Progress 10/01/04 to 12/31/12
Outputs
OUTPUTS: Experiments were conducted to determine modification of bioactive lipids produced by the gut microbial population in ruminant species. Invited presentations were given on rumen lipid metabolism and the formation of bioactive lipids by the gut microbial population at the following conferences; Cornell Nutrition Conference, Cargill Consultant Meeting sponsored by Elanco, Nutrition Consultant Meeting sponsored by Church & Dwight, inc., Western Veterinarians Meeting,Old Troy Mill Dairy Influencer Meeting, Cornell Dairy Management Conference, Novus Dairy Management Conference, Amer Assoc. Bovine Practitioners, Florida Ruminant Nutrition Conference, and Elanco Dairy Consultant Workshop. Two papers were presented at the national meetings of the American Dairy Science Association in Phoenix, AZ. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Industry benefits from the results of this project by using the basic information discovered in development and testing of new products. Farm producers would then benefit from the project by having additional products available to improve productive efficiency of their operations and to potentially produce foods for human consumption that better conform to nutritional guidelines. Consumers then benefit from development of new food products that offer nutritional advantages for improved health and well being. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The major accomplishments of this project were to describe in detail the pathways of lipid biohydrogenation by bacteria in the rumen of dairy cattle. Previous work on the biochemical pathways done in the 1970s and 1980s concluded that rumen biohydrogenation was a simple process resulting in transitory increases in a few FA intermediates. However, recent analyses from this project have demonstrated an impressive array of trans-18:1 and CLA intermediates. This project undertook a series of studies to investigate the details of the biohydrogenation pathway using creative approaches and modern techniques. Specifically, fatty acids were labeled with stable isotopes and incubated in in vitro rumen culture systems. Perhaps the most challenging part was the identification of the FA intermediates containing the label and for this the P.I. sometimes collaborated with lipid chemists. The initial work by Jenkins and coworkers was with oleic acid. They found that oleic was isomerized to trans C18:1 intermediates in which the double bond ranged from carbon 6 to carbon 16. The complex biohydrogenation pathways that would yield these intermediates are quite different from the simple one-step conversion of oleic acid to stearic acid that had been assumed previously. The project then examined the biohydrogenation pathways for linoleic using isotopically-labeled linoleic acid. Again they showed the pathways are complex resulting in an impressive array of fatty acid isomers. For example, it was found that rather than a single CLA isomer being produced during the biohydrogenation of linoleic acid, over 12 individual isomers were produced with the proportions and amounts of these changing depending on dietary components and rumen conditions. Results from this project have pushed back the boundaries of our understanding of rumen biohydrogenation and its impact on milk fat composition. The principal investigator's original contributions have coincided with the development of nutrigenomics and the recognition that some fatty acid intermediates produced in small quantities during rumen biohydrogenation are potent regulators of metabolism and gene expression.
Publications
- Burns, T. A.,A.K.G. Kadegowda, S. K. Duckett, S. L. Pratt, and T. C. Jenkins. 2012. Palmitoleic (16:1 cis-9) and cis-vaccenic (18:1 cis-11) acid alter lipogenesis in bovine adipocyte cultures. Lipids 47:1143-1153.
- Wu, Z., J. K. Bernard, R. B. Eggleston, and T. C. Jenkins. 2012.Ruminal Escape and Intestinal Digestibility of Ruminally Protected Lysine Supplements Differing in Oleic Acid and Lysine Concentrations. J. Dairy Sci. 95:2680-2684.
- Headley, S., L. H. Boone, J. A. Coverdale, T. C. Jenkins, J. L. Sharp and K. L. Vernon. 2012. Dietary supplementation of CLA in horses: effects on bone turnover, synovial prostaglandin E2, and gait kinematics. J. Anim. Sci. (In Press).
- Headley, S., J.A. Coverdale, T. C. Jenkins, C. M. Klein, J. L. Sharp, and K. L. Vernon. 2012. Dietary supplementation of CLA in horses increases plasma CLA and decreases plasma arachidonic acid, but does not alter body fat. J. Anim. Sci. (In Press).
- Burns, T. A., S. K. Duckett, S. L. Pratt, and T. C. Jenkins. 2012. Palmitoleic acid (C16:1) reduces lipogenesis and desaturation in bovine adipocyte cultures. J. Anim. Sci. 1143-1153.
