SELECTION EXPERIMENT IN PIGS TO IMPROVE C ARCASS TRAITS BY USING BIOCHEMICAL TRAITS OR ULTRASONIC MEASUREMENTS - 2ND COMMUNICATION - COMPARISON OF THE SELECTION LINES IN THE LAST GENERATION

In a selection experiment with pigs the effect of selection for NADPH- generating enzymes in opposite directions was investigated concerning the change of meat and fat content. After 9 generations the effectivit y of selection was analysed. By means of a control line the symmetry o f selection for enzyme activity could be calculated. A further line wa s selected for low backfat thickness with ultrasonic measurements on l ife animals. The main results can be summerized as follows: - Selectio n for activity of NADPH generating enzymes in opposite directions resu lts in a significant differentiation of the selection lines in enzyme activity. - A comparison of the results in the enzyme lines with the r esults in a control line give no hints for asymmetrical selection resp onse for the NADPH-generating enzymes. - Selection for enzyme activity leads also to a significant correlated selection response on carcass composition. - The correlated selection response on carcass traits was asymmetrical. The correlated selection response by selecting for low enzyme activity was significantly higher compared with selection for h igh enzyme activity. - Selection for enzyme activity has no significan t selection response on traits for meat quality and stress resistance. The pigs of the control line had the best meat quality and the highes t stress resistance. - The animals of the low enzyme line had a reduce d feed intake and a reduced daily gain, compared with the animals of t he other lines. - In the reproduction traits there were no differences between the enzyme lines. - In tendency selection for low backfat thi ckness was more effective than selection for low enzyme activity, espe cially for traits of carcass composition.