The Effects of N-acetyl Tryptophan and Omega-۳ Feeding During the Transition Period on Relative Expression of Genes Related to Endocannabinoid System in Adipose Tissue of Holstein Cows

Introduction: The transition period in dairy cows is marked by significant metabolic, endocrine, and immunological transformations, often contributing to negative energy balance and enhanced susceptibility to metabolic diseases. The endocannabinoid system (ECS) contributes to regulating energy homeostasis and inflammation, and its activation during this period has been implicated in insulin resistance and reproductive dysfunction. Materials & Methods: This research investigated the impact of dietary supplementation with omega-۳ fatty acids (۱۰۰ g/cow/day) and tryptophan (TRP) amino acid (۱۰۰ g/cow/day), and the interaction of these components, on ECS-related gene expression in Holstein dairy cow adipose tissue (AT) at day ۲۱ and ۴۲ postpartum. Cows underwent presynchronization with two injections of prostaglandin F۲α (PGF۲α) administered ۱۴ days apart. Following the second PGF۲α injection, an Ovsynch protocol was started with a GnRH injection; all cows were artificially inseminated, and pregnancy was assessed via ultrasonography on day ۳۳ post-insemination. A designated area of ۲۵ cm² (۵×۵ cm) was shaved and disinfected, and a scalpel was used to collect the subcutaneous AT sample. The obtained sample was rinsed with distilled water, and then placed into a microtube and stored at -۸۰ ° C for measuring the relative expression of genes related to the ECS: cannabinoid receptor ۱ (CNR۱), cannabinoid receptor ۲ (CNR۲), fatty acid amide hydrolase (FAAH), monoglyceride lipase (MGLL), N-acyl phosphatidylethanolamine phospholipase D (NAPEPLD), N-acylethanolamine acid amidase (NAAA), cyclooxygenase ۲ (COX۲). Results: The findings showed that the interaction of omega-۳ and TRP supplementation upregulated the relative expression of ECS-related genes, such as NAAA, FAAH, and MGLL, and downregulated the expression of CNR۲ and NAPEPLD, with no significant effects on CNR۱ and COX۲ on day ۲۱ and ۴۲ postpartum. Conclusion: These results demonstrate a synergistic effect between omega-۳ and TRP in modulating ECS activity, suppressing inflammation, and enhancing lipid metabolism. The downregulation of lipogenic and pro-inflammatory genes observed in these results supports that targeted nutritional changes can modulate ECS activity, improve negative energy balance, and enhance metabolic conditions in transition dairy cows.

کلیدواژه ها:

Endocannabinoid system (ECS) ، Negative energy balance ، Omega-۳ ، Transition cows ، Tryptophan