Progress 02/01/23 to 01/31/24
Outputs
Target Audience:Dairy farmers, food supply chain stakeholder, students (college, graduate, post-doctoral fellows, veterinary medicine), visiting scholars, organizations and communities of sustainability enthusiasts, feed industries, research communities. Changes/Problems:The lab-based bioprocessing experiments ran into a few unexpected observations. First, fungal growth occurred during the 2nd step of bioprocessing (i.e. bacterial-driven anaerobic fermentation), which resulted in lower organic acids production, less pH drop, and incomplete ensiling. This is most likely due to the presence of air in the fungal fermented wheat straw (an aerobic process), which in turn inhibited the subsequent bacterial fermentaiton (an anaerobic process). The problem was resolved by using fermentation bags, instead of Mason jars. Additionally, we found that the fungal fermentation of wheat straw required moisture level around 70% to be most effective. In the subsequent step, combining the fungal-treated wheat straw with FFV would bring the mixed materials to about 80% moisture. This would be too wet for bacterial-based fermentation, plus the potential challenge of large amounts of leachate if scaled-up on the farm. Furthermore, the wheat straw used in our lab studies had to be sterilized prior to the introduction of selected fungi. For future scale-up and on-farm adoption, relevant cost and feasibility must be considered along with environmental factors. The project team with collective expertise in bioengineering, animal nutrition, veterinary health, farm and systems-based management and integration, will work together to find ways to address the challenges, identify viable options, and assess relevant synergies and tradeoffs. What opportunities for training and professional development has the project provided? A post-doctoral fellow (Dr. Sun, in Dr. Hu's lab at U Minnesota) has focused on carrying out specific tasks within Objective 1, along the way expanding his knowledge and research experience into developing novel feeds from food waste and crop residues with enhanced nutritional feeding values for dairy cattle. He has presented relevant results at several conferences, and authored 2 peer-reviewed papers based on this USDA project. He is also supervising undergraduate as well as master students engaged in relevant research in the lab. All of these further broaden the spectrum of his professional development in the field. A new post-doctoral fellow joined Dr. Hu's lab (U Minnesota) and was mentored by senior researcher Dr. Sun under the guidance of Dr. Hu. Two graduate students participated in the project and received training from thisUSDA grant in Dr. Hu's lab. An undergraduate student was mentored and participated in project-related activities. This student (a hispanic american) was sponsored by MnDRIVE/LS-NSSA Summer Internship Program designed to involveunder-represented ethnicgroups from community colleges. An undergraduate student, guided by Drs. Dou and Baker, received comprehensive training, with activities ranging from literature search and review to organization of materials for scientific wirting and to conference presentation. The student completed her senior theses based on the research she conducted as part of this USDA project. She also participated in and co-authored the peer-reviewed publication (Baker et al., 2024). A Dairy Production Medicine Fellow (with a VMD degree) continues to be a key player in this project. Guided by the faculty team members (Drs. Dou, Baker, Bender, Pitta), this Fellow has been actively involved in food waste upcycling via livestock related activities, including (i) coordination and working with local dairy producers for on-farm research as well as outreach, (ii) systematic literature review, data extraction and database construction, data analysis, interpredition of data to identify patterns and trends, (iii) integrated examination of food waste feeding opportunities and potential impacts on nutrition, feed cost, and resource benefits on commercial farms, and (iv) presentation at an international conference on food waste to animal feed. A group of veterinary students (3 are involved, led by one particularly passionate student) has been exploring ways to recycle and upcycle their own food waste into useful materials. They conducted literature search, compared different options of food waste composting models (device, scope and cost, energy consumption and potential carbon footprint), eventually selecting and setting up a table-top composting machine that is most appropriate for their purposes. They have produced dry and odor-free "product" from food waste generated in the student communal kitchen consistently. Based on nutritional analysis results, the students recognized that the product could be given a higher-value use as animal feed instead of soil amendment (compost). Supported via the USDA project and guded by project faculty members and through a progressive and integrative learning process, the