Genetic Mapping and Biochemical Basis of Yellow Feather Pigmentation in Budgerigars.

Parrot feathers contain red, orange, and yellow polyene pigments called psittacofulvins. Budgerigars are parrots that have been extensively bred for plumage traits during the last century, but the underlying genes are unknown. Here we use genome-wide association mapping and gene-expression analysis to map the Mendelian blue locus, which abolishes yellow pigmentation in the budgerigar. We find that the blue trait maps to a single amino acid substitution (R644W) in an uncharacterized polyketide synthase (MuPKS). When we expressed MuPKS heterologously in yeast, yellow pigments accumulated. Mass spectrometry confirmed that these yellow pigments match those found in feathers. The R644W substitution abolished MuPKS activity. Furthermore, gene-expression data from feathers of different bird species suggest that parrots acquired their colors through regulatory changes that drive high expression of MuPKS in feather epithelia. Our data also help formulate biochemical models that may explain natural color variation in parrots. VIDEO ABSTRACT.

Genetic Basis and Evolution of Structural Color Polymorphism in an Australian Songbird.

Island organisms often evolve phenotypes divergent from their mainland counterparts, providing a useful system for studying adaptation under differential selection. In the white-winged fairywren (Malurus leucopterus), subspecies on two islands have a black nuptial plumage whereas the subspecies on the Australian mainland has a blue nuptial plumage. The black subspecies have a feather nanostructure that could in principle produce a blue structural color, suggesting a blue ancestor. An earlier study proposed independent evolution of melanism on the islands based on the history of subspecies divergence. However, the genetic basis of melanism and the origin of color differentiation in this group are still unknown. Here, we used whole-genome resequencing to investigate the genetic basis of melanism by comparing the blue and black M. leucopterus subspecies to identify highly divergent genomic regions. We identified a well-known pigmentation gene ASIP and four candidate genes that may contribute to feather nanostructure development. Contrary to the prediction of convergent evolution of island melanism, we detected signatures of a selective sweep in genomic regions containing ASIP and SCUBE2 not in the black subspecies but in the blue subspecies, which possesses many derived SNPs in these regions, suggesting that the mainland subspecies has re-evolved a blue plumage from a black ancestor. This proposed re-evolution was likely driven by a preexisting female preference. Our findings provide new insight into the evolution of plumage coloration in island versus continental populations, and, importantly, we identify candidate genes that likely play roles in the development and evolution of feather structural coloration.

Feather corticosterone is lower in translocated and historical populations of the endangered Laysan duck (Anas laysanensis).

Identifying reliable bioindicators of population status is a central goal of conservation physiology. Physiological stress measures are often used as metrics of individual health and can assist in managing endangered species if linked to fitness traits. We analysed feather corticosterone, a cumulative physiological stress metric, of individuals from historical, translocated, and source populations of an endangered endemic Hawaiian bird, the Laysan duck (Anas laysanensis). We hypothesized that feather corticosterone would reflect the improved reproduction and survival rates observed in populations translocated to Midway and Kure Atolls from Laysan Island. We also predicted less physiological stress in historical Laysan birds collected before ecological conditions deteriorated and the population bottleneck. All hypotheses were supported: we found lower feather corticosterone in the translocated populations and historical samples than in those from recent Laysan samples. This suggests that current Laysan birds are experiencing greater physiological stress than historical Laysan and recently translocated birds. Our initial analysis suggests that feather corticosterone may be an indicator of population status and could be used as a non-invasive physiological monitoring tool for this species with further validation. Furthermore, these preliminary results, combined with published demographic data, suggest that current Laysan conditions may not be optimal for this species.

Isolation, identification, and molecular characterization of potential keratinolytic fungus sp. from Southern Assam: relevance to poultry wastes and its biological management.

