BW and body composition

The pups from mothers fed the maternal 41.7%, 58.3%, and 66.6% fat diets were weaned at a significantly higher BW than pups from mothers fed the 8.3% and 25% fat diets ((29)). Fourteen weeks later, the BW of offspring raised by mothers fed ≥41.7% fat was still significantly higher than those fed ≤25% fat. The effect of higher-fat diets was greater in males than in females (Table 1, Supporting Information Table S2). After the offspring diets were introduced at 18 weeks of offspring age, mice fed the offspring HFD (oHFD) gained more weight than those fed the offspring LFD (oLFD). Weight on oHFD increased more when mothers had been fed diets with ≥41.7% fat. Hence, both maternal and offspring diets significantly affected offspring BW (Supporting Information Figure S1, Supporting Information Table S2). At the end of the experiment (day 81), BW of the male offspring fed oHFD was 56.7 ± 7.7 g in offspring raised by mothers fed 8.3%, 58.9 ± 8 g in offspring of mothers fed 25%, 72.6 ± 11.6 g in offspring of mothers fed 41.7%, 75.6 ± 10.9 g in offspring of mothers fed 58.3%, and 70.1 ± 6.3 g in offspring of mothers fed 66.6%. Equivalent values for females were 51.5 ± 6.6 g (offspring of mothers fed 8.3%), 52.3 ± 6.1 g (offspring of mothers fed 25%), 62.5 ± 8.8 g (offspring of mothers fed 41.7%), 62.2 ± 7.1 g (offspring of mothers fed 58.3%), and 57.2 ± 7.4 g (offspring of mothers fed 66.6%). For offspring maintained on oLFD, the trends were similar, but the weights were lower (Table 1).

