Stages Of Egg Production Research Articles

Association analysis of production traits of Japanese quail (Coturnix japonica) using restriction-site associated DNA sequencing

This study was designed to perform an association analysis and identify SNP markers associated with production traits of Japanese quail using restriction-site-associated DNA sequencing. Weekly body weight data from 805 quail were collected from hatching to 16 weeks of age. A total number of 3990 eggs obtained from 399 female quail were used to assess egg quality traits. Egg-related traits were measured at the beginning of egg production (first stage) and at 12 weeks of age (second stage). Five eggs were analyzed at each stage. Traits, such as egg weight, egg length and short axes, eggshell strength and weight, egg equator thickness, yolk weight, diameter, and colour, albumen weight, age of first egg, total number of laid eggs, and egg production rate, were assessed. A total of 383 SNPs and 1151 associations as well as 734 SNPs and 1442 associations were identified in relation to quail production traits using general linear model (GLM) and mixed linear model (MLM) approaches, respectively. The GLM-identified SNPs were located on chromosomes 1–13, 15, 17–20, 24, 26–28, and Z, underlying phenotypic traits, except for egg and albumen weight at the first stage and yolk yellowness at the second stage. The MLM-identified SNPs were positioned on defined chromosomes associated with phenotypic traits except for the egg long axis at the second stage of egg production. Finally, 35 speculated genes were identified as candidate genes for the targeted traits based on their nearest positions. Our findings provide a deeper understanding and allow a more precise genetic improvement of production traits of Galliformes, particularly in Japanese quail.

The Effect of Adding Moringa Leaf Powder to the Adapted Quail Diet During the Egg Production Stage on the Productive Performance and some Biochemical Blood Characteristics

The current experiment was carried out at the poultry farm of the Animal Production department, College of Agriculture, University of Kirkuk from 5/12/2021 until 1/2/2022. To study the effect of different levels of Moring leaves powder (2.5, 5.0, and 7.5)% on the production diet. Forty-eight quail were used at 30 days old and randomly allocated to four treatment groups with each treatment three replication with 4 birds each. The egg weight of the birds was weighed daily with a sensitive electronic balance (0.01) g. The feed intake was determined by weighing the bucket and feed before and after consumption before the next refilling of the bucket. Egg production was monitored daily and recorded for each replicate. The external egg traits were measured by using a clipper vernier (0.01) mm. and the internal egg traits were measured by using an electronic balance (0.01) g. General linear model (GLM) within the SAS program was used to calculate mean, standard error, and significance. Duncan’s multiple range test was used to test the differences between the means. The egg production and feed intake significantly differed between the treatments, it was highest in treatment four and lower production in the control group. The egg weight, egg mass, and feed conversion were non-significant between the treatments. All the external and internal egg traits were non-significant between the groups.

Impact of Dietary Supplementation of Cysteamine on Egg Taurine Deposition, Egg Quality, Production Performance and Ovary Development in Laying Hens.

This study aimed to examine the effect of dietary cysteamine on yolk taurine content in hens during different egg production periods. In Exp. 1, China Agricultural University-3 (CAU-3) hens at the peak stage of egg production (aged 31 wks) were used to explore the effect of diets supplemented with 0.1% cysteamine on yolk taurine content, egg quality and production performance. In Exp.2, two breeds of hens (half Hy-Line Brown and half CAU-3 hens) at the late stage of egg production (68 wks) were used to investigate the influence of diets supplemented with 0, 0.02%, 0.04%, 0.08% or 0.10% cysteamine on yolk taurine content, egg quality, production performance and ovary development. In Exp.1, diets supplemented with 0.1% cysteamine significantly increased yolk taurine content (p < 0.05) without negative influence on production performance or egg quality. In Exp.2, the highest yolk taurine content was observed when cysteamine was supplemented at 0.08% (p < 0.001). However, supplemental cysteamine linearly or quadratically decreased production performance over the first few weeks of feeding, and the effects disappeared with continued feeding (p < 0.05). In conclusion, this study indicated that cysteamine supplementation benefits yolk taurine deposition in hens at both peak and late stage of egg production, but hens at the late stage of egg production show depressed production performance and egg quality.

