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Background: Poor feather growth not only affects the appearance of the organism but also decreases the feed efficiency. Methionine (Met) is an essential amino acid required for feather follicle development; yet the exact mechanism involved remains insufficiently understood. Methods: A total of 180 1-day-old broilers were selected and randomly divided into 3 treatments: control group (0.45% Met), Met-deficiency group (0.25% Met), and Met-rescue group (0.45% Met in the pre-trial period and 0.25% Met in the post-trial period). The experimental period lasted for 56 d, with a pre-trial period of 1–28 d and a post-trial period of 29–56 d. In addition, Met-deficiency and Met-rescue models were constructed in feather follicle epidermal stem cell by controlling the supply of Met in the culture medium. Results: Dietary Met-deficiency significantly (P < 0.05) reduced the ADG, ADFI and F/G, and inhibited feather follicle development. Met supplementation significantly (P < 0.05) improved growth performance and the feather growth in broilers. Met-rescue may promote feather growth in broilers by activating the Wnt/β-catenin signaling pathway (GSK-3β, CK1, Axin1, β-catenin, Active β-catenin, TCF4, and Cyclin D1). Compared with Met-deficiency group, Met-rescue significantly (P < 0.05) increased the activity of feather follicle epidermal stem cell and mitochondrial membrane potential, activated Wnt/β-catenin signaling pathway, and decreased the content of reactive oxygen species (P < 0.05). CO-IP confirmed that mitochondrial protein PGAM5 interacted with Axin1, the scaffold protein of the disruption complex of the Wnt/β-catenin signaling pathway, and directly mediated Met regulation of Wnt/β-catenin signaling pathway and feather follicle development. Conclusions: PGAM5 binding to Axin1 mediates the regulation of Wnt/β-catenin signaling pathway, and promotes feather follicle development and feather growth of broiler chickens through Met supplementation. These results provide theoretical support for the improvement of economic value and production efficiency of broiler chickens. [ABSTRACT FROM AUTHOR]

The aim of this study was to isolate and characterize keratinolytic thermophilic aerobic bacilli from Armenian geothermal springs. In total 20 thermophilic aerobic bacilli strains have been isolated using chicken feather enrichment cultures. Among these, four strains affiliated (based on 16S rRNA genes sequences) as Bacillus licheniformis (95–97% similarity) and Bacillus borbori (> 99% similarity) demonstrated the capability to completely degrade chicken feathers at 55 °C. The highest rate of feather hydrolyses in mono-species cultures was observed with 40 g L−1 substrate. Notably, enhanced keratin weight loss (≥ 80%) was observed in dual co-cultures involving B. borbori M14, highlighting superior degradative potential of this strain. Keratinolytic enzyme production was dedected during the late exponential growth phase, reached its maximum activity (0.013 U mL−1) during the stationary phase, suggesting growth-associated enzyme synthesis. High-performance liquid chromatography (HPLC) of the hydrolysis end products revealed that aspartic acid and isoleucine were the predominant amino acids, followed by leucine, phenylalanine, alanine, tyrosine and glutamic acid. These findings confirm that the newly isolated strains are promising sources of keratinolytic proteases, with potential applications in circular bioeconomy based processes. [ABSTRACT FROM AUTHOR]

Simple Summary: Skin appendages, such as hair and feathers, are characteristic traits of mammals and birds, respectively. They are prototypes for a much broader range of skin appendages including also scales, claws, scutes and beaks, which develop in land-dwelling vertebrates. All these skin appendages have in common that they consist of dead cells which are tightly packed with specific proteins. This review provides an overview of the protein components of skin appendages characterized so far and identifies gaps of knowledge that need to be addressed by future studies. In particular, keratins and proteins encoded by genes of the so-called epidermal differentiation complex are highlighted as critical contributors to the architecture of feathers, scales and claws. As many skin appendage proteins have been predicted but not fully characterized yet with regard to their three-dimensional structure, interactions with other proteins and distribution in skin cells, they are important topics of ongoing research. Reptiles, birds, mammals and amphibians, together forming the clade tetrapods, have a large diversity of cornified skin appendages, such as scales, feathers, hair and claws. The skin appendages consist of dead epithelial cells that are tightly packed with specific structural proteins. Here, we review the molecular diversity and expression patterns of major types of skin appendage proteins, namely keratin intermediate filament proteins, keratin-associated proteins (KRTAPs) and proteins encoded by genes of the epidermal differentiation complex (EDC), including corneous beta-proteins, also known as beta-keratins. We summarize the current knowledge about the components of skin appendages with a focus on keratins and EDC proteins that have recently been identified in reptiles and birds. We discuss gaps of knowledge and suggest directions of future research. [ABSTRACT FROM AUTHOR]

This study demonstrated that feathers, primarily composed of keratin, can be converted into eco-friendly products using the newly isolated strain Chitinophaga eiseniae 4 H (C.eiseniae 4 H), which degrades puffed feather powder by over 90 % in 36 hours. The PFP degradation solution's surface tension dropped to 32.35 ± 0.096 mN/m after 60 hours, with inhibition zones of 12 mm and 14 mm observed for the 48-hour and 72-hour hydrolysates. Additionally, the concentrations of total amino acids and essential amino acids increased significantly after 24 hours of hydrolysis. This approach provides a novel strategy to utilize feather-containing waste for producing value-added biosurfactants with antibacterial and antioxidant properties. [Display omitted] • First discovery that C. eiseniae 4 H degrade puffed feather powder (PFP) efficiently. • First discovery that C. eiseniae 4 H biotransform PFP into biosurfactants. • First discovery that C. eiseniae 4 H biotransform PFP into antibacterial and antioxidant solution. [ABSTRACT FROM AUTHOR]