Feather waste is a highly prevalent form of keratinous waste that is generated by the poultry industry. The global daily production of feather waste has been shown to approach 5 million tons, typically being disposed of through methods such as dumping, landfilling, or incineration which contribute significantly to environmental pollutions. The proper management of these keratinous wastes is crucial to avoid environmental contamination. The study was carried out to isolate the keratinolytic fungi from the poultry disposal sites of different region of North-East India to evaluate its potential in bioremediation of the feathers wastes. Out of 12 fungal strains isolated from the sites, the fungus showing the highest zone of hydrolysis on both the skim milk and keratin agar medium was selected for the study and the molecular identification of the isolate was performed through DNA sequence analysis by amplifying the internal transcribed spacer (ITS) region. The sequence results showed higher similarity (above 95%) with Aspergillus spp. and was named Aspergillus sp. Iro-1. The strain was further analyzed for its feather degrading potential which was performed in submerged conditions under optimized conditions. The study showed that the strain could effectively degrade the feathers validated through weight loss method, and the structural deformations in the feathers were visualized through scanning electron microscopy (SEM). Aspergillus sp. Iro-1 was obtained from the southern region of Assam. It would be of great importance as the implementation of this sp. can help in the bioremediation of feathers wastes in this region. This is the first study of identification of feather degrading fungus from southern part of Assam (Barak).

Host space, not energy or symbiont size, constrains feather mite abundance across passerine bird species.

Comprehending symbiont abundance among host species is a major ecological endeavour, and the metabolic theory of ecology has been proposed to understand what constrains symbiont populations. We parameterized metabolic theory equations to investigate how bird species' body size and the body size of their feather mites relate to mite abundance according to four potential energy (uropygial gland size) and space constraints (wing area, total length of barbs and number of feather barbs). Predictions were compared with the empirical scaling of feather mite abundance across 106 passerine bird species (26,604 individual birds sampled), using phylogenetic modelling and quantile regression. Feather mite abundance was strongly constrained by host space (number of feather barbs) but not by energy. Moreover, feather mite species' body size was unrelated to the body size of their host species. We discuss the implications of our results for our understanding of the bird-feather mite system and for symbiont abundance in general.

Empirically tuned theory reveals why symbiont abundance 'mite' vary across hosts.

Research Highlight: del Mar Labrador, M., Serrano, D., Doña, J., Aguilera, E., Arroyo, J. L., Atiénzar, F., Barba, E., Bermejo, A., Blanco, G., Borràs, A., Calleja, J. A., Cantó, J. L., Cortés, V., de la Puente, J., de Palacio, D., Fernández-González, S., Figuerola, J., Frías, Ó., Fuertes-Marcos, B. Garamszegi, L. Z., Gordo, Ó., Gurpegui, M., Kovács, I., Martínez, J. L., Meléndez, L., Mestre, A., Møller, A. P., Monrós, J. S., Moreno-Opo, R., Navarro, C., Pap, P. L., Pérez-Tris, J., Piculo, R., Ponce, C., Proctor, H., Rodríguez, R., Sallent, Á., Senar, J., Tella, J. L., Vágási, C. I., Vögeli, M., & Jovani, R. (2023). Host space, not energy or symbiont size, constrains feather mite abundance across passerine bird species. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.14032. Symbionts represent crucial links between species in ecosystems. Consequently, understanding their patterns of abundance is a major goal in the study of symbioses. However, multiple biotic and abiotic factors may regulate symbionts, and disentangling the mechanisms that drive variation in their abundance across host species is challenging. One promising strategy to approach this challenge is to incorporate biologically relevant data into theoretical models. In a recent study, Labrador et al. (2023) used this strategy to investigate the poorly understood symbiosis between feather mites and their avian hosts. They integrate a remarkable amount of empirical data with models based on the metabolic theory of ecology to determine what factors limit feather mite abundance across European passerines. Their quantitative analyses indicate that the number of feather barbs limits mite abundance across host species, suggesting that mite populations are spatially, but not energetically, constrained. These findings not only reveal mechanisms that may drive the variation in feather mite abundances across hosts, but also advance our understanding of the ecology of interspecific interactions more generally.

Optimizing protocols for monitoring in vivo replication of a novel chimeric Marek's disease vaccine with an insertion of the long terminal repeat of reticuloendotheliosis virus in the CVI988 strain genome (CVI-LTR).

