japanese quail

Recently, the consumption of poultry meat, especially quail meat, has increased significantly due to some nutritional features, including high-quality protein and low fat content. This issue has led to an increase in the demand for the production of healthy products. Fat sources are one of the food items needed to provide energy in the poultry diet. Usually, mixed vegetable oils are used in commercial diets. Sesame oil has essential unsaturated fatty acids for poultry, which can have beneficial effects on the growth and health indicators of chickens. The main essential fatty acids in sesame oil include linoleic acid, oleic acid, palmitic acid, and stearic acid. The use of essential fatty acids in the diet of poultry increases their storage in meat and eggs, which can have beneficial effects on human health. Sesame oil contains compounds called lignans, such as sisamin, sisamulin, and small amounts of sisamol, and has many different physiological functions, such as reducing blood fat, reducing the level of arachidonic acid, increasing antioxidant capacity, increasing the bioavailability of gamma-tocopherol, and anti-inflammatory functions. On the other hand, sesame lignans can protect body cells from free radical damage by inhibiting reactive oxygen species. Sesame oil can increase the detoxification of chemicals in the liver and has a protective role against oxidative stress. Considering the antioxidant properties and nutritional compounds in sesame oil, the present study was conducted to investigate the effect of different levels of sesame oil and soybean oil on performance and growth indicators, as well as some serum biochemical parameters, including liver enzymes, profile fat, and proteins, in Japanese quail.

Three hundred quails (Japanese quail) with the age of 10 days were randomly divided into five treatments with three replications (20 quails in each replication) and fed with experimental diets for 42 days. All groups were reared in the same growing and management conditions until 42 days of age. In the experimental treatments, the base diet containing zero (control), 25, 50, 75, and 100% sesame oil was used instead of soybean oil. Growth indices (weight gain, feed consumption, and feed conversion ratio, FCR), the weight of internal organs (liver, heart, gizzard, breast, and thigh muscle), and some serum biochemical parameters were measured at the end of the growing period. Serum biochemical parameters included total protein, albumin, globulin, triglyceride, cholesterol, LDL (low-density lipoprotein), and HDL (high-density lipoprotein). The concentrations of blood parameters were measured by colorimetry (photometry) using commercial kits available in the market and based on the provided instructions. The data were statistically analyzed by SPSS version 22 statistical software with the one-way analysis of variance (ANOVA) test. Statistical analysis was performed at a 95% confidence level.

Feed consumption and FCR decreased by increasing the percentage of sesame oil replacement. The lowest feed consumption during the growing period belonged to the groups receiving 75 and 100% sesame oil, and the highest feed consumption was recorded in the group receiving 100% soybean oil; these two groups showed a significant difference (p < 0.05). No significant difference was seen in the feed consumption between the other groups. The weight gain of quails at the end of the rearing period was not affected by different levels of sesame oil replacement. The comparison of FCR in different treatments showed that the lowest FCR was found in quails fed with 75 and 100% sesame oil, and the highest FCR was seen in quails receiving 100% soybean oil (p < 0.05). There was no significant difference in FCR between the other groups. Different levels of sesame oil and soybean oil did not significantly affect the weight of the internal organs of the studied quails. Total protein, albumin, globulin, and the ratio of albumin to globulin were not significantly different in all groups. Increasing the percentage of sesame oil decreased triglycerides, cholesterol, and LDL and increased HDL. The triglyceride level in the groups receiving 75 and 100% sesame oil was significantly lower than in the quails of the control group and those fed with 25% sesame oil (p < 0.05). Cholesterol levels were significantly lower only in quails receiving 75 and 100% sesame oil than in the other groups (p < 0.05). The LDL level in quails receiving 25 and 50% sesame oil was higher than in those receiving 75 and 100% sesame oil (p < 0.05). HDL also increased with increasing the percentage of sesame oil replacement.

