Section 2 - Nutrition

Question 1

What are the 3 nutritional needs?

Answer 1

• Fuel for energy
• Raw materials for biosynthesis
• Essential nutrients for chemical reactions

Question 2

What are the main stages of food processing in animals?

Answer 2

Ingestion, digestion, absorption, elimination

Question 3

What are the classifications of animals (based on their eating and digestive behaviour) ?

Answer 3

Herbivores (plant material)
Carnivores ( animal material)
Omnivores (both plant and animal material)

Question 4

Describe the function of the mouth

Answer 4

Mechanical and enzymatic digestion of carbohydrates

Question 5

Describe the function of the oesophagus

Answer 5

Transports food from the mouth to the stomach via peristalsis

Question 6

Describe the function of the stomach

Answer 6

Stores and mixes food, secretes acids and enzymes for protein digestion

Question 7

Describe the function of the small intestine

Answer 7

Main site of digestion and absorption of nutrients (duodenum, jejunum, ileum)

Question 8

Describe the function of the large intestine

Answer 8

Absorbs water and electrolytes, forms and stores faeces (cecum, colon, rectum)

Question 9

What are the adaptations to the gastrointestinal tract in Herbivores?

Answer 9

Have longer digestive tracts to facilitate the breakdown of plant cellulose (e.g., rumen in ruminants).

Question 10

What are the adaptations to the gastrointestinal tract in Carnivores?

Answer 10

Have shorter digestive tracts adapted for rapid digestion and absorption of nutrients from meat.

Question 11

What are the adaptations to the gastrointestinal tract in Omnivores?

Answer 11

Have a versatile digestive system capable of processing both plant and animal material.

Question 12

What are the differences in Monogastric and Ruminant digestive tracts?

Answer 12

Monogastric (Simple Stomach):
- Single-chambered stomach (e.g., humans, dogs, pigs).
- Digestion occurs mainly in the stomach and small intestine.

Ruminant (Complex Stomach):
- Multi-chambered stomach (rumen, reticulum, omasum, abomasum; e.g., cows, sheep).
- Rumen and reticulum allow for fermentation of plant material by symbiotic microorganisms before further digestion in the stomach.

Question 13

What are some reasons for differences and similarities in monogastric and ruminant animals?

Answer 13

Dietary adaptation
Efficiency of digestion
Nutrient needs

Question 14

What is the definition of Nutrition?

Answer 14

Nutrition is providing nutrients (in the form of food) to an organism (but essentially to provide fuel and material for cell processes) to support life.

Question 15

In animals, nutrition involves:

Answer 15

Dietary intake, digestion and absorption, metabolism, health and production.

Question 16

What are the phases in the production cycle that are affected by nutrition?

Answer 16

Growth and Development:
Nutrient requirements vary with age and growth rate.

Reproduction:
Nutrient availability can affect fertility, gestation, and lactation.

Production (e.g., Milk, Eggs):
Quality and quantity of production can be influenced by diet.

Health and Disease Resistance:
Adequate nutrition supports immune function and disease resistance.

Question 17

What are the nutrient requirements?

Answer 17

Different species have different nutritional needs based on age, physiological state (e.g., pregnancy, lactation), and production goals (e.g., growth, maintenance).

Question 18

What is dry matter?

Answer 18

Dry matter refers to the solid material remaining in a substance after all free moisture (water) has been removed.

Dry matter is expressed as a percentage of the total weight of the substance.

It represents the actual nutrirumenents and components that contribute to the nutritional value of feed, forage, or other biological materials.

Question 19

Why is dry matter important?

Answer 19

Dry matter content indicates the concentration of nutrients such as carbohydrates, proteins, fats, minerals, and vitamins that are present in the material.

Question 20

Characteristics of headgut

Answer 20

Mouth, lips, teeth, tongue.

Prehension - bringing the food to the mouth.
Mastication - chewing food in preparation for digestion.
Tasting.

Question 21

Characteristics of foregut

Answer 21

oesophagus, stomach
Foregut is anything after the mouth but before the intestines. It moves food to the stomach, and mixes it, getting it in contact with the digestive enzymes. There is also absorption occurring during this stage.

Question 22

Where does fermentation occur in the ruminant?

Answer 22

Foregut (rumen)

Question 23

What is amylase?

Answer 23

A digestive enzyme that is predominantly secreted by the pancreas and salivary glands.

Question 24

How many compartments does a ruminant have, and what are their names?