students have gained first-hand experience regarding food, social and environmental responsibility, and sustainability which may affect them for years to come. A new post-doctoral fellow has recently joined Dr. Dou's lab in person after having worked remotely under Dr. Dou's supervision during the first phase of the project. With a background in agronomy and agricultural production systems, he has expanded his research interests (and potential career horizon) across the interface of crop systems and livestock systems (feed and feeding). He is the first author of a recent relevant publication (Wang et al., 2024), Field evidence on animal performance when fed food waste derived feeds: A review, in collaboration with veterinarians and animal nutritionists. He will play a key role in the remaining work of this USDA project (dairy feeding trial, LCA analysis, etc.). How have the results been disseminated to communities of interest?Dissemination events and activities during year 2 of the project: Continued engagement and expansion of food supply chain stakeholders into project related activities, including key players at a fruit processing company (the business owners, floor supervisors, and operators); waste management services; local farming communities (a Melonite dairy farm, a beef farming co-op, a feed processor-supplier). Presentations at multiple conferences and workshops of local, regional, and international levels. A Special Issue on leveraging livestock to upcycle food waste, via Resources, Conservation and Recycling (Impact Factor 13.2). The special issue is organized by project team members led by Drs. Dou and Shurson, and designed to attract global audience of broad disciplines. Project team members contributed 5 peer-reviewed papers. What do you plan to do during the next reporting period to accomplish the goals? Work in process: (i) in lab bioprocessing to obtain novel feeds for in vitro digestibility testing, (ii) scale up of fungal fermentation of wheat straw with FFV ensiling to 50 kg size. Palatability test with dairy cattle will be performed for the produced feed. Chase a new research lead: on discovering the lignin changes during fungal fermentation of wheat straw, including the metabolized products from lignin, de-polymerization of lignin during fungal processing, and the relationship of lignin modification and available energy to the ruminant utilization of fiber rich materials. Complete the investigation of novel feed impact when fed to dairy cows at the whole animal level, the rumen microbiota level, as well as the carbon footprint (enteric gas emissions, particularly methane). A feeding trial using Calan gates and the GreenFeed device will be conducted to enable relevant data and sample collection. Contenue the educational as well as future agricultural expertise training activities. Carry on with outreach efforts and broaden potential impact whenever opportunities present.
Impacts
What was accomplished under these goals?
Accomplishment related to Objective 1: We have accomplished the following tasks during year 1 (2022-2023): screened fungal strains for wheat straw lignin reduction, investigated moisture content and temperature on wheat straw fermentation, evaluated fungal co-fermentation of wheat straw and fresh fruit/vegetables (FFV), tried scale up of the fermentation from flasks to 1 kg fermentation bags, and attempted ensiling of fungal fermented wheat straw with FFV. During year 2 (2023-2024) of the project, we successfully produced enough materials through the sequential fermentation: fungal fermentation of wheat straw in 1 kg air-flow spawn bags followed by ensiling with FFV in 1 kg anerobic fermentation bags. In this work, we used a sequential fermentation strategy to process wheat straw and FFV discards into an alternative feeding material that could replace a portion of traditional total mixing ratio (TMR) of dairy feed without much inhibition of in vitro digestibility. The moisturized and grinded wheat straw and wheat straw mixed with FFV was first fermented and co-fermented with two previously screened fungal strains (Trametes versicolor and Pleurotus ostreatus) under aerobic condition in 1 kg air flow spawn bags for six weeks. The fermentation has resulted in the dry matter reduction of wheat straw or wheat straw/FFV mix by at least 20% but selectively reduced lignin content by 35-55%, resulting in higher cellulose-lignin ratio. The fungal strains during co-fermentation of wheat straw/FFV mixture could also efficiently utilize soluble nitrate, and certain amount of sulfate and phosphate for biomass accumulation and metabolisms. The fungal fermented wheat straw or wheat straw/FFV mix was then mixed with additional FFV at ratio of close to 1:1 (by weight) and fermented with natural microbes in anaerobic fermentation bag (1 kg capacity) for two weeks. Around 6% (DM basis) of soluble sugar in the mix was completed converted to organic acids, resulting in pH reduction from 5 to around 3.5. Total produced lactic acid accounts for 80% of total fatty