Correlated responses in development and distribution of fat depots in mice selected for body composition traits

Abstract

Development of adipose tissue in five depots was investigated in mice selected for high or low 12-week epididymal fat pad weight as a percentage of body weight (HF and LF lines), or high or low 12-week hind carcass weight as a percentage of body weight (HL and LL lines). An unselected control line (RC) was maintained. Hind carcass (HC) and fat pads from subcutaneous hindlimb, subcutaneous forelimb, gonads, kidneys and mesentery were dissected and weighed at 4, 6, 9, 12 or 15 weeks of age. Generally, body weight (BW), daily gain (DG), feed intake (FI), feed efficiency (FE) and feed intake/metabolic body weight (FC) were higher (P≤0.05) in HF than in LF, and in LL than in HL. HF had more fat (as a percentage of BW) than LF in all depots (P≲-0.01), and asymmetry (P≤0.01) was detected for gonadal fat. LL consistently had a higher (P≤0.01) fat percentage than HL, and asymmetry (P≤0.01) was observed for perirenal fat. At age of selection, ranking of fat depot weights as a percentage of total fat depot weight was not changed by selection; however, gonadal fat accounted for more of the total fat in HF and LL compared with RC, while the opposite was found in LF and HL. HC percentage was higher (P≤0.01) in HL than LL, and higher (P≤0.01) in LF than HF. Growth rate of each fat depot relative to BW was not affected by selection. These results demonstrated that selection for proportion of fat in one depot or for HC percentage changed fat percentage in other depots. However, the rate of fat deposition in each depot relative to body weight gain was not altered.

Analysis of lines of mice selected on fat content: 4. Correlated responses in growth and reproduction

“…The relative growth of the three fat deposits appeared unchanged, an interesting result as the lines were selected on the ratio of gonadal fatpad to body weight during the first 20 generations of selection and analysis of the original lines at generations 20 and 29 had suggested the proportion of total fat contained within the gonadal fatpad had been altered (Hastings, 1989;Hastings & Hill, 1989). A subsequent investigation into the growth of fat deposits in these lines (Prasetyo & Eisen, 1989) showed that fat deposition in the lean lines ceased around 9 weeks of age, similar to our Lean Line (Figs. 2) suggesting their growth was regulated by the same set of genes, distinct from those which regulate growth in other sites such as subcutaneous deposits.…”

Lack of Socs2 expression reduces lifespan in high-growth mice

“…As the number of parturitions increased, the survival probability of females had a suggested increase. The relation between aging and obesity is well established (Barzilai and Gupta 1999) and the differential fat deposition between male and females (Prasetyo and Elsen 1989) could account for survival differences shown in Table 2, although further studies are required to confirm this hypothesis.…”

Multitrait restricted and desired gains selection indices designed to change growth and body composition in mice1

“…Realized genetic correlations between EF/BW and fat content in the hind carcass and between EF/BW and SF/BW were high (E isen 1987a). Further, P rasetyo and E isen (1989) reported high positive correlated responses in other fat depots, including ages other than 12 weeks, the age of high‐low selection for EF/BW (E isen , 1987b). However, selection for EF/BW led to a change in the ratio of EF to total fat in two studies (H astings and H ill 1989; E isen and C offey 1990), suggesting that local control of fat metabolism exists at different sites of fat deposition.…”