In: Math
PART 2:
The researchers hypothesized that mice consuming more saturated fats will have a higher probability of becoming obese and developing symptoms of diabetes. To test for dietary effects on the development of metabolic disease, the researchers collected additional data from the two cohorts of mice. They measured the fasting blood glucose levels and they performed an insulin tolerance test (effect of a dose of insulin on blood glucose level). Data are reported as means (±SEM).
Fasting blood glucose (mM) |
|
Lard (N=14) |
Fish oil (N=14) |
11 (0.22) |
10.32 (0.23) |
Blood glucose (% of the time 0 level) |
||
Time after insulin injection (min) |
Lard |
Fish oil |
0 |
100 |
100 |
30 |
59.8 (3.05) |
49.8 (4.09) |
60 |
54.5 (3.51) |
37.2 (4.07) |
90 |
63.1 (3.91) |
39.1 (4.09) |
120 |
75.6 (3.06) |
56.9 (3.31) |
Using a t-test, determine whether the difference in the fasting blood glucose levels for the lard-fed and the fish oil-fed mice is significant.
Plot the glucose over time data.
Did the two groups of mice differ in their response to the same dose of insulin? At which time points?
What conclusions can you make about the effect of the type of dietary fat on carbohydrate metabolism?
PART 3:
To determine whether the difference in the microbiota is responsible for the difference in the weight gain or just a consequence of the different diet, the researchers raised mice for 11 weeks on either a lard or fish-oil diet. Then they took two new groups of mice and treated them with antibiotic to kill their gut microbiota. These mice then received transplants of the microbiota from the mice that had been fed either lard or fish oil for 11 weeks. All of the “transplanted” mice were maintained on a lard diet for 3 weeks to see if there was a difference in their weight gain.
Weight gain of “transplanted” mice after 3 weeks on lard diet (% initial) |
|
Lard microbiota |
Fish-oil microbiota |
41.3 |
21.5 |
35.6 |
21.7 |
43.4 |
39.7 |
41.6 |
30.9 |
23.7 |
29.5 |
27.2 |
25.6 |
41.2 |
26.4 |
28.6 |
29.5 |
35.0 |
11.2 |
38.7 |
24.5 |
Was there a significant difference in the weight gain in these two groups of mice?
What conclusion can you make about the effect of the microbiota composition versus the diet on weight gain?
What additional information would you want to have to support your conclusion?