Lecture 2: Wildlife Food and Nutrition

Population

a group of co-existing individuals of the same species

How is energy measured?

In calories or joules (1 cal = 4.184J)

doubly labelled water method is used to measure (rate of CO2 production = measure of energy expenditure).

Highest in energy would be hare, then beaked hazelnut, then common cattail

What are the classes of nutrients and body composition of each?

1. Water (40-60%)

2. Proteins (15-20%)

3. Minerals (2-5%)

4. Vitamins

5. Carbohydrates (1%)

6. Fats (variable)

What is the order of energy content from highest to lowest?

Fats, proteins, sugars & starches, seeds, plant tissue

Water

water is obtained from three sources:

1. Free water → external sources (rivers, ponds)

2. Preformed water → from food (high in animal tissues, succulent plants, roots, tubers)

3. Metabolic water → produced in body from oxidation of organic compounds

Proteins

High molecular weight compounds made up of 25 amino acids linked together through nitrogen-carbon peptide bonds. (Nitrogen - 16%)

Essential amino acids → forms that cannot be synthesized by the animal and must be obtained in the diet

Non-essential a.a. → can be synthesized in the body

Highest rate of production of metabolic water comes from oxidation

Minerals

Macroelements → larger amount in diet (mg/g), trace element are smaller amount (ug/g)

Vitamins (definition, difference between the two and what vitamins for each)

Essential for use of energy

Fat soluble (A,D,E,K) vs. Water Soluble (C, B)

Which type of vitamin can lead to overdose toxicities?

Fat soluble (harder to dissolve)

Variation in food supply; seasonality and year-to-year

Winter → higher energy demands, less energy available

Spring → adjust breeding patterns. When food availability is highest

Fall → store fat for winter

Mast years will influence feeding behaviours and movement of different species.

What determines use of foods?

1) Physical availability → presence, abundance, plant structure, human, season

2) Physiological Factors →

i. palatability → secondary compounds chemicals that deter herbivores

ii. nutrient quality (varies with season)

Digestion

Carnivores and omnivores have their digestion in the stomache and small intestine

Herbivores have their digestion in much longer small intestines, use microrganisms, some have low metabolic rates which leads to longer retention times.

Ruminants

bovids, cervids, tylopodids (camels, giraffes).

They have a rumen which acts as the fermentation chamber. Rumen stores unchewed food for fermentation. microorganisms break down cellulose and proteins.

Hindgut fermentators

Enlarged colon/caecum holds fiber for microbial digestion.

i. Colon fermentors → parissodactyls (horses, rhinos, tapirs), larger mammals.

ii. Caecum fermentors → small mammals, have a relatively high metabolic rate.

• coprophagy → consumption of nutrient rich feces

Energy flow through body

Basal Metabolic Rate

required for basic body functions

• measured from expired air volume (remember water and CO2 as products of oxidation of fats, proteins, and carbs)

ADMR

Average daily metabolic rate = resting rate + activity rate

How do you measure the food supply?

1. Direct measures → insect traps, prey counts, clipped grass, feeding experiments. manipulating the food source.

• Problem being assuming measuring same amount animal would

2. Indirect measures → fecal protein, diet protein. mainly ungulates, observe what animal eat then determine the chemical composition of the diet. meased as fecal nitrogen (FN) - linked to protein and food quality

Body condition and nutrition

body weight as a function of body size (genetics and age) and amount of stored fat and protein

Condition indices - regression models

• foot length

• body length

1. Kidney fat - many ungulates and African ruminants

2. Bone Marrow fat - declines after most kidney fast is used. deer show rapid decline in marrow fat with low total body fat.

3. Bioelectrical impedence - uses electrical current

4. Blood and urine parameters

doubly labelled water method

rate of CO2 production = measure of energy expenditure. determines total energy (J)

Mast year

Trees and shrubs produce unusually large amounts of seeds at the same time

will influence the feeding behaviours and movements of different species

crude protein

estimate of total protein content in food based on nitrogen level

Secondary compounds

chemicals that deter herbivores