Effect of prepartum supplementation with niacin, choline and cod liver oil on postpartum insulin sensitivity and the redox status in cows with subclinical ketosis

Abstract

There have been limited field trials exploring the potential ameliorative effect of B-complex vitamin or antioxidant therapy in cows with prolonged insulin resistance (IR). The purpose of this study was to explore the effect of prepartum supplementation of niacin, choline and cod liver oil on metabolic status, indices of insulin sensitivity (IS) as well as markers of oxidative stress in cows with subclinical ketosis (SCK). For this purpose, 24 apparently healthy cows at ~3 weeks before the expected time of calving were studied. Based on their serum concentration of non-esterified fatty acid (NEFA) and β-hydroxybutyrate (BHBA), the studied cows were classified as having SCK (n = 20) or normal (n = 4). The diseased cows were then randomly allocated into four equal-sized groups and received the following feed supplements for subsequent 6 weeks: rumen-protected niacin, (RPN – group; n = 5); rumen-protected choline (RPC – group; n = 5); and cod liver oil (CLO-group; n = 5); or remained without treatment (SCK – group; n = 5). Serum samples were collected from all animals (n = 24) in two occasions i.e. before and after treatment to quantify concentrations of BHBA, NEFA, glucose, insulin, cortisol, and triglyceride, malondialdehyde and superoxide dismutase. Indices of IS were also calculated. The findings of this study suggest benefits of prepartum supplementation to cattle with SCK, particularly RPC which demonstrated great effect on BHBA, triglyceride, and very low-density lipoprotein; but it showed a minimal effect on IS. On the other side, RPN and CLO exhibited a marked effect on serum cortisol and potentiated IS with minimal effect on BHBA. All dietary supplements had nearly equal effect on NEFA, glucose, insulin, and markers of oxidative stress. The information provided in this study could support the advancement of the future investigations in animal welfare and production.