Scott: Efficacy of hydrothermal reactors, enzymes and additives to increase the utilization and safety of canola meal for livestock
Date: December 2016
Term: n/a
Status: Completed
Researcher(s): Tom Scott, Andrew Van Kessel, Denise Beaulieu, University of Saskatchewan, Saskatoon SK
SaskCanola Investment: $31,660
Total Project Cost: $151,660
Funding Partners: ACIDF
Project Summary
As canola production in western Canada continues to increase, one of the remaining obstacles to maximizing investments is generating significant value from the meal, particularly as an animal protein source. Researchers at the University of Saskatchewan designed a study to evaluate how canola meal could be further treated using hydrothermal processing to increase the value and safety of canola meal and make it more competitive as a feed ingredient. Further research is required to facilitate pre-digestion and how this can be managed without excess cost.
Canola production in western Canada has increased exponentially in the last several decades and one of the remaining obstacles to maximizing investments is generating significant value from the meal, particularly as an animal protein source. There is also an increased interest in using processing and additives to increase the utilization of nutrients of canola meal (solvent and extruded non-solvent extracted) with a focus on “pre-digestion” using a hydrothermal reactor. There is also expected to be significant benefit of these conditions and additives on reducing pathogens associated with food safety.
In order for pre-digestion to occur the technology must support optimum conditions (temperature, moisture, pH and time) for enzymes to cause reactions that reduce antinutritional factors and improve the intake and utilization of nutrients by animals. One of the most significant antinutritional factors in canola meal is phytic acid or phytate. This molecule is used by plants to store phosphorus, however, it is also associated with reduced availability of starch, amino acids and minerals, besides phosphorus. Phytase, an enzyme commercially used in feed, helps break down phytate. However, there can be variable responses in animals due to the fluctuations in gut pH and time for hydrolysis.
Researchers at the University of Saskatchewan designed this study to evaluate how canola meal could be further treated during the production process or as a separate process developed by the feed industry and involved hydrothermal processing. The focus of this project has been on evaluating different combinations of: temperature; moisture; time; pH (using standard acids like HCl but also organic acids that may be retained in the feed and act as antimicrobials or pre-biotics); and enzymes to modify different sources of canola meal and improve the intake and utilization of nutrients from these ingredients. The study also examined if additives could be used to: a) improve feed value (intake, digestibility) of canola meal by hydrolyzing or breaking down antinutritional factors; b) reduce microbiological loads in feed; and c) maintain low pathogen levels in the ingredient, the diet it was added to, and potentially in the gut of the animals fed. The overall goal is to increase the value and safety of canola meal and make it more competitive as a feed ingredient.
Based on lab-bench preliminary trials to optimize hydrothermal conditions and additives, the results showed that phytate levels in canola meal could be reduced by 20 to 80%. Reasons for the variability in the response requires further research, as results indicate further improvement is still possible. It was determined that a significant proportion of the phytate could be hydrolyzed within 30 min, 40 C, high moisture (>200%, which is a concern due to requirements for storing digested material dry or in a wet preserved method) and with a pH of 4.0. The pH was reduced with a variety of acids available to the feed industry with highest levels of enzyme activity when citric or malic acids were used. However, these were not superior to use of HCl. Similar results were observed when solvent extracted and extruded non-solvent extracted sources of canola meal were used. A preliminary trial using protease to increase protein availability shows no major change, but further evaluations are required.
It was apparent that the finished product was effectively sterile, as is the case following use of high heat during solvent extraction of canola oil and drying meal. However, the question remained would the organic acids and pH of the hydrothermally digested products prevent recontamination. It was evident using Salmonella treated material that antimicrobial activity was maintained after hydrothermal treatment.
A feeding study was also conducted to evaluate the impact of hydrothermal processing on pig performance. Solvent extracted canola meal (30%) of diet was treated with 50% moisture, 40 C, and pH reduced with HCl, and organic acids citric, malic or lactic for 30 minutes. Only the diets with organic acid were supplemented with phytase and the one with HCl was maintained as a control.
Based on the results of the feeding studies, there was an improved utilization of phytate with organic acids and phytase and this resulted in improvements of digestibility of dry matter, energy, protein and some amino acids. The improvement in energy digestibility indicates improved feeding value for the acid treated HTR process canola meal. Based on the value of other energy sources, such as tallow, these additional calories would be worth approximately $80 per tonne. Moreover, an improvement in energy content means that the canola meal would be suitable for more classes of livestock and at high inclusion level. Further research will clarify if comparable results can be obtained with a more “practical” HTR treatment.
Overall, the present study suggests that there is a potential to reduce the increasing feed cost by utilizing low-cost co-products such as canola meal and to benefit animals by providing them with more available nutrients and environment with less P and overall manure output. Issues that still need to be addressed in future research relate to the high moisture level required to facilitate pre-digestion and how this can be managed without excess cost.