Relationship between plumage color and eggshell patterns with egg production and egg quality traits of Japanese quails

Conservation Genetics and Breeding using Molecular Genetic Markers in Japanese Quail (Coturnix japonica)

BACKGROUND

The Japanese quail (Coturnix japonica) is a small migratory bird whose main habitats are located in East Asia, Russia, China, Japan, Korea, and India. The Japanese quail was first introduced into the Iraqi research sector in the early 1980s. This investigation aimed to identify the genetic divergence between the available genetic lines of the Japanese quail in Iraq as a first step to conducting further conservation and breeding, benefiting from studying the genetic diversity related to productivity, adaptation, and immune susceptibility.

METHODS

In this study, we harnessed the random amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR) protocol to investigate the genetic structure, diversity, and differentiation of seven distinct genetic lines of these birds with white, brown, wild grey, and yellow plumage guided by 20 molecular genetic markers.

RESULTS

Our findings showed a relatively high polymorphism level of these 20 markers, which was adequate for describing genetic variation within and between the quail lines under study. Overall, the pairs of the White male and Brown male, Brown female and Grey male, and Grey female and Grey male lines were the most genetically distant. Conversely, the White male and Grey male lines were the most similar.

CONCLUSIONS

The genetic differences established between these lines can enable us to suggest recommendations for further conservation genetics and breeding of this species. In particular, we propose that choosing animals (lines) with the greatest genetic distances, i.e., the least genetic similarities, can help preserve the highest genetic variability within the population. This proposed approach mirrors many contemporary conservation strategies, and information derived directly from this study can potentially be used to improve breeder selection regimes for additional conservation initiatives ex situ.

A novel codominant plumage color pattern of white breast patches in WugangTong geese was controlled by EDNRB2

Two basic plumage color patterns are observed in adult geese: solid grey (G) or colorless white (W). However, a Chinese indigenous breed, the Wugangtong goose (WGT), continues to be subject to selective breeding efforts as it displays segregation of plumage colors, including G, W, and a novel color pattern designated Wb (G with white breast circles). The underlying genetic mechanisms responsible for the Wb phenotype are yet to be determined. The current study employed the population differentiation index (FST) to analyze 90 geese exhibiting diverse plumage colors, identifying the fifth intron of EDNRB2 as a particularly noteworthy region with the highest FST values. Sanger sequencing of the region surrounding the EDNRB2 gene identified a 14-bp insertion within exon 3 as the causal mutation. The heterozygosity of this 14-bp insertion and wild-type alleles was completely associated with the Wb phenotype, thereby substantiating the codominant nature of the G and W phenotypes. An inter-species corroborated this finding cross between the graylag (no 14-bp insertion) and the swan goose (homozygous for the 14-bp insertion) breeds, as hybrids from this cross exhibited the Wb phenotype. Transcriptomes from white breast patches and gray dorsal skins of 4 Wb geese were compared. A significant downregulation of genes involved in melanin synthesis and melanocyte development was observed, including EDRNB2 and MLANA. The downregulation of MLANA indicated that the mutated EDNRB2 resulted in melanocyte loss in specific body regions, as MLANA is a marker gene for melanocytes. The findings were corroborated by melanin staining using the Mansson-Fontana method, which revealed no melanin particles deposited in the white breast patches. In summary, the gray plumage color was codominant to the white color in WGT geese, and plumage color variations were controlled by EDNRB2. The findings of our study offer valuable and practical guidance for the purification of plumage colors among WGT, whether through traditional phenotype selection or molecular breeding methods.

The relationship between eggshell color, hatching traits, fertility, mortality, and some qualitative aspects of Japanese quail (Coturnix japonica) eggs

Quail, one of the most important sources of meat and eggs, can aid in the reduction of the meat crisis if they are raised and cared for by small farmers. The current study investigated the impact of eggshell color variety on egg quality traits and hatching parameters of Japanese quail Coturnix japonica eggs. Therefore, 1,075 eggs were collected from female quails when they were 10-wk old. These eggs were distributed based on the color of their eggshells into 5 different classifications: eggshell with color type 1, very dark distributed brown spots on brown eggshell; eggshell with color type 2, small black spots on a white eggshell; eggshell with color type 3, widespread brown spots on brown eggshell; eggshell with color type 4, bubble egg, pin dotted on grayish brown color eggshell; and eggshell with color type 5, small brown spots on very clearly white eggshell. The characteristics of hatchability, internal and external egg quality, and the rate of embryonic death were then determined. The results showed that the percentage of fertility and commercial and scientific hatchability was greatly affected by eggshell color. There were also variations in the percentage of hatched chicks', early mortality rates, and late mortality rates based on eggshell color. According to the results of the current study, eggshell color has a significant impact on egg weight, egg width, and percentages of eggshell, yolk, and albumen but has no effect on shape index, egg length, or egg elongation. Based on the results, eggshells with color types 2 and 3 were recommended for use in hatching procedures due to their high levels of fertility (92.01 and 91.63%, respectively), scientific hatchability (82.92 and 83.93%, respectively), commercial hatchability (76.56 and 77.32%, respectively), and hatched chick (5.50 and 6.70, respectively). In addition, the late embryonic mortality rate was 0.00% for eggshells with color type 3. Therefore, the color of the eggshell can be employed as a key factor in guiding the eggs that are produced, whether they are going to be consumed at the table or used for hatching, to make breeding easier.

