Our paper highlights a crucial role for maternal nutrition—both undernutrition and overnutrition—on fetal growth and development as well as expression of the fetal genome and its lifelong consequences (fetal programming) in both livestock and humans. Importantly, we proposed a novel, unified hypothesis to explain the same pregnancy outcome, namely intrauterine growth retardation, in response to the two extremes of nutritional problems.

The Journal of Nutrition paper provides very succinct information about our recent discovery of an unusual abundance of the arginine-family amino acids in the fetal fluids of both the pig and sheep (animal models for studying human fetal development) during early pregnancy.

Intrauterine growth retardation brought about by either undernutrition or overnutrition is a significant problem in both animal agriculture and human health. In pigs, an inadequate supply of nutrients (primarily amino acids) during pregnancy results in 15-20% low-birth-weight piglets (<1.1 kg), whose postnatal survival and growth performance are severely reduced. Undernutrition in pregnant women can occur under various conditions, including a limited supply of food, severe nausea and vomiting, adolescent or closely-spaced pregnancies, placental insufficiency, or multiple fetuses resulting from assisted reproductive technologies. Strikingly, results of recent epidemiological studies indicate that almost 65% of the U.S. adult population is overweight and 31% is obese. Many overweight and obese women unknowingly enter pregnancy and continue overeating during gestation. Notably, maternal overweight or obesity increases the risk of neonatal mortality and morbidity in both domestic animals and humans. Therefore, new knowledge about the mechanisms responsible for intrauterine growth retardation will not only ensure optimal fetal development, but will also reduce the risk of chronic diseases in adults.

I have a long-standing interest in the biochemistry, nutrition, and physiology of amino acids. As a faculty member at Texas A&M University since 1991, I have been very fortunate to work with a group of outstanding Texas A&M scientists in the areas of reproductive physiology, vascular biology, and nutrition, including Drs. Fuller W. Bazer, Timothy A. Cudd, Darrell A. Knabe, Laurie A. Jaeger, Greg A. Johnson, Cynthia J. Meininger, Troy Ott, Thomas E. Spencer, and Wenbin Tuo. Particularly, over 12 years ago, Dr. Fuller W.Bazer (a Distinguished Professor of Reproductive Physiology) and Dr. Cynthia J. Meininger (Associate Professor of Medical Physiology) at Texas A&M University kindly introduced me to the fields of mammalian reproduction and vascular physiology, respectively. Thanks to the tremendous help from this highly collaborative and multidisciplinary team at Texas A&M, grant support from USDA/NRI, NIEHS, and the Texas Agricultural Experiment Station, as well as invaluable collaborations with outstanding investigators in other institutions (particularly, Dr. Steve Ford at the University of Wyoming, Dr. Sungwoo Kim at Texas Tech University, and Dr. Wilson Pond at the Baylor College of Medicine), I became involved in research on maternal nutrition and fetal growth.