Low levels of chicken body louse (Menacanthus stramineus) infestations affect chicken welfare in a cage-free housing system.

BACKGROUND: The chicken body louse is an obligate ectoparasite of domestic chickens. Chicken body lice feed on feathers, and infestation with this louse is linked to decreases in egg production, hen weight, and feed conversion efficiency. However, it is unknown how chicken body lice impact egg-laying chickens in cage-free environments. Welfare and behavior metrics were collected from flocks of egg-laying chickens either infested with chicken body lice or left uninfested. METHODS: In two trials, two flocks of cage-free commercial egg-laying chickens were infested with chicken body lice or maintained as uninfested controls. At three timepoints, behavior and welfare of all chickens was measured. On-animal sensors were used to quantify pecking, preening, and dustbathing behavior. Other animal-based welfare metrics included recording comb wounds and skin lesions. RESULTS: Birds infested with chicken body lice exhibited significantly more preening behaviors than uninfested birds, even at low louse levels. Moderate or severe skin lesions were detected on birds that were moderately infested with chicken body lice while skin lesions were never detected on uninfested birds. CONCLUSIONS: The welfare of chickens was impacted by the chicken body louse, a chewing louse that primarily feather feeds. Evidence of skin lesions on infested birds suggests that lice may cause more damage to birds than previously thought, and further evaluation of louse economic damage is necessary.

Spontaneous immunological activities in the target tissue of vitiligo-prone Smyth and vitiligo-susceptible Brown lines of chicken.

Introduction: Vitiligo is an acquired de-pigmentation disorder characterized by the post-natal loss of epidermal melanocytes (pigment-producing cells) resulting in the appearance of white patches in the skin. The Smyth chicken is the only model for vitiligo that shares all the characteristics of the human condition including: spontaneous post-natal loss of epidermal melanocytes, interactions between genetic, environmental and immunological factors, and associations with other autoimmune diseases. In addition, an avian model for vitiligo has the added benefit of an easily accessible target tissue (a growing feather) that allows for the repeated sampling of an individual and thus the continuous monitoring of local immune responses over time. Methods: Using a combination of flow cytometry and gene expression analyses, we sought to gain a comprehensive understanding of the initiating events leading to expression of vitiligo in growing feathers by monitoring the infiltration of leukocytes and concurrent immunological activities in the target tissue beginning prior to visual onset and continuing throughout disease development. Results: Here, we document a sequence of immunologically significant events, including characteristic rises in infiltrating B and αß T cells as well as evidence of active leukocyte recruitment and cell-mediated immune activities (CCL19, IFNG, GZMA) leading up to visual vitiligo onset. Examination of growing feathers from vitiligo-susceptible Brown line chickens revealed anti-inflammatory immune activities which may be responsible for preventing vitiligo (IL10, CTLA4, FOXP3). Furthermore, we detected positive correlations between infiltrating T cells and changes in their T cell receptor diversity supporting a T cell-specific immune response. Conclusion: Collectively, these results further support the notion of cell-mediated immune destruction of epidermal melanocytes in the pulp of growing feathers and open new avenues of study in the vitiligo-prone Smyth and vitiligo-susceptible Brown line chickens.

Morphological variation of tail bone among two chicken breeds and their F1 progeny.

Fancy breeds of Japanese indigenous chicken display extensive morphological diversity, particularly in tail feathers. Although marked differences in tail and bone traits have been reported between Tosa-jidori (wild type) and Minohikichabo (rich type) breeds, little is known about the pattern of genetic inheritance in cross experiments. Therefore, this study aimed to investigate the strain and sex effects, and inheritance patterns, in the morphometric variation of pygostyle bones among Tosa-jidori, Minohikichabo, and their F1 hybrids. Five morphological traits, angle of the apex of the pygostyle, pygostyle length, margo cranialis length, tail feather number, and body weight, were evaluated at the adult stage. A significant strain difference was detected in all traits, whereas significant sex differences were observed in only three traits, but not in the angle of the apex of the pygostyle and tail feather number. In F1 hybrids, the angle of the apex of the pygostyle was significantly different to that of Tosa-jidori but not that of Minohikichabo, whereas the pygostyle length and tail number of F1 hybrids were significantly different from those of Minohikichabo but not those of Tosa-jidori. A significant heterosis effect was found in the margo cranialis length and body weight. All five traits showed nonadditive inheritance patterns but varied in each trait between partial dominance (angle of the apex of pygostyle), full dominance (pygostyle length and tail feather number), and over-dominance (margo cranialis length and body weight). Interestingly, different patterns of genetic inheritance in the F1 hybrid were observed at different locations, even within the same pygostyle bone. Using the Japanese indigenous chicken model, these results provide a substantial step toward understanding the genetic architecture of morphology in chickens.

