Fermented grape seed shows mixed results in breeding pigeons

A newly published paper in Animals examined fermented grape seed as a feed additive in breeding pigeons and found a mixed, cautionary signal rather than a clear nutritional win. The study, published August 29, 2026, evaluated whether supplementing breeder diets with fermented grape seed could improve growth, immunity, and oxidative status in offspring squabs. Instead, the authors concluded that none of the tested inclusion levels could be considered optimal, and that the highest dose appeared excessive. (mdpi.com)

The idea behind the trial fits a broader feed-industry trend: finding productive uses for agricultural byproducts with potential bioactive value. Grape seed and other grape byproducts have drawn attention in poultry because they contain polyphenols and other compounds that may affect antioxidant status, gut health, immunity, and metabolism. At the same time, prior poultry research has shown those effects can vary sharply depending on dose, fermentation method, and the rest of the ration. Reviews and broiler studies have also noted that fermentation can change the bioavailability and biological activity of grape-derived compounds, without guaranteeing better performance in every setting. (pmc.ncbi.nlm.nih.gov)

In the pigeon study, 48 healthy pairs of Gray King breeding pigeons were assigned to one of four diets: control, or FGS at 10, 20, or 30 kg per 1,000 kg of basal diet. Breeders began the diets seven days before expected hatch, and each pair reared three squabs through 28 days of age. The researchers tracked growth performance, carcass traits, meat quality, serum biochemistry, immunoglobulins, inflammatory cytokines, and serum and hepatic redox markers. The strongest negative findings were in the highest-dose group. FGS30 reduced average daily gain from days 14 to 21 and 14 to 28, increased IgA, IgG, and IgM, raised interleukin-10 and TNF-α, increased AST and LDL cholesterol, and elevated serum and hepatic malondialdehyde while lowering hepatic superoxide dismutase and glutathione peroxidase activity. (mdpi.com)

The middle dose was not a clean success either. While FGS20 showed numerical advantages in some production traits, it also increased breast muscle lightness and press loss, and did not improve hepatic redox status. Importantly, the authors noted that the fermented grape seed product was added on top of the basal diet rather than substituted into a fully reformulated ration, so the experimental diets were not designed to be isonitrogenous or isoenergetic. That matters when interpreting whether observed effects came from the additive itself, from nutrient displacement, or from both. (mdpi.com)

There doesn’t appear to be a separate institutional press release or broad veterinary-industry reaction yet, which isn’t unusual for a niche production-avian nutrition paper published only days ago. Still, the findings line up with a familiar expert theme in avian nutrition: unconventional feed ingredients can be promising, but dose and formulation discipline matter. Merck’s veterinary guidance notes that pigeons and doves have specific nutritional needs and can be fed commercial pigeon pellets formulated to approximate established nutrient requirements, underscoring why add-on supplementation without full ration balancing deserves caution. (merckvetmanual.com)

Why it matters: For veterinarians, consulting nutritionists, and producers advising pet parents or commercial pigeon operations, this study is less about fermented grape seed specifically and more about how breeder diets can shape squab outcomes. Squabs rely on parental crop milk and then regurgitated feed, so any breeder-diet intervention has indirect effects on offspring physiology. That makes breeder supplementation attractive, but also risky if the additive changes inflammatory tone, oxidative balance, or nutrient density in ways that aren’t obvious from growth alone. In this case, higher FGS inclusion appeared to increase immune-related markers alongside signs of oxidative and metabolic strain, which is not the same as improved health. (merckvetmanual.com)

The paper also adds a useful note of restraint to the broader enthusiasm around grape byproducts in animal feed. Some broiler work has reported growth, microbiome, or antioxidant benefits from fermented grape seed meal, and recent academic coverage has highlighted grape-processing leftovers as a possible alternative to antibiotic-era production tools in poultry. But the pigeon data suggest species, production stage, parental transfer dynamics, and product formulation all matter. Results from broilers can’t simply be imported into breeder-pigeon systems. (pubmed.ncbi.nlm.nih.gov)

What to watch: The next step is likely validation in tighter dose ranges, especially below 30 kg/1,000 kg and possibly within the 10 to 20 kg/1,000 kg range the authors flagged for further study. It would also be useful to see trials with fully balanced diets, more detail on the fermented ingredient’s composition, and replication across other pigeon lines or production conditions before any practical recommendation is made. (mdpi.com)