Dr. R. Selvakkumar, Dr. K. Chinnamani, Dr. A. Rajaduari & Dr. D. Anandha Prakash Singh

Department of Livestock Production Management
Veterinary College and Research Institute

A disease is a condition that deteriorates the normal functioning of the cells, tissues, and organs which will affect the normal physiology of the affected organism. The causative factor for disease may be from a number of sources and some of them were yet to be identified. But, whenever we hear the word “disease”, we always accuse microorganisms like bacteria and viruses as the culprit. But the tangible truth is, diseases may be caused both by the Infectious (Pathogenic micro organism) and Non-infectious factors ( genetics, malnutrition, environment). This fact is true in the case of poultry and they may also be affected by a wide range of diseases caused by non-infectious agents. In the non-infectious category, nutritional deficiency plays a major role in causing diseases of poultry. The nutritional deficiency always arises from the feed with compromising quality and can be easily rectified by providing the birds with the correct amount of nutritionally balanced diet.

Classification of nutrient essential for poultry

Based on the quantity needed, nutrients are broadly classified in to

  • Macronutrients (Fat, Protein, Carbohydrate etc…)
  • Micro nutrients (Vitamins, Minerals etc)

Vitamin deficiency diseases

The source of vitamins in the poultry feed is from its feed ingredients from which the feed was produced as well as from the Vitamin premix added with the feed. Since, the  strains used in the present poultry  industry is having a tremendous production capacity, they need an extra amount of vitamins as premix apart from the feed ingredient bound vitamins. The deficiency of water soluble vitamins expresses its effect faster than the fat soluble vitamins. Fat soluble vitamins have some reserve in the body and they are used for some time by the birds and the birds show the deficient symptoms only after the exhaustion of the bodily stored vitamins.

Vitamin A deficiency/ Nutritional Roup

Vitamin A plays a vital role for the normal  function of the immune system and also for epithelial integrity (The mucous membranes of GIT, respiratory, urogenital and epithelium lining of eyes and skin). The time taken for the expression of deficient symptoms were based on the liver store of Vitamin A.

The clinical manifestation of Vitamin A deficiency ranging from Xerophthalmia, impaired growth performance and increased susceptibility to many diseases. Production loss and diminished hatchability are the main sequelae of vitamin A deficiency.

Gross signs of this deficiency include anorexia, ruffled feathers, Comb and wattles becoming pale, poor growth, nasal and ocular discharge, drowsiness and thick exudate in eyes.

Etiological/ predisposing factors

Competition between intestinal microorganism and host for Vitamin A, stress, birds fed with the ration devoid of corn as an ingredient, chicks  hatched out from a layer having a low Vitamin A reserve, confinement of free range birds and chronic diseases of intestine and Liver

 Treatment and prevention

  • Supplementation of vitamins and cure the secondary bacterial infection immediately
  • Feeding a ration with adequate vitamin A
  • Avoid long storage of prepared feed.
  • Use of Antioxidants during feed preparation.
  • Feeding pet birds with leafy vegetables and fruits

 Vitamin D deficiency           

This vitamin is required for the normal absorption and metabolism of calcium and phosphorus. Rickets in young growing chickens or in osteoporosis and poor eggshell quality in laying hens are the more evident disorders of Vitamin D deficiency.

Lack of Vitamin D in poultry feed, use of sulphur drugs may interfere with Vitamin D utilization and catalyzation of Vitamin D by some minerals are few predisposing factors for the Vitamin deficiency in Poultry. 

Injection of Vitamin D followed by adding a sufficient amount of Vitamin D in the regular diet is the line of treatment for the affected birds. Adding a recommended level of Vitamin D in the feed with a proper Calcium and Phosphorus ratio in the feed will help to prevent the Vitamin D deficiency in poultry. 

Vitamin  E deficiency 

Vitamin E plays a role in normal reproduction, normal integrity of the CNS and muscular systems. Apart from this, it also acts as an antioxidant. Oxidation of fatty acids in the diet, improper feed preparation and mixing and low levels of Vitamin E in the feed are some predisposing factors for the deficiency of this  vitamin.  Deficiency of selenium will also result in a deficiency of vitamin E. Testicular degeneration in adult males, increased embryonic mortality are also the effect of Vitamin E deficiency.

