Samer El-Kadi

My research interest is primarily to elucidate the underlying factors that contribute to macronutrient metabolism. My research is centered on two areas. One research area has focused on understanding why amino acids are catabolized excessively by splanchnic tissues (mainly liver and intestines), and whether dietary or physiologic factors such as amino acid supplies or muscle growth could affect their metabolism. To get insight into the partitioning of amino acids to anabolic and catabolic pathways we are using the multi-catheterized ruminant model and primary epithelial cell culture in combination with stable isotope dilution and ¹³C-mass isotopomer distribution analysis (¹³C-MIDA) techniques. Another area has focused on investigating the in vivo regulation of protein turnover in growing pigs. To achieve this goal we are applying a multifaceted approach that combines protein expression and targeted metabolite analyses to measure protein synthesis and degradation in muscles. The immediate objectives are to improve our understanding of how amino acids are utilized and how protein synthesis and degradation are controlled in the growing animal. The overarching goal is to identify areas where novel dietary or management interventions could be used to enhance growth and improve the efficiency with which amino acid are deposited in muscles.

Refereed Publications (*indicates student under my supervision)

For a full and up-to date publication list please follow this link: https://scholar.google.com/citations?user=M4ENRyYAAAAJ&hl=en&oi=sra

1)    El-Kadi SW, Boutry C, Suryawan A, Gazzaneo MC, Orellana RA, Srivastava N, Nguyen HV, Kimball SR, Fiorotto ML, Davis TA.  Intermittent bolus feeding promotes greater lean growth than continuous feeding in a neonatal piglet model. American  Journal of Clinical Nutrition. 2018; 108, 830-841.

2)    El-Kadi SW, Chen Y*, McCauley SR*, Seymour KA*, Johnson SE, Rhoads RP.  Decreased abundance of eIF4F subunits predisposes low-birth-weight neonatal pigs to reduced muscle hypertrophy.  Journal of Applied physiology. 2018; 125, 1171-1182.

3)    Chen Y*, McCauley SR*, Johnson SE, Rhoads RP, El-Kadi SW. Downregulated translation initiation signaling predisposes low-birth-weight neonatal pigs to slower rates of muscle protein synthesis. Frontiers in Physiology. 2017; 8, 482. https://doi.org/10.3389/fphys.2017.00482.

4)    Chen Y*, Zhu H*, McCauley SR*, Zhao L, Johnson SE, Rhoads RP, El-Kadi SW.  Diminished satellite cell differentiation and S6K1 expression in myotubes derived from skeletal muscle of low birth weight neonatal pigs. Physiological Reports. 2017; 5:e13075.

5)    Hamad S, Kim S, El-Kadi SW, Wong Eric, Dalloul R. Comparative expression of host defense peptides in turkey poults. Poultry Science. 2017; 96, 2083–2090.

6)    Rhoads R, Baumgard L, El-Kadi SW, Zhao L. Roles for insulin supported skeletal muscle growth. Journal of Animal Science. 2016; 94:1791-1802.

7)    Davis TA, El-Kadi SW, Boutry C, Suryawan A, Fiorotto ML. Timing of nutrient delivery impacts muscle protein synthesis and lean growth.  Energy and Protein Metabolism and Nutrition; 2016: European Association of Animal Production publication No. 137, Jacek Skomial and Hélène Lapierre, eds. Wageningen Academic Publishers, Wageningen, the Netherlands; 2016. p. 25-6.

8)    Boutry C, El-Kadi SW, Suryawan A, Steinhoff-Wagner J, Stoll B, Orellana RA, Nguyen HV, Kimball SR, Fiorotto ML, Davis TA. Pulsatile delivery of a leucine supplement during long-term continuous enteral feeding enhances lean growth in term neonatal pigs. American Journal of Physiology – Endocrinology and Metabolism. 2016; 310, E699-E713.

9)    Wheatley SM, El-Kadi SW, Suryawan A, Boutry C, Orellana RA, Nguyen HV, Davis SR, Davis TA. Protein synthesis in skeletal muscle of neonatal pigs is enhanced by administration of β-hydroxy-β-methylbutyrate. American Journal of Physiology – Endocrinology and Metabolism. 2014; 306: E91-99.

10) Boutry C, El-Kadi SW, Suryawan A, Wheatley SM, Orellana RA, Kimball SR, Nguyen HV, and Davis TA. Leucine pulses enhance skeletal muscle protein synthesis during continuous feeding in neonatal pigs. American Journal of Physiology – Endocrinology and Metabolism. 2013; 305:E620-631.

11) El-Kadi SW, Gazzaneo MC, Suryawan A, Orellana RA, Murgas-Torrazza R, Wilson FA, Srivastava N, Nguyen HV, Fiorotto ML, Kimball SR, and Davis TA. Viscera and muscle protein synthesis in neonatal pigs is increased more by intermittent bolus than continuous feeding. Pediatric Research. 2013; 74:154-162.

12) Holder VB, El-Kadi SW, Tricarico JM, Vanzant ES, McLeod KR, Harmon DL. The effects of crude protein concentration and slow release urea on nitrogen metabolism in Holstein steers. Archives of Animal Nutrition. 2013; 67:93-103.

13) El-Kadi SW, Boutry C, Suryawan A, Gazzaneo MC, Orellana RA, Srivastava N, Nguyen HV, Fiorotto ML, and Davis TA.  Lean accretion and protein turnover are enhanced by intermittent bolus feeding in neonatal pigs. European Association of Animal Production publication No. 134, Oltjen J, Kebreab E, Lapierre H, eds. Wageningen Academic Publishers, Wageningen, the Netherlands. 2013; p. 427-8.

