Vitamins- Vitamins- organic compounds that are required in minimal quantities to support thenormal metabolism of the body- General function o Nurture/ support (allow for proper metabolism) help to maintain life Growth  Reproduction  Maintenanceo Prevent deficiency diseaseso Help enzymes release energy from carbohydrates, lipids and proteins  They do not provide energy - Classification o Fat soluble  Vitamin A  Vitamin D Vitamin E- primary function as a cell membrane bound antioxidant Vitamin K – primary function is to support blood clotting o Water Soluble  B-complex- Thiamin (B1)- Riboflavin(B2)- Niacin (B3) o Nicotinamide o Nicotinic acid- Pantothenic acid (B5)- Pyridoxine (B6)- Cyanocobalamin (B12)- Biotin - Folacin (Folic acid)  Vitamin C P-aminobenzoic acid- PABA Myoinositol - Inositol - Fat soluble vitamins o Digestion & Absorption  Occurs in the small intestine - Duodenum/jejunum o Fat digestion o Micelle/brush border- GI epithelium o Chylomicron-lymphatic system (except in a bird)ooo Vitamin A Sources- High (100-760 U/g)o Liver o Liver oil o Carrots o Spinacho Bermuda grass (late vegetative) - Medium (10-100 U/g) o Butter. Margarineo Cheese o Broccolio Alfalfa (late vegetative) - Low (1-10 U/g)o Milko Grapeso Bananas o Appleso Zucchinio Peaso Distillers grains Factors affecting digestion and availability - Status of diet - Presence of oxidizing factors- Environmental conditions - Plant dry matter content- Forage type - Plant species- Ruminal disappearance (40-70%) Three forms- Retinol - Retinal - Retinoic acid Configuration - All trans-100% active- Trans/cis- All cis Not found in plants  Derived from carotenes Carotenes- Beta caroteneo Examples- alpha & gamma carotene, beta zeacarotene, cryptoxanthin Storage/ Transport/ Elimination - Transport o Chylomicron to livero Liver to tissues RBP (retinol binding protein + albumin) Albumin - Storage o 90% in liver  toxicity may be an issue- Eliminated via bile - Less efficient at absorbing carotenes = white fat o White fat dog, pig, goat, sheep, rabbito Yellow fat human, cattle, horse Function - Vision- Reproduction - Epithelial differentiation/maintenance (connected to reproduction and immune response) - Bone growth  Deficiency/ Toxicity - Kuppfer cell- resident macrophage in the livero Vitamin D Sources- Sunlight- Sun cured forage- Grain- provitamin - Vegetables- provitamin- Fortified milk- Egg yolk- Bone meal- Fish liver- Microorganisms- D3 - Derived from 7-dehydrocholesterolo Animal sterol- precursor cholesterolo UV light converts 7-dehydrocholesterol to cholecalciferol - Exclusively produced in animal products - Function- Precursor to formation of calcitrol (steroid hormone) Calcitrol primary function - Calcium- Phosphorus homeostatsiso Targetso Gastrointestinal absorptiono Kidney reabsorption (Ca++)/elimination (PO4-)o Bone formation o We are trying to increase blood calcium levels- Parathyroid hormone increases D# and Ca++ (causes bone reabsorption- Calcitonin antagonizes PTH effects D2 - Derived from ergosterolo Plant sterolo UV light activates ergosterol to ergocalciferol - All sterols possessing Vitamin D activity contain the same steroid nucleus- Usual dietary source of vitamin D. - Very similar to D3 but there is a double that changes - Plant form  Storage/ Transport- We don’t store a lot of VD - Storageo Aquatic species- significant storage in livero Land animals/humans Little storage Blood and liver (primary)  Lungs, kidney  Persistence of VD during shortage- decreased rate of turnover- Transporto Transport through transcalciferin (pretty much all forms are transported through this)  Ligands- vitamin D- 25-hydroxy vitamin D3- 24,25-dihydroxy vit. D3- 1,25-dihydroxy vit. D3- active hormone – calcitrol a-globulin albumin Rickets- Osteomalcia is counterpart in adults- Symptoms/Physiological Effectso Decreased calcium and phosphorus in bone matrix Weak bones (curving and bending apparent) Enlarged hock and knee joints Beaded ribs Deformed thoraxo Inhibition of growth- effects overall growth in an animalo Anorexia and weight losso Cartilage maturation fails Toxicity o Hypercalcemia and hypercalcuriao Tissue necrosiso Calcification of soft tissue and demineralization of boneo Anorexiao Stiffness and lameness o Muscular weaknesso Disorientation - Very hard to actually get- Decreased kidney secretion of calcium- Decreased urine excretion of calcium - Water soluble vitamins o Classificationo General information  Absorbed across the small intestine  Absorption often highly regulated by other vitamins or binding proteins in the small intestine in blood  Transported away from small intestine in blood Typically not stored; instead, kidney filters excess into urine- With the exception of Vitamin B12- Used and then excess is sent out through waste (urine)  Ruminants- Water soluble vitamin requirement met almost entirely from microbial synthesis in the rumen and lower GI tract. o Thiamin (B1) Coenzyme- Decarboxylation reactionso Glucose metabolism Very important in this Conversion pyruvate to Acetyl CoA  this is a loss of one oxidized carbonso TCA cycle Conversion a-ketoglutarate to succinyl-CoA  Gycolysis- This is what is loss - These vitamins are aiding our ability to metabolize carbohydrates into useable energy  Deficiency- Blood pyruvic acid (pyruvate) and lactic acid concentrations in creaseo Pyruvate decarboxylation does not occur- Carbohydrate and lipid metabolism are seriously disturbedo Result of the disturbance in the TCA cycle- Reduction in appetite (Anorexia)- the chemistry in the body is telling the brain that the body doesn’t need to eat much less want to eat.