Monitoring Marek's disease (MD) vaccination is routinely done by evaluating the load of MD vaccine in the feather pulp (FP) between 7 and 10 days of age. However, attempts in our laboratory to detect a novel CVI-LTR vaccine in the FP samples from commercial flocks failed. The objective of this study was to evaluate the most suitable tissue and age to monitor CVI-LTR vaccination. We used two different commercial CVI988 vaccines as controls. One hundred and sixty 1-day-old commercial brown layers were vaccinated with either CVI-LTR, CVI988-A, CVI988-B or remained unvaccinated. Samples of the spleen, thymus, and bursa were collected at 3, 4, 5, and 6 days of age and samples of FP were collected at 7 and 21 days for DNA isolation. Our results showed that CVI-LTR replicated earlier than CVI988 vaccines in the lymphoid organs but was not detected in the FP at either 7 or at 21 days of age. We also confirmed that either the spleen or thymus collected at 4-6 days was a suitable sample to monitor CVI-LTR vaccination in commercial flocks. Finally, we evaluated the load of oncogenic MDV DNA in five commercial flocks that were vaccinated with either CVI-LTR + rHVT or CVI988-A + rHVT. The load of oncogenic MDV DNA was evaluated at 21 days in the FP in 20 chickens per group. Our results demonstrated that CVI-LTR was more successful in reducing oncogenic MDV DNA at 21 days of age than the CVI988-A strain.RESEARCH HIGHLIGHTSCVI-LTR replicates in the thymus and spleen earlier than CVI988.CVI-LTR replicates in lymphoid organs but it cannot be detected in feather pulp.CVI-LTR reduced the load of oncogenic MDV DNA more efficiently than CVI988.

A preliminary study on short- and medium-chain chlorinated paraffins in duck farms: Concentrations, distribution, and dietary exposure risks.

Chlorinated paraffins (CPs) in poultry feed and the farm environment might bioaccumulate in poultry eggs. Unlike chickens, which are mostly raised in cages, ducks are commonly raised free range. This would expose ducks to CPs in the environment. However, information on the presence of CPs on duck farms is scarce. In the present study, samples of duck eggs, duck feathers, poultry feed, and soil were collected from 25 duck farms in South China. Forty-eight congener groups of short- and medium-chain CPs (SCCPs and MCCPs) were detected in the samples. Interestingly, relatively high concentrations of SCCPs and MCCPs were found in the duck feathers. The median concentrations of SCCPs and MCCPs in the duck eggs, feathers, feed and soil were: 46 and 18 ng/g wet weight, 2460 and 992 ng/g, 103 and 47 ng/g, and 24 and 10 ng/g dry weight, respectively. The dominant groups of SCCPs and MCCPs were C10Cl6-7 and C14Cl7-8, respectively. The close relationship between duck feathers and poultry feed indicated that the duck feathers might act as a bioindicator for the exposure of ducks to CPs. The margin of exposure approach was used to assess the health risk, with the results showing that the consumption of duck eggs posed a low risk to different age groups from exposure to SCCPs and MCCPs.

A scientific version of understanding "Why did the chickens cross the road"? - A guided journey through Bacillus spp. towards sustainable agriculture, circular economy and biofortification.

The world, a famished planet with an overgrowing population, requires enormous food crops. This scenario compelled the farmers to use a high quantity of synthetic fertilizers for high food crop productivity. However, prolonged usage of chemical fertilizers results in severe adverse effects on soil and water quality. On the other hand, the growing population significantly consumes large quantities of poultry meats. Eventually, this produces a mammoth amount of poultry waste, chicken feathers. Owing to the protein value of the chicken feathers, these wastes are converted into protein hydrolysate and further extend their application as biostimulants for sustained agriculture. The protein profile of chicken feather protein hydrolysate (CFPH) produced through Bacillus spp. was the maximum compared to physical and chemical protein extraction methods. Several studies proved that the application of CFPH and active Bacillus spp. culture to soil and plants results in enhanced plant growth, phytochemical constituents, crop yield, soil nutrients, fertility, microbiome and resistance against diverse abiotic and biotic stresses. Overall, "CFPH - Jack of all trades" and "Bacillus spp. - an active camouflage to the surroundings where they applied showed profound and significant benefits to the plant growth under the most adverse conditions. In addition, Bacillus spp. coheres the biofortification process in plants through the breakdown of metals into metal ions that eventually increase the nutrient value of the food crops. However, detailed information on them is missing. This can be overcome by further real-world studies on rhizoengineering through a multi-omics approach and their interaction with plants. This review has explored the best possible and efficient strategy for managing chicken feather wastes into protein-rich CFPH through Bacillus spp. bioconversion and utilizing the CFPH and Bacillus spp. as biostimulants, biofertilizers, biopesticides and biofortificants. This paper is an excellent report on organic waste management, circular economy and sustainable agriculture research frontier.