Proof of concept evidence that stable isotopes of carbon, nitrogen and sulphur may identify individual kittiwakes breeding in different colonies.

RATIONALE: Carbon, nitrogen and sulphur stable isotopes in feathers grown by seabirds while breeding reflect the local isoscape and diet in the vicinity of the colony, so may make it possible to discriminate individual birds from different colonies. METHODS: Black-legged kittiwake Rissa tridactyla inner primary feathers from two colonies about 350 km apart in the North Sea were used to test whether δ13C, δ15N and δ34S differed between individuals from the two colonies. Feather tips cut from breeding birds caught at nests were compared with tips of moulted feathers (grown 1 year earlier) found on the ground. RESULTS: Isotopic compositions showed no overlap between the two colonies in δ13C, δ15N or δ34S in tips of newly-grown feathers sampled from breeding adult kittiwakes. There was some overlap in δ13C, δ15N and δ34S from moulted feathers, but discriminant analysis allowed >90% of individuals to be assigned to their colony. In five of six comparisons, mean isotopic compositions were the same in new and moulted feathers but not for δ34S at one of the two colonies. CONCLUSIONS: This study has demonstrated for the first time that stable isotopes in inner primary feathers of kittiwakes can allow accurate identification of the breeding colony of individual birds from two different colonies within the North Sea. Further research is required to determine if this method can be applied with greater spatial resolution and to a larger number of colonies.

Seabirds reveal mercury distribution across the North Atlantic.

Mercury (Hg) is a heterogeneously distributed toxicant affecting wildlife and human health. Yet, the spatial distribution of Hg remains poorly documented, especially in food webs, even though this knowledge is essential to assess large-scale risk of toxicity for the biota and human populations. Here, we used seabirds to assess, at an unprecedented population and geographic magnitude and high resolution, the spatial distribution of Hg in North Atlantic marine food webs. To this end, we combined tracking data of 837 seabirds from seven different species and 27 breeding colonies located across the North Atlantic and Atlantic Arctic together with Hg analyses in feathers representing individual seabird contamination based on their winter distribution. Our results highlight an east-west gradient in Hg concentrations with hot spots around southern Greenland and the east coast of Canada and a cold spot in the Barents and Kara Seas. We hypothesize that those gradients are influenced by eastern (Norwegian Atlantic Current and West Spitsbergen Current) and western (East Greenland Current) oceanic currents and melting of the Greenland Ice Sheet. By tracking spatial Hg contamination in marine ecosystems and through the identification of areas at risk of Hg toxicity, this study provides essential knowledge for international decisions about where the regulation of pollutants should be prioritized.

Fabrication of silver nanoparticles decorated on sodium alginate microbeads enriched with keratin and investigation of its catalytic and antioxidant activity.

