Full text in pdf format

The effect of sex on the pattern of fat deposition in mice selected for body conformation

Laura Trumper; Ricardo J. Di Masso; Sandra Abdala; Maria Teresa Font

Departamento de Ciencias Fisiológicas, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, 20; Rosario, República Argentina

ABSTRACT

Patterns of fat deposition were studied in mice selected divergently at seven weeks for body conformation. This character was estimated by an index that combines body weight and tail length against the phenotypic correlation between them. The logarithmic form of the allometric equation was used to compare the patterns of fat deposition between lines in both sexes.
Selection did not alter the weight dependent pattern of fat deposition in males, while in females statistical differences were recorded for the allometric coefficients.
Differential exploitation of two recognized sources of genetic variation for body weight (appetite and efficiency of partitioning of metabolizable energy) are proposed for each sex. Selection apparently operates in males mainly on variation caused by differences in the rate of food consumption while in females it also exploits variation in the efficiency of conversion of energy to weight gain related to the amount of fat deposited.
The different pattern observed in males and females are related to fitness. Selection for low body weight near puberty would need a correlated response on fat deposition in females as it seems likely that a critical degree of fatness is necessary to allow the start of the reproductive cycles.

Keywords: Effect of sex; Fat deposition; Mice.

REFERENCES

Allen, P. and McCarthy, J.C. (1980). The effects of selection for high and low body weight on the proportion and distribution of fat in mice. Anim. Prod. 31: 1-11.

Bakker, H., Nagai, J. and Eisen, E.J. (1977). Genetic differences in age and weight at sexual maturation in female mice selected for rapid growth rate. J. Anim. Sci. 44: 203-211.

Bereskin, B. and Davey, R.J. (1976). Breed, line sex and diet effects and interactions in swine carcass traits. J. Anim. Sci. 42: 43-51.

Berg, R.T., Jones, S.D.M., Price, M.A., Fukuhara, R., Butterfield, R.M. and Hardin, R.T. (1979). Patterns of carcass fat deposition in heifers, steers and bulls. Canad. J. Anim. Sci. 59: 359366.

Di Masso, R.J., Abdala, S. and Font, M.T. (1988). Respuesta a la selección divergente for conformación corporal en el ratón. Mendeliana (in press).

Eisen, E.J. and Bandy, T. (1977). Correlated response in growth and body composition of replicated single trait and index selected lines of mice. Theor. Appl. Genet. 49: 133-144.

Eisen, E.J., Hayes, J.F., Allen, C.E., Bakker, H. and Nagai, J. (1978). Cellular characteristics of gonadal fat pads, livers and kidneys in two strains of mice selected for rapid growth. Growth 42: 7-25.

Falconer, D.S. (1984). Weight and age puberty in female and male mice of strains selected for large and small body size. Genet. Res. 44:47-72.

Folch, J., Lees, M. and Sloane-Standley, G.H. (1957). A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 226: 487-509.

Fowler, R.E. (1958). The growth and carcass composition of strains of mice selected for large and small body size. J. Agric. Sci. 51: 137-148.

Frisch, R.E. (1980). Pubertal adipose tissue: is it necessary for normal sexual maturation? Evidence from the rat and human female. Federation Proc. 39: 2395-2400.

Hayes, J.F. and McCarthy, J.C. (1976). The effects of selection at different ages for high and low body weight on the pattern of fat deposition in mice. Genet. Res. 27: 389-433.

Hetzel, D.J.S. and Nicholas, F.W. (1986). Growth, efficiency and body composition of mice selected for post-weaning weight gain on ad libitum or restricted feeding. Genet. Res. 48: 101-109.

Huxley, J.S. (1932). Problems of relative growth. Methuen &Co. Ltd., London.

Malik, R.C. (1984). Genetic and physiological aspects of growth, body composition and feed efficiency in mice: A Review. J. Anim. Sci. 58: 577-590.

McPhee, C.P. and Neill, A.R. (1976). Changes in body composition of mice selected for high and low eight week weight. Theor. Appl. Genet. 47: 21-26.

Mersmann, H.J. (1984). Effect of sex on lipogenic activity in swine adipose tissue. J. Anim. Sci. 58:600-604.

Roberts, R.C. (1979). Side effects of selection for growth in laboratory animals. Livestock Prod. Sci. 6:93-104.

Snedecor, G.W. and Cochran, W.G. (1967). Statistical Methods. Ames: Iowa State University Press.

Sutherland, T.M., Biondini, P.E., Haverland, L.H., Pettus, D. and Owen, W.B. (1970). Selection for rate of gain, appetite and efficiency of feed utilization in mice. J. Anim. Sci. 31: 1049-1057.

Sutherland, T.M., Biondini, P.E. and Ward, G.M. (1974). Selection for growth rate, feed efficiency and body composition in mice. Genetics 78: 525-540.

Timon, V.M. and Eisen, E.J. (1970). Comparisons of ad libitum and restricted feeding of mice selected and unselected for postweaning gain. I. Growth, feed consumption and feed efficiency. Genetics 64:41-57.

Van Der Spuy, Z.M. (1985). Nutrition and reproduction. Clin. Obstet. Gynaecol. 12:579-599.