Fats are Burn in a Flame of Carbohydrates
- The fatty acid molecule transforms to acetyl-CoA in the mitochondrion during beta (β) —oxidation reactions. This involves the successive release of 2-carbon acetyl fragments split from the fatty acids long chain. ATP phosphorylates the reactions, water is added, hydrogen pass to NAD and FAD, and acetyl-CoA forms when the acetyl fragment joins with coenzyme A.
- This acetyl unit is the same as that generated from glucose break down. β – Oxidation continues until the entire fatty acid molecule degrades to acetyl-CoAs that directly enter the citric acid cycle. The respiratory chain oxidizes hydrogen released during fatty acid catabolism.
- Fatty acid breakdown relates directly to oxygen uptake. Oxygen must be present to join with hydrogen for β -oxidation to proceed; oxygen must also be present to join with hydrogen.
- Without oxygen (anaerobic conditions), hydrogen remains joined with NAD and FAD and fat catabolism ceases.
Interestingly, fatty acid breakdown depends in part on a continual background level of carbohydrate breakdown.
- Recall that acetyl-CoA enters the citric acid cycle by combining with oxaloacetate to form citrate.
- Depleting carbohydrate decreases pyruvate production during glycolysis. Diminished pyruvate further reduces citric acid cycle intermediates, slowing citric acid cycle activity.
- Fatty acid degradation in the citric acid cycle depends on sufficient oxaloacetate availability to combine with the acetyl-CoA formed during β-oxidation.
- When the carbohydrate level decreases, the oxaloacetate level may become inadequate and reduce fat catabolism. In this sense, fats burn in a carbohydrate flame.
Its importance in fatty liver disease in case of cows and egg-laying hens
- These domesticated species are often getting fatty due to various reasons. The most important reason is overfeeding and the high energy density of the feed.
- Frequently imbalance of amino acids and critical vitamin-like cyanocobalamin helps in achieving such conditions. These fatty conditions lower down production and put the animal in the risk of various metabolic diseases.
- However, it’s not easy to get rid of fat from the body because fat accumulation seems irreversible deposition.
- But in high yielding cows fat mobilization would become easy due to its genetic predispositions if certain vitamins are added in feed.
Certain feeding strategies could seem
- Niacin = 892 – 2213 mg/day (ruminal escape = 1.5 – 6.2%)
- B12 (cobalamin) = 73 – 102.2 mg/day (ruminal escape = 10.0 – 37.1%)
- Choline = 10 – 20g /day (rumen-protected choline) Source of choline for phospholipid synthesis that is needed for absorption and transport of fatty acids and cholesterol. Required for synthesis of acetylcholine. Transmethylation reactions.
- Biotin = 10 -20mg /day
- Calcium propionate (150g/d) / Propylene glycol (1,2 propanediol) (200g/d) / Glycerol (1,2,3 propanediol) (165g/d)à converted to glucose in the liver and provide much needed OAA.