Longitudinal Profiling of the Tissue-Specific Expression of Genes Related with Insulin Sensitivity in Dairy Cows during Lactation Focusing on Different Fat Depots

Abstract

In dairy cows the milk associated energy output in early lactation exceeds the input via voluntary feed intake. To spare glucose for mammary lactose synthesis, peripheral insulin sensitivity (IS) is reduced and fat mobilization is stimulated. For these processes a link between IS and the endocrine functions of adipose tissue (AT) is likely; we thus aimed to characterise the mRNA expression from bovine AT derived proteins and receptors that are related to IS according to the literature in metabolically active tissues plus systemic IS throughout lactation. Conjugated linoleic acids (CLA) reduce milk fat thus decreasing the milk drain of energy and potentially dampening lipolysis, but may also affect IS. Subcutaneous (s.c.) AT and liver from pluriparous cows receiving either control fat or CLA supplement (100 g/day from 1 to 182 days in milk each) were biopsied covering week −3 to 36 relative to parturition. In an additional trial with primiparous cows treated analogously and slaughtered on days in milk 1, 42 or 105, samples from liver, udder, skeletal muscle and 3 visceral and 3 s.c. AT were obtained and assayed for mRNA abundance of adiponectin, its receptors, leptin, leptin receptor, PPARγ, PPARγ2, IL-6, and TNF-α. In pluriparous animals, the mRNA abundance of most of the target genes decreased after parturition in s.c. AT but increased in liver. In primiparous cows, AT depot specific differences were mostly related to retroperitoneal AT; adiponectin receptor 1 and TNF-α were affected predominantly. CLA effects in primiparous cows were largely limited to decreased PPARγ2 mRNA abundance in udder tissue. In pluriparous cows, insulin secretion was increased by CLA resulting in decreased systemic IS but without consistent changes in tissue target mRNA abundance. The temporal gene expression profiles from the adipokines and related receptors support their coactive function in adapting to the needs of lactation.

Effect of prepartal ad libitum feeding of grass silage on transcriptional adaptations of the liver and subcutaneous adipose tissue in dairy cows during the periparturient period

“…The lack of changes in the expression of ADIPOQ and its receptors from pregnancy to early lactation was consistent with previous studies (Giesy et al, 2012;Selim et al, 2014). Conversely, Ji et al (2012), Khan et al (2013), and Saremi et al (2014) reported that the expression of ADIPOQ gradually decreased during the peripartal period. However, Giesy et al (2012) reported that plasma ADIPOQ concentrations may decrease during early lactation independently of ADIPOQ expression in SAT, and indicated that the formation of circulating ADIPOQ complexes may be a major determinant of the plasma concentrations of this adipokine.…”

“…The decline of LEP during the transition period concurred with previous studies showing a decrease of plasma LEP concentration (Block et al, 2001;Kokkonen et al, 2005) or LEP expression (Saremi et al, 2014;Selim et al, 2014). The downregulation of LEP postpartum in both groups and particularly in the HE group may support the concomitant retrieval of DMI and energy balance (Roche et al, 2013).…”

“…The downregulation of PPARA at d 7 compared with d 1 postpartum was in line with the declining trend of blood NEFA concentration during the first lactation week, and could explain the lack of time effect in its target genes (CPT1A, SLC22A5, and PC) around calving. The downregulation of hepatic PPARG early postpartum in the current study was in agreement with Saremi et al (2014). Although the expression of PPARG is low in ruminant liver , it has been suggested that reduced hepatic expression of PPARG might be linked to enhanced gluconeogenic capacity or reduced FA infiltration of the liver (Saremi et al 2014).…”

“…The downregulation of hepatic PPARG early postpartum in the current study was in agreement with Saremi et al (2014). Although the expression of PPARG is low in ruminant liver , it has been suggested that reduced hepatic expression of PPARG might be linked to enhanced gluconeogenic capacity or reduced FA infiltration of the liver (Saremi et al 2014). …”

Expression of NGF, BDNF and their receptors in subcutaneous adipose tissue of lactating cows

“…To date, no measurements of neurotrophic factors and their receptor in adipose tissues of cattle have been reported, but it is well known that fat depot mass and biological activity changes dramatically during the lactation cycle in dairy cows (Saremi et al, 2014). Similarly, a large body of research has been devoted to the study of fat metabolism and its implication on physiological regulation during health and disease conditions in dairy cows (McNamara and Hillers, 1986;Graugnard et al, 2012 andSgorlon et al, 2015).…”