In this study, an environmentally friendly, effective, easily synthesizable and recoverable nano-sized catalyst system (Ag@NaAlg-keratin) was designed by decorating Ag nanoparticles on microbeads containing sodium alginate (NaAlg) and keratin obtained from goose feathers. The structure, morphology and crystallinity of the Ag@NaAlg-keratin nanocatalyst were evaluated by XRD, FT-IR, FE-SEM, EDS/EDS mapping and TEM analyses. Catalytic ability of designed Ag@NaAlg-keratin nanocatalyst was then investigated against 4-nitrophenol (4-NP) and methyl orange (MO) reductions. Ag@NaAlg-keratin nanocatalyst effectively reduced 4-NP in 6 min and MO in 5 min, with rate constants of 0.17 min-1 and 0.16 min-1, respectively. Additionally, activation energies (Ea) were found as 39.8 kJ/mol for 4-NP and 37.9 kJ/mol for MO. Performed recyclability tests showed that the Ag@NaAlg-keratin nanocatalyst was easily recovered due to its microbead form and successfully reused five times, maintaining both its activity and structure. Furthermore, antioxidant activity of Ag@NaAlg-keratin nanocatalyst was the highest (73.16 %).

Interaction of barn owl leading edge serrations with freestream turbulence.

The silent flight of barn owls is associated with wing and feather specialisations. Three special features are known: a serrated leading edge that is formed by free-standing barb tips which appears as a comb-like structure, a soft dorsal surface, and a fringed trailing edge. We used a model of the leading edge comb with 3D-curved serrations that was designed based on 3D micro-scans of rows of barbs from selected barn-owl feathers. The interaction of the flow with the serrations was measured with Particle-Image-Velocimetry in a flow channel at uniform steady inflow and was compared to the situation of inflow with freestream turbulence, generated from the turbulent wake of a cylinder placed upstream. In steady uniform flow, the serrations caused regular velocity streaks and a flow turning effect. When vortices of different size impacted the serrations, the serrations reduced the flow fluctuations downstream in each case, exemplified by a decreased root-mean-square value of the fluctuations in the wake of the serrations. This attenuation effect was stronger for the spanwise velocity component, leading to an overall flow homogenization. Our findings suggest that the serrations of the barn owl provide a passive flow control leading to reduced leading-edge noise when flying in turbulent environments.

Bioenergy production from chicken feather waste by anaerobic digestion and bioelectrochemical systems.

BACKGROUND: Poultry feather waste has a potential for bioenergy production because of its high protein content. This research explored the use of chicken feather hydrolysate for methane and hydrogen production via anaerobic digestion and bioelectrochemical systems, respectively. Solid state fermentation of chicken waste was conducted using a recombinant strain of Bacillus subtilis DB100 (p5.2). RESULTS: In the anaerobic digestion, feather hydrolysate produced maximally 0.67 Nm3 CH4/kg feathers and 0.85 mmol H2/day.L concomitant to COD removal of 86% and 93%, respectively. The bioelectrochemical systems used were microbial fuel and electrolysis cells. In the first using a microbial fuel cell, feather hydrolysate produced electricity with a maximum cell potential of 375 mV and a current of 0.52 mA. In the microbial electrolysis cell, the hydrolysate enhanced the hydrogen production rate to 7.5 mmol/day.L, with a current density of 11.5 A/m2 and a power density of 9.26 W/m2. CONCLUSIONS: The data indicated that the sustainable utilization of keratin hydrolysate to produce electricity and biohydrogen via bioelectrical chemical systems is feasible. Keratin hydrolysate can produce electricity and biofuels through an integrated aerobic-anaerobic fermentation system.

Preening cups in duck housing are associated with an increase in central dopamine activity that suggests a negative affective state.

