Role of Calcium and Phosphorous in Animal Nutrition

Role of Calcium and Phosphorous in Animal Nutrition

Maskare Rahul Mahavirprasad¹, Monika Karnani², Sheela Choudhary³ and Manju⁴

Department of Animal Nutrition

Post Graduate Institute of Veterinary Education and Research (PGIVER)

NH-11, Agra Road, Jamdoli, Jaipur

¹MVSc Scholar, Department of Animal Nutrition, PGIVER, Jaipur

²Assistant Professor, Department of Animal Nutrition, PGIVER, Jaipur

³Professor and Head, Department of Animal Nutrition, PGIVER, Jaipur

⁴Assistant Professor, Department of Animal Nutrition, PGIVER, Jaipur

 Minerals are the nutrients that animal body needs in order to grow and function appropriately. There are two main mineral groups. Macro minerals are required in amounts of 100 milligrams or more per day. eg: calcium, phosphorus (phosphates), magnesium, sulfur, sodium, chloride, and potassium. Micro minerals are often referred to as trace minerals, meaning they are present at low levels in the body or required in smaller amounts in the animal diet. eg: chromium, cobalt, copper, fluorine, iodine, iron, manganese, molybdenum, selenium and zinc.

Calcium (Ca) and Phosphorus (P) in Bone

Ca and P make up more than 70% of the body’s ash. Bone and teeth contain around 99% of the Ca and 80% of the P in the body. Ca and P are commonly found in a 2:1 ratio in bone. Ca and P are stored in the bone. A typical adult has 45% water, 20% protein, and 10% fat. On a fat-free and moisture-free basis, bone contains 36% calcium, 17% phosphorus, and 0.8% magnesium.

Calcium (Ca) and Phosphorus (P) in Blood

Calcium is completely absent from blood cells. Plasma Ca exists in two forms: soluble ionized form (60% of total) and protein-bound form (mainly albumin and plasma protein). Ca levels in the blood affect hormone secretion, which in turn regulates calcium deposition and release from bone. Low levels enhance parathormone secretion, which promotes calcium and phosphorus release from bone. Ca is used to meet the animal’s Ca requirements, whereas P is expelled.

Whole blood contains 35 to 45 mg P/100 ml, with the majority of it in the cell. The element can be found in a variety of forms, the most common of which is organic combination. Inorganic phosphorous is present in plasma (4-9 mg/100ml). It is clear that phosphate is constantly exchanged between organic and inorganic forms. The amount is higher at birth than at maturity, with the greatest drop occurring early in life. The phosphorus level in the blood is more easily altered by diet than the calcium.

 Calcium (Ca) and Phosphorus (P) in Tissue

Outside of the bone, just 1% of the body’s calcium is broadly dispersed throughout the organ and tissue. Large amount of phosphorous are present mostly in organic combination such as phosphoprotein, nucleoprotein, phospholipids, phosphocreatine and hexose phosphate. P accounts for 0.15 to 0.2% of the body’s soft tissue.

 Function of Calcium

• Bone and Tooth formation: Calcium is a key component of bone and tooth formation. It gives the skeletal system strength and structure, contributing to overall body stability and support. It is required for the growth and development of bones and teeth, particularly during the adolescent and adult stage.
• Receives a signal to contract, calcium is released from storage sites within the muscle cells, allowing the muscle fibers to slide past each other and generate movement. This process is crucial for various physiological activities, such as locomotion, digestion, and cardiac function.
• Nerve Function: Calcium is essential for nerve transmission. It helps to release neurotransmitters, which are chemical messengers that allow nerve cells to communicate with one another. Calcium ions promote the fusion of synaptic vesicles holding neurotransmitters with the nerve cell membrane, allowing signals to be transmitted between neurons.
• Blood Clotting: Calcium is required for blood clotting. When a blood vessel is injured, platelets clump together to form a clot and avoid excessive bleeding. Calcium ions are essential for the activation of numerous clotting factors in the blood, which starts the clotting cascade and allows for the development of a stable blood clot.
• Enzyme Activation: Calcium helps to activate various enzymes, which are proteins that catalyze biochemical reactions in the body. It aids in the regulation of enzyme activity, allowing them to carry out their specific function. Calcium is required for the proper activity of several enzyme activities, including those involved in muscle contraction, nerve signaling, and hormone production.
• Hormone Secretion: Calcium is required for the secretion of several hormones in the body, including insulin, which regulates blood sugar levels, and parathyroid hormone (PTH), which aids in the maintenance of calcium homeostasis. Calcium ions are involved in the signaling pathways that cause endocrine glands to release hormones.
• It’s important to note that maintaining an appropriate level of calcium in the body is crucial. Calcium homeostasis is tightly regulated by various hormones, including PTH, calcitonin, and vitamin D, to ensure the proper functioning of these physiological processes.

