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Phosphorus plays an important role in the nucleic acid synthesis, energy metabolism, muscle function, enzymatic activity, lipid metabolism, and bone mineralization. The concentration of phosphorus is found mostly (about 85%) in the bone as hydroxyapatite. About 10% of the total phosphorus in the body is made up of organic phosphates from nucleotides, phospholipids, and phosphoproteins.
Serum phosphorus (5%) is found in the form of the following (inorganic) phosphate ions: HPO4– and H2PO4-. The determination of serum phosphorus encompasses all forms in which it is found. It varies with serum pH, as phosphate acts as a buffer system.
The functional role, nucleotide formation has a role in energy metabolism – through adenosine triphosphate (ATP) and in the storage and transmission of cellular genetic material, through the formation of nucleic acids – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Calcium also plays a role in intercellular signaling (eg cyclic adenosine monophosphate – cAMP is a second-order messenger that is formed by stimulating a receptor coupled with an alpha-G-protein subunit that activates adenylate cyclase that converts ATP to cAMP. phosphorylation or dephosphorylation of some enzymes takes place during their activation, respectively their inactivation.
Bone formation is dependent on dietary phosphorus concentrations. Low phosphorus diets have been shown to limit the growth of birds, while high phosphorus intake has adversely affected calcium (Ca) metabolism and bone properties. Phosphorus concentrations in serum and bone may reflect changes in phosphorus homeostasis, and the content within a normal range is important for normal physiological function and optimal bone mineralization.
Calcium Depending on age, calcium stored in the bone can reach up to 98-99% of the total calcium in the body. It is stored in two forms: one that is easily mobilized – quickly used by the action of parathyroid hormone in case of a decrease in calcium in the blood; another difficult to mobilize, stored at the level of the bone compact from the surface of the bone.
Functional role of calcium, intercellular communication, being a second-order messenger, cellular excitability. Through the different distribution of ions (Na +, K +, Ca2 +) between the inside and the outside of the cell, at the level of the cell membrane a resting membrane potential is realized, and the transmission of the nerve impulse at the level of the synapses and the muscular contraction. Calcium plays a role in the release of acetylcholine (chemical mediator) in the synaptic cleft through calcium-dependent exocytosis. It depolarizes the muscle cell membrane and creates a potential for action at this level.
Cereals are a major component of the pigeon diet and have high concentrations of phosphorus, most of which are considered biologically unavailable. However, it should be noted that the ingredients for food are plants, especially wheat, which may contain significant endogenous phytase activity. Phytases can also be produced by various bacteria. Some authors have suggested that phytate is hydrolyzed by phytases produced by microorganisms present in the small intestine.
In addition, inorganic phosphorus supplements are added to the diet to fully meet the requirements of the birds as recommended by the phosphorus. Incorporating inorganic phosphorus levels into practice could contribute to higher feed costs and environmental pollution.
Therefore, this study aimed to investigate the effects of phosphorus levels in the diet without altering calcium levels on the performance of breeding pigeons and the bone characteristics of youngsters from 7 to 21 days, to know the phosphorus requirements.