lecture 13 - nutritive value of feeds - fats part 2

can short chain FAs be synth in body

yes

can long chain FAs be synth in the body

no

what are linoleic and linolenic acid involved in

cell structure

energy generation

inflammation

cell signaling

what is absent in cats

Δ-6-desaturase

DHA

what do cats require

arachidonic acid and DHA supplementation

Omega 6 is pro or anti-inflammatory?

pro-inflammatory

omega 3 is pro or anti-inflammatory?

anti-inflammatory

how are FA Cs numbered

from carboxyl (delta) end or methyl (omega) end

when counting from omega end, where is the 1st double bond in an omega 3

at 3rd carbon

when counting from omega end, where is the 1st double bond in an omega 6

at 6th carbon

what is the simplest omega 6 acid

linoleic acid

what is the simplest omega 3 acid

linolenic acid

what can combined longer chained omega 3 or 6 FAs make

arachidonic acid, EPA, and DHA

most grains and forages used as feedstuff contain

low levels of fat (<5% on DM basis)

what are some byproducts that contain a higher fat content

whole cottonseed, distillers grain and solubles, fish meal

what are some sources of oils

canola, soybean, and sunflower

oilseeds are plants grown primarily for

production of edible oils from their seeds

what are the products of oilseed oil extraction

cake or meal

oil

describe the oilseed cake or meal

obtained in extraction as a rich source of protein

describe the oilseed oil

obtained by pressing seeds to extract oil

what provides a substantial proportion of fat sources used in animal nutrition

oil palms

what are some examples of oil palms

palm fat, palm oil, and palm FAs

what are some examples of fat derived from animal origins

tallow, lard, fish oil

legumes are rich in

linolenic acid

what is high in select grains, byproducts, and forages

palmitic acid and linoleic acid

all animal source fats are generally

lower in linoleic acid and higher in stearic acid compared to plant source fats

what breaks down fats in stomach

gastric lipase

what makes up an emulsion droplet

bile salts + TAGs

what breaks down fats in the small intestine

pancreatic lipase

in the rumen, what can happen to fats

they can go from unsat to sat via rumen biohydrogenation

what is often supplemented to dairy cows

C16:0

what does supplemented C16:0 do in dairy cows

↑ milk fat content, energy supply, and resistant to rumen biohydrogenation

which is easier to digest, long chain or short chain FAs

short chain

what has higher digestibility, sat or unsat FAs

unsat FAs

fat source with ______________ have higher energy value

less impurities

what are some examples of impurities in fat

mechanical debris, mineral substance, carbs, resins, oxidized FAs

how can impurities arise in fats

during fat extraction process

define crude fat

official method still used to determine the lipid content of ingredients or diets in animal nutrition

how is crude fat determined

solvent extraction with ether usually

what is crude fat referred to as

ether extract

what does acid hydrolysis do

improves release of fat from some samples

why is crude fat considered crude

nonnutritive fats are also measured which can overestimate fraction of fat with nutritional value

how can FAs be measured

by converting FAs in all lipid classes to methyl esters

how are FA methyl esters quantified

by gas-liquid chromatography which provides info on both FA quantity and profile

fat inclusion is typically low in animals relative to...

inclusion of carbs or protein

why is fat inclusion generally lower than inclusion of carbs or proteins

fat is energy dense and can negatively impact feed intake and nutrient digestibility

what is the fat inclusion of swine and poultry

5-6%

what can higher fat inclusion levels of swine and poultry do

can inhibit nutrient digestibility in small intestint

what is the fat inclusion of ruminants

3-6%

what can higher fat inclusion levels of ruminants do

can impair microbial activity and fiber digestion in rumen

what is the fat inclusion of horses

<5%

what can higher fat inclusion levels of horses

can inhibit nutrient digestibility in small intestine and microbial activity in hind gut

what is the fat inclusion of dogs and cats

diets vary widely in fat content, ~5 - ~50%

what are some animal sources of arachidonic acid for cats

animal tissues (kidney/liver) of poultry and egg yolk

how can omega 3 FAs in egg yolks be increased

feeding flaxseed and marine sources like fish meal, oil, or algae to laying hens

how can DHA be increased in milk

feeding marine source rumen protected DHA to dairy cattle