Fats (lipids)

What are lipids?

substances that are soluble in ether and other organic solvents

What is a simple lipid?

simple lipids: esters of fatty acids with alcohols (fats, oils, waxes)

What is a compound lipid?

• compound lipids: esters of fatty acids containing groups in addition to an alcohol and fatty acid —> phospholipid, glycolipid, lipoprotein

What are the classifications of lipids?

• simple lipids

• compound lipids

• derived lipids

• sterols

• tarpenes

What are phospholipids (a compound lipid)?

• a glyceride

• usually glycerol plus 2 fatty acids plus P and something

• ex: lecithins and cephalins

• surface of membrane active —> both hydrophilic and hydrophobic

What is a glycolipid?

• not really necessary in diet

• important in grasses and clovers

• much of the dietary fat of ruminants (60%) is galactolipid

• especially rich (95%) in linoleic acid

What is a cerebroside?

• nerve tissue

• fatty acid, amino group (NH2), sphingosine, and hexose

What is wax?

• fatty acid plus monohydric alcohol

• not digestible

What is steroids?

• sex hormones including cholesterol

What are tarpenes?

• have vitamin A

What is the most important category of necessary nutrients?

fats and oils

How much energy do fats contain?

fats contain 2.5 times the amount of energy as CHO

• fats = 9 Kcal/g

• proteins = 4 Kcal/g

• CHO = 4 Kcal/g

9/4 = 2.25 of energy in fats compared to proteins and CHO

What is in the composition of lipids?

• lipids composed of CHO (just like carbohydrates)

• difference is that fats contain little oxygen compared to H and C

• fats contain little oxygen because they have higher level of energy (C and H = fuel —> O is from the air)

Fats are most composed of…

glycerol and fatty acids

• triglycerides (1 glycerol and 3 fatty acids)

• diglycerides

• monoglycerides

  • glycerol (3 C alcohol)

What is the difference between saturated and unsaturated?

• saturated

  • has all the H it can have

• unsaturated

  • contains double bonds

What is a volatile fatty acid (know the NAMES)?

• 2 C atoms = acetic acid

• 3 C atoms = propionic acid

• 4 C atoms = butyric acid

Why are volatile fatty acids important?

• for rumen fermentation

  • the end product of the bacteria breaking down carbohydrates (no oxygen in the rumen so breaking down stops here)

What are long chain fatty acids (KNOW THESE)?

• 16 C = 0 = palmitic

• 18 C = 0 = stearic

• 18 C = 1 = oleic

• 18 C = 2 = linoleic

• 18 C = 3 = linolenic

• 20 C = 4 = arachidonic

What are Essential Fatty Acids?

• they are essential because the animal cannot form them = must be in animal’s diet

  • linoleic acid

  • linolenic acid

  • arachidonic acid

What are common problems with the deficiency of essential fatty acids?

• skin problems, scaly skin, and necrosis (most likely)

• necrosis of tail

• growth failure

• reproductive failure

• edema

• subcutaneous hemorrhage

• poor feathering in chicks

Essential fatty acids practical aspects (where will deficiency NOT be seen?)

• deficiency will NOT be seen on animals fed on practical diets

• deficiency will NOT be seen in ruminants (microbial benefit)

What is the function of fats being in the diet?

• energy

• provide essential fatty acids

• also for…

  • dust control (prevent dust when pouring feed in bowl)

  • absorption

  • improves palatability of some diets (adding butter to bread)

What is the difference between Omega 3 and Omega 6?

• 3

  • healthier

  • eat more fish (in some plants = canola oil)

  • 3 carbon away from double bond

• ex:

  • linoleic = 6

  • linolenic = 3

  • arachidonic = 6

What is an Omega molecule?

carbon molecule furthest away from the COOH end; also notified as the number of Carbons away from the double bond (determine if 3 or 6)

Cis vs. Trans differences?

• cis

  • good

  • natural

• trans

  • bad

  • partial hydrogenation with oils and their double bonds