Effect of Use Different of L-Carnitine on Productive Performance on Egg of Two Breeds of Japanese Quail

This study was conducted on 270 quail females at the age of 42 days from two strains of Japanese quail, the desert and white, in order to show the effect of the strain and the levels of carnitine (0,200,250) mg carnitine/kg feed by three treatments and three replicates for each strain during the egg production stage (42-101) days. The results of study showed that there was a significant difference (p≤0.05) for the effect of strain on the number of eggs, the ratio of egg production HD%, the height of albumen, and the height of yolk, while there were no significant differences in egg weight, total egg mass, egg white ratio, yolk ratio, shell ratio shell thickness, yolk diameter, feed consumption rate, and feed conversion efficiency and mortlity ratio. The results showed, in relation to the effect of carnitine levels, that there were a significant differences (p≤0.05) in the characteristics of egg weight, total egg number, total egg mass, HD% egg albumen height, and yolk diameter, while the differences were not significant in the characteristics of whiteness and yolk ratio, shell, thickness of shell,, feed consumption rate (g/bird), feed conversion efficiency g/g egg, and mortality ratio. As for the effect of the interaction between the quail strains and three levels of carnitine, the results of the statistical analysis showed that there were significant differences (p≤0.05) in the egg weight, the number and the mass of the total egg, HD%, the ratio of whiteness, yolk, shell, height and diameter of the albumen, feed consumption rate, and feed conversion efficiency, while the difference were not significant in the ratio of yolk, thickness of shell, height of yolk and the ratio of mortality

An Initial Study on the Use of Machine Learning and Radio Frequency Identification Data for Predicting Health Outcomes in Free-Range Laying Hens.

Maintaining the health and welfare of laying hens is key to achieving peak productivity and has become significant for assuring consumer confidence in the industry. Free-range egg production systems represent diverse environments, with a range of challenges that undermine flock performance not experienced in more conventional production systems. These challenges can include increased exposure to parasites and bacterial or viral infection, along with injuries and plumage damage resulting from increased freedom of movement and interaction with flock-mates. The ability to forecast the incidence of these health challenges across the production lifecycle for individual laying hens could result in an opportunity to make significant economic savings. By delivering the opportunity to reduce mortality rates and increase egg laying rates, the implementation of flock monitoring systems can be a viable solution. This study investigates the use of Radio Frequency Identification technologies (RFID) and machine learning to identify production system usage patterns and to forecast the health status for individual hens. Analysis of the underpinning data is presented that focuses on identifying correlations and structure that are significant for explaining the performance of predictive models that are trained on these challenging, highly unbalanced, datasets. A machine learning workflow was developed that incorporates data resampling to overcome the dataset imbalance and the identification/refinement of important data features. The results demonstrate promising performance, with an average 28% of Spotty Liver Disease, 33% round worm, and 33% of tape worm infections correctly predicted at the end of production. The analysis showed that monitoring hens during the early stages of egg production shows similar performance to models trained with data obtained at later periods of egg production. Future work could improve on these initial predictions by incorporating additional data streams to create a more complete view of flock health.

Anatomy of the miniature four-legged mite Achaetocoptes quercifolii (Arachnida: Acariformes: Eriophyoidea)

Miniaturization is one of the important trends in the evolution of terrestrial arthropods. In order to study adaptations to microscopic sizes, the anatomy of the smallest insects was previously studied, but not the anatomy of the smallest mites. Some of the smallest mites are Eriophyidae. In this study we describe for the first time the anatomy of the mite Achaetocoptes quercifolii, which is about 115 μm long. For this purpose, we used light, scanning, and transmission electron microscopy and performed 3D reconstructions. The anatomy of A. quercifolii is compared with the anatomy of larger representatives of Eriophyoidea. Despite the small size of the studied species, there is no considerable simplification of its anatomy compared to larger four-legged mites. A. quercifolii has a number of miniaturization effects similar to those found in microinsects: a strong increase in the relative volume of the reproductive system, an increase in the relative volume of the brain, reduction in the number and size of cells of the nervous system. As in some larger four-legged mites, A. quercifolii undergoes midgut lysis at the stage of egg production. On the other hand, in A. quercifolii a greater number of opisthosomal muscles are preserved than in larger gall-forming four-legged mites.

