Fatty acid synthesis from lactate in growing cattle

Area of Science:

• Biochemistry
• Animal Science
• Metabolic Physiology

Background:

• Adipose tissue is central to energy metabolism and fat deposition in livestock.
• Understanding lipogenesis in cattle is key to optimizing meat quality and animal growth.
• Enzyme activities and substrate utilization change during bovine development.

Purpose of the Study:

• To investigate fatty acid synthesis rates from lactate and acetate in different bovine adipose tissues.
• To determine the developmental changes in lipogenic and NADPH-generating enzyme activities.
• To elucidate the primary pathway for cytosolic acetyl-CoA generation in bovine adipocytes.

Main Methods:

• Quantification of fatty acid synthesis rates using radiolabeled substrates (lactate and acetate).
• Assay of key lipogenic enzymes, including acetyl-CoA carboxylase and ATP-citrate lyase.
• Measurement of NADPH-generating enzyme activities across different adipose depots.
• Comparison of these parameters in cattle aged 11 to 19 months.

Main Results:

• Fatty acid synthesis from both lactate and acetate increased with age in subcutaneous and intermuscular adipose tissues.
• Intramuscular adipose tissue showed continuous acetate-driven synthesis increase, while lactate-driven synthesis increased until 17 months.
• NADPH-generating enzyme activities peaked early (11-13 months) and stabilized; acetyl-CoA carboxylase activity remained constant.
• ATP-citrate lyase activity increased with age, particularly in intramuscular depots, supporting lactate-derived fatty acid synthesis.

Conclusions:

• Bovine adipose tissue exhibits significant developmental changes in lipogenic capacity.
• Lactate is a key substrate for fatty acid synthesis in growing cattle.
• The citrate cleavage pathway is likely the predominant route for generating cytosolic acetyl-CoA for lipogenesis from lactate in bovine adipose tissue.