Automated BigSMILES conversion workflow and dataset for homopolymeric macromolecules.

The simplified molecular-input line-entry system (SMILES) has been utilized in a variety of artificial intelligence analyses owing to its capability of representing chemical structures using line notation. However, its ease of representation is limited, which has led to the proposal of BigSMILES as an alternative method suitable for the representation of macromolecules. Nevertheless, research on BigSMILES remains limited due to its preprocessing requirements. Thus, this study proposes a conversion workflow of BigSMILES, focusing on its automated generation from SMILES representations of homopolymers. BigSMILES representations for 4,927,181 records are provided, thereby enabling its immediate use for various research and development applications. Our study presents detailed descriptions on a validation process to ensure the accuracy, interchangeability, and robustness of the conversion. Additionally, a systematic overview of utilized codes and functions that emphasizes their relevance in the context of BigSMILES generation are produced. This advancement is anticipated to significantly aid researchers and facilitate further studies in BigSMILES representation, including potential applications in deep learning and further extension to complex structures such as copolymers.

Comparing Subjective Similarity of Automated Driving Styles to Objective Distance-Based Similarity.

OBJECTIVE: This study explores subjective and objective driving style similarity to identify how similarity can be used to develop driver-compatible vehicle automation. BACKGROUND: Similarity in the ways that interaction partners perform tasks can be measured subjectively, through questionnaires, or objectively by characterizing each agent's actions. Although subjective measures have advantages in prediction, objective measures are more useful when operationalizing interventions based on these measures. Showing how objective and subjective similarity are related is therefore prudent for aligning future machine performance with human preferences. METHODS: A driving simulator study was conducted with stop-and-go scenarios. Participants experienced conservative, moderate, and aggressive automated driving styles and rated the similarity between their own driving style and that of the automation. Objective similarity between the manual and automated driving speed profiles was calculated using three distance measures: dynamic time warping, Euclidean distance, and time alignment measure. Linear mixed effects models were used to examine how different components of the stopping profile and the three objective similarity measures predicted subjective similarity. RESULTS: Objective similarity using Euclidean distance best predicted subjective similarity. However, this was only observed for participants' approach to the intersection and not their departure. CONCLUSION: Developing driving styles that drivers perceive to be similar to their own is an important step toward driver-compatible automation. In determining what constitutes similarity, it is important to (a) use measures that reflect the driver's perception of similarity, and (b) understand what elements of the driving style govern subjective similarity.

Research Note: Muscle hypertrophy is associated with reversed sexual dimorphism in body size of quail.

Sexual dimorphism is phenotypic differences between males and females in the same species. In general, males in most animals are larger than females at the same age, however, in quail, females have a larger body size with greater muscle mass than males. To understand what characteristics in muscle growth play roles in reversed sexual dimorphism in quail, the weights and the characteristics of the pectoralis major and gastrocnemius muscles (PM and GM, respectively) of male and female quail were compared in the current study. The data showed that 15-wk-old female quail have significantly heavier bodies, and PM and GM weights compared to male quail (1.27-folds, 1.29-folds, and 1.16-folds, respectively). To compare muscle characteristics such as hypertrophy (increased size) and hyperplasia (increased cell number), the PM and GM were stained using hematoxylin and eosin, and then histological characteristics such as total cross-sectional area (CSA), number and size of myofibers, and muscle bundle of the muscles were measured and analyzed. In both PM and GM, there were no differences in total numbers of myofibers and muscle bundles as well as the average numbers of myofibers per bundle between sexes. However, the sizes of myofiber and the bundle were significantly increased in female compared to male (1.33-folds and 1.28-folds in PM, and both 1.23-folds in GM, respectively). The findings of the current study suggest that muscle hypertrophy in female quail, not hyperplasia, can be attributed to the sexual dimorphism in quail size.

Greater numbers and sizes of muscle bundles in the breast and leg muscles of broilers compared to layer chickens.