In this study, the surface of duck feather was modified with (3-chloropropyl) trimethoxysilane and (1,4-diazabicyclo[2.2.2]octane), and it was used as a natural polymeric adsorbent to remove nitrate ion from a solution. The prepared modified duck feather was characterized using TGA, FT-IR, and FE-SEM analyses. The study examined the effect of various parameters such as pH, contact time, adsorbent dosage, and initial concentration of nitrate on adsorption efficiency. pH = 7, 40 min contact time, 30 mg of adsorbent, and 40 mg/L initial concentration of nitrate were found as the optimum conditions offering the maximum efficiency of 91.85% and maximum adsorption capacity of 30.62 mg/g. Also considered were various competing anions together with nitrate ions in the solution. The results revealed that maximum nitrate adsorption could be obtained in the presence of phosphate anion via ion exchange mechanism. It could also offer the best fit for the adsorption isotherm and kinetic model for Langmuir and pseudo-second-order models. The investigation of thermodynamic parameters at 25 °C revealed that the ΔG°, ΔH°, and ΔS° were obtained −5.44, −46.56, and −0.14 kJ mol−1 K−1, respectively. [ABSTRACT FROM AUTHOR]

A study was carried out to determine the influence of the feather genotype, storage duration, temperature and method on the internal and external qualities of chicken table eggs. A total of 864 table eggs collected from naked neck (Nanaff), frizzle (nanaFf) and normal feathered (nanaff) birds were used in the study. A Completely Randomized Design of four factors namely, feather genotypes, storage temperatures (5ºC and 26ºC), storage duration (0, 7, 14, 21 and 28 days) and storage methods (with or without vegetable oil application) was used. The GLM procedure of GenStat (17th Edition) was used to determine the effects of the four factors and their interactions on external qualities (egg weight, length, and width, shell weight and thickness) and internal qualities (albumen height and weight, yolk height, weight, diameter and colour and Haugh unit) of table eggs. The effect of chicken genotype on proximate composition and nutritional values of table eggs were also determined. Feather genotype had significant (P<0.05) effect on yolk colour and weight whilst storage duration, temperature and method had significant (P<0.05) effects on all the internal qualities of eggs studied except effect of storage duration on yolk colour. The 2-way and 3-way interactions of the factors studied were important sources of variation for many of the internal qualities of eggs studied. With the exception of storage temperature, the other factors studied had significant (P<0.05) effects on many of the external qualities of eggs. The interactions of the factors were not significant (P>0.05) sources of variation for most of the external qualities of eggs. Mutant feather genes (Na and F) positively influence egg qualities which could be utilised to segment the commercial chicken egg market. [ABSTRACT FROM AUTHOR]

Bonelli's Eagle is an endangered species with little information on its ectoparasites. We studied their chewing lice (Phthiraptera: Amblycera, Ischnocera) infestations by visually searching the plumage of 64 wild and captive specimens. Three different species were identified: Degeeriella sp., Colpocephalum impressum and Laemobothrion maximum. This is the first case of Laemobothrion maximum on Bonelli's Eagle described. We also observe its haematophagous behavior. Due to the low prevalence of infestations, no alterations in the host health are described. [ABSTRACT FROM AUTHOR]

Many animals exhibit structural colors, which are often iridescent, meaning that the perceived colors change with illumination conditions and viewing perspectives. Biological iridescence is usually caused by multilayers or other periodic structures in animal tissues, which selectively reflect light of certain wavelengths and often result in a shiny appearance---which almost always comes with spatially varying highlights, thanks to randomness and irregularities in the structures. Previous models for biological iridescence tend to each target one specific structure, and most models only compute large-area averages, overlooking spatial variation in iridescent appearance. In this work, we build appearance models for biological iridescence using bird feathers as our case study, investigating different types of feathers with a variety of structural coloration mechanisms. We propose an approximate wave simulation method that takes advantage of quasi-regular structures while efficiently modeling the effects of natural structural irregularities. We further propose a method to distill our simulation results into distributions of BRDFs, generated using noise functions, that preserve relevant statistical properties of the simulated BRDFs. This allows us to model the spatially varying, glittery appearance commonly seen on feathers. Our BRDFs are practical and efficient, and we present renderings of multiple types of iridescent feathers with comparisons to photographic images. [ABSTRACT FROM AUTHOR]

Simple Summary: A feather-degrading bacterium, Bacillus velezensis PN1, was isolated, and solid-state fermentation conditions were optimized. The resulting fermented feather meal (FFM) was evaluated for bioavailability in broilers. B. velezensis PN1 showed the highest feather degradation rate, with optimal fermentation achieved at 37 °C for 48–72 h. FFM2, produced with 65% moisture at 37 °C for 48 h, was compared with FFM1 (produced at 27 °C) and commercial hydrolyzed feather meal (HFM). FFM2 was found to be more suitable for large-scale production due to its amino acid profile and fermentation efficiency. In a broiler growth trial, diets containing 5% FFM2 showed no significant difference in body weight, feed conversion ratio, or performance efficiency compared to the 5% HFM group (p > 0.05). However, both FFM2 and HFM groups showed lower weight gain than the 5% fish meal (FM) group (p < 0.05). Without supplemental amino acids, growth performance did not differ between FFM2 and HFM groups (p > 0.05). In conclusion, FFM produced by B. velezensis PN1 can completely replace HFM when included at 5% in broiler diets. In this study, an effective feather-degrading bacterium was isolated and the solid-state fermentation condition for feather degradation was optimized. The resulting fermented feather meal (FFM) was evaluated for its bioavailability in broilers. Four Bacillus strains were examined for feather degradation rates, with Bacillus velezensis PN1 exhibiting the highest rate (83.24%, p < 0.05). A 3 × 3 × 3 factorial design was used to test substrate moisture content (45%, 55%, 65%), temperature (27 °C, 37 °C, 47 °C), and incubation time (24, 48, 72 h) for optimized fermentation conditions. In vitro pepsin digestibility (IVPD) revealed a significant interaction between temperature and time (p < 0.05), and the optimal performance was achieved at 37 °C for 72 h, followed by 37 °C for 48 h. Considering production time and cost, FFM2 (produced with 65% moisture at 37 °C for 48 h) was further compared with FFM1 (produced under the same conditions but at a lower temperature of 27 °C), and commercial hydrolyzed feather meal (HFM). IVPD did not differ significantly between FFM1, FFM2, and HFM, as they all showed significantly higher digestibility compared to raw feathers (RFs). FFM1, as well as FFM2, had significantly higher histidine and lysine concentrations than RF (p < 0.05), while FFM2 had a significantly lower cysteine content (p < 0.05). Based on fermentation conditions and amino acid composition, FFM2 was considered more suitable for large-scale production and was used in a broiler growth trial. The inclusion of 5% FFM2 in the broiler diet did not significantly affect body weight at 35 days compared to the 5% HFM group (p > 0.05), although both groups showed significantly lower weight gain than the 5% fish meal (FM) group (p < 0.05). The feed conversion ratio and performance efficiency factor did not differ significantly between the FFM2, HFM, and FM groups (p > 0.05). In groups fed diets without supplemental crystalline amino acids, growth performance did not significantly differ between the HFM and FFM2 groups (p > 0.05), although both performed significantly worse than groups with amino acid supplementation. In conclusion, FFM produced by B. velezensis PN1 through solid-state fermentation enhances feather bioavailability in poultry and can completely replace HFM when included at 5% in broiler diets, offering a potential sustainable alternative for poultry nutrition on a commercial scale. [ABSTRACT FROM AUTHOR]

