Raw material and nutrient lexicon
Phosphorus
Besides calcium, phosphorus is the most important building material for bones and teeth. In addition, phosphorus compounds perform a variety of functions in the metabolism (substance transformations, production as well as storage and utilisation of energy). Phosphorus metabolism is controlled by the parathyroid hormone (hormone of the parathyroid gland) and by vitamin D. Phosphorus is produced by the parathyroid hormone. Parathyroid hormone mobilises phosphorus from the bones, vitamin D stabilises phosphorus in the skeleton. Phosphorus absorption from the digestive tract (gastrointestinal tract) can be impaired by supplying the animal with calcium, magnesium, zinc or even iron in excess. Vitamin D and organic acids, on the other hand, promote phosphorus absorption. The body compensates for an excess of phosphorus in the feed by lowering the absorption rate and increasing phosphorus excretion. Normal phosphorus utilisation is approx. 50-60 %, whereby there are large fluctuations depending on the type of animal and performance requirements. For example, P utilisation drops from 98 % in sucking young animals to less than 50 % in adult animals. With a physiologically correct ratio of calcium to phosphorus (which varies depending on the animal species), there is no danger of the animal being over-supplied with phosphorus. If there is an undersupply of phosphorus, deficiency symptoms such as poor appetite, fertility problems, soft bones and other metabolic disorders can occur.
In the case of phosphorus, a distinction must be made between the bonding form of the element: inorganic phosphorus has the highest availability for the animal and occurs in mineral sources such as monocalcium phosphate. Organic non-phytin phosphorus has medium availability. It is found in vegetative plant parts and e.g. in milk. Phytin phosphorus has the lowest availability for monogastric animals and poultry. It is the main form of binding in cereals, legumes and oilseeds. By using the enzyme "phytase", the digestibility of phytin phosphorus can be significantly increased in monogastric animals such as pigs and in poultry.
Supplementing feed with mineral phosphorus is primarily done via mono- and dicalcium phosphate.