ANSC 102 - Principles of Animal Nutrition (Vocabulary Flashcards)

What is Nutrition?

• Nutrition is the science of transformation of nutrients into body tissues and energy to support life and bodily functions.

• Key terms on the slides:

  • Nutrition, nutrients, diet, body tissues, nutrients sources, and their roles in farm animals.

• Core idea: Nutrients are classified by function and source; energy is not itself a nutrient, but a primary driver of feed intake and metabolism.

General Classification, Functions, and Sources of Nutrients

• Nutrients are defined as any feed constituent or group of constituents that aid in the support of life.

• Major nutrient classes: Water, Carbohydrates, Proteins, Lipids, Vitamins, Minerals.

• Important note: Energy is not a nutrient.

Water

• Major functions:

  • Nutrient digestion assistance

  • Nutrient transport

  • Chemical reactions and solvent properties

  • Waste excretion

  • Temperature regulation

• Sources:

  • Drinking water

  • Feed component

  • Metabolic water

Proteins

• Composed of amino acids (AAs).

• There are 20 amino acids that make up animal proteins.

• Digestively essential detail:

  • 10 AA can be formed in animal tissues; the others must be provided in the diet.lĺ

• Rumen microbes can synthesize some AA.Ĺĺĺl

• Llĺllĺlĺĺp in proteins:

  • In general, 100 g of protein contains about 16 g of nitrogen.

  • This corresponds to a nitrogen mass fraction of rac{16}{100} = 0.16, i.e., 16\% N by mass in protein.

Carbohydrates

• Products of photosynthesis in plants.

• Basic unit of carbohydrate structure is a simple sugar (glucose).

• Main CHOs in feeds:

  • Starch – readily digested CHO stored in plant seeds.

  • Cellulose and Hemicelluloses – major components of plant fiber.

Lipids

• Lipids are substances in plant and animal tissues soluble in organic solvents.

• Fats & Oils are important lipids in animal nutrition.

• Structure: typically glycerol backbone with 3 fatty acids (triglycerides).

• Fatty acids:

  • Saturated

  • Unsaturated

• General pattern: Fats generally have a higher proportion of saturated fatty acids (FAs) than oils.

Minerals

• Macrominerals (mostly required in larger amounts): Mg, P, Ca, Cl, Na, K, S.

  • Components of tissue structure.

• Trace elements / microminerals: Mn, Zn, Fe, Cu, Mo, Se, I, Co, Cr.

  • Actives or cofactors of enzymes.

Vitamins

• Organic nutrients required in small quantities.

• Essential for normal metabolism.

• Deficiency symptoms develop when absent or deficient.

• Generally, dietary essentials are required for all vitamins (except certain exceptions discussed below).

Vitamin Exceptions and Properties

• Niacin: can be synthesized in some animals from tryptophan.

• Vitamin C: can be synthesized in most animals.

• Vitamin D: can be synthesized in animals exposed to sunlight.

• Fat-soluble vitamins:

  • Stored in fatty tissues.

  • Poorly excreted.

• Water-soluble vitamins:

  • Readily excreted in urine.

  • Poorly stored in body (except B12).

  • Vitamin B12 is efficiently stored by the liver.

General Functions of Feed Nutrients

• 3 basic functions:

  • Structural material for building and maintaining body structure.

  • Source of energy for heat production, work, and/or fat deposition.

  • Regulators: for physiological processes or formation of body-produced regulators.

Nutrient Requirements (Overview)

• Energy requirement is a major nutritional need.

• At least 80\% of total feed intake should come from sources of calories.

• Animals eat to satisfy their energy requirements; energy need helps regulate feed intake.

Protein and Amino Acid Requirements

• Protein/AA requirements vary with:

  • Animal species

  • Stage of growth

  • Type of production

• Typical livestock diet composition:

  • 10-20\% protein/AA sources

  • 80-90\% energy-yielding nutrients

  • 3-5\% minerals

  • <1\% vitamin supplements

• Specific notes for pigs and poultry:

  • There is no carbohydrate requirement.

• Nutrient emphasis shown in a summarized intake layout: Water, Energy, Amino Acids, Fatty Acids, Vitamins, Minerals.