- Harrison, J., R. White, R. Kincaid, E. Block, T. Jenkins, and N. St. Pierre. 2012. Effectiveness of potassium carbonate sesquihydrate to increase dietary cation-anion difference in early lactation cows. J. Dairy Science 95:3919-3925.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Experiments were conducted to determine modification of bioactive lipids produced by the gut microbial population in ruminant species. Invited presentations were given on rumen lipid metabolism and the formation of bioactive lipids by the gut microbial population at the following conferences; 2011, Elanco Dairy consultant Workshops, Dec 6-9, Syracuse and Buffalo, NY. 2011, Penn State Dairy Nutrition Conference, Nov 9-11, Grantsville, PA 2011, Southeast Dairy Management Conference, Nov 2, Macon, GA 2011, ADSA Discover Conference, Oct 10-14, Itasco, IL 2011, Amer. Assoc. Bovine Practitioners, Sept 22-24, St. Louis, MO. 2011, International Ingredient Corporation, Nutrition Advisory Board, St. Louis, June 21-23. 2011, Land O Lakes Dairy Production Consultant Seminar, Wisconsin Dells, WI, June 9-12. 2011, Church & Dwight, Inc Consultant Workshop, May 9-11. 2011, Diamond V Dairy Consultant Workshop, Cedar Rapids, IA, May 2-3. 2011, World Ag Expo, Tulare, CA, Feb 9-11 Two papers were presented at the national meetings of the American Dairy Science Association in New Orleans. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: nutrition consultants, producers, industry representatives, and academic research and teaching faculty. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
An experiment was run to determine how quickly bioactive lipids, namely CLA, compounds change in ruminal contents in response to the addition and removal of unsaturated fat from the diet. The main CLA examined were cis-9, trans-11 CLA and trans-10, cis-12 CLA. Four dual-flow continuous fermenters were fed 60 g/d of 1:1 forage (alfalfa hay) to concentrate mix in two equal portions at 0800 and 1600 h. Diets were fed to flasks for four 12-d periods each divided into 3 phases; 1) a control diet for d 1-4 (CON1), 2) a diet with 4% added soybean oil for d 5-8 (SBO), and 3) the control diet for d 9-12(CON2). Samples of culture contents were taken at 0 (just prior to feeding), 2, and 4 h after the morning feeding on all days except d 5 and d 9. On d 5 and d 9, samples were taken hourly for 12 h starting just prior to the morning feeding. Results are expressed as g fatty acid/100 g total fatty acids. During the CON1 phase, regular rhythmic changes in fatty acid profile occurred daily after each morning feeding that were characterized by increased (P < 0.05) proportions of C18:2 (average increase of 10.4 percentage units) and cis-9, trans-11 CLA, and decreased (P < 0.05) proportions of stearic acid, trans-10 C18:1 and trans-10, cis-12 CLA. Linoleic acid averaged 11.5 during CON1 and peaked at 33.3% immediately after the addition of soybean oil (d4h1). Linoleic acid averaged 26.1% and 16.4% during SBO and CON2 phases, respectively. Stearic acid showed little change from SBO to CON2 phases (averaging 9.6 and 9.5%, respectively). Trans-10, cis-12 CLA proportions averaged 0.61% during CON1, increased gradually over the SBO phase, and peaked at 5.38% at the start of CON2 (d 8h 0). Trans-10 C18:1 averaged 0.62% over CON1 and peaked at 6.12% during CON2 (d9h0). The results of this study showed that the introduction of soybean oil into the diet causes an immediate increase in linoleic acid concentration in ruminal contents that is accompanied by little change in stearic acid and slow-developing increases in trans-10, cis-12 CLA and trans-10 C18:1.
Publications
- Lee, Y. J. and T. C. Jenkins. 2011. Identification of enriched conjugated linoleic acid isomers in cultures of ruminal microorganisms after dosing with 1-13C-linoleic acid. J. Microbiology 49:622-627..