Meat-type (broiler) and egg-type (layer) chickens were bred by intensive selection over the years, resulting in more numbers and larger sizes of myofibers. Although the characteristics are important parameters in muscle growth and meat quality, muscle bundle characteristics have not been studied in poultry. Therefore, this study aimed to compare the histological characteristics of myofibers and muscle bundles in muscles between male broiler (Ross broiler breed) chickens and layer (Hy-Line) chickens. Chicken muscles, pectoralis major (PM) and gastrocnemius (GM), were sampled at the age of 49 days and stained to analyze histological characteristics. Expectedly, body weights (BWs) and weights of PM and GM muscles in 49-day-old broilers were significantly heavier than those in layers. Within PM, broilers exhibited greater number and cross-sectional area (CSA) of myofibers than layers (3.3- and 3.3-fold, respectively). The total number and CSA of PM muscle bundles were approximately 1.5 and 6.6 times greater, respectively, in broilers than layers. Moreover, broilers exhibited 2 times greater number of myofibers per bundle of PM muscle than layers. Within GM, myofiber number and CSA were 2.3- and 2.4-fold greater, respectively, in broilers than layers. In addition, the total number of muscle bundles and bundle CSA were 2.5- and 2.1-fold greater, respectively, in broilers than in the layers. The novel findings of the current study provide evidence that greater muscle mass of broilers occurs by both hyperplasia and hypertrophy of muscle bundles and myofibers.

Research Note: Injection of adenoviral CRISPR/Cas9 system targeting melanophilin gene into different sites of embryos induced regional feather color changes in posthatch quail.

Poultry species is an important animal model in both avian research and the poultry industry. To advance our understanding of genetic factors and benefit both fields, a gene of interest can be genetically edited, and consequential phenotypic changes can be investigated. Injection of adenovirus containing the CRISPR/Cas9 system into avian blastoderm induced genome editing in blastodermal cells randomly, including primordial germ cells, which results in generation of whole-body knockout in the offspring of the virus-injected quail. However, to observe phenotypic and functional changes in whole-body, homozygous knockout of genes using this genome editing technology requires at least 2 generations of breeding of chimeric, and heterozygotes birds. In the current study, we developed a strategy to investigate the gene function in 1-generation by inducing regional genome editing around the injection sites with CRISPR/Cas9 adenovirus. The adenoviral CRISPR/Cas9 vector targeting the melanophilin (Mlph) gene, regulating feather pigmentation, was injected into 2 different regions of embryos, the cervical flexure of quail embryos at HH stage 13 to 15 and the tip of the upper limb bud of embryos at HH stage 22 to 24, to induce genome editing in those regions. Indel mutations in the target loci of the Mlph gene were detected by extracting genomic DNA from the embryonic tissues, and consequential phenotypes, feather color changes, were analyzed at 1 mo after hatch. Injection of the adenovirus into the cervical flexure and the tip of the upper limb bud of embryos resulted in 8 to 21% efficiency of indel mutation in the embryonic cells of the injected regions. In the posthatch quail, gray feathers were shown on their upper back and primary wing feathers, corresponding to the injection sites at embryos. Successful validation of this strategy for inducing genome editing in parts of tissues within 1-generation will accelerate studies on genetic functions with advantages of less time and cost, facilitating avian research and providing foundations for future application for the poultry industry.

Research Note: Distribution of nanospheres in the cuticle layer of the eggshell in major poultry species.

Mineralized eggshell is a unique and protective structure in an avian egg. Among different eggshell layers, the cuticle layer is an outermost layer and plays a critical role in protection against bacterial infection. Although the importance of nanosphere in the cuticle layer on the antimicrobial function has been widely accepted, the detailed nanostructure of the cuticle layer in the major poultry species has not been investigated. In the current study, eggs from Japanese quail, commercial layer chickens, mixed breed turkeys, and White Pekin ducks were collected. To investigate the nanostructure throughout the cuticle layer, images of the cross-sectional cuticle layer were taken using a scanning electron microscope (SEM). Unlike the cuticle layer in ducks showing deformed bunched nanospheres, clearly separated nanospheres were present throughout the cuticle layer in quail, chickens, and turkeys. The average size of the nanosphere was the biggest in turkeys and similar between quail and chickens. Most importantly, the size of nanospheres was increased as they ascended from the bottom of the cuticle layer in quail, showing a positive correlation between the size and distance of the nanospheres. However, different sizes of nanospheres were randomly distributed throughout the cuticle layer in chickens and turkeys, showing a weak correlation in chickens and no correlation in turkeys between the size and distance of nanospheres. These new findings in different nanostructures of the cuticle layers in quail, chickens, turkeys, and ducks will serve as a new foundation to better relate their structures with functions.

