X-Message-Number: 29811
Date: Sat, 1 Sep 2007 12:51:47 -0700 (PDT)
From:
Subject: 239'th update on fly longevity experiments
This is the 239'th update of my fly longevity experiments. Average
temperature was 23.8 C during this run. Estimated maximal longevity using
the formula (363 - T*11.2) is 97 days.
This run was designed to determine whether flies are harmed by
glycotoxins. To eliminate the possibility of heating destroying enough
heat labile nutrients to cause malnutrition, only 25% of the fly food
used in most bottles was heated. Since 75% of the fly food used in the
experimental bottles was unheated, then nutrient intake would have to be
at least 75% of that of control bottles, and malnutrition would be
extremely unlikely. To keep glycotoxin levels as high as in the previous
experiments the period of heating at 150 C was extended from 30 to 50
minutes. One bottle used 100% heated fly food to serve as a positive
control, and thiamin or benfotiamine were added as a test to scavenge
glycotoxins. Note that neither thiamin nor benfotiamine had any positive
effect in previous runs (#167 & #171). This means that unheated fly food
either has no glycotoxins, or that flies are not harmed by them.
Alas, survival was very poor in all bottles, which I attribute to
using an older breeding bottle with many diseased flies in it. No
consistent effect of any intervention was noted, and it appears that
disease vectors primarily drove the survival results. No definitive
conclusions regarding glycotoxins can be inferred from the results of
this run.
Run #239 Percent Survival on Day
supplement 12 20 30 36 43 56 65 72 79 84
___________________________________________________
control one 96 67 44 33 15 7 0 - - -
control two 92 71 38 33 8 4 0 - - -
heated fly food 25% 73 55 27 23 14 9 5 0 - -
heated fly food 25% 77 46 27 19 15 12 8 8 0 -
+benfotiamine 10 mg 70 52 30 11 7 0 - - - -
" 20 mg 75 66 41 38 13 6 0 - - -
" 40 mg 79 75 43 25 18 0 - - - -
+thiamine 13 mg 85 70 56 37 15 0 - - - -
" 25 mg 64 46 18 5 0 - - - - -
" 50 mg 74 59 33 15 7 4 4 4 4 0
heated fly food 100% 74 52 30 15 11 0 - - - -
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