Periodic 48 h feed withdrawal improves glucose tolerance in growing pigs by enhancing adipogenesis and lipogenesis

Abstract

BackgroundAdipocyte numbers and peroxisome proliferators activated receptorγ (PPARγ) expression of retroperitoneal tissue increased while area under the curve (AUC) during the glucose tolerance test (GTT) was reduced in rats subjected to certain feed withdrawal (FW) regimens. Thus, using pigs as the experimental model, the hypothesis that FW regimens influence glucose tolerance by influencing fat cell function was evaluated with the objective of determining the effect of a single (FWx1; at age of 19 wk for 48 h) or periodic, multiple (FWx4; 24 h FW at 7 and 11 wk of age and 48 h FW at 15 and 19 wk of age) FW on AUC of glucose and insulin during the GTT relative to pigs that did not experience FW (Control).MethodsGrowth, body composition, adipocyte numbers, PPARγ expression, lipogenic potential as glucose uptake into fat of adipocytes of varying diameter in omental (OM) and subcutaneous (SQ) fat as affected by FW regimens were determined in pigs initiated into the study at 5 wk of age and fed the same diet, ad libitum.ResultsBlood glucose concentrations for prior to and 120 min post glucose meal tended to be lower (p = 0.105 and 0.097, respectively) in pigs in FW treatments. In OM fat; cell numbers, glucose Universal14C [U14C] incorporation into fat and rate of incorporation per 104 cells was greatest for cells with diameters of 90-119 μm. Pigs undergoing FWx4 tended to have greater (p = 0.0685; by 191%) number of adipocytes, increased (p = 0.0234) glucose U14C incorporation into adipocytes and greater (p = 0.0872) rate of glucose uptake into cells of 119-150 μm diameter than of cells from control or FWx1 pigs. Subcutaneous adipocyte numbers in 22-60 and 61-90 μm diameter ranges from pigs in FWx1 tended to be greater (p = 0.08 and 0.06, respectively) than for those in FWx4 treatment, yet PPARγ expression and total cell number were not affected by treatment.ConclusionsResults suggest that FW regimens influence fat cell function or lipogenesis rather than number, affecting glucose metabolism and may have implications in drug-free control of metabolic syndrome symptoms.

Preadipocyte and Adipose Tissue Differentiation in Meat Animals: Influence of Species and Anatomical Location

“…Moreover, brown, white, and beige adipocytes may be detected in transiting populations throughout development (29). Although a variety of in vivo physiology/treatments may alter adipocyte characteristics in the live animal (84)(85)(86)(87)(88)(89)(90)(91), the cellular compositions of specific adipose depots are likely carried forward when isolating cells for subsequent use in vitro (5,92,93). As such, it is quite difficult to isolate consistent numbers of similar cells from adipose depots, both within and between animals (2,6,92,94,95).…”