The effects of myostatin mutation on the tibia bone quality in female Japanese quail before and after sexual maturation.

In the modern layer industry, improvement of bone quality is one of the prior tasks to solve from economic and welfare standpoints. In addition to nutritional and environmental factors, genetic factors have been considered major factors regulating bone quality in layers but are yet to be fully investigated due to limitations on available animal models. Initially, the myostatin (MSTN) gene was genetically edited in quail to investigate the effect of MSTN mutation on economic traits in meat producing poultry species. In the current study, the function of the MSTN gene on regulation of bone quality in layers was investigated using MSTN mutant female quail as an animal model. Tibia bones were collected from wild-type (WT) and MSTN mutant female quail at 5 wk old and 4 mo old, representing prelaying and actively laying stages, respectively. Left tibia bones were analyzed by microcomputed tomography scanning to evaluate the architectural characteristics, while bone breaking strength (BBS) was measured using right tibia bones. At 5 wk of age, MSTN mutant female quail showed higher BBS and values on parameters related to bone quality such as bone mineral contents (BMC), bone mineral density (BMD), bone volume (BV), and/or trabecular bone thickness in whole diaphysis, whole metaphysis, and metaphyseal trabecular bone, compared to WT female quail. Although BBS and BMD became similar between the 2 groups at 4 mo of age, higher TV and TS in whole metaphysis and higher BMC and TV in whole diaphysis of MSTN mutant group compared to those of WT group suggested that the improved tibia bone quality by MSTN mutation before sexual maturation lasted to a certain degree even after sexual maturation. The use of the MSTN mutant female model provided new insights into genetic regulation on female quail bone quality depending on physiological changes.

Effects of a myostatin mutation in Japanese quail (Coturnix japonica) on the physicochemical and histochemical characteristics of the pectoralis major muscle.

The aim of this study was to compare the carcass, meat quality, and histochemical characteristics of pectoralis major (PM) muscle between wild type (WT) and myostatin (Mstn) homozygous mutant (HO) quail lines. The HO quail line exhibited significantly heavier body weight (HO vs. WT, 115.7 g vs. 106.2 g, approximately 110%) and PM muscle weight (HO vs. WT, 18.0 g vs. 15.2 g, approximately 120%) compared to the WT (p < 0.001). However, the two groups had similar traits (pH, redness, yellowness, and drip loss) for meat quality, although slightly higher lightness and cooking loss were observed in the mutant quail (103% and 141%, respectively, p < 0.05). For histochemical traits of PM muscle, Mstn mutant quail exhibited lower type IIA and higher type IIB percentage in the deep region than WT quail (p < 0.05), indicating a fiber conversion from the type IIA to IIB. However, the two quail lines had comparable histochemical traits in the superficial region (p > 0.05). These data suggest that Mstn mutation greatly increases muscle mass without significantly affecting meat quality.

Short communication: In ovo injection of all-trans retinoic acid causes adipocyte hypertrophy in embryos but lost its effect in posthatch chickens.

