Term
| What are the functions of adipose tissue? |
|
Definition
1. Energy store
2. Thermal insulator
3. Mechanical Shock absorber
4. Improves appearance of finished carcass
5. Improves palatability |
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Term
| What effects does adipose tissue have on meat quality? |
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Definition
Finshed Appearance (grading)
Marbling fat: tenderness, juiciness, flavour |
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Term
| Where in the body is AT located? |
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Definition
| Subcutaneous, Intermuscular, Intramuscular, in bone marrow, behind the eyeballs, Visceral (on the kidneys, heart, etc), and surrounding joints |
|
|
Term
| Explain the fetal synthesis (origin) of Adipose tissue |
|
Definition
- Mesenchyme originates from mesoderm
- Mesenchymal cells that will become adipose cells gather in 'lobules'
- Small droplets of lipid accumulate within the adipose cell precursors
- droplets congregate and form large mass of lipid in the center of the cell |
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Term
| What are two other names for adipose cell precursors? |
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Definition
| Preadipocytes, adipoblasts |
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Term
| What stimulates the growth and development of adipose cells? |
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Definition
|
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Term
| T or F: Adipoblasts are similar to fibroblasts |
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Definition
|
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Term
| Where can adipoblasts be found? |
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Definition
| Wherever the live animal would develop adipose tissue |
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|
Term
|
Definition
| Name of the cell filled with the lipid center |
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Term
| T or F: Adipocytes are lacking mitochondria, and cytoplasm |
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Definition
| False, both are present, though cytoplasm only in small amounts |
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Term
| T or F: Once adipocytes start to store triglycerides, they can no longer divide |
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Definition
|
|
Term
| What are adipose tissue depots? |
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Definition
| Accumulations of adipocytes |
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Term
| T or F: Adipose depots are not well supplied by blood capillaries |
|
Definition
| False, they ARE well supplied |
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Term
| Is there a large supply of blood vessels reaching adipose tissue? Why or why not? |
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Definition
| Yes; because BVs will deliver the adipocytes in the first place, as well as aid in it's metabolism if needed for energy |
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Term
| Do AT depots range in size? Why or why not? |
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Definition
| Yes, because large depots are required subcutaneous and visceral fat, and small amounts are required between muscle fasiculi (intermuscular fat) |
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|
Term
|
Definition
| The process of growth or enlargement by continuous build-up (e.g. Fat depots) |
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Term
| What are the two factors that affect the storing/using of AT stores? |
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Definition
| Nutritional/dietary status, and Energy requirements |
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|
Term
| Define hypertrophy, and how it relates to AT depots |
|
Definition
Hypertrophy is when the cells of a tissue enlarge causing the tissue to enlarge
Related to AT because Adipocytes enlarge if energy intake (fat) exceeds energy expenditure |
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|
Term
| What is the omentum, and where is it found? Aka? |
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Definition
| Thin CT-sack, filled with fat; Surrounds stomach and intestines; aka caul fat |
|
|
Term
|
Definition
| Thin CT membranes supporting intestines, aka lace fat |
|
|
Term
| What does the renal fat cover? |
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Definition
|
|
Term
| In steers, __% of the fat is from omentum, mesenteries, and kidney fat |
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Definition
|
|
Term
| T or F: Kidney fat is removed during dressing of beef, pork, and lamb carcasses |
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Definition
| Fals, remains in pork and lamb carcasses |
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|
Term
| What is the order that fat is stored in the body? |
|
Definition
1. Internal (visceral & kidney fat, mesenteries & omentum)
2. Subcutaneous, intermuscular
3. Intramuscular |
|
|
Term
| What is the importance of the order of fat deposition in our bodies? |
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Definition
| Order of vitality (our organs for protection, then as back-up energy reserves) |
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Term