- Lee, Y. J. and T. C. Jenkins. 2011. Biohydrogenation of Linolenic Acid to Stearic Acid by the Rumen Microbial Population Yields Multiple Intermediate Conjugated Diene Isomers. J. Nutr. 141:1445-1450
- Klein, C. M. and T. C. Jenkins. 2011. Docosahexaenoic acid elevates trans-18:1 isomers but is not directly converted into trans-18:1 isomers in ruminal batch cultures. J. Dairy Sci. 94:4676-4683.
- Jenkins, T. C. Fats and Protected Fats. 2011. pp 997-1003 in Encyclopedia of Dairy Sciences, 2nd edition. H. Ruginski, J. W. Fuquay, and P. F. Fox (Ed.), Academic Press, London.(Book Chapter).
- Klein, C. M., W. C. Bridges, and T. C. Jenkins. 2011. Biohydrogenation of docosahexaenoic acid into unsaturated 22-carbon fatty acid intermediates in ruminal batch cultures. J. Dairy Sci. (E-suppl. 1) 94:140.
- Klein, C. M., S. K. Thurmond, P. H. Morris, and T. C. Jenkins. 2011. Hourly changes in fatty acid profile of ruminal contents in continuous cultures as soybean oil is added and removed from the diet. J. Dairy Sci. (E-suppl. 1) 94:136.
- Jenkins, T. C. 2011. Managing the rumen environment to control milk fat depression. Penn State Dairy Cattle Nutrition Workshop, Grantville, PA, November 8-10.
- Jenkins, T. C. 2011. Managing the rumen environment to control milk fat depression. University of Georgia Southeast Dairy Herd Management Conference, Macon, GA, November 2.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Running of experiments and analysis of data Invited Lectures 2010, Diamond V Dairy Consultant Workshop, Cedar Rapids, IA, Nov 30-Dec 2 2010, ADSA Discover Conference on Transition Cows, Champaign, IL, Sept 20-23 2010, AFIA Liquid Feed Symposium, San Antonio, TX, Sept 14-16 2010, American Association of Bovine Practitioners, Albuquerque, NM, Aug 18-19 2010, Diamond V Dairy Consultant Workshop, Cedar Rapids, IA, June 29-30 2010, Land O Lakes Dairy Production Consultant Seminar, Wisconsin Dells, WI, June 15-17 2010, Land O Lakes Southern Region Sales Meeting, Atlanta, GA, June 10 2010, 4-state Dairy Nutrition & Management Conference, Dubuque, IA, June 9-10 2010, Hubbards Mills Dairy Tech Meeting, Minneapolis, May 25-26 PARTICIPANTS: Dr. Joe Harrison at Washington State University who ran animal trials demonstrating how potassium elevated milk fat percentage. Dr. Harrison also was involved in the planning and execution of studies at clemson University demonstrating changes in lipid metabolism by gut microbes that led to the potassium effects on milk fat percent. TARGET AUDIENCES: dairy producers, nutritional consultants, and industry serving producer feed needs. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Recent studies have reported increased fat percentages in milk of lactating dairy cattle when diets were supplemented with potassium carbonate. Because milk fat yield has been associated with ruminal production of certain conjugated linoleic acid isomers, this study was conducted to determine if increasing K exposure to ruminal microorganisms alters biohydrogenation and CLA production. Five dual-flow continuous fermenters were fed 60 g/d of a 1:1 forage (10% alfalfa hay and 90% corn silage) to concentrate mix in two equal portions at 0800 and 1600 h. Three of the five fermenters were injected just prior to each feeding with a 10% (w/w) stock potassium carbonate solution to provide the equivalent of 0.6 (K1), 1.2 (K2), and 1.8 (K3) g K/d. One of the remaining fermenters received no injection (K0) and the last fermenter (pHCON) was injected with adequate NaOH stock solution (10%, w/w) to match the pH observed for the K3 treatment. Diets were fed for four 10 d periods, with a total of four periods for the study. pH and acetate/propionate in fermenters increased (P < 0.05) linearly for K0 to K3. pH was the same but acetate/propionate was lower (P < 0.05) for pHCON compared with K3. Losses of oleic, linoleic, and linolenic acids averaged 216, 872, and 125 mg/d, respectively and were not affected by treatment. Stearic acid production changed (P = 0.14) from K0 to K3 (397, 449, 562, and 316 mg/d), but K3 and pHCON (206 mg/d) did not differ. Production of trans-10 C18:1 declined (P < 0.05) and trans-11 C18:1 increased (P < 0.05) linearly from K0 to K3, but pHCON and K3 were the same for both C18:1 isomers. Total CLA isomers (21 mg/d) were not affected by treatment, but shifting of isomers occurred. The cis-9, trans-11 and trans-9, trans-11 isomers increased (P< 0.05) linearly from K0 to K3, but K3 and pHCON did not differ. There was a numerical decrease in production of trans-10, cis-12 from K0 to K3 (11.4, 11.5, 7.9, and 8.5 mg/d), but its production remained high (13.2 mg/d) for pHCON. The results show that increasing K in the diet has effects on shifting fermentation and biohydrogenation pathways, which can only partially be explained by elevation of pH. The project this year resulted in a change in knowledge based on research results demonstrating a practical feeding solution to counter milk fat depression that causes widespread loss of milk income across the United states. US milk markets place a premium on fat content of milk but common feeding practices often lower milk fat percentage causing significant loss of income to the producer. The results of this project, in cooperation with researchers at the University of Washington, showed improvements in milk fat percentage when additional potassium is fed to cows, and also demonstrated the changes in rumen lipid metabolism that led to these changes. Changes in action already have taken place with articles on the research findings appearing in farm and dairy journals, and field recommendations occurring for additional potassium.