Answer 24

Ruminant stomachs have four compartments:
therumen, the reticulum, the omasum and the abomasum.

Question 25

What occurs in the rumen?

Answer 25

Because of its size, the rumen acts as a storage or holding vat for feed. Aside from storage, the rumen is also a fermentation vat. The rumen’s environment favors the growth of microbes. These microbes digest or ferment feed within the rumen and make volatile fatty acids (VFAs).

Question 26

What occurs in the reticulum?

Answer 26

The main function of the reticulum is tocollect smaller digesta particles and move them into the omasum, while the larger particles remain in the rumen for further digestion.

Question 27

What occurs in the omasum?

Answer 27

The omasum is where food particles that are small enough get transferred into the abomasum for enzymatic digestion. In ruminants with a more sophisticated omasum, the large surface area allows it to play a key role in the absorption of water, electrolytes, volatile fatty acids, minerals, and the fermentation of food.

Question 28

What occurs in the abomasum?

Answer 28

The abomasum produces hydrochloric acid and digestive enzymes such as pepsin (breaks down proteins) and receives digestive enzymes secreted from the pancreas such as pancreatic lipase (breaks down fats). These secretions help prepare proteins for absorption in the intestines.

Question 29

What breaks down starch in the mouth of monogastics?

Answer 29

a-amylase

Question 30

What is pepsinogen?

Answer 30

A substance made by cells in the stomach. Acid in the stomach changespepsinogen to pepsin, which breaks down proteins in food during digestion.

Question 31

What does pancreatic lipase do?

Answer 31

Pancreatic lipase is usually secreted by the pancreas and transferred to the duodenum to participate in the hydrolysis and digestion of fat.

Question 32

What are the three rumen microbes?

Answer 32

Bacteria, Protozoa, Fungi

These microbes feed on forages ingested by the cow, and, by fermentation, produce end products that are utilised by the cow as well as by the microbes themselves for their own reproduction and cell growth.

Question 32

What does VFA stand for, and what is it?

Answer 32

VFA (volatile fatty acids) - very short, 2-5 carbons long. They are absorbed from the rumen, and are a primary energy source, estimated to provide up to 75% of the total metabolizable energy.

Question 33

What is absorption? (in context)

Answer 33

The transport of chemically simple compounds from the gastro-intestinal tract lumen, across the epithelial cells lining the gastro-intestinal tract, into the blood or lymph.

Question 34

What are the three mechanisms of absorption?

Answer 34

1. Simple diffusion
2. Facilitated diffusion
3. Active transport

Question 35

What is digestive tract structure and function?

Answer 35

Structure - mouth, oesophagus, stomach, small intestine, large intestine, rectum, anus

Function - ingestion, digestion, absorption of nutrients, and excretion of waste.

Question 36

What are the processes of digestion?

Answer 36

Mechanical digestion - chewing and churning
Chemical digestion - enzymatic breakdown of food
Absorption - uptake of nutrients into the bloodstream
Defecation - elimination of waste

Question 37

How are the digestion processes different in monogastric vs. ruminant?

Answer 37

Monogastric animals - single chamber stomach - digestion in one compartment, enzymes break down food in stomach and small intestine.

Ruminant animals - four stomach compartments (rumen, reticulum, omasum, abomasum), microbial fermentation in the rumen, food is regurgitated and chewed again

Question 38

What are the processes of metabolism?

Answer 38

Catabolism - breakdown of molecules to release energy
Anabolism - synthesis of complex molecules from simpler ones, requiring energy
Glycolysis - breakdown of glucose

Question 39

How are the metabolic processes different in monogastric vs. ruminant?

Answer 39

Monogastric - direct use of glucose and other nutrients from digestion

Ruminant - utilises volatile fatty acids from microbial fermentation, processes fibrous plant material differently

Question 40

What are the 6 components of a diet composition?

Answer 40

Water, Dry matter, carbohydrates, fat, protein, ash

Question 41

What are the primary functions of the digestive tract

Answer 41

• transport food
• digestion
• absorption
• synthesis (proteins, vitamins)
• excretion

Question 42

What is the purpose of bile?

Answer 42

To emulsify the large fat globules - this occurs in the duodenum

Question 43

Describe the physical characteristics of the four chambers of a ruminants stomach

Answer 43

Rumen - papillae lining - inc. surface area - largest compartment

Reticulum - honeycomb lining

Omasum - folded lining = large surface area

Abomasum -