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Chicken feather valorization by thermal alkaline pretreatment followed by enzymatic hydrolysis for protein-rich hydrolysate production

Cheong CW, Lee YS, Ahmad SA, Ooi PT, Phang LY

Waste Manag, 2018 Sep;79:658-666.
PMID: 30343798 DOI: 10.1016/j.wasman.2018.08.029

A huge amount of feathers is generated as a waste every year. Feathers can be a protein source if it is treated with an appropriate method. The present study investigates feasibility of autoclave alkaline and microwave alkaline pretreatments to be combined with enzymatic treatment for feather solubilization and protein production. Hydrolysis of chicken feather by autoclave alkaline pretreatment followed by an enzymatic method (AAS) or microwave alkaline pretreatment followed by an enzymatic method (MAS) was optimized by response surface methodology. Various NaOH concentrations for autoclave alkaline pretreatment (0.01-0.1 M) and microwave-alkaline pretreatment (0.01-0.05 M) were applied. The holding time for both pretreatments ranged from 1 to 10 min. The pretreated feathers were subjected to enzymatic hydrolysis using a commercial enzyme prior to analysis of protein content, feather solubilization, functional groups, and elemental composition (carbon, hydrogen, nitrogen and sulfur) of the treated feathers. The results revealed that both autoclave alkaline pretreatment and microwave alkaline pretreatment under optimized conditions of 0.068 M NaOH, 2 min holding time, 105 °C and 450 W, 0.05 M NaOH for 10 min, respectively, enhanced the subsequent Savinase hydrolysis of chicken feathers to achieve more than 80% degradation and more than 70% protein recovery. Fourier transform infrared spectroscopy results showed that both thermal-alkaline pretreatments weakened the structure of the feather. Reduction of carbon, nitrogen, and sulfur occurred in both thermal-alkaline pretreatments of feathers indicating degradation of the feather as well as protein release. Thermal-alkaline pretreatment may be a promising method for enhancing the enzymatic hydrolysis of chicken feathers and for producing a protein-rich hydrolysate.

Matched MeSH terms: Feathers*
[Relative lengths of juvenile primaries in European and Indo-Malaysian woodpeckers (Picidae)]

Sutter E

Rev. Suisse Zool., 1974 Oct;81(3):684-9.
PMID: 4445815
Matched MeSH terms: Feathers/growth & development*
Influence of chicken feather waste derived protein hydrolysate on the growth of tea plants under different application methods and fertilizer rates

Raguraj S, Kasim S, Jaafar NM, Nazli MH

Environ Sci Pollut Res Int, 2023 Mar;30(13):37017-37028.
PMID: 36564696 DOI: 10.1007/s11356-022-24758-z

Modern agriculture prioritizes eco-friendly and sustainable strategies to enhance crop growth and productivity. The utilization of protein hydrolysate extracted from chicken feather waste as a plant biostimulant paves the path to waste recycling. A greenhouse experiment was performed to evaluate the implications of different doses (0, 1, 2, and 3 g L-1) of chicken feather protein hydrolysate (CFPH), application method (soil and foliar), and fertilizer rate (50% and 100%) on the growth performance of tea nursery plants. The highest dose of CFPH (3 g L-1) increased the shoot and root dry weights by 43% and 70%, respectively over control. However, no significant differences were observed between 2 and 3 g L-1 doses in plant dry weight, biometric, and root morphological parameters. Foliar application of CFPH significantly increased all the growth parameters compared to soil drenching except N, P, and K concentrations in leaves and roots. Plants grown under 100% fertilizer rate showed better growth performance than 50% fertilizer rate. Tea nursery plants treated with foliar 2 g L-1 dose and grown under full fertilizer rate recorded the highest plant dry weight, root length, and root surface area. However, tea plants under 50% fertilizer rate and treated with foliar 2 and 3 g L-1 doses sustained the growth similar to untreated plants under 100% fertilizer rate. The significantly higher N, P, and K concentrations in leaves were observed in plants treated with soil drenching of 2 and 3 g L-1 CFPH doses under 100% fertilizer rate. Our results indicate that the application of CFPH as a foliar spray is highly effective in producing vigorous tea nursery plants suitable for field planting, eventually capable of withstanding stress and higher yield.

