Effect of Dietary Methionine Deficiency Followed by a Re-Feeding Phase on the Hepatic Antioxidant Activities of Lambs

Abstract

Our objective was to investigate the effect of methionine restriction and resuming supply on liver antioxidant response in lambs. The concentrations of methionine and its metabolites and the expression of the nuclear factor erythroid 2-related factor 2 (Nrf2), a redox sensitive factor, were detected after methionine restriction treatment for 50 days and methionine supply recovery for 29 days. The expression of glutathione (GSH) S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were characterized at the level of transcription and translation. Methionine restriction can directly change the content of methionine and its metabolites in plasma and liver, and affect the redox state of lambs by activating the Nrf2 signaling pathway. Liver tissue can adapt to oxidative environment by upregulating the expression of antioxidant enzymes such as GSH-Px and SOD. Moreover, it was found that there was a lag effect in the recovery of metabolism after methionine supplementation.

Impacts of varying methionine to cysteine supplementation ratios on growth performance, oxidative status, intestinal health, and gene expression of immune response and methionine metabolism in broilers under Eimeria spp. challenge

“…Additionally, the current study observed that with the reduced supplemental Met to Cys ratios, the serum TAC and the liver GSH concentration linearly decreased. These results corresponded with previous studies showing that Met is essential in maintaining the antioxidant status of the animals ( Atmaca, 2004 ; Wu et al, 2017 ; Séité et al, 2018 ; Liu et al, 2020 ). Nevertheless, the current study further suggested that Met might hold greater significance than Cys in preserving the antioxidant capacity of the birds through mechanisms beyond serving as the GSH precursors since increasing Cys supplementation did not offset the decline in antioxidant capacity.…”

The Role of Organosulfur Compounds as Nrf2 Activators and Their Antioxidant Effects

“…This notwithstanding, an entire line of research supports the hypothesis that lower methionine intake reduces ROS generation and increases overall animal longevity. For instance, Liu et al [ 185 ] recently reported that dietary restriction of methionine in lambs affects the redox system, changes the content of methionine and its metabolites in the liver and plasma, and, eventually, induces Nrf2 signaling pathway activation. This apparent discrepancy in the role of methionine on the regulation or redox balance is reconciled by the observation that reduced GSH levels, consequent to methionine restriction, induce the activation of the antioxidant response through Nrf2 as a compensatory mechanism.…”