Study links glucosamine to better shell quality in aged hens: full analysis

A March 2026 paper in Animals adds glucosamine to the growing list of feed additives being tested to support older laying hens. In a 4-week experiment involving 144 aged hens, researchers reported that dietary glucosamine improved laying rate, eggshell strength, eggshell thickness, and feed efficiency, while the higher-dose group also showed better liver-related biochemical and antioxidant indicators. (agris.fao.org)

The study lands in a part of poultry production where losses can add up quickly. As hens age, shell quality often deteriorates, breakage risk rises, and metabolic strain becomes more visible, including fatty liver changes and weaker antioxidant defenses. Recent work has explored a wide range of interventions, from altered light cycles and probiotics to trace minerals and plant-derived compounds, all aimed at extending productive life without sacrificing egg quality. One recent example is α-mangostin, a xanthone from mangosteen pericarp: in a separate 4-week Animals study in 576 51-week-old hens, 120 mg/kg improved feed efficiency from week 2 onward and increased egg weight and eggshell strength, while also enhancing antioxidant status and lowering uterine and serum interleukin-1β. (mdpi.com)

According to the article record, the glucosamine trial compared a control diet with 0.15% and 0.35% glucosamine inclusion levels. The authors reported significant gains in laying rate, eggshell strength, and eggshell thickness, along with a reduced feed-to-egg ratio. In the 0.35% group, serum AST, triglycerides, and malondialdehyde decreased, while albumin and glutathione peroxidase increased, findings the authors interpreted as evidence of improved liver health and antioxidant capacity. (agris.fao.org)

The mechanistic angle may be what draws the most attention from poultry veterinarians and nutrition teams. The researchers said glucosamine upregulated hepatic genes tied to fatty acid oxidation and antioxidant defense, including PPARA, ACOX1, GSTT1, and CAT, while downregulating genes associated with fatty acid synthesis and inflammation, including PPARG, FASN, TGFBR2, and TNF-α. They also reported increased expression of uterine eggshell matrix protein genes, suggesting a possible dual effect on liver metabolism and shell formation. That dual-pathway idea also appears in the α-mangostin literature: the 120 mg/kg group in the separate aging-hen study upregulated uterine genes involved in calcium transport and biomineralization, including TRPV6, ATP2B2, OC-116, LYZ, CA2, SLC4A9, and ATP6V0D2, alongside lower inflammatory signaling. (agris.fao.org)

Outside reaction specific to this paper was limited in the sources available, but the broader research environment supports interest in this kind of intervention. Other recent studies in aged or late-phase laying hens have linked improved shell quality or production to interventions affecting calcium handling, uterine health, microbiota, oxidative stress, and liver lipid metabolism. A 2024 Poultry Science study found glucosamine sulfate sodium improved early laying performance and eggshell-related outcomes in younger hens, which gives this new aged-hen paper some biological continuity, even though the populations and dosing schemes differ. The α-mangostin findings add another point of comparison by suggesting that antioxidant and anti-inflammatory support at the uterine level may also translate into stronger shells, even when egg production rate itself does not change. (sciencedirect.com)

Why it matters: For veterinary professionals working with commercial layers, the appeal here is practical: one additive that may improve shell quality, feed conversion, and liver health in older birds. That matters because late-lay management is rarely about a single endpoint. Shell breakage, fatty liver risk, oxidative stress, and reduced persistence of lay often show up together, and they affect both welfare and economics. The glucosamine paper is especially interesting because it points to both hepatic and uterine mechanisms, while the α-mangostin study suggests a parallel route centered on antioxidant defense, reduced oviduct inflammation, and improved expression of shell-formation genes. If glucosamine’s effects hold up in larger and longer trials, it could become part of a broader nutritional strategy for extending flock productivity. But this is still early evidence, and the study’s short duration, limited sample size, and single-publication status mean it should be read as promising, not practice-changing. (agris.fao.org)

There are also some important caveats. The article is published in MDPI’s Animals, and while that provides rapid access to the findings, veterinarians and nutritionists will still want to see independent replication, fuller economic modeling, and comparisons against established interventions such as calcium-source optimization, trace mineral adjustments, probiotics, or lighting strategies. It will also matter whether benefits persist beyond four weeks and whether they translate cleanly across breeds, housing systems, and commercial feed programs. Comparisons with other emerging additives, including plant-derived compounds such as α-mangostin, could help clarify whether the main advantage lies in metabolic support, uterine anti-inflammatory effects, or some combination of both. (mdpi.com)

What to watch: The next step is whether follow-on studies test glucosamine in commercial late-lay settings, over longer feeding periods, and against other nutrition tools already being evaluated for shell quality and hepatic support in aging hens, including additives that target uterine inflammation, antioxidant capacity, and calcium transport pathways. (sciencedirect.com)