ROLE OF MICRONUTRIENTS ON ANIMAL IMMUNITY DR.C.KATHIRVELAN, M.V.Sc, PhD Assistant professor Department of Animal Nutrition College of Veterinary Science S.K.Nagar, Gujarat State 385 506 INDIA Respiratory burst Neutrophil H20 Bacteria
GSHpx H202 Bacteria SOD NADPH OXIDASE NADPH 2O2 2O-2 2 eNADP+
Chew,1996 INTRODUCTION Nutrition interact with animal immune system (Pring and Ahmed,1993) Micronutrients (Minerals and Vitamins) Minerals Zn, Cu,Cr.Se,Mn, Fe,Co Vitamins like E,beta carotene and vitamin A,Vitamin C Stress condition The requirement of micronutrient for optimal immune response is greater than the amount required for growth and reproduction (Harmon,1994; Scaletti,1992)
Micronutrients Minerals Zinc Copper Chromium Selenium Vitamins (Antioxidants) Vitamin E Carotenoids (beta carotene ) and Vitamin A IMMUNITY Immunity refers to,reactions by an animal body to foreign substances such as microbes and various macro molecules ( Abbas et al.,1991)
Immune system A collection of cells and molecules that protect the body against infection, malignancy and damaged cells ( Abbas et al., 1991) IMMUNITY INNATE Physical and chemical barriers Phagocytes (Neutrophils & Macrophages) -Inflammatory process.
ACQUIRED Specific towards particular antigen and enhanced with repeated exposure ACQUIRED IMMUNNE RESPONSE HUMORAL Mediated by B lymphocytes. CELL MEDIATED
Mediated by T lymphocytes (Galyean et al.,1999) B lymphocytes Mature in bone marrow Antigen binding receptor in their membrane B cells Memory cells
Plasma cells (Chew,1996) T lymphocytes Mature in thymus gland Function to; Killing infected cells. Stimulate microbial and cytotoxic activity of immune effecter cells T cell membrane receptor. Membrane protein Major Histo Compatibility (MHC) molecule. Three types of subpopulation T helper cells (Th cells) T cyto toxic cells (Tc)
T suppressor cells (Ts) T helper cells Secrete growth factor cytokines. Having membrane glycoprotein CD4 (Chew, 1996) Cells of the immune system B cells T cells NK cells Monocytes/macrophages Neutrophils Eosinophils Basophils
(Chew,1996) Measures of immune response Humoral immune response Measured by estimating the antibody (Ig) produced - Zinc turbidity method (McEwan and Fisher,1970) Measures of immune response Cell mediated immune response Lymphocyte transformation test , i.e Blastogenesis In vitro assay measures mitosis of cultured lymphocytes in response to mitogenic chemicals ( E.g.Concanavalin A ) by counting radio activity [counts per minute (cpm)] incorporated in to newly synthesized DNA from radio labelled precursors.This is expressed as Stimulation Index (SI) (Larson,1979)
Mean cpm in culture with mitogen Mean cpm in culture without mitogen In in vivo, antigen instead of Con A Mitogen Agents capable of inducing cell division in a high percentage of T cells or B cells . Poly clonal activators. Characteristics ConcanavalinA (Con A)
Phytohemoagglutinin (PHA) Pokeweed Mitogen (PWM) Source Jack bean Kidney bean Poke weed Target cells
B cells T cells T cells and B cells Burton,1995 MINERALS Zinc Zinc is component of numerous enzymes Super oxide dismutase (SOD) RNA Polymerase
DNA polymerase Ribonulease Thymidine kinase Zinc.. Zinc influences host defence mechanisam via: Phagocytic activity Cell mediated immunity
Humoral immunity Phagocytic activity Zinc enhances phagocytic activity of macrophages and neutrophils (Babior, 1978) Phagocytic activity through respiratory burst ( McCord & Fridovich,1969 ; Chew, 1996) Increase release of vasoactive amines by basophils Zinc.. Cell mediated immunity; Enhances T cell mediated immunity Zinc is a cofactor for thymic hormone thymulin