The regulation of adipose deposition in broiler chickens is an important factor for production efficiency to poultry producers and health concerns to customers. Although vitamin A and its metabolite [all-trans retinoic acid (atRA)] have been used for studies on adipogenesis in mammals and avian, effects of embryonic atRA on adipose development in embryonic (E) and posthatch (D) ages in broiler chickens have not been studied yet. Different concentrations of atRA (0 M-2 µM) were injected in broiler eggs at E10, and adipose tissues were sampled at E16. Percentages of adipose tissues in chicken embryos were significantly increased in the group injected with 500 nM of atRA compared to the 0 M group (P < 0.05). In addition, the adipocyte cross-sectional area (CSA) was significantly greater by in ovo injection of 500 nM atRA compared to the injection of 0 M (P < 0.01). Moreover, in ovo atRA-injected embryos were hatched and BWs were measured at D0, D7, and D14. BWs were not different from those of the 0 M group. Percentages of adipose tissues and CSA of the in ovo atRA-injected group (500 nM) were not different from those of the 0 M group at D14. Taken together, the current study clearly showed that in ovo injection of atRA promoted adipose deposition with hypertrophy during embryonic development, but its effects were not maintained in early posthatch age in broiler chickens, implying that embryonic atRA has an important role in the regulation of adipose development in chicken embryos.

On the relationship between occlusion times and in-car glance durations in simulated driving.

Drivers have spare visual capacity in driving, and often this capacity is used for engaging in secondary in-car tasks. Previous research has suggested that the spare visual capacity could be estimated with the occlusion method. However, the relationship between drivers' occlusion times and in-car glance duration preferences has not been sufficiently investigated for granting occlusion times the role of an estimate of spare visual capacity. We conducted a driving simulator experiment (N = 30) and investigated if there is an association between drivers' occlusion times and in-car glance durations in a given driving scenario. Furthermore, we explored which factors and variables could explain the strength of the association. The findings suggest an association between occlusion time preferences and in-car glance durations in visually and cognitively low demanding unstructured tasks but that this association is lost if the in-car task is more demanding. The findings might be explained by the inability to utilize peripheral vision for lane-keeping when conducting in-car tasks and/or by in-car task structures that override drivers' preferences for the in-car glance durations. It seems that the occlusion technique could be utilized as an estimate of drivers' spare visual capacity in research - but with caution. It is strongly recommended to use occlusion times in combination with driving performance metrics. There is less spare visual capacity if this capacity is used for secondary tasks that interfere with the driver's ability to utilize peripheral vision for driving or preferences for the in-car glance durations. However, we suggest that the occlusion method can be a valid method to control for inter-individual differences in in-car glance duration preferences when investigating the visual distraction potential of, for instance, in-vehicle infotainment systems.

Research Note: Growth promoting potential in Mstn mutant quail dependent and independent of increased egg size.

In avian species, positive relationships between egg weight (EW) and body weight (BW) have been reported. However, the correlation between the body growth rate and different weights of eggs from genetically mutated avian species was not studied yet. Myostatin (Mstn), an anti-myogenic factor, mutant quail were recently developed, and it was reported that EW produced from Mstn homozygous mutant quail (HO) was heavier compared to those from wild-type quail (WT). In the current study, distributions of pre-incubated EW and associations between EW and BW were compared between the Mstn mutant and WT quail lines. Average egg weight for the HO group was significantly heavier than the WT (P < 0.001) and the number of eggs having heavier EW (over 11 g) was higher in the HO compared to the WT (P < 0.01). BWs at wk (W) 0, 4, and 6 after hatch were also significantly greater in the HO (P < 0.001 in all groups). In addition, linear regression analyses revealed positive relationships between EW and BW from W0 to W6, regardless of sexes and genotypes. Furthermore, Mstn mutant quail were a heavier BW compared to the WT quail originated from eggs with similar weights. These data indicate that increased BW by Mstn mutation is contributed by increased EW and/or growth promoting activity of Mstn mutation independent of increasing egg sizes. These findings provide Mstn as a desirable genetic factor for selection of poultry breeds with superior growth. In addition, the knowledge gained from this study could inspire similar proof-of-concept studies involving standard and commercial lines of poultry.

Generation of genome-edited chicken and duck lines by adenovirus-mediated in vivo genome editing.

