Enzyme Solutions for Poultry Diets

The matrix value of individual or multi enzymes when given by the enzyme producer can be depended when the producer company is well trusted.

Hello all, I always argue that enzymes are not energy providers in animal feed. To use the famous "matrix values" of the enzyme products that all enzyme providers give to the nutritionist you have to understand where this is coming from. For phytases the phosphate liberated is the main effect but energy comes from the reduction of the antinutritional effect of phytate IP6. The matrix value depends on the ability of the enzyme to breakdown IP6 before it binds with calcium, protein and starch. Also true, more phytate you have more active phytase you will need to reduce these antinutritional effects. So we should measure the phytate present in the final feed, to correlate as well with the "matrix value".
For "carbohydrases" (enzymes that degrade carbohydrates) the effects are more complex, so you have to analyze each enzyme individually. Amylase breaks down starch and should be used to complement the endogenous amylase from the animal, the matrix value will depend on the age of the animal and the diet composition (characterization of the starch is important to understand this). Also, it could be used to control glycemic index in swine if you use less digestible starch (starch from peas is a good example) that could be degraded by the exogenous amylase at the distal jejunum.
Finally, fibre degrading enzymes such as xylanase glucanase and mannanase. All depend on substrate concentration, antinutritional effects they solve and prebiotic effects. These are quite long so they should be discussed in a separate discussion.
And last but not least proteases, the main effect is to make protein more digestible, so the matrix value should be applied on the digestibility of the raw material or final protein. One misconception is to do this directly to the amino acids. Proteases rarely cleaves protein to that degree, most often they will produce polypeptides. This is not a bad thing, in humans polypetides (from animal origin) have been found to boost the immune system. However, as far as I know, there is no research in this area for monogastric animals.

Finally my conclusion: only apply the matrix value when you understand where is comming from


Sorry the long comment.

Dr. Luis, I fully agree with your consideration that changes in the microbiota, favoring the animal, is an important effect of enzyme action. I even think that this aspect should always be considered when presenting articles discussing the effect of enzymes on animal performance. Congratulations.

Dear Lokare,

For the proper application of phytase one needs to know the matrix values of the product, the phytic P levels in the feed and the goal of the production: performance or cost savings.

For sure enzyme responses are non-linear but in the range, we test them in animal nutrition they occasionally appear linear. I think it is crucial to also examine available/reactive substrate concentration when interpreting enzyme response. Systems may be saturated with the substrate in which case enzyme responses may be exaggerated across a wide range of inclusion concentrations, or they may be saturated with enzyme (low substrate concentrations) in which case the enzyme effects may reach a plateau very quickly. Relative substrate/enzyme concentrations should be quantified as often as practically possible before concluding on optimum doses. The next moving part is the limiting nutrients in the diet and which biological response you want to measure as an indication of enzyme value e.g. FCR, uniformity, digestibility, bone ash, etc. In the enzyme domain we have not been as consistent as we should have been in measuring and reporting these points in a systematic way.

I think everyone in this discussion made good comments. It seems to me that all that is needed is an underlying theory to fit all the various pieces into. This is the same for phytase and all the other enzymes:
First, it should be accepted that responses to enzymes follow Michaelis-Menten kinetics. Enzymes do not give linear responses. This was very nicely illustrated by Shirley and Edwards, Jr. (Graded Levels of Phytase Past Industry Standards Improves Broiler Performance, 2003 Poultry Science 82:671–680). Ignoring this approach, animal nutritionists seem absolutely fixated with the linear programming least-cost paradigm of feed formulation. They have just got to find a single number for everything in their feed formulation problem. A good metaphor? Round pegs into square holes? They want to drive in screws, but their only tool is a hammer? Animal nutritionists tend to like biology much more than mathematics. Our brains like to work with straight lines in two dimensions. But the linear programming approach of finding one number to put in a matrix just doesn’t work in this case: “However, this approach is flawed from the economic perspective because it implicitly assumes that there is a single relative value of the sources, regardless of the cost of feed components and the price of live birds” (Vedenov & Pesti, An economic analysis of a methionine source comparison response model, 2010 Poultry Science 89:2514–2520).
Second, once it is accepted that the responses are not linear, it should be a simple matter of applying production economic theory to the curves to find economic optimums (Pesti & Vedenov, An economic comparison of several models fitted to nutritional response data. J. Anim. Sci. 2011, 89:3344–3349). Transforming complex equations into economic space is just not what nutritionists want to do. And with ingredient and meat and egg prices changing daily, economic optimums change daily. I am glad I don’t have to explain that relative values are changing daily to a purchasing agent, but such a discussion may prove prudent.
Third, to try to understand the economic implications of the technical problems observed in animal nutrition, my approach was to team up with a very good agricultural economist, in these cases, Dmitry Vedenov. It is not easy to get even agricultural economists to understand the finer points of animal nutrition, like FTU’s. And it is not easy to understand exactly what they mean when they start talking in terms of Greek symbols. But they are really good at solving non-linear problems. With large sums of money at stake in using the right products at the right levels, it may be worth considering involving a professional economist in the decision-making process.

Each phytase has an optimum pH with ftu’s conveying its relative activity under that specific condition. Phytases first act during storage in the crop with pH’s varying between 4-6 over varying durations. This ingests is conveyed into gizzard where pH’s decrease to 2-3 again over varying durations. Phytases of different pH optima continue to function through crop and gizzard only to varying extents. The Ftu units simply approximate expectations of action through highly variable terms of “gastric digestion.” Don’t be surprised with results varying with any defined ftu.