Animal Nutrition Exam 2 Review

Water

Not usually thought of as nutrients but meets the definition requirements

Adequate ____ is critical to livestock production

water

2 basic functions of water for all terrestrial animals

• Major component in body metabolism

• As a major factor in body temperature control

What do all biochemical reactions that take place in an animal require?

water

Biological functions ______ property of acting as a solvent for a wide variety of compounds

water’s

Many compounds ionize readily in ____.

water

Water serves as what type of medium?

As a medium for transportation of semisolid digesta in the GI tract

• Various solutes: blood, tissue fluids, cells, secretions, and in excretions such as urine and sweat

Water provides _____ of cell contents and body fluids so that relatively free movement of chemicals may occur within the cells and  in the fluids and GI tract

dilution

Is water a product or substrate in hydrolysis?

substrate

Is water a product or substrate in oxidation?

product

Metabolic water is also known as _____

water of oxidation

Per gram of food, what is much higher for fat than for protein or carbohydrates? 

metabolic water produced

What macronutrient produces the most metabolic water?

fat

What does metabolic water result from?

Oxidation of organic components in the cells of the body

What properties of water allow it to have an effect on temperature regulation?

• High specific heat

• High thermal conductivity

• High latent heat of vaporization

What do the properties of water affecting temperature regulation allow for?

• Accumulation of heat

• Ready transfer of heat

• Loss of large amounts of heat on vaporization

What liquid has the highest specific heat?

water

What does a higher specific heat allow?

greater capacity to store heat

How are sudden changes in body temperature avoided?

through the high specific heat of water

What is readily absorbed from most sections of GI tract?

water

Osmotic relationships within particular organs have ____

a marked effect on absorption

How does an increase in solutes in digesta (e.g. post-meal) affect osmotic pressure?

it increases osmotic pressure

What is body water influenced by?

age of animal & amount of fat in tissues

When body water is expressed on basis of fat-free body, water content is relatively constant across species with an average percentage of ____.

~73%

Is the greatest amount of water in body tissues present as intracellular or extracellular fluids?

intracellular fluids

Where is the remaining body water located?

the contents of GI tract & urinary tract

Amount of body water present in GI is variable are greatly affected by _____.

feed consumption

Body water decreases with ____ and has an inverse relationship with ____.

age; body fat

Is body water higher or lower in lactating cows than dry cows?

higher

Extracellular water is _____ in male calves than female calves of the same age.

greater

How much energy is required in passive diffusion?

little to no energy

Water easily passes through cell membranes & flows based on ______.

osmotic or hydrostatic pressure gradients

What extracellular fluids does water absorbed in the GI tract enter?

blood and lymph

What are volume & osmotic pressure regulated by?

thirst & antidiuretic hormone

What is water turnover used to express?

rate at which body water is excreted & replaced in tissues

Where is water available to animal’s tissues derived from?

• Drinking water

• Water contained in or on feed

• Metabolic water

• Water liberated from metabolic reactions such as condensation of amino acids to peptides

• Preformed water associated with body tissues catabolized during a period of negative energy balance

Water content of _____ is highly variable

feedstuffs

As moisture content increase, what happens to water intake?

water intake decreases presenting an inverse relationship

Insensible water

water lost via vaporization from lungs & dissipation through skin

What do birds excrete instead of urea?

uric acid

Obligatory water

minimal amount of water required for excretion

What may loss of water be affected by?

fecal loss, insensible water loss, exhalation loss, & loss via sweat

When is drinking usually induced?

dehydration of body tissues, but can occur when there is no apparent need:

• dry mouth/throat from reduced salivary flow

• blood plasma volume

• osmotic receptors 

• for satiety

What happens to feed consumption when temperatures reach stressing levels?

feed consumption decreases and water consumption increases

What is dry matter intake highly correlated with?

water intake at moderate temperatures

How do higher levels of protein affect water intake?

more water intake because of greater urinary excretion of excess urea

How does increased fat content affect water and salt intake?

increase water intake as well as increased salt intake

What environmental factors affect water intake?

• High temperature

• High humidity

• Design of water dispensers 

  • Location

  • Ease of access

  • Cleanliness

Animals consume ___ kg of water for every 1 kg of dry feed.

2-5 kg

How does decreased water quality affect water intake and feed consumption?

decrease in consumption and thus a decrease in feed consumption

What organization is responsible for upper acceptable limits of pesticide in water?

