Serum leptin concentration in pigs selected for high or low daily food intake

Selection for high or low daily food intake (DFI) in Large White pigs resul ted in higher serum leptin concentration, fat deposition and food intake in the high DFI line. The response in serum leptin concentration indicated th at the higher fat deposition of the high DFI line was not due to insufficie nt leptin production, as in the Lep(ob)/Lep(ob) mouse. Serum leptin was mor e highly correlated with fat deposition than with food intake indicating th at the response in serum leptin was primarily due to increased fat depositi on rather than to higher energy intake per se. The low correlations between serum leptin measured at 30 kg and performance test traits indicate that s erum leptin would not be efficient for selection of animals prior to perfor mance test. However, the consistent positive correlations between serum lep tin and a measure of fat deposition suggest that serum leptin could usefull y be incorporated in selection criteria for genetic improvement of carcass lean content in pigs.