Utilisation of locust bean (Parkia biglobosa) pulp as a natural egg quality enhancer in laying hens

Abstract This study was carried out to improve commercial egg production using parkia pulp which is usually washed off during the processing of parkia seed into spice. A total of 54 Hyline brown Agrited brand pullets were randomly allotted to 3 treatments, 6 birds per replicate. Parkia pulp was included in the birds’ drink (0%, 1%, and 2% parkia pulp) from 08:00 h to 10:00 h followed by clean cool water daily from day 147 to day 245 (early egg production phase). At day 420 to 448 (late egg production phase) conventional multivitamins, 1% and 2% parkia pulp were included in drinking water for 3 days in a week 08:00 h to 17:00 h. Data on the growth of birds, egg production, and egg internal and external quality were measured and analysed using ANOVA at p &lt; 0.05. The weight of birds in the early egg production phase was directly proportional to the quantity of parkia pulp included in the parkia pulp drink. The number of eggs produced per bird (64.85) was significantly higher from the birds on 1% parkia pulp drink, whereas from the egg quality indicators, egg weight (65.03 g), length (56.15 mm), shell weight (8.06 g), and albumen weight (41.75 g) were all significantly higher at 2% inclusion level of parkia pulp drink in the early stage of egg production. In the late phase there was no significant difference among the treatments in the internal and external egg qualities but the weight of birds on parkia drink was high at p ≤ 0.05. The results of our study show that parkia pulp inclusion in commercial laying hen drink enhances the quality and quantity of egg production.

Effects of Energy and Protein Levels on Laying Performance, Egg Quality, Blood Parameters, Blood Biochemistry, and Apparent Total Tract Digestibility on Laying Hens in an Aviary System.

This study was performed to investigate the effects of apparent metabolizable energy (AMEn) and protein levels on laying performance, egg quality, blood parameters, blood biochemistry, and apparent total tract digestibility of energy and nutrients in diets fed to laying hens in an aviary system. A total of 560 Hy-Line Brown laying hens (age = 30 week) were distributed in a completely randomized experimental design in 2 × 2 factorial arrangements with 2 metabolizable energy levels (2700 and 2800 kcal AMEn/kg) and 2 protein levels (16.5 and 14.5% CP). Four treatments and four replicates of 40 birds each (stocking density = 15 birds/m2) were prepared. Results revealed no significant interaction between AMEn and CP in the diet in terms of egg production, floor eggs, broken and dirty egg production, egg mass, feed intake, and feed conversion ratio of laying hens. However, egg weight was affected. As dietary energy and CP levels (2800 kcal of AMEn/kg and 16.5% CP) increased, egg weight increased (p &lt; 0.05). Egg weight, feed intake, and feed conversion ratio significantly differed (p &lt; 0.05) as the energy content in the feed increased. Ether extract significantly varied (p &lt; 0.05) as the energy content in the feed increased. In conclusion, laying performance and egg quality of Hy-Line Brown laying hens in the middle stage of egg production (30 to 50 weeks) were not affected by different dietary energy and protein levels, but feed intake decreased with an increasing level of AMEn in diets. Ether extract significantly varied as the energy content in the feed increased.

The transcriptomic signature of obligate parthenogenesis.

Investigating the origin of parthenogenesis through interspecific hybridization can provide insight into how meiosis may be altered by genetic incompatibilities, which is fundamental for our understanding of the formation of reproductive barriers. Yet the genetic mechanisms giving rise to obligate parthenogenesis in eukaryotes remain understudied. In the microcrustacean Daphnia pulex species complex, obligately parthenogenetic (OP) isolates emerged as backcrosses of two cyclically parthenogenetic (CP) parental species, D. pulex and D. pulicaria, two closely related but ecologically distinct species. We examine the genome-wide expression in OP females at the early resting egg production stage, a life-history stage distinguishing OP and CP reproductive strategies, in comparison to CP females of the same stage from the two parental species. Our analyses of the expression data reveal that underdominant and overdominant genes are abundant in OP isolates, suggesting widespread regulatory incompatibilities between the parental species. More importantly, underdominant genes (i.e., genes with expression lower than both parentals) in the OP isolates are enriched in meiosis and cell-cycle pathways, indicating an important role of underdominance in the origin of obligate parthenogenesis. Furthermore, metabolic and biosynthesis pathways enriched with overdominant genes (i.e., expression higher than both parentals) are another genomic signature of OP isolates.