TABLE 1. Variable information at specific time points in both genders Sex Maternal 8.3% fat Maternal 25% fat Maternal 41.7% fat Maternal 58.3% fat Maternal 66.6% fat Maternal 8.3% fat Maternal 25% fat Maternal 41.7% fat Maternal 58.3% fat Maternal 66.6% fat oLFD oLFD oLFD oLFD oLFD oHFD oHFD oHFD oHFD oHFD BW at baseline (g) Male 50.9 ± 3.6 49.4 ± 4.8 58.2 ± 7.4 56.6 ± 5.4 55.7 ± 5.2 48.4 ± 3.2 49 ± 4.5 57.2 ± 6.8 57.4 ± 5.7 54 ± 4.7 Female 44.4 ± 5.8 40.8 ± 3.5 48.4 ± 4 49.6 ± 4.6 47.6 ± 3.3 42.6 ± 4.1 43.5 ± 4.6 50.2 ± 4.2 49.2 ± 4 48.5 ± 5.2 BW at day 81 (g) Male 53 ± 3.7 55 ± 7.5 64.8 ± 8.9 64.4 ± 8.1 61.4 ± 8.3 56.7 ± 7.7 58.9 ± 8 72.6 ± 11.6 75.6 ± 10.9 70.1 ± 6.3 Female 47.2 ± 5 43.9 ± 3.8 53.7 ± 4.5 55.6 ± 6.6 54.2 ± 7.4 51.5 ± 6.6 52.3 ± 6.1 62.5 ± 8.8 62.2 ± 7.1 57.2 ± 7.4 Body fat content at baseline (g) Male 6 ± 1.7 4.9 ± 1.6 9.3 ± 5.2 8.6 ± 4.5 8.2 ± 3.7 5.2 ± 1.9 5 ± 2.8 8.8 ± 3.9 9.2 ± 4.2 8.4 ± 2.8 Female 6.8 ± 3 5.6 ± 1.7 9.7 ± 2.2 9.9 ± 3 10.7 ± 2.7 6.7 ± 1.9 6.8 ± 2.2 11.3 ± 3.8 9.1 ± 3.1 11.1 ± 4 Body fat content at day 81 (g) Male 10.5 ± 2.6 12.3 ± 3.7 17.4 ± 6.6 17.2 ± 7 15.8 ± 5.3 14.9 ± 5.1 16.5 ± 6.4 24 ± 6.8 26.5 ± 7 23.7 ± 5.3 Female 10.3 ± 3.5 8.2 ± 2.5 14.6 ± 3.1 15.9 ± 5.5 17.2 ± 5.8 15.4 ± 5 15.3 ± 5.2 24.5 ± 8.4 22.3 ± 5.7 20.4 ± 6.4 Body lean mass at day 81 (g) Male 39.8 ± 3 40.4 ± 5.3 44.7 ± 3.7 44.7 ± 2.7 43 ± 3.9 39.6 ± 3.4 40.4 ± 3.5 46.9 ± 5.8 48.4 ± 4.9 44.5 ± 2.5 Female 34.7 ± 4.5 33.2 ± 3.7 36.6 ± 2.8 37 ± 2.7 34.7 ± 4 33.6 ± 3.1 34.6 ± 3.2 36 ± 3.6 37.4 ± 2.3 34.4 ± 3.1 DEE-day (KJ/d) Male 70.9 ± 13.4 71.8 ± 13.3 71.7 ± 10.7 77.3 ± 11.6 77.8 ± 13.5 78.8 ± 19.3 67.3 ± 13.5 75.6 ± 11.8 79 ± 14.8 78.9 ± 9 Female 67.2 ± 15.6 67 ± 17.5 72.6 ± 9.4 79.6 ± 12.2 65.8 ± 12.8 64 ± 12.7 75.1 ± 15.1 73.4 ± 11.5 77.2 ± 9.8 62.8 ± 18.1 DEE-night (KJ/d) Male 73.9 ± 14.1 71.9 ± 14.2 77 ± 12.5 81.1 ± 13.6 79.5 ± 15.3 80.9 ± 17.4 67.7 ± 13.5 78.9 ± 15.5 83.2 ± 17.3 80.7 ± 8.9 Female 69.4 ± 16.3 70.5 ± 15.6 73 ± 10.6 80.3 ± 16 67.1 ± 12.8 66.7 ± 11.8 77.2 ± 13.9 73.7 ± 11.9 77.5 ± 11.2 63.4 ± 17.1 RER-day Male 0.8 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.7 ± 0.1 0.8 ± 0.1 0.7 ± 0.1 0.8 ± 0.1 0.7 ± 0.04 Female 0.8 ± 0.1 0.8 ± 0.1 0.8 ± 0.1 0.9 ± 0.1 0.8 ± 0.1 0.7 ± 0.1 0.8 ± 0.1 0.8 ± 0.1 0.7 ± 0.1 0.8 ± 0.1 RER-night Male 0.9 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.7 ± 0.1 0.8 ± 0.1 0.7 ± 0.1 0.8 ± 0.1 0.8 ± 0.04 Female 0.9 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.9 ± 0.1 0.7 ± 0.1 0.8 ± 0.1 0.7 ± 0.1 0.7 ± 0.1 0.8 ± 0.1