The results of this study showed that replacing sesame oil in the diet can have positive effects on the average daily feed intake and FCR. It seems that unsaturated fatty acids affect the digestibility and formation of fat micelles and lead to the improvement of metabolic energy efficiency, which affects the performance of quails. Furthermore, the addition of sesame oil to the diet improved serum biochemical indices, especially the lipid profile (triglyceride, cholesterol, LDL, and HDL). Probably, the sesamin present in sesame seeds reduces the activity and gene expression of enzymes involved in the synthesis of fatty acids and lipogenic enzymes and causes a decrease in liver fatty acid synthesis and ultimately the lipid profile. However, more studies should be considered to evaluate other effects of replacing this vegetable oil.

Black seeds can affect the productive and physiological performance of birds and laboratory animals. This research aimed to study the effect of black seed levels on production and reproduction parameters in Japanese quail.

The experiment was conducted on 400 pieces of adult 12-week-old quails in 20 experimental units with four treatments and five replications for 6 weeks. Experimental treatments were control (without black seeds, feeding with a basic diet), a basic diet with 1% of black seeds, the basic diet with 2% of black seeds, and the basic diet with 3% of black seeds. At the end of the experimental period, blood was taken from one randomly selected male bird from each replicate for testosterone measurement, and they were killed to examine reproductive components. The produced quail eggs of each experimental replication were collected daily and their number was recorded and weighed separately every week. At the end of the test period, 30 quail eggs from each replication were collected for 4 days and placed in the egg combs. The selected quail eggs were arranged in the setter combs and incubated in an automatic incubator at 37.7 °C and 55% humidity. For 15 days of the setter stage, the temperature was 37.2°C and 70% humidity for 3 days of the hatcher stage. The number of chickens in each replication and their weight and losses were recorded after hatching. Reproductive parameters, including fertility rate, total hatch, and the hatch of fertile eggs, were examined at the end of the incubation period.

The reproductive components and male Japanese quail testosterone were not affected by different levels of black seed (p < 0.05). Mansour et al. (2003) showed that treated groups (olive oil, black seed oil, and pomegranate extract) slightly affected testosterone, LH, FSH, and Inhibin-B compared to the control group. Considering that black seed has many properties, it did not show an effect on testosterone levels in the treatments compared to the control treatment; however, it did not have a harmful effect on the hormone levels. Egg production was affected by experimental treatments (p < 0.05). Egg weight parameters were not affected by experimental treatments (p < 0.05). The highest percentage of egg production was recorded in the treatments with 2 and 3% of black seeds, and the lowest percentage of egg production belonged to the treatment with 1% of black seeds. Aydin et al. (2008) added black seeds to the diet of Leghorn laying hens of line strains and reported that black seeds at the levels of 2 and 3% positively affected egg production and shell quality and reduced cholesterol in the yolk. Hasankhah et al., (2021) investigated different black seed levels on the safety and performance of laying hens and reported that using 4% and 5% black seeds positively influenced egg production. Fertility and overall hatching were affected by experimental treatments (p < 0.05), but fertile eggs and the weight of hatched chicks were not affected by experimental treatments (p < 0.05). The highest and the lowest fertility and hatch belonged to the treatments with 2% and 1% of black seeds, respectively. Madrasi and Pournaji (2018) studies on the effect of black seed hydroalcoholic extract on female reproductive factors in small laboratory mice showed that this extract increased the follicle graph and corpus luteum, which could have a positive result in female fertility. Except for mid-embryonic losses, other embryonic parameters were not affected by experimental treatments (p < 0.05). Blood parameters were not affected by experimental treatments (p < 0.05). Taghiani et al. (2010) investigated the effect of black seeds (2 and 4 g/kg) in the basic diet of broiler chickens on blood parameters. Their results showed that serum biochemical parameters, including albumin, triglyceride, LDL, HDL, and total cholesterol, were not significantly affected by dietary treatments.

