New strategies for the protection of polyunsaturated fatty acids from the rumen microbiome

Funder

Organizational Unit

Publications

Freeze‑dried Nannochloropsis oceanica biomass protects eicosapentaenoic acid (EPA) from metabolization in the rumen of lambs

Publication . Vitor, Ana C. M.; Francisco, Alexandra Eduarda; Silva, Joana; Pinho, Mário; Huws, Sharon A.; Santos-Silva, José; Bessa, R.J.B.; Alves, Susana P.

Eicosapentaenoic acid (EPA) from freeze-dried biomass of Nannochloropsis oceanica microalgae resists ruminal biohydrogenation in vitro, but in vivo demonstration is needed. Therefore, the present study was designed to test the rumen protective effects of N. oceanica in lambs. Twenty-eight lambs were assigned to one of four diets: Control (C); and C diets supplemented with: 1.2% Nannochloropsis sp. oil (O); 12.3% spray-dried N. oceanica (SD); or 9.2% N. oceanica (FD), to achieve 3 g EPA /kg dry matter. Lambs were slaughtered after 3 weeks and digestive contents and ruminal wall samples were collected. EPA concentration in the rumen of lambs fed FD was about 50% higher than lambs fed SD or O diets. Nevertheless, the high levels of EPA in cecum and faeces of animals fed N. oceanica biomass, independently of the drying method, suggests that EPA was not completely released and absorbed in the small intestine. Furthermore, supplementation with EPA sources also affected the ruminal biohydrogenation of C18 fatty acids, mitigating the shift from the t10 biohydrogenation pathways to the t11 pathways compared to the Control diet. Overall, our results demonstrate that FD N. oceanica biomass is a natural rumen-protected source of EPA to ruminants.

2021-11-08Journal article

Open access

Strategies for the protection of Eicosapentaenoic acid (EPA) from the ovine rumen microbiota using Nannochloropsis oceanica

Publication . Vítor, Ana Cristina Martins de Miranda; Bessa, Rui José Branquinho de; Alves, Susana Paula Almeida; Huws, Sharon Ann

Marine oils derived from microalgae are a rich source of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) for ruminants, with several productivity and environmental advantages over fish oil. Nannochloropsis oceanica is a single-celled marine microalga particularly rich in eicosapentaenoic acid (EPA). N. oceanica slurry biomass can be dried using different methods, having different impacts in the ability to preserve EPA in its interior. The aim of this thesis was to explore the in vivo EPA ruminal protection degree and tissues deposition in lambs that were fed diets supplemented with different N. oceanica dried biomasses. Scanning electron microscopy confirmed that N. oceanica cells in freeze-dried biomass were better preserved than in spray-dried biomass. In the rumen, the estimates of biohydrogenation extent (disappearance) of EPA also confirmed that freeze dried N. oceanica was more protected from biohydrogenation. A lower t10/t11-18:1 ratio was observed in animals fed N. oceanica compared to animals fed the control diet. Overall, no disturbances were found in fermentable parameters nor indicators of ruminal parakeratosis. Microbiome analysis revealed that t10-18:1 may be a more suitable indicator compared to t11-18:1, for determining specific bacteriome profiles in the rumen. Incorporating N. oceanica into the diets resulted in a higher content of n-3 LC PUFA in the meat and subcutaneous adipose tissue of the supplemented lambs, with EPA being the most significant contributor. It was also possible to conclude that brain EPA content was not responsive to dietary supplementation. However, the retina showed a significant response in lambs supplemented with N. oceanica. A novel ruminal-resistant n-3 LC-PUFA encapsulation method using N. oceanica extracted algaenan was developed and tested in vitro with yet inconclusive results regarding the protection of EPA

2023-10-18Doctoral thesis

Open access