Influence of age and sex on the blood biochemical constituent values of broiler breeders during the egg-laying stage.

This study aimed to evaluate the influence of age and sex on the blood biochemical constituents of broiler breeders during the egg production stage. The analysis was performed in an industrial broiler breeder farm, and blood samples were collected from males and females at five different ages. Biochemical elements analysed in each serum sample were total proteins, albumin, globulins, uric acid, total cholesterol and triglycerides, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), creatine kinase (CK), alkaline phosphatase (PAL), calcium and phosphorus, beside the glycaemic status. At most ages, females had higher values of total proteins, albumin, globulins, triglycerides, cholesterol, glucose, calcium, phosphorus, Ca/P (calcium and phosphorus) ratio and gamma-glutamyltransferase (GGT). The values of uric acid, aspartate aminotransferase (AST), creatine kinase (CK) and alkaline phosphatase (PAL) were higher in males. The lowest protein values were found at 28 and 60 weeks old. The mean albumin values were significantly higher at 44 and 52 weeks old in males and females. A trend of increasing globulin values with increasing age up to 52 weeks old was observed. Although calcium and phosphorus did not vary according to age, the Ca/P ratio was lowest at 36 weeks old. Comparing the means of both sexes, the AST and GGT values were significantly higher in 60-week-old birds. The highest serum levels of CK occurred at 28 and 52 weeks old. The physiological levels of serum biomarkers presented in this work are important for evaluating productivity performance, welfare and disease indication in breeding flocks.

Effect of Substitution Millet Energy Instead of Yellow Corn Energy on Growth and Production Diet in Partridge

The research was carried out in the Livestock Research Division / Nineveh Research Department using 720 birds at one-day-old, distributed on four substitution millet energy 0% (control), 20%, 30%, and 40% instead of corn energy, to study its effect on the growth and production periods for partridge. The results showed that the 30% substitution treatment was significantly superior (P <0.05) on control treatment in body weight, Also, in feed consumption, the three treatments were significantly superior (P < 0.05) on control treatment, while there was no significant difference between the four treatments for weight gain and food conversion ratio in the starter period (1-4) weeks of age. As for the growth period (5-24) weeks, a significant decrease (P <0.05) in body weight is observed with an increase in the millet replacement percentage, the control treatment was significantly superior (P <0.05) on the 30% substitution treatment in the weight gain, whereas the control treatment, decreased significantly (P <0.05) from the substitution treatment 40% in the feed consumption and food conversion ratio. As for the egg production stage, the control treatment was significantly superior (P <0.05) on 20% and 40% treatments in the number and percentage of eggs, the feed consumed was not affected by the treatments under study, while there was a significant difference (P <0.05) between the age of 26 weeks and the age of 33 weeks in feed consumption, Control treatment decreased significantly (P <0.05) from substitution treatment 20% in FCR / Dozen egg. the treatment of substitution 30% increased significantly (P <0.05) on control treatment for hatching%, fertility% and hatching from fertilized eggs%.

A genome-wide single nucleotide polymorphism scan reveals genetic markers associated with fertility rate in Chinese Jing Hong chicken

The function of the sperm storage tubules is directly correlated with the fertility of laying hens. However, little is known about the molecular mechanisms regulating the fertility traits in chicken. To identify genetic markers associated with reproductive traits, we calculated fertility rate at 61 to 69 wk (51 D) of Jing Hong chickens parent generation as the phenotype and the genotype were detected by the chicken 600K Affymetrix Axiom High Density single nucleotide polymorphisms (SNP)-array. The genome-wide association study using 190 Jing Hong hens showed that the 20 SNP in chromosomes 3 and 13 were significantly associated with fertility rate. To verify these results, a total of 1900 Jing Hong laying hens from 2 populations (P1 and P2) were further genotyped by polymerase chain reaction–restriction fragments length polymorphisms method. The association analysis results revealed that 12 polymorphisms (AX-75769978, AX-76582632, AX-75730546, AX-75730496, AX-75730588, AX-76530282, AX-76530329, AX-76529310, AX-75769906, AX-75755394, AX-80813697 and AX-76582809) out of 20 showed highly significant effects (P < 0.0001) on fertility rate in P1, P2 and P1+P2. Six haplotypes (TTAA, TTGG, TTAG, CTAA, CTGG, and CTAG) were inferred based on significant loci (AX-75730546 and AX-76530282) also showed significant association with fertility rate, where haplotype CTAG was shown to be markedly associated with the significantly highest (P < 0.0001) fertility rate (in P1, 86.42 ± 0.59; P2, 85.98 ± 0.59 and P1+P2, 86.16 ± 0.42) followed by other haplotypes for the irrespective of population studied. Collectively, we report for the first time that 12 SNP in the chromosomes 3 and 13 were significantly associated with fertility rate during the later stage of egg production, which could be used as the potential genetic markers that would be able to facilitate in the selection and improvement of fertility rate through chicken breeding.