acids produced, which account for 9-10% of DM of the fermented mix. The results have been reported in a peer-reviewed publication (Sun et al., 2024). Preliminary evaluation of in vitro digestibility (IVD) of the sequential fermented feed indicated improved or comparable digestibility compared with the control of standard TMR. Work is in progress to generate additional (treatments) samples for additional in vitro testing. Accomplishment related to Objective 2: The impacts of novel feed incorporated in dairy diets on multiple performance indicators at the whole animal level have been determined through two feeding trials. One involved adding culled fresh fruit into the daily TMR diet and fed to cows at a research dairy farm, the other occured on a local commercial dairy farm where culled fruit discards were ensiled with grass hay prior to being used in feeding the cows. Animal performance indicators were obtained, including dry matter intake, milk yield, milk components (fat and protein yields as well as concentrations), and milk urea nitrogen (MUN). The results have been reported at conferences as well as in a peer-reviewed publication (Baker et al., 2024). The impacts of fruit-based novel feeds on rumen microbial characteristics and enteric methane emissions will be determined in year 3. Accomplishment related to Objective 3: The implication of novel feed incorporated into dairy diets and partially displacing conventional feed ingredients on resources and key environmental parameters have been evaluated based on data obtained from the feeding trial described above. These included the amounts of land, water, fertilizer and herbicideds/pesticides to spare, and GHG emissions (in CO2-e) to offset. The evaluation involved substitution-avoidance analysis as well as life-cycle analysis (LCA) approach. The results have been reported (Baker et al., 2024). Techno-economic analysis will be performed in year 3. Accomplishment related to Objective 4: Educational efforts and activities included the creation of 2 new teaching modules, one on Doughnut Economics applicable to sustainable food systems, which was added into Global Food Security and One Health course; the other on how research can inform policy, focusing on food waste to animal feed, which was added into Becoming Clinician Scientist, a course in veterinary corriculum for second year students.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Sun, X., Dou, Z., Shurson, G., Hu, B., 2024. Bioprocessing to upcycle agro-industrial and food wastes into high nutritional animal feed for sustainable food and agriculture systems. Resources, Conservation and Recycling 201, 107325
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Baker, L., J. Bender, J. Ferguson, D. Pitta, S. Rassler, S. Chann, Z. Dou. Culled citrus waste fed to dairy cows: Animal performance, sustainability implication, and lessons learned. Resources Conservation Recycling, https://doi.org/10.1016/j.resconrec.2024.107452. 2024
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Wang, Y., S. Rassler, D. Stefanovski, J. Bender, J. Deutsch, T. Chen, Z. Cui, Z. Dou. Field evidence on animal performance when fed food waste derived feeds: A review. Resources Conservation Recycling, https://doi.org/10.1016/j.resconrec.2024.107411. 2024
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Sun, X., Dou, Z., Shurson, G., Hu, B., 2023. Fungal bioprocessing of wheat straw and fresh fruit and vegetable discards to produce cattle feed for enhanced sustainability. Resources, Conservation and Recycling 199, 107251
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Progress 02/01/22 to 01/31/23
Outputs
Target Audience:Food supply chain stakeholder; Dairy farmers; Local citizens and enthusiasts of resources/environment/climate/farming sustainability; Students of highschool, college, graduate, and post-doctoral fellows; Professional groups; Research communities. Changes/Problems:An opportunity emerged somewhat unexpectedly, when we learned about a fruit processing/cold storage facility where large amounts of culled fruit waste are routinely generated. We seized the opportunity by conducting a dairy feeding trial with culled fresh citrus added to the diet fed to grouped cows as compared to control. This has opened doors for new ideas and farm application potential. Further investigation is being pursued. What opportunities for training and professional development has the project provided?An undergraduate student was mentored for learning to use lifecycle analysis approach to investigate potential impacts of feeding human-unfit fruit waste to cows on resources (land, water, fertilizer, energy) as well as carbon footprint mitigation. The student had the opportunity to present her findings at an international conference (virtual). A recent graduate (VMD) has been participating in food waste upcycling via livestock related activities, including (i) coordination and working with local dairy producers for on-farm research, (ii) literature search and data extraction for analysis, (iii) integrated