Feather is a sort of commonly used noninvasive material that can provide DNA and hormones for the research， monitoring and management of birds. However， feather vane is a fully keratinized tissue with very low content of DNA and hormones that often challenges the extraction. In the study， we developed a novel method to co-extract DNA and corticoste⁃ roid from feather vane， named DH-CoEx. The extraction efficiency and usability of DH-CoEx were evaluated by using feath⁃ ers from large feathers represented by the red crowned crane (Grus japonensis) and green peafowl (Pavo muticus) ， and small feathers represented by the chestnut bunting (Emberiza rutila) and little bunting (E. pusilla). The results showed that DH-CoEx could co-extracted total DNA and corticosteroid (cortisol) from feather vanes. The copy number of mitochondrial DNA (mtDNA) extracted from 5 mg feather reached 104 ， that could support amplification of 1，350 bp fragments. The nuclear DNA (nuDNA) could support genotyping of microsatellites with a success rate of 98. 11% - 99. 60% success rate for alleles less than 200 bp. The yield of cortisol co-extracted reach the level of normal single extraction approaches and supportive for physiological analysis. These results suggest that DH-CoEx is a simple and effective method to co-extract DNA and corticosteroids from a fully keratinized feather to support analysis of genetic markers and stress hormone in a broad range of application. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have contributed to the increase of heavy metals and to the alteration of their natural cycles in the environment. Mercury (Hg) is now considered to be one of the most toxic elements whose levels need to be monitored in abiogenic and biogenic environmental compartments. It can enter the body of animal in several ways, mainly through contaminated food. In this study, we compared mercury levels in mouse hair and songbird feathers from Zhongar Alatau National Park in Kazakhstan and from national parks in Slovakia. We sampled mice of the genus Apodemus and songbirds of three genera – Parus, Phylloscopus and Turdus. Total mercury concentrations were measured using DMA-80. The results showed higher levels of Hg bioaccumulation in Slovakia than in Kazakhstan in both songbirds and mice. The three songbird species from Kazakhstan showed differences due to different feeding niches. High levels were found in thrushes, which are considered insectivorous ground feeders, whereas the lowest mercury concentrations were detected in tits, which are considered more generalist feeders. In Slovakia, the trend was different, with tits having similar levels of Hg to thrushes, a reflection of the different levels of contamination of environmental components. Mice showed overall lower concentrations than birds at both sites.

This study explores the impact of feathers on the hydrodynamic drag experienced by diving birds, which is critical to their foraging efficiency and survival. Employing a novel experimental approach, we analyzed the kinematics of both feathered and nonfeathered projectiles during their transition from air to water using high‐speed imaging and an onboard accelerometer. The drag coefficients were determined through two methods: a direct calculation from the acceleration data and a theoretical approach fitted to the observed velocity profiles. Our results indicate that feathers significantly increase the drag force during water entry, with feathered projectiles exhibiting approximately double the drag coefficient of their smooth counterparts. These findings provide new insights into the role of avian feather morphology in diving mechanics and have potential implications for the design of bioinspired aquatic vehicles in engineering. The study also discusses the biological implications of increased drag due to feathers and suggests that factors such as body shape might play a more critical role in the diving capabilities of birds than previously understood. [ABSTRACT FROM AUTHOR]

Studies on the distribution characteristics and environmental relevance of per- and polyfluoroalkyl substances (PFAS) in waterbird feathers are scarce. In the present study, the concentrations of twenty-three PFAS in the remiges, coverts, body, down, and tail feathers of three common species of Ardeidae (little egret, grey heron, and Chinese pond-heron) in Poyang Lake were investigated. The total PFAS concentrations in the pinna and scapus were 38 – 42 ng/g dry weight (dw) and 21 – 38 ng/g dw, respectively; long-chain C9–14 perfluorocarboxylic acids were abundant in all feathers. Most PFAS accumulated in the pinna; however, perfluorohexane sulfonic acid and perfluorooctane sulfonamide were predominant in the scapus. The PFAS concentrations were higher in the tail and flight feathers than in the cover and body feathers. Furthermore, the concentrations of PFAS in waterbird feathers were comparable with those in fish and higher than those in benthic invertebrates, all of which originated from Poyang Lake. The PFAS profiles in feathers were significantly and positively correlated with those in fish (r > 0.71) and benthos (r > 0.43). These results suggest that waterbird feather is a suitable biomonitor of PFAS contamination in regional freshwater ecosystems.