When baseline maternal effects were removed by normalizing the baseline to zero, the repeated measures general linear model (RM-GLM) in males over the 12-week experimental period showed that there were significant day and day × maternal diet effects on BW in both oLFD and oHFD groups (Figure 2A,B, Supporting Information Table S2). This interaction indicated that the maternal diet effect on offspring BW varied at different time points over the 12-week HFD exposure. To illustrate this effect, we selected day 1 (early phase), day 41 (midphase), and day 81 (late phase) to compare the differences among the five maternal dietary groups. In oLFD males, a significant maternal effect was found only at day 81, at which point the 41.7% fat and 58.3% fat groups had significantly higher BW change compared with the 8.3% fat group (4.4 and 5.6 g). In oHFD males, the 41.7% fat and 58.3% fat groups had significantly lower BW change than the 8.3% fat group at the early phase (2.1 and 1.6 g), and the 41.7% fat group also had significantly lower BW change (1.8 g) than the 25% fat group. However, in the midphase, there was no significant impact of maternal diet on BW change. Then, reversing the effect seen at the start of the HFD exposure, in the late phase, maternal dietary groups with 41.7% fat and above had significantly higher increases in BW than those with 25% fat or below (Figure 2A,B, Supporting Information Table S2). These data showed that maternal dietary fat levels had a larger effect on male offspring BW gain when they were exposed to oHFD than to oLFD. In females, BW changes over the experimental period analyzed by RM-GLM showed that there was no significant maternal diet effect, and although a significant day × maternal diet effect was found in oLFD females, there was no interaction of day and diet in oHFD females. In other words, the maternal fat exposure did not significantly affect weight gain on oHFD in females. This is illustrated by multi-time-point ANOVA that showed no maternal diet effect at day 1, day 41, and day 81 in both oLFD and oHFD females (Figure 2C,D, Supporting Information Table S2).

Baseline normalized body weight of male and female offspring after oLFD and oHFD were introduced: (A) male oLFD offspring; (B) male oHFD offspring; (C) female oLFD offspring; (D) female oHFD offspring. Significant effects of diets are indicated using superscript a, b, and c, i.e., groups that have the same letter did not differ significantly, and groups with a different letter differed significantly (p < 0.05). Values are means ± SD. From maternal 8.3%, 25%, 41.7%, 58.3%, and 66.6% fat groups, sample sizes for male oLFD offspring were 13, 10, 10, 10, 13, for male oHFD offspring were 13, 11, 11, 10, and 12, for female oLFD offspring were 12, 10, 13, 10, and 13, and for female oHFD offspring were 13, 10, 13, 10, and 13. GTT, glucose tolerance test; NS, no significance; oHFD, offspring high-fat diet; oLFD, offspring low-fat diet; TSE, TSE PhenoMaster for energy expenditure and physical activity measurement

Regression of average mean BW (between days 69 and 81) against both maternal and offspring dietary fat content was used to estimate the relative roles of these diets in the final BW. This showed that the maternal diet had a stronger effect on final BW than the offspring diet in both males and females (Supporting Information Table S3). For example, male mice that were fed the 41.7% fat diet gained between 3.9 g and 7.4 g more weight than those fed the 8.3% fat diet. But if the offspring diet was fixed at 41.7% fat, those whose mothers had been fed 41.7% fat during lactation gained up to 14.6 g more weight than those whose mothers were fed 8.3% fat.

Increases in total BW during the 12 weeks of the experiment were reflected in alterations in body composition (Supporting Information Table S2). The body fat mass of offspring at weaning gradually increased in line with the maternal dietary fat level ((29)). After 14 weeks on chow, these values were all higher, but the pattern was maintained. There were no significant differences between the dietary groups at baseline in both males and females (Table 1, Supporting Information Table S2). RM-GLM over 12 weeks showed that both maternal and offspring effects significantly impacted offspring body fat content. Both male and female offspring raised by mothers fed 41.7% fat and above had significantly greater body fat compared with those fed 25% fat and below at the end of the experiment (day 81) (Supporting Information Figure S2A-D, Supporting Information Table S2). At day 81, fat mass of oHFD males was 14.9 ± 5.1 g in male offspring raised by mothers fed 8.3%, 16.5 ± 6.4 g in offspring of mothers fed 25%, 24 ± 6.8 g in offspring of mothers fed 41.7%, 26.5 ± 7 g in offspring of mothers fed 58.3%, and 23.7 ± 7 g in offspring of mothers fed 66.6%. Equivalent values for females were 15.4 ± 5 g (8.3%), 15.3 ± 5.2 g (25%), 24.5 ± 8.4 g (41.7%), 22.3 ± 5.7 g (58.3%), and 20.4 ± 6.4 g (66.6%) (Table 1).