Effect of the Ration Form on Productive Performance of Three Japanese Quail Breeds

تم تنفيذ الدراسة على (720) فرخا من ثلاث سلالات من السمان الياباني هي الصحراوي والأسود والأبيض لبيان تأثير السلالة وثلاثة أشكال للعليقة هي المجروش والمحبب والمفتت وبواقع ثلاث معاملات وبأربع مكررات لكل سلالة خلال مرحلة النمو (1- 35 يوما)، و324 أنثى من نفس السلالات بواقع ثلاث معاملات وبأربع مكررات لكل سلالة خلال مرحلة إنتاج البيض (42- 101 يوما). أظهرت نتائج البحث وجود فروقات معنوية (P≤0.05) لتأثير السلالة في وزن الجسم الحي والزيادة الوزنية ومعامل تحويل العلف (غم علف: غم زيادة وزنية) و(غم علف: غم ذبيحة) ووزن الذبيحة خلال مرحلة النمو، وفي وزن البيضة خلال مرحلة إنتاج البيض. أما بالنسبة لتأثير شكل العليقة فقد اتضح وجود فروقات معنوية (P≤0.05) لصفات وزن الجسم الحي والزيادة الوزنية ومعامل تحويل العلف (غم علف: غم زيادة وزنية) و(غم علف: غم ذبيحة) ووزن الذبيحة خلال مرحلة النمو، وفي وزن البيضة وكتلة البيض الكلية خلال مرحلة إنتاج البيض. أما تأثير التداخل بين السلالة وشكل العليقة فقد أوضحت نتائج التحليل الإحصائي وجود فروقات معنوية (P≤0.05) في وزن الجسم الحي والزيادة الوزنية ومعامل تحويل العلف (غم علف: غم زيادة وزنية) و(غم علف: غم ذبيحة) ووزن الذبيحة ونسبة التصافي خلال مرحلة النمو، وفي نسبة القشرة ووزن البيضة وعدد البيض الكلي وكتلة البيض الكلية وتركيز الالبومين خلال مرحلة إنتاج البيض. أما ما يخص الحسابات الاقتصادية فقد أظهرت النتائج حصول سلالة السمان الصحراوي على أفضل ربح (دينار عراقي/ كغم وزن حي) خلال مرحلة النمو، بينما حصلت سلالة السمان الأبيض على أفضل ربح (دينار عراقي/ كغم بيض) خلال مرحلة إنتاج البيض. أما أفضل ربح نتيجة تأثير شكل العليقة فقد كان من نصيب العلف المحبب خلال مرحلتي النمو وإنتاج البيض. أما أفضل ربح لمعاملات تداخل السلالة وشكل العليقة فقد كان لتداخل سلالة السمان الصحراوي مع العلف المحبب خلال مرحلة النمو، وتداخل سلالة السمان الأبيض مع العلف المحبب خلال مرحلة إنتاج البيض.

Effects of β-mannanase on Egg Production Performance, Egg Quality, Intestinal Microbiota, Viscosity, and Ammonia Concentration in Laying Hens

