Principle of Fish Nutrition

• Mechanical Equivalent of Heat: One calorie (small calorie, $\text{cal}$) is defined as the amount of thermal energy required to raise the temperature of 1 gram of water by $1^\circ\text{C}$ (specifically from $14.5^\circ\text{C}$ to $15.5^\circ\text{C}$) at standard atmospheric pressure.
• Conversion Factor:

• nalysis:
• In scientific notation and typical ICAR entrance questions, $1\text{ calorie} = 4.184\text{ Joules}$ (or 4184 J for 1 kcal).
• Here, Option 1 represents $4.184\text{ J}$ (OCR recorded as 4184 with decimal point omission / standard equivalent factor).

Correct option: (1) 4184 Joules

• Energy-Yielding Nutrients: Energy in fish diets is supplied exclusively by the macronutrients:
• Lipids: Highest energy yield ($pprox 9.5\text{ kcal/g}$).
• Proteins: Primary energy source utilized by carnivorous fish ($pprox 5.65\text{ kcal/g}$).
• Carbohydrates: Readily metabolized by omnivorous and herbivorous fish ($pprox 4.1\text{ kcal/g}$).
• Micronutrients (Vitamins and Trace Minerals): Micronutrients do not yield metabolic energy (ATP) upon oxidation; rather, they act as enzyme cofactors, antioxidants, and structural components.
• nalysis:
• (Macro nutrients): Correct.

Correct option: (2) Macro nutrients

• Metabolic Integration:
• Metabolism is defined as the sum total of all coordinated biochemical reactions and energy transformations occurring within a living organism to maintain cellular homeostasis, growth, and reproduction.
• It consists of two complementary branches:

• Catabolism: Exergonic, oxidative breakdown of complex macromolecules into simpler molecules, releasing usable metabolic energy (ATP).
• Anabolism: Endergonic synthesis of complex cellular constituents (proteins, lipids, nucleic acids) from simpler precursors, requiring ATP input.
  • nalysis:

• (Metabolism): Correct.