Based on the results of the present research, black seed can have an effect on fertility, hatchability, and egg production due to the presence of compounds such as thymoquinone, fatty acids, and piscimen, and resulting in better reproductive performance in mother quails. In general, the use of black seeds at a 2% level in the Japanese quail diet can positively affect fertility and egg production.

The aim of this research was to investigate the effect of different levels of dietary fat and vitamin E on the growth performance and blood parameters of Japanese quail. The experiment was conducted with 320 pieces of one-day-old quail in the form of a completely randomized design with 20 experimental units including 5 groups, 4 replications and A number of 16 pieces of quail chicks were performed in each repetition. The experimental groups include: 1) base diet (control), 2) base diet containing 2% soybean oil, 3) base diet containing 2% tallow oil, 4) base diet containing 2% soybean oil and 200 mg/kg vitamin E, 5) base diet They contained 2% tallow oil and 200 mg/kg vitamin E. The results showed that the treatment containing 2% tallow oil and vitamin E increased the weight of the birds compared to the control treatment (P<0.05). The lowest feed consumption and feed conversion ratio were observed in the birds that received the groups containing soybean oil or tallow along with vitamin E. Persistence percentage was not affected by experimental groups (P<0.05). The highest level of production index was related to the birds fed with the level of two percent tallow oil and E. The effect of experimental groups on blood parameters including total protein, albumin, glucose, cholesterol, triglyceride, LDL, HDL was not significant (P<0.05). In general, the use of two percent tallow oil along with vitamin E in the diet of birds improved the performance of quails.

Growth traits (such as body weights at different ages) in most of the birds have been often considered in most of the poultry breeding programs. Changes in growth pattern can be evaluated through measuring body weight traits at regular intervals and using mathematical functions (growth curve functions). For this purpose, data from 1182 wild (including 905 female and 277 male) and 674 Italian speckled (including 499 female and 175 male) quails were utilized. Accordingly, after body weight at hatch, body weights of the birds were recorded through 45 days in a 5-day interval manner. Gompertz, Logistic, Lopez, Richards, and von Bertalanffy were used to estimate growth curve parameters. To evaluate/ rank the goodness of fit for functions, the BIC, AIC, MSE, and  were used. Based on results, Richards’ function for both studied populations (wild and Italian speckled quails) and for both genders (females and males) were the best fitted model. The relatively same growth pattern and same function for describing growth pattern in these two quail strains refer to the same growth traits, therefore simultaneous production of them can be achieved under same management practices. Moreover, comparing results of the current studies with other researches, by comparing other studies with this study’s results, it can be concluded that increasing the number of records and shortening the weighing intervals can be effective in determining the appropriate function.

The aim of this investigation was to examine the alterations in the nucleotide sequence of CAPN2 and CAPN3 genes among a population consisting of nine Japanese quails. The study also aimed at determining the genetic diversity within these populations, as well as establishing their phylogeny relationship with other species. To achieve these goals, data on nucleotide sequences for both CAPN2 and CAPN3 were extracted from 62 different species available in World Gene Bank (NCBI), alongside that found for Japanese quail samples and analyzed using DnaSP software coupled with MEGA program techniques. The results showed that CAPN2 gene polymorphism was more than the CAPN3 gene in Japanese quail and as a result, the conserved regions in CAPN3 gene were more compared to the CAPN2 gene. The numerical value of dN/dS ratio for Japanese quail was estimated in the CAPN3 gene (0.94) and in the CAPN2 gene 0.68, which respectively indicate neutral selection and purifying selection on these two genes during evolution. The results of the neutral evolution test (Tajima's D) for CAPN2 and CAPN3 genes in all the discussed species were positive and more than one, which indicates positive selection for these genes in all the studied species. The findings of this investigation can aid in identifying the areas within CAPN2 and CAPN3 genes linked to distinct phenotypic traits seen in the examined species. Analysis of phylogeny revealed that these two genes have displayed varying evolutionary responses along different studied species,

