Vitamins are divided into fat soluble and water soluble groups. Fat soluble vitamins include A, D, E and K. Water soluble vitamins include the B complex vitamins and vitamin C. Vitamins serve essential roles like visual processes, immune function, bone health and acting as antioxidants. They are obtained through the diet or synthesized in the body and deficiencies can cause diseases like rickets, scurvy or neurological issues depending on the vitamin. Requirements vary based on species, life stage, environment and health status.

1. Vitamins

2. General Concepts
• Divided into two major groups: fat soluble and
water soluble (B series, C, Folic acid e.t.c)
• fat soluble: A, D, E, K
• most of the 15 shown as essential for man
• requirements vary with species, size, growth rate,
environment (temperature, presence of toxins,
etc.) and metabolic function (growth, stress
response, disease resistance)

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7. Vitamin A
• Vitamin A is a thermally stable in oxygen-free
environment and can withstand the heat of
60, 100 do 120°C. But, at the air at higher
temperatures (about 60°C) it decomposes
rapidly, especially under acidic conditions.
Sunlight also promotes vitamin A
decomposition.

8. Structures of Vit A analogues

9. Characteristics
• The compounds are polyenes. -
polyunsaturated organic compounds that
contain alternating double and single bonds.
• Vitamin A functions include the visual process,
immune function, gene transcription, and skin
health.
• Retinol, retinal, and retinoic acid are members
of the Vitamin A group. Provitamin A
carotenoids are also members of this group. β-
carotene, the orange pigment found in carrots

10. .• β-carotene is responsible for the orange
colouration of many different fruits and
vegetables. E.g. mangoes, carrots, cantaloupes,
apricots
• β-carotene is generally absorbed by passive
diffusion in the body. The compound is cleaved
symmetrically at a central carbon-carbon double
bond. This reaction requires molecular oxygen
and is catalysed by the enzyme β-carotene 15,15
β-monooxygenase to give two retinal molecules.
• Retinoids is the term used to describe a class of
compounds that are related to Vitamin A.

11. Vitamin D3: cholecalciferol

12. .• Cholecalciferol (Vitamin D3) andergocalciferol (Vitamin D2)
• Vitamin D is colloquially referred to as the ‘sunshine
vitamin’.
• Humans are also able to biosynthesise cholecalciferol
through the photolysis of 7-dehydrocholesterol by UV light
in the skin.
• Cholecalciferol is hydroxylated in the liver to form calcidiol
and then in the kidneys, to calcitriol. As the name suggests,
calcitriol has three hydroxyl groups.
• Calcitriol is the hormonally active form of the vitamin.
• This compound interacts with the vitamin D receptor (VDR)
which is a nuclear receptor.
• This ligand-receptor complex acts as a transcription factor.
Calcitriol is involved in the regulation of the levels of Ca2+
and PO3- ions in the bloodstream.
• This hormone also induces the synthesis of proteins that
are involved in calcification and bone remodelling.

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• Sources: Fish liver oil, cow's milk, butter, egg yolk
• Hypovitaminosis D is a deficiency of vitamin D
often resulting from low vitamin D in the diet
inadequate exposure to sunlight, impaired ability
to absorb vitamin D because of a certain disorder,
or combinations thereof. Vitamin D deficiency
results in poor mineralisation of the bone and as
a consequence, bone-softening diseases such as
osteomalacia in adults and rickets in children.
• Both cholecalciferol and ergocalciferol are used to
treat known or suspected vitamin D deficiency. In
some cases, calcitriol is used instead.
• Interestingly, hypervitaminosis D does not appear
to arise from excessive exposure to sunlight.

14. Vitamin E

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• The Vitamin E group consists of eight vitamers. These
are the α-, β-, γ-, and δ- tocopherols and tocotrienols.
• Germ oils of cereals are good sources of the vitamin.
• These fat-soluble compounds serve primarily as
antioxidants. Due to their ability to dissolve in fats,
they are often incorporated into cell membranes.
• These compounds serve as scavengers of reactive
oxygen species which protect cell membranes from
oxidative damage.
• α-tocopherol protects cellular lipids by reacting with
radicals, forming α-tocoquinone.
• Deficiencies are also known thought to lead to
neurological dysfunction.

16. Vitamin K: menadione
• Phylloquinone (Vitamin K1) and menaquinones
(vitamin K2) are natural Vitamin K vitamers.
• Vitamin K is involved in the post-translational
modifications of proteins involved in blood
coagulation.
• The post-translational modifications of these proteins
allow the binding of calcium ions.
• Vitamin K deficiencies cause bleeding problems.
Vegetables such as kale, broccoli, and spinach are good
sources of Vitamin K1. Intestinal flora, particularly
gram-positive bacteria are known sources of vitamin K.

18. Riboflavin: B2
• Function: metabolic degradation of proteins,
COH, lipids
• sources: plants, bacteria, yeast, fish solubles
• deficiency: cataracts (fish), vision, crooked limbs
• requirements: 9 mg/kg (channel catfish), 5
mg/kg (tilapia)
• requirements: 50 mg/kg (shrimp)

19. Niacin
• Function: transport of hydrogen ions as NADP,
NADPH; electron transport, fatty acid, cholestrol
synthesis
• forms: niacin, nicotinic acid, nicotinamide
• sources: rice polishings, yeast, rice bran
• deficiencies: pelagra, dermatitis, anemia (fish),
skin lesions (fish), sunburning (fish)
• Can fish convert tryptophan to niacin?
• requirements: 14-28 mg/kg (carp, catfish)
• requirements: 400 mg/kg (shrimp)

20. Folic Acid
• Recently shown as very important for
pregnant females to avoid birth defects
• function: synthesis of purines, pyrimidines,
nucleic acids
• sources: yeast, alfalfa meal, full-fat
soybeans
• deficiencies: anemia, large erythrocytes,
pale gills (fish)
• requirements: 1-4 mg/kg (fish, shrimp)

21. Cyanocobalmine
• Last of 15 vitamins to be identified
• chemically complex, cobalt nucleus
• function: coenzyme in metabolic reactions,
maturation of erythrocytes, uracil->thymine
• deficiency: pernicious anemia, nerve
disorders
• requirement: very low 0.015 mg/kg or not
at all

22. Ascorbic Acid: C
• Both finfish/shellfish very sensitive to this
vitamin, especially as juveniles
• function: antioxidant, stress reducer, bone
calcification, iron metab, tyrosine metab, blood
clotting
• deficiency: scoliosis (lateral), lordosis (vertical),
fin erosion, black death (shrimp)
• toxicity: toxic at over 150-200 mg/kg (shrimp)
• sources: synthesized from glucose, usually added
as chemical form
• requirement: 100 mg/kg varies w/age,
metabolism