Temporal patterns of liver and adipose lipase abundance across the periparturient period in multiparous Holstein dairy cows

Lipases such as patatin-like phospholipase domain-containing protein 3 (PNPLA3) exist in multiple tissue types. In subcutaneous adipose tissue, PNPLA3 was not altered during the periparturient period. Conversely, strong associations between liver PNPLA3 and liver triglyceride content peripartum were identified and confirmed to be causative using knockdown approaches in a primary bovine hepatocyte model. The objective of this research was to characterize adipose and hepatic lipase abundance, as well as abundance of hepatic transcription factors (TF) involved in adipose and liver tissue lipolysis to determine potential impact on bovine fatty liver development and recovery. Adipose and liver tissue biopsy samples were collected from -28 to +56 d relative to calving (DRTC) from multiparous Holstein dairy cows randomly assigned to either a control (CTL) or ketosis induction protocol (KIP) diet. Clinical ketosis (blood BHB ≥ 3.0 m<i>M</i>) was used as a cowside indicator of successful induction and was achieved in CTL (n = 2) and KIP (n = 12) cows. Both adipose and liver abhydrolase domain-containing protein 5 and adipose triglyceride lipase (ATGL) differed across DRTC, as did liver perilipin 1. Hepatic mature and immature carbohydrate response element binding protein, and sterol regulatory binding protein 1c, varied or tended to vary across DRTC × treatment. Neither adipose nor liver hormone sensitive lipase (HSL) were responsive to treatment or varied across DRTC, but adipose HSL was positively associated with nonesterified fatty acids at +1 DRTC. Adipose and liver ATGL was associated with liver triglycerides across all DRTC. Patterns of adipose HSL and ATGL abundance did not explain the increase in nonesterified fatty acids observed at +1 DRTC in this study. Future investigation of lipase abundance in other adipose tissue depots is still needed to better explain regulation during this time. Bovine fatty liver development and recovery appears to be contingent upon liver PNPLA3 abundance, rather than liver ATGL.