Ruminant

Goal: TG ® 3 FA + glycerol (propionate - absorbed)

In rumen FFA attach to fiber particles

Block cellulase from attacking b -1,4 bonds

Increase TG in diet decreases fiber digestion

Process:

1. TG released from fiber particles in acid (HCl) of abomasum

2. bile in duodenum

3. formation of micelle

4. absorbed

5. chylomicron - to lymph (most absorbed FA to adipose)

**Most FFA content of adipose does NOT represent dietary FA.

Redox State in Rumen:

Rumen is highly reduced

Unsaturated FA ® saturated (reduction) in rumen environment

60% of unsat. ® sat.

2/3 of FA in beef fat = stearic acid (C18:0) = saturated

linoleic ® stearic ® reduction

PROTEIN

General: ~100,000 different proteins in the body. Protein is present in every cell. Body is ~80% protein on a dry fat-free basis. Primary function of CHO & lipid is energy, BUT protein is different.

Function:

1. Structural (skeletal muscle, connective tissue, protective protein)

2. Specialized functions (enzymes, hormones, blood proteins)

3. Energy - AA converted to Krebs cycle intermediates

Hogs - starving - use protein for energy (glucose can be made from some aa)

 Composition: C,H, O, N some have S, and (or) P, [ALL have N]

Range 14-20% N for proteins, AVG. = 16% (100/16 = 6.25)

Kjeldahl N= allows us to measure N content Þ %N X 6.25 = %Crude Protein

True protein is comprised up of Amino Acids. Polymer (many units) of amino acids.

We eat protein because our body needs AA

Dietary AA ® AA in intestinal lumen ® AA in blood ® Tissue Protein

Amino Acids

There are about 20 AA we are concerned with for this class.

All ~100,000 different proteins are comprised of several combinations of these proteins.

General Structure:

a -carbon is the most reactive

R-group = what gives the AA individuality to the 20 different AA

Properties: Serve in two capcities

Carboxyl group = has acid properties Þ donates H in solution

Amino group = has base properties Þ accepts H in solution

Dissolve AA in neutral solution (pH = 7.0), can act as an acid or a base ("Zwitter ion")

Classification

Chemical (R-group) Method = based on properties of R group

1) Neutral = R group is uncharged (monoamino, monocarboxyl)

2) Acidic = R group contains more carboxyl than amino (neg. charge)

3) Basic = R group contains more amino than carboxyl (pos. charge)

4) Sulfur = R group is/contains S

5) Aromatic = R group has a ring structure