Prepartal high-energy feeding with grass silage-based diets does not disturb the hepatic adaptation of dairy cows during the periparturient period

Abstract

The liver of dairy cow naturally undergoes metabolic adaptation during the periparturient period in response to the increasing demand for nutrients. The hepatic adaptation is affected by prepartal energy intake level and is potentially associated with inflammatory responses. To study the changes in the liver function during the periparturient period, 16 cows (body condition score = 3.7 ± 0.3, mean ± standard deviation; parity = second through fourth) were allocated to a grass silage-based controlled-energy diet (104 MJ/d) or a high-energy diet (135 MJ/d) during the last 6 wk before the predicted parturition. Liver samples were collected by biopsy at 8 d before the predicted parturition (-8 d) and at 1 and 9 d after the actual parturition (1 and 9 d). The lipidomic profile of liver samples collected at -8 and 9 d was analyzed using ultra performance liquid chromatography-mass spectrometry-based lipidomics. Liver samples from all the time points were subjected to microarray analysis and the subsequent pathway analysis with Ingenuity Pathway Analysis software (Ingenuity Systems, Mountain View, CA). Prepartal energy intake level affected hepatic gene expression and lipidomic profiles prepartum, whereas little or no effect was observed postpartum. At -8 d, hepatic lipogenesis was promoted by prepartal high-energy feeding through the activation of X receptor/retinoid X receptor pathway and through increased transcription of thyroid hormone-responsive (THRSP). Hepatic inflammatory and acute phase responses at -8 d were suppressed (z-score = -2.236) by prepartal high-energy feeding through the increase in the mRNA abundance of suppressor of cytokine signaling 3 (SOCS3) and the decrease in the mRNA abundance of interleukin 1 (IL1), nuclear factor kappa B 1 (NFKB1), apolipoprotein A1 (APOA1), serum amyloid A3 (SAA3), haptoglobin (HP), lipopolysaccharide-binding protein (LBP), and inter-α-trypsin inhibitor heavy chain 3 (ITIH3). Moreover, prepartal high-energy feeding elevated hepatic concentrations of C18- (7%), C20- (17%), C21- (26%), C23-sphingomyelins (26%), and total saturated sphingomyelin (21%). In addition, cows in both groups displayed increased lipogenesis at the gene expression level after parturition and alterations in the concentration of various sphingolipids between the first and last samplings. In conclusion, prepartal high-energy feeding promoted lipogenesis and suppressed inflammatory and acute phase responses in the liver before parturition, whereas only minor effects were observed after parturition.

Keywords: dairy cow; lipidomic profiling; microarray; periparturient period; physiological adaptation.