1 Saed HAR, et al. Vet Rec Open 2020;7:e000339. doi:10.1136/vetreco-2019-000339 Relationship between expression pattern of vitamin D receptor, 1 alpha- hydroxylase enzyme, and chemokine RANTES genes and selected serum parameters during transition period in Holstein dairy cows Hala A R Saed, 1 Hussam M M Ibrahim , 2 Sabry A El-Khodery , 2 Mohamed A Youssef 2 Food/farmed animals 1 Department of Internal medicine, Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt 2 Department of Internal Medicine, Infectious and Fish Diseases, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt Correspondence to Dr Hussam M M Ibrahim; hussam-habosha@mans.edu.eg To cite: Saed HAR, Ibrahim HMM, El-Khodery SA, et al. Relationship between expression pattern of vitamin D receptor, 1 alpha-hydroxylase enzyme, and chemokine RANTES genes and selected serum parameters during transition period in Holstein dairy cows. Veterinary Record Open 2020;7:e000339. doi:10.1136/ vetreco-2019-000339 Received 25 January 2019 Revised 24 November 2019 Accepted 27 November 2019 © British Veterinary Association 2020. Re-use permitted under CC BY-NC. No commercial re-use. Published by BMJ. ABSTRACT Objectives The objective of the present study was to evaluate the pattern of genetic expression of vitamin D receptor (VDR), 1 alpha-hydroxylase (1α-OHase) enzyme and chemokine regulated on activation normal T-cell expressed and secreted (RANTES) in peripheral blood of Holstein dairy cows during transition period. Methods Blood samples were collected from 16 Holstein dairy cows at 3 weeks prior expected date of delivery (EDD), at the day of parturition, and 3 weeks post-partum for assessment of expression profle of studied genes using real-time PCR and measurement of glucose, ionized calcium (Ca), parathyroid hormone (PTH), inorganic phosphorous (P), sodium (Na), potassium (K), chloride (Cl), and magnesium (Mg) levels. Results Compared with 3 weeks prior EDD, VDR gene expression decreased signifcantly at the day of parturition then increased signifcantly at 3 weeks post-partum. The genetic expression of 1α-OHase enzyme as well as PTH, K, Na and Cl levels increased signifcantly at the day of parturition. The Ca level decreased signifcantly at the day of parturition then increased signifcantly at 3 weeks post-partum. The P level increased signifcantly at the day of parturition then decreased signifcantly at 3 weeks post-partum. Glucose level decreased signifcantly at the day of parturition and at 3 weeks post-partum. RANTES gene expression showed non-signifcant changes among the three different time points. The expression of VDR gene had a negative correlation with the expression of 1α-OHase enzyme gene, and serum levels of glucose, PTH, P and K, but had a positive correlation with the serum Ca level. The expression of 1α-OHase enzyme gene had a positive correlation with serum levels of PTH, P and K, but had a negative correlation with the serum Ca level. Conclusions Results of the current study indicate the importance of monitoring the genetic expression of VDR and 1α-OHase enzyme as indicators of metabolic changes during transition period, suggesting that they are candidate genes to judge the health status of dairy cows during such period. INTRODUCTION Transition period, period from the last 3 weeks prior parturition till 3 weeks after parturition, is the most critical period during the dairy cattle production life. 1 During such period, dairy cows start extensive metabolic alterations of glucose, fatty acids, vitamins and minerals metabolism to support both the coming fetus and the onset of lactation. 2 Several elements are implicated in building up the final picture of this period, either to pass smoothly or to fall in multifaceted metabolic and inflammatory disorders. In this regard, cows endure several endogenous homeostatic mechanisms displayed by minor and major elements, side by side to hormonal mechanisms aiming to protect transition cows from the risk of several disorders. 3 Vitamin D 3 , an essential pro-hormone produced in the skin by ultraviolet irradia- tion of 7-dehydrocholesterol, is rapidly reha- bilitated in the liver to 25-hydroxyvitamin D (25-(OH)D 3 ) by the aid of several cyto- chrome P450 enzyme systems, mainly the sterol 27-hydroxylase (CYP27A1). 4 5 1,25-Dihydroxyvitamin D3 (1,25-(OH) 2 D 3 ), an active form of vitamin D, is formed primarily in the kidney by enzymatic hydroxylation of (25-(OH)D 3 ) with the aid of cytochrome P450 27B1 enzyme (CYP27B1) which is simply well known as the 1 alpha-hydroxylase (1α-OHase) enzyme. 6–8 Numerous cells and tissues other than renal tissue were found to share 1α-OHase enzyme expression. Extra renal activation of vitamin D 3 by mononuclear cells in the peripheral blood has been docu- mented in response to infectious and inflam- matory disorders. 8–10 Therefore, synthesis of on January 13, 2020 by guest. Protected by copyright. http://vetrecordopen.bmj.com/ Vet Rec Open: first published as 10.1136/vetreco-2019-000339 on 9 January 2020. Downloaded from