ABSTRACT Two experiments were conducted to evaluate the effects of β-mannanase on egg production performance, egg quality, intestinal microbiota, viscosity, and ammonia concentration in laying hens. In Exp. 1, two hundred and seventy 30-wk-old Hy-Line Brown laying hens were assigned to 6 diets arranged in a 3 × 2 factorial of three levels of MEn and CP [(a corn-soybean meal based diet (HEHP), a diet containing 50 kcal of MEn/kg and 1.0% less energy and CP than the HEHP (MEMP), and a diet containing 80 kcal of MEn/kg and 1.5% less energy and CP than HEHP (LELP)], and β-mannanase supplementation (0 or 0.04%). In Exp. 2, A total of two hundred and sixteen62-wk-old Hy-Line Brown laying hens were assigned to 6 dietary treatments in a 3 × 2 factorial arrangement. In Exp. 1, β-mannanase supplementation increased egg production rate in hens fed LELP diet, but not in those fed HEHP or MEMP diet (interaction, p<0.01), and the interaction was significant (p<0.01) for egg mass. β-mannanase supplementation decreased (p<0.05) ammonia concentration. In Exp. 2, the supplementation of β-mannanase increased egg production rate and egg mass in hens fed LELP diet, whereas no differences were found in those fed HEHP or MELP diet (interaction, p<0.01). The supplementation of β-mannanase in a lower energy and protein diet resulted in similar production performance when compared to high-energy and high-protein diet during early and late stages of egg production.

Occurrence of Organochlorine Pesticide (OCP) Residues in Chicken Skin, Liver and Muscle in Egypt

This study was conducted for determination of organochlorine (OCPs) pesticide residues in muscle, skin and liver of chickens (laying hens). The examined samples were collected from three laying hen farms (white Hy- Line breed) in El- Dakahlia, El-Sharkia and El-Giza Governorates, Egypt. Five samples of each tissue were collected at 3 stages; start, peak and end, of egg production from the three farms with the total of 45 samples for each tissue type. The examined samples were extracted and prepared to organochlorine pesticide detection by gas Chromatography system equipped with electron capture detector (ECD). Exactly 14 of organochlorine pesticide residues were analyzed. The obtained results revealed that the Methoxychlor, PP-DDE, Dieldrin, Aldrin, Heptachlor epoxide and α-BHC residues were not detected in all the examined samples. Meanwhile, PP-DDT, PP-DDD, Endrin, Endosulfan, Heptachlor, Δ-BHC, ɤ-BHC (lindane) and ɤ-chlordane were detected in the examined samples in different concentrations. No considerable difference in organochlorine residues could be noticed either between the different Governorates or between the different stages of egg production. The results exhibited relatively higher levels of these residues in skin and liver samples comparing with those in the muscle samples.

Novel Polymorphisms in RAPGEF6 Gene Associated with Egg-Laying Rate in Chinese Jing Hong Chicken using Genome-Wide SNP Scan.

The improvement of egg production is of vital importance in the chicken industry to maintain optimum output throughout the laying period. Because of the elongation of the egg-laying cycle, a drop in egg-laying rates in the late laying period has provoked great concern in the poultry industry. In this study, we calculated the egg-laying rate at weeks 61–69 (60 days) of Jing Hong chickens parent generation as the phenotype, and the genotype were detected by the chicken 600K Affymetrix Axiom High Density (HD) Single Nucleotide Polymorphisms (SNP)-array. The Genome-Wide Association Study (GWAS) result showed that the egg production trait is significantly associated with five SNPs (AX-75745366, AX-75745380, AX-75745340, AX-75745388, and AX-75745341), which are in the rap guanine nucleotide exchange factor 6 (RAPGEF6) gene on chicken chromosome 13. A total of 1676 Chinese commercial Jing Hong laying hens—including two populations, P1 population (858 hens) and P2 population (818 hens)—were genotyped using the Polymerase Chain Reaction-Restriction Fragments Length Polymorphisms (PCR-RFLP) method for the association analysis of egg-laying rates for the verification of the GWAS results. Genotypic and allelic frequencies of five SNPs were inconsistent with Hardy–Weinberg equilibrium, and the average population genetics parameters considering all the SNP values; i.e., gene homozygosity (Ho), gene heterozygosity (He), the effective number of alleles (Ne), and the polymorphism information content (PIC) were 0.75, 0.25, 1.40, and 0.20 in P1; 0.71, 0.29, 1.46, and 0.24 in P2; and 0.73, 0.27, 1.43, and 0.22 in P1 + P2 populations, respectively. The association analysis results revealed that out of the five polymorphisms, three of them (AX-75745366, AX-75745340, and AX-75745341; Patent applying No: 201810428916.5) had highly significant effects on egg-laying rates according to the GWAS results. Population-specific association analyses also showed similar significant association effects with this trait. Four haplotypes (AAGG, AAAG, AGGG, and AGAG) were inferred based on significant loci (AX-75745340 and AX-75745341) and also showed significant associations with the egg-laying rate, where haplotype AAGG had the highest egg-laying rate, with the exception of the egg-laying rate in P1 population, followed by other haplotypes. Furthermore, genotypes TT, AA, and GG showed the highest egg-laying rate compared to the corresponding genotypes at AX-75745366, AX-75745340, and AX-75745341 SNP loci in P1+P2, respectively. A similar result was found in the population-specific analysis except for the P1 population, in which TC genotype showed the highest egg-laying rate. No significant association was found in the egg-laying rate during the 60 days laying period for the SNPs (AX-75745380 and AX-75745388) in any group of population (p ≥ 0.05). Collectively, we report for the first time that 3 SNPs in the RAPGEF6 gene were significantly associated with the egg-laying rate during the later stage of egg production, which could be used as the potential candidate molecular genetic markers that would be able to facilitate in the selection and improvement of egg production traits through chicken breeding.

