Feed restriction alters lipogenic and adipokine gene expression in visceral and subcutaneous fat depots in lamb

Abstract

Currently, lipogenic and adipokine gene expression patterns in different fat depots during long-term feed restriction in growing lambs are poorly understood. This study aimed to determine the effects of long-term nutritional deficiency on lipogenic and adipokine gene expression in subcutaneous and visceral fat depots in lambs. Twenty male lambs (4 months old; 21.81±0.75kg body weight) were randomly assigned to either control or feed-restricted groups. After 60 days of maintenance-level feed restriction, femoral, omental, mesenteric, epicardial, and perirenal fat were collected. Gene expressions were estimated by quantitative real-time PCR, and plasma parameters were also determined. The results showed that feed restriction increased the plasma concentration of NEFA (P<0.05) at 30 days, and decreased the plasma concentration of triglycerides, glucose, and insulin (P<0.05) at 30 days and 60 days. Feed restriction decreased lipogenic gene expression (acetyl coenzyme A carboxylase alpha and fatty acid synthase) in all five fat depots. The related key regulating gene PPARγ mRNA decreased (P<0.05) in femoral, omental, and mesenteric fat depots, while sterol regulatory element binding transcription factor 1 decreased (P<0.05) in femoral fat depots. Perilipin, as a barrier to lipolysis, decreased (P<0.05) in femoral, omental and perirenal fat depots of the feed restriction group. Adipose tissue-derived hormone leptin mRNA decreased (P<0.05) in all five fat depots, while adiponectin decreased (P<0.05) only in omental, mesenteric, and epicardial depots. Macrophage marker CD68 mRNA increased (P<0.05) in femoral and mesenteric fat depots. In addition, tumor necrosis factor-α mRNA increased in femoral, omental, and mesenteric depots, whereas IL-1β mRNA increased in femoral and perirenal depots. IL-6 expression decreased in femoral, omental, and epicardial fat depot at the end of feed restriction. Nutritional deficiency induced different changes in lipogenic and adipokine gene expression between visceral and subcutaneous adipose tissue. The decreased leptin, adiponectin, and increased inflammatory factors may inhibit lipogenesis and stimulate lipolysis to protect the body against the threat of starvation.