Principle of Fish Nutrition

• Forms of Vitamin K:
• Phylloquinone ($K_1$): Natural plant form of vitamin K.
• Menaquinone ($K_2$): Bacterial synthesized form.
• Menadione ($K_3$): The synthetic, provitamin form of vitamin K, widely used as a stable water-soluble feed supplement (e.g., menadione sodium bisulfite, MSB) in fish feeds to support blood coagulation and prothrombin synthesis.
• Correct Option: Option 1 (Menadione).

• Vitamin C Biosynthetic Deficiency in Aquatic Animals:
• Finfishes and decapod crustaceans are incapable of endogenous biosynthesis of Vitamin C (L-Ascorbic Acid).
• Biochemical Basis: They lack the functional liver/kidney enzyme L-gulonolactone oxidase (GLO), which catalyzes the final terminal enzymatic step in the conversion of L-gulonolactone to L-ascorbic acid via the uronic acid pathway.
• Therefore, ascorbic acid is an obligate dietary micronutrient required to prevent scoliosis, lordosis, and impaired wound healing.
• Correct Option: Option 3 (Vitamin C).

• Ascorbic Acid as a Hydrogen/Electron Donor:
• Vitamin C (Ascorbic Acid): Acts as an essential biological water-soluble reducing agent and hydrogen/electron donor in metabolic hydroxylation reactions.
• Specifically, it reduces oxidized active-site iron ($Fe^{3+} \to Fe^{2+}$) in prolyl-4-hydroxylase and lysyl-hydroxylase enzymes, which hydroxylate proline and lysine residues during collagen biosynthesis.
• Correct Option: Option 2 (Vitamin C).

• Discovery and Nomenclature:
• The Polish biochemist Casimir Funk coined the term "vitamine" in 1912 (derived from vita = life + amine, as he believed the anti-beriberi factor, thiamine, was a vital amine).
• The terminal 'e' was later dropped when it was discovered that not all vitamins are organic amines.
• Aquaculture Context:
• John Halver: Widely celebrated as the "Father of Fish Nutrition", established the quantitative vitamin and amino acid requirements for salmonids.
• nalysis:
• (Casimir Funk): Correct.

Correct option: (3) Casimir Funk