14) Boutry C, El-Kadi SW, Suryawan A, Wheatley SM, Orellana RA, Nguyen HV, and Davis TA.  Supplementation with a leucine pulse during continuous feeding stimulates protein synthesis and suppresses protein degradation pathways in skeletal muscle of neonatal pigs. European Association of Animal Production publication No. 134, Oltjen J, Kebreab E, Lapierre H, eds. Wageningen Academic Publishers, Wageningen, the Netherlands. 2013; p. 415-6.

15) El-Kadi SW, Suryawan A, Srivastava N, Orellana RA, Nguyen HV, Lobley GE, and Davis TA. Anabolic signaling and protein deposition are enhanced by intermittent as compared with continuous feeding in skeletal muscle of neonates. American Journal of Physiology – Endocrinology and Metabolism. 2012; 302:E674-86.

16) Suryawan A, Murgas Torrazza R, Gazzaneo MC, Orellana RA, Fiorotto ML, El-Kadi SW, Srivastava N, Nguyen HV, and Davis TA. Enteral leucine supplementation increases protein synthesis in skeletal and cardiac muscles and visceral tissues of neonatal pigs through mTORC1-dependent pathway. Pediatric Research. 2012; 71:324-331.

17) Gazzaneo MC, Suryawan A, Orellana RA, Murgas Torrazza R, El-Kadi SW, Wilson FA, Kimball SR, Srivastava N, Nguyen HV, Fiorotto ML, and Davis TA. Intermittent bolus feeding has a greater stimulatory effect on protein synthesis in skeletal muscle than continuous feeding in neonatal pigs. Journal of Nutrition. 2011; 141:2152-2158.

18) Murgas Torrazza R, Suryawan A, Gazzaneo MC, Orellana RA, Frank JW, Nguyen HV, Fiorotto ML, El-Kadi SW, and Davis TA. Leucine supplementation of a low-protein meal increases skeletal muscle and visceral tissue protein synthesis in neonatal pigs by stimulating mTOR-dependent translation initiation. Journal of Nutrition. 2010; 140:2145-2152.

19) Bequette BJ, El-Kadi SW, and Sunny NE. Intermediary metabolism and neogenesis of nutrients in farm animals. In: Energy and Protein Metabolism and Nutrition. European Association of Animal Production publication No. 127, Crovetto GM, eds. Wageningen Academic Publishers, Wageningen, the Netherlands. 2010; p. 99-109.

20) Koontz A, El-Kadi SW, Harmon DL, Vanzant ES, Matthews J, Boling J, and McLeod KR. Effect of ractopamine on whole body and splanchnic energy metabolism in Holstein steers. Canadian Journal of Animal Science. 2010; 90:77-85.

21) El-Kadi SW, Baldwin RL VI, McLeod KR, Sunny NE, Owens SL, and Bequette BJ. Glutamate is the major anaplerotic substrate in the tricarboxylic acid cycle of isolated rumen epithelial and duodenal mucosal cells from beef cattle. Journal of Nutrition. 2009; 139:869-875.

22) El-Kadi SW, McLeod KR, Elam NA, Kitts SE, Taylor CC, Harmon DL, Bequette BJ, and Vanzant ES. Nutrient net absorption across the portal-drained viscera of forage-fed beef steers: Quantitative assessment and application to a nutritional prediction model. Journal of Animal Science. 2008; 86: 2277-2287.

23) McLeod KR, El-Kadi SW, Harmon DL, and Vanzant ES. Amino acid and energy metabolism by the portal-drained viscera of beef steers: quantitative relationships with metabolizable energy intake. In: Energy and Protein Metabolism and Nutrition. European Association of Animal Production Publication No. 124, Ortigues-Marty I, eds. Wageningen Academic Publishers, Wageningen, the Netherlands. 2007; p. 343-4.

24) Baldwin RL, El-Kadi SW, McLeod KR, Connor EE, and Bequette BJ. Intestinal and ruminal epithelial and hepatic metabolism regulatory gene expression as affected by forage to concentrate ratio in bulls. In: Energy and Protein Metabolism and Nutrition. European Association of Animal Production Publication No. 124, Ortigues-Marty I, eds. Wageningen Academic Publishers, Wageningen, the Netherlands. 2007; p. 293-4.

25) Sunny NE, Owens SL, Baldwin RL VI, El-Kadi SW, Kohn RA, and Bequette BJ. Salvage of blood urea nitrogen in sheep is highly dependent upon plasma urea concentration and the efficiency of capture within the digestive tract. Journal of Animal Science. 2007; 85:1006-1013.

26) El-Kadi SW, Baldwin RL, Sunny NE, Owens SL, and Bequette BJ. Intestinal protein supply alters amino acid, but not glucose, metabolism by the sheep gastrointestinal tract. Journal of Nutrition. 2006; 136:1261-1269.

27) Bequette BJ, Sunny NE, El-Kadi SW, and Owens SL. Application of stable isotopes and mass isotopomer distribution analysis to the study of intermediary metabolism of nutrients. Journal of Animal Science. 2006; 84:E50.

28) El-Kadi SW, Sunny NE, Owens SL, and Bequette BJ. Glucose metabolism by the gastrointestinal tract of sheep as affected by protein supply.  In: Progress in Research on Energy and protein Metabolism. European Association of Animal Production publication No 109, Soufrant WB and Metges CC, eds. Wageningen Academic Publishers, Wageningen, the Netherlands. 2003; p. 401-4.