Dietary l-carnitine Supplementation Modifies the Lipopolysaccharide-Induced Acute Phase Reaction in Dairy Cows

Abstract

l-carnitine plays an important role in energy metabolism through supporting the transport of activated fatty acids to the subcellular site of β-oxidation. An acute phase reaction (APR) is known as an energy consuming process. Lipopolysaccharides (LPS) are often used in animal models to study intervention measures during innate immune responses such as APR. Thus, the aim of the study was to investigate the effects of dietary l-carnitine supplementation during an LPS-induced APR in mid-lactating German Holstein cows. Animals were assigned to a control (CON, n = 26) or l-carnitine group (CAR, n = 27, 25 g rumen-protected l-carnitine/cow/d) and received an intravenous injection of LPS (0.5 μg/kg body weight) at day 111 post-partum. Blood samples were collected from day 1 pre-injection until day 14 post-injection (pi). From 0.5 h pi until 72 h pi blood samplings and clinical examinations were performed in short intervals. Clinical signs of the APR were not altered in group CAR except rumen motility which increased at a lower level compared to the CON group after a period of atonia. Group CAR maintained a higher insulin level compared to group CON even up to 72 h pi which might support glucose utilization following an APR.

Microbiome Clusters Disclose Physiologic Variances in Dairy Cows Challenged by Calving and Lipopolysaccharides

“…Blood samples were collected at 37 time points, and 23 time points were included in the present study, covering 62 metabolites and cellular parameters (see Data Set S8 at https://github.com/SebasSaenz/Troscher-Mussotter_Cow-enterotypes_2021/tree/main/Datatsets ). The effects of time point and treatment on red blood cell count ( 15 ), energy metabolism, and electrolytes ( 16 , 17 ) have recently been published. Among all the parameters, chloride (Cl) is significantly different ( P < 0.0001) between each microbiome cluster, with the highest significance in C-Bifi and the lowest in C-Spiro ( Fig.…”

“…However, CAR animals had higher milk fat and serum triacylglyceride concentrations ( 16 ), as well as increased blood platelets and plateletcrit ( 15 ) during early lactation. In addition, higher insulin levels and lower NEFA concentrations were observed after LPS injection ( 17 ).…”

“…This study is part of the cooperative project “Mitochondrial functionality in dairy cows” (MitoCow) funded by the German Research Foundation (DFG), including 54 multiparous Holstein Frisian dairy cows ranging between 3 and 7 years of age and grouped into a control (CON; n = 30) and a carnitine-supplemented (CAR; n = 24) herd. Detailed dietary and nutritional composition and study approaches for the calving period are described by Meyer et al ( 16 ) and for the LPS challenge by Meyer et al ( 17 ). In short, 80% roughage and 20% of concentrate were fed until calving (day 0) and contained the supplements in the concentrate feed.…”

“…A total of 626 fecal samples were stored at −80°C, and not all samples were included in all analysis. Blood was collected from the external jugular vein by needle puncture or by indwelling catheters for the frequent sampling during the challenges as described by Meyer et al ( 17 ).…”

“…Blood metabolites (nonesterified fatty acids, triglycerides, glucose, beta-hydroxybutyrate) were determined in serum samples by using an automatic clinical chemistry analyzer (Eurolyser CCA 180; Eurolyser Diagnostica GmbH, Salzburg, Austria) ( 15 ). Residual energy intake (REI), milk parameters, body weights, and daily visual health examinations by the same veterinarian were recorded and recently published ( 16 , 17 ). The average number of sick days per sick cow was calculated, ignoring the quantity of multiple health issues at 1 day per individual.…”