[Objective] To explore the residual laws of typical antibacterial drugs in the feather and sebum of different broiler breeds, and evaluate the significance of feathers in monitoring the veterinary drug residues of broilers. [Method] Xueshan Chicken and AA broilers were fed with flufenicol or enrofloxacin for 21 days before slaughter, and drug residues in the feather and sebum at different time after withdrawal were determined. [Result]The residues of flufenicol and its metabolites (flufenicolamide) in the feathers of the two broiler breeds reached the highest level on the first day after drug withdrawal, and the contents were close. The total residue of enrofloxacin and its metabolites (ciprofloxacin) in the feathers of Xueshan Chicken reached its peak on the first day after withdrawal, and that in AA chicken reached its peak on the third day after withdrawal. The peak residual amount of drugs in the feather of Xueshan Chicken was greatly higher than that in AA broilers. Then the drug residual amount in the feather gradually decreased. On the 14th day after withdrawal, the residues of flufenicol and its metabolites in the the feathers of AA broilers and Xueshan Chicken were 281. 37 and 424. 30 μg/kg respectively, the content of enrofloxacin and its metabolites were 16. 03 and 26. 21 μg/kg, respectively. The residual laws of the two drug es in the sebum were similar to those in the feathers, suggesting that monitoring drug residues in the feathers could indirectly infer drug residues in edible tissues. [Conclusion]There were differences in the metabolism of the same drug in the feathers of different breeds of broilers, and the drug residues in the feathers could be used as the reference for monitoring the drug residues in broiler products. [ABSTRACT FROM AUTHOR]

In traditional Turkish archery, a feather is attached to the back of the arrows to prevent them from changing direction during flight after being shot. While these attached feathers ensure that the arrow flies on a smooth route after being shot, it causes aerodynamic factors that affect the movement of the arrow due to its friction with the air. In the study, the effects of the geometry parameters of the feathers in the traditional Turkish arrow on the aerodynamic factors were comparatively examined. To examine the movements of the arrows in the air, aerodynamic analyzes were carried out by using computational fluid dynamics CFD (Computational Fluid Dynamics) for each arrow type, taking into account the changes in the flow drag force values. By examining the acoustic power level in decibel units, the performance of the arrows from the bow was evaluated in terms of range and sound, and the results obtained through CFD (Computational Fluid Dynamics) were compared. [ABSTRACT FROM AUTHOR]

In the time of Internet of Things (IoT), alternating current electroluminescence (ACEL) has unique advantages in the fields of smart display and human–computer interaction. However, their reliance on external high-voltage AC power supplies poses challenges in terms of wearability and limits their practical application. This paper proposed an innovative scheme for preparing a feather triboelectric nanogenerator (F-TENG) using recyclable and environmentally friendly material. The highest open-circuit voltage, short-circuit current, and transferred charge of SF6-treated F-TENGs can reach 449 V, 63 µA, and 152 nC, which enables easy lighting of BaTiO3-doped ACEL devices. Using a human electrical potential, a single-electrode F-TENG is combined with ACEL device for self-powered fingerprint recognition display. These works achieve self-powered flexible wearable ACEL devices, which are not only efficient and portable but also have good application prospects in the human–computer interaction, functional displays, and wearable electronic devices. [ABSTRACT FROM AUTHOR]

Non-invasive proxies, such as fur and feathers, are likely to be increasingly used to assess the potential exposure of chemicals, including trace metals and metalloids. However, the amount of external contamination is usually unknown, and there is no standard method for removing external contamination of trace metals in fur or feathers. To date, 40 % of studies published related to the measurement of trace metal levels in fur or the hair of non-human mammals and 24 % of studies in feathers do not state any washing methods or did not wash the samples before analysis. We assessed three washing techniques to remove external contamination of arsenic (As), lead (Pb), and zinc (Zn) from bat fur. We selected the three most frequently used fur washing methods from literature. To test these methods, fur samples from great flying foxes (Pteropus neohibernicus neohibernicus, n=15 individuals) from Papua New Guinea preserved over eight decades (AMNH, USA) were used. Percentages of trace metal removed are 87.19 % (SD= 12.28), 92.99 % (SD= 5.5) and 88.57 % (SD= 9.33) for As, 54.72 % (SD= 31.64), 55.89 % (SD= 37.87), and 53.93 % (SD= 41.28) for Pb, and 74.03 % (SD= 22.96), 22.93 % (SD= 73), and 24.95 % (SD= 49.5) for Zn using M2, M3, and M4, respectively. We also assessed four washing techniques to remove external contamination of arsenic (As), mercury (Hg), and zinc (Zn) from bird feathers. We identified the four most prevalent washing techniques in the literature used for feathers. We used feathers from the great horned owl (Bubo virginianus) and the great blue heron (Ardea herodias) to test these methods. Percentages of trace metal removed are 34.35 % (SD= 44.22), 69.22 % (SD= 36.5), 62.59 % (SD= 48.37), and 80.89 % (SD= 14.54) for As, 66.97 % (SD= 13.26), 29.4 % (SD= 67.06), 49.68 % (SD= 42.33), and 28.88 % (SD= 69) for Hg, and