Dark Morph of the Oriental Honey-Buzzard (Pernis ptilorhynchus orientalis) is Attributable to Specific MC1R Haplotypes.

A thorough understanding of the development of complex plumages in birds necessitates the acquisition of genetic data pertaining to the mechanism underlying this phenomenon from various avian species. The oriental honey-buzzard (Pernis ptilorhynchus orientalis), a tropical summer migrant to Northeast Asia, including Japan, exemplifies this aspect owing to the diversity of its ventral coloration and intra-feather barring patterns. However, genetic polymorphism responsible for this diversity has not been identified yet. This study aimed to investigate the link between dark-plumed phenotypes of this subspecies and haplotypes of the melanocortin-1-receptor (MC1R) gene. A draft sequence of MC1R was constructed using next generation sequencing and subsequently amplified using designed polymerase chain reaction (PCR) primers. The genome sequences of 32 honey-buzzard individuals were determined using PCR, and 12 MC1R haplotype sequences were obtained. Among these haplotypes, we found that unique haplotypes with nine non-synonymous substitutions and four or five synonymous substitutions in the coding region had a perfect correlation with the dark-plumed phenotype. The lack of correlation between the genotype of ASIP coding region and plumage phenotype reiterated that the dark morph is attributable to specific MC1R haplotypes. The absence of a correlation between genetic polymorphisms of MC1R and the intra-feather barring patterns, as well as the diversity observed within lighter ground color classes (pale and intermediate), implies the involvement of alternative molecular mechanisms in the manifestation of the aforementioned phenotypes.

Differential expression of ASIP transcripts reveals genetic mechanism underpinning black-tail independence from body plumage in yellow-bodied chickens.

The genetic foundation of chicken body plumage color has been extensively studied. However, little attention has been paid to the inheritance patterns and molecular mechanisms underlying the formation of distal feather colors (tail and wingtip). Differences in these colors are common; for example, the Chinese Huiyang Beard chicken has black tail feathers, but yellow body plumage. Here, the hybrid offspring of Huiyang Beard and White Leghorn chickens were used to study the inheritance patterns of tail-feather color. The expression levels of pigment genes in differently colored feather follicles were analyzed using quantitative real-time PCR. The results showed that genetic regulation of tail-feather color was independent of body-plumage color. The Dominant White locus inhibited eumelanin synthesis in tail feathers without affecting the formation of yellow body plumage, whereas the Silver locus had the opposite effect. The expression of agouti signaling protein (ASIP) gene class 1 transcripts was significantly lower in black tail-feather follicles than in yellow body follicles, whereas tyrosinase-related protein 1 (TYRP1) gene expression was significantly higher in black tail feathers. These differentially expressed genes were confirmed to exert an effect on eumelanin and pheomelanin formation in feathers, thus influencing the regulation of chicken tail-feather color. In conclusion, this study lays the foundation for further research on the genetic mechanisms of regional differences in feather color, contributing to a better understanding of plumage pigmentation in chickens.

Transcriptome Sequencing and Mass Spectrometry Reveal Genes Involved in the Non-mendelian Inheritance-Mediated Feather Growth Rate in Chicken.