Thymulin deficiency Impaired T lymphocyte proliferation Impaired T lymphocyte function Humoral immunity: Increases antibody production (Bach,1983) Copper.. Copper immune mechanism Phagocytic activity
Neutrophils Monocyte Humoral Response: Increases antibody production Ab production decreased in Cu deficient diet (Gengelbech and spears, 1998) COPPER Copper is component of Superoxide dismutase (SOD) Ceruloplasmin. Modulate inflammatory response by phagocytosis
Copper.. Cell mediated immunity Mainly through T-lymphocytes (Th,Tc) by cytokine production inhibit viral replication Interlukin production B cell maturation NK cell activity Chemo tactic attraction Tumour necrosis factor Act on tumor cell-kill it. CHROMIUM
Component of Glucose Tolerance Factor (GTF). * Potenciate the insulin activity (Cheng and Mowat,1999) * Facilitate interaction between insulin and insulin receptor in target tissue. * Reduces cortisol level in stress. Cont.. In stress Increased cortisol in blood Antagonist the insulin action
Prevents glucose uptake by insulin receptor Prevent entry of glucose to vital tissue Immune system under stress. (Orth,1992) VITAMINS Vitamins
Act as natural antioxidant Includes Beta carotene and vitamin A, Vitamin E, Vitamin C Protect tissue against damage caused by free radicals. Free radicals are, Generated in normal cellular metabolism React with enzymes, DNA and damage the tissue Common free radicals are super oxide, hydrogen
peroxide, hydroxyl radical, fatty acid radical Antioxidant system of mammalian cells Component location Nutrient involved function Superoxide dismutase
cytosol Cu,Zn,Mn An enzyme that converts super oxide to hydrogen peroxide Glutathione peroxidase cytosol Se An enzyme that converts
hydrogen peroxide to water Catalase cytosol Fe An enzyme that converts Hydrogen peroxide to water Alpha tocopherol membrane Vitamin E
Break fatty acid peroxidation chain reaction Carotene membrane Carotene Prevents initiation of fatty acid peroxidation chain reactions Smith et al.,1984 Role of antioxidant on immunity Miller and Slebodzinska, 1993
Vitamin E and Selenium Vitamin E Vit E reduces harmful lipid free radicals. Enhances phagocytic activity of neutrophils, macrophages and NK cells. (Miller,1993) It is major antioxidant in the blood. Selenium Biochemical role through glutathione peroxide Enhance neutrophil function Cont Vitamin E and Selenium
Both vitamin E and Se influences the function of immune cells especially in mammary gland immunity Cows are immuno suppressed when plasma concentration of vitamin E and Se is low (Grasso et al., 1990) Milk and plasma levels of vitamin E in healthy and mastitis cows Milk Plasma 5
0.5 4 0.4 3 m g/L mg/L 0.6
0.3 2 1 0.2 0 0.1 Healthy 0 Healthy
n=75 Mastitis Mastitis n=75 Aroshi etal, 1986 Supplementation of Vit E (1500 IU) and Se (0.3ppm) increases plasma concentration of vitamin E and reduce incidence of mastitis (Smith,1986) Plasma concentration alpha tocoferol
Feeding heifers with supplemented vitamin E (1500 IU/d) and giving a selenium inj (0.3 ppm) 21 days post calving reduced several measures of mastitis.(Smith etal, 1984) IMI duration IMI at calving Clinical Mastitis High SCC cow s 0 20
40 % re duction 60 80 Beta carotene Act as an antioxidant Beta carotene: Enhances phagocytic activity of neutrophils- myloperoxidase enzyme Enhances phagocytic activity of macrophages peroxidase.
Increases lymphocyte toxicity CONCLUSION Zinc and copper enhances cell & humoral mediated immunity Chromium stimulate immune response in stress conditions Vitamin E and Se stimulate immunity against intra mammary infection Beta carotene enhances both cell mediated and humoral response