Bird plumage coloration is a complex and multifactorial process that involves both genetic and environmental factors. Diverse pigment groups contribute to plumage variation in different birds. In parrots, the predominant green color results from the combination of 2 different primary colors: yellow and blue. Psittacofulvin, a pigment uniquely found in parrots, is responsible for the yellow coloration, while blue is suggested to be the result of light scattering by feather nanostructures and melanin granules. So far, genetic control of melanin-mediated blue coloration has been elusive. In this study, we demonstrated that feather from the yellow mutant rose-ringed parakeet displays loss of melanosome granules in spongy layer of feather barb. Using whole genome sequencing, we found that mutation in SLC45A2, an important solute carrier protein in melanin synthetic pathway, is responsible for the sex-linked yellow phenotype in rose-ringed parakeet. Intriguingly, one of the mutations, P53L found in yellow Psittacula krameri is already reported as P58A/S in the human albinism database, known to be associated with human OCA4. We further showed that mutations in SLC45A2 gene affect melanin production also in other members of Psittaculidae family such as alexandrine and plum-headed parakeets. Additionally, we demonstrate that the mutations associated with the sex-linked yellow phenotype, localized within the transmembrane domains of the SLC45A2 protein, affect the protein localization pattern. This is the first evidence of plumage color variation involving SLC45A2 in parrots and confirmation of associated mutations in the transmembrane domains of the protein that affects its localization. [ABSTRACT FROM AUTHOR]

Geographic distribution models of environmentally stable isotopes (the so‐called "isoscapes") are widely employed in animal ecology, and wildlife forensics and conservation. However, the application of isoscapes is limited to elements and regions for which the spatial patterns have been estimated. Here, we focused on the ubiquitous yet less commonly used stable sulfur isotopes (δ34S). To predict the European δ34S isoscape, we used 242 feather samples from Eurasian Reed Warbler (Acrocephalus scirpaceus) formed at 69 European wetland sites. We quantified the relationships between sample δ34S and environmental covariates using a random forest regression model and applied the model to predict the geographic distribution of δ34S. We also quantified within‐site variation in δ34S and complementarity with other isotopes on both individual and isoscape levels. The predicted feather δ34S isoscape shows only slight differences between the central and southern parts of Europe while the coastal regions were most enriched in 34S. The most important covariates of δ34S were distance to coastline, surface elevation, and atmospheric concentrations of SO2 gases. The absence of a systematic spatial pattern impedes the application of the δ34S isoscape, but high complementarity with other isoscapes advocates the combination of multiple isoscapes to increase the precision of animal tracing. Feather δ34S compositions showed considerable within‐site variation with highest values in inland parts of Europe, likely attributed to wetland anaerobic conditions and redox sensitivity of sulfur. The complex European geography and topography as well as using δ34S samples from wetlands may contribute to the absence of a systematic spatial gradient of δ34S values in Europe. We thus encourage future studies to focus on the geographic distribution of δ34S using tissues from diverse taxa collected in various habitats over large land masses in the world (i.e., Africa, South America, or East Asia). [ABSTRACT FROM AUTHOR]

Feathers cause environmental problems worldwide when poultry processing industries produce it as a waste of billions of tons yearly. This waste is not easily decomposed by natural agents in a short time. Currently, Streptomyces spp. are known as a highly enzymatic activity species which can efficiently degrade feathers to products. Therefore, the aim of this study was to screen for Streptomyces strains with high feather-degrading activity. A total of 46 strains of Streptomyces spp. were isolated from different soils of Danang city and other vicinities, in which 13 isolates showed the ability to degrade casein and gelatin. The protease activity of H3, N5, and N7 isolates were higher than others. In particular, N7 strain had the highest protease activity with 70.33 U/mL and degraded 97.79% feather after 5 days of cultivation. Based on the sequence analysis of 16S rRNA, N7 was identified as homologous to Streptomyces anandii.

As a nondestructive means of environmental monitoring, bird feathers have been used to analyze levels of per- and polyfluoroalkyl substances (PFASs) in specific environments. In this study, feather samples from 10 waterbird species around Poyang Lake were collected, and a pretreatment method for PFASs in feathers was optimized. The results showed that a combined cleaning method using ultrapure water and n-hexane effectively removed external PFASs. Twenty-three legacy and emerging PFASs were identified in the feathers of waterbirds, of which hexafluoropropylene oxides (HFPOs), chlorinated polyfluoroalkyl ether sulfonates (Cl-PFESAs), and sodium p-perfluorinated noneoxybenzene sulfonate (OBS) were reported for the first time, with their concentrations ranging from 0.060–2.4 ng·g−1 dw, 0.046–30 ng·g−1 dw, and lower than the method detection limit to 30 ng·g−1 dw, respectively. Compound- and species-specific bioaccumulation of PFASs was observed in the feathers of different waterbird species, suggesting that different PFAS types can be monitored through the selection of different species. Moreover, the concentrations of most PFCAs (except perfluorobutyric acid), perfluorooctane sulfonate (PFOS), and perfluorooctane sulfonamide (FOSA) were significantly positively correlated with δ15N (p < 0.05), while the concentrations of HFPOs, Cl-PFESAs, and OBS had significant positive correlations with δ13C. This indicates that the bioaccumulation of legacy and emerging PFASs in waterbird feathers is affected by their trophic level, feeding habits, and foraging area.

Abstract Geographic distribution models of environmentally stable isotopes (the so‐called “isoscapes”) are widely employed in animal ecology, and wildlife forensics and conservation. However, the application of isoscapes is limited to elements and regions for which the spatial patterns have been estimated. Here, we focused on the ubiquitous yet less commonly used stable sulfur isotopes (δ34S). To predict the European δ34S isoscape, we used 242 feather samples from Eurasian Reed Warbler (Acrocephalus scirpaceus) formed at 69 European wetland sites. We quantified the relationships between sample δ34S and environmental covariates using a random forest regression model and applied the model to predict the geographic distribution of δ34S. We also quantified within‐site variation in δ34S and complementarity with other isotopes on both individual and isoscape levels. The predicted feather δ34S isoscape shows only slight differences between the central and southern parts of Europe while the coastal regions were most enriched in 34S. The most important covariates of δ34S were distance to coastline, surface elevation, and atmospheric concentrations of SO2 gases. The absence of a systematic spatial pattern impedes the application of the δ34S isoscape, but high complementarity with other isoscapes advocates the combination of multiple isoscapes to increase the precision of animal tracing. Feather δ34S compositions showed considerable within‐site variation with highest values in inland parts of Europe, likely attributed to wetland anaerobic conditions and redox sensitivity of sulfur. The complex European geography and topography as well as using δ34S samples from wetlands may contribute to the absence of a systematic spatial gradient of δ34S values in Europe. We thus encourage future studies to focus on the geographic distribution of δ34S using tissues from diverse taxa collected in various habitats over large land masses in the world (i.e., Africa, South America, or East Asia).

