Wild Herb Feed Additive Fails to Boost Broiler Growth but Shakes Up Antioxidant Bloodmarks

A wild medicinal plant from the mountains of western Iran has put a new spin on one of poultry science’s most persistent quests: finding a natural replacement for antibiotic growth promoters. In a carefully controlled 43-day feeding trial, researchers at the University of Kurdistan tested whether Prangos ferulacea, an aromatic member of the carrot family prized in traditional West Asian medicine, could improve growth, carcass quality, and antioxidant defenses in fast-growing broiler chickens. The verdict, published in the journal Discover Animals, is a nuanced one. The plant did not make the birds grow faster or convert feed more efficiently, but it did leave measurable fingerprints on their blood chemistry and liver antioxidant machinery — and some of those fingerprints raise as many questions as they answer.

The trial involved 300 one-day-old male Cobb 500 broiler chicks, randomly assigned to five dietary treatments with four replicate pens of 15 birds each. One group received a standard corn–soybean meal control diet, while the others were fed diets supplemented with either 0.75 percent or 1.5 percent Prangos ferulacea powder, or with 750 or 1500 milligrams per kilogram of the plant’s aqueous extract. All diets were formulated to be isocaloric and isonitrogenous, meaning they delivered equivalent levels of energy and protein, so any differences between groups could be attributed to the plant material itself rather than to nutritional imbalances. The birds were monitored over a full 43-day production cycle spanning starter, grower, and finisher phases.

The plant material itself carried considerable biochemical promise. Prangos ferulacea is native to West Asia and is rich in monoterpenes, coumarins, and phenolic compounds — classes of molecules frequently associated with antioxidant, antimicrobial, and smooth-muscle-modulating activity. The researchers harvested mature aerial parts of the plant from the rangelands of Divandareh County in Kurdistan Province, shade-dried them, and milled them into powder. To prepare the aqueous extract, ten kilograms of powder were macerated in thirty liters of distilled water for twenty-four hours, filtered, and concentrated at sixty to seventy degrees Celsius, yielding roughly 10.8 percent of the starting weight as dried extract. Botanical identity was confirmed by a qualified botanist, and a voucher specimen was deposited in the university herbarium, lending the study a level of taxonomic rigor that is not always present in phytogenic feed research.

When it came to the bottom line of broiler production — body weight gain and feed conversion ratio — the results were sobering. Across the entire 43-day period, cumulative body weight gain and feed efficiency did not differ significantly among the five dietary groups. Body weights at eleven, twenty-three, and forty-three days of age were statistically indistinguishable. There was, however, a phase-specific wrinkle: during the finisher period from days twenty-four to forty-three, body weight gain was significantly reduced in the supplemented groups compared with the control, a pattern the authors suggest could relate to effects on feed intake or palatability, though the underlying cause was not directly measured. Feed intake during the grower phase was actually higher in all supplemented groups, yet this did not translate into better growth, and overall feed intake across the trial was unaffected.

Carcass characteristics told a similarly restrained story. Carcass yield and the relative weights of the heart, liver, spleen, pancreas, and bursa of Fabricius were comparable across treatments. One exception stood out: birds fed the lower dose of the powder, 0.75 percent of the diet, showed a significantly heavier gizzard relative to their body weight than both extract-fed groups and the control. The authors speculate that the fibrous, structural nature of the powdered plant material may have stimulated gizzard development, a phenomenon previously reported with coarse or fiber-rich feed components, but they caution that because particle size was not measured, this interpretation remains speculative.

Blood chemistry offered a few more points of interest. Serum triglycerides were significantly lower in birds receiving 0.75 percent powder, while very-low-density lipoprotein levels were unchanged, suggesting the plant does not exert a broad effect on lipid metabolism. Serum cholesterol was significantly lower in birds receiving both forms of supplementation compared with controls, and markers of kidney function — urea, creatinine, and uric acid — were unaffected, indicating the treatments were not harming the birds. Total protein, albumin, and globulin concentrations also remained stable, painting a picture of animals whose basic metabolic health was intact regardless of diet.