Publications
- Harrison, J. H., R. L. Kincaid, E. Block, and T.Jenkins. 2010. Effect of feeding potassium carbonate on milk fatty acids in early lactation cows. J. Dairy Sci. (E-suppl. 1) 93:781.
- Jenkins, T. C. E. Block, and J.H. Harrison. 2010. Shifts in fermentation and intermediates of biohydrogenation induced by potassium supplementation into continuous cultures of mixed ruminal microorganisms. J. Dairy Sci. (E-suppl. 1) 93:577.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Collection and analysis of data were completed on two continuous culture experiments to examine the impact of fat source and type on formation of conjugated linoleic acid isomers. Invited presentations on formation of conjugated linoleic acid isomers in ruminal contents and their impact on human health and animal performance were given at; 2009, Animal Science Departmental Seminar, Penn State Univ, Dec 4, State College 2009, Diamond V Dairy Consultant Workshop, Oct 25-28, Cedar Rapids, Iowa 2009, Minnesota Nutrition Conference, Sept 15-16, Owatonna, MN 2009, Florida Ruminant Nutrition Conference, Feb 10-11, Gainesville 2009, Southwest Nutrition Conference, Feb 26-27, Phoenix, AZ 2009, Western Canadian Nutrition Conference, Mar 10-11, Red Deer, Alberta, Canada 2009, Diamond V Dairy Consultant Workshop, Apr 14-15, Cedar Rapids, Iowa PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Target audiences were dairy producer groups who make decisions affecting milk composition and industry representatives that develop and supply nutritional products to meet producer needs. A number of invited presentations were made to both groups on research accomplishments connected with this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The intent of this project is to convert tallow from a simple high energy source to a rumen-protected fat source with improved handling qualities, enhanced nutritional value, and higher economic value. Past research suggests that the fatty acid profile of tallow might make it an excellent carrier for other nutrients, such as omega fatty acids known to have metabolic and physiologic benefits in dairy cattle. The approach of this project is to combine tallow with varying concentrations of omega fatty acids and convert the mixture to calcium salts. The hypothesis is that calcium salts of tallow containing the added fatty acids will provide protection from ruminal biohydrogenation beyond that observed for calcium salts of the pure omega fatty acids. Using this approach, calcium salts of tallow will be transformed to a dry powder that will function as both a rumen-inert fat to avoid rumen fermentation problems and also as a protected fat to avoid biohydrogenation Objective (s): a) Increase the amount of tallow that can be utilized in rations of dairy cattle by developing a value-added tallow calcium salt product that is capable of protecting essential nutrients from ruminal degradation. b) Improve the handling characteristics of tallow by their conversion to calcium salts. c) Determine the optimum combination of tallow and fish oil needed to provide maximum protection of omega-3 fatty acids (DHA and EPA) from microbial destruction in batch in vitro cultures and continuous cultures. Adding fat increased pH in the am and pm culture samples. The Ca salt protection technology increased culture pH values in the pm samples. There were protection technology by fat level interactions for DM and fiber digestibilities. Protection improved digestibilities of DM and fiber, but only when the added fat level was 4%. Total volatile fatty acid (VFA) concentrations were not affected by treatment except for the 2 h sample. At 2 h, the Ca salt protection technology lowered total VFA. The acetate to propionate ratios (A/P) were lower for unprotected fat compared to the protected fat sources. Lower ratios are indicative of higher inhibition of microbial growth. Thus, the Ca salt technology lessened the inhibition of microbial growth that normally is seen with added fat. Losses of linoleic acid (C18:2) and linolenic acid (C18:3) across the fermenters were indicative of a normal microbial biohydrogenation process. Likewise, there were losses of DHA and EPA from intake to outflow indicating biohydrogenation of these omega-3 fattyacids. Percent losses of DHA and EPA had a significant treatment by fat level interaction. Losses of DHA and EPA were lower when they were in the Ca salt form, but only for the lower level of supplementation. Ca salts provided no advantage in reducing ruminal losses of DHA and EPA when the fish oil levels were high. The overall impact of this project is to recycle tallow as an animal feed ingredient such that the resulting meat and milk can be used to enhance the nutritional status of the human population.
