Production of DHA Rich Algae biomass as
Cattle Feed Supplement to Enhance Milk Quality
1. Principle Investigator(s) and Cooperator(s):
PI Dr. Shulin Chen, Professor, Department of Biological Systems Engineering, Washington State University 99164-6120; Phone: (509)335-3743; Fax: (509) 335-2272
Co PI Zhanyou Chi, Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164-6120; Phone: (509)335-6239 Fax: (509) 335-2272;
2. FUNDING REQUEST: $30,000
3. TOTAL PROJECT DURATION: January 1, 2007 through December 31, 2007
4. Project Objectives and Rationale
The objective of this study is to develop a cost-effective algal cultivation process to convert under-valued cull potatoes to high-value docosahexaenoic acid (DHA) that has significant beneficial effects in the treatment of neurological and cardiovascular diseases as well as in infant brain and ocular development. The DHA enriched algal biomass will then be used as a feed additive for dairy cows to enhance the nutritional value of the milk.
DHA is an important w-3 polyunsaturatted fatty acids (PUFA). It is the component of the photoreceptor cells of infant retinas and is also involved in the development of infant brain tissue. The inclusion of supplementary DHA in infant formulas is strongly recommended by the World Health Organization (WHO). Also, research continues to demonstrate the need for DHA beyond infancy. Furthermore, studies suggested a positive correlation between DHA consumption and the reduced risk of age related neurological disorders, such as Alzheimer’s and dementia. As a result, DHA is not only used as additives in infant formulas, but also in adult dietary supplement in food and beverage. Example foods are cheeses, yogurts, spreads and dressings, and breakfast cereals. Other markets include foods for pregnant and nursing women and applications in cardiovascular health. These markets may have much greater growth potential than infant formulae.
Nutritionists believe that the desired ratio of w-6 to w-3 fatty acids should be from 3:1 to 5:1. However, the typical American diet due to its strong emphasis on vegetable oil consumption has caused this ratio to be irrationally high and might be a major factor in the high rates of heart disease and other health issues being experienced by Americans. w-3 PUFAs from enriched food has been suggested as way to improve this required ratio. Although fish is the best dietary source of omega-3, unfortunately, most American people prefer to milk and meat. Thus, supplementation of omega-3 in the Americans’ favorite food is a better choice.
Fish oil is currently the conventional source of omega-3 PUFA. However, there are some limitations of fish oil as a source such as peculiar taste, odor, stability problems, and the difficult and expensive purification of these acids from low-grade fish oil. In addition, the fish stocks are subject to seasonal and climatic variations. It is reported that fish, like humans, are not capable of synthesizing PUFA de novo. Much of their PUFA is derived from the primary producer in the oceanic environment: the microalgae. In fact, DHA produced from heterotrophic algal culture is taking on a more and more important and gradually substituting role. Production of omega-3 with algae fermentation and supplementing the produced omega-3 in the daily consumed food is a trend.
This proposed project offers an attractive alternative for omega-3 PUFA production and supplementation in food. It addresses three of BIOAg’s targeted areas as below:
(1) This process will convert the under-value cull potatoes to high-value omega-3 fatty acid, which addresses the priority area of bioproducts. Development of new markets for the cull potato is essential to the profit margins of the potato producers because the cost to grow the culls is $70-120/ton while presently they can be sold as an animal feed for only about $10-20/ton. Converting the culls to a value added bioproduct is an excellent way to develop new markets and overcome the cost to produce the culls, since they can provide starch, protein, vitamins, and salt nutrients for the fermentation process. By converting these culls into DHA, it will not only benefit the DHA manufacturers, in that this will significantly reduce the medium cost of the production process, but also the farmers, because the high value added product will better offset the production costs.
(2) The omega-3 enriched algae biomass will be fed to dairy cows. This addresses the priority area of organic dairy development. The cow will benefit from higher intakes of algal biomass because these algae contain a high level of protein, amino acids, lipids and vitamins, which are crucial for cows’ growth. Studies have shown that DHA enriched algae biomass enhanced the disease immunity of farmed fish. Some beneficial roles of DHA to fish probably work for cattle also.
(3) The cow milk quality will be enhanced by the supplementation of omega-3. This addresses the priority area of food quality. Dietary supplements containing DHA for dairy cow could help promote marketing of milk based upon its DHA content. Study showed that the inclusion of fish oil in the diet of grazing dairy cows deeply affects the fatty acids profile of milk fat. Concentrations of CLA, TVA and omega-3 PUFA were significantly increased, which represents a positive impact upon dietetic quality of milk. Thus, the omega-3 enriched milk can provide a favorite dietary source of omega-3 for Americans. Also, the omega-3 enriched milk, as the raw material, can be further developed to more favorite food, such as cheeses and yogurts.
Another advantage of this project is that using the cow as the omega-3 “extractor” can significantly reduce the high purification cost.
5. Methodology and Procedures
(1) Developing a high cell density Schizochytrium limacnum SR21 algal cultivation from cull potato
This project has been supported by Washington State Potato Commission (WSPC) and WSU IMPACT center from 2005. Schizochytrium limacnum SR21 was used for the DHA production. Potato hydrolyzed broth (HPB) was used as the carbon and nitrogen source in the culture medium, with some mineral salts added. Progresses have been made in optimizing the culture condition of Schizochytrium limacnum SR21. With the optimized culture condition, >40 g/L dry algae biomass and >9.0 g/L DHA can be produced. With studies’ going on, the productivity will be further increased. To reach an even higher biomass density (>100 g/L) in the fermentation process, a “two step” strategy fed batch culture will be developed, as the optimal condition of temperatures, carbon source concentrations, nitrogen source concentrations, and dissolved oxygen for algal growth and DHA formation are found to be different. In this study, at first, the optimal culture conditions for each of the two phases will be determined. Then, a protocol, which maintains the best conditions for algae growth at first and then shifts to the optimal condition for DHA accumulation, will be developed. Some of these tasks are undergoing and all these tasks will be finished by June 2007.
(2) Assessing the possibility of using algal biomass as additives in dairy feed.
The dairy feeding study will be conducted at the WSU Dairy Center. Dairy cows in mid-lactation will be randomly assigned to the experimental groups corresponding to 3 different feeding. Each group of cows will be fed with 4 kg concentrate/cow/day (the control group), concentrate mixed with 750 g algae dry biomass and concentrate mixed with 1500 g algae dry biomass. Feed samples will be analyzed for dry material, crude protein, crude fat and ash according to AOAC (1990) and neutral detergent fiber, acid detergent fiber and acid detergent lignin. Composite milk samples will be collected from four consecutive milkings on the 2 last days of each period. Milk composition (fat, protein) then will be determined and compared, in terms of both saturated and unsaturated fatty acids. The cow feeding experiment will be carried out from June 2007, and will be finished at December 31, 2007.
Budget:
Salary/Wages / $19,000Materials and Supplies / $10,000
Travel / $1,000
Total / $30,000