammonia your rabbitry produces when you feed it.
