Exam 2 Flashcards
Describe, in details, lipid digestion and transport across the intestinal lining.
When lipids enter the rumen they will be broken down through lipolysis and hydrogenation lipods will be then broken down later in the SI by pancreatic lipase and bile salts into the micelles. These micelles will eventually be broken down to smaller particles known as chylomicrons. Chylomicrons will be dumped into the lymphatic system which will then be spread throughout the body by blood.
Describe how VFAs are produced and metabolized.
In ruminants VFAs are broken down into 3 main acids.
Acetic acid, propionic acid, and butyric acid are the end products through fermentation of starches and fibers. Pyruvate forms lactic acid, acetic acid, and fornic acid.
Lactic acid -> propionic acid (propionate)
Acetic acid -> butyric acid (butyrate)
Fornic acid -> waste
Acetic acid acid is the most abundant and used by mammary gland for milk production.
Propionic acid will go through TCA cycle to form glucose
Butyric acid will be used to make ketone bodies
Describe the major events regarding tissue origins and post- secretory metabolic transformation of lipoproteins within plasma compartment in ruminants
lipoproteins include chylomicrons, VLDL, IDL, LDL, and HDL CHYLOMICRONS
VLDL are used for energy because they are more available and low density.
VLDL -> IDL -> LDL
LDL is used for cholesterol transfer by LDL receptors
HDL is the most abundant and used primarily for cholesterol transport
Explain the events that take place in the body when a cow receives a dietary N source
When ruminants receive a N source it will be broke down in the rumen by rumen microbes. This will cause ammonia and CO2. Depending on the energy levels needed and the leftover N will determine how much ammonia will be leftover. Ammonia is converted to urea and brought to the Liver. Some urea will be brought back to rumen through saliva. The remaining will continue and be brought out the body through urine. Rumen Protected N sources will be broken down in Abomasum and SI. It will then be absorbed through the SI
VLDL is a major transporter of
VLDL is assembled in the liver from triglycerides, cholesterol, and apolipoproteins. VLDL transports endogenous products, whereas chylomicrons transport exogenous (dietary) products.
Very-low-density lipoprotein (VLDL) is the transporter of endogenous triglyceride (TG), and, ultimately, through its metabolic product,
What is the major function of apolipoprotein CII
Plays an important role in lipoprotein metabolism as an activator of lipoprotein lipase.
- Protein component of the lipoprotein.
- stabilizes the lipoprotein
- allows lipoproteins to be recognized by receptors on cell surfaces
- stimulates LPL to remove lipids from the lipoproteins
Major source(s) of glucose in the body include
- our body is maintained within a narrow range by the humoral control and a ‘lipostat’ system
- regulated by leptin from adipose tissues
- keeps our accumulated fat stores in check
- Any disturbance in this delicately poised homeostasis could be disastrous as it can lead to obesity and its associated metabolic manifestations
Which one of the following VFAs is most affected when there is low supply of succinate
Propionic acid production was increased by an acid adapted. These were lactate, fumarate, and succinate metabolites that are known to influence propionic acid synthesis.
Name three major functions of rumen microorganisms
Microbial protein production, degradation of feedstuff, transport
What are the major functions of butyric acid
Butyrate: mostly derived from acetate it is not a direct production in it a acetic acid put together. Important in ketones usage as energy. Metabolized by rumen epithelium to ketone bodies. In house energy source. Produces more energy than anything else. Important for ketogenesis. Most of it get absorbed through the rumen wall.
Briefly explain main characteristics of chylomicron compared to that of VLDL
Chylomicrons: These are large triglyceride rich particles made by the intestine, which are 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
Very low density lipoproteins (VLDL): produced by the liver and are triglyceride rich.
- Similar to chylomicrons the size: VLDL particles can vary depending on the quantity of triglyceride
- Triglyceride production in the liver is increased
- secreted VLDL particles are large: VLDL particles are smaller than chylomicrons
Methane production in the rumen is an important event because
Methane is an especially potent trace gas due to its global warming potential, 25 times that of carbon dioxide, and its 12-year atmospheric lifetime; it is the second largest anthropogenic greenhouse gas, behind carbon dioxide. Methaneis produced in the rumen as a product of normal fermentation of feedstuffs.
Which VFA has shown the lowest impact on feed intake
Absorption
Acetate: 70% rumen lumen, 20% ruminal wall, 50% portal vein
Propionate: 20% rumen lumen, 10% ruminal wall, 10% portal vein
Butyrate: 10% rumen lumen, 9% ruminal wall, 1% portal vein
Which one is the important precursor for synthesis of “butyric acid” in the ruminal carbohydrate degradation?
- originate from the catabolism of triglycerides
- from lactate fermentation by clostridia
- saturated short-chain fatty acid with a 4-carbon backbone
- commonly found in esterified form in animal fats and plant oils.
- produced by both chemical and biochemical routes.
- based on a biochemical method using anaerobic fermentation by Clostridial spp.
Which one of the following catalyzes the synthesis of acetyl Co-A
glycolysis -> pyruvate -> acetyl CoA -> citric acid cycle
The mitochondrial pyruvate dehydrogenase complex then catalyzes the oxidative decarboxylation of pyruvate to produce acetyl-CoA.
Another important use of acetate is as the major source of acetyl CoA for synthesis of lipids.
