Seaweed polysaccharide shows promise against aged-maize stress in sheep
Bottom line
A pair of recent Animals studies adds to the evidence that Laminaria japonica polysaccharide, or LJP, may help offset some of the downsides of feeding aged corn or maize to Hu sheep. In one trial, sheep fed aged corn had poorer growth performance, nutrient digestibility, rumen fermentation measures, and muscle antioxidant status than animals fed normal corn, while adding 0.5% LJP to the aged-corn diet improved several of those outcomes. A second study extended that picture beyond performance, reporting that LJP supplementation in sheep fed aged maize was associated with lower intestinal oxidative stress and systemic inflammation, alongside shifts in the cecal microbiome and metabolome. Both papers were published in Animals and build on broader research suggesting seaweed-derived polysaccharides can act as antioxidant, immunomodulatory, and microbiota-active feed ingredients. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals working with small ruminants and production systems, the findings are less about a ready-to-use intervention and more about a familiar risk: feed quality deterioration during storage can affect animal health well before overt clinical disease appears. These papers point to oxidative stress, gut barrier effects, and inflammatory signaling as part of the biological cost of aged maize feeding, and they suggest one possible nutritional mitigation strategy. Still, the evidence comes from small, controlled studies in Hu sheep, and broader questions around reproducibility, economics, formulation, ingredient consistency, and regulatory fit remain open. Reviews of seaweed use in livestock also note practical constraints, including variable composition, mineral load, and supply-chain standardization. (ahdb.org.uk)
What to watch: The next step is whether these findings are replicated in larger commercial flocks, other ruminant species, and real-world feed programs, with clearer data on dose, cost, safety, and product standardization. (sciencedirect.com)
Two related papers in Animals are sharpening the picture of what happens when sheep are fed long-stored maize, and what might help. The studies report that Laminaria japonica polysaccharide, a seaweed-derived feed additive, improved multiple health and performance markers in Hu sheep fed aged corn or maize, including growth-related outcomes in one paper and intestinal oxidative stress and systemic inflammation in the other. Together, they frame aged grain not just as a nutritional quality issue, but as a gut-health and inflammatory challenge. (pubmed.ncbi.nlm.nih.gov)
That matters because long-term grain storage can reduce feed value, and in ruminant systems, even modest declines in ingredient quality can ripple through intake, digestibility, fermentation, and downstream health. The source studies focus on Hu sheep, a common research and production breed in China, and fit into a wider body of work examining how diet composition changes rumen and hindgut biology in this species. Recent Hu sheep research has also linked diet interventions to microbiota shifts, inflammatory changes, and performance differences, underscoring how tightly feed quality and gut physiology are connected. (ahdb.org.uk)
In the first study, 21 male Hu sheep were assigned to normal-corn, aged-corn, or aged-corn-plus-LJP diets for 70 days, with seven animals per group, according to the paper summary provided in the source material. The aged-corn diet reduced average daily gain, feed efficiency, apparent digestibility, and some antioxidant-related measures compared with normal corn, while 0.5% LJP supplementation improved several of those parameters. The second paper examined a different layer of the same problem, reporting that LJP supplementation alleviated aged-maize-associated intestinal oxidative stress and systemic inflammation, with accompanying remodeling of the cecal microbiome and metabolome. While the full mechanistic details of that paper weren’t accessible through direct page retrieval during research, the study’s abstract-level findings align with broader literature describing LJP as antioxidant, anti-inflammatory, and microbiota-modulating. (pubmed.ncbi.nlm.nih.gov)
That biological plausibility is important. PubMed-indexed and review literature describe Laminaria japonica polysaccharides as bioactive compounds with prebiotic and immunomodulatory effects, and recent work in other models has tied them to gut microbiota remodeling and barrier support. Separate 2026 research in Hu sheep found that dietary exopolysaccharides reduced colonic dysfunction, oxidative stress, and inflammatory signaling under a high-concentrate feeding challenge, which doesn’t prove the same mechanism here, but does support the broader idea that polysaccharide-based additives can influence hindgut resilience in sheep. That’s an inference from adjacent evidence, not a direct validation of the aged-maize study. (pubs.acs.org)
No major independent veterinary association statement or company announcement tied to these specific papers surfaced in the search results, which suggests this is still an early research story rather than a market-moving one. Industry and academic reviews of seaweed use in livestock are generally cautiously positive: they highlight potential benefits for antioxidant status, gut health, and performance, but they also repeatedly flag variability in seaweed composition, processing methods, mineral content, and practical inclusion limits. Some reviews also note safety and residue questions for certain seaweed applications in ruminants, especially when products are scaled commercially. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For veterinarians, nutritionists, and flock advisers, the takeaway isn’t that pet parents should expect seaweed supplements to enter routine sheep feeding tomorrow. It’s that feed storage quality deserves closer attention as a health variable, and that nutritional mitigation strategies may eventually complement management fixes. If aged maize contributes to oxidative stress, inflammatory signaling, and microbiome disruption before obvious production losses become severe, then surveillance of feed condition, ration consistency, and subtle health markers becomes more relevant. The studies also reinforce a broader veterinary nutrition trend: additives are increasingly being evaluated not only for growth or feed conversion, but for effects on gut integrity, redox balance, and systemic inflammation. (ahdb.org.uk)
There are still important limits. The trials appear small, species- and breed-specific, and conducted under controlled conditions. The journal is a legitimate, indexed outlet, but these findings still need replication, clearer economic analysis, and more transparency on ingredient characterization before they can support broad on-farm recommendations. It will also matter whether future work tests LJP against other antioxidant or functional fiber strategies, and whether benefits hold when storage-related feed damage is less pronounced than in an experimental model. (mdpi.com)
What to watch: Watch for follow-up studies in larger flocks, dose-response work, and any commercial or regulatory movement around standardized seaweed-polysaccharide feed additives for ruminants, especially data that connect lab biomarkers to production outcomes and cost of use. (sciencedirect.com)
Common questions
What did the studies find about aged corn or maize in sheep diets?
Sheep fed aged corn or maize had poorer growth, digestibility, rumen fermentation, and antioxidant status, along with higher intestinal oxidative stress and systemic inflammation.Did Laminaria japonica polysaccharide help?
Yes. Adding 0.5% LJP to the aged-corn diet improved several growth and digestibility measures, and in the aged-maize study it was associated with lower oxidative stress and inflammation.What kind of sheep were studied?
Hu sheep.Are these findings ready for routine on-farm use?
No. The article says the evidence comes from small, controlled studies, and broader questions about reproducibility, economics, formulation, ingredient consistency, safety, and regulatory fit remain open.