Soybean meal (SBM) is a byproduct from the oil-industry widely used as protein supplement to ruminants worldwide due to its nutritional composition, high protein concentration, and availability. However, the dependency on monocultures such as SBM is problematic due to price fluctuation, availability and, in some countries, import dependency. In this context, oilseeds from the mustard family such as rapeseed/canola (Brassica napus and Brassica campestris), camelina (Camelina sativa), and carinata (Brassica carinata) have arisen as possible alternative protein supplements for ruminants. Therefore, the objective of this comprehensive review was to summarize results from studies in which canola meal (CM), camelina meal (CMM), and carinata meal (CRM) were fed to ruminants. This review was based on published peer-reviewed articles that were obtained based on key words that included the oilseed plant in question and words such as "ruminal fermentation and metabolism, animal performance, growth, and digestion". Byproducts from oil and biofuel industries such as CM, CMM, and CRM have been evaluated as alternative protein supplements to ruminants in the past two decades. Among the three plants reviewed herein, CM has been the most studied and results have shown an overall improvement in nitrogen utilization when animals were fed CM. Camelina meal has a comparable amino acids (AA) profile and crude protein (CP) concentration to CM. It has been reported that by replacing other protein supplements with CMM in ruminant diets, similar milk and protein yields, and average daily gain have been observed. Carinata meal has protein digestibility similar to SBM and its CP is highly degraded in the rumen. Overall, we can conclude that CM is at least as good as SBM as a protein supplement; and although studies evaluating the use of CMN and CRM for ruminants are scarce, it has been demonstrated that both oilseeds may be valuable feedstuff for livestock animals. Despite the presence of erucic acid and glucosinolates in rapeseed, no negative effect on animal performance was observed when feeding CM up to 20% and feeding CMN and CRM up to 10% of the total diet.
Keywords: animal growth; animal performance; digestibility; milk production; mustard; oilseed; ruminal fermentation.