Changes in gene expression of metabolically active proteins in ruminal epithelium of lambs fed with oil and monensin


Department of Animal Sciences, Faculty of Agriculture, University of Zanjan, Zanjan, Iran


BACKGROUND: High grain diets in ruminants increases the risk of digestives disorders such as acidosis which may lead to high economic loss. OBJECTIVES: This experiment was conducted to determine the effects of an unsaturated and polyunsaturated fatty acid and monensin on gene expression of enzymes involved metabolic pathway of cell proliferation and rumen epithelial intracellular pH regulation. METHODS: Twenty two male Afshari lambs with live body weight of 45 ± 8 kg and six month age were used in a completely randomized design with 3 treatments replicates for 77days including 21 days adaptation period. Experimental diets were consisted of a basal high concentrate diet (16% CP and 2.75 Mcal/kg ME) and 1) no additive (control, C= 8 lambs), 2) 30 mg monensin/day/head during the whole experimental period (T1= 8 lambs), and 3) (polyunsaturated fatty acidduring the whole experimental period (T2 = 6 lambs). Lambs were killed after 77 days on the treatment diets. RESULTS: Compared with the C treatment, relative abundance of mRNA of monocarboxylate transporter isoforms MCT1, MCT4 and the ketogenic enzyme 3-hydroxy-3 methyl-glutaryl CoA-synthase (HMGCS2) were higher for the T1 treatment. The expression of cholesterolgenic enzyme HMGCS1 was down-regulated for the T1 treatment and that of HMGCS1 was up- regulated for the T2 treatment. The expression of MCT1 and MCT4 were down-regulated for the T2 treatment. Monensin had an additional impact on the mRNA abundance of epithelial SCFA- and acid-base transporters with concurrent changes in rumen epithelial thickness. CONCLUSIONS: The results suggest that adding monensin and oil as nutritional means to reduce acidosis cause changes in mRNA expression of VFA transferring proteins and limiting enzyme in the synthesis of cholesterol and Ketone bodies in the rumen epithelium.


