adipose tissue Flashcards
importance of fat deposition
essential for life
- protects organs (like kidneys)
- fat stores result of tremendous inputs of feed energy
- fat deposited when energy inputs exceed requirements
role of carcass fats
fat no longer desirable
- calories, health concerns, alternative fatty acid sources, fat removal. wanting lean meat w superior eating quality.
classification of adipose tissue
modified connective tissue, energy store
functions of faTS
thermal insulator
mechanical shock absorber
improves appearance of a finished carcass
improves palatability/eating quality for meats
energy store fats vs CHO and protien?
2.25X energy in fats vs CHO/protien
how does adipose tissue contribute to carcass quality
gives carcass a finished appearance
beef - 2mm fat cover and marbling required to be classified as high quality beef
too much fat (beef and pork) means a lower return for producers.
what does marbling do
increase tenderness and juiciness/flavour
where is adipose tissue located
- under skin (sub Q)
- between muscles (inter muscular)
- behind eyeballs
- surface of heart and kidneys
- around joints
- in bone marrow
- abdomen
- within muscle (intramuscular)
origin of adipose tissue
fetal synthesis
mesenchyme
mesoderm cells that synthesize connective tissues
synthesis of blood, skeletal tissues, lymphatic cells, connective tissues
fibroblasts
same cells that produce collagen and elastin can produce adipose tissue, located wherever fat may develop in body
- differentiates by signals from various hormones
adipocyte
cell filled w lipid
- only small amounts of cytoplasm
= lower water content, high dry matter
mature cells >95% lipid or triglyceride
starter diet in farm animals
v concentrated in nutrients
- high nutrient requirement while feed intake is limited
(animals are efficient at converting this to gain)
growing diet in farm animal
less concentrated nutrients, still efficient at converting feed to gain, dont want fattening so more protiens in diet.
finishing diet in farm animals
least concentrated except for energy while you see highest feed intakes/day
- animals are not efficient, putting down fat, high in DM
adipose tissue depots
sites in body where adipocytes accumulate
- ranges in size (small groups intermuscular, large numbers SQ or viscerally, IM fat in loose networks close to blood vessels)
- highly vascularized to aid deposition and mobilzation
mobilization of fat
can be used by animal for energy, net fat buildup by unused energy
internal, body cavity, visceral fat function
- protect/insulate organs
- omentum (thin sheet in a large fold of connective tissue over stomach, aka caul fat)
- mesenteries (CT membranes supporting intestines, aka lace fat)
- kidney/renal fat (used as suet fat/ making dough)
- makes up 30% fat in steer
3 phases of fat deposition
1 - internal fat (visceral/kidney fat)
2 - subcutaneous
3- intramuscular (IMF)
challenge w fat deposition stages
want the IMF but not so much the SQ and internal fat
backfat in pig types
outer - insulation
middle - thickest, most active
inner - small and thin, last to form
IM - between individual muscle fibre bundles
breed diff in fattening
earlier maturing breeds are physiologically older, breeds can differ in height, body composition, onset of puberty
can be elected against fatness
sex differences in fat depostition
castrates leaner than females, leaner caracss w bulls than castrates.
body weight at fattening goes bulls- steers- heifers
cellular hyperplasia
increased cell numbers
cellular hypertrophy
increased cell size
adipose cell numbers genetically / nutritionally regulated
genetically - select for lean meat and reduced carcass fat (doesnt work)
nutritionally- giving diets early in life to make muscle, reduce fat depot later in life
brown fat
found in newborns (none in poultry)
- important so animals can produce heat during vulnerable periods. (pigs have v little so need heat pads in winter)
differs form white fat, more mitochondria.
oxidized own fatty acids.
heat production vs ATP production. produces heat but not energy.
in hibernating animal to help wake up in spring
roles for AT depots
mechanical and thermal insulation
energy storage
- anabolism (building up)
- catabolism (breaking down)
energy storage component of AT depots
related to pregame’s tox and ketosis, fats broken down = not enough energy supplied to meet requirements of the animal (lots of energy late gestation in ewes for development, lots of energy to make colostrum for cows)
what is a triglyceride
3 fatty acids bound to glycerol backbone
- often source of dietary fat in animal diets
- saturated or unsaturated.
monogastric stomach role in lipid digestion
basically nothing, begins in the mouth and then SI
ruminant stomach role in lipid digestion
actions of rumen microorganisms - they attack triglycerides.
biohydrogenation doesnt happen to all fatty acids in rumen tho
monogastric digestion/absorption of triglycerides
u r what u eat
- if you eat saturated fatty acids, you will expel saturated fatty acids. (will also be in tissues)
- high amounts of USFA will impact meat quality and carcass. leads to undesirable odors after cooking bc of oxidation
ruminant digestion/absorption of triglycerides
will deposit mostly SFA in tissues w the USFA that escaped biohydrogenation
human health, what fats do u want?
want more monounsaturated and polyunsaturated fats, feeding flax helps this.
ruminant fat digestion in the intestine compared to mono
same
ruminant fat digestion in the stomach compared to mono
different
forage vs grain finishing ruminants
diets differ in USFA content
see higher C of USFA in ruminants when feed forage vs grains
how to stop rumen microbial attack of triglycerides
coating fat - aus uses formaldehyde, increases energy early lactation
meat quality affected by fatty acid composition
shorter shelf life for unsaturated bc oxidizes easier. changes flavour
repartitioning agents
dietary additive redirects energy from fattening to protien deposition
- increases gains and feed conversion
- reduces fat synthesis and increases breakdown
- increase protien deposition
- negative effect on meat quality
- negative effect on behavioiur
implant uses?
- increase gain/feed efficiency
- decrease fat deposition
- consumers are concerned abt hormones tho
estrogen implants
legal in canada, can be mild or strong. more IMF using E rather than mix
testosterone implants
illegal in canada
combo w E is legal tho
impact of implants?
strong estrogen and androgen will provide good payback for small investment
