Early Weaning Affects Liver Antioxidant Function in Piglets.

Lihuai Yu,Yuzhu Ge,Jun Liu,Hongmin Li,Li Dong,Tianlong Wang,Zhong Peng,Hongrong Wang

doi:10.3390/ani11092679

Abstract

Simple SummaryEarly weaning is used to improve efficiency in pig production. However, early weaning may trigger liver oxidative stress in piglets. In this study, we evaluated the effects of early weaning on the development and antioxidant function of the liver in piglets. Our findings show that early weaning significantly decreases piglet body weight and suppresses liver development. We find that early weaning also suppresses the activities of superoxide dismutase (SOD) and catalase (CAT) (p < 0.05). It could be concluded that weaning may reduce the growth performance and liver antioxidant function of piglets.This study examined the impact of early weaning on antioxidant function in piglets. A total of 40 Duroc × Landrace × Large White, 21-day-old piglets (half male and half female) were divided into suckling groups (SG) and weaning groups (WG). Piglets in WG were weaned at the 21st day, while the piglets in SG continued to get breastfed. Eight piglets from each group were randomly selected and slaughtered at 24th-day (SG3, WG3) and 28th-day old (SG7, WG7). The body weight, liver index, hepatocyte morphology, antioxidant enzymes activity, gene expression of antioxidant enzymes, and Nrf2 signaling in the liver of piglets were measured. The results showed that weaning caused decreased body weight (p < 0.01), lower liver weight (p < 0.01), and decreased the liver organ index (p < 0.05) of piglets. The area and size of hepatocytes in the WG group was smaller than that in the SG group (p < 0.05). We also observed that weaning reduced the activity of superoxide dismutase (SOD) and catalase (CAT) (p < 0.05) in the liver of piglets. Relative to the SG3 group, the gene expression of GSH-Px in liver of WG3 was significantly reduced (p < 0.05). The gene expression of Nrf2 in the SG3 group was higher than that in the WG3 group (p < 0.01). The gene expression of NQO1 in the SG7 group was higher than that in the WG7 group (p < 0.05). In conclusion, weaning resulted in lower weight, slowed liver development, and reduced antioxidant enzymes activity, thereby impairing liver antioxidant function and suppressing piglet growth.

Highlights

Weaning is one of the most important periods of piglet growth and may cause weaning stress
We examined the effects of early weaning on the expression of antioxidant-related genes and antioxidant enzymes activity in weaned piglets, which are associated with Nrf2 signaling
The results showed that the body weight, liver weight, and liver index of the weaning groups (WG)

Summary

Introduction

Weaning is one of the most important periods of piglet growth and may cause weaning stress. A previous study has reported that weaning may cause liver oxidative stress in piglets, affecting liver cell apoptosis via MAPK signaling [5]. Oxidative stress is caused by reactive oxygen species (ROS), which may damage proteins, nucleic acids, and cell membranes, and affect immune responses and barrier functions in weaned piglets [7,8]. It has been reported that early weaning could reduce the activity of digestive enzymes, impair tight junctions, and damage intestinal barrier function of weaned piglets [9,10]. Some other studies have showed that the antioxidant enzymes activity is the main indicator of the liver function in weaned piglets [13,14].

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