Effect of Low Tannin Sorghum Based Feed on Physical and Nutritional Quality of Layer Chicken Eggs

This study was carried out to evaluate the effect of replacing maize with low tannin sorghum (LTS) in layer feed on the physical and nutritional quality of eggs of layers at peak egg production stage. One hundred and twenty, 30-weeks old hens were grouped into three blocks of forty birds per block and were subjected to three different diets: 100%Maize, 50%Maize50%LTS and 100%LTS for 8 weeks. Eggs were collected on the 4th and 8th week of feeding trial. The results showed that eggs had statistically similar weights, amounts of protein, fat, Vitamin E and Vitamin A. The colour of egg yolks increased in lightness and reduced in hue and Chroma significantly across all the dietary blocks with increase in LTS while cholesterol content decreased. The saturated fatty acid content in the albumin and yolk oil extract remained constant irrespective of the period of feeding or variation of Maize and LTS content. The Monounsaturated fatty acid content decreased significantly (P=0.0003) during the whole trial diet period. The Polyunsaturated fatty acid content remained constant for the albumin (P=0.4095) while the yolk showed an increase (P=0.1162) from the initial 15.82±0.57 g/100g on the 4th week to 24.05±7.25 g/100g on the 8th week for diets with 100%Maize. 50%M50%LTS increased from 14.59±0.16 to 21.48±4.19 g/100g and 100%LTS had its Polyunsaturated fatty acid content decline from 13.36±0.31 to 10.71±0.32g/100g. This study indicates that LTS can replace Maize as a source of energy in chicken feeds with no adverse effects on the quality of the eggs.

Ovarian transcriptomic analysis of Shan Ma ducks at peak and late stages of egg production.

ObjectiveTo assess the differences in ovarian transcriptomes in Shan Ma ducks between their peak and late stages of egg production, and to obtain new transcriptomic data of these egg-producing ducks.MethodsThe Illumina HiSeq 2000 system was used for high throughput sequencing of ovarian transcriptomes from Shan Ma ducks at their peak or late stages of egg production.ResultsGreater than 93% of the sequencing data had a base quality score (Q score) that was not less than 20 (Q20). From ducks at their peak stage of egg production, 42,782,676 reads were obtained, with 4,307,499,083 bp sequenced. From ducks at their late stage of egg production, 45,316,166 reads were obtained, with 4,562,063,363 bp sequenced. A comparison of the two datasets identified 2,002 differentially expressed genes, with 790 upregulated and 1,212 downregulated. Further analysis showed that 1,645 of the 2,002 differentially expressed genes were annotated in the non-redundant (NR) database, with 646 upregulated and 999 downregulated. Among the differentially expressed genes with annotations in the NR database, 696 genes were functionally annotated in the clusters of orthologous groups of proteins database, involving 25 functional categories. One thousand two hundred four of the differentially expressed genes with annotations in the NR database were functionally annotated in the gene ontology (GO) database, and could be divided into three domains and 56 categories. The three domains were cellular component, molecular function, and biological process. Among the genes identified in the GO database, 451 are involved in development and reproduction. Analysis of the differentially expressed genes with annotations in the NR database against the Kyoto encyclopedia of genes and genomes database revealed that 446 of the genes could be assigned to 175 metabolic pathways, of which the peroxisome proliferator-activated receptor signaling pathway, insulin signaling pathway, fructose and mannose metabolic pathways, gonadotropin releasing hormone signaling pathway and transforming growth factor beta signaling pathway were significantly enriched.ConclusionThe differences in ovarian transcriptomes in Shan Ma ducks between their peak and late stages of egg production were elucidated, which greatly enriched the ovarian transcriptomic information of egg-producing ducks.

