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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #104359

Title: EFFECT OF FEED RESTRICTION ON ADIPOCYTE TRANSCRIPT CONCENTRATIONS IN GENETICALLY LEAN AND OBESE PIGS

Author
item MCNEEL, RONALD - BAYLOR COLL. OF MEDICINE
item DING, SHIH-TORNG - BAYLOR COLL. OF MEDICINE
item SMITH, E - BAYLOR COLL. OF MEDICINE
item MERSMANN, HARRY

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/1999
Publication Date: 5/1/2000
Citation: N/A

Interpretive Summary: White adipose (fat) tissue, which stores energy, is controlled by genetic and environmental factors. The fat deposited represents a balance between energy intake and expenditure. We studied the fat tissue of genetically lean and obese pigs. We measured the genetic messages for several transcription factors (which are genetic regulators) and fat-characteristic cproteins in order to determine whether the genetic background influenced message concentrations. We also looked at these genetic messages (or transcript levels) during a 5-week period when we restricted the diet of the pigs, cutting it in half. Excess fat deposited in genetically obese pigs is associated with increased message concentrations for several proteins involved in fat synthesis and deposition. However, our findings showed that cutting the feed intake by half did not affect the message concentrations of these pigs. The pigs on restricted diets deposited less fat, but that was not regulated by the concentration of the genetic messages for several proteins that determine the growth of fat cells. That was surprising since we would have expected the decrease in fat tissue accretion to result in the adjustment of the genetic message concentrations. The findings suggest that the reduced fat deposition in pigs on restricted diets is not regulated by the message concentrations. The message concentrations are stable, suggesting adaptation to restricted feed intake is regulated at steps beyond the genetic message level.

Technical Abstract: Young, genetically obese and lean pigs were given ad libitum access to feed or were restrictively fed at 50% of ad libitum intake for 5 wk. Obese pigs were smaller and fatter than lean pigs, whether feeding was ad libitum or restrictive. Plasma protein, albumin, and cholesterol concentrations were greater in obese than lean pigs. Plasma NEFA, blood urea nitrogen, triglycerides, and postprandial glucose and insulin concentrations were less in pigs fed restrictively compared to pigs with ad libitum access to feed, regardless of genetic group. The adipose tissue glucose transporter 4, fatty acid synthase, and leptin transcript concentrations were greater in obese than lean pigs. The CCAAT/enhancer binding proteins beta and alpha, adipocyte fatty acid binding protein, hormone-sensitive lipase, and the beta1-adrenergic receptor transcript concentrations tended to be greater in adipose tissue than obese compared to lean pigs. Several other transcripts were numerically greater in obese than lean pigs. The data collectively suggest that messenger RNA concentration is a contributing factor to the excess fat deposition in these pigs. Restricted feeding did not change the concentration of any transcript except that for adipocyte fatty acid binding protein, which was reduced. The accretion of fat was markedly reduced in the restrictively fed pigs, but this diminution does not appear to be regulated by modulation of messenger RNA concentration.