Encephalomalacia, muscular dystrophy and exudative diathesis are the manifestations of Vitamin E deficiency and they are noticed independently or combined together.  Encephalomalacia is commonly known as crazy chick disease. The signs are associated with CNS which include ataxia, disequilibrium, falling on the back, frequent movements with the wings, clonic spasms, twisting of the head and torticollis. Exudative diathesis  is characterized by edema of subcutaneous tissues and poor growth, ruffled appearance and  swelling behind the crop are some of the symptoms.  

Early administration of Vitamin E will show better response  by the affected birds and is not possible in the advanced stage.

Vitamin K Deficiency

Vitamin K is essential for the production of prothrombin which is essential in blood clotting. So, a deficiency of vitamin K results in an increase in haemorrhaging.

Subcutaneous and internal haemorrhages are noticed in severe deficiency which is very life threatening. Deficiency causes increased embryonic mortality and the dead embryos having haemorrhagic spots. Deficiency of vitamin K in the diet and use of high levels of sulfaquinoxaline for treating coccidiosis in poultry causes Vitamin deficiency for poultry.

Thiamine deficiency (B1)

Thiamine pyrophosphate (TPP), the active form of thiamine, functions as a coenzyme in the production of energy from glucose or that convert glucose to fat for storage in the tissues. Hence, the deficiency of thiamine will result in disturbance of basic energy function. Thiamine is sometimes called an “anti-stress” vitamin due to its role in  strengthening the immune system and improving the body’s ability to withstand stressful conditions.

Vitamin B1 deficiency in poultry is characterized by extreme anorexia followed by loss of weight, ruffled feathers, leg weakness and unsteady gait. Paralysis of muscles of legs and wings are noticed.In severe cases affected birds sit on its flexed legs and draw back the head in a “star gazing” position.  Polyneuritis and death are the sequelae of this vitamin deficiency. Administration of Vitamin B1 will show a quick recovery among the affected birds

Riboflavin deficiency (B2)

Even though many tissues may be affected, epithelium and the myelin sheaths of some of the main nerves are major targets for Riboflavin deficiency.“curled-toe” paralysis is the manifestation of riboflavin deficiency by affecting the sciatic nerve.

Other symptoms are slow growth, ataxia, emaciation, low egg production and hatchability.

In sub clinical cases recovery is noticed after giving additional levels of Vitamin B2 but we can not expect recovery in long standing cases.

Nicotinic Acid (B3)

Since poultry birds can synthesize a small amount of this vitamin on their own, marked deficiency of niacin is not possible in chickens. Skin and digestive disorders are noticed in the deficient birds. Primary symptoms are loss of appetite, retarded growth, general weakness, and diarrhoea. Enlargement of the tibiotarsal joint was also noticed in the affected birds.

Pantothenic acid deficiency (B5)

Signs of Pantothenic aciddeficiency are related to general avian metabolism. The major lesions of pantothenic acid deficiency are noticed in the nervous system, adrenal cortex, and the skin. Reduced egg production, marked drop in hatchability, retarded growth, rough plumage, lesions around the mouth and embryonic mortality are the deficiency symptoms of this vitamin.

 Pyridoxine Deficiency (B6)

Vitamin B6 helps in make several neurotransmitters in the body, which are carry signals from one nerve cell to another. It is needed for normal brain development and function.

Pyridoxine also helps in the production of serotonin and norepinephrine, which influence mood, and melatonin, which helps in regulate the circadian rhythms. It is required by several enzymes, including those involved in the breakdown of amino acids. Hence, the deficiency  can result in reduced nitrogen retention. Vitamin B6 deficiency causes retarded growth, dermatitis, and anemia.

Folic Acid deficiency (B9)

Folic acid deficiency results in a macrocytic anaemia and leukopenia. Deficiency of this vitamin will affect the   epithelial linings, GI tract, epidermis, and bone marrow, as well as cell growth and tissue regeneration. Poor feathering, slow growth and anaemic appearance are the symptoms of folic acid deficiency. Paleness of comb, mucous membrane and mouth are some other symptoms.