In this part you will find information on phosphorus and digestible/available phosphorus content of the different feed materials
In case of ruminants including roughages. We have also included a system which enables you to calculate the P-requirements of the different animal species, simply by filling in production parameters in an Excel sheet. In case of ruminants we have also included information on Magnesium in ruminant nutrition.
Mineral requirements for ruminants depend on stage of pregnancy, bodyweight, milk yield and composition (milk contains an average of 1.2 and 0.9 g/l calcium and phosphorus respectively and colostrum can contain twice these levels).
A complicating factor is the fact that mineral requirements need to be balanced for the complete lactation cycle. Minerals mobilised from the bone during early lactation must be replenished towards the end of the cycle to maintain cow health and performance. However, most systems do not account for this phenomenon. Current nutritional recommendation systems refer to an "average animal" under "normal" feeding conditions and in a state of good health. Recent improvements in animal production means that "normal" conditions might be sometimes outdated. But also there can be a substantial variance around this "average" animal.
The factorial method is the most efficient and reliable method to assess mineral requirements. This method is based on establishing estimates for net requirements for maintenance, growth, pregnancy and lactation together with a true absorption coefficient resulting in dietary requirements for the mineral elements.
To arrive at practical allowances a safety margin is normally included. This safety margin usually allows for the variation within flocks or herds, fluctuations in feed intake and in feed composition.
Maintenance + Pregnancy + Growth + Lactation
Dietary Requirement = ----------------------------------------------------------
Mineral element allowances (g/d) of a lactating cow (600 - 650 kg BW, 35 kg milk/d)
|AFRC (1991); UK||85||73 - 93||39|
|NRC (2001); USA||144||59 - 69||45|
|GFE (1992); DE||130||80||35|
|INRA (1988; 2002); FR||159||74|
|CVB (2002); NL||91||62||41|
The system offers both a digestible phosphorus coefficient and digestible phosphorus content dP) for each feed material. In this way, it gives you the choice of either using the dP content of a feed material or calculating the digestible-P content of a feed material using the dP coefficient and your own Total-P content. To accommodate countries where local recommendations do not exist, we also have included a chapter, which sets out some Digestible-P allowances for pigs.
A simple tool for implementing the digestible phosphorus system
The digestible phosphorus system developed by Aliphos is an easy to use system, developed for nutritionists, feed formulators, researchers and others involved in the composition of feed for animals, particularly pigs. Our goal with this program is to provide the feed formulator with a simple tool for implementing the digestible phosphorus concept. It will enable him to make a better use of natural resources, therefore, improving profitability in an ecologically sound way.
Justification of the figures
The values which appear in the different tables (total-P content, digestible-P %, and digestible-P content) have been selected by the technical staff of Aliphos. For each feed material as many as possible have been collected from published tables and literature. The most appropriate one was then selected, either as the most likely one or in case of many different values as an average value. In some cases the value reflects a personal opinion of our staff. The value published by Aliphos corresponds in this way to a rather significant number of samples. This improves the impartiality of the figures.
You can contact us for more information at: firstname.lastname@example.org
A simple tool for implementing the digestible phosphorus system
The digestible phosphorus system developed by Aliphos is an easy to use system developed for nutritionists, feed formulators, researchers and others involved in the composition of feed for animals, particularly poultry.
The program's objective is to provide the feed formulator with a simple tool for implementing the digestible phosphorus concept. This will allow for better use of natural resources, improving profitability in an ecologically sound way.
For more information please contact us at; email@example.com
The use of Aliphos Feed phosphates
It is not always easy to gather information on phosphorus digestibility of the feed materials used in aquaculture.
There are numerous reasons for this, most notably the fact that there are many species with different intestinal and digestive systems. Certainly also in the past, due to the high use of fish meals, phosphorus or digestible phosphorus supplementation was not an issue.Therefore, Aliphos has carried research into the phosphorus digestibility of its feed phosphates. Because of the vast number of aqua cultural species, a selection has been made and these trials were carried out with trout and shrimps.
The role of phosphorus in the nutrition of fish
Minerals including phosphorus are essential for our bodies, equally so for fish. However, fish can obtain most of the minerals they require (calcium, sodium, potassium) directly from the water (especially in sea-water). Phosphorus, however, is one of the essential minerals that must be supplied via the diet. Phosphorus (together with calcium) is a structural component for bones, teeth and scales. In addition, it plays a role in several metabolic processes. Reduced growth rate, reduced feed efficiency and bone deformities are the most common signs of (digestible) phosphorus deficiency.
Phytase (myo-inositol hexaphosphate phosphohydrolase) is an enzyme that is capable of catalysing the hydrolysis of phytate or phytic acid (phytate is a salt of phytic acid hexaphosphoinositol: C6H18O24P6 containing 28% phosphorus) to (inorganic) phosphate and lower phosphoric esters of myo-inositol. It releases phosphorus, making this available for absorption and utilization by monogastric animals and thereby reducing phosphorus excretion.
Phytase a phosphorus source for monogastric animals
Phosphorus (P) consumed by animals is partly excreted in the manure. A major contributor to this is phytic acid, found in vegetable feed materials, which binds 60% - 80% of the total phosphorus present. Phytate-bound phosphorus is not available to monogastric animals, as they have insufficient intestinal enzymes to digest it effectively. Phytase is thus capable of releasing phytate-bound phosphorus and making it available to monogastrics. Commercial phytases are based on different genetically modified microbial strains, giving different levels of efficacy, and are available in several physical formulations.
Molecular structure of phytic acid (from Graf, 1986)