ROLE OF VITAMINS & MINERALS IN IMMUNITY DEVELOPMENT IN ANIMALS

Pashu Sandesh, 14 June 2021

• Keshav Gaur ^1*    • Dr. Sheela Choudhary ²    • Dr. Monika Karnani ³    • Dr. Manju ³

 ¹M.V.Sc. Scholar, Animal Nutrition Division, RAJUVAS-PGIVER, Jaipur (Rajasthan)

² Professor and HOD, Animal Nutrition Division, RAJUVAS-PGIVER, Jaipur (Rajasthan)

³Assistant Professor, Animal Nutrition Division, RAJUVAS-PGIVER, Jaipur (Rajasthan)

                                       *keshavgaur2512@gmail.com

Introduction –

• Nutrition plays an important role in determining the immunity of the animal in its lifetime. Their role is crucial during the early and late stages of the animal’s life span. The relationship between nutrition and immunity are interlinked to each other that nutrient as a single or in a group affects immunity either directly or indirectly.
• Directly nutrients affect the immune system by-

1. Triggering the immune cell activation or
2. Altering immune cell interaction 

• Indirectly by changing the substrates of DNA synthesis, changing, the physiological integrity of the cell, altering energy metabolism, or by altering the signals or hormones.
• Specific micro-nutrients like vitamins and minerals play a vital role in the augmentation of immunity while deficiencies cause immune suppression. The deficiency of a single or group of vitamins and minerals has an influence on the immune system. Identification of specific nutritional deficiency and supplementation with the respective deficient nutrition is the key to alter the immune status and boosting the immunity of the animal. 
• Deficiencies of Cu, Se, vitamin E and Co in cattle reduce the ability of isolated neutrophils to kill yeast and/or bacteria. Cu deficiency reduces antibody production, but cell-mediated immunity (CMI) is generally not altered. Chromium (Cr) stimulates an immune response in stress condition. Co deficiency has been associated with reduced resistance to parasitic infections. Vitamin-A precursor i.e. β-carotene enhances both cell-mediated and humoral response.

Specific Nutrients and their Effect on Immunity –

• In non-ruminants, folic acid, vitamin B₆, vitamin B₁₂, vitamin C, vitamin A, vitamin E, iron, zinc, selenium, and copper affect one or more indexes of immunity. In ruminants, their capability to synthesize vitamins with the help of microbial population; had refrained scientist to study their effects. But few reported that cobalt, copper, selenium, chromium, vitamin E and A have regulated the immune system in ruminants. 
• Vitamins A, D and E have direct effects on the immune system by supporting the manufacture and function of cytokines- -the chemical signalling molecules of the immune response. For some vitamins and minerals, the amount required for optimal immune response is greater than the amount required for growth and reproduction.
• Minerals, including Zn, Fe, and Se, can have a significant impact on immunity, with Zn deficiency; producing profound effects on T cell-mediated immunity, Fe levels affect in the microbiota composition and resistance to bacterial infection, and Se having an effect on inflammation and T cell and Macrophages polarization via alterations in prostaglandin production.

1. Zinc (Zn) 

• Zn plays an important role in transcriptional control through its action as a Zn-finger motif. Zn plays a key role in both cell & antibody-mediated immune response against infection. Cells deficient in Zn have a reduced ability to proliferate. The immune response requires a rapid proliferation of cells (e.g., T- and B-lymphocytes) in response to specific antigens and, therefore, Zn deficiency prevents this aspect of immunity from developing. 

2. Copper (Cu) 

• Natural Cu deficiency increases the susceptibility of ruminant animals to disease. Cu is needed for the proper development and maintenance of the immune system including the formation of antibodies and white blood cells. Copper deficiency results in decreased humoral and cell-mediated immunity, as well as decreased nonspecific immunity. Dietary Cu affects phagocytic as well as specific immune function regulated by phagocytic cells such as macrophages and neutrophils. 
• Two Cu-dependent enzymes, ceruloplasmin and superoxide dismutase (SOD), exhibit anti-inflammatory activity and may play critical roles in the prevention of oxidative tissue damage resulting from infection and inflammation. Copper is involved in the antioxidant system via its involvement in the enzymes Cu–Zn superoxide dismutase (SOD). It has been assumed that SOD has a central role in the defence against oxidative stress. 

3. Chromium (Cr) 

• The addition of Cr to livestock diets improves immunity. Chromium increase blastogenesis in the lymphocytes. Chromium supplementation improves cell-mediated and humoral immune response as well as resistance to respiratory infection in stressed animals. Stress results in elevated blood concentration of cortisol (which is known to depress immune functions), so Cr supplementation is found to lower serum cortisol concentration.

