show a higher capacity for storing fat in adipose tissue and for
oxidizing fatty acids in muscle that could explain their lower
tendency to manifest an HFD obesity-linked disorder such as
increased hepatic lipid content, though at the expense of
increased weight and adiposity gain [44]. In contrast, male
rodents are prone to develop obesity-linked disorders, and for
this reason have traditionally been more used than females in
animal studies investigating antiobesity effects of bioactive
compounds. All in all, it could be important to perform the
interventions in animals of both sexes, even if full characterization of samples is first conducted in the male animals.
6. The approval of experimental protocols and procedures by the
competent Bioethical Committee is mandatory before starting.
7. A relatively low dose of dietary vitamin A is advisable in the
experimental diets to maximize intestinal absorption of the
supplied carotenoids (especially beta-carotene), since carotenoid absorption can be repressed by preformed vitamin A [45].
8. It is important to replace the HFD in the cage feeders at least
twice a week, to avoid rancidity.
9. Pure carotenoids or carotenoids mixtures are usually dissolved
in oil. We recommend refined olive oil (not virgin olive oil),
because it is largely devoid of polyphenols, contains only trace
amounts of carotenoids, and provides good quantities of vitamin E as antioxidant. For some carotenoids, water-soluble,
relatively stable formulations (beadlets) can be obtained commercially [46] which contain the selected crystalline carotenoid
(s) together with additional components, typically DL-alphatocopherol, ascorbyl palmitate, corn oil, fish gelatin, sucrose,
and corn starch (e.g., provided by DSM Nutritional Products
Ltd.). The same formulation but without the carotenoids can
be provided by the manufacturer, to be administered to the
control groups. Also, food extracts enriched in a given carotenoid or carotenoid mixture can be used in the animal intervention experiments. When food extracts are used, it is important
to characterize their composition and stability.
10. Daily carotenoid administration through pipetting has the
advantage that it ensures good control over the actual dosage
but it requires animal handling skills and can be timeconsuming. Administration of carotenoids can also be carried
out through the diet, by mixing the selected pure carotenoid,
beadlets, or a food extract enriched in the selected carotenoid
(s) with a powdered HFD diet or including them in a pelletized
HFD. In the latter case, the experimental diets need to be
prepared by cold extrusion so as to protect the carotenoids
from heat treatment. When using supplemented diets, the dose
Mouse Models to Study Antiobesogenic Effects of Carotenoids
413
oxidizing fatty acids in muscle that could explain their lower
tendency to manifest an HFD obesity-linked disorder such as
increased hepatic lipid content, though at the expense of
increased weight and adiposity gain [44]. In contrast, male
rodents are prone to develop obesity-linked disorders, and for
this reason have traditionally been more used than females in
animal studies investigating antiobesity effects of bioactive
compounds. All in all, it could be important to perform the
interventions in animals of both sexes, even if full characterization of samples is first conducted in the male animals.
6. The approval of experimental protocols and procedures by the
competent Bioethical Committee is mandatory before starting.
7. A relatively low dose of dietary vitamin A is advisable in the
experimental diets to maximize intestinal absorption of the
supplied carotenoids (especially beta-carotene), since carotenoid absorption can be repressed by preformed vitamin A [45].
8. It is important to replace the HFD in the cage feeders at least
twice a week, to avoid rancidity.
9. Pure carotenoids or carotenoids mixtures are usually dissolved
in oil. We recommend refined olive oil (not virgin olive oil),
because it is largely devoid of polyphenols, contains only trace
amounts of carotenoids, and provides good quantities of vitamin E as antioxidant. For some carotenoids, water-soluble,
relatively stable formulations (beadlets) can be obtained commercially [46] which contain the selected crystalline carotenoid
(s) together with additional components, typically DL-alphatocopherol, ascorbyl palmitate, corn oil, fish gelatin, sucrose,
and corn starch (e.g., provided by DSM Nutritional Products
Ltd.). The same formulation but without the carotenoids can
be provided by the manufacturer, to be administered to the
control groups. Also, food extracts enriched in a given carotenoid or carotenoid mixture can be used in the animal intervention experiments. When food extracts are used, it is important
to characterize their composition and stability.
10. Daily carotenoid administration through pipetting has the
advantage that it ensures good control over the actual dosage
but it requires animal handling skills and can be timeconsuming. Administration of carotenoids can also be carried
out through the diet, by mixing the selected pure carotenoid,
beadlets, or a food extract enriched in the selected carotenoid
(s) with a powdered HFD diet or including them in a pelletized
HFD. In the latter case, the experimental diets need to be
prepared by cold extrusion so as to protect the carotenoids
from heat treatment. When using supplemented diets, the dose
Mouse Models to Study Antiobesogenic Effects of Carotenoids
413