Publications
- Amoroch, A. K., T. C. Jenkins, and C. R. Staples. 2009. Evaluation of catfish oil as a feedstuff for lactating Holstein cows. J. Dairy Sci. 92:5178-5188.
- S. J. Freeman-Pounders, D. W. Hancock, J. A. Bertrand, T. C. Jenkins, and B. W. Pinkerton. 2009. The fatty acid profile of rye and annual ryegrass pasture changes during their growth cycle. Forage and Grazinglands, 30 January 2009.
- Jenkins, T. C. 2009. Milk fat depression: Interactions of ionophores, fat supplements, and other risk factors. Pp 172-184 in Proc. 70th Minnesota Nutrition Conference, Owatonna, Sept. 15-17.
- Jenkins, T. C., C. M. Klein, and G. D. Mechor. 2009. Managing milk fat depression: Interactions of ionophores, fat supplements, and other risk factors. Proc. 20th Florida Ruminant Nutrition Conference, pp. 1-11.
- Jenkins, T. C., C. M. Klein, and Y. J. Lee. 2009. New Insights on the Pathways of Lipid Biohydrogenation in the Rumen with Possible Implications on Animal Performance. Proc. 24th Southwest Nutrition and Management Conference, pp 90-105.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Activities Fish oils, including docosahexaenoic acid (C22:6, DHA) and eicosapentaenoic acid (C20:5, EPA) have been found to have human health benefits and are used as fat supplements in ruminants. Transfer of omega-3 fatty acids from the ruminant diet, to meat and milk products, depends on their escape from microbial biohydrogenation in the rumen. Fatty acids are often fed as calcium salts to reduce biohydrogenation and lessen the negative effects on fermentation. To determine if fish oil protection was enhanced when incorporated in a matrix of palm oil fatty acids, this study examined the effects of varying the ratio of fish oil and palm oil calcium salts on ruminal fermentation and biohydrogenation. Ruminal microorganisms maintained in continuous culture were exposed to diets with 5% added fat as soybean oil or as calcium salts of fish oil and palm fatty acids in three combinations (45/55, 75/25, and 90/10). A control diet and the four fat diets were fed to fermentors in a 5x5 Latin square with 10 d periods. As expected, the acetate/propionate ratio decreased (P < 0.05) when soybean oil was added to the diet (1.78 for the control and 1.30 for SBO). The acetate/propionate ratios for the fish oil diets were not different from the SBO diet (1.22, 1.07, and 1.07 for the 45FO, 75FO, and 90FO diets, respectively). Of the three combinations of fish oil tested, the 45FO and 75FO did not differ in the amounts of EPA (43.8% and 40.8%) or DHA (40.8% and 33.3% ) that disappeared. There were however, differences in EPA and DHA lost between 75FO and 90FO. Losses of EPA (59.8%) and DHA (55.8%) were greater (P < 0.05) for FO90 compared to either 45FO or 75FO. Events 2008, Ruminant Health and Nutrition Conference, March 25, Syracuse, NY 2008, New England Dairy Feed Conference, March 27, West Lebanon, NH 2008, Tri-State Dairy Nutrition Conference, April 22-23, Fort Wayne, IN 2008, Florida Ruminant Nutrition Conference, Jan 30 -31, Gainesville 2008, NIRSC, FeedAC, and NFTA joint conference, Feb. 13-14, Indianapolis, IN PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Target audiences include the livestock industry looking to feed specialized lipid compounds to cattle to enrich animal food products in omega fatty acids. Other target audiences include scientific and health organizations with an interest in understanding lipid metabolism in ruminant species. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Change in knowledge Results from the above experiments confirmed that fish oil fatty acids are degraded by ruminal microroganisms and revealed for the first time that rumen protection of DHA and EPA is diminished when fish oil comprises more than 75% of a fish oil/palm oil calcium salt mix.