Concentrations of 4 potentially toxic elements (As, Cd, Hg, Pb) were investigated in the feather, liver, kidney, and bone of great cormorants (Phalacrocorax carbo). The tissue samples were taken at the Central Tisza - Jászság Nature Conservation Area in Hungary. They were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The goal of the investigation was to analyse the metal burden of the above-mentioned elements in the various tissues of these wild birds and to provide important information for monitoring the environmental pollution. Amongst the examined potentially toxic elements no statistical gender difference was observed, so the data were not separated based on them during the statistical analysis. The concentration of mercury was the highest in the feather, followed by the liver, kidney, and bone. The lead was detected in the feather with the highest level followed by the kidney, liver, and bone. The cadmium was determined in all investigated tissues with the next descending order: kidney > bone > liver > feather. Highest arsenic concentration was measured in the feather, followed by liver, kidney, and bone with the same concentration. The detected concentrations of the investigated potentially toxic elements in different tissues of great cormorants (feathers, liver, kidney, bone) means that the living area of this birds is not highly contaminated to induce health problems or toxic signs, or even other undesirable effect in the animals. [ABSTRACT FROM AUTHOR]

The present study evaluated the potential utility of feather samples for the convenient and accurate detection of avian influenza virus (AIV) in commercial poultry. Feather samples were obtained from AIV-negative commercial layer facilities in Iowa, USA. The feathers were spiked with various concentrations (106 to 100) of a low pathogenic strain of H5N2 AIV using a nebulizing device and were evaluated for the detection of viral RNA using a real-time RT-PCR assay immediately or after incubation at −20, 4, 22, or 37 °C for 24, 48, or 72 h. Likewise, cell culture medium samples with and without the virus were prepared and used for comparison. In the spiked feathers, the PCR reliably (i.e., 100% probability of detection) detected AIV RNA in eluates from samples sprayed with 103 EID50/mL or more of the virus. Based on half-life estimates, the feathers performed better than the corresponding media samples (p < 0.05), particularly when the samples were stored at 22 or 37 °C. In conclusion, feather samples can be routinely collected from a poultry barn as a non-invasive alternative to blood or oropharyngeal–cloacal swab samples for monitoring AIV. [ABSTRACT FROM AUTHOR]

Many biological materials may be considered as cellular materials, for example, soft tissues, but also bones, wood, or foam‐like medulla in a bird feather. The cells may be filled with a fluid or just with air, have different size, shape, and wall thickness. Less is known about how the mechanical and morphological parameters of the cellular materials influence their biologically relevant functions. A simple descriptive 2D numerical model of a cellular material based on Voronoi diagrams is presented here which aims prompt investigation how structural parameters influence its physical properties. The preliminary numerical simulations demonstrate that with an increasing wall thickness the energy dissipation increases and with an increasing cell density also an average stress increases. Other interesting results are that an increased dissipation constant of cellular material reduces the stress, and that in hierarchical foams the dissipation takes place mostly in the thick walls. The presented approach allows screening the influence of further material features and structural parameters, such as for example, different kinds of gradients or different properties of biological or biologically inspired cellular materials at different loading conditions. Direct comparison of different real biological structures could be also performed, especially when real experimental measurements are impossible. [ABSTRACT FROM AUTHOR]

Feathers are most important parts of avian and commonly found at scene of crime. The identification of species from feather samples could help in crime investigation particularly wildlife trafficking cases. Analysis of such evidence can provide a link between the criminal and the crime scene and thereby be utilized as associative evidence in the court of law. In the present study, twelve feather samples of Galliformes bird has been analysed using ATR-FTIR spectroscopy. Chemometric methods such as Principal Component Analysis (PCA) and Linear Discrimination Analysis (LDA) were performed on the obtained spectra for objective interpretation of results. PC1, PC2, PC3, and PC4 were able to explain a variance of 93 %, 4 %, 2 %, and 1 % respectively. The score plots showed separate clusters for all twelve bird species. The LDA model classified all the twelve species into their respective categories with a 100 % accuracy. Overall, the presented methodology has shown a potential for application in forensic casework

Immature feathers are known replication sites for high pathogenicity avian influenza viruses (HPAIVs) in poultry. However, it is unclear whether feathers play an active role in viral transmission. This study aims to investigate the contribution of the feather epithelium to the dissemination of clade 2.3.4.4b goose/Guangdong/1996 lineage H5 HPAIVs in the environment, based on natural and experimental infections of domestic mule and Muscovy ducks. During the 2016–2022 outbreaks, H5 HPAIVs exhibited persistent and marked feather epitheliotropism in naturally infected commercial ducks. Infection of the feather epithelium resulted in epithelial necrosis and disruption, as well as the production and environmental shedding of infectious virions. Viral and feather antigens colocalized in dust samples obtained from poultry barns housing naturally infected birds. In summary, the feather epithelium contributes to viral replication, and it is a likely source of environmental infectious material. This underestimated excretion route could greatly impact the ecology of HPAIVs, facilitating airborne and preening-related infections within a flock, and promoting prolonged viral infectivity and long-distance viral transmission between poultry farms.