Function of Phosphorous

• Phosphorus is an essential component of adenosine triphosphate (ATP), the principal chemical used by cells to store and transfer energy. When ATP’s phosphate bonds are broken, it releases energy, which is used for a variety of cellular operations such as muscular contraction, nerve impulse transmission, and chemical synthesis.
• DNA and RNA Formation: Phosphorus is required for the construction of DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), the genetic components of living creatures. Phosphate groups are essential components of the nucleotide molecules that constitute the backbone of these molecules, giving stability and allowing genetic information to be transmitted.
• Cell Membrane Structure: The primary elements of cell membranes are phospholipids. These molecules are made up of two hydrophobic (water-repelling) fatty acid tails and a hydrophilic (water-loving) head. The hydrophilic heads have phosphate groups that attract water, while the hydrophobic tails face inward, forming a barrier between the inside and exterior of the cell.
• Bone and Tooth Mineralization: Phosphorus, in the form of calcium phosphate, is essential for bone and tooth mineralization. It contributes to healthy bones and teeth by providing structural support and strength to the skeletal system.
• Enzyme Activity and Metabolic Processes: Phosphorus participates in a number of enzymatic reactions and metabolic processes in the body. It functions as a co-factor or as a regulator of several enzymes, regulating the speed and efficiency of biochemical reactions.
• pH Buffering: Phosphates can act as buffers, assisting in the maintenance of cell and body fluid pH balance. By absorbing or donating protons (H+ ions), they can withstand dramatic variations in acidity or alkalinity.
• Phosphorylation, the addition of phosphate groups to proteins, is a common method for cellular signaling and regulation. Proteins can be activated or deactivated by adding or removing phosphate groups, affecting their activity and cellular response.

Absorption and Excretion of Calcium and Phosphorous

• The small intestine absorbs Ca. Ca is carried in the blood in two forms: ionized and protein bound. The solubility at the moment of contact with the absorbent membranes determines absorption.
• Vitamin D is required for the synthesis of a protein required for Ca transport in the intestinal mucosa (Ca binding protein- cadmolin and osteopontin).
• High quantities of inorganic phosphorous, phytin phosphorous, and Mg in the diet interfere with Ca absorption.
• Lactose, a slowly digested sugar, improves Ca absorption. Ca absorption is reduced by oxalate and phytates.
• Ca homeostasis appears to be influenced by dietary Ca and P levels, vitamin D, parathyroid hormone (PTH), and calcitonin levels.
• High Ca levels in the diet reduce absorption efficiency.
• An excess of either Ca or P inhibits the absorption of the other. The Ca/P ratio is critical. Non-ruminant ratios are more important than ruminant ratios.
• The small intestine releases phosphate, which is then absorbed. At the moment of contact with the intestinal mucosa, the phosphate must be in solution. Therefore, the absorption of the phosphate ion will be reduced by any substance or cation that forms an insoluble complex with it.
• The apparent digestibility of ash cannot be determined, thus this is useless. The explanation is that both minerals that have been absorbed and metabolized by the body and so served it, as well as those that have eluded absorption, are excreted through the defecation.
• Faeces are the main route for Ca excretion in all species. Herbivores excrete phosphorus mostly through their faeces, whereas carnivores excrete it primarily through their urine.

