Effects of milk fat globule membrane and its various components on neurologic development in a postnatal growth restriction rat model.

BACKGROUND

Milk fat globule membrane (MFGM) is a component of breast milk that consists of glycosylated membrane-bound proteins, polar lipids and carbohydrates originating from the mammary gland plasma membrane. A commercially available bovine MFGM added to infant formula has been shown to improve cognitive development in infants at 12 months of age.

OBJECTIVE

Considering that MFGM is a complex mixture, our aim was to determine which component(s) may be leading to these cognitive outcomes.

METHODS

Growth-restricted rat pups were supplemented with one of five treatments: (a) bovine MFGM, (b) bovine phospholipid concentrate (PL), (c) sialic acid (SIA) at 200 mg/kg body weight (bw) SIA100, (d) SIA at 2 mg/kg bw and (e) nonfat milk as control. Pups were randomized, cross-fostered into litters of 17 pups per dam and supplemented from postnatal day (PD) 2 to PD 21. The following behavioral tests were performed at adulthood: T-Maze Spontaneous Alternation, Novel Object Recognition and Morris Water Maze. Hippocampus was isolated at PD14 and PD21. Expression of four genes were measured including brain-derived neurotrophic factor (BDNF), dopamine receptor 1, (Drd1), glutamate receptor (GluR-1) and ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialytransferase 4 (St8Sia4). Following behavioral testing, brains were collected for nonbiased stereology.

RESULTS

Increased expression of genes due to supplementation was most pronounced at the PD14 time point. The MFGM group exhibited higher T-Maze scores compared to the SIA group (P=.01), whereas the SIA100 group visited the novel object more frequently than the MFGM group in the Novel Object test (P=.02). No differences due to supplementation were found in the Morris Water Maze or nonbiased stereology, CONCLUSIONS: In this trial, MFGM, compared to its individual components, had the largest impact on neurodevelopment in rat pups through up-regulation of genes and improved T-Maze scores compared to the SIA group.