EPA

Concentrations of ____ are usually tolerated but _____ can easily reach toxic levels

nitrate; nitrite

What are carbohydrates major components in?

plant tissues

Why is the process of chloroplasts synthesizing carbs & oxygen vital for animals?

because they could not exist without this transformation of energy and free oxygen produced

How are carbohydrates classified?

on basis of number of carbon atoms per molecule of carbohydrate and basis of the number of molecules of sugar in the compound

Hexose

6-carbon sugar

Pentose

5-carbon sugar

Sugars

carbs strung together at varying lengths

What do carbohydrate primarily serve as in animals?

source of energy for normal life processes

What do carbohydrates primarily serve as in plants?

simple sugars (glucose and ribose) are involved in energy transformations and tissue synthesis

Glycans

complex carb with an important role in transmitting biochemical signals into/between cells

What are the 2 major sources of energy for the animal body?

carbs & lipids

What is the only macronutrient with no established minimum requirement for humans?

carbs

What is the ultimate source of energy for most animal cells?

glucose

What type of carbs are the only type that can be absorbed from the GI tract (except in newborns)?

monosaccharides

What increases with plant age?

lignification

What is the chief structural component in mature trees?

lignin

In ruminants and other species with large microbial populations, what does anaerobic fermentation of carbs produce?

large quantities of volatile fatty acids (VFA)

What part of small intestine has the greatest capacity to absorb monosaccharides?

Upper or proximal section of small intestine (duodenum + jejunum)

While arabinose is absorbed at the lowest rate, what two sugars are absorbed at highest rate due to established active transport?

galactose & glucose

How is glucose transported against its concentration gradient?

by coupling with sodium

Do sodium-glucose co-transporters move glucose across cell membranes with or against its concentration gradient?

against

Do facilitative glucose transporters move glucose across cell membranes with or against its concentration gradient?

with

What is fructose converted by the intestine to?

lactic acid

What type of inhibition occurs between galactose & glucose during transport across intestinal mucosal cells?

competitive inhibition

What are 2 well-understood ways to influence glucose absorption?

• Reduced by short-term fasting

• Increased by chronic restricted food intake

What happens as a result of the deficiency of specific disaccharides in GI tract?

serious GI upset

Endogenous (fecal metabolic) losses result in a net (apparent) absorbability approximating 80% or more in nonruminant animals. What does this mean?

Meaning, except in cases of illness, absorption of soluble carbs is similar for a wide variety of carb sources

Rate of digestion of starch can be influenced by particle size, nature of starch, interactions of starch with protein and fat and the presence of ______

antinutrients such as phylate, tannins, saponins, and enzyme inhibitors

While the body stores little energy in the form of carbs, some ______ is converted to _______, which is stored in liver and muscle tissue

glucose; glycogen

What processes allow animals maintain the narrow acceptable window of blood glucose to prevent hypo- & hyperglycemic events?

glycogenesis←→glycogenolysis

What hormones from the pancreas control blood sugar levels?

insulin & glucagon

Glycogenesis

glucose→glycogen; requires 2 ATP molecules for every 1 molecule of glucose

Gluconeogenesis

pyruvate→glucose; formed by body tissues of liver & kidneys

Glucogenic amino acids

• Arginine

• Methionine

• Cystine

• Histidine

• Threonine

• Tryptophan

• Valine

• All nonessential amino acids

Glucogenic

amino acids that give net rise to glucose when metabolized through gluconeogenesis

Ketogenic

gives rise to ketones

Ketogenic amino acids

leucine

Which type of animal, ruminants or nonruminants, constantly depend on gluconeogenesis to meet glucose needs?

ruminants

Which type of animal, ruminants or nonruminants, depend on acetate production from fermentation as major product of digestion?

ruminants

Which type of animal, ruminants or nonruminants, absorb glucose directly?

nonruminants

Which type of animal, ruminants or nonruminants, do not rely on gluconeogenesis except in long term meal deprivation?

nonruminants

What do amino acids used for gluconeogenesis or for energy enter the citric acid cycle as?

acetate, pyruvate, or α-ketoglutarate

What are the key sources of C atoms for glucose synthesis by gluconeogenesis?

lactate & pyruvate

Glycolysis

is the metabolic pathway that converts glucose into pyruvate, generating energy in the form of ATP and NADH in the process

Glycogen storage is _____

limited

What happens when ingestion of carbs exceed current needs for glycogen formation?

glucose is converted to fat

What pathway handles most glucose-6-phosphate metabolism?

glycolytic (Embden-Meyerhof) pathway

Pyruvate

an important metabolite in glucose and lipid metabolism

What is significant about the further metabolism of Acetyl-CoA occurs in Krebs or Citric acid cycle?

final common energy pathway for carbohydrate, fat, and carbon skeletons of amino acids