When baseline fat content was normalized to zero, RM-GLM of body fat changes in males over the 12-week experimental period showed that there were significant day and day × maternal diet effects in both oLFD and oHFD groups, similar to the pattern observed with BW changes (Figure 3A-D, Supporting Information Table S2). This suggested that the maternal diet effect on offspring body fat changes also varied over time. Multi-time-point (day 11, day 41, day 81) ANOVA showed that there were significant differences between maternal dietary groups at day 41 and day 81 in oLFD groups and at day 81 in oHFD groups (Supporting Information Table S2). However, RM-GLM of body fat changes over the 12-week experimental period showed that there was no significant maternal dietary effect or day × maternal diet effect in both oLFD and oHFD females. This was consistent with BW changes, showing that maternal diet did not affect the susceptibility of female offspring to diet-induced obesity (Figure 3A-D, Supporting Information Table S2).

Baseline normalized body fat content and body lean mass content of male and female offspring after oLFD and oHFD were introduced. (A,B) Body fat change in male oLFD and oHFD offspring. (C,D) Body fat change in female oLFD and oHFD offspring. (E,F) Body lean mass change in male oLFD and oHFD offspring. (G,H) Body lean mass change in female oLFD and oHFD offspring. Significant effects of diets are indicated using superscript a, b, and c, i.e., groups that have the same letter did not differ significantly, and groups with a different letter differed significantly (p < 0.05). Values are means ± SD. From maternal 8.3%, 25%, 41.7%, 58.3%, and 66.6% fat groups, sample sizes for male oLFD offspring were 13, 10, 10, 10, and 13, for male oHFD offspring were 13, 11, 11, 10, and 12, for female oLFD offspring were 12, 10, 13, 10, and 13, and for female oHFD offspring were 13, 10, 13, 10, and 13. oHFD, offspring high-fat diet; oLFD, offspring low-fat diet

Lean body mass also differed between offspring. RM-GLM of lean body mass over the 12-week experimental period showed that there were significant maternal diet and day × maternal diet effects in both males and females (Supporting Information Figure S2E-H, Supporting Information Table S2). At day 81 of the experimental period, lean body mass of the male offspring fed oHFD was 39.6 ± 3.4 g in male offspring raised by mothers fed 8.3%, 40.4 ± 3.5 g in offspring of mothers fed 25%, 46.9 ± 5.8 g in offspring of mothers fed 41.7%, 48.4 ± 4.9 g in offspring of mothers fed 58.3%, and 44.5 ± 2.5 g in offspring of mothers fed 66.6%. Equivalent values for females were 33.6 ± 3.1 g (8.3%), 34.6 ± 3.2 g (25%), 36 ± 3.6 g (41.7%), 37.4 ± 2.3 g (58.3%), and 34.4 ± 3.1 g (66.6%) (Table 1). Hence, maternal dietary fat of 58.3% had a positive effect on lean body mass in both male and female offspring. No significant offspring dietary effect was observed on lean body mass in both males and females (Supporting Information Figure S2E-H, Supporting Information Table S2).

When baseline lean mass was normalized to zero, RM-GLM of lean body mass changes over the 12-week experimental period showed that there were significant day and day × maternal diet effects in both oLFD and oHFD groups for males. However, in females, no such effects were observed. Multi-time-point ANOVA showed that there are significant differences between maternal dietary groups at day 41 and day 81 in oLFD groups and at day 11, day 41, and day 81 in oHFD groups in males (Figure 3E-G, Supporting Information Table S2).