Due to increasing in demand for quail products, including eggs and meat, and the cost-effectiveness of producing this product, quail breeding has found a special place in the poultry industry. Japanese quail is a diverse type of poultry that has unique characteristics such as delicious and nutritious meat and high egg production. In fact, high activity and movement in quails increases the storage of glycogen in their muscle tissues, which makes the meat of this bird very delicious, like that of hunting birds. The value of protein in the meat of this bird is 24.91%, while the rare amino acids that are not found in other proteins are abundantly found in the meat of this bird. The efficiency of converting feed into meat production of Japanese quail can play an essential role in the economy of raising this bird. Among the populations related to the Japanese race, the brown, white and gray populations are more widespread. However, there is not much documented information about the economic and functional characteristics of these and other Japanese quail populations in the country. This research was conducted in order to compare production performance, carcass characteristics, and egg laying characteristics and hatching percentage of three varieties of white, gray and brown Japanese quail.

This experiment was conducted with 3 treatments and 4 replicates and a total of 360 Japanese quail up to 42 days of age, with the same rearing conditions and diet in a completely randomized design. During the experiment performance parameters were recorded. Experimental treatments include white population of Japanese quail, brown population of Japanese quail and gray population of Japanese quail. At the end of the test period (42 days), 3 quail that were close to the average weight of the flock were selected from each repetition. After slaughtering, the characteristics of the carcass (carcass, breast and thigh) were measured. Then, after the start of laying, 144 Japanese quails (with the ratio of 3 to 1 female to male) were reared in cages to measure the egg characteristics, and the hatchability percentage. After the birds reached the laying age, 3 eggs were selected from each experimental unit and the quality characteristics of the eggs such as average egg weight, egg mass, specific gravity, Haw unit and egg shell thickness were measured. Also, to measure and calculate the percentage of hatching, 24 eggs were selected from each replication, and then the eggs with unfavorable appearance characteristics such as (bad shape, calcium shell, too big and too small eggs, green shell, etc.) were removed, then they were disinfected with formaldehyde gas, and then they were transferred to special combs for eggs. The quail eggs were transferred into the incubator. After transferring the eggs to the incubator, on the 14th day of incubation, the eggs were transferred from the setter to the hatcher, and on the 17th and 18th days of incubation, the newly hatched chicks were removed and the percentage of chicks hatched of each treatment was calculated.

The results of the experiment showed that the experimental treatments had no significant effect on the amount of feed consumption and feed conversion ratio in different periods, but had a significant effect on the daily weight gain in the final periods and the entire breeding period (p<0.05), so that white quail had the highest average weight gain. Also, the results showed that the experimental treatments were significant on the efficiency of carcass percentage in different varieties, so that the white strain has the highest carcass percentage (p<0.05), but different strains had a significant effect on other characteristics. There were no carcasses. The results showed that there was a significant difference between different varieties of Japanese quail on white height, shell weight, haw unit and mass weight in weeks 16 to 17 (p<0.05). So that the highest amount of Haw unit and white height is related to the brown strain and the lowest is related to the gray strain, the white variety had a higher mass weight than other varieties, and also the highest amount of shell weight is related to the gray variety and the lowest It is related to brown treatment. On the other hand, there was no significant difference in the percentage of hatchlings between different Japanese quail populations.

The results of the present experiment showed that there was a significant difference between different varieties of Japanese quail in different traits, so that the white variety of Japanese quail has the highest weight gain and also has a better carcass percentage than the gray and brown varieties. On the other hand, the white variety of Japanese quail showed the highest quality in egg quality, including egg unit and mass weight. Therefore, it can be concluded that in this experiment, the white variety of Japanese quail showed better and more suitable conditions than the brown and gray varieties of Japanese quail in terms of growth performance and egg quality traits.

