Effects of Energy and Dietary Fiber on the Breast Development in Gilt.

Shengyu Xu,Haitao Xu,Yong Zhuo,Yi Yang,Zhengfeng Fang,Jianping Wang,Jian Li,Meng Cao,Bin Feng,De Wu,Lianchao Tang,Yan Lin,Xuemei Jiang,Sirun Chen,Lianqiang Che

doi:10.3389/fvets.2022.830392

Abstract

To study the effects of energy and dietary fiber on breast development in gilts and its possible mechanisms, 32 gilts (Landrace × Yorkshire) were randomly allocated into a 2 × 2 factorial design to receive a diet with low or high energy [LE: 33.37 MJ/d digestible energy (DE); HE: 41.87 MJ/d DE] and low or high fiber (LF: 0.3 kg/d dietary fiber, HF: 0.6 kg/d dietary fiber). The weight of breast tissue was recorded. The mammary glands were collected for further analyses. The high energy intake increased the relative weight of breast tissue (p < 0.05) and the content of breast fat (p < 0.05). At the same time, the oil red staining of breast slices also showed an increase in breast fat content in high-energy treatment. High energy intake increased the DNA concentration in breast tissues (p < 0.05). In addition, high energy intake increased the concentration of triglycerides, free fatty acids, and total cholesterol in the blood of gilts (p < 0.05), and the supplementation of high fiber tended to reduce free fatty acids, total cholesterol, and estradiol (p < 0.1). Proteomic analysis suggested that there were notable differences in the cytoskeleton, intracellular non–membrane-bounded organelle, apoptosis, receptor activity, and endopeptidase inhibitor activity in molecular function between the energy and fiber effects (p < 0.05). High fiber intake also decreased the mRNA expression of 5-HT7, Bax, and caspase-3 in the breast tissue of gilts (p < 0.05), which further confirmed the importance of fiber in regulating breast development in gilt. Our results indicate that increasing gilt energy intake improved breast weight and fat deposition and increased breast cell apoptosis. Increased fiber intake reduced breast fat deposition and breast cell apoptosis at high energy intake in gilts. These results provide a potential strategy for dietary intervention against high energy intake in gilts and even in humans.

Highlights

Mammary gland secretes milk to provide nutrition and immune barrier for newborns [1–3]
Our previous study found that high-energy diets increased the thickness of back fat and advanced the estrus age of gilts; at the same time, high-fiber diet intake counteracted the excessive antral follicular atresia caused by high energy intake [24]
The results showed that a high-energy diet significantly increased the concentration of TGs, free fatty acids, and TC in the blood; increased sagittal area and the relative weight of mammary glands; and increased the ether extract (EE) of mammary gland tissue of gilts

Summary

Introduction

Mammary gland secretes milk to provide nutrition and immune barrier for newborns [1–3]. The development of the mammary glands can be roughly divided into three periods, namely, early puberty (approximately 3 months), late pregnancy (about 3 months), and lactation [4–6]. Studies have shown that pregnancy is the most prosperous period of mammary gland development; Dietary Energy, Fiber, and Breast there were many studies that focused on this period [7–10]. Studies have shown that high energy intake during pregnancy has side effects on mammary gland development and subsequent lactation [12–14]. There are few studies on mammary gland development in puberty. Restricted feed intake by 20% from 90 days of age until puberty decreased growing gilts’ mammary mass of parenchymal and extraparenchymal tissues [15]. Restricted feeding from 90 days old to puberty significantly reduced mammary gland development during puberty in gilts. When the feeding amount is limited to 33% (compared with ad libitum feeding), the mammary gland weight reduced by 36.8%, and mammary DNA and RNA decreased [16]

Methods

Results

Conclusion