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C57BL/6NHsd male mice started on high‐fat diets at three, six, or nine weeks of age attain similar obesity phenotypes
Author(s) -
Flowers Jessica,
Mickelson Barbara
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.554.6
Subject(s) - obesity , medicine , endocrinology , body weight , zoology , biology
The C57BL/6 mouse strain fed a high‐fat diet (HFD) with ~60% of kcals from fat (lard) is an established rodent model of diet‐induced obesity. To determine if there is an ideal start age or diet composition which enhances development of obesity phenotypes, two HFD patterns were initiated at 3, 6, or 9 weeks of age. The HFD varied in fat (F, amount and type) and sucrose (S), abbreviated as follows in percent energy: 45F30S (milkfat) and 60F10S (lard). The HFD fed mice were compared to mice fed a purified low‐fat control (17F7S). Body weight and food disappearance were assessed once weekly in the nine groups of mice (n=15–16/group). Half of the mice underwent a glucose tolerance test at 17 weeks of age and had serial DEXA measurements performed at 9, 15, and 19 weeks of age. Within 3–4 weeks, mice started on the HFD were significantly heavier than controls irrespective of the age the diet was started. Upon initiation of HFD at 6 or 9 weeks, mice rapidly increased their rate of weight gain and attained similar weight compared to 3 week HFD mice with the exception of 9 week 60F10S which failed to catch‐up by 19 weeks. Calculated energy intake was greatest in the first week following HFD initiation. Intake tended to be higher throughout the remainder of feeding in all HFD groups. DEXA measurements at 9 weeks of age revealed animals fed HFD for 3 or 6 weeks showed similar percent fat that was approximately double controls (17 vs 32%). By 15 and 19 weeks of age all HFD groups showed a doubling of percent fat compared to controls (22 vs 44%‐15 wk and 25 vs 46%‐19 wk). Independent of start age, GTT at 17 weeks revealed HFD fed mice were glucose intolerant compared to control animals with a 60% increase in glucose area under the curve. In summary, these two HFD diet patterns produced similar obesity phenotypes. The age at which these HFD were initiated did not impact the percent fat or glucose tolerance measured after 8–14 weeks of feeding.