Immunogenic inhibition of prominent ruminal bacteria as a means to reduce lipolysis and biohydrogenation activity in vitro

Authors: EDWARDS, HOLLY - Texas A&M University; Shelver, Weilin; CHOI, SEONGHO - Chungbuk National University; Nisbet, David; Krueger, Nathan; Anderson, Robin; SMITH, STEPHEN - Texas A&M University

Submitted to: Journal of Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/7/2016
Publication Date: 3/1/2017
Citation: Edwards, H.D., Shelver, W.L., Choi, S., Nisbet, D.J., Krueger, N.A., Anderson, R.C., Smith, S.B. 2017. Immunogenic inhibition of prominent ruminal bacteria as a means to reduce lipolysis and biohydrogenation activity in vitro. Journal of Food Chemistry. 218:372-377.

Interpretive Summary: Bacteria present in the stomach of cows, sheep, and goats convert nearly all the unsaturated fat these animals eat into saturated fat. Because natural sources of unsaturated fats are considered to be protective against bacterial infections in the stomach of cows, sheep, and goats and to be healthier for humans, we conducted a study to see if we could develop a technology to protect these healthy unsaturated fats in the cow, sheep, and goat stomachs. Antibodies were generated against the stomach bacteria responsible for converting the unsaturated fats to saturated fats and tested in the laboratory to see if these would inhibit that process. We found that the antibodies did indeed prevent bacterial conversion of the unsaturated fats. These results provide important evidence that can be used to aid the development of a new technology to help farmers and ranchers enhance the quality and microbiological safety of the meat and milk they produce.

Technical Abstract: Through the microbial processes of lipolysis and biohydrogenation, ruminal animals promote the accumulation of saturated fatty acids in their meat and milk. Anaerovibrio lipolyticus, Butyrivibrio fibrisolvens, and Propionibacterium avidum and acnes have been identified as contributors to ruminal lipolysis. Antibodies generated against these bacteria were tested as a means to inhibit lipolytic activity. An anti-Pseudomonas lipase antibody was tested to determine if an antibody raised against the purified protein would be more effective. Each bacterium was cultured and assayed with 0.3 mL olive oil without or with increasing levels of antibody (0.2, 1.0, 2.5, 5.0 mg protein). Each antibody was tested against each pure culture bacterium. Butyrivibrio fibrisolvens participates in both lipolysis and biohydrogenation processes, therefore, the anti-B. fibrisolvens H17C antibody was also tested to determine if it would be effective at reducing biohydrogenation against a pure culture of B. fibrisolvens H17C. Pure cultures were assayed without and with 5.0 mg of the anti-B. fibrisolvens antibody and 6 mg of linoleic (18:2n-6) or a-linolenic acid (18:3n-3). Lipolysis was measured by the accumulation of free fatty acids and biohydrogenation was determined by measuring fatty acid products. All five antibodies were effective at reducing lipolytic activity, with the anti- Pseudomonas lipase being the most effective, averaging almost a 78% reduction in lipolytic activity across all bacteria at the highest antibody dose. Biohydrogenation of a-linolenic acid also was depressed by the anti-Pseudomonas lipase up to 55% compared to controls. These results demonstrated that lipolysis and biohydrogenation can be immunologically inhibited in vitro.