A final dissection was conducted to estimate the effects of both maternal and offspring effects on organ sizes (Supporting Information Figure S3A,B, Supporting Information Table S5). In male offspring, there were significant differences between maternal dietary groups in the masses of subcutaneous fat (SUB), mesenteric white adipose tissue (MWAT), gonadal WAT (EpWAT), retroperitoneal WAT (RpWAT), heart, lungs, liver, pancreas, small intestine, cecum, colon, kidneys, testes, and brain, as well as significant differences between offspring dietary groups in the masses of SUB, MWAT, EpWAT, RpWAT, and cecum (ANOVA; Supporting Information Table S5A-S5B). Generally, males from groups with maternal 41.7% fat and above had significantly higher WAT masses than those from 25% fat and/or below. Males raised by mothers fed 41.7% fat and above also had significantly greater masses of the other tissues except for the small intestine, which was heaviest in the 8.3% maternal fat group. All oHFD males had significantly higher WAT masses than oLFD males by, on average, about 46% (Supporting Information Table S5A-S5B). However, after correction for overall differences in BW (using ANCOVA), significant differences in the masses were observed only between maternal groups in EpWAT, lungs, small intestine, cecum, testes, and brain and between offspring dietary groups in SUB, EpWAT, brown adipose tissue, liver, and cecum (GLM; Supporting Information Table S5A-S5B).

In female offspring, significant differences in the organ masses were found in SUB, MWAT, EpWAT, RpWAT, heart, lungs, stomach, small intestine, cecum, colon, kidneys, and brain between maternal dietary groups and in SUB, MWAT, EpWAT, RpWAT, liver, spleen, cecum, colon, and kidneys between offspring dietary groups (ANOVA; Supporting Information Table S5C-S5D). Similar to males, maternal groups fed 41.7% fat and above had significantly higher fat deposition in WAT. All oHFD females had significantly higher WAT masses than oLFD females by, on average, about 52% (Supporting Information Table S5C-S5D). After adjusting for overall BW, significant differences in all WAT masses disappeared, and only the following were significant: heart, lungs, stomach, small intestine, cecum, kidneys, and brain between maternal groups and SUB, heart, lungs, liver, cecum, colon, kidneys, and brain between offspring dietary groups (GLM; Supporting Information Table S5C-S5D).

FI and energy intake

The gross energy content of the food was 15.9 kJ/g for oLFD and 19.2 kJ/g for oHFD. At baseline, gross FI/energy intake (EI) did not differ significantly between maternal and offspring dietary groups in both males and females (Figure 4, ANOVA; Supporting Information Table S2). FI and EI over days 1 through 81 of the experimental period showed that oHFD males and oLFD females raised by mothers fed 58.3% fat had significantly higher FI/EI than those from 8.3%-fat-fed and 25%-fat-fed mothers. Highly significant day effects were observed in all male and female oLFD and oHFD groups, and significant day × maternal diet effects were also found in male oLFD and female oHFD groups. However, multi-time-point (day 1, day 41, and day 81) ANOVA showed that no significant differences in FI/EI were observed in male oLFD and female oHFD groups (Figure 4, RM-GLM, post hoc Tukey; Supporting Information Table S2).

Food intake (grams) and energy intake (kilojoules) changes after oLFD and oHFD were introduced to offspring raised by different maternal diets. (A,B) Food intake in male offspring. (C,D) Food intake in female offspring. (E,F) Energy intake in male offspring. (G,H) Energy intake in female offspring. Values are means ± SD. From maternal 8.3%, 25%, 41.7%, 58.3%, and 66.6% fat groups, sample sizes for male oLFD offspring were 13, 10, 10, 10, and 13, for male oHFD offspring were 13, 11, 11, 10, and 12, for female oLFD offspring were 12, 10, 13, 10, and 13, and for female oHFD offspring were 13, 10, 13, 10, and 13. For food intake with significant p values using repeated measures general linear model, different lowercase letters indicate significant differences between maternal groups, as assessed by Tukey post hoc. “8.3, 25, 41.7, 58.3, and 66.6” are short for the 8.3% fat, 25% fat, 41.7% fat, 58.3% fat, and 66.6% fat groups. GTT, glucose tolerance test; oHFD, offspring high-fat diet; oLFD, offspring low-fat diet; TSE, TSE PhenoMaster for energy expenditure and physical activity measurement