Aschenbach, J.R., Bilk, S., Tadesse, G., Stumpff, F., Gabel. G. (2009) Bicarbonate - dependent and bicarbonate – independent mechanisms contribute to nondiffusive uptake of acetate in the ruminal epithelium of sheep. Am J Physiol Gastrointest Liver Physiol. 296: G1098-G1107.
Baldwin, R. L. (1998) Use of isolated ruminal epithelial cells in the study of rumen metabolism. J Nutr. 128: 293S–296S.
Bevans, D.W., Beauchemin, K.A., Schwartzkopf-Genswein, S.K., McKinnon, J.J., McAllister, T.A. (2005) Effect of rapid or gradual grain adaptation on subacute acidosis and feed intake by feedlot cattle. J Anim Sci. 83: 1116-1132.
Dempsey, M.E. (1974) Regulation of steroid biosynthesis. Ann Rev Biochem. 43: 967–990.
Dengler, F., Rackwitz, R., Benesch, F., Pfannkuche, H., Gäbel, G. (2013) Bicarbonate-dependent transport of acetate and butyrate across the basolateral membrane of sheep rumen epithelium. Acta Physiol. (Oxf.). doi: 10.1111/apha.12155.
Ellis, J.L., Dijkstra, J.,  Bannink, A.,  Kebreab, E.,  Hook, S.E.,  Archibeque, J. (2012) France high-grain-fed beef cattle Quantifying the effect of monensin dose on the rumen volatile fatty acid profile in high-grain-fed beef cattle. J Anim Sci. 90: 2717-2726.
Firth, S.M., Baxter, R.C. (2002) Cellular actions of the insulinlike growth factor binding proteins.  Endocr Rev. 23: 824–854.
Gäbel, G., Aschenbach, J.R. (2006) Ruminal SCFA absorption: channelling acids without harm. In: Ruminant Physiology: Digestion, metabolism and impact of nutrition on gene expression, immunology and stress. Sejrsen, K., Hvelplund, T., Nielsen, M.O. (eds.). (1st ed.) Wageningen Academic Publishers. The Netherlands.
Gäbel, G., Aschenbach, J.R., Müller, F. (2002) Transfer of energy substrates across the ruminal epithelium: implications and limitations. Anim Health Res Rev. 3: S. 15-30.
Harmon, D.L., Gross, K.L., Krehbiel, C.R., Kreikemeier, K.K., Bauer, M.L., Britton, R.A. (1991) Influence of dietary forage and energy intake on metabolism and acyl-CoA synthetase activity in bovine ruminal epithelial tissue. J Anim Sci. 69: 4117-4127.
Hegardt, F.G. (1999) Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase: a control enzyme in ketogenesis. Biochem J. 15; 338. Pt 3: 569-82.
Huntington, G.B. (1990) Energy metabolism in the digestive tract and liver of cattle: Influence of physiological state and nutrition. Reprod Nutr Dev. 30: 35–47.
Kirat, D., Masuoka, J., Hayashi, H., Iwano, H., Yokota, H., Taniyama, H., Kato, S. (2006) Monocarboxylate transporter 1 (MCT1) plays a direct role in short-chain fatty acids absorption in caprine rumen. J Physiol. 576.Pt. 2: 635-47.
Kirat, D., Matsuda, Y., Yamashiki, N., Hayashi, H., Kato, S. (2007) Expression, cellular localization, and functional role of monocarboxylate transporter 4 (MCT4) in the gastrointestinal tract of ruminants. Gene. 391: 140–149.
Liao, J.K., Laufs, U. (2005) Pleiotropic effects of statins. Ann Rev Pharmacol Toxicol. 45: 89–118.
Meredith, D., Christian, H.C. (2008) The SLC16 monocarboxylate transporter family. Xenobiotica. 38: 1072–1106.
Müller, F., Huber, K., Pfannkuche, H., Aschenbach, J., Breves, G., Gabel, G. (2002) Transport of ketone bodies and lactate in the sheep ruminal epithelium by monocarboxylate transporter 1. Am J Physiol Gastrointest Liver Physiol. 283:  G1139–G1146.
Murray, K.R., Granner, K.D. (2003) Cholesterol synthesis, transport and excretion. In: Harper’s Illustrated Biochemistry (26rd ed.). New York, USA. p. 219-231.
Mütter, G.L., Zahrieh, D., Liu, C., Neuberg, D., Finkelsrein, D., Baker, H.E., Warrington, J.A. (2004) Comparison of frozen and RNALater solid tissue storage methods for use in RNA expression microarrays. BMC Genomics. 5: 88.
Naeem, A., Drackley, J.K., Stamey, J., Loor, J.J. (2012) Role of metabolic and cellular proliferation genes in ruminal development in response to enhanced plane of nutrition in neonatal Holstein calves. J Dairy Sci. 95: 1807–1820.
Nagaraja, T.G., Titgemeyer, E.C. (2007) Ruminal acidosis in beef cattle: The current microbiological and nutritional outlook. J Dairy Sci. 90: 17–38.
Nagaraja, T.G., Newbold, C.J., Van, C., Nevel, J., Demeyer, D.I. (1997) Manipulation of ruminal fermentation. In: The rumen microbial ecosystem. Hobson, P.N., Stewart, C.S. (ed.). (2nd ed.) P523. Kluwer academic publishers, Dordrecht. The Netherlands.
Nocek, J.E. (1997) Bovine acidosis. implication on laminitis. J Dairy Sci. 80: 1005-1028.
Penner, G.B., Aschenbach, J.R., Gabel, Rackwitz, G.R., Oba, M. (2009)  Epithelial capacity for apical uptake of short chain fatty acids is a key determinant for intraruminal pH and the susceptibility to subacute ruminal acidosis in sheep. J Nutr. 120-1714: 39, 9.       
Pfaffl, M.W. (2001) A new mathematical model for relative quantification in real-time RT–PCR. Nucleic Acids Res. 1: e45.
Plazier, J. C., Krause, D. O., Gozho, G. N. and McBride, B. W. (2008) Subacute ruminal acidosis in dairy cows: The physiological causes, incidence and consequences. The Vet. J. 176: 21-31.
Russell, J.B., Strobel, H.J. (1989) Effect of Ionophores on Ruminal Fermentation. Appl Environ Microbiol. 54: 872-877.
Schlau, N., Guan, L.L., Oba, M. (2013) The relationship between rumen acidosis resistance and expression of genes involved in regulation of intracellular pH and butyrate metabolism of ruminal epithelial cells in steers. J Dairy Sci. 95: 5866-5875
Steele,  M.A., AlZahal, O., Walpole, M.E., McBride, B.W. (2012a) Short communication: Grain-induced subacute ruminal acidosis is associated with the differential expression of insulin-like growth factor-binding proteins in rumen papillae of lactating dairy cattle. J Dairy Sci.  95: 6072–6076.
Steele,  M.A., Dionissopoulos, L., AlZahal, O., Doelman, J., McBrid, B.W. (2012b) Rumen epithelial adaptation to ruminal acidosis in lactating cattle involves the coordinated expression of insulin-like growth factor-binding proteins and a cholesterolgenic enzyme. J Dairy Sci. 95: 318–327.
Steele, M.A., Vandervoort, G., AlZahal, O., Hook, S.E., Matthews, J.C., McBride, B.W. (2011a) Rumen epithelial adaptation to high-grain diets involves the coordinated regulation of genes involved in cholesterol homeostasis.  Physiol Genomics. 43: 308–316.
Steele, M.A., Greenwood, S.L., Croom, J., McBride, B.W.  (2012c) An increase in dietary non-structural carbohydrates alters the structure and metabolism of the rumen epithelium in lambs. Can J Anim Sci. 92: 123-130.
Steele, M.A., Croom, J., Kahler, M., AlZahal, O., Hook, S.E., Plaizier, K., McBride, B.W. (2011b) Bovine rumen epithelium undergoes dramatic structural adaptations during grain-induced ruminal acidosis epithelial adaptation. Am J Physiol Integr Comp Physiol.  300: R1515–R1523.
Toral, P.G., Shingfield, K.J., Hervás, G., Toivonen, V., Frutos, P. (2010) Effect of fish oil and sunflower oil on rumen fermentation characteristics and fatty acid composition of digesta in ewes fed a high concentrate diet. J Dairy Sci. 93: 4804–4817.