It has been proposed that the adverse intrauterine environments can lead to fetal programming which would restrain fetal growth and development, and this effect could not completely disappear even after nutritional recovery with several weeks or months.

In China, the nutritional status of grazing ruminants is greatly influenced by seasonal factors. In general, winter (i.e., dry season) is the reproductive season of goats and sheep in China, yet nutritive value of pasture can be sub-optimal during this season. Low nutritive value of consumed pasture in winter results in low dry matter intake, consequently the supply of metabolizable energy(ME) is below the ME requirement of pregnant goats and sheep for local breeds, and consequently maternal nutritional restriction frequently occurs. This long-term effect is proposed to result from malnutrition at critical periods of fetal development leading to programming in a restricted environment of the uterus.

The researchers of Institute of Subtropical Agriculture, Chinese Academy of Sciences(ISA) divided the study into two phases: a period of nutritional restriction (gestation day 90 to parturition) followed by a period of nutritional recovery (parturition to lactation day 42) using goats. Subsequently, they collected and analyzed the samples. Eighty female goats (Liuyang black goat, local breed) were provided by Liuyang Black Goat Reproduction Center.

The researchers found that maternal protein or energy restriction decreased birth weight, and the weights of thymus, heart, abomasums, small intestine. The length of fetus from protein restriction(PR) and energy restriction(ER) were all decreased compared with that from control. When expressed relative to body weight(BW), thymus and small intestine for PR and ER still remained less than that for control. After 6 weeks of nutritional recovery, there was no difference in BW among groups; the kids from nutritional restriction groups showed a greater growth rate compared with kids from control. Moreover, liver and kidney (only in ER) were proportionally increased to BW at week 6. In a word, maternal protein or energy restriction programs the fetal growth in goats, particularly the proportional responses of fetal organs relative to BW, including thymus, small intestine, kidney and liver.

The research was supported by“The Chinese Academy of Sciences (Grant No. KZCX2-YW-455),“CAS/SAFEA International Partnership Program for Creative Research Teams (Grant No. KZCX2-YW-T07)” and “CAS Visiting Professorship for Senior International Scientists (Grant No. 2010T2S13)”.

The study entitled “Protein or energy restriction during late gestation alters fetal growth and visceral organ mass: An evidence of intrauterine programming in goats” has been published in Volume 137, Issue 3-4, March 2013 of Animal Reproduction Science, details could be found at http://www.sciencedirect.com/science/article/pii/S0378432013000092