Publications
- M. Vazquez-Anon, J. Nocek, G. Bowman, T. Hampton, C. Atwell, P. Vazquez, and T. Jenkins. 2008. Effects of feeding a dietary antioxidant in diets with oxidized fat on lactation performance and antioxidant status of the cow. J. Dairy Sci. 91:3165-3172.
- T. C. Jenkins, R. J. Wallace, P. J. Moate, and E. E. Mosley. 2008. BOARD-INVITED REVIEW: Recent advances in biohydrogenation of unsaturated fatty acids within the rumen microbial ecosystem. J. Anim. Sci. 86:397-412.(Invited Review)
- Moate, P. J., R. C. Boston, T. C. Jenkins, and I. J. Lean. 2008. Kinetics of ruminal lipolysis of triacylglycerol and biohydrogenation of long-chain fatty acids: new insights from old data. J. Dairy Sci. 91:731-742.
- Klein, C. M., T. C. Jenkins, and K. D. Murphy. 2008. Effects of varying levels of fish oil, fed as a calcium salt, on rumen fermentation and biohydrogenation in continuous culture. J. Dairy Sci. (Suppl. 1) 91:85.
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Progress 01/01/07 to 12/31/07
Outputs
Activities - new research projects related to fat effects on rumen lipid metabolim were conducted and analyzed Events - attended and presented papers at ADSA national meeting in San Antonio, Midwest ASAS Symposium, Pennfield nutrition symposium in williamsport, PA. Services - served as invited speaker for Novus International to tour the USA discussing fat effects on lavcatation peformance Products - publications in meeting proceedings and scientific journals
Impacts
Research results revealed the identity of 7 CLA isomers that can be confirmed as arising from the biohydrogenation of linoleic acid by ruminal microroganisms. Previously only one or two CLA isomers were recognized intermediates from linoleic acid biohydrogenation. The results of this research show that fatty acids consumed by cattle and other ruminant speicies are transformed by gut microrganisms to a mutitude of bioactive fatty acid intermediates called CLA. This defines carbons from linoleic acid as a direct precursor for the formation of these CLA, which are known to have potent physiological responses such as anticarcinogens and body fat inhibitors. Defining the pathways of CLA formation will, as done in this research, will allow mainpulation of physiologically important CLA that can enhance animal or human health.
Publications
- Vazquez-Anon, M., and T. C. Jenkins. 2007. Effects of feeding oxidized fat with or without dietary antioxidants on nutrient digestibility, microbial nitrogen and fatty acid metabolism. J. Dairy Sci. 90:4361-4367.
- Jenkins, T. C., and W. C. Bridges, Jr. 2007. Protection of fatty acids against ruminal biohydrogenation in cattle. Eur. J. Lipid Sci. Tech. 109:778-789 (Invited Review).
- Fievez, V., B. Vlaeminck, T. Jenkins, F. Enjalbert, and M. Doreau. 2007. Assessing rumen biohydrogenation and its manipulation in vivo, in vitro and in situ. Eur. J. Lipid Sci. Tech. 109:740-746 (Invited Review).
- Vazquez-Anon, M., G. Bowman, T. Hampton, P. Vazquez, T. Jenkins, and J. Nocek. 2007. Effects of feeding fresh and oxidized fat in the presence and absence of antioxidant on lactation performance. J. Dairy Sci. (Suppl. 1) 90:658.