The most intriguing and, frankly, most puzzling findings emerged from the antioxidant measurements. Birds receiving the highest dose of aqueous extract, 1500 milligrams per kilogram, showed a significant increase in serum total antioxidant capacity, a measure of the blood’s non-enzymatic antioxidant potential. That might sound like a win for the plant. But the same group also exhibited significantly elevated serum malondialdehyde, a well-established marker of lipid peroxidation and oxidative damage, alongside significantly reduced glutathione peroxidase activity in the liver, one of the body’s key antioxidant enzymes. In fact, all four supplemented groups showed reduced hepatic glutathione peroxidase activity compared with controls, while liver superoxide dismutase showed only a trend toward reduction and red blood cell enzyme activities were unchanged.

This pattern — higher total antioxidant capacity coexisting with more lipid damage and less enzymatic defense — does not add up to an unequivocal antioxidant benefit, and the authors are careful to say so. Rather, they argue, it points to a complex and potentially pro-oxidant response at the highest extract dose, consistent with the dose-dependent or biphasic effects that phytochemicals sometimes display. It also underscores a broader lesson for the field: antioxidant biomarkers should be interpreted collectively rather than in isolation, and a shift in any single indicator does not necessarily signal improved health. Notably, none of the biochemical changes translated into better growth, feed efficiency, or carcass yield, reinforcing a growing consensus that modulating redox biomarkers under low-stress conditions may not produce tangible production benefits.

The study has honest limitations that shape how its findings should be read. With only four replicate pens per treatment and one bird per pen sampled for biochemical analyses, statistical power to detect subtle effects was limited. The experimental diets were formulated on calculated rather than chemically analyzed nutrient values, and the phytochemical characterization relied on spectrophotometric assays of total phenolics, flavonoids, and coumarins rather than chromatographic identification of individual compounds — meaning the differences between powder and extract cannot be tied to specific active constituents or their bioavailability. The authors also note that under the non-stressed conditions of a well-managed research facility, the birds’ endogenous antioxidant systems may already have been operating near optimal levels, leaving little room for a phytogenic additive to demonstrate measurable gains.

Where does this leave Prangos ferulacea on the crowded shelf of candidate antibiotic alternatives? The study contributes to mounting evidence that phytogenic feed additives can shift oxidative status without necessarily improving performance, particularly in animals that are not under environmental or metabolic stress. The authors chart a clear path forward: comprehensive phytochemical profiling of the plant, formal dose–response studies, investigation of molecular mechanisms such as redox-sensitive signaling pathways like Nrf2, and — perhaps most importantly — testing under oxidative-stress challenge models that better mirror the realities of commercial poultry production. Until then, the mountain herb remains a biochemical curiosity with demonstrated biological activity but, at the doses and conditions tested, no proven ticket to faster-growing, healthier chickens. For an industry under pressure to eliminate antibiotics, that distinction between biochemical activity and production benefit is exactly the kind of hard evidence that keeps the search honest.

Subject of Research: Effects of dietary Prangos ferulacea powder and aqueous extract on growth performance, carcass traits, and antioxidant status in broiler chickens

Article Title: Effects of different levels of Prangos ferulacea (L.) Lindl. (Apiaceae) powder and extract on performance, carcass characteristics, and antioxidant status in broiler chickens

Article References: Janfadah, A., Sadeghi, A. A., & Karimi, A. (2026). Effects of different levels of Prangos ferulacea (L.) Lindl. (Apiaceae) powder and extract on performance, carcass characteristics, and antioxidant status in broiler chickens. Discover Animals, 3(1), Article 98. https://doi.org/10.1007/s44338-026-00250-7

Image Credits: AI Generated

DOI: 10.1007/s44338-026-00250-7

Keywords: Prangos ferulacea, broiler chickens, phytogenic feed additives, antioxidant status, total antioxidant capacity, malondialdehyde, glutathione peroxidase, feed conversion ratio, carcass characteristics, poultry nutrition, antibiotic alternatives, oxidative stress