Evaluating Oxidative Stress Parameters, Pepsinogen, and Insulin-like Growth Factor-1 in Dairy Cows with Displacement of Abomasum

Introduction: Displacement of the abomasum (DA) frequently occurs in highproducing dairy cows. It is a multifactorial disease and has an economic impact on dairy farms. This study aimed to investigate the levels of pepsinogen, Insulin-Like Growth Factor-1, and oxidative stress parameters (malondialdehyde and nitric oxide) in DA cases. Materials and methods: Blood samples were taken from 51 dairy cows suspected of DA, referring to the Veterinary Clinic of Shiraz University, Shiraz, Iran, in the summer of 2021. Twenty of them had Left DA (LDA), 6 had Right DA (RDA), 13 had LDA with clinical signs of ulcer of the abomasum, 3 had RDA with clinical signs of ulcer of the abomasum, and 9 of them (3-5 years old) were clinically healthy as control. The serum concentration of pepsinogen, Insulin-Like Growth Factor-1, malondialdehyde, and nitric oxide were measured. Results: The result of the current study showed that the concentration of pepsinogen was higher in cows with DA compared to healthy cows. The concentrations of malonaldehyde, nitric oxide, and IGF-1 were higher in LDA with the abomasal ulcer, compared to other groups. Conclusion: Pepsinogen can be suggested as a predictor parameter for DA. Malonaldehyde, nitric oxide, and IGF-1 can be considered biomarkers in LDA with the abomasal ulcer. However, further studies are needed to find other effective parameters for predicting DA. Keywords: Abomasal ulcer Displacement High-producing Malondialdehyde Nitric oxide

Introduction

Displacement of the abomasum (DA) can be frequently observed in high-producing dairy cows. It is a multifactorial disease and has a negative economic impact on dairy farms, mostly 3-4 weeks after parturition1. The etiology of DA has not clearly been understood; however, some diseases, such as fatty liver, ketosis, and hypocalcemia, are associated with DA2,3. Reduction in dry matter intake in the transitional period in dairy cows is one of the contributing factors to DA4. Moreover, diseases, such as rumen atony and decreased rumen contraction, hypocalcemia, endotoxemia, alkalemia, and hyperinsulinemia, might be predisposing factors for DA5. Displacement of the abomasum is characterized by the accumulation of gas in the abomasum and displacement of the abomasum to the dorsal part of the abdomen. The hypothetical cause of gas accumulation in the abomasum is an increase in gas production in the abomasum and a hypomotility of the abomasum1. Clinical signs of DA are colic, anorexia, milk yield drop, cow discomfort, and death in some cases4. The growth hormone axis is an important endocrine control center that plays a vital role in metabolic adaptation in dairy cows6. According to some studies, Insulin-Like Growth Factor-1 (IGF1) may be useful as a predictive marker for postpartum production diseases3,6. Some researchers reported that oxidative stress parameters, such as malondialdehyde and nitric oxide, can be used to evaluate inflammatory conditions, ischemic effects, and tissue damage caused by obstruction, strangulation, or both in gastrointestinal disorders7-9. Pepsinogen levels in the blood could be a useful means of diagnosing DA in cattle10. Pepsinogen is a proenzyme produced by parietal cells of the abomasal mucosa. In humans, serum pepsinogen is elevated in different diseases, including gastric and duodenal ulcers11. Therefore, the current study aimed to investigate the levels of pepsinogen, InsulinLike Growth Factor-1, and oxidative stress parameters (malondialdehyde and nitric oxide) in referral DA cases.