Lecture 3 - Macronutrients (CHO) Flashcards
What are the three macronutrients?
Carbohydrates, fat, protein
What is a carbohydrate?
A combination of carbons and hydrogens - chemical structure can be open chain or closed ring
What are monosaccharides?
Stand-alone simple sugars that also act as building blocks
What are polysaccharides?
A carbohydrate whose molecules consist of a number of simple sugar molecules bonded together
What is the difference between STARCH and FIBER?
STARCHES are natural carbs that can be broken down by the mammalian body to create glucose (a primary energy source), while FIBERS are carbs from plants that are not digestible by mammalian enzymes
Name some examples of simple carbohydrates that can be consumed in the diet
Sugars, grains, and fruit
Name some examples of fiber that can be consumed in the diet
Legumes, vegetables, wheat bran, and grass/roughage
True or False: Carbohydrates (including fiber) are NOT essential nutrients for dogs and cats
True
What is the role of the “mouth” in monogastric carb digestion?
Secreting salivary amylase
What is the role of the “pancreas” in monogastric carb digestion?
Secreting pancreatic amylases, converting STARCHES to MALTOSE and GLYCOGEN to GLUCOSE
What is the role of the “small intestines” in monogastric carb digestion?
Brush border enzymes (maltase/isomaltase, lactase and sucrase) further break down carbs into simple sugars (monosaccharides)
True or False: While cats and dogs can digest and absorb carbohydrates, and they are often added into pet foods, carbohydrates are not considered essential nutrients for them
True
True or False: Cats can easily metabolize high sugar loads and will actively seek out sweet flavored foods for their taste
False; cats have a limited ability to metabolize high sugar loads, and they are unable to taste sweet flavors
True or False: Cats are constantly converting amino acids from protein to glucose in order for their body to maintain proper energy levels
True
When forestomach fermenters consume fiber (cellulose and hemicellulose) from hay, forage, and silage, how does the rumen break it down?
(Name the enzyme and whether the process is fast or slow)
Microbial cellulase, slow process
What is produced when a forestomach fermenter breaks down fiber in its rumen?
Gases (CH4 and CO2), volatile fatty acids/VFAs (acetate, propionate, butyrate), and microbial sugars
When forestomach fermenters consume starches and sugars from grain, how does the rumen break it down?
(Name the enzyme and whether the process is fast or slow)
Microbial amylase, fast process
What is produced when a forestomach fermenter breaks down starch and sugar in its rumen?
Gases (CH4 and CO2), volatile fatty acids/VFAs (acetate - LESS than in fiber digestion, propionate - MORE than in fiber digestion, butyrate), and microbial sugars
Why is the production of acetate much lower and the production of propionate much higher in ruminant starch/sugar digestion?
Propionate is the most energy efficient for the animal and helps with weight gain, while acetate is the building block for milk-fat (produces more lipids than glucose)
Compounds that aid in the efficiency of converting feed energy into usable energy by altering the rumen microfloral population to favor propionate production
Ionophores
True or False: Gaseous energy losses (like CH4 and CO2) are increased with ionophore feeding
False; gaseous energy losses are reduced with ionophore feeding
Ionophores are considered to be ______________ because they suppress growth of certain microbes in the forestomach
Antimicrobials
True or False: Ionophores are safe for ruminants, but toxic to camelids and horse
True
What effect does increased propionate have on milk production in ruminants?
Increases lactose production in the udder, which increases milk volume