Document Type : Original Articles
Authors
1
Department of Animal Science, Sari Agricultural Science and Natural Resources University, Sari, Iran.
2
Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran.
3
Department of Animal Sciences, University of Florida, Florida, United States of America.
10.32598/ARI.81.2.3682
Abstract
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-3 fatty acids (100 g/cow/day) and tryptophan (TRP) amino acid (100 g/cow/day), and the interaction of these components, on ECS-related gene expression in Holstein dairy cow adipose tissue (AT) at day 21 and 42 postpartum. Cows underwent presynchronization with two injections of prostaglandin F2α (PGF2α) administered 14 days apart. Following the second PGF2α injection, an Ovsynch protocol was started with a GnRH injection; all cows were artificially inseminated, and pregnancy was assessed via ultrasonography on day 33 post-insemination. A designated area of 25 cm² (5×5 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 -80 ° C for measuring the relative expression of genes related to the ECS: cannabinoid receptor 1 (CNR1), cannabinoid receptor 2 (CNR2), fatty acid amide hydrolase (FAAH), monoglyceride lipase (MGLL), N-acyl phosphatidylethanolamine phospholipase D (NAPEPLD), N-acylethanolamine acid amidase (NAAA), cyclooxygenase 2 (COX2).
Results: The findings showed that the interaction of omega-3 and TRP supplementation upregulated the relative expression of ECS-related genes, such as NAAA, FAAH, and MGLL, and downregulated the expression of CNR2 and NAPEPLD, with no significant effects on CNR1 and COX2 on day 21 and 42 postpartum.
Conclusion: These results demonstrate a synergistic effect between omega-3 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.
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