Japanese quail has a rapid growth rate (3 to 4 generations per year) and is relatively resistant to many diseases. Due to its high productivity, it has gained importance as an animal model in biological and genetic studies worldwide. Nutrition is a key factor that affects production efficiency in quails. Japanese quails require a diet that contains high-quality protein and a balanced profile of amino acids. Branched-chain amino acids (leucine, isoleucine, and valine) not only contribute to protein synthesis but also play a role in other metabolic activities. Among the branched-chain amino acids, valine is a limiting amino acid in corn-soy-based diets. Protein is the most expensive component of the diet and has a significant impact on production costs in poultry. Nowadays, reducing the protein level in the diet has garnered attention for cost reduction in farming and for mitigating environmental pollution resulting from ammonia emissions and nitrogen excretion in the poultry industry. However, reducing the protein level in the feed without proper supplementation of amino acids can lead to decreased feed intake, reduced production levels, and changes in social behavior in birds. Published reports indicate that adding crystalline amino acids to low-protein diets in meat birds can have similar performance to high-protein diets at different growth stages. In most cases, valine becomes limiting with reduced protein levels in the diet. Considering the important metabolic roles of branched-chain amino acids, especially valine, in rapidly growing birds, the aim of this experiment was to investigate the effects of using diets containing different digestible valine levels on the performance, growth traits, and histology of the liver and magnum in Japanese quails during the growth period.

All experimental procedures for the care and use of animals in the present study were approved by the animal care committee of the University of Tehran. Thousand one-day-old quails were given 5 dietary treatments, such that each treatment was replicated 5 times and 40 birds per replicate in a completely randomized design, during 1–42 days of age. Experimental diets were formulated to meet nutrients recommendation of growing quails with different levels of dietary digestible valine concentration (0.75, 0.85, 0.95, 1.05 and 1.15 %) in diets with a low protein (17.7-17% protein). The experimental diets provided 2,9 kcal metabolizable energy per gram. Other nutrients were provided based on the recommended nutritional requirements for growing quails. Other nutrients were formulated based on the recommended nutritional requirements for growing quails. The experimental diets were adjusted for two age periods: 1-21 days and 22-42 days. The birds received 24 hours of light until three days of age, followed by 23 hours of light and one hour of darkness daily. The parameters investigated in this experiment included growth performance, feed consumption, conversion ratio and carcass performance. The bird weights were measured at the beginning of the experiment and on days 21 and 42. Feed consumption on days 21 and 42 was calculated based on the difference between the amount of feed provided and the remaining feed. The weight of dead birds was used to correct the amount of feed consumption. On day 42, one male quail and one female quail were randomly selected from each replicate and killed after 6 hours of starvation. Additionally, after sampling the liver and magnum tissues, their histomorphological characteristics (nuclear diameter of hepatocytes, diameter of sinusoids in the liver tissue; epithelial height, inner muscle thickness, outer muscle thickness, gland diameter, and gland depth in the magnum tissue) were investigated.

During the breeding period, the quails that received the diet containing 0.95% and 1.05% digestible valine had higher body weight gain (BWG) and feed conversion ratio (FCR), respectively. Feed intake (FI) and mortality were not affected by the treatments. Dietary treatments did not have any significant effect on the carcass characteristics (both male and female). However, the carcass yield was higher in male quails and the relative weight of breast and intestines was higher in female quails. In the treatments containing 1.05% and 1.15% of valine, the diameter of Liver cell nucleus and the diameter of liver hepatocytes were the highest, which indicates liver damage. The volume of sinusoids in female birds increased with increasing valine levels in the diet; So that in birds that received diets containing levels higher than 0.95% valine was more than birds fed with rations containing 0.75% valine. Based on the results of this study, different levels of valine in diets containing 17% crude protein had a significant effect on the histology of the magnum tissue (epithelial height, inner muscle thickness, outer muscle thickness, gland diameter), although only the depth of the glands showed a tendency for significance with 0.85% valine.