Matched MeSH terms: Feathers/chemistry
Fulltext Penetrating ocular trauma by nail of a badminton feather shuttle cock: A rare case report

Das S, Singh V, Saurabh K

Indian J Ophthalmol, 2020 06;68(6):1209-1211.
PMID: 32461485 DOI: 10.4103/ijo.IJO_1681_19

Sports-related ocular traumas may be rare, but can have devastating and disabling consequences. The causes of eye-related injuries depend on the type of sports popular in a particular area or country. Badminton is a popular sport played by all age groups and socioeconomic segments and is popular in many parts of the world. It is most popular in South-East Asia, accounting for two-thirds of all ocular sports injury in Malaysia. In India, badminton has become quite popular in recent years. Shuttlecocks in badminton have been shown to be responsible for a high number of outpatient ocular sports-related, mostly blunt injuries. We report an unusual case of penetrating ocular injury due to a feather shuttlecock and its surgical management.

Matched MeSH terms: Feathers
Biomonitoring of heavy metals in the feathers of House crow (Corvus splendens) from some metropolitans of Asia and Africa

Iqbal F, Wilson R, Ayub Q, Song BK, Krzeminska-Ahmedzai U, Talei A, et al.

Environ Sci Pollut Res Int, 2023 Mar;30(13):35715-35726.
PMID: 36536201 DOI: 10.1007/s11356-022-24712-z

Urban-dwelling birds can be useful biomonitors to assess the impact of the urbanisation on both public and wildlife health. Widely distributed urban bird species, the House crow, was studied for heavy metal accumulation levels from nine cities of South Asia, Southeast Asia and Africa that border the Indian Ocean. Feathers were spectroscopically investigated for the deposition of ten heavy metals, i.e. As, Zn, Pb, Cd, Ni, iron Fe, Mn, Cr, Cu and Li. Fe and Zn were found to be the most prevalent metals in all sites. Measured concentrations of Pb (4.38-14.77 mg kg-1) overall, and Fe (935.66 mg kg-1) and Cu (67.17 mg kg-1) at some studied sites were above the toxicity levels reported lethal in avian toxicological studies. Multivariate analysis and linear models supported geographical location as a significant predictor for the level of most of the metals. Zn and Cu, generally and Pb, Cd, Mn, Cr at some sites exhibited potential bioaccumulation from surrounding environments. Inter-species comparisons strengthen the inference that the House crow is a reliable bioindicator species for the qualitative assessment of local urban environmental pollution and could be a useful tool for inter-regional monitoring programs.

Matched MeSH terms: Feathers/chemistry
Mitochondrial genomes of the jungle crow Corvus macrorhynchos (Passeriformes: Corvidae) from shed feathers and a phylogenetic analysis of genus Corvus using mitochondrial protein-coding genes

Krzeminska U, Wilson R, Rahman S, Song BK, Seneviratne S, Gan HM, et al.

Mitochondrial DNA A DNA Mapp Seq Anal, 2016 Jul;27(4):2668-70.
PMID: 26075478 DOI: 10.3109/19401736.2015.1043540

The complete mitochondrial genomes of two jungle crows (Corvus macrorhynchos) were sequenced. DNA was extracted from tissue samples obtained from shed feathers collected in the field in Sri Lanka and sequenced using the Illumina MiSeq Personal Sequencer. Jungle crow mitogenomes have a structural organization typical of the genus Corvus and are 16,927 bp and 17,066 bp in length, both comprising 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal subunit genes, and a non-coding control region. In addition, we complement already available house crow (Corvus spelendens) mitogenome resources by sequencing an individual from Singapore. A phylogenetic tree constructed from Corvidae family mitogenome sequences available on GenBank is presented. We confirm the monophyly of the genus Corvus and propose to use complete mitogenome resources for further intra- and interspecies genetic studies.

