Changes in the levels of acute-phase protein and other serum protein fractions in Santa Inês ewes fed with a high-concentrate diet

Abstract

The aim of this study was to evaluate the effects of subacute ruminal acidosis (SARA) on total serum protein (TP), plasma fibrinogen (Fb), and serum protein fractions in seven hay-adapted Santa Inês ewes fed with a highconcentrate diet for 133 days. Blood was extracted, before feeding, by external jugular venipuncture into tubes with ethylenediaminetetraacetic acid dipotassium anticoagulant, to evaluate the Fb concentration by heat precipitation, and into plain tubes, for TP analysis by the Biuret method and for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). SDS-PAGE obtained the following proteins: immunoglobulin A (IgA) and G (IgG); ceruloplasmin (Cp); transferrin (Tf); albumin; α 1 -antitrypsin (α 1 AT); haptoglobin (Hp); α 1 -acid glycoprotein (α 1 AG); and 140, 101, 95, 46, 36, 34, 31, and 23 kDa molecular weight proteins (MWP). Associations among variables and time were evaluated using regression analysis. Fb concentrations did not change (P > 0.05); IgA, α 1 AT, and Hp levels increased, while Cp decreased throughout the period. Mean Tf levels increased, reaching the highest value on the 72nd day. The other protein levels oscillated during the study. A positive correlation, measured using Pearson's coefficient, was found between TP and IgG levels (r = 0.77; P < 0.0001). IgA, Hp, Tf, and α1AT showed greater potential for use in the diagnosis of SARA. The occurrence of proteins with unknown functions, but that have been highly influenced by the high-grain diet, increases the possibility of identifying inflammatory markers for SARA.

Ameliorative effects of supranutritional selenium on TLR‐4‐NF‐kB‐TNF‐α‐mediated hepatic oxidative injury and inflammation in goats fed high concentrate diet

“…Besides, Li et al ( 2019 ) observed hepatic Hp upregulation in the newborn calves induced with subacute ruminal acidosis (SARA) through starch‐rich diet for 16 weeks, while Hp expression was not affected in adult dairy cows fed HC diet for 8 weeks (Guo et al, 2017 ). The upregulation of Hp is linked with ruminal acidosis, damaged GIT wall and elevated blood LPS levels thus the overexpression of Hp has been considered as potential marker of severe ruminal acidosis in ruminants (Girardi et al, 2018 ). Hence, lack of effect of HC diet on Hp expression suggests gradual adaptation to concentrated diet over a period (Chishti et al, 2020 ).…”

“…Plasma AGP level initially decreased and then subsequently increased in sheep fed HC diet (Girardi et al, 2018 ) and the LPS challenge increased hepatic AGP expression in cow (Jiang et al, 2008 ). Though the role of AGP is not fully understood but several studies have shown its protective effects against inflammation and thus considered as powerful anti‐inflammatory agent (Brown et al, 2021 ).…”

“…In current study, the increased hepatic mRNA expressions of AGP, TLR‐4 accompanied by upregulation of anti‐inflammatory cytokine IL‐10 in HC goats suggest the anti‐inflammatory effects of AGP. Albumins represent 40–60% of total proteins in circulation and the decreased albumin concentrations is a consequence of reduced synthesis which may be due to increased utilization of amino acids for the synthesis of cytokines and APPs (Girardi et al, 2018 ; Tothova et al, 2014 ). In accordance with our findings, feeding HC diet downregulated ALB gene expression in sheep (Chishti et al, 2020 ).…”