**5. Conclusions**

In conclusion, while it was hypothesized that both LAM and FUC extracts would have a beneficial impact on performance and intestinal health out to day 35 post-weaning, only the supplementation of LAM was beneficial on intestinal health, with no identifiable effect on performance. Further research will need to be conducted to assess the long-term impact of the feeding the LAM extract in unsanitary/challenge conditions, but also for inclusion in human studies due to its positive impact on the intestinal microbiome.

**Supplementary Materials:** The following are available online at https://www.mdpi.com/article/10 .3390/md19040183/s1, Table S1: Differential abundance analysis of bacterial taxa at phylum level in colonic digesta, Table S2: Differential abundance analysis of bacterial taxa at family level in colonic digesta, Table S3: Differential abundance analysis of bacterial taxa at genus level in colonic digesta, Table S4: Effect of laminarin or fucoidan inclusion on the expression of nutrient transporters and immune markers in the duodenum, Table S5: Effect of laminarin or fucoidan inclusion on the expression of nutrient transporters and immune markers in the jejunum, Table S6: Effect of laminarin or fucoidan inclusion on the expression of nutrient transporters and immune markers in the ileum.

**Author Contributions:** Conceptualization, J.O. and T.S.; Methodology, R.R.; Formal analysis, S.V.; Investigation, S.V.; Data curation, R.R. and S.V.; Writing—original draft preparation, S.V.; Writing— review and editing, S.V., J.O. and T.S.; Funding acquisition, J.O. and T.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Science Foundation Ireland, gran<sup>t</sup> no. 14/IA/2548.

**Institutional Review Board Statement:** All experimental procedures described in this work were approved under the University College Dublin Animal Research Ethics Committee (AREC-17-19- O'Doherty, 11 May 2017) and were conducted in accordance with Irish legislation (SI no. 543/2012) and the EU directive 2010/63/EU for animal experimentation.

**Informed Consent Statement:** Not applicable. **Conflicts of Interest:** The authors declare no conflict of interest.
