Hempseed Meal (hemp protein powder or presscake) from monoecious varieties is higher in the anti-nutritional factor Phytic Acid, which is a problem for some animals and humans. It also reduces iron and zinc assimilation. Read more at:
“Evaluation of Protein Concentration, Amino Acid Profile and Antinutritional
Compounds in Hempseed Meal from Dioecious and Monoecious Varieties,” by Russo and Reggiani. American Journal of Plant Sciences, 6, 14-22.
Feed industries need new rich-protein fodder for animal, to increase meat, milk and egg productions. The remaining hemp meal after extraction of oil (which has its own commercial value), could be a new rich protein source available for use as animal feed. HSM shows a good protein content (34%), an interesting AA profile with elevated levels of arginine (but slightly poor in lysine) and a discrete digestibility of protein. In ruminants, heat treatment of hemp was shown to partially increase protein digestibility although such treatment leads to an increase of costs . Such costs for HSM need to be comparable to other protein feeds to become a viable alternative on commercial farms .
The evaluation of antinutritional compounds in HSM varieties, put in evidence the extremely high levels of phytic acid. From this point of view, HSM from dioecious varieties is better than that from monoecious varieties. As mentioned above, the restricted limit of 20% of HSM in animal diet allows lowering the concentration of antinutritionals and in particular of phytic acid. However, it is important to monitor phytate content in monogastric animal, since exposure of animals to high level of phytate over the long term could cause important nutritionally deficiencies, especially for iron and zinc . To increase the use of HSM in feed would be desirable breeding for low content of phytate. Otherwise, a research has to be undertaken to identify mutants with low phytic acid.”