 Effect of High Intake of Calcium

• When dietary calcium consumption is high and not accompanied by an increase in zinc, swine develop serve parakeratosis. The effects of Mg shortage are increased by high levels of Ca and P in the rations of swine and poultry. Kidney stones are said to arise as a result of high Ca intake. Chronic consumption of excessive dietary Ca levels may also result in an overproduction of calcitonin and aberrant bone formations such osteopetrosis (dense bone).
• Due to its superb homeostatic mechanism, it is not typically thought of as a harmful element. Fast-growing strains were more susceptible to hypercalcemia and growth retardation when the feeding Ca content of chicks was doubled to 2.05g/kg DM (Hurwitz et al., 1995). Excessive Ca in the diet impairs the absorption of other nutrients, which makes P and Zn deficiency easily induced in non-ruminants. Hypercalcemia can result in tissue calcification that is life-threatening, however it typically happens as a side effect of P insufficiency or excessive vitamin D3 and its analogue exposure.

Effect of Deficiency of Calcium

• Milk Fever (Parturient Paresis): It is a calcium deficient condition that commonly appears in dairy cattle around the time of calving. The abrupt increase in calcium demand during milk production can overwhelm the cow’s ability to mobilize calcium from reserves, resulting in low blood calcium levels. Affected cows may show signs of weakness, loss of appetite, decreased milk supply, and trouble standing.
• Rickets: It is a disease that typically affects young animals, such as puppies, kittens, and young agricultural animals. It is characterized by insufficient mineralization and bone growth as a result of calcium and vitamin D deficits. Rickets can cause skeletal abnormalities, weak or fragile bones, delayed growth, and muscle weakness in animals.
• Osteomalacia: Similar to rickets, osteomalacia primarily affects adult animals. It is caused by a deficiency of calcium and vitamin D in the diet, as well as reduced absorption of these minerals. It causes softening and weakening of the bones, making them brittle. It can cause pain, lameness, decreased mobility, and muscle weakening in animals.
• Osteoporosis: This disease causes bones to become weaker and thinner, which increases the risk of fractures. It happens when the rate of bone resorption (breakdown) outpaces the rate of bone synthesis, resulting in a loss of bone mass and density.
• Osteopenia: It is a condition characterized by low bone mineral density, which makes bones fragile and more prone to fractures.
• Egg-Binding: Calcium shortage in birds, especially in laying hens, can result in egg-binding. Lack of calcium in the diet might make it difficult for hens to build sturdy eggshells. Eggs may end up getting caught in the reproductive system as a result, which can cause problems and even endanger life. Birds who are impacted could exhibit signs of distress, stomach swelling, and challenges laying eggs.

Effect of High Intake of Phosphorous

• Nutritional Secondary Hyperparathyroidism: It is caused by an excess of P and a deficiency of Ca. P overflow reduces Ca absorption. The parathyroid is prompted by the ensuing hypocalcemia to release parathormone, which mobilized calcium from bone to raise the blood level. A higher bone turnover rate is also brought on by a high dietary P intake. Fibrous connective tissue invades the region in horses and monkeys, leading to larger facial bones. As a result, the condition is also known as big head disease or osteodystrophy fibrosa or miller’s disease or bran disease.

Effect of Deficiency of Phosphorous

• Pica: It is distinguished by a P deficit. Loss of appetite, even depravity, manifested in the consumption of bones, wood, clothing, and other items (dirt, plastic, etc.) to which the animal may have access. The animal became severely malnourished. Allotriophagia (a generalized term), osteophagia (craving for bone), and Sacrophagia (craving for flesh) are all names for the depraved (pica). These forms of pica are expression of deficiency of not only P but also Na and K.
• Reproduction: Low dietary P intake has also been linked to low fertility; ovarian dysfunction resulting in inhibition, depression, and oestrus irregularity.
• Bone and tooth abnormalities can cause gait stiffness, swollen and painful joints, bone bending or deformation, back arching, and bone fracture.

 Source of Calcium and Phosphorous

 Supplements of Calcium and Phosphorous

(Source- D.V. Reddy, Principle of Animal Nutrition and Feed Technology)

 Calcium and Phosphorous Content of Some Common Feed

(source- Handbook of general animal nutrition, Udeybir Singh Chahal, P.S.Niranjan, Sanjay Kumar)

Average Content of Calcium and Phosphorous 

(source-Handbook of general animal nutrition, Udeybir Singh Chahal, P.S.Niranjan,     Sanjay Kumar)

ROLE OF MINERALS IN LIVESTOCK PRODUCTION

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