The feather growth rate in chickens included early and late feathering. We attempted to characterize the genes and pathways associated with the feather growth rate in chickens that are not in agreement with Mendelian inheritance. Gene expression profiles in the hair follicle tissues of late-feathering cocks (LC), early-feathering cocks (EC), late-feathering hens (LH), and early-feathering hens (EH) were acquired using RNA sequencing (RNA-seq), mass spectrometry (MS), and quantitative reverse transcription PCR (qRT­PCR). A total of 188 differentially expressed genes (DEGs) were ascertained in EC vs. LC and 538 DEGs were identified in EH vs. LH. We observed that 14 up-regulated genes and 9 down-regulated genes were screened both in EC vs. LC and EH vs. LH. MS revealed that 41 and 138 differentially expressed proteins (DEPs) were screened out in EC vs. LC and EH vs. LH, respectively. Moreover, these DEGs and DEPs were enriched in multiple feather-related pathways, including JAK-STAT, MAPK, WNT, TGF-ß, and calcium signaling pathways. qRT-PCR assay showed that the expression of WNT8A was decreased in LC compared with EC, while ALK and GRM4 expression were significantly up-regulated in EH relative to LH. This study helps to elucidate the potential mechanism of the feather growth rate in chickens that do not conform to genetic law.

Per- and polyfluoroalkyl substances in waterbird feathers around Poyang Lake, China: Compound and species-specific bioaccumulation.

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.

Bacillus velezensis strain NA16 shows high poultry feather-degrading efficiency, protease and amino acid production.

Isolated Bacillus velezensis strain NA16, which produces proteases, amino acids and the transcription levels of different keratinolytic enzymes and disulfide reductase genes in whole gene sequencing, was evaluated during feather degradation. The result shows under optimum fermentation conditions, chicken feather fermentation showed total amino acid concentration of 7599 mg/L, degradation efficiency of 99.3% at 72 h, and protease activity of 1058 U/mL and keratinase activity of 288 U/mL at 48 h. Goose feather fermentation showed total amino acid concentration of 4918 mg/L (96 h), and degradation efficiency was 98.9% at 120 h. Chicken feather fermentation broth at 72 h showed high levels of 17 amino acids, particularly phenylalanine (1050 ± 1.90 mg/L), valine (960 ± 1.04 mg/L), and glutamic (950 ± 3.00 mg/L). Scanning electron microscopy and Fourier transform infrared analysis revealed the essential role of peptide bond cleavage in structural changes and degradation of feathers. Protein purification and zymographic analyses revealed a key role in feather degradation of the 39-kDa protein encoded by gene1031, identified as an S8 family serine peptidase. Whole genome sequencing of NA16 revealed 26 metalloproteinase genes and 22 serine protease genes. Among the proteins, S8 family serine peptidase (gene1031, gene1428) and S9 family peptidase (gene3132) were shown by transcription analysis to play major roles in chicken feather degradation. These findings revealed the transcription levels of different families of keratinolytic enzymes in the degradation of feather keratin by microorganisms, and suggested potential applications of NA16 in feather waste management and amino acid production.

Sequestration of an Azo Dye by a Potential Biosorbent: Characterization of Biosorbent, Adsorption Isotherm and Adsorption Kinetic Studies.

This study explores the detailed characterization of a biosorbent (Hen Feather) and its efficient use in eradicating the azo dye Metanil Yellow (MY) from its aqueous solutions. Effects of a range of experimental parameters, including pH, initial dye concentration, biosorbent dosage and contact time on the adsorption, were studied. A detailed physical and chemical characterization of the biosorbent was made using SEM, XRD, XPS and FTIR. During the optimization of adsorption parameters, the highest dye uptake of almost 99% was recorded at pH 2, dye concentration 2 × 10-5 M, 0.05 g of biosorbent and a contact period of 75 min. Various adsorption isotherm models were studied to gather different adsorption and thermodynamic parameters. The linearity of the Langmuir, Freundlich and D-R adsorption isotherms indicate homogeneous, multilayer chemisorption with high adsorption affinity between the dye and biosorbent. Values of the changes in the Gibbs free energy (ΔG°) and the enthalpy (ΔH°) of the adsorption process have been calculated, these values indicate that it is a spontaneous and endothermic process. Kinetics of the adsorption were also measured, and it was established that the adsorption of MY over Hen Feather follows a pseudo-second-order kinetic model at temperatures 30, 40 and 50 °C. The findings of this investigation clearly indicate that the studied biosorbent exhibits a high affinity towards the dye (MY), and it can be effectively, economically and efficiently used to sequestrate and eradicate MY from its aqueous solutions.

