In dairy cows, during low milk fat syndrome, which of the following changes in metabolic process are noted?
A. Prevention of metabolism of triacyl glycerol from VLDL
B. Inhibition of release of free fatty acids from the adipose tissue by the action of hormone sensitive lipase activity.
C. Decrease in level of Methyl Malonyl CoA
D. Increase in gluconeogenesis
Choose the correct answer from the options given below:
Show Hint
Milk fat depression (MFD) is explained by the biohydrogenation theory (production of trans-10, cis-12 CLA in the rumen) and the glucogenic-insulin theory (insulin-mediated inhibition of adipose lipolysis).
Step 1: Understanding the Concept:
Low milk fat syndrome (also known as diet-induced milk fat depression, MFD) is a condition in dairy cows fed high-concentrate, low-fiber diets.
This dietary regimen alters rumen fermentation, favoring the production of propionate over acetate and butyrate. Step 2: Detailed Explanation:
Let us examine the metabolic consequences of a high-propionate, high-glucogenic diet in dairy cows: Increase in Gluconeogenesis (D): Propionate is the primary precursor for gluconeogenesis in ruminants.
An increase in propionate production in the rumen enhances gluconeogenesis in the liver, leading to elevated blood glucose levels. Inhibition of Lipolysis (B): The rise in blood glucose stimulates insulin secretion from pancreatic \(\beta\)-cells.
Insulin is an antilipolytic hormone that inhibits hormone-sensitive lipase (HSL) in adipose tissue.
This inhibition prevents the mobilization and release of free fatty acids (non-esterified fatty acids, NEFAs) from adipose tissue.
Because mammary gland uptake of circulating preformed fatty acids depends on adipose tissue mobilization, this insulin-mediated inhibition reduces the availability of fatty acid precursors for milk fat synthesis.
Therefore, options B and D describe the metabolic changes associated with low milk fat syndrome. Step 3: Final Answer:
The metabolic changes noted during low milk fat syndrome are the inhibition of free fatty acid release from adipose tissue and an increase in gluconeogenesis (B and D only).