| What are the three layers of Backfat in pigs? Describe each. |
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Definition
1. Outermost layer (first to develop; insulator)
2. Middle layer (2nd to form, thickest of the 3, most metabolically active)
3. Inner layer (last layer to form) |
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|
Term
| The perimysium is associated with which type of fat? |
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Definition
|
|
Term
| Which type of cattle have earlier fat deposition, early maturing, or late maturing? |
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Definition
|
|
Term
| T or F: Early maturing cattle are physiologically older than late maturing cattle |
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Definition
|
|
Term
| What are some characteristics of selective breeding, used to target fattening ability? |
|
Definition
| Height, body composition, onset of puberty |
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|
Term
| Which are leaner (have less fat), steers or heifers? |
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Definition
|
|
Term
| Which are leaner (have less fat), wethers or ewes? |
|
Definition
|
|
Term
| Which are leaner (have less fat), barrows or gilts? |
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Definition
|
|
Term
| Which are leaner (have less fat), gilts or boars? |
|
Definition
|
|
Term
| T or F: Intact males are leaner than castrated males |
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Definition
|
|
Term
| Define cellular hyperplasia |
|
Definition
| When cells increase in numbers |
|
|
Term
| Define cellular hypertrophy |
|
Definition
| When cells increase in size |
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Term
| What are two ways that hyperplasia can be regulated? |
|
Definition
1. Genetically (we select for low numbers (hypoplasia) to increase lean meat deposition)
2. Nutritionally (low-energy diets early in life, allows for reduced fat deposition later in life) |
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|
Term
| What is meant by the term growing rations? |
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Definition
| The desire to grow muscle and bone early in life |
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|
Term
| What is meant by the term finishing rations? |
|
Definition
| The desire to fatten or 'finish' the carcass later in life |
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|
Term
| Why doesn't the genetic selection of low numbers of adipose cells work to increase lean meat deposition? |
|
Definition
| Because adipose cells are able to be synthesized by mesenchymal cells |
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|
Term
| Why doesn't regulation using low energy diets work to increase lean meat deposition? |
|
Definition
| Because extra adipose cells can be recruited to enable compensatory growth |
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|
Term
| With regards to commercial selection, how does adipose tissue work to decreased backfat thickness? |
|
Definition
| Decreased adipocyte hypertrophy; decreased recruitment of new adipocytes |
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Term
| As amount of marbling increases, tenderness ______ (increases/decreases) |
|
Definition
|
|
Term
| What quality of meat (if high), can add increased perception of tenderness? |
|
Definition
|
|
Term
| What are two factors that affect juiciness of meat? |
|
Definition
| H2O content, Intramuscular fat |
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|
Term
| What impacts the flavour of meat? |
|
Definition
| Carbonyl compounds in AT (presence of specific FA impacts meat flavour) |
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|
Term
| In what animals is brown fat found? |
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Definition
| Newborn animals, cold-adapted animals, and hibernating animals |
|
|
Term
| True or False: brown fat can be found in poultry |
|
Definition
|
|
Term
| What is the importance of brown fat? |
|
Definition
| Temperature regulation (acts as site of heat production) |
|
|
Term
| Are brown fat cells bigger or smaller in size than white fat cells? |
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Definition
|
|
Term
| Do brown fat cells have more, or fewer mitochondria than white fat cells? |
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Definition
|
|
Term
| What organelle in the brown fat cell is responsible for it's brown colour? |
|
Definition
| The colour and number of mitochondria |
|
|
Term
| True or false: Triglycerides are found as small lipid droplets in both white and brown fat cells |
|
Definition
| False, only in brown cells |
|
|
Term
| What does a higher level of cytochromes mean for brown fat cells? |
|
Definition
|
|
Term
| Are brown fat cells more or less vascular than white fat? Why? |
|
Definition
| More, to distribute the heat from lipid oxidation and ETC reactions |
|
|
Term
| Is there more cytoplasm in brown or white cells? |
|
Definition
| Brown, with smaller droplets of fat |
|
|
Term
| When and why does brown fat disappear? |
|
Definition
| Shortly after birth, because it get's depleted warming up the body |
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|
Term
| How is heat generated in brown fat cells? |
|
Definition
| Nonshivering thermogenesis |
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|
Term
| When do we see shivering in mammals? |