Matched MeSH terms: Feathers/metabolism; Feathers/physiology
Fulltext Treatments of chicken feather waste

Cheong, Chooi Wei, Siti Aqlima Ahmad, Ooi, Peck Toung, Phang, Lai Yee

The Pertanika Journal of Scholarly Research Reviews, 2017;3(1):32-41.
MyJurnal

Feather waste is a potential renewable source to recover valuable products because it is being a rich source of keratin proteins and amino acids. It can be used to make feather meal, fertilizer and yarn sizing agent. Various treatments have been used to recover the protein from chicken feathers as the keratinous feathers cannot be easily degraded due to its tough structure. This paper reviews the existing treatment methods used to hydrolyze chicken feathers. The treatment methods for feather hydrolysis such as physical, chemical, biological and combined treatments as well as their advantages and challenges are highlighted. The effects of these treatments on feather hydrolysis are complex and vary in regards to the performance of feather hydrolysis and product yielded. Hence, it is important to choose an appropriate treatment method since the type of treatment applied affects the product yielded qualitatively and quantitatively. In addition, the economic assessment and environmental impact of the choice of treatment should be considered also.

Matched MeSH terms: Feathers
Fulltext Properties of chicken head gelatins as affected by extraction method

Ee, S.C., Saari, N., Abas, F., Ismail, A., Abu Bakar, M.K., Bakar, J.

International Food Research Journal, 2019;26(2):499-508.
MyJurnal

Malaysia is a surplus poultry producing country with well-established commercial slaughtering and processing plants. Immense quantity of heads, feet, viscera, blood and feathers are usually discarded and not optimally utilized. Chicken heads are rich in protein, and could be a potential source of gelatin. The aim of the present work was therefore to find a simpler, faster, cheaper and greener gelatin extraction technology as compared to current available methods of gelatin extraction from poultry heads. A comparison of three different gelatin extraction methods with alkaline-acid pretreatment (E1), single acid pretreatment (E2) and single alkaline pretreatment (E3) were studied to extract gelatin from chicken heads. E1 and E2 produced gelatins of Type A, while E3 produced gelatin of Type B. High bloom gelatin (>300 g) with

Matched MeSH terms: Feathers
Biodiesel synthesis from chicken feather meal using S/AlMCM-41 catalyst and engine performance analysis

Almalki ASA, Alhadhrami A, Alsanie WF, Kamarudin SK, Pugazhendhi A

Environ Res, 2024 Apr 01;246:118060.
PMID: 38157966 DOI: 10.1016/j.envres.2023.118060

In this study, Sulphated/AlMCM-41 (S/AlMCM-41) catalysts were synthesized and used to produce biodiesel from CFMO. Different percentages of S/AlMCM-41 catalysts were prepared and characterized by X-ray diffraction, BET studies, TPD, and SEM-EDS analysis. Sulphur incorporation to the MCM framework though reduced the surface area, and pore volume of the catalyst, sufficient acidity were produced in the catalyst surface. The existence of functional groups and the composition of the biodiesel obtained was analysed by FTIR and GC-MS. S/AlMCM-41 (80%) catalyst presented a high catalytic activity with maximum biodiesel conversion % when compared to other variants. The bio-ester produced from CFMO with S/AlMCM-41 (80%) catalyst possessed the higher calorific value of 50 MJ/kg and flashpoint of 153 °C and other properties analogous to the standard biodiesel. The engine performance was examined for biodiesel blends with neat diesel, where biodiesel blends performed better than neat diesel. The exhaust gas emission studies also highlighted that the obtained biodiesel showed emission characteristics similar to the standard biodiesel, whereas marginally higher emission for CO and CO2 of about 2.2 and 7.9% was reported.

Matched MeSH terms: Feathers
Characterization of keratin microparticles from feather biomass with potent antioxidant and anticancer activities

Sharma S, Gupta A, Chik SMST, Kee CG, Mistry BM, Kim DH, et al.

