Final Flashcards
Explain functions of each compartment of the ruminant stomach
- Rumen- storage, fermentation, microbial degradation and protein production
- Reticulum- scratch factor, form feed bolus for rechewing and regurgitation
- Omasum- Filter, doesn’t let too large of particles through and water absorption
- Abomasum- true stomach, produces HCl for break down and digestion of feeds as well as other enzymes that acid in breakdown
What are the advantages and disadvantages of having an established protozoa population in the rumen?
Adv.
Increased cellulose digestion- 25-33% of total cellulose dig
Mechanisms- provide more NH3 to bacteria, remove O2
Slower fermentation of starch and sugars
Greater VFA production
Disadv.
increased rumen protein turnover
increased CH4 production
development of more virulent strains of pathogenic bacteria
Explain animal- and feed-related factors that affect feed intake
Physical fill: distention of the gut tells the animal to stop eating
Chemostatic: absorbed nutrient in blood is monitored by receptors in brain - tells animal to stop eating
What is the main function of Acetate
Acetate: mostly from cellulose
- Important for milk fat synthesis
- Cellulolytic bacteria
- Energy source for rumen epithelium and muscle
- Not utilized by liver
What is the main function of propionate
Propionate: mostly from starch
- Important to produce glucose
- Amylolytic bacteria
- Utilized by rumen epithelium
- Converted to lactate and pyruvate
- Important as a precursor for gluconeogenesis
What is the main function of Butyrate
Butyrate: mostly derived from acetate
- Important in ketones usage as an energy source
- Metabolized by rumen epithelium to ketone bodies (acetoacetate, beta-hydroxybutyrate)
- Later metabolized in liver
- Net ATP production is 25 per mole
Explain main characteristics of chylomicron
- large triglyceride rich particles
- made by the intestine
- involved in the transport of dietary triglycerides and cholesterol to peripheral tissues and liver.
- size of chylomicrons varies depending on the amount of fat ingested
- A high fat meal: large chylomicron
Explain main characteristics of VLDL
- Very low density lipoprotein
- are used for energy because they are more available and low density.
- Delivers endogenous lipids from the LIVER to FAT and MUSCLE cells with the help of LPL
- Becomes IDL
- Mostly triglycerides
Explain main characteristics of LDL
LDL: Low Density Lipoprotein
- used for cholesterol transfer by LDL receptors
- Delivers fat and cholesterol to cells (including arteries)
- Mostly Cholesterol- neg. impact, Atherogenic; Increases risk for heart disease
Explain main characteristics of IDL
IDL: Intermediate Density Lipoprotein
- Transient
- Little nutritional impact
- TAGs are removed…becomes LDL
- Mostly Triglycerides
Explain how each of the main VFA is produced in the rumen
• produced in large amounts through ruminal fermentation
• provide greater than 70% of the ruminant’s energy supply
• Acetic, proprionic and butyric acids formed in the rumen
- absorbed across the ruminal epithelium, from which they are carried by ruminal veins to the portal vein and hence through the liver.
1. Acetic acid is utilized minimally in the liver and is oxidized throughout most of the body to generate ATP.
2. Proprionic acid is almost completely removed from portal blood by the liver. Within the liver, proprionate serves as a major substrate for gluconeogenesis.
3. Butyric acid, most of which comes out of the rumen as the ketone beta-hydroxybutyric acid, is oxidized in many tissues for energy production.
Name all the factors that affect heat production (HP) and explain each in detail.
Factors that affect heat prod: Gender, nutrient absorbed, physiological state, ration characteristics, environmental conditions, GI tract, physical activity
Gender: basal met rate
Nutrient Absorbed: glucose is more efficient on cellular level
Physiological state: fetal growth, growth of animal
Ration characteristics: forage vs concentrate
Environmental conditions: thermoneutral zone
GI tract: ruminants vs monogastrics, bigger tracts require more maintence
Physical activity: grazing is less efficient than confined
Explain how Vitamin D, Ca, P are related
- When blood calcium is low= The parathyroid glands release parathyroid hormone (PTH), Stimulates conversion to calcitriol (active form)
- Increased active form of vitamin D: Increased absorption of calcium in the intestines, Increased reabsorption of calcium in the kidneys, Increased bone turnover (calcium is released from the bones)
- Calcitonin – promotes ossification of phosphorus onto matrix
- PTH – promotes resorption of phosphorus from bone and excretion in urine
- Calcitriol – promotes increased phosphorus absorption in the intestine
Explain how Vitamin E and Se are related
Part of glutathione peroxidase (antioxidant effects), High levels of vitamin E or selenium may inhibit the other’s effects, closely working with vitamin E, Antioxidant, incorporated into proteins to make selenoproteins, which are important antioxidant enzymes.
What are ionophores? Explain a) the mode of action, b) their advantages, and c) name two examples
Define: a lipid-soluble substance capable of transporting specific ions through cellular membranes.
Mode of Action: compounds that alter rumen fermentation patterns. They disrupt the ion concentration gradient across microorganisms.
Advantages: increase feed efficiency and body weight gain, higher feed intake with similar feed conversion
Examples: vancomycin and nigericin