Some factors (autoclaving, addition of ethoxyquin, drying, degree of grinding) influencing utilisation of carotene from plant origin were investigated.
Low storage of vitamin A in liver and low excretion of carotene in faeces, when fresh lucerne was given, indicated that carotene‐destroying enzymes of plant origin are likely to act before the lucerne is eaten and while it is passing through the intestines.
Addition of ethoxyquin to autoclaved lucerne improved the utilisation of carotene. This indicates nonenzymic oxidation of carotene in the digestive tract.
Carotene was more effectively utilised from lucerne meal than when given as green lucerne even if autoclaved and with ethoxyquin added.
It seems that the influence of non‐enzymic factors on the availability of carotene from various dried plants is small and uniform, because carotene was utilised equally from these sources.
The particle size (degree of grinding) had no significant influence on the utilisation of carotene from lucerne meal and it seemed that coarser meals could be used without hindering the utilisation of carotene or other carotenoids by chicks.