Int J Biol Macromol, 2017 Nov;104(Pt A):189-196.
PMID: 28596005 DOI: 10.1016/j.ijbiomac.2017.06.015

In the present study chicken feathers were hydrolyzed by chemical treatment in alkaline conditions. The pH value of feather hydrolyzed solution was amended accordingly the iso-electric precipitation. Two types of keratin microparticles KM1, KM2 were synthesized under acidic conditions at 3.5 and 5.5pH respectively. The synthesized keratin microparticles possessed uniform and round surface by scanning electron microscopy (SEM). The thermal degradation of microparticles were examined by thermogravimetry (TGA). Fourier transform infrared spectroscopy (FTIR) revealed that the extracted keratin retained the most of protein backbone. The microparticles were screened for their in vitro anticancer activities by SRB bioassay towards HeLa, SK-OV-3 and A549 cancer cell lines. Futhermore, their cytotoxicity towards healthy cell lines was analyzed having Malin Darby canine kidney (MDCK) cell lines along with in vitro antioxidant activity using DPPH and ABTS methods KM1 and KM2 showed 200.31±1.01 and 139.73±0.94, 214.16±0.29 and 153.92±0.61, 328.92±3.46 and 200.33±2.48μg/mL of IC50 levels against HeLa, SK-OV-3, and A549 cell lines, respectively. Moreover, KM1 and KM2 demonstrated significant antioxidant potency with IC50 levels 13.15 and 9.02μg/mL as well as 8.96 and 5.60μg/mL in DPPH and ABTS radical scavenging bioassay, respectively.

Matched MeSH terms: Feathers/chemistry*
Ultrasonic technology for value added products from feather keratin

Azmi NA, Idris A, Yusof NSM

Ultrason Sonochem, 2018 Oct;47:99-107.
PMID: 29908610 DOI: 10.1016/j.ultsonch.2018.04.016

Feather keratin is a biomass generated in excess from various livestock industries. With appropriate processing, it holds potential as a green source for degradable biopolymer that could potentially replace current fossil fuel based materials. Several processing methods have been developed, but the use of ultrasonication has not been explored. In this study, we focus on (i) comparing and optimizing the dissolution process of turkey feather keratin through sonication and conventional processes, and (ii) generating a biodegradable polymer material, as a value added product, from the dissolved keratin that could be used in packaging and other applications. Sonication of feather keratin in pure ionic liquids (ILs) and a mixture containing ILs and different co-solvents was conducted under different applied acoustic power levels. It was found that ultrasonic irradiation significantly improved the rate of dissolution of feather keratin as compared to the conventional method, from about 2 h to less than 20 min. The amount of ILs needed was also reduced by introducing a suitable co-solvent. The keratin was then regenerated, analyzed and characterized using various methods. This material holds the potential to be reused in various appliances.

Matched MeSH terms: Feathers/chemistry*
Recovery of value-added glycopeptides from edible bird's nest (EBN) co-products: enzymatic hydrolysis, physicochemical characteristics and bioactivity

Ling JWA, Chang LS, Babji AS, Lim SJ

J Sci Food Agric, 2020 Oct;100(13):4714-4722.
PMID: 32468613 DOI: 10.1002/jsfa.10530

BACKGROUND: Processing of edible bird's nest (EBN) requires extensive washing to remove impurities and produces huge amounts of EBN co-products, which contain mainly feathers with glycoproteins attached, which are usually discarded. This study was conducted to recover the valuable EBN glycoproteins from the waste material. Enzymatic hydrolysis was applied to recover EBN glycopeptides from EBN co-products (EBNcoP ) and processed cleaned EBN (EBNclean ) was used as control, which were then freeze-dried into EBN hydrolysates (EBNhcoP and EBNhclean , respectively).
RESULTS: The recovery yield for EBNhclean and EBNhcoP were 89.09 ± 0.01% and 47.64 ± 0.26%, respectively, indicating nearly 50% of glycopeptide can be recovered from the waste material. Meanwhile, N-acetylneuraminic acid, a major acid sugar in EBN glycoproteins, of EBNhcoP increased by 229% from 58.6 ± 3.9 to 192.9 ± 3.1 g kg-1 , indicating the enzymatic hydrolysis removed impurities and thus enhanced the N-acetylneuraminic acid content. Total soluble protein was more than 330 g kg-1 for all the samples. Colour parameter showed that hydrolysate samples have greater L* (lightness) values. Chroma result indicates the intensity of all the samples were low (

Matched MeSH terms: Feathers/chemistry
The use of feather as an indicator for heavy metal contamination in house crow (Corvus splendens) in the Klang area, Selangor, Malaysia

