Effects of Intrauterine Growth Retardation on Development of the Gastrointestinal Tract in Neonatal Pigs

Abstract

Background: Intrauterine growth retardation (IUGR) is a common problem in human and other species and increases the risk of death of the fetus and newborn during the perinatal period. Objectives: This study was conducted to examine the influences of intrauterine growth retardation (IUGR) on development of the gastrointestinal tract in newborn pigs. Methods: Ten animals from five litters were divided into five piglets with IUGR and five with normal birth-weight (NW). The IUGR category comprised animals with a birth weight 2 SD below the mean birth weight of the total population, while the NW category included animals with a birth weight within one SD of the mean birth weight in the total population. Animals were anesthetized and sampled within 2–4 h after birth and without suckling. The morphological changes of intestine and stomach of IUGR piglets were compared with NW ones. The expressions of IGF-I and receptors for growth hormone and insulin in intestinal mucosa were semiquantified using reverse transcription PCR. Results: The results of our study indicated that the weights of the stomach, small intestine and small intestinal mucosa were significantly lower in IUGR compared with NW piglets (p < 0.01). In addition, the lengths of the small intestine and colon in IUGR pigs were also significantly less than those of NW (p < 0.05). Furthermore, insulin-like growth factor-I (IGF-I) mRNA level in intestinal mucosa of IUGR piglets was increased significantly (p < 0.05), and the expression mRNA levels of insulin receptor and growth hormone (GH) receptor in the mucosa in IUGR piglets showed a tendency to be lower (p = 0.17 and p = 0.11, respectively) than those of the NW animals. Conclusion: We conclude from the data that IUGR affects intestinal growth and morphology and is in associated with altered gene expression of growth-related proteins. We speculate that the morphological change and associated altered endocrine homeostasis contribute to lower growth rates of pigs affected by IUGR.

Identifying the limitations for growth in low performing piglets from birth until 10 weeks of age

“…LP piglets might be a middle category in terms of anatomical development between IUGR and average weight piglets in the litter. The small intestine of LP piglets was proportionally longer, thinner, but heavier per g of ingested feed when compared with HP piglets, at 10 weeks of age, in line with other studies (Wang et al, 2005 in IUGR piglets). These findings led us to speculate that LP piglets had an increased surface to absorb nutrients in the intestinal tract, in agreement with the findings of Han et al (2013) for IUGR piglets.…”

Growth and development of adipose tissue and gut and related endocrine status during early growth in the pig: impact of low birth weight

“…In VLBW neonatal piglets, the relative weight of the pancreas is reduced, whereas that of the stomach, small intestine or colon is only slightly affected (Table 2). Moreover, intrauterine growth retardation is associated with a reduction in the wall thickness of the stomach, small intestine and colon and in the density of the small intestine and colon (Table 2; Xu et al, 1994;Wang et al, 2005). Consequently, the intestinal surface area for absorption is highly reduced, the average number of villi per unit area and the height of villi being 15% to 20% lower in VLBW than in MBW piglets (Table 3).…”

“…Hormonal regulation of intestinal development seems to be affected by intrauterine growth retardation. Indeed, in association with an altered intestinal morphology, intrauterine growth-retarded piglets have a lower mucosal IGF-I gene expression than controls, whereas they tend to express less GH and insulin receptors than controls (Wang et al, 2005).…”

Ghrelin in the gastrointestinal tract and blood circulation of perinatal low and normal weight piglets

“…In the gastric mucosa of rodents, the ghrelin cells (GCs) get distributed from the glandular base to the glandular neck when rat pups grow older (Sakata et al, 2002b). Its perinatal presence and important physiological and endocrine functions indicate that ghrelin might play a role in the gastrointestinal development and possibly also in its IUGR-associated adaptations (Wang et al, 2005). Only a few studies describe the role of ghrelin in the development of the gastrointestinal system of newborn and suckling animals (Kotunia and Zabielski, 2006).…”

“…The porcine model represents most of the symptoms associated with the metabolic syndrome in adult life seen in the IUGR children, such as increased adiposity (Poore and Fowden, 2004) and glucose intolerance (Poore and Fowden, 2002). In addition, the IUGR alters gastrointestinal morphology in the postnatal piglets (Xu et al, 1994;Wang et al, 2005;D'Inca et al, 2010b). However, it is not known whether these alterations persist until weaning.…”