Comparative proteomic analysis of the effects of high-concentrate diet on the hepatic metabolism and inflammatory response in lactating dairy goats

Abstract

BackgroundTo understand the impact of feeding a high-concentrate diet to mid-lactating goats for a long time on liver metabolism and inflammatory response, two dimensional polyacrylamide gel electrophoresis (2-DE) and real-time PCR method were employed to detect proteins differentially expressed in liver and their mRNAs expression in goats fed high concentrate diet (HC) or low concentrate diet (LC). Twelve lactating dairy goats were randomly assigned to either a HC diet group (65 % concentrate of dry matter; n = 6) or a LC diet group (35 % concentrate of dry matter; n = 6) for 10 wk.ResultsTwenty differentially expressed spots (≥2.0-fold changes) in the hepatic tissues were excised and successfully identified using MALDI TOF/TOF. Of these, 8 proteins were up-regulated, while the rest 12 proteins were down-regulated in HC goats compared to LC. Differential expressed proteins including alpha enolase 1 (ENO1), glutamate dehydrogenase 1 (GLUD1), glutathione S-transferase A1 (GSTA1), ATP synthase subunit 5β (ATP5β), superoxide dismutase [Cu-Zn] (SOD1), cytochrom c oxidase subunit Via (COX6A1) and heat shock protein 60 (HSP60) were further verified by real-time PCR and/or western blot at mRNA or protein expression level. Consistent with the 2-DE results, a significant decrease of β-actin protein expression and SOD enzyme activity was observed in liver of HC goats (P < 0.05), while ENO1 protein expression was significantly up-regulated in HC compared to LC goats (P < 0.05) . However, western blot analysis did not show a significant difference of hepatic HSP60 protein between HC and LC group, which did not match the decrease of HSP60 content detected by 2-DE analysis. Real-time PCR showed that glutathione S-transferase P1 (GSTP1) and SOD1 mRNA expression was significantly decreased in liver of HC goats, while cytochrom c oxidase (COX3) and ATPase 8 (ATP8) mRNAs expression were markedly increased compared to LC (P < 0.05). Gene Ontology (GO) analysis revealed that HC diet resulted in altered expression of proteins related to catalytic and mitochondrial metabolism in the liver, and may increase the stress response with up-regulating the expression of differentiation 14 (CD14) cluster and serum amyloid A (SAA) as well as C-reactive protein (CRP) in the liver.ConclusionsThese results suggest that feeding high concentrate diet to lactating goats for 10 wk leads to the activation of the inflammatory response, and decreases the anti-oxidant capacity, and subsequently impairs the mitochondrial function in the liver.Electronic supplementary materialThe online version of this article (doi:10.1186/s40104-016-0065-0) contains supplementary material, which is available to authorized users.

Buffering Agent-Induced Lactose Content Increases via Growth Hormone-Mediated Activation of Gluconeogenesis in Lactating Goats

“…Other studies have shown that feeding lactating goats a diet containing 60 % concentrate led to elevated blood LPS concentrations (Dong et al 2013). The increased levels of circulating LPS also elevated the concentration of the pro-inflammatory cytokines IL-1β and TNF-α in the blood and increased activation of liver inflammatory responses (Duanmu et al 2016). The biochemical parameters ALT, AST and AKP in peripheral blood are common indicators that are used to assess the status of liver function (Sevinc et al 2001).…”

“…In addition, a decrease in rumen pH results in the release of lipopolysaccharides (LPS), which originate from the cell-wall component of Gram-negative bacteria (Li et al 2017). Previous studies have shown that LPS can translocate into the bloodstream from the digestive tract under high-permeability conditions after an injury to the liver tissue (Duanmu et al 2016).…”

Buffering Agent Induced Lactose Content Increases via Growth Hormone-Mediated Activation of Gluconeogenesis in Lactating Goats

“…Other studies showed that feeding a diet containing 60% concentrate to lactating goats elevated blood LPS concentrations[24]. The increased levels of circulating LPS also can elevated the concentration of blood pro-inflammatory cytokines IL-1β and TNF-α and activation of liver inflammatory responses [25,26]. The biochemical parameters ALT, AST and AKP in peripheral blood are common indicators used to assess the status of liver function 27 .…”

“…In addition, decreased rumen pH results in the release of lipopolysaccharide (LPS), which originate from the cell-wall component of gram-negative bacteria[5]. Previous studies have shown that LPS can translocate into the bloodstream from the digestive tract under conditions of high permeability, and after injury to the liver tissue [6].…”

Early solid diet supplementation influences proteomic of rumen epithelium in goat kids

“…In contrast, disease pathways were enriched by down-regulated proteins, which may imply that the intake of solid feed can improve the immune ability and disease resistance of the body. In fact, body's health influenced by diet has been reported in many studies [30][31][32]. Recently, researchers discovered that the timely introduction of solid foods for infants can effectively reduce the incidence of allergic diseases [33], which could be due to the characteristics of dietary metabolites that shape and improve the intestinal immune system of young animals [34].…”