examination of food waste feeding opportunities and potential impacts on nutrition, feed cost, and resource benefits on commercial farms (to be purpused). A post-doctoral fellow has focused on carrying out specific tasks within Objective 1, along the way expanding his knowledge and research experience into developing novel feeds from food waste and crop residues with enhanced nutritional feeding values for dairy cattle. He has presented relevant results at an international conference, and is preparing 2 mascripts for scientific journals. He is also supervising undergraduate as well as master students engaged in relevant research in the lab. All of these further broaden the spectrum of his professional development in the field. How have the results been disseminated to communities of interest?A number of dissemination events via various venues: 1. Engagement of food supply chain stakeholders via site-visits, in-person conversation, and small group meetings. 2. Involvement of highschool students via see-it-yourself tours and demonstrations. 3. Presentations at conferences/workshops of local/regional/international capacity, approximately 8 person-talks. 4. Relevant information provided to groups or individuals of varying background/interest, examples including annual conference for food animal veterinary practitioners, on-site do-it-yourself activities for visiting Penn Vet board of advisors, and visitors from the Earth Fund, local grassroot groups, private sectors, and extension personnel. What do you plan to do during the next reporting period to accomplish the goals? Research: The 2nd phase of scaling-up with sequential fermentation In vitro incubation with samples generated from the sequential fermentation processes On-farm ensiling of culled fresh fruit waste to test the utility of extending the shelf-life using Ag Bags Cow feeding trial with simultaneous determination of animal performance as well as enteric methane emissions Publication preparation: 5-6 manuscripts are planned for a special issue of the journal Resource Conservation and Recycling (RCR). The special issue focuses on food waste upcycling via livestock to address multiple sustainability objectives. Other: Continue educational effort and activities involving students Develop outline for a new course module on livestock and soceity Diseminate project findings via organized (e.g. annual conferences etc.) as well as impromptu events (ad hoc demands) Continue outreach via tours and field demonstrations, particularly involving food supply chain stakeholders
Impacts
What was accomplished under these goals?
Relevant to Objective 1: Two sets of laboratory-based research were carried out as described below. Fungal solid-state fermentation of wheat straw and its mixture with fresh fruit and vegetables (FFV). This consisted of a series of experiments to first screen different white-rot fungi for their delignification capacity using wheat straw as substrate. Two fungal strains, T. versicolor and P. ostreatus, were selected due to relatively higher lignin reduction than other fungi. P. ostreatus had a high selectivity for lignin reduction, whereas T. versicolor had highest degradation rate, even though it degraded lignin, cellulose and hemicellulose to similar extent. To preserve cellulose and hemicellulose, 15 days of fermentation was selected for T. versicolor, but 30 days for P. ostreatus. Subsequent experiments determined the suitable temperature to be 30 °C for both T. versicolor and P. ostreatus, and moisture to be 70% and 80% for P. ostreatus and T. versicolor, respectively, to attain the highest selectivity of lignin reduction. Next, FFV mixture was prepared from 10 types of fruits and vegetables and mixed with wheat straw to attain moisture content for fungal fermentation with the selected fungal strains above. Delignification appeared to decline while cellulose and hemicellulose degradation enhanced compared to wheat straw without FFV, more so for P. ostreatus than T. versicolor. Available sugar in the FFV substrates could have inhibited delignification process and accelerated cellulose and hemicellulose degradation. Moreover, longer fermentation time (30 days) was required for both T. versicolor and P. ostreatus to attain significantly (p < 0.05) reduced lignin concentration. Further, the data indicate an advantage of co-fermentation of wheat straw mixed with FFV, that is, soluble sugar and protein were converted into fungal biomass with enriched essential amino acids (AA), and a small amount of free AA. These would translate to enhanced feeding value and concurrently preventing spoilage and nutrient loss. Scaling up of fungal solid-state fermentation of wheat straw followed with ensiling with FFV. The solid-state fermentation process was scaled up from 250 mL shaking flasks to 1 kg air-flow spawn bags. Chopped wheat straw (1-5 cm) was moisturized (65% moisture content), then autoclaved prior to inoculation of the selected fungal mycelia and incubation at 28 °C for 30 days. Upon completion of