Benjamin Renquist

Assistant Professor
Benjamin Renquist
626-5793
Agricultural Research Center

4101 N. Campbell Ave.

Training:

  • F32 Post-doctoral Fellow – Obesity – Vanderbilt University Medical Center
    • 2008-2011
    • Mentor: Roger Cone, PhD
  • T32 Post-doctoral Fellow – Obesity – Oregon Health and Science University
    • 2007-2008
    • Mentor: Roger Cone, PhD
  • Ph.D. - Nutrition - University of California, Davis
    • 2002-2007
    • Mentors:  Christopher Calvert, PhD and Thomas Adams, PhD
  • M.S. - Animal Science - University of California, Davis
    • 2000-2002
    • Mentors:  James Oltjen, PhD and Roberto Sainz, PhD
  • B.S. - Animal Science - Colorado State University
    • 1996-2000

 

Classes Taught:

  • ANS 334 – Principles of Animal Nutrition
  • ACBS 445 – Nutritional Physiology and Metabolism

 

Lab Members:

Current:

  • Caroline Geisler, M.S. – Graduate Student
    • Projects: 
      • Role of hepatic lipid accumulation in type II diabetes and hypertension
      • Improving the genetics for feed efficiency and growth in aquaculture species
  • Kyle Kentch, M.S. – Research Specialist
    •      Projects:
      • Development of an effective, ligand directed chemotherapeutic/sterilant
      • Improving the genetics for feed efficiency and growth in aquaculture species
  • Yao Xiao, PhD – Postdoctoral Researcher
    • Projects:
      • Heat induced changes in blood flow induce hypophagia and hypogalactia
      • Role of hepatic lipid accumulation in hypertension
      • Improving the genetics for feed efficiency and growth in aquaculture species
  • Susma Ghimire, B.S. – Research Technician
    • Projects:
      • Role of hepatic lipid accumulation in type II diabetes

Previous:

  • Chelsea Hepler, M.S. – Currently a Ph.D. Student at UTSouthwestern Medical Center
  • Mark Higgins, M.S. – Enjoying golf and life in retirement.

 

Publications:

http://www.ncbi.nlm.nih.gov/pubmed/?term=renquist+bj

 

Research Interests:

Renquist Lab Research aims to address the causes and consequent diseases of obesity.  Although as scientists we are trained to limit the expectations of our findings, we unabashedly maintain that our research goal is to eliminate obesity or the pathophysiologies of obesity.  This goal is not meant as a bluster, but instead maintains our research focus on addressing a societal issue that affects nearly two-thirds of Americans.   To this end we have research focused on 1) type 2 diabetes and obesity associated hypertension, 2) development of effective, ligand directed chemotherapeutic for cancer, and 3) central nervous system control of visceral blood flow and food intake. 

  1. Hepatic lipid accumulation is directly linked to the severity and incidence of both Type II diabetes mellitus and hypertension.  Our research aims to understand the mechanism that links hepatic lipid accumulation to these pathophysiologies and develop therapeutics that target this pathway.
  2. Obesity is now the leading cause of cancer.  Development of an effective, ligand directed chemotherapeutic for cancer.  Targeted therapeutics were first proposed as the “magic bullet” by Paul Ehrlich in 1908.  By targeting a toxin specifically to the cancer cells one should be able to simultaneously increase efficacy and decrease non-specific toxicity.  Still, the promise of targeted chemotherapeutics has been elusive.  Our research aims to improve the efficacy of targeted chemotherapeutics. 
  3. Heat exposure naturally depresses food intake and simultaneously directs blood flow away from the viscera and toward the periphery to encourage environmental heat loss.  We are focused on the central nervous system signaling involved in this change in blood flow and the resulting effect on phagic drive.  We propose that a pharmaceutical mimic of heat stress may safely and effective depress food intake. 

Although obesity is the primary focus of the lab, we aim to apply our work to improve the sustainability of animal agriculture and animal welfare. To keep our attention on societal issues, our animal driven research is focused on equally robust, challenging, and large-scale goals.  To this end we have 3 projects that aim to 1) limit production losses associated with rising global temperatures, 2) improve genetics for growth and feed efficiency in aquaculture species, and 3) develop a single dose injectable sterilant. 

  1. Across production agriculture species, improved genetics for production have increased endogenous heat production, while rising global temperatures are increasing exogenous heat exposure.  Thus, addressing the role of heat load on production is primary to the maintenance of production. Heat stress suppresses food intake and milk production in the dairy cow.  The Renquist lab is focused on the role of heat induced changes in visceral and mammary gland blood flow in regulating phagic drive and milk production. 
  2. Improving the genetics for feed efficiency and growth in aquaculture species can improve production, limit environmental impact of aquaculture, and decrease reliance and overfishing of wild fish populations.  The Renquist Lab is pioneering a test that measures the metabolic rate of embryonic aquatic organisms (tilapia, oysters, and shrimp) to predict growth and feed efficiency.  The exciting results of this research can be seen in the two videos below. 
  3. Development of a single dose injectable sterilant -  Companion animal overpopulation is a world-wide animal welfare issue.  This project designed to develop a single dose injectable sterilant, funded by a Michelson Grant in Reproductive Biology, is employing GnRH-toxin conjugates to ablate gonadotropes, essential for reproduction.  Research to date has suggested that our proposed strategy can decrease the effective dose of GnRH-toxin conjugates 100 million times.

Click center of video to play

Metabolic rate of fish is directly tied to growth. The Renquist lab has begun to assess the application of this assay in embryonic fish to predict the genetic potential for growth. This assay relies on the use of the non-toxic AlamarBlue, an indicator dye that changes color from blue to pink as it interacts with an intermediate of metabolism that is directly related to metabolic rate. Thus the results are visually evident. Individuals with a high metabolic rate induce a greater color change from blue to pink than individuals with a low metabolic rate. The Renquist lab has conducted initial growth trials in tilapia, which suggest that fish with a high metabolic rate may grow up to 30% faster than those with a low metabolic rate. Further studies in tilapia are focused on the relationship between metabolic rate and feed conversion ratio.

The Renquist lab is also conducting additional studies to extend application to mollusks (oysters) and crustaceans (shrimp). In fact, preliminary studies in the oyster, conducted in collaboration with Dr. Christopher Langdon, have been the basis of 3 findings. First, inbred lines have a higher metabolic rate than outcrossed lines. Given that inbred lines are known to grow more poorly, this suggests that metabolic rate may be inversely correlated by growth in oysters. Second, the salt concentration in the water significantly alters metabolic rate. In fact, as salt concentrations vary from 10-45 parts per thousand metabolic rates increase. Finally, typical breeding schemes in oysters rely on family crosses. The Renquist lab has shown that metabolic rate variation within a family is as large as variation between families (Figure 2). Thus, selection of individuals, rather than families may allow for more rapid improvements in oyster genetics.

Considering this test can be applied in thousands of individuals in one day, it can easily be scaled up for commercial aquaculture applications. Dr. Renquist envisions that this test will be applied to select genetically superior brood stock. A youtube video describing the findings of this research is available at: https://youtu.be/N1zccCsn6C8

The research in oysters and tilapia is funded by the Western Regional Aquaculture Center and additional work in tilapia has been funded through a USDA-NIFA grant (Grant # 2015-70007-24236).