Preening cups are a form of environmental enrichment that provides Pekin ducks a semi-open water source to express their natural behaviors. We recently observed that preening cups may increase feather pecking behaviors in ducks. Thus, we set out to determine if this form of enrichment can impact the affective state of Pekin ducks. To accomplish this goal, we evaluated the effect of preening cups on serotonin (5-HT) and dopamine (DA) turnover via mass spectrometry and their respective synthetic enzyme gene expression via qRT-PCR. Our study investigated the link between aggressive pecking with levels and activity of brain 5-HT and DA. Brain 5-HT and DA levels and activity have been established for decades to be associated with affective states. Grow-out Pekin ducks (n = 260) were housed at Purdue and raised per industry standards. On day 18, brains were collected from ducks in pens before preening cups were placed (PRE, n = 6) and, again on day 43, in pens with (PC, n = 6) and without (CON, n = 6) preening cups. Brains were dissected into right and left halves, then further microdissected into 4 brain areas: caudal mesencephalon (CM), rostral mesencephalon (RM), diencephalon (DI), and forebrain (FB). The right hemisphere was used for mass spectrometry to determine the neurotransmitter concentration (ng/mg of tissue) and those concentrations were applied to neurotransmitter turnover equations. There were no differences across treatments for 5-HT turnover in any brain area. There were differences in DA turnover across age (P = 0.0067) in the CM and across treatments (P = 0.003) in the RM. The left hemisphere of the brain was used to perform qRT-PCR on the genes of 5-HT and DA production enzymes. Within the CM, day 43 duck brains had increased (P = 0.022) tryptophan hydroxylase and tyrosine hydroxylase relative mRNA levels. All other brain areas showed no differences. Our data suggest that ducks housed with preening cups and that showed increased feather pecking are associated with increased brain DA activity. The increased DA in the brain may lead to a predisposition for increased aggression in the form of feather pecking.

Anatomy, development and regeneration of zebrafish elasmoid scales.

Vertebrate skin appendages - particularly avian feathers and mammalian hairs, glands and teeth - are perennially useful systems for investigating fundamental mechanisms of development. The most common type of skin appendage in teleost fishes is the elasmoid scale, yet this structure has received much less attention than the skin appendages of tetrapods. Elasmoid scales are thin, overlapping plates of partially mineralized extracellular matrices, deposited in the skin in a hexagonal pattern by a specialized population of dermal cells in cooperation with the overlying epidermis. Recent years have seen rapid progress in our understanding of elasmoid scale development and regeneration, driven by the deployment of developmental genetics, live imaging and transcriptomics in larval and adult zebrafish. These findings are reviewed together with histological and ultrastructural approaches to understanding scale development and regeneration.

Dorsal and Ventral Plumage Coloration Evolve as Distinct Modules with Different Environmental Correlations.

AbstractMany animals exhibit contrast between their dorsal coloration and their ventral coloration. If selection acts differently on dorsal versus ventral coloration, ancestral covariance between these traits should break down, eventually leading to independent modules of trait evolution. Here, we compare the evolution of feather color across body regions for a clade of Australasian songbirds (Meliphagoidea). We find evidence for three modules of covarying color regions. Among these modules, ventral feathers evolve with high lability, evolving at three times the rate of dorsal plumage and 20 times the rate of flight feathers. While both dorsal plumage and ventral plumage are darker in areas with more precipitation and vegetation, we find that dorsal plumage is twice as similar to colors in satellite photos of background substrates. Overall, differential selection on ventral and dorsal colors likely maintains these as distinct modules over evolutionary timescales-a novel explanation for dorsoventral contrast in pigmentation.

Chemical Profiles Differ between Communal Breeding Groups in a Highly Social Bird.

AbstractGregarious species must distinguish group members from nongroup members. Olfaction is important for group recognition in social insects and mammals but rarely studied in birds, despite birds using olfaction in social contexts from species discrimination to kin recognition. Olfactory group recognition requires that groups have a signature odor, so we tested for preen oil and feather chemical similarity in group-living smooth-billed anis (Crotophaga ani). Physiology affects body chemistry, so we also tested for an effect of egg-laying competition, as a proxy for reproductive status, on female chemical similarity. Finally, the fermentation hypothesis for chemical recognition posits that host-associated microbes affect host odor, so we tested for covariation between chemicals and microbiota. Group members were more chemically similar across both body regions. We found no chemical differences between sexes, but females in groups with less egg-laying competition had more similar preen oil, suggesting that preen oil contains information about reproductive status. There was no overall covariation between chemicals and microbes; instead, subsets of microbes could mediate olfactory cues in birds. Preen oil and feather chemicals showed little overlap and may contain different information. This is the first demonstration of group chemical signatures in birds, a finding of particular interest given that smooth-billed anis live in nonkin breeding groups. Behavioral experiments are needed to test whether anis can distinguish group members from nongroup members using odor cues.