Based on the results, increasing the level of digestible valine in low protein diets up to 0.95% improves growth performance and feed conversion ratio in growing quails. However, it seems that the use of high levels of digestible valine in low protein diets (more than 0.85%) may lead to tissue damage in the liver and have a negative effect on growth performance. Further studies are recommended in this field.

This study was carried out to investigate the effects of probiotics (lacto-feed) and stevia leaf powder as phytogenic compound in the diet on performance, carcass characteristics, intestinal microbial population and some blood parameters in Japanese quail.

This experiment conducted as a completely randomized design with 320 Japanese quail chicks and mixture of both sexes (average weight 7-9 g), in four treatments, four replications and 20 chickens per replicate. Experimental treatments included: 1- Diet without additives (control), 2- Diet containing probiotic lactofeed (0.02% up to 21 days and 0.01% up to 42 days) 3- Diet containing 1% stevia leaf powder and 4- Diet containing 2% were stevia leaf powder. The effects of probiotic lacto-feed and stevia leaf powder as phytogenic compound in the diet on yield, carcass characteristics, intestinal microbial population and some blood parameters of Japanese quail.

The results showed that experimental treatments; there was a significant in weight gain and feed conversion ratio between the experimental treatments (p<0.05), which the treatments containing stevia leaf powder had the highest weight gain and the lowest feed conversion ratio, and the difference increased with increasing the percentage of stevia leaf powder (p<0.05). Carcass weight in treatments containing stevia and lacto-feed was significantly higher than the control treatment (p<0.05). Also, the addition of lacto-feed probiotics and stevia leaf powder caused a significant increase in thigh percentage tin compared to the control group (p<0.05). The control treatment had the highest (1.21%) and the lactofeed treatment had the lowest (0.38%) abdominal fat percentage (p<0.05). The highest of triglyceride and VLDL concentrations was observed in the treatment containing probiotic lacto-feed (p<0.05). Also, the treatments containing Stevia leaves powder had higher triglyceride concentration than the control treatment (p<0.05). Blood glucose was significantly higher in the treatment containing probiotic lactofid and in the treatments containing stevia leaf powder was lower tin compared to the control treatment (p<0.05). The effect of experimental treatments on the total population of Aerobic microbes and Coliform was not significant, while the population of Lactobacillus in treatments containing stevia leaf powder was significantly higher than the control treatment (p<0.05).

It can be concluded that the use of stevia leaf powder as a phytogenic compound in the diet improved performance and carcass characteristics of Japanese quail chicks.

Isoflavones or also known as phytoestrogens are naturally synthesized phenolic components of plants that have either estrogenic or antiestrogenic effects. A variety of phytoestrogens have been shown to bind to both isoforms of the estrogen receptor (ERα and ERβ) in vitro and activate ER-dependent gene transcription. There are 3 main classes of phytoestrogens: (1) isoflavones [derived principally from soybean, i.e. soybean isoflavone (SIF)]; (2) lignans (found in large quantities in flaxseed), and (3) coumestans (derived from sprouting plants like alfalfa). SIFs are the most effective bioactive group due to the high consumption of soy food in humans and animals. Considering the literature data, it must be ascertained that the most biologically active and the best described isoflavoneis genistein. Recently, the interest in genistein action has grown because of its role as a factor which can modulate processes involved in carbohydrate and lipid metabolism. These changes are often accompanied by alterations in the hormonal status of the organism. Isoflavones has gained popularity due to positive effects in human health as an alternative therapy for menopausal symptoms, osteoporosis and some hormonal disorders. On the other hand, these compounds may be considered endocrine disruptors due to negative effects found in the reproduction of animal models. It was reported that soy isoflavones antagonize estrogen-induced behavior in the brain. Moreover reproduction in the birds can be negatively influenced by dietary isoflavones. In birds, isoflavones and other phytochemicals may, in part, regulate seasonal reproductive cycles through inhibition of reproductive behavior. In general, the effects of isoflavones on poultry reproduction are contradictory. Few studies have been conducted on the effects of phytoestrogens in the diet on the reproductive performance of birds. Isoflavones and other phytochemicals may partially regulate the seasonal reproductive cycles of birds by inhibiting reproductive behavior. Therefore, in the present study, the effects of dietary supplementation of soy isoflavones on the performance, sexual behavior and plasma levels of some body hormones were investigated in male Japanese quail.