Nutrient Sources

• Roughages: > 18\% crude fiber; generally low energy.

• Concentrates: relatively high in digestible nutrients and low in fiber (<18\%).

• Concentrates include:

  • Energy feeds: cereal grains, milling by-products, fats and oils, tubers/root crops.

  • Protein feeds: animal protein feeds, plant protein feeds.

  • Feed supplements: amino acids, vitamins, minerals.

Classification of Animals Based on Type of Digestive System

• Non-ruminants or Monogastrics

  • Simple-stomached animals (e.g., Swine)

  • Modified simple-stomached animals (e.g., Poultry species)

  • Herbivorous monogastrics (e.g., Horse, Rabbit)

• Ruminants or Compound-stomached animals

  • Examples: Cattle, Carabao, Sheep, Goat

Digestive System Anatomy (General comparisons)

• Non-ruminants (Simple Stomach / Monogastric):

  • Esophagus → Stomach → Duodenum → Jejunum → Ileum → Large intestine → Cecum → Rectum → Anus

  • Some slides label Esophagus, Crop, Proventriculus, Gizzard for birds.

• Modified Simple Stomach (Birds):

  • Esophagus → Crop → Proventriculus → Gizzard → Duodenum → Jejunum → Ileum → Large intestine → Cecum (functional) → Rectum → Anus

• Herbivorous Monogastrics (e.g., Horse, Rabbit):

  • Esophagus → Stomach → Duodenum → Jejunum → Ileum → Large intestine → Cecum → Rectum → Anus

Ruminants: Stomach with Fermentation Vats

• Rumen:

  • Composes ~80% of the ruminant stomach in adult animals; ~30% in young animals.

  • Fermentation vat containing microorganisms (bacteria, protozoa, fungi, etc.).

  • Rumen environment:

  • Anaerobic

  • Normal temperature 39–41°C

  • pH range approximately 6.9 to 7

• Reticulum:

  • Composes about 5% of the bovine stomach.

  • Function: prevents indigestible objects from entering the stomach; known as the “hardware stomach.”

• Omasum:

  • Composes 7–8% of the bovine stomach.

  • Function: absorbs mostly water.

• Abomasum:

  • The “true” stomach.

  • Composes 7–8% of the stomach in mature animals and up to ~70% in young animals.

Quick Reference of Numbers and Proportions

• Nutrients by mass content reference:

  • 100 g of protein contains about 16\,g\ N, i.e., 16\% N by mass in protein.

• Energy contribution in diets:

  • At least 80\% of total intake should be energy-yielding sources.

• Fiber thresholds for roughages vs concentrates:

  • Roughages: >18\% crude fiber.

  • Concentrates: <18\% crude fiber.

Practical Implications and Real-World Relevance

• Diet formulation must balance energy versus protein/AA supply to meet species- and production-stage requirements.

• Ruminant nutrition focuses on maximizing rumen microbial synthesis of AA precursors and microbial protein, while non-ruminants rely more directly on dietary AA balance.

• Vitamin and mineral supplementation is tailored to species, life stage, and production goals; many vitamins can be synthesized in some animals, reducing dietary requirements (e.g., Niacin from tryptophan, Vitamin C in most species, Vitamin D with sunlight exposure).

• Nutrient sources are chosen based on digestibility and fiber content to optimize energy intake and gut health.

Summary: Foundational Principles to Remember

• Nutrients are essential for structure, energy, and regulatory functions; energy is a key driver of intake but is not itself a nutrient.

• The six major classes of nutrients are Water, Carbohydrates, Proteins, Lipids, Vitamins, and Minerals.

• Proteins provide amino acids; essential nitrogen content in protein is about 16\% by mass.

• Carbohydrates include starch (energy source) and fiber (cellulose/hemicelluloses) that affect digestibility and gut function.

• Lipids provide concentrated energy and fatty acids with saturation status affecting metabolism.

• Minerals are divided into macrominerals and trace elements with structural and catalytic roles.

• Vitamins are required in small amounts and can be fat- or water-soluble with different storage and excretion patterns.

• Energy is the major nutritional demand; diets typically allocate most resources toward energy-yielding components.

• Digestive-system design (monogastric vs ruminant) drives nutrient supply strategies and feed choices.