Meeting Abstract
12.8 Monday, Jan. 4 Basal Metabolic Rate (BMR) of parents is positively correlated with postnatal growth rate of offspring in laboratory mice GEBCZYNSKI, AK*; SADOWSKA, J; KONARZEWSKI, M; Univ. of Bialystok, Poland; Univ. of Bialystok, Poland; Univ. of Bialystok, Poland andgebcz@uwb.edu.pl
One of the postulated evolutionary advantages of high basal metabolic rate (BMR) is its positive association with the rate of reproduction, which includes positive association with high individual growth rate. The latter may stem from (1) more effective parental care of parents characterized by high BMR, (2) higher growth rate of offspring having high BMR or (3) both. To test (1-3) we compared growth rates of mice from two lines divergently selected for high (H-BMR) and low (L-BMR) BMR. This long-term selection resulted in over 30% between-line difference in mass-corrected BMR and related traits, such as the mass of internal organs associated with energy assimilation rate. To discriminate between the effect of line-specific growth rate and parental care we swapped pups between litters and lines, thus creating 86 litters of 8 pups (each of 4 pups from L-BMR and H-BMR line) nourished by 44 and 42 mothers from H-BMR and L-BMR line, respectively. When litters were nourished at ambient temperature of 23°C, there was no effect of mother’s line affiliation on growth rate of foster offspring. However, independent of the line affiliation of the foster mother, pups from H-BMR line grew faster than those from L-BMR line, which supports (2). It is also possible, that the advantages of high BMR of parents becomes apparent only under metabolically stressful conditions. To test this, we repeated the above described experiment on another batch of 30 litters exposed to an ambient temperature of 17°C. Independent of the line of origin, pups nourished by L-BMR mothers grew slower than their counterparts. Still however, growth rate of pups of H-BMR line was higher than that of L-BMR line. Taken together our results showed that high BMR is positively associated with both the quality of parental care and the rate of individual growth