The concentrations of mercury (Hg) and lead (Pb) in feather samples of nine bird's species (n = 65) were determined from southeastern areas of Iran, Hamun International Wetlands. Hg concentrations were ranged from 0.40 to 3.00 mg/kg dry wt and from 0.38 to 1.76 mg/kg for primary and secondary feathers, respectively. Furthermore, Pb concentrations were ranged from 1.43 to 4.10 mg/kg and from 1.28 to 3.65 mg/kg for primary and secondary feathers, respectively. Deposition of metals varied significantly among the primary and secondary feathers of systematic category (families) for Hg and Pb (p < 0.001). It was found that there is a significant difference in feather Hg and Pb concentrations across species (p < 0.001) with highest concentrations in saker falcon (Falconidae) (Hg = 3.00 mg/kg and Pb = 4.10 mg/kg, primary feather) followed by little owl (Strigidae). Grey francolin (Phasianidae) contained the least amount of Hg (0.40 mg/kg) and Pb (1.43 mg/kg) in primary feather. The results showed that the highest concentrations of heavy metals were related to carnivores. Fish predators, omnivores, and insectivores were examined at the next level of metal concentration, with herbivores having the lowest concentrations of lead (1.43 mg/kg) and mercury (0.40 mg/kg). Birds with an open grasslands feeding strategy had the highest mercury and lead concentration. The average value for Pb was on the border of harmful effects (4 mg/kg). The results of this study indicate that mercury levels are lower than the threshold level for reproductive and behavioral harm (5 mg/kg). [ABSTRACT FROM AUTHOR]

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One of the biggest problems in the healing process of acute and chronic wounds is the emergence of secondary symptoms, such as infections causing delayed healing. The most effective way to solve this problem is to speed up the healing process. Natural-based products play an active role in accelerating this process even more. The current work is focused on developing an alternative natural wound dressing by creating a mucilage film from quince seed with keratin obtained from feathers. The study includes the following chemical characterizations: FTIR (Fourier transform infrared spectroscopy), TGA (thermogravimetric analysis), and SEM (scanning electron microscopy). In addition, thickness and antioxidant activity tests were performed to obtain more information about the films. The thickness of the composite films increased with the increase of keratin amount. The antioxidant activities of the films varied between 17.60 and 27.48%. Besides, the effect of keratin amount on the changing hydrophobicity of the films was investigated by contact angle measurement, and it was determined that increasing keratin amount increased the hydrophobicity of the films. The results of the analysis have shown that goose feather keratin is a potential alternative source for obtaining both economic and environmentally friendly products in areas like wound healing. [ABSTRACT FROM AUTHOR]

The knowledge of migratory connectivity is important for understanding the potential drivers of populations and it is thus important for conservation implications. Migratory connectivity of species can be studied using exogenous, such as rings and transmitters, or endogenous markers, such as stable isotopes and trace elements. The use of trace elements has been much less frequently studied compared to stable isotopes. Trace elements can be studied from the feathers of birds and this does not necessarily require trapping of individuals. Here we studied the variation of 18 different trace elements in feathers of two long‐distance trans‐African migrants, willow warblers Phylloscopus trochilus and barn swallows Hirundo rustica, using body feathers of museum specimens of birds from Finnish breeding grounds. The trace elements were measured using laser‐ablation inductively‐coupled‐plasma mass‐spectrometry (LA‐ICP‐MS). We show that trace element concentrations were relatively stable along the rachis within the same feather except in Ni and S, which showed a quadratic pattern. In general, variation within feathers of the same individuals was smaller than in feathers between individuals for most elements. Furthermore, concentrations of 11 trace elements showed significantly higher concentrations in willow warbler feathers collected in spring than in autumn, moulted in African wintering grounds and European breeding grounds, respectively. Last, concentrations of seven trace elements were significantly higher in the spring feathers of willow warblers compared to barn swallows. This suggests that trace elements could be used to separate moulting grounds of the birds on the larger scale within the same species, but also sampling design should be carefully considered. [ABSTRACT FROM AUTHOR]

In the integration of the circular economy, keratin hydrolysis is essential for preventing keratin accumulation in the environment and offers opportunities for utilising the resultant protein hydrolysate. Keratin hydrolysate can serve as an alternative nitrogen source for microbial cultures, and thus promote cost-effective production of commercially valuable metabolites such as biofuels, vitamins, organic acids, pigments, and polysaccharides. Considering the amount of keratin waste generated annually, particularly chicken feathers, exploring alternative approaches for utilising keratin hydrolysate could stimulate further research. [ABSTRACT FROM AUTHOR]

Background: A major portion of poultry feather waste is constituted by keratin, which is recalcitrant to degradation by common proteases. Feather waste contributes to a significant volume of biowaste load to the environment. Valorization of these wastes into various products has been attempted by many researchers. The present study aimed to produce peptides (molecular weight

The increase in the generation of chicken feathers, due to the large production of the poultry industry, has created the need to search for ecologically safer ways to manage these residues. As a sustainable alternative for recycling keratin waste, we investigated the ability of the bacterium Ochrobactrum intermedium to hydrolyze chicken feathers and the valorization of the resulting enzymes and protein hydrolysate. In submerged fermentation with three different inoculum sizes (2.5, 5.0, and 10.0 mg of bacterial cells per 50 mL of medium), the fastest degradation of feathers was achieved with 5.0 mg cells, in which a complete decomposition of the substrate (96 h) and earlier peaks of keratinolytic and caseinolytic activities were detected. In the resulting protein hydrolysate, we noticed antioxidant and Fe2+ and Cu2+ chelating activities. ABTS scavenging, Fe3+-reducing ability and metal chelating activities of the fermentative samples followed the same trend of feather degradation; as feather mass decreased in the media, these activities increased. Furthermore, we noticed about 47% and 60% dispersion of established 7-day biofilms formed by S. aureus after enzymatic treatment for 5 h and 24 h, respectively. These findings highlight the potential use of this bacterium as an environmentally friendly alternative to treat this poultry waste and offer valuable products. [ABSTRACT FROM AUTHOR]