- Y-J Lee, J. T. Brenna, P. Lawrence, S. K. Duckett, G. L. Powell, W. C. Bridges, Jr., and T. C. Jenkins. 2007. Identification of enriched conjugated linoleic acid isomers in cultures of ruminal microorganisms after dosing with 1-13C-linoleic acid. (Suppl. 1) 90: 659.
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Progress 01/01/06 to 12/31/06
Outputs
Most published accounts of linoleic acid biohydrogenation by ruminal microorganisms account for only a single C18:2 intermediate, namely the cis-9, trans-11 conjugated linoleic acid (CLA) isomer, prior to its complete hydrogenation to stearic acid. Recently, a trans-10, cis-12 CLA intermediate has been suggested. The purpose of this study was to determine the full range of C18:2 intermediates arising from the biohydrogenation of linoleic acid. Six rumen in vitro cultures were run that contained ground dairy feed (with 5% added unsaturated fatty acids), buffer, and strained rumen fluid from a ruminally-fistulated dairy cow. Half of the cultures received an additional 25 mg of unlabelled linoleic acid in 1 mL of ethanol and the other half received 25 mg U-13C-linoleic acid in ethanol injected at the start of incubation. Samples were taken from each flask at 0, 6, 24, and 48 hours. Methyl esters of fatty acids were separated on a 100-m CP-Sil 88 column and abundances of
the quasimolecular ion (M) and M+18 ion were determined by mass spectroscopy in positive chemical ionization mode. Enrichment (M+18/M minus background) of linoleic acid in the culture contents at 0 h was 0.32, which increased to 1.29 (P < 0.05) by 48 h. Enrichments at 48 h were 0.06 and 0.22 for stearic acid and cis-9, trans-11 CLA, respectively. Higher enrichments were observed for the trans-10, cis-12 CLA (1.33) and trans-9, trans-11 CLA (1.12) isomers by 48 h. Two additional peaks in the CLA region were enriched (0.99 and 0.87) but structural identification was not complete. The increasing enrichment of linoleic acid over time suggests preferential utilization of the unlabelled compound for biohydrogenation, which was consistent with low enrichment for stearic acid. High enrichments that increase over time, such as those seen for several CLA, might indicate conversion from the labeled linoleic acid via a nonenzymatic isomerization process. This project was supported by National
Research Initiative Competitive Grant no. 2005-35206-15426 from the USDA Cooperative State Research, Education, and Extension Service.
Impacts
Studies completed this year reveal the limitations of using excessive labeling of fatty acyl chains with carbon-13 in metabolic tracer studies involving ruminal microorganisms. Future isotope studies can utilize this information to increase the success of identifying key ateps in the biohydrogenation of polyunsaturated fatty acids.
Publications
- Jenkins, T. C. 2006. Rendered products in ruminant nutrition. In Essential Rendering, D. L. Meeker (Ed.), National Renderers Association, Alexandria, Virginia (Book Chapter)
- Teter, B. B., and T. C. Jenkins. 2006. Conjugated linoleic acid synthesis within the gut microbial ecosystem of ruminants. In Advances in Conjugated Linoleic Acid Research, Vol. 3, Martin P. Yurawecz, John K.G. Kramer, Ola Gudmundsen, Michael W. Pariza, and Sabastiano Banni (ed). AOCS Press, Champaign, Illinois (Book Chapter).
- Jenkins, T. C. and M. A. McQuire. 2006. Major advances in nutrition:Impact on milk composition. J. Dairy Sci. 89:1302-1310. (Invited Review)
- Gehman, A. M., J. A. Bertrand, T. C. Jenkins, and B. W. Pinkerton. 2006. The effect of carbohydrate source on nitrogen capture in dairy cows on pasture. J. Dairy Sci. 89:2659-2667.
- Mosley, E. E., A. Nudda, A. Corato, E. Rossi, T. Jenkins, and M.A. McGuire. 2006. Differential biohydrogenation and isomerization of [U-13C] oleic acid and [1-13C] oleic acids by mixed ruminal microbes. Lipids 41:513-517.
- Bilby, T. R., T. Jenkins, C. R. Staples, and W. W. Thatcher. 2006. Pregnancy, Bovine Somatotropin, and Dietary n-3 Fatty Acids in Lactating Dairy Cows: III. Fatty Acid Distribution. J. Dairy Sci. 89:3386-3399.