Conventional avian genome editing is mediated by isolation, culture, and genome editing of primordial germ cells (PGCs); screening and propagating the genome-edited PGCs; and transplantation of the PGCs into recipient embryos. The PGC-mediated procedures, however, are technically difficult, and therefore, the conventional method has previously been utilized only in chickens. Here, we generated germline mosaic founder chicken and duck lines without the PGC-mediated procedures by injecting an adenovirus containing the CRISPR-Cas9 system into avian blastoderms. Genome-edited chicken and duck offspring produced from the founders carried different insertion or deletion mutations without mutations in the potential off-target sites. Our data demonstrate successful applications of the adenovirus-mediated method for production of genome-edited chicken and duck lines.

Loss of Monoallelic Expression of IGF2 in the Adult Liver Via Alternative Promoter Usage and Chromatin Reorganization.

In mammals, genomic imprinting operates via gene silencing mechanisms. Although conservation of the imprinting mechanism at the H19/IGF2 locus has been generally described in pigs, tissue-specific imprinting at the transcript level, monoallelic-to-biallelic conversion, and spatio-temporal chromatin reorganization remain largely uninvestigated. Here, we delineate spatially regulated imprinting of IGF2 transcripts, age-dependent hepatic mono- to biallelic conversion, and reorganization of topologically associating domains at the porcine H19/IGF2 locus for better translation to human and animal research. Whole-genome bisulfite sequencing (WGBS) and RNA sequencing (RNA-seq) of normal and parthenogenetic porcine embryos revealed the paternally hypermethylated H19 differentially methylated region and paternal expression of IGF2. Using a polymorphism-based approach and omics datasets from chromatin immunoprecipitation sequencing (ChIP-seq), whole-genome sequencing (WGS), RNA-seq, and Hi-C, regulation of IGF2 during development was analyzed. Regulatory elements in the liver were distinguished from those in the muscle where the porcine IGF2 transcript was monoallelically expressed. The IGF2 transcript from the liver was biallelically expressed at later developmental stages in both pigs and humans. Chromatin interaction was less frequent in the adult liver compared to the fetal liver and skeletal muscle. The duration of genomic imprinting effects within the H19/IGF2 locus might be reduced in the liver with biallelic conversion through alternative promoter usage and chromatin remodeling. Our integrative omics analyses of genome, epigenome, and transcriptome provided a comprehensive view of imprinting status at the H19/IGF2 cluster.

Transdifferentiation of Myoblasts Into Adipocytes by All-Trans-Retinoic Acid in Avian.

Increased adipogenesis in muscle tissues is related to metabolic syndromes and muscle weakness in humans and improvement of meat quality in animal production. With growing evidence for pro-adipogenic functions of all-trans-retinoic acid (atRA), the current study investigated whether atRA can transdifferentiate myoblasts into adipocytes using a quail myogenic cell line (QM7) and avian primary myoblasts. atRA increased cytoplasmic lipid droplet accumulation and mRNA expression for adipogenic genes in these cells. An acute induction of Pparγ expression by atRA under cycloheximide treatment indicated a direct regulation of Pparγ by atRA. In addition, the induction of Pparγ expression was mediated by retinoic acid receptors . At high levels of Pparγ by atRA, BADGE, an antagonist of Pparγ, inhibited, and rosiglitazone, an agonist of Pparγ, further enhanced atRA-induced transdifferentiation. However, at very low levels of Pparγ in the absence of atRA treatment, rosiglitazone could not induce transdifferentiation of avian myoblasts. These data suggest that the induction of Pparγ expression by atRA is an essential molecular event in myoblasts for atRA-induced transdifferentiation into adipocytes. Based on our findings, atRA can be a new transdifferentiation factor of myoblasts to adipocytes, providing a potential nutrient to enhance marbling in poultry.

Differential Expression of MSTN Isoforms in Muscle between Broiler and Layer Chickens.