Factors associated with keel bone damage - a longitudinal study of commercial layer flocks during the laying period.

1. Keel bone damage, such as deformations and fractures, is a severe problem regarding animal welfare in layers. To identify risk factors under commercial conditions, 33 layer flocks (22 barn, 11 free range) with white (n = 18), brown (n = 11) and mixed (n = 4) genotypes were examined.2. Keel bone status was frequently scored by palpation throughout the laying period. Data on housing and management conditions were collected. Multiple regression and Generalized Estimating Equations procedure were used for analysis.3. At 65-74 weeks of age, the prevalence of keel bone damage ranged between 26% and 74%. White genotypes and those kept in multi-tier systems developed significantly (p < 0.05) more keel bone damage than brown genotypes or those kept in single-tier systems. Wing feather condition was associated with keel bone damage (p < 0.05), while other investigated variables regarding health, housing and management were not associated.4. In conclusion, housing and management should be adapted to meet the birds' specific needs in multi-tier systems, which may vary for brown and white genotypes. Whether those differences result from genotype associated predispositions or other individual traits remains to be determined.

Examining the relationship between different naturally-occurring maxillary beak shapes and their ability to cause damage in commercial laying hens.

1. Using chicken models to avoid unnecessary harm, this study examined the relationship between naturally-occurring maxillary (top) beak shapes and their ability to cause pecking damage.2. A selection of 24 Lohmann Brown laying hens from a total population of 100 were sorted into two groups based on their maxillary beak shape, where 12 were classified as having sharp beaks (SB) and 12 as having blunt beaks (BB).3. All hens were recorded six times in a test pen which contained a chicken model (foam block covered with feathered chicken skin) and a video camera. During each test session, the number of feathers removed from the model, the change in skin and block weight (proxies for tissue damage) and the percentage of successful pecks (resulting in feather and/or tissue removal) were recorded.4. SB hens removed more feathers from the model and had a greater change in skin weight than BB hens. The mean number of pecks made at the model did not differ between the beak shape groups; however, SB hens had a greater percentage of successful pecks, resulting in feather and/or tissue removal, compared to BB hens.5. In conclusion, SB hens were more capable of removing feathers and causing damage. Birds performed more successful pecks resulting in feather and/or tissue removal as they gained experience pecking at the model.

Characterization of circRNA expression profiles associated with non-Mendelian inheritance in feather growth of chickens.

1. Non-coding RNAs, such as miRNAs, play a crucial role in chicken feather growth rate. However, circular RNA (circRNA) expression profiles in fast- and slow-feathering chickens that follow and do not follow Mendelian inheritance are unclear.2. The circRNA expression profiles was analysed by RNA sequencing of hair follicles of slow-feathering chickens that follow genetic rules and fast-feathering chickens that did not follow genetic rules. Differentially expressed circRNA-miRNA-mRNA competing endogenous RNA (ceRNA) network was then constructed and the key factors and regulation mechanisms controlling feather growth rate were identified.3. The results revealed that 67 circRNAs were significantly differentially expressed in hens, including 22 up-regulated and 45 down-regulated circRNAs in non-Mendelian inheritance-mediated fast-feathering hens compared with Mendelian inheritance-mediated slow-feathering hens. In addition, 16 significantly differentially expressed circRNAs were identified in cockerels, including nine up-regulated and seven down-regulated circRNAs in non-Mendelian inheritance-mediated fast- compared with Mendelian inheritance-mediated slow-feathering cocks. Moreover, circRNA-mediated ceRNA regulation of hair follicle formation was particularly abundant in the Jak-STAT, Wnt and Toll-like receptor signalling pathways. Furthermore, circABI3BP was seen to be a crucial circRNA in regulating feather growth rate, by binding with gga-miR-1649-5p to regulate SSTR2 expression.4. In conclusion, this study analysed circRNA expression profiles in fast- and slow-feathering chickens that follow and do not follow Mendelian inheritance, which laid the foundation for understanding the role of circRNA in chicken feather growth rate.

Cottonseed meal protein hydrolysate influences growth performance, carcass characteristics, serum biochemical indices, and intestinal morphology in yellow-feather broilers.