Janaydeh M, Ismail A, Zulkifli SZ, Bejo MH, Aziz NA, Taneenah A

Environ Sci Pollut Res Int, 2016 Nov;23(21):22059-22071.
PMID: 27541152

The Klang area of Peninsular Malaysia has experienced rapid industrial growth with intense activities, which can increase the concentration of pollutants in the environment that significantly impact on habitats and the human health. The purpose of this study was to determine the levels of selected heavy metals (Cu, Zn, Ni, Fe, and Pb) in the heart, lung, brain, liver, kidney, muscle tissues, and feathers of house crow, Corvus splendens, in Klang, Peninsular Malaysia. House crow samples were collected from the Klang area through the Department of Public Health at Majlis Perbandaran Klang. Quantitative determination of heavy metals was carried out using atomic absorption spectrophotometer (AAS). The result shows the presence of heavy metals in all biological samples of house crows. For heavy metals in all the house crow tissues analyzed, Fe concentrations were the highest, followed by those of Zn, Cu, Pb, and Ni. The feathers and kidney accumulated high concentrations of Pb, whereas the liver accumulated high concentrations of essential heavy metals (Fe > Zn > Cu > Ni). Significant variations were also detected in the concentrations of Pb among adult and juvenile and male and female bird samples. The results also revealed significant positive correlations between Pb metal concentration in the breast feathers and all internal organs. Accumulation of toxic heavy metals in feathers reflected storing and elimination processes, while the accumulation of toxic heavy metals in the kidney can be consequential to chronic exposure. The present study clearly shows the usefulness of house crow breast feather as a suitable indicator for heavy metal accumulation in the internal organs of house crows in the Klang area.

Matched MeSH terms: Feathers/chemistry*
Fulltext Non-invasive sex identification of the white-bellied sea eagle (Haliaeetus leucogaster) through genetic analysis of feathers

Naim DM, Nor SA, Baharuddin MH

Genet. Mol. Res., 2011;10(4):2505-10.
PMID: 22009862 DOI: 10.4238/2011.October.13.7

The white-bellied sea eagle, Haliaeetus leucogaster, displays reversed sexual size dimorphism and is monomorphic for adult plumage coloration. Early attempts to identify sex in sexually monomorphic birds were based on morphological or chromosomal characters, but since avian W-specific DNA sequences were identified, PCR amplification has become commonly used for molecular sexing. We used a PCR test employing primers that amplify two homologous fragments of both the CHD-W gene, unique to females, and the CHD-Z gene, occurring in both sexes. This test was applied to five individuals of H. leucogaster from the Malacca Zoo and to male and female domestic chickens, Gallus domesticus, for comparison. All individuals were sexed successfully with high reproducibility. We conclude that this PCR-based test with feathers as the DNA source is a reliable sexing method for H. leucogaster. This sexing technique is objective and non-invasive and could be used to test sex ratio theories, as well as to help improve conservation and management actions for captive breeding program of this species in Malaysia.

Matched MeSH terms: Feathers*
Microsporum fulvum IBRL SD3: as novel isolate for chicken feathers degradation

Darah I, Nur-Diyana A, Nurul-Husna S, Jain K, Lim SH

Appl Biochem Biotechnol, 2013 Dec;171(7):1900-10.
PMID: 24013862 DOI: 10.1007/s12010-013-0496-4

Keratinous wastes have increasingly become a problem and accumulate in the environment mainly in the form of feathers, generated mainly from a large number of poultry industries. As keratins are very difficult to degrade by general proteases, they pose a major environmental problem. Therefore, microorganisms which would effectively degrade keratins are needed for recycling such wastes. A geophilic dermatophyte, Microsporum fulvum IBRL SD3 which was isolated from a soil sample collected from a chicken feather dumping site using a baiting technique, was capable to produce keratinase significantly. The crude keratinase was able to degrade whole chicken feathers effectively. The end product of the degradation was protein that contained essential amino acids and may have potential application in animal feed production. Thus, M. fulvum could be a novel organism to produce keratinase for chicken feathers degradation.

