Ketosis
General:
Acetyl CoA can go to Krebs, Acetoacetate (then to acetone), or b -hydroxybutyrate.Clinical Signs:
High blood ketone level
High urine ketone level
Low blood glucose
Breath smells like acetone, filtered through lungs
Causes:
1) body is dependant on gluconeogenesis (depletes OAA)
2) body mobilizing stored fat (
b -oxidation ® increase acetyl-CoA)3) Acetyl-CoA
® ketone bodiesWhen it occurs
1) starvation
2) high producing dairy cow (lactose - glu + gal), (no glu absorbed (glu)), (energy deficient - body fat - acetyl-CoA)
3) Late pregnant ewe with twins or triplets. Uterus increase - push against rumen, decrease DMI
Blood Changes:
assume dairy cow
Component |
Normal |
Ketosis |
Glucose |
52 |
28 |
Ketone |
3 |
41 |
FFA |
3 |
33 |
Treatment:
OAA precursors - enter Krebs as- propionate - succinyl-CoA
- glutamate -
- aspartate - OAA
Fatty Acid Synthesis
General:
really - but apparentlyQuassi - reverse
CHO (AA, VFA)- get acetyl-CoA - add 2 at time - get FA
1st one = 2C, then rest enter as malonyl-CoA (3C)
Acetyl-CoA + CO2 - malonyl-CoA
Basic Take-Home Points:
1.
2.
For every malonyl-CoA formed - you need:1 ATP
2 NADPH
biotin & CO2
Example:
Palmitic Acid
(16:0)8 acetyl-CoA + 7 ATP + 14 NADPH ® palmitic acid + 8 CoASH + 14 NADP + 7 ADP
Body can synthesize FA of 18C or less
Ruminant
Goal:
TG ® 3 FA + glycerol (propionate - absorbed)In rumen FFA attach to fiber particles
Block cellulase from attacking
b -1,4 bondsIncrease TG in diet decreases fiber digestion
Process:
1.
2.
bile in duodenum3.
formation of micelle4.
absorbed5.
chylomicron - to lymph (most absorbed FA to adipose)**Most FFA content of adipose does NOT represent dietary FA.
Redox State in Rumen:
Unsaturated FA
® saturated (reduction) in rumen environment60% of unsat.
® sat.2/3 of FA in beef fat = stearic acid (C18:0) = saturated
linoleic
® stearic ® reduction