New research from Teagasc has explored the possibility of using by-products from seaweed as a sustainable source of pig feed.

The research was carried out under an EU Horizon Europe project called CIRCALGAE, and saw researchers at the Teagasc Pig Development Department investigate whether ingredients produced from seaweed processing can provide a sustainable alternative feed ingredient for use in pig diets.

The research was conducted by a project team led by Teagasc's Prof. Peadar Lawlor and including Dr. Clara Negrini, Joe Glynn and Dr. Linda Giblin, as well as Prof. Gillian Gardiner from South-East Technological University (SETU).

Following the extraction of high value products (e.g., agar, phycocyanin) from seaweed, a substantial residue remains.

Instead of treating this as a waste product, CIRCALGAE explored how it can be further processed so that it is suitable for use as a feed ingredient in pig diets.

According to Teagasc, this approach supports the principles of the circular bioeconomy by reducing waste and creating new, high-value feed ingredients from existing resources.

The research focused on feeding these "revalorised" seaweed-derived ingredients during the post-weaning period, as during this stage of production pigs are particularly vulnerable to digestive disorders and reduced feed intake.

As seaweed often contains significant levels of bioactive compounds, its dietary inclusion could be particularly beneficial during this stage of production, the researchers said.

Findings

Across a series of feeding trials, four revalorised seaweed-derived ingredients were evaluated for their effects on animal growth performance and intestinal health.

In addition to measuring pig growth, intestinal structure and function; blood parameters and intestinal microbiota were examined to understand how these ingredients interact with the animal.

The studies found that dietary inclusion of the selected seaweed-derived ingredients at levels between 1% and 5%, when substituted for conventional feed ingredients, maintained pig growth and health.

Some of the seaweed-derived ingredients improved feed efficiency during the early post-weaning period, while others promoted changes in intestinal structure, gut barrier function or modulated intestinal microbial composition.

The research was carried out in collaboration with research partners across Europe, combining expertise across different fields.

The CIRCALGAE research project is now entering its final phase.

Teagasc said the knowledge generated will help guide the future development of sustainable feed ingredients derived from marine resources and "contribute to more resilient and resource efficient pig production systems".