Analysis of growth performance and carcass and meat quality of different crossbreeds of Cherry Valley duck

Duck breeding and production are facing great opportunities in China, as the market for small-sized high-quality duck is rapidly expanding. Therefore, breeding the most suitable genetic stock has become an important goal.This study assessed body and carcass weight, slaughter rate and meat quality of offspring of three cross combinations; Cherry Valley duck (CV♂) × Small-sized Pekin duck (PK♀), CV♂×Taiwan white duck (TW♀), CV♂×Putian white duck (PT♀) and the corresponding pure lines at 56 d of age. These 420 ducks were raised in seven separate groups (10 pens/group, 3♂+3♀/pen).Body and carcass weights were significantly lower in the three cross combinations than CV ducks (P=0.042 and P=0.012). Abdominal fat and sebum weight were lowest in CV♂×PK♀, whereas the breast and the leg muscle weights were significantly higher in CV♂×PK♀ compared to CV♂×TW♀ and CV♂×PT♀ (P=0.018 and P=0.023). No difference was observed in the visceral tissues among the three cross combinations or compared to CV ducks.The performance indicators suggested that CV♂×PK♀, CV♂×TW♀ and CV♂×PT♀ cross combinations are best suited for segmented duck meat, featured duck meat and whole-duck processing, respectively.

Assessment of variations in productive performance of two different plumage color varieties of Japanese quail and their reciprocal crosses

This study aimed to detect the phenotypic differences between the brown (BB) and white (WW) feathered quails and their reciprocal crosses (BW and WB) over two successive generations. The WW and cross quails, especially the BW, had the heaviest body weights, throughout the studied period, with significant variations between the two studied generations (P<0.05). Moreover, the WW and BW possessed the largest egg production during the F1, while in the F2, the BB had superiority among the studied quails with a prominent superiority of the F2 over the F1 (P<0.05). However, the F1 had higher egg weights than F2 with superiority of WW quails compared to the others (P<0.05). Also, the WW quails had the lowest lipid contents of the eggs. These phenotypic variations among the studied quails might be preliminarily explained by the results of the analyzed microsatellite markers despite the few markers used. The high variability among the BW and WB quails might be due to the larger number of alleles (N_A and N_e) and the lower values of F_IS with low heterozygosity levels (H_O and H_e). Moreover, the BW and BB were the closest, while WB and WW were the farthest because of the high and low genetic identities and the high and low genetic distance between them, respectively. So the obtained results might introduce an initial scientific basis for evaluating and employing the genetic properties of BB, WW, BW, and WB quails in further genetic improvement program, and more microsatellite markers are recommended.

Identification of crucial genes and metabolites regulating the eggshell brownness in chicken

BACKGROUND

Protoporphyrin IX (Pp IX) is the primary pigment for brown eggshells. However, the regulatory mechanisms directing Pp IX synthesis, transport, and genetic regulation during eggshell calcification in chickens remain obscure. In this study, we investigated the mechanism of brown eggshell formation at different times following oviposition, using White Leghorn hens (WS group), Rhode Island Red light brown eggshell line hens (LBS group) and Rhode Island Red dark brown eggshell line hens (DBS group).

RESULTS

At 4, 16 and 22 h following oviposition, Pp IX concentrations in LBS and DBS groups were significantly higher in shell glands than in liver (P < 0.05). Pp IX concentrations in shell glands of LBS and DBS groups at 16 and 22 h following oviposition were significantly higher than WS group (P < 0.05). In comparative transcriptome analysis, δ-aminolevulinate synthase 1 (ALAS1), solute carrier family 25 member 38 (SLC25A38), ATP binding cassette subfamily G member 2 (ABCG2) and feline leukemia virus subgroup C cellular receptor 1 (FLVCR1), which were associated with Pp IX synthesis, were identified as differentially expressed genes (DEGs). RT-qPCR results showed that the expression level of ALAS1 in shell glands was significantly higher in DBS group than in WS group at 16 and 22 h following oviposition (P < 0.05). In addition, four single nucleotide polymorphisms (SNPs) in ALAS1 gene that were significantly associated with eggshell brownness were identified. By identifying the differential metabolites in LBS and DBS groups, we found 11-hydroxy-E4-neuroprostane in shell glands and 15-dehydro-prostaglandin E1(1-) and prostaglandin G2 2-glyceryl ester in uterine fluid were related to eggshell pigment secretion.

CONCLUSIONS

In this study, the regulatory mechanisms of eggshell brownness were studied comprehensively by different eggshell color and time following oviposition. Results show that Pp IX is synthesized de novo and stored in shell gland, and ALAS1 is a key gene regulating Pp IX synthesis in the shell gland. We found three transporters in Pp IX pathway and three metabolites in shell glands and uterine fluid that may influence eggshell browning.