A total of 80 male Japanese quail were purchased at 28 d and randomly divided into four treatment groups with four repetition of 5 quails each, according to a complete randomized design. The birds after one week of gradual adaptation to new rearing system and feed, received the same basal diet with soy isoflavones added at 0 (control), 0.36, 0.72 and 1.08 g/kg feed. Soyagol tablets produced by Goldaru pharmaceutical company were used as a source of genistein. At 52 days of age, six birds per treatment were selected for blood collection and plasma levels of testosterone and T3 hormone were determined by commercial kits. At the end of the feeding trial (56 days of age), 6 birds from each group were slaughtered in order to make measurements of carcass cuts yield and some internal organs. Feed consumption, weight gain and feed conversion efficiency were calculated weekly during three experimental period. During the last week of the trial, appetitive male sexual behavior was assessed by measuring a learned social proximity response and consummatory behavior was assessed by measuring copulatory behavior per se. The size of the cloacal glands was also recorded at the beginning and end of the experiment using a digital Vernier caliper. This research was design using a complete randomized design. The data were analyzed using the GLM procedure of SAS software (SAS Institute, 1999). Where treatment effects were found (P≤ 0.05), means were separated by Duncan's multiple range tests.

The results showed that feeding soybean isoflavones at the level of 1.09 g/kg diet, significantly decreased the body weight gain of male quails during the second and third weeks of feeding trial compared to the control group (P<0.01). Moreover, the high level of isoflavone also revealed decreased feed intake during the second week of the supplementation (P<0.01). Effects of 3 week of soy isoflavones (ISF) treatment in the diet of Japanese quails were not statistically significant on body weight gain and feed conversion ratio. The experimental treatments had no significant effect on the relative weight of heart, liver and carcass yield. There was no mortality during the trial period. The inclusion of soy isoflavones at 1.08 g/kg diet, significantly diminished plasma testosterone and increased plasma T3 levels compared to the control (P<0.01). In the same dosage, the frequency of appetitive and consummatory aspects of sexual behaviors was also reduced compared to the control group (P<0.01). Increasing the dose of isoflavone compounds in the diet of male quails also exhibited decreasing the somatic testicular index and the size of the cloacal gland in a dose-dependent manner (P<0.01).

It is concluded that soy isoflavone may induce an inhibitory effect on male sexual behavior in Japanese quail by acting as an endocrine disruptor and inhibiting reproductive development. Soy isoflavones in doses of 0.36 and 0.72 g/kg diet, despite the fact that they were much higher than the usual doses used in previous studies, did not significantly affect the body weight gain and relative weights of the liver in Japanese quail. Therefore, it can be concluded that isoflavones did not show severe toxic and hormone-disrupter effects at these supplementation levels. However, isoflavones in the high dose used in the present study decreased significantly plasma testosterone concentrations and led to dramatic changes in the testes weights and sexual behavior of male Japanese quails. The present results suggest that high concentrations of isoflavones in the diet may exert endocrine disruptor-like effects on the reproductive system of the male, but not the female, quail.

