Differentiation of Subclinical Ketosis and Liver Function Test Indices in Adipose Tissues Associated With Hyperketonemia in Postpartum Dairy Cattle.

Muhammad Ali Mohsin,Muhammad Bakhsh Abro,Przemysław Sobiech,Sarmad Sohaib,Rongze He,Peng Wang,Yulan Du,Chandra S Pareek,Huiru Yu,Klaudia Miętkiewska,Mariusz Pierzchala,Linli Gan,Bao Xiang He,Yunfei Huang

doi:10.3389/fvets.2021.796494

Abstract

Past studies suggested that during early lactation and the transition period, higher plasma growth hormone (GH) levels in subclinical ketosis (SCK) might involve the initiation of body adipose tissues mobilization, resulting in metabolic disorders in ruminants particularly hyperketonemia. The upregulated GH mRNA expression in adipose tissue may take part in the adipolysis process in SCK-affected cows that paves a way for study further. This study aimed to characterize the plasma levels of GH, β-hydroxybutyrate acid (BHBA) and non-esterified fatty acid (NEFA) and glucose (GLu) in ketotic cows and healthy control (CON) cows; to measure the liver function test (LFT) indices in ketotic and healthy CON cows, and finally the quantitative real-time PCR (qRT-PCR) assay of candidate genes expressed in adipose tissues of ketotic and healthy CON cows during 0 to 7 week postpartum. Three experiments were conducted. Experiment-1 involved 21 Holstein cows weighing 500–600 kg with 2–5 parities. Results showed that GH, BHBA, and NEFA levels in ketotic cows were significantly higher and the GLu level significantly lower. Pearson's correlation analysis revealed a significant positive correlation of GH with BHBA, NEFA, and GLu in ketotic and healthy CON cows. In experiment-2, dynamic monitoring of LFT indices namely, alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transpeptidase (GGT), total bilirubin (TBIL), direct bilirubin (DBIL), total protein (TP), albumin (ALB), globulin (GLOB) and albumin/globulin (A/G) were examined. The TBIL, DBIL, and GGT indices were significantly higher in ketotic cows and TP was significantly lower. In experiment-3, mRNA expression levels of GHR and peroxisome-proliferator-activated receptor alpha (PPARα) genes in adipose tissue were significantly upregulated in ketotic cows. However, the mRNA expression of insulin-like growth factor-I (IGF-1), insulin-like growth factor-I receptor (IGF-1R), and sterol regulatory element-binding protein-1c (SREBP-1c) genes in adipose tissue were downregulated in ketotic cows. Our study concluded that during postpartum, higher plasma GH levels in SCK cows might involve the initiation of body adipose tissue mobilization, resulting in hyperketonemia.

Highlights

Growth hormone (GH) is a naturally occurring peptide hormone produced by the pituitary gland that promotes growth and metabolism [1]
The results showed that GGT, total bilirubin (TBIL), and direct bilirubin (DBIL) were significantly higher in the ketotic cows than in healthy CON cows (p = 0.04, TABLE 4 | Correlation coefficient (r) analysis among plasma levels of GH, BHBA, non-esterified fatty acid (NEFA), and GLu in subclinical ketosis (SCK) and CON healthy dairy cows (n = 11) monitored weekly eight times during 0 to 7 weeks of postpartum
We found that the mRNA expression of Growth hormone receptors (GHRs) in adipose tissue was significantly higher and upregulated in hyperketonemia cows

Summary

Introduction

Growth hormone (GH) is a naturally occurring peptide hormone produced by the pituitary gland that promotes growth and metabolism [1]. During the early lactation period, dairy cows experience tremendous physiological and metabolic changes [8,9,10], accompanied by fetal development, milk production, high energy intake and a negative energy balance (NEB). Severe NEB initiates fat mobilization [13], metabolic stress [14, 15] and subsequently increases the blood concentrations of fatty acids and β-hydroxybutyrate (BHB), which can result in hyperketonemia development [16]. Some researchers have shown that downregulation of GHR in dairy cows elevated the GH level in the blood and reduced the different important factors, including IGF during the early lactation period [24, 25]. The negative balance of energy metabolism leads to excessive body fat mobilization, which triggers excessive production of ketone bodies in the liver resulting in an abnormal increase in blood levels. We designed the current study to determine the liver function test (LFT) indices, serum GH concentration levels and its dynamic variations in cows with postpartum SCK, and adipose tissue mRNA expression of the molecules related to the GH regulation pathway to reveal the mechanism of hyperketonemia in cows

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Results

Discussion

Conclusion