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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]