fermentation, the moisture of the substrate reduced to 55-60%. The concentration of lignin was lower, while cellulose and hemicellulose were higher in P. ostreatus fermented wheat straw. T. versicolor fermented wheat straw showed lower cellulose and hemicellulose concentrations. The fermented wheat straw (and un-fermented wheat straw to serve as control) were then mixed with FFV at ratio of proximately 1:2 (wet basis) in 1 gallon Mason jar with airlock for ensiling at around 28 °C for 26 days with periodic sample collection and analysis. The pH reduced from 4.8 to around 3.6 within 10 days, together with near complete consumption of glucose and fructose. Meanwhile, lactic acid, acetic, propionic, and isobutyric acids were produced. The lactic acid production was higher and other VFAs (acetic, propionic, isobutyric acids) were lower in ensilage with P. ostreatus and T. versicolor fermented wheat straw compared to non-fermented wheat straw control. Using fungal fermented wheat straw to ensile with FFV improved lactic acid to total acids proportion (71-74%) compared to that of non-fermented wheat straw (67-68%). Also, at the end of the sequential fermentation with fungal-based aerobic fermentation of wheat straw first followed by bacteria driven anaerobic fermentation with the addition of FFV, the products showed higher soluble protein, rumen degradable protein, and relative feed value involving T. versicolor compared to that of P. ostreatus or that of non-fermented wheat straw treatment. Preliminary conclusion is that fungal pretreated wheat straw followed by ensiling with FFV is feasible to enhance the overall nutritional feeding value of the substrates that are otherwise under-valued (wheat straw) and prone to spoilage (FFV). Relevant to Objectives 2&3: Large amounts of fruit waste are generated at all stages of the food supply chain. Opportunities for repurposing and upcycling wasted fruit vary, depending on where and how it is generated as well as its biological and nutritional traits. A dairy feeding experiment was conducted that incorporated culled citrus fruit from a processing-repacking center. One hundred sixty cows were divided into 4 lactation groups based on days after calving/days in milk (DIM) and the level of milk production. Cows in each group were randomly assigned to and fed with control vs. fruit-added diets for 24 days. The control diets were total mixed rations (TMR) formulated to meet the animals' requirements, with corn silage, grass hay, ground corn, and a protein blend being the main ingredients. Relevant fruit-added diets had inclusion rates approximating 7 kg culled citrus (fresh weight) /cow/day, proportionally reducing conventional feed ingredients. Cows adapted to the fruit diets within a couple of days. Milk yields did not differ between control and the fruit diets. Milk fat and milk protein yields were not affected either. Milk urea nitrogen was variable across groups, but values were similar in each group when comparing control and fruit cows. The use of culled fruit in diet led to reductions in conventional feedstuffs, which in turn means decreases in feed cost and other production inputs. Implications on resources (e.g. land, water, fuel) and climate footprint mitigation are calculated for scenarios involving feeding the whole herd fruit-added diets. Potential benefits as projected are substantial when considering landfill emissions offset as well as lifecycle-based assessment associated with the replacement of conventional feed ingredients. Relevant to Objective 4: Educational efforts and activities were carried out, consisting of (i) the addition of 2 new teaching modules on food waste upcycling and livestock production into Global Food Security and One Health (roughly 70 students); (ii) educational tour and on-site demonstration for Dairy Leaders of the Future (about 100 highschool students); (iii) immersion with hands-on involvement of food waste upcycling research at the dairy (2 highschool seniors, 2 college senior, 1 dairy intern, 1 post-doctoral fellow).
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Dou, Z., J.D. Toth, D. Pitta, J. S. Bender, M. L. Hennessy, B. Vecchiarelli, N. Indugu, T. Chen, Y. Li, R. Sherman, J. Deutsch, B. Hu, G. C. Shurson, B. Parsons, L. D. Baker... Proof of Concept for Developing Novel Feeds for Cattle from Wasted Food and Crop Biomass to Enhance Agri-Food System Efficiency. Scientific Reports. https://www.nature.com/articles/s41598-022-17812-w
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Baker, L., J. Bender, D. Pitta, and Z. Dou. Culled fruit waste fed to dairy cows: Production response, Economic impacts, and Practical insights. International Conference on Resource Sustainability.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Sun, X., B. Hu, G. Shurson, and Z. Dou. Reform agro-industry by-products and crop residues for better feed to support sustainable farm animal production. International Conference on Resource Sustainability (icRS 2022)
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