Matched MeSH terms: Feathers/metabolism*
Toxicity of cadmium and lead in Gallus gallus domesticus assessment of body weight and metal content in tissues after metal dietary supplements

Abduljaleel SA, Shuhaimi-Othman M

Pak J Biol Sci, 2013 Nov 15;16(22):1551-6.
PMID: 24511699

The influence of dietary cadmium on the accumulation and effects of dietary lead, examined in chicken. This experiment was conducted to investigate the toxic effects of dietary Cd and Pb on chick's body weight and organ, content of the tissues of these two metals was also detected. One day age chicks of Gallus gallus domesticus fed diet supplemented with 25, 50, 100 ppm of Cd, second group exposure to 300, 500, 1000 ppm of Pb in feed daily during 4 weeks. The control groups were fed without supplementation of metals. The concentrations of Cd and Pb resulted in increased of Cd and Pb content in liver, gizzard and muscle. While Cd 100 ppm and Pb 1000 ppm were increased metals content in feather. Body weight of chicks was not influenced by Cd treatment. In contrary Pb treatment was significantly (p < 0.05) decreased body weight of chicks after dietary treatment. On the other hand, Liver weigh in chicks was significantly (p < 0.05) decreased after Cd and Pb treatments.

Matched MeSH terms: Feathers/drug effects; Feathers/metabolism
Fulltext The positive expression of genotype VII Newcastle disease virus (Malaysian isolate) in Japanese quails (Coturnix coturnix japonica)

Mazlan LF, Bachek NF, Mahamud SNA, Idris LH, Wei TS, Omar AR, et al.

Vet World, 2017 May;10(5):542-548.
PMID: 28620260 DOI: 10.14202/vetworld.2017.542-548

AIM: Genotype VII Newcastle disease virus (NDV) is the most predominant NDV strains that circulating in Malaysia; thus, this study was aimed to determine the susceptibility of Japanese quails toward genotype VII NDV. Clinical signs, gross pathological lesions of organs, positive detection of virus in organs and cloacal swabs, as well as the expression of the antibody titer, were used as parameters to assess the susceptibility of Japanese quails following infection of genotype VII NDV.
MATERIALS AND METHODS: About 20 quails were divided into three groups (n=8 for Groups A and B; n=4 for the control group). The quails in the Groups A and B were infected via intraocular route with 0.03 ml of 103.5 ELD50 and 107.0 ELD50 of NDV strain IBS 002, respectively, while the control group received 1× phosphate-buffered saline. Cloacal swabs and necropsy were taken on day 7 post-infection for all quails were subjected to one-step reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR) for detection of virus and examination for gross pathological lesion, respectively. Blood serums of infected quails were taken on day 10, 14, and 21 post-day infections and were subjected for hemagglutination inhibition (HI) assay.
RESULTS: Depression and ruffled feathers, trachea rales, leg paralysis, and torticollis were shown in some of the quails in both infected groups. Based on statistical analysis, there was no significant difference (p>0.05) in clinical signs between the infected groups. The results for RT-qPCR were found to be negative for all groups, and no gross pathological lesions of organs observed for quails in both infected groups. Trachea, proventriculus, and cecal tonsil were taken for the detection of NDV by RT-qPCR, and some of the organ samples showed positive detection of virus in both infected groups. HI assay showed an increase in mean titers of antibody across time and between infected groups.
CONCLUSION: In summary, Japanese quails are susceptible to genotype VII NDV based on parameters assessed.

Matched MeSH terms: Feathers
Fulltext Avian polyomavirus: a recent update

Padzil, F., Mariatulqabtiah, A. R., Abu, J.

Jurnal Veterinar Malaysia, 2017;29(2):9-13.
MyJurnal

Avian polyomavirus disease is among the most common viral diseases of domesticated exotic birds as such in psittacine families. Caused by avian polyomavirus (APV) which possess a circular, double-stranded DNA which encodes for major structural virus protein 1 (VP1) and minor structural proteins VP2, VP3 and VP4, the disease is also known as Budgerigar fledgling disease polyomavirus (BFPyV), Papovavirus, and Psittacine polyomavirus. Infections from APV may lead to cutaneous haemorrhage, abdominal distension, feather abnormalities and even death. The APV virus has a broad avian host range and is known to cause acute chronic disease in several psittacine birds such as parrot, cockatoo, macaw, and budgerigar. The current status of APV epidemiology globally has not been fully recorded. Only the studies of the virus and disease caused within several countries are used as references, and few were done together with detection of beak and feather disease virus. Despite the common occurrence of APV among bird breeders in Malaysia, a very limited study has been done to evaluate the prevalence status of APV in Malaysia. In this review, we wish to disseminate knowledge, particularly to pet owners and bird breeders, on APV characterisations, its updated occurrence worldwide and prevention strategies. This information may be useful to trigger in depth study on the epidemiology of disease and better management practises among breeders.