GTT

There was no significant effect of maternal diet on fasting glucose or glucose disposal in both males and females independent of offspring diet (Figure 5A-F, RM-GLM, ANOVA, and GLM [BW as a covariate]; Supporting Information Table S4). A significantly lower effect in area under the curve (AUC) for glucose was observed in oLFD females compared with oHFD females, but not in delta-AUC (normalized fasting glucose to 0) (Supporting Information Table S4). Pooling all the data, there was a significant positive but weak relationship between BW and AUC in both sexes (male: y = 11.79x + 1,612, R2 = 0.072; female: y = 16.36x + 786.1, R2 = 0.098) (Figure 4G,H, Supporting Information Table S4), as well as a significant BW effect, when BW was included as a covariate in AUC, indicating that the significant maternal effect in females stemmed from the significant BW effect. Lean mass was also considered as a covariate, but there was no lean effect in females. After accounting for the effect of BW, the maternal effect disappeared (Supporting Information Table S4). These results indicated that both maternal and offspring diets did not have additional impacts on glucose tolerance beyond their effects on BW.

Glucose tolerance test in offspring after 11 weeks of oLFD and oHFD exposure. Glucose disposal in (A,B) males and (C,D) females. GTT-AUC in (E) males and (F) females. Linear regression between BW and GTT-AUC in (G) males and (H) females. Values are means ± SD. From maternal 8.3%, 25%, 41.7%, 58.3%, and 66.6% fat groups, sample sizes for male oLFD offspring were 8, 6, 5, 6, and 9, for male oHFD offspring were 9, 7, 5, 6, and 7, for female oLFD offspring were 8, 6, 7, 7, and 9, and for female oHFD offspring were 9, 6, 8, 6, and 9. BW, body weight; GTT-AUC, glucose tolerance test-area under the curve; oHFD, offspring high-fat diet; oLFD, offspring low-fat diet

PA, RER, and DEE

PA, RER, and DEE were analyzed separately for day and night, and PA was also analyzed separately in oLFD and oHFD groups. RM-GLM over 3 days showed that there were neither significant maternal diet nor time × maternal diet effects in both oLFD and oHFD males, in both day and night. In females, only in oLFD groups in the night, a significantly higher locomotor activity was observed only in the 8.3% fat group (20,451 more counts = 47.91% higher) compared with the 66.6% fat group, but significant maternal diet and time × maternal diet effects were not found in oHFD groups, in both day and night. The offspring diet also did not have an impact on the male and female offspring PA (Figure 6A-D, RM-GLM; Supporting Information Table S4). Therefore, offspring PA was independent of both maternal and offspring diet.

Physical activity, RER, and DEE measurements in offspring after 11 weeks of oLFD and oHFD exposure. Physical activity over 3 days in (A,B) male and (C,D) female offspring. RER over 3 days in (E,F) male and (G,H) female offspring. DEE over 3 days in (I,J) male and (K,L) female offspring. Overall (M,N) RER and (O,P) DEE during day and night in male and female offspring. Values are means ± SD. From maternal 8.3%, 25%, 41.7%, 58.3%, and 66.6% fat groups, sample sizes for male oLFD offspring were 4, for male oHFD offspring were 4, 4, 3, 4, and 4, for female oLFD offspring were 4, 4, 4, 3, and 4, and for female oHFD offspring were 4. For RER and DEE with significant p values using general linear model, different lowercase letters indicate significant differences between maternal groups, and different capital letters indicate significant differences between offspring groups, as assessed by Bonferroni post hoc. DEE, daily energy expenditure; oHFD, offspring high-fat diet; oLFD, offspring low-fat diet; RER, respiratory exchange ratio