Male starling floaters preferentially visit nests of males with reduced resource holding potential.

Floaters are sexually mature individuals that are not able to reproduce by defending breeding resources. Floaters often visit active nests, probably to gather public information or to compete for a nesting site. We tested the hypothesis that floaters preferentially prospect nests in which they have a better chance of taking over, and that they do so by assessing the owners' resource holding potential (RHP). We manipulated the flight capacity of male and female breeders in a population of spotless starlings (Sturnus unicolor) by clipping two flight feathers per wing before egg laying, thus increasing their wing-load and likely impairing their condition. We subsequently monitored breeder and floater activity by means of transponder readers during the nestling period. We found that nests owned by wing-clipped males were visited by a greater number of male floaters than control nests. This effect was absent in the case of wing-clipped females. The number of male floaters also increased with increasing nestling age and number of parental visits. The experiment shows that male floaters preferentially prospect nests in which the owner shows a reduced RHP, a strategy that likely allows them to evict weak owners and take over their nests for future reproductive attempts.

Keratin-based bioplastics extracted from chicken feathers: Effect of chitosan concentration on the structural, chemical bonding, and mechanical properties of bioplastics.

Keratin was synthesized by alkaline hydrolysis from chicken feathers and then continue by casting method for producing bioplastics with additional various amounts of chitosan as a filler, polyvinyl alcohol (PVA) and glycerol as a plasticizer. The main purpose is analysis the effect of chitosan on the structural properties using quantitative analysis of X-ray diffraction (XRD) spectra, chemical bonding by Fourier transforms infrared (FTIR) spectra, and mechanical properties by texture analyser to the keratin-based bioplastics. Biodegradation of bioplastics was analysed from the loss of weight by burying in the soil. It's found that, the additional of chitosan (0 %, 2 %, 5 %, and 8 %) increased the crystallinity of bioplastics by 11.83 %, 11.12 %, 18.99 %, and 17.03 %, respectively, but decreasing tensile strength and elasticity of bioplastics. Degradation of bioplastic keratin-based shows that the addition of chitosan can reduce the degradation time which is directly proportional to the loss of CO bonds. The highest degradation rate is 89.29 % in 49 days for keratin-based bioplastics with 8 % chitosan, indicated that high potential for future production.

Peptide recovery from chicken feather keratin and their anti-biofilm properties against methicillin-resistant Staphylococcus aureus (MRSA).

Bacteria have the potential to adhere to abiotic surfaces, which has an undesirable effect in the food industry because they can survive for sustained periods through biofilm formation. In this study, an antibacterial peptide (ABP), with a molecular mass of 3861 Da, was purified from hydrolyzed chicken feathers using a locally isolated keratinolytic bacterium, namely Rhodococcus erythropolis, and its antibacterial and antibiofilm potential were investigated against planktonic and biofilm cells of Methicillin-Resistant Staphylococcus Aureus (MRSA). The results demonstrated that purified ABP showed the growth inhibition of MRSA cells with the minimum inhibitory concentration (MIC) of 45 µg/ml and disrupted MRSA biofilm formation at a concentration of 200 ug/ml, which results were confirmed by scanning electron micrograph (SEM). Moreover, the secondary structures of the peptide were assessed as part of the FTIR analysis to evaluate its mode of action. ExPASy tools were used to predict the ABP sequence, EPCVQUQDSRVVIQPSPVVVVTLPGPILSSFPQNTA, from a chicken feather keratin sequence database following in silico digestion by trypsin. Also, ABP had 54.29% hydrophobic amino acids, potentially contributing to its antimicrobial activity. The findings of toxicity prediction of the peptide by the ToxinPred tool revealed that ABP had non-toxic effects. Thus, these results support the potential of this peptide to be used as an antimicrobial agent for the treatment or prevention of MRSA biofilm formation in feed, food, or pharmaceutical applications.

Comparison of gamithromycin residue depletion in yellow-feather and white-feather broilers after one single subcutaneous injection.