Matched MeSH terms: Feathers
Fulltext Do wild-caught urban house sparrows show desensitized stress responses to a novel stressor?

Salleh Hudin N, Teyssier A, Aerts J, Fairhurst GD, Strubbe D, White J, et al.

Biol Open, 2018 Jun 15;7(6).
PMID: 29632231 DOI: 10.1242/bio.031849

While urbanization exposes individuals to novel challenges, urban areas may also constitute stable environments in which seasonal fluctuations are buffered. Baseline and stress-induced plasma corticosterone (cort) levels are often found to be similar in urban and rural populations. Here we aimed to disentangle two possible mechanisms underlying such pattern: (i) urban environments are no more stressful or urban birds have a better ability to habituate to stressors; or (ii) urban birds developed desensitized stress responses. We exposed wild-caught urban and rural house sparrows (Passer domesticus) to combined captivity and diet treatments (urban versus rural diet) and measured corticosterone levels both in natural tail feathers and in regrown homologous ones (cortf). Urban and rural house sparrows showed similar cortf levels in the wild and in response to novel stressors caused by the experiment, supporting the growing notion that urban environments are no more stressful during the non-breeding season than are rural ones. Still, juveniles and males originating from urban populations showed the highest cortf levels in regrown feathers. We did not find evidence that cortf was consistent within individuals across moults. Our study stresses the need for incorporating both intrinsic and environmental factors for the interpretation of variation in cortf between populations.

Matched MeSH terms: Feathers
Fulltext Effective production of keratinase by gellan gum-immobilised Alcaligenes sp. AQ05-001 using heavy metal-free and polluted feather wastes as substrates

Yusuf I, Ahmad SA, Phang LY, Yasid NA, Shukor MY

3 Biotech, 2019 Jan;9(1):32.
PMID: 30622870 DOI: 10.1007/s13205-018-1555-x

The ability of gellan gum-immobilised cells of the heavy metal-tolerant bacterium Alcaligenes sp. AQ05-001 to utilise both heavy metal-free and heavy metal-polluted feathers (HMPFs) as substrates to produce keratinase enzyme was studied. Optimisation of the media pH, incubation temperature and immobilisation parameters (bead size, bead number, gellan gum concentration) was determined for the best possible production of keratinase using the one-factor-at-a-time technique. The results showed that the immobilised cells could tolerate a broader range of heavy metal concentrations and produced higher keratinase activity at a gellan gum concentration of 0.8% (w/v), a bead size of 3 mm, bead number of 250, pH of 8 and temperature of 30 °C. The entrapped bacterium was used repeatedly for ten cycles to produce keratinase using feathers polluted with 25 ppm of Co, Cu and Ag as substrates without the need for desorption. However, its inability to tolerate/utilise feathers polluted with Hg, Pb, and Zn above 5 ppm, and Ag and Cd above 10 ppm resulted in a considerable decrease in keratinase production. Furthermore, the immobilised cells could retain approximately 95% of their keratinase production capacity when 5 ppm of Co, Cu, and Ag, and 10 ppm of As and Cd were used to pollute feathers. When the feathers containing a mixture of Ag, Co, and Cu at 25 ppm each and Hg, Ni, Pb, and Zn at 5 ppm each were used as substrates, the immobilised cells maintained their operational stability and biological activity (keratinase production) at the end of 3rd and 4th cycles, respectively. The study indicates that HMPF can be effectively utilised as a substrate by the immobilised-cell system of Alcaligenes sp. AQ05-001 for the semi-continuous production of keratinase enzyme.

Matched MeSH terms: Feathers

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