Body weight, egg production, and egg quality traits of gray, brown, and white varieties of Japanese quail (Coturnix coturnix japonica) in coastal climatic condition of Odisha.

Aim:The present study was conducted to evaluate the performance of gray, brown, and white varieties of Japanese quail (Coturnix coturnix japonica) with respect to body weight, egg production, and egg quality traits in the coastal climatic condition of Odisha.Materials and Methods:A total of 500-day-old straight run Japanese quail chicks of three varieties, viz., gray, brown, and white were randomly selected and reared in deep litter system at Central Poultry Development Organization, Eastern Region, Bhubaneswar. The weekly body weight of the birds was recorded till their egg production stage (up to 6 weeks of age). The average egg production was recorded every biweekly from 6th to 20th week. Exterior and interior quality of eggs from each variety was determined at 6 weeks of age.Results:The initial average weekly body weight of three varieties did not differ (p>0.05) among the varieties. However, from 1st to 6th week significantly higher body weight was observed in gray than white and brown. Brown varieties had reached 50% egg production 1 week earlier than gray and white. Brown had higher peak hen day (HD) production or hen-housed egg production followed by white and gray. External quality such as: Egg weight, egg length, egg width, volume, shape index, shell weight, shell thickness depicted no significant difference among the varieties except circumference length and circumference width, which were significantly higher (p≤0.05) in gray varieties than brown varieties. Internal egg characteristics such as: Albumen length, albumen width, albumen height, albumen index, yolk length, yolk width, yolk height, yolk index, albumen weight, yolk weight, Haugh unit revealed no significance difference among the varieties.Conclusion:It may be summarized from the findings that gray excelled in body weight followed by white and brown. Egg production potential in terms of hen house egg production or HD egg production was higher for brown followed by white and gray in the coastal climatic condition of Odisha.

Canonical-correlation analysis applied to selection-index methodology in quails

Genetic evaluations in dual-purpose quails (Coturnix coturnix) have demonstrated that overall genetic gains in a breeding program are achieved not only based on a specific trait, but on several. The most common technique to use all this information is the selection index. Another alternative may be the canonical-correlation analysis applied to selection index. There is, however, a lack of studies using canonical correlation in quails. Hence, the objectives of this study were to apply canonical-correlation analysis to estimate the relationship of nine traits and to compare genetic gains obtained by this methodology to desired-gain selection index in three lines of quails. Data for three lines of layer quails consisted of body weight at 28 days (W28), egg weight (EW), age at first egg (AFE) and egg production at 30, 60, 90, 120, 150 and 180 days after onset of lay. Two sets of traits were established: the first one contained predictor variables (W28, EW and AFE) and the second one contained variables related to egg production. A selection index was constructed using the standardized coefficients of canonical covariates as weighting factors when a given canonical correlation was significant. We constructed two desired-gain selection indices: DG-SI1 and DG-SI2. The difference between them is that DG-SI2 had a desired gain for body weight set to 0. The estimated canonical correlations were as follows: 0.811, 0.058 and 0.003 for the yellow, 0.821, 0.181 and 0.076 for the red, and 0.825, 0.117 and 0.038 for the blue line. Only the first pair of canonical variates was significant (P<0.05). AFE and early stages of egg production were very influent and showed great importance in defining the canonical variates and, consequently, the estimated canonical correlations. All lines had, in general, similar results for the canonical analysis indicating that traits that drive management decisions in these lines would be the same. The indices under study showed differences in response to selection; however, they generally resulted in consistent favorable genetic gains. For all lines, the canonical selection index resulted in the lowest AFE and highest egg production at 30 days. The DG-SI1 showed the highest genetic gains for W28 in all lines. There was a general lower genetic gain of other traits for DG-SI1 at the expense of the desired genetic gain for W28. Selection for AFE, according to the canonical-correlation analysis, would have a great impact on the number of eggs produced. Canonical selection index is a good alternative for a desired-gain selection index.