Myostatin (Mstn)-A, the main isoform among Mstn splicing variants, functions as a negative regulator, whereas Mstn-B functions as a positive regulator in muscle development. Because broiler chickens are a fast-growing breed raised for meat production and layer chickens are a slow-growing breed raised for egg production, differences in the expression of Mstn isoforms between the two distinct breeds were analyzed in this study. There was no difference in the expression levels of total Mstn (Mstn-A and -B forms) during embryonic development and at D33 between the two breeds. Interestingly, the ratios of Mstn-B to -A were significantly higher in the broiler compared to the layer at most ages. In pectoralis major muscle (PM) tissue, the cross-sectional area (CSA) of muscle fiber was significantly greater in the broiler. The broiler also showed greater bundle CSA and a similar fiber number per bundle compared to the layer at D5 and D33. These data suggest that the greater bundle CSA with myofiber hypertrophy in the broilers is associated with greater muscle growth. The relationship between the expression of Mstn isoforms and growth rate can be used as a potential genetic marker for the selection of higher muscle growth in chickens.

Preclinical testing of an anal bulking agent coated with a zwitterionic polymer in a fecal incontinence rat model.

Fecal incontinence is a disabling condition in which the passage of fecal material cannot be controlled. Although the condition is not life-threatening, it can seriously reduce the quality of life of a patient by isolating them from others. Though various surgical treatments are available for moderate to severe symptoms, a bulking agent is a minimally invasive technique that has attracted attention because of its safety and simple treatment process. However, the biocompatibility of bulking agent materials remains a central issue, with their durability questioned because immune responses and/or the circulatory system may remove the bulking agent in vivo. This study investigated a bulking agent composed of polydimethylsiloxane and hyaluronic acid as a microfiller and carrier gel, respectively. To improve the injectability of the bulking agent, the filler size was tuned using a suspension-based fabrication technique. To evade immune responses, the filler surface was treated with a zwitterionic polymer that simultaneously functionalized and stabilized the material interfaces. The resulting bulking agent exhibited good injectability and biocompatibility in vitro, with 58% lower protein adsorption and no cytotoxicity, leading to an improved bulking effect in a preclinical rat model compared with a bulking agent without surface treatment. These results illustrate the promising potential of bulking agents as a therapy for fecal incontinence with reduced foreign body reactions and long-lasting efficacy.

Injectable polydimethylsiloxane microfiller coated with zwitterionic polymer for enhanced biocompatibility.

Silicone-based fillers have been applied in several branches of medicine, such as soft tissue augmentation, because of their stability and durability. However, the inherently hydrophobic surfaces of silicone occasionally cause excessive deposition of the fibrous matrix in vivo, leading to severe fibrosis. In this study, we evaluated the use of a zwitterionic copolymer to offer a facile surface treatment method for silicone-based fillers and performed a preclinical trial of the formulation as-prepared. The copolymer has amphiphilic moieties, which act as macromolecular surfactants that can functionalize and stabilize the silicone particles during fabrication. The effectiveness and safety of the particle filler were evaluated histologically by scoring the peri-implant tissues into previously defined categories. Our results suggest that zwitterion-coated silicone fillers can inhibit protein adsorption, and thus, help attenuate foreign body reactions in a rat model. This demonstrates their potential for wide application in different fields within the discipline of medicine.

Increased sizes and improved qualities of tibia bones by myostatin mutation in Japanese quail.

Production of large amounts of meat within a short growth period from modern broilers provides a huge economic benefit to the poultry industry. However, poor bone qualities of broilers caused by rapid growth are considered as one of the problems in the modern broilers industry. After discovery and investigation of myostatin (MSTN) as an anti-myogenic factor to increase muscle mass by targeted knockout in various animal models, additional positive effects of MSTN mutation on bone qualities have been reported in MSTN knockout mice. Although the same beneficial effects on muscle gain by MSTN mutation have been confirmed in MSTN mutant quail and chickens, bone qualities of the MSTN mutant birds have not been investigated, yet. In this study, tibia bones were collected from MSTN mutant and wild-type (WT) quail at 4 months of age and analyzed by Micro-Computed Tomography scanning to compare size and strength of tibia bone and quality parameters in diaphysis and metaphysis regions. Length, width, cortical thickness, and bone breaking strength of tibia bones in the MSTN mutant group were significantly increased compared to those of the WT group, indicating positive effects of MSTN mutation on tibia bone sizes and strength. Furthermore, bone mineral contents and bone volume of whole diaphysis, diaphyseal cortical bone, whole metaphysis, and metaphyseal trabecular and cortical bones were significantly increased in the MSTN mutant group compared to the WT group, indicating increased mineralization in the overall tibia bone by MSTN mutation. Especially, higher bone mineral density (BMD) of whole diaphysis, higher total surface of whole metaphysis, and higher BMD, trabecular thickness, and total volume of metaphyseal trabecular bones in the MSTN mutant group compared to the WT group suggested improvements in bone qualities and structural soundness of both diaphysis and metaphysis regions with significant changes in trabecular bones by MSTN mutation. Taken together, MSTN can be considered as a potential target to not only increase meat yield, but also to improve bone qualities that can reduce the incidence of leg bone problems for the broiler industry.

