Glucosamine Supplementation in Premating Drinking Water Improves Within-Litter Birth Weight Uniformity of Rats Partly through Modulating Hormone Metabolism and Genes Involved in Implantation.

Cuiping Feng,Dandan Han,Shiyu Tao,Junjun Wang,Shilan Wang,Taolin Yuan,Ting Liu

doi:10.1155/2020/1630890

Abstract

Within-litter birth weight variation in multiparous animals has become a big issue due to high incidence of low birth weight neonates, which gives rise to high preweaning mortality and morbidity. Foetus with various birth weights is the outcome of diverse embryos competence which is affected by oocyte quality. Glucosamine (GlcN) has been reported to be involved in oocyte maturation; however, its effect on pregnant outcomes remains unknown. The present study was conducted to investigate the effects of premating GlcN supplementation via drinking water on within-litter birth weight variation and its underlying mechanism. Fifty eight Sprague-Dawley female rats were randomly assigned to one of two groups with normal drinking water or drinking water supplemented with 0.5 mM GlcN from six to eight weeks old. Variation of within-litter birth weight in the GlcN group was 5.55%, significantly lower compared with 8.17% in the control group. Birth weight was significantly increased in the GlcN group (2.27 ± 0.06) compared with the control group (2.08 ± 0.04). Both absolute and relative weights of the ovary at the end of GlcN treatment were higher in the GlcN group than in the control group (P < 0.05). In the GlcN group, there were more successfully implanted blastocysts (13.38 ± 0.63 and 15.75 ± 0.59 in the control and treatment group, respectively) with more uniform distribution along the two uterine horns compared with the control group. Besides, gene expressions of Alk3 and Bmp2 were increased in the implantation sites, while IGF-1 and Mucin-1 were decreased significantly in rats administrated with GlcN. Maternal progesterone, estradiol, and IGF-1 concentrations on D 19.5 were significantly increased, while insulin and total cholesterol levels were significantly decreased in contrast with control dams. In summary, the administration of 0.5 mM GlcN solution before mating reduced within-litter birth weight variation, accompanied with increased fetal weight. Further investigation indicated that the improved outcome of pregnancy results at least partly from the increased ovary weights of the rats, the homogeneous embryo developmental competence, the enhanced receptivity of the uterine environment, and the adjusted maternal hormone levels.

Highlights

Poor postnatal survival and retarded growth performance induced by low birth weight and high within-litter birth weight variation in litter-bearing animals have been recognized for many decades [1, 2]
Within-litter birth weight variation was statistically lower in the GlcN supplement group than in the control group (5.55% for 0.5 mM GlcN, 5.77% for control group, respectively), and average litter weight of live-born rats in the 0.5 mM GlcN-supplemented group (2.27 ± 0.06) was significantly higher than that from the control group (2.02 ± 0.04)
GlcN is preferentially utilized as a substrate to form extracellular matrix hyaluronic acid, which is involved in the expansion of cumulus-oocyte complexes (COCs), mucification, and oocyte maturation in vitro [20,21,22]. e increased absolute and relative weight of the ovary indicated a better oocyte quality or more developed follicles in the GlcN group relative to controls [8]

Summary

Introduction

Poor postnatal survival and retarded growth performance induced by low birth weight and high within-litter birth weight variation in litter-bearing animals have been recognized for many decades [1, 2]. Birth weight variation can be influenced by many factors including breed, maternal physiology, and nutrition. E external environment of females before and during pregnancy, including nutrient intake, dietary behavior, temperature, and health condition, has a significant influence on oocyte and embryo development [3]. Changes in the amount and composition of food or BioMed Research International diet consumed before mating can affect oocyte maturation, blastocyst production, prenatal survival, and the number of surviving offspring [4]. Maternal physiological conditions, especially lipid metabolism and hormones, play important roles in pregnancy results. During oocyte maturation or early embryonic development, diet-induced changes in maternal fatty acids may impact follicles and embryo quality [5]. Fatty acids are precursors of steroids and prostaglandins, and they are important for regular reproductive functions [6]

Methods

Results

Conclusion