- Jenkins, T. C., A. A. AbuGhazaleh, S. Freeman, and E. J. Thies. 2006. The production of 10-hydroxystearic acid and 10-ketostearic acids is an alternate route of oleic acid transformation by the ruminal microbiota in cattle. J. Nutr. 136:926-931.
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Progress 01/01/05 to 12/31/05
Outputs
The formation of hydroxystearic acid (HSA) and ketostearic acid (KSA) from oleic acid transformation has been documented in a variety of microbial species, including several isolated from the rumen of domesticated ruminant species. However, their ruminal production rates have not been established as influenced by fatty acid source. Dosing continuous cultures of mixed ruminal microorganisms with 1-13C-oleic acid led to increased 13C enrichment of both HSA and KSA at 24 hours post-dosing, and showed that the majority (96 and 85%, respectively) of the HSA and KSA present in the 24 h samples originated from oleic acid. Several experiments using batch cultures of ruminal microorganisms showed that production of HSA and KSA was directly related to oleic acid input but not affected by elaidic acid input, and that HSA was further metabolized to KSA but not metabolized to other fatty acids. When continuous cultures of ruminal microorganisms were supplemented with soybean oil
or canola oil, production of 10-HSA + 10-KSA was related to oleic acid input but not to linoleic acid input. Daily production of 10-HSA + 10-KSA across treatments was 14.4 umol per 100 umol oleic acid input into the cultures or 31.1 umol per 100 umol oleic acid net loss. The results of this study quantify the formation of 10-HSA and 10-KSA from oleic acid transformation by ruminal microorganisms, and show that their accumulation in ruminal contents is directly related to the extent of oleic acid input and biotransformation by the rumen microbiota. Other studies were done to investigate a novel method for protecting FA by their containment within porcine-based protein capsules treated with hydroalcoholic solutions of formaldehyde. The treatment consists of washing capsules in 5% formaldehyde solution, rinsing in ethanol and drying. Protection was assessed by placing capsules in nylon bags, incubating in cultures of mixed ruminal microorganisms for 24 hours, and then analyzing for FA
content by gas chromatography. The capsules (n=10) were loaded with 59 mg of a conjugated linoleic acid (CLA) supplement containing 12.3 % oleic acid, and 74.2 % total CLA consisting of three isomers; (A) 36 % cis-9, trans-11, (B) 35.7 % trans-10, cis-12, and (C) 2.54 % trans-9, trans-11. Treated capsules (n=5) were still intact after incubation (opposed to untreated) with an average weight loss of 4.0 %. After incubation, the capsules (n=25) contained similar oleic acid (12.4 %) and total CLA (69.7 %) concentrations as before incubation. This study showed that formaldehyde-treated protein capsules substantially reduced FA loss due to biohydrogenation.
Impacts
Results from this project expand the pathways of oleic acid biohydrogenation by ruminal microorganisms to include two stearic acid derivatives that can be found in stomach contents of cattle, and potentially could enter the human food supply through meat and milk consumption. A novel form of protected fat also is proposed to avoid biohydrogenation and increase the tissue delivery of unsaturated fatty acids.
Publications
- AbuGhazaleh, A. A., M. B. Riley, E. E. Thies, and T. C. Jenkins. 2005. Dilution rate and pH effects on the conversion of oleic acid to trans C18:1 positional isomers in continuous culture. J. Dairy Sci. 88:4334-4341.
- Myers. P. J., S. E. Ellis, K.J.L. Burg, and T. C. Jenkins. 2005. Use of formaldehyde-treated protein capsules as a means to protect conjugated linoleic acid from ruminal biohydrogenation. J. Dairy Sci. (Suppl. 1): 83:97.
- Jenkins, T. C., A. A. AbuGhazaleh, E. J. Thies, and M. B. Riley. 2005. Conversion of oleic acid to 10-hydroxy and 10-keto stearic acids in vitro and their accumulation in milk of cows fed added fat. J. Dairy Sci. (Suppl. 1):371.
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Progress 01/01/04 to 12/31/04
Outputs
Project began October 1, 2004. No accomplishments to date.
Impacts
No impact to date
Publications
- No publications reported this period
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