This study aimed to compare the residue depletion of gamithromycin in yellow-feather and white-feather broilers, using Sanhuang and Arbor Acres chickens as typical examples, respectively. Each breed (54 chickens) received a single subcutaneous dose of gamithromycin at 7.5 mg/kg bodyweight (BW). Tissues, including muscle, skin + fat, liver, kidney, and injection site, were collected at 6 h, 3, 5, 7, 10, 14, 21, 28, and 35 d postdrug administration. Gamithromycin concentrations in these tissues were determined using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The kinetics of gamithromycin were analyzed in different tissues using a noncompartmental method in the Phoenix software. Differences were observed in gamithromycin concentrations and kinetic characteristics in both breeds of chickens, with higher residue concentrations and longer residue times found in yellow-feathered broilers. In Sanhuang broilers, the elimination rates of gamithromycin followed this order: injection site > muscle > liver > kidney > skin + fat. The corresponding elimination half-lives (t1/2λzs) in these samples were 1.22, 1.30, 1.71, 2.04, and 2.52 d, respectively. In contrast, in Arbor Acres broilers, a different order was noted: muscle > injection site > kidney > liver > skin + fat, with corresponding t1/2λzs of 1, 1.23, 1.88, 1.93, and 2.21 d, respectively. These differences may be related to variations in pigments in various tissues of chickens of the 2 breeds. However, further investigations are warranted to discern the underlying reasons.

Mercury in the feathers of Golden eagle (Aquila chrysaetos) from Western Carpathian, Slovakia.

In this study, mercury (Hg) concentrations were detected in feathers of golden eagle (Aquila chrysaetos), a bird that typically inhabits alpine and forest areas. The mercury rates in feathers were compared in two groups of eagles: first, estimated home range (breeding, hunting, etc.) was located only in forest and lowland meadow habitats; second, the home range also included alpine habitats-rocks and meadows. Consequently, mercury concentration based on the feather typology were observed and the mercury levels in feathers were also compared among different Slovak Western Carpathian districts. It was found that there was no significant difference between groups classified by elevation level, which we attribute to the fact that eagle hunting territories are broad, so that alpine-dwelling and forest-dwelling eagles do not only reflect the pollution of the environments they typically inhabit. Non-significant differences were found also within different feather types, which means that the type of feather is not crucial for tracking mercury in eagle feathers. As the measurement of feather appears to be a simple and non-invasive method, the detection of non-significant differences in diverse types of golden eagle feathers provides useful knowledge for the future environment monitoring. The average mercury concentration measured in eagle samples was lower than the mercury concentration causing health complications among birds of prey. Our assumption that due to past mining activity in the Spis region, the highest concentration in this region would be observed was confirmed.

Feather meal processing methods impact the production parameters, blood biochemical indices, gut function, and hepatic enzyme activity in broilers.

