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Preterm neonates have an immature gut and metabolism and may benefit from total parenteral nutrition (TPN) before enteral food is introduced. Conversely, delayed enteral feeding may inhibit gut maturation and sensitize to necrotizing enterocolitis (NEC). Intestinal mass and NEC lesions were first recorded in preterm pigs fed enterally (porcine colostrum, bovine colostrum, or formula for 20–40 h), with or without a preceding 2- to 3-day TPN period ( n = 435). Mucosal mass increased during TPN and further after enteral feeding to reach an intestinal mass similar to that in enterally fed pigs without TPN (+60–80% relative to birth). NEC developed only after enteral feeding but more often after a preceding TPN period for both sow's colostrum (26 vs. 5%) and formula (62 vs. 39%, both P < 0.001, n = 43–170). Further studies in 3-day-old TPN pigs fed enterally showed that formula feeding decreased villus height and nutrient digestive capacity and increased luminal lactic acid and NEC lesions, compared with colostrum (bovine or porcine, P < 0.05). Mucosal microbial diversity increased with enteral feeding, and Clostridium perfringens density was related to NEC severity. Formula feeding decreased plasma arginine, citrulline, ornithine, and tissue antioxidants, whereas tissue nitric oxide synthetase and gut permeability increased, relative to colostrum (all P < 0.05). In conclusion, enteral feeding is associated with gut dysfunction, microbial imbalance, and NEC in preterm pigs, especially in pigs fed formula after TPN. Conversely, colostrum milk diets improve gut maturation and NEC resistance in preterm pigs subjected to a few days of TPN after birth.

A method for the analysis of potential endocrine-disrupting compounds, such as phenolic halogenated compounds (e.g., chlorinated and brominated phenols) and hydroxylated PCBs, in blood plasma is presented. Neutral halogenated compounds, specifically brominated diphenyl ethers and PCBs, are also included in the evaluation. An efficient denaturation and extraction step is described, and three methods for lipid removal are evaluated. The latter includes a nondestructive method based on high-resolution gel permeation chromatography (HR-GPC), a newly developed silica gel/sulfuric acid column, and lipid removal by sulfuric acid treatment. Recoveries, based on gas chromatography with an electron capture detector (GC-ECD), were between 70 and 90% for most of the studied compounds. The recoveries of phenolic compounds were generally slightly lower than those of the neutral compounds. The sulfuric acid treatment and silica gel/sulfuric acid column gave the highest yields for acid stable compounds, although a few target compounds were lost during that treatment and all compounds were recovered with the HR-GPC method.

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