Nutritional calculations

Question 1

Catabolism

Answer 1

Breakdown of substances into smaller molecules to produce energy

Question 2

Anabolism

Answer 2

Use of stored energy to assemble new molecules

Question 3

Gluconeogenesis

Answer 3

• Protein can be converted into glucose by a process called gluconeogenesis
• Takes place in the liver
• Anabolic process

Question 4

Physiology of starvation - catabolism

Answer 4

• If patients aren’t eating, they break down substances in the body to release calories - catabolism
• In a healthy patient they catabolise body stores in this order: Glycogen to fat stores to protein stores
• In stressed patients or patients with a systemic disease, they break down body stores in a less optimal order due to high levels of circulating stress hormones which block the effects of insulin
• Insulin takes glucose to the cells
• We can refer to the breakdown of protein as protein energy malnutrition

Question 5

Physiology of starvation - GI ileus

Answer 5

• Anorexia leads to a reduction and eventually absence in gut morality (peristalsis stops)
• Commensal microbes can leave the intestines and spread to nearby areas - becoming pathogenic, including the blood stream (causing sepsis)
• This is bacterial translocation
• Also, the low pH in the stomach can lead to gastrointestinal ulceration

Question 6

Fat metabolism

Answer 6

• While glucose is the primary energy source for cell respiration, fatty acids are also used by the mitochondria to create ATP
• Longer chemical pathway than glucose
• Beta-oxidation is the process whereby fatty acids are converted into Acetyl-CoA
• The Acetyl CoA then enters the Krebs cycle

Question 7

Cachexia

Answer 7

Muscles loss associated with a disease

Question 8

Sarcopenia

Answer 8

Muscle loss with aging

Question 9

Obesity

Answer 9

• Most common nutritional disorder in the UK
• Between 35-50% of the small animal population is overweight
  Side effects of obesity:
• Increased risk of osteoarthritis
• Increased oxidative stress
• Insulin resistance
• Reduced welfare
• Decreased life span

Question 10

Fibre and obesity

Answer 10

• Dietary fibre and protein both play key roles in managing obesity as they promote satiety
• protein also helps promote muscle hypertrophy
• Increased muscle mass - increases metabolic rate

Question 11

Energy requirements of healthy animals

Answer 11

Depends on:
- Age
- Breed
- Species
- Sex
- Pregnancy
- Activity status

Question 12

Energy density terms

Answer 12

• Gross energy = the maximum energy content of a diet/food
• Digestible energy =gross energy minus energy lost in faeces
• Metabolisable energy = digestible energy minus energy lost in urine and gas production
• Net energy = metabolisable energy minus heat production associated with food consumption

Question 13

Energy measurements

Answer 13

• Calories (cal)
• Kilocalories (kcal) (most common)
• Kilojoules (kJ)
• 1 kcal = 1000 cal or 4.2 kJ

Question 14

RER calculation

Answer 14

For animals between 2-30kg:
RER = (30 x Bodyweight in kg) + 70

For animals outside that range:
RER = 70 x (BW) to the power of 0.75

• Answer given in kcal/day

Question 15

Tube feeds

Answer 15

• We calculate the patients RER then divide this into several feeds throughout the day
• e.g 4.5kg cat = (4.5 x 30) + 70 =205 kcal/day
• Then need to figure out calorie density of the food (kcal/ml)
• The majority of liquid diets have a ratio of 1kcal =1ml of food
• e.g. 205kcal (mls) / 6 feeds = 34 mls/feed