Effects of Myostatin Mutation on Onset of Laying, Egg Production, Fertility, and Hatchability.

Increased body weight and muscle mass, along with improved feed efficiency, by myostatin (MSTN) mutation in quail, supports the potential use of MSTN as a selection marker for higher meat yield in the poultry industry. Although economically important traits of broilers have been studied using recently generated MSTN mutant quail, the effect of MSTN mutation on egg production has not yet been investigated. In this study, several economically important traits of layers, including egg production, reproduction, and body composition of hens, were compared between MSTN homozygous mutant, heterozygous mutant, and wild-type (WT) quail. In terms of egg production, MSTN homozygous mutant quail, showing significantly delayed onset of egg laying, laid significantly heavier eggs, but a significantly lower number of eggs compared to WT quail for 20 days after 3 months of age, resulting in similar total egg production among groups. In addition, the percentage proportion of egg white and yolk in egg weight were similar among groups. Furthermore, similar fertility and hatchability of eggs from MSTN homozygous mutant breeding pairs and WT breeding pairs indicated normal reproductive function of MSTN mutant quail. These findings will provide scientific rationales for the consideration of MSTN as a potential selection marker for layers in the poultry industry.

Research Note: Adipogenic differentiation of embryonic fibroblasts of chicken, turkey, duck, and quail in vitro by medium containing chicken serum alone.

The study of adipogenesis is one of the most important areas for not only regulating meat quality, but production efficiency associated with fat accretion in the poultry species. Current in vitro models for avian adipogenesis require adipogenic inducers including dexamethasone, 3-isobutyl-1-methylxanthine (IBMX), fatty acids, or insulin. However, problems still remain in these models for testing/screening potential nutritional, hormonal, and pharmaceutical factors because of interfering/overriding effects of the inducing factors. Therefore, the purpose of this study was to develop a simple in vitro method for avian adipogenesis. In this study, chicken serum (CS) and fetal bovine serum (FBS) were compared for adipogenic potential using chicken embryonic fibroblasts (CEF). Oil-red O staining at 4 d in culture of CEF under CS revealed that lipid droplet formation was increased by CS in a dose-dependent manner (0 to 10%). On the contrary, all concentrations of FBS (0 to 10%) alone did not show lipid droplet formation. In accordance with the morphological data of CEF, mRNA expression of genes involved in adipocyte differentiation/determination, fatty acid uptake, and triacylglycerol (TAG) synthesis, were most significantly up-regulated by 10% CS at d 4 compared to 1 or 5% CS. In addition, embryonic cells isolated from quail (QEF) at E5, duck (DEF) at E6, and turkey (TEF) at E6, were tested for adipogenic differentiation by media containing the same concentrations of CS. Similar to the morphological data from CEF, quantitative data of the Oil-red O staining showed that lipid droplet formation in QEF, DEF, and TEF was increased by CS in a dose-dependent manner (0 to 10%). The current study demonstrates that CS alone can induce adipogenesis on embryonic fibroblasts of various poultry species. By providing a new simple in vitro method of avian adipogenesis, diverse nutritional, hormonal, and pharmaceutical factors can be broadly and easily tested for scientific and industrial purposes.