4. Iron (Fe) 

• The most profound changes associated with low iron levels are the reduction of peripheral T-cells, impairment of phagocyte, natural killer activities, lymphocyte interleukin-2 production, decreased delayed-type hypersensitivity and thymus atrophy. Iron deficiency anaemia was found to have impaired neutrophil bactericidal activities and cell-mediated immune functions which were reversible with adequate iron therapy.

5. Manganese (Mn)

• Mn has an active role in immune functions; where it helps in detoxifying free oxygen radicals, which can cause tissue damage produced by immune cells in response to killing bacteria.

6. Cobalt and Vitamin-B₁₂ 

• In ruminants, Vitamin B₁₂ is produced from cobalt by microbes in the rumen. Limited research indicates that Co deficiency affects neutrophil function and resistance to parasitic infection. Neutrophils isolated from calves deficient in Co had reduced ability to kill C. albicans (MacPherson et al. 1987; Paterson & MacPherson, 1990). 
• Vit. B₁₂ play a central role in immune processes because it governs cell pision and growth. Without adequate B12, white blood cells (WBC) can't mature and multiply. Vit. B₁₂ decreased white blood cell response and shrinkage of the critical immune system organ, the thymus.

7. Selenium (Se) and Vitamin-E

• Feeding of Se reduces the incidence of diseases by enhancing neutrophil killing activity. Se deficiency increases neutrophil adherence and could affect the ability of neutrophils to attack and sequester pathogen. 
• Vitamin E prevented the peripartum reduction in neutrophil superoxide anion production and impaired IL-1 production by monocytes and increases lymphocyte proliferation. 
• Injection of Se either alone or in combination with vitamin E significantly improved the production of specific antibodies against E Coli and that the production of specific antibodies was greater after the administration of Se alone.

8. Vitamin A and β-carotene 

• The integrity of the epithelial lining of mucosal surfaces; particularly of gastrointestinal, respiratory and urinogenital tracts with its mucus covering constitutes the major limb of the innate immune responses and is essential to prevent microbial invasion.
• Vitamin A might direct lymphocyte development and maintenance of the mucous membranes, which help fight off challenges from pathogens. The antimicrobial enzyme lysozyme depends on vitamin A for its synthesis. Impaired development of primary lymphoid organs and impaired cellular proliferation have been demonstrated in vitamin A deficient chicks. These effects were attributed to the impairment of lymphoid cellular proliferation and differentiation of primary lymphoid organs. 
• β-Carotene is the major precursor of vitamin A that occurs naturally in feedstuffs. Research suggests that β-carotene may affect immune function, independent of its role as a source of vitamin A. β-Carotene, as such, can serve as an antioxidant, while vitamin A is not an important antioxidant. 

9. Vitamin C 

• As an antioxidant, Vitamin C is an excellent source of electrons; therefore, it can donate electrons to free radicals such as hydroxyl and superoxide radicals and quench their reactivity. Supplementation of vitamin C improves components of the immune system such as antimicrobial and natural killer (NK) cell activities, lymphocyte proliferation, chemotaxis and delayed-type hypersensitivity. 
• Vitamin C acts against the toxic, mutagenic and carcinogenic effects of environmental pollutants by stimulating liver detoxifying enzymes. Vitamin C contributes to maintaining the redox integrity of cells and thereby protects them against reactive oxygen species generated during the respiratory burst and in the inflammatory response.

10. Vitamin D

• Vitamin D influences the body’s immune system -

1. By modulating the innate & adaptive immune system
2. Influencing the production of Cathelicidin- An endogenous antimicrobial peptide.
3. By regulating the inflammatory cascade.

• Vitamin D is a particularly potent modulator of mucosal immune function, with deficiencies producing marked changes in barrier function, gut microbiota, antigen-presenting cells (APC), polarization and activation of T cells and Macrophages.

Conclusion -

• Vitamins and minerals (micronutrients) play an important role in regulating and shaping an immune response. Deficiencies generally result in inadequate or dysregulated cellular activity and cytokine expression, thereby affecting the immune response.
• The interactions between micronutrients (like vitamins & minerals); immunology, & disease resistance are extremely complex. There are many factors that could affect an animal’s response to micronutrients supplementation such as the duration & concentration of micronutrients supplementation, the physiological status of an animal (pregnant vs. open), the absence or presence of dietary antagonists, environmental factors, and the influence of stress on micronutrients metabolism.