This study investigated the effects of feather meal (FM) processing methods on production parameters, blood biochemical indices, intestinal morphology, digestive and hepatic enzyme activities, and gastrointestinal tract pH and microflora of broilers. A total of 480-d-old male broilers were used for 42 d in a completely randomized design with eight treatments and five replicates (12 chicks/replicate). Treatments were 1) a control diet (without FM), 2) a diet containing 4% raw FM (RFM), 3) a diet containing 4% processed FM (PFM) by autoclave (Au-PFM), 4) a diet containing 4% fermented FM (FFM) by Bacillus licheniformis (Bl-FFM), 5) a diet containing 4% FFM by Bacillus subtilis (Bs-FFM), 6) a diet containing 4% FFM by Aspergillus niger (An-FFM), 7) a diet containing 4% FFM by B. licheniformis + B. subtilis + A. niger (Co-FFM), and 8) a diet containing 4% PFM by an enzyme (En-PFM). Results showed that in the FFMs the contents of ash, ether extract, total volatile nitrogen, and amino acids including Lys, Met, Thr, Trp, His, Leu, Gly, Ile, Phe, and Tyr increased (P < 0.05), while crude fiber, crude protein, and dry matter content decreased (P < 0.05). Compared with the control, the Co-FFM diet had no significant differences (P > 0.05) in total body weight gain (2,827 vs. 2,791 g/chick), total feed intake (5,018 vs. 4,991 g/chick), European production efficiency factor (375 vs. 377), European Broiler Index (371 vs. 371), and feed conversion ratio (1.77 vs. 1.78 g/g). Feeding FFM decreased (P < 0.05) serum total cholesterol (1.46-fold), triglyceride (1.61-fold), very low-density lipoprotein cholesterol (1.61-fold), and low-density lipoprotein cholesterol (2.27-fold) compared to the control. Also, FFM increased (P < 0.05) villus height (1,045 to 1,351, 661 to 854, and 523 to 620 µm), and villus height to crypt depth ratio (6.15 to 8.45, 4.55 to 7.04, and 4.27 to 5.45), in the duodenum, jejunum, and ileum, respectively, compared to the control. Compared to the control, the Co-FFM diet increased (P < 0.05) protease (34, 39, and 45 %) in the pancreas, duodenum, and jejunum, as well as amylase (73, and 97 %) activities in the duodenum, and jejunum, respectively. Diets containing FFM reduced (P < 0.05) pH in the crop, gizzard, and ileum, and decreased (P < 0.05) Escherichia coli (6.12 to 5.70) count in ileum compared to the control. The Co-FFM diet increased (P < 0.05) lactic acid bacteria count in crop (6.77 to 7.50) and ileum (6.94 to 7.73), also decreased (P < 0.05) coliforms (6.31 to 5.75) count in ileum compared to the control. In conclusion, FM fermentation, particularly Co-FFM, improves the nutritional value of FM, converting it into a decent source of dietary protein for broilers.

Fermentation represents an attractive alternative method for feather meal (FM) efficient bioconversion and its nutritional value enhancement. This study investigated the effects of FM processing methods on broilers. Experimental diets were 1) a control diet (without FM), 2) a diet containing 4% raw FM (RFM), 3) a diet containing 4% processed FM (PFM) by autoclave (Au-PFM), 4) a diet containing 4% fermented FM (FFM) by Bacillus licheniformis (Bl-FFM), 5) a diet containing 4% FFM by Bacillus subtilis (Bs-FFM), 6) a diet containing 4% FFM by Aspergillus niger (An-FFM), 7) a diet containing 4% FFM by B. licheniformis + B. subtilis + A. niger (Co-FFM), and 8) a diet containing 4% PFM by an enzyme (En-PFM). Results showed that FFMs increased the contents of ash, ether extract, total volatile nitrogen, and amino acids including Lys, Met, Thr, Trp, His, Leu, Gly, Ile, Phe, and Tyr, while decreased crude fiber, crude protein, and dry matter content. The production parameters of birds fed Co-FFM were similar to the control group. In addition, FFMs decreased serum total cholesterol (1.46-fold), triglyceride (1.61-fold), very low-density lipoprotein cholesterol (1.61-fold), and low-density lipoprotein cholesterol (2.27-fold). Furthermore, Co-FFM improved intestinal morphology, enzyme activities, and beneficial bacterial populations. In conclusion, Co-FFM, improves the nutritional value of FM, converting it into a decent source of dietary protein for broilers.

Volatile organic compounds in preen oil and feathers - a review.

For a long time birds were assumed to be anosmic or at best microsmatic, with olfaction a poorly understood and seldom investigated part of avian physiology. The full viability of avian olfaction was first discovered through its functions in navigation and foraging. Subsequently, researchers have investigated the role of olfaction in different social and non-social contexts, including reproduction, kin recognition, predator avoidance, navigation and foraging. In parallel to the recognition of the importance of olfaction for avian social behaviour, there have been advances in the techniques and methods available for the sampling and analysis of trace volatiles and odourants, leading to insights into the chemistry underlying chemical communication in birds. This review provides (i) an overview of the current state of knowledge regarding the volatile chemical composition of preen oil and feathers, its phylogenetic coverage, chemical signatures and their potential functions, and (ii) a discussion of current methods used for the isolation and detection of volatiles. Finally, lines for future research are proposed.