RER of offspring raised by 25%-fat-fed mothers remained at a higher level in the day and reached the highest level in the night in both sexes (Table 1, Supporting Information Table S4). After accounting for effects of BW, all males and females raised by mothers fed 25% fat had the highest RER in both day and night. All oLFD groups had significantly higher RER than oHFD groups, even after accounting for BW. RER for oLFD males was both 0.9 ± 0.1 in the day and night; equivalent values for oHFD males were 0.7 ± 0.1 and 0.8 ± 0.1. RER for oLFD females was 0.8 ± 0.1 and 0.9 ± 0.1 in the day and night and for oHFD females was 0.7 ± 0.1 and 0.8 ± 0.1 in the day and night (Figure 6E-H,M,N, ANOVA/GLM, post hoc Tukey/Bonferroni; Table 1, Supporting Information Table S4).

Males from mothers fed 58.3% and 66.6% fat had significantly higher DEE than those fed 41.7% (by 4.7 and 4.8 KJ/d), 25% (by both 8.6 KJ/d), and 8.3% (by both 3.3 KJ/d) in the day. The offspring of mothers fed 58.3% fat had the highest DEE in the night (82.2 ± 15.6 KJ/d), and the 66.6%-fat-fed offspring were second highest (80.1 ± 13.1 KJ/d), whereas the 25%-fat-fed offspring had the lowest in both day and night (day: 69.6 ± 13.6 KJ/d, night: 69.8 ± 14 KJ/d). Females raised by mothers fed 58.3% fat had the highest DEE (day: 78.2 ± 11 KJ/d, night: 78.7 ± 13.4 KJ/d), whereas the 66.6%-fat-fed females had the lowest (day: 64.3 ± 15.7 KJ/d, night: 65.2 ± 15.2 KJ/d). DEE of those from the 41.7% fat group was also at a significantly higher level than that of those fed 25% and less fat (2 and 7.4 KJ/d), as well as those fed 66.6% fat (8.7 KJ/d) in the day, and this group had 5- and 8.1−kJ/d higher DEE than those fed 8.3% and 66.6% fat in the night (Figure 6I-L,O,P, ANOVA, post hoc Tukey; Table 1, Supporting Information Table S4). DEE was strongly influenced by BW. After adjusting for BW, in both day and night, male offspring raised by mothers fed 8.3% fat had the highest DEE compared with the other males, and females raised by 25%-fat-fed mothers had the highest DEE. Those whose mothers were fed 66.6% fat had the lowest DEE in both sexes, indicating effects of both BW and independently maternal diet on DEE (GLM, post hoc Bonferroni; Supporting Information Table S4). oLFD males had significantly lower DEE compared with oHFD males in both day and night (by 2.1 and 1.5 KJ/d). No significant differences were observed in oLFD and oHFD females. Similarly, after adjusting for BW, both male and female oLFD groups had higher DEE than oHFD groups (Figure 6I-L, Figure 6O,P, ANOVA/GLM, post hoc Tukey/Bonferroni; Supporting Information Table S4).

Results overview

Offspring raised by mothers fed ≥41.7% fat during lactation were weaned at a higher BW than those raised by mothers fed ≤25% fat, and this difference persisted after 14 weeks of feeding on chow diet. The maternal diets with ≥41.7% fat had a greater influence on BW of male than female offspring, and they exaggerated BW gain and fat deposition when offspring were fed HFD in males. In both sexes, maternal diet played a more important role than offspring diet in determining BW and adiposity.

Glucose homeostasis was dependent on BW. Once such effects were removed, there was no residual impact of maternal or offspring diets. Postnatal maternal HF consumption altered FI and EI in oHFD males and oLFD females. However, maternal and offspring dietary effects did not impact PA. After removing the BW effect, male offspring raised by 8.3%-fat-fed mothers and female offspring raised by 25%-fat-fed mothers had the highest DEE levels, and mice whose mothers were fed 66.6% fat had the lowest BW-adjusted DEE.