This study investigated the effects of cottonseed meal protein hydrolysate (CPH) on the growth performance, carcass characteristics, serum biochemical indices, intestinal morphology, and enzyme activities of yellow-feather broilers. We randomly divided 240 chicks into four groups, each with six replicates: a basal diet with 0% (CON), 1% (LCPH), 3% (MCPH), or 5% (HCPH) CPH. The trail spanned 63 days and included three phases: Days 1-21, 22-42, and 43-63. Increased average daily gain (ADG) and decreased ratio of feed to gain (F/G) with LCPH were observed in 21-day-old broilers (P < 0.05). MCPH led to higher ADG and average daily feed intake (ADFI) in 42-day-old broilers (P < 0.05). Additionally, CPH supplementation resulted in increased dressing percentage, percentage of half-eviscerated yield, percentage of eviscerated yield, breast muscle rate, and leg muscle rate were observed (P < 0.05) with diet. The serum levels of total protein (TP), high-density lipoprotein cholesterol (HDL-C), calcium (Ca), and phosphorus (P) were enhanced, and blood urea nitrogen (BUN) and triglyceride (TG) levels decreased with diet and CPH (P < 0.05). CPH increased the length of the jejunum and ileum and the weight of the duodenum, jejunum, and ileum in 21-day-old broilers (P < 0.05). Alterations in the duodenal villus structure in broilers occurred on Days 21 and 42, and the CPH groups performed better; however, a similar change occurred in the jejunum on Days 42 and 63 (P < 0.05). MCPH and HCPH enhanced trypsin activity in the duodenum of 21-day-old and 63-day-old broilers (p < 0.05). Chymotrypsin activity increased (P > 0.05) in the duodenum of 63-day-old broilers fed MCPH. Lipase activity increased (P < 0.05) in the jejuna of 21-day-old broilers treated with HCPH. CPH increased trypsin activity in the ilea of 21-day-old broilers (P < 0.05). These results showed that CPH influenced the growth performance, carcass characteristics, serum biochemical indices, and intestinal morphology of yellow-feather broilers, which are related to growth stage. The recommended CPH level in broilers is 1% before 21 days of age and 3% after 21 days of age.

Effects of mulberry leaf powder water extract supplementation on the growth performance, immunity, antioxidant, meat quality and intestinal microbiota of yellow feather broilers.

A 50-day feeding trial was conducted to evaluate the effects of mulberry leaf powder water extract (MLE) on the growth performance, immunity, antioxidant, meat quality and intestinal microbiota of yellow feather broilers. A total of 720 birds (initial body weight 40.07 ± 0.05 g) were randomly distributed into four groups with six replicates per group and 30 birds per replicate. Four diets were formulated with 0% (CON), 200 mg/kg MLE (MLE200), 400 mg/kg MLE (MLE400) and 600 mg/kg MLE (MLE600) supplementation. Results showed that the addition of 200-600 mg/kg MLE to the diet significantly increased the body weight (BW) and average daily weight gain (ADG), but feed to gain ratio (F/G) were linearly decreased (p = 0.045) as dietary MLE increased. Birds fed MLE400 had higher (p < 0.05) total antioxidant capacity (T-AOC), interleukin-10 (Il-10), secretory immunoglobulin A (SIgA) and complement 3 (C3) contents than those fed CON, whereas MLE400 had lower malondialdehyde (MDA) content than CON (p < 0.05). Analysis of 16 S rDNA indicated that supplementation with 200 mg/kg MLE increased the Shannon indices in the caecum (p < 0.05). Supplementation with MLE decreased the abundance of the phylum Proteobacteria and genus Helicobacter, and increased the abundance of the phylum Bacteroidetes in the caecum in broiler chickens (p < 0.05). The drip loss rate in the MLE600 was significantly diminished (p < 0.05), whereas the shear force was significantly elevated (p < 0.05). In summary, dietary supplementation with MLE can effectively improve growth performance, intestinal immunity, serum antioxidant capacity, meat quality and intestinal microbiota of yellow feather broilers. The most appropriate MLE supplementation level was 400 mg/kg. This study provides a practical strategy for the dietary application of MLE in yellow feather broilers.