Valorization of chicken feather is a long‐sought approach for its sustainable disposal. Being protein rich, hydrolyzed chicken feather has a wide range of applications, not limited to formulation of microbiological culture media, animal feed, and biofertilizers, but extends to synthesis of bioplastic films, cosmetics, and biomedicals. In this study, a potent keratinolytic isolate was recovered from soil and identified by 16S rRNA as Bacillus thuringiensis. Feather degradation by the isolate was optimized through response surface methodology. First, one‐variable‐at‐a‐time technique to assign the factors that affect feather degradation, then Box–Behnken central composite design model were employed. The model, involving three independent variables (initial pH, inoculum size, and concentration of supplementary glucose), was significant (R2 = 0.9716). According to the model, complete feather degradation is obtained at an inoculum size of B. thuringiensis B4 equal to 1 × 1010 CFU/ml, when feather meal broth is supplemented with 1.5% (w/v) glucose and pH adjusted to 8.5. Protein content of the lysate was 327.8 ± 25 μg/ml, and no carbohydrates were detected. SEM/EDX analysis has shown that the hydrolysate consisted mainly of O, P, S, and Se in addition to carbon, while FTIR images assured the presence of carboxyl and amino groups characteristic of peptides and amino acids. [ABSTRACT FROM AUTHOR]

A distinctive isolate was discovered and visually recognized as a member of the genus Didymella during a routine examination of Coelomycetes isolated from diverse fruit juices. Based on sequencing of the internal transcribed spacer (ITS), the fungus was identified as Didymella keratinophila since it showed a 100% identity to the type strain. The strain thrived and produced keratinase and collagenase enzymes by hydrolyzing native chicken feathers in submerged fermentation (SmF). After 10 days of fermentation at 30 °C, pH 9 using sodium nitrate as a nitrogen supply produced the highest keratinase activity of 8780 ± 620 U/mL/min, while pH 6 and beef extract produced the maximum collagenase activity of 11,230 ± 1290 U/mL/min. The partially-purified keratinase enzyme worked best at pH 7.0 and 45 °C, exhibiting a specific activity of 44,903 ± 1555 U/mg protein. The activity of the partially-purified collagenase enzyme was excellent at pH 6.0 at 35 °C, generating 15,753 ± 110 U/mg enzyme-specific activity. Mn2+ and K+ were the most efficient inhibitors of keratinases and collagenase, respectively. Both EDTA and metal ions significantly decreased the activity of keratinase and collagenase. This report identified a workable supplier of collagenase and keratinase enzymes derived from chicken feathers, offering a reliable way to exploit and manage these wastes for obtaining high-value products. [ABSTRACT FROM AUTHOR]

Mercury (Hg) and stable carbon and nitrogen isotope ratios were analysed in body feathers from nestlings of white-tailed eagles (Haliaeetus albicilla) (WTE; n = 13) and Northern goshawks (Accipiter gentilis) (NG; n = 8) and in red blood cells (RBC) from NG (n = 11) from Norway. According to linear mixed model, species factor was significant in explaining the Hg concentration in feathers (LMM; p < 0.001, estimate (WTE) = 2.51, 95% CI = 1.26, 3.76), with concentrations higher in WTE (3.01 ± 1.34 µg g−1 dry weight) than in NG (0.51 ± 0.34 µg g−1 dry weight). This difference and the isotopic patterns for each species, likely reflect their diet, as WTE predominantly feed on a marine and higher trophic-chain diet compared to the terrestrial NG. In addition, Hg concentrations in RBCs of NG nestlings were positively correlated with feather Hg concentrations (Rho = 0.77, p = 0.03), supporting the potential usefulness of nestling body feathers to biomonitor and estimate Hg exposure. Hg levels in both species were generally below the commonly applied toxicity threshold of 5 µg g−1 in feathers, although exceeded in two WTE (6.08 and 5.19 µg g−1 dry weight). [ABSTRACT FROM AUTHOR]

All living jawed vertebrates possess teeth or did so ancestrally. Integumental surface also includes the cornea. Conversely, no other anatomical feature differentiates the clades so readily as skin appendages do, multicellular glands in amphibians, hair follicle/gland complexes in mammals, feathers in birds, and the different types of scales. Tooth-like scales are characteristic of chondrichthyans, while mineralized dermal scales are characteristic of bony fishes. Corneous epidermal scales might have appeared twice, in squamates, and on feet in avian lineages, but posteriorly to feathers. In contrast to the other skin appendages, the origin of multicellular glands of amphibians has never been addressed. In the seventies, pioneering dermal–epidermal recombination between chick, mouse and lizard embryos showed that: (1) the clade type of the appendage is determined by the epidermis; (2) their morphogenesis requires two groups of dermal messages, first for primordia formation, second for appendage final architecture; (3) the early messages were conserved during amniotes evolution. Molecular biology studies that have identified the involved pathways, extending those data to teeth and dermal scales, suggest that the different vertebrate skin appendages evolved in parallel from a shared placode/dermal cells unit, present in a common toothed ancestor, c.a. 420 mya. [ABSTRACT FROM AUTHOR]

Stable isotope analysis of feathers is widely used in bird ecology. Generally, studied birds should be captured to collect feather samples in a way that clarifies the attribution of feather samples. As some endangered birds cannot be captured, feather sampling is the only feasible method for isotopic research. However, whether it can be used for research on individuals remains to be clarified. In this study, the values of d13C and d15N of the rachises and barbules of 27 feathers from 3 pigeons were measured, and cluster analysis of these samples was carried out by using the system clustering method. The results showed a significant difference between the isotope values of the rachis and barbules from the same feather. In addition, the isotope values of the rachises and barbules differed between individuals, although the food sources of the samples might be slightly different. Based on the above results, the cluster analysis was able to distinguish individuals, with the highest accuracy of 85%; the more factors that were used, the higher the accuracy of the clustering. [ABSTRACT FROM AUTHOR]