|
Definition
| When there is acute exposure to cold |
|
|
Term
| When do we see heat production without shivering in mammals? |
|
Definition
| When there is chronic/prolonged exposure to cold |
|
|
Term
| What two things allow for nonshivering thermogenesis? |
|
Definition
Thryroxine (increases BMR)
Catecholamines (increase metabolism in all fats, esp brown fat) |
|
|
Term
| How does the metabolism of white fat differ from brown fat? |
|
Definition
White AT releases fatty acids into the bloodstream, which are used for ATP production
Brown fat releases heat, not energy |
|
|
Term
| Why is brown fat important for the hibernating animal? |
|
Definition
| To create warmth in the spring to enable arousal |
|
|
Term
| Define lipogenesis, and lipolysis |
|
Definition
Lipogenesis is fat synthesis
Lipolysis is fat breakdown |
|
|
Term
|
Definition
| The production of ketones (in Dairy cattle) (also in ewes, called "pregnancy toxemia," a form of ketosis |
|
|
Term
| Define the breakdown of the general structure of glycerol |
|
Definition
General structure: CH3-(CH2)n-COOH
Fats vary in length (n value from 5 to 20) |
|
|
Term
| Which have a higher melting point? UFAs or SFAs? |
|
Definition
| Saturated fatty acids, because lack of double bonds (kinks) allows for tighter bonding |
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|
Term
| Where in the body are fatty acids hydrolyzed, and by what enzyme? |
|
Definition
| Small intestine, pancreatic lipase |
|
|
Term
| In the presence of what enzyme can bile salts bind the surface of lipid droplets, to allow for lipase to bind? |
|
Definition
|
|
Term
| What happens to the fragments of the triglyceride after they have passed through the cells of the small intestine? |
|
Definition
| They reform triglycerides, gets packaged with protein and cholesterol to form a chylomicron, which get picked up by the lymphatic system, and then transported to AT |
|
|
Term
| Once a chlyomicron reaches the target adipose tissue, what happens? |
|
Definition
lipoprotein lipase acts on surface of adipose tissue cells, breaks the TGs down once more
-FFA enter the adipose cell, can reform TG's
-glycerol backbone will enter the blood stream |
|
|
Term
| How does the type of fat consumed by a monogastric influence the fatty acid content of their tissues? |
|
Definition
| If they consume MUFAs, they will deposit MUFAs in their tissues. If they consume PUFAs, then PUFAs will be deposited. |
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|
Term
| Why is feeding large amounts of plant-based unsaturated fatty acids to monogastric meat animals not desireable? |
|
Definition
| their fat depositions will consist of unsaturated fatty acids, can produce soft, runny meat which is more prone to oxidation & has shorter shelf life |
|
|
Term
| What is the hype regarding omega-3 fatty acids |
|
Definition
| protect the heart & reduce incidence of CVD |
|
|
Term
| Compare lipogenesis in pigs to lipogenesis in ruminants |
|
Definition
Pigs: use glucose to synthesize stearic & oleic fatty acids
Ruminants: use acetic acid to synthesize stearic acid |
|
|
Term
| Where does lipogenesis occur in poultry? |
|
Definition
| only in the liver, not in adipose tissue |
|
|
Term
| Why don't ruminants use glucose as a substrate for lipogenesis? |
|
Definition
| They have evolved to absorb very little glucose from the SI, so instead use VFA's produced by microbial fermentation (acetic acid in this case) |
|
|
Term
| What are repartitioning agents? |
|
Definition
feed additives which redirect energy from fattening to protein deposition
-reduce fat synthesis, increase fat breakdown
-increase protein synthesis, reduce protein breakdown |
|
|
Term
| Give two examples of beta andrenergic agonists used in Canada. What natural hormones do they mimic? |
|
Definition
Ractopamine (Paylean) for pigs
Optaflexx for cattle
Similar to epinephrine & norepinephrine |
|
|
Term
| What are the negative effects associated with beta andrenergic agonists? |
|
Definition
-tougher meat
-off colour
-negative behavioural effects, increase risk of PSE pork
-inability to cope with stress |
|
|
Term
True or False
Hormone implants are used in bulls but not steers or heifers |
|
Definition
False
Steers or heifers, NOT bulls |
|
|
Term
| Which types of hormone implants are legal in Canada? |
|
Definition
Estrogen based & combinations of estrogen & testosterone
(Strictly testosterone-based implants are not legal) |
|
|
Term
| Describe the effectiveness of estrogen-based hormone implants |
|
Definition
| -not as effective as testosterone in increasing gains & feed conversion, but don't have a negative impact on marbling to the same degree |
|
|
Term
| Describe the effectiveness of testosterone-based implants |
|
Definition
| Very effective in reducing intermuscular fat, increasing gains & feed conversion, but also decrease marbling |
|
|
Term
True or False
Milk soybean product and peas contain more estrogen than implanted beef |
|
Definition
|
|
Term
| What 3 germ lines produce cells for all tissues in the body? |
|
Definition
| mesoderm, endoderm & ectoderm |
|
|
Term
| When dressing a carcass, which animals have the kidney fat removed? |
|
Definition
|
|
Term
| What two compounds increase heat production without shivering? What are their specific actions? |
|
Definition
Thyroxine: increases BMR
Catecholamines: increases metabolism of all fats, especially brown fat |
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