Effectiveness of divergent selection for open-field activity in rabbits and correlated response for body weight and fertility.
Two lines deriving from the same rabbit stock were selected for 8 generations for high (H) or low (L) locomotor activity score in the open field (OFS). The divergent selection was most effective up to the 3rd generation in the H line and up to the 4th generation in the L line. In further generations a decrease of OFS in the H line and a "floor effect" (OFS = 0) in the L line were observed. The mean OFS increased significantly in consecutive trials in the H line, whereas this increase was non-significant in the L line. There was a negative and very high correlation between the latency to enter the open field and the OFS (-0.95 and -0.98 for the H and L line, respectively). The realized heritability of the OFS was 0.46 and 0.23 in generations 0-3 within the L and H line, respectively, and 0.44 and -0.06 in generations 0-8. As calculated on the basis of divergent selection, the heritability was 0.31 and 0.15 for generations 0-3 and 0-8, respectively. The L rabbits were heavier shortly before (4th wk, P < 0.001) and after (8th wk, P < 0.01) weaning, than those of the H line, whereas the H rabbits grew faster (P < 0.05) between the 4th and 20th wk of age. There was a tendency for decreasing weight gains in consecutive generations. Generally, a lower percentage of H females delivered litters than those of the L line, but this was due to a very low percentage of such females in the 3rd and 6th generations. It can be assumed that H and L lines represent different, i.e., active and passive, coping strategies. These lines of rabbits offer increased possibilities for physiologically and ethologically oriented studies, e.g., on the welfare of caged animals.
Daniewski
Wojciech
W
Polish Academy of Sciences, Institute of Genetics and Animal Breeding, Jastrzebiec, 05-552 Wó1ka Kosowska, Poland.
Jezierski
Tadeusz
T
D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000235:genetics / Q000502:physiology*; D005260:Female; D005298:Fertility / Q000235:genetics* / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000235:genetics* / Q000502:physiology*; D011817:Rabbits