Identifying genes with large effects on economically important traits, has been one of the important goals in sheep breeding. A method to identify new loci and confirm existing quantitative trait loci (QTL) is through genome-wide association studies (GWAS). QTL-assisted selection and genomic regions affecting the production traits have been considered to increase the efficiency of selection and improve production performance. GWAS typically focuses on genetic markers with the strongest evidence of association. However, single markers often explain only a small component of the genetic variance and hence offer a limited understanding of the trait under study. A solution to tackle the aforementioned problems, and deepen the understanding of the genetic background of complex traits, is to move up the analysis from the single nucleotide polymorphism (SNP) to the gene and gene-set levels. In a gene-set analysis, a group of related genes that harbor significant SNP previously identified in GWAS is tested for over-representation in a specific pathway. The present study aimed to conduct a GWAS based on gene-set enrichment analysis for identifying the loci associated with economic traits using the high-density SNPs.

In this research, to identify genes and biological pathways associated with some economic traits, GWAS based on gene-set enrichment analysis was conducted in a F2 population derived from a reciprocal cross by using Illumina iSelect 4K Japanese quail SNP Bead chip. For each bird, traits including body weight gain, feed intake, feed conversion ratio, tibia ash, and foot ash were measured. The SNPs that were associated with traits were identified based on mixed linear models using GCTA software and no correction was made to adjust the error rate. The gene-set analysis consisted of three different steps: (1) the assignment of SNPs to genes, (2) the assignment of genes to functional categories, and (3) the association analysis between each functional category and the phenotype of interest. In brief, for each trait, nominal P<0.005 from the GWAS analyses were used to identify significant SNPs. Using the biomaRt R package, the SNPs were assigned to genes if they were within the genomic sequence of the gene or a flanking region of 15 kb up- and downstream of the gene, to include SNP located in regulatory regions. For the assignment of the genes to functional categories, the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway databases were used. The GO database designates biological descriptors to genes based on attributes of their encoded products and it is further partitioned into three components: biological process, molecular function, and cellular component. The KEGG pathway database contains metabolic and regulatory pathways, representing the actual knowledge of molecular interactions and reaction networks. Finally, a Fisher’s exact test was performed to test for overrepresentation of the significant genes for each gene set. The gene enrichment analysis was performed with the goseq R package. In the next step, bioinformatics analysis was implemented to identify the biological pathways performed in BioMart, Panther, DAVID, and GeneCards databases.

Gene-set enrichment analysis has proven to be a great complement to GWAS. Among available gene set databases, GO is probably the most popular, whereas KEGG is a relatively new tool that is gaining ground in livestock genomics. We hypothesized that the use of gene-set information could improve prediction. It is likely that a better understanding of the biology underlying meat production specifically, plus an advance in the annotation of the quail genome, can provide new opportunities for predicting production using gene-set information. 11 SNPs on chromosomes 2, 3, 4, 5, 10, 18, 20, 24, and 27 located in NPY, DRD2, PTPRN2, BMPR1B, MYF5, IGF2BP1, MYO1E, FGF2, LDB2, BMP4, ACOX1, PCK1, PLCB4, PLCB, and PLCG1 genes were identified. According to gene-set enrichment analysis, 23 categories from gene ontology and the KEGG pathway were associated with the traits (P˂0.05). Among those categories, Protein glycosylation, Myoblast differentiation, Positive regulation of muscle cell differentiation and Biological MAPK signaling pathway, and Calcium signaling pathway have a significant association with skeletal muscle fiber, feed intake, and availability utilization.

This study supported previous results from GWAS and revealed additional regions associated with these economically important traits. Using the findings of this study could potentially be useful for genetic selection to improve production in Japanese quail.

Quails are beneficial for their meat and eggs and have been the focus of poultry breeders in recent decades. Egg quality traits are usually divided into external (such as shell quality and egg weight) and internal (like yolk and albumen parameters) traits. Shell characteristics are important factors to determine egg quality. The breakage of quail eggs can be occurred in various processes such as collection, packaging, and transportation or in the setter and hatcher devices, and leads to serious economic problems for the breeders in the poultry industry. The size and weight of the quail egg are important factors in the marketability of this product. From an economic point of view, the yolk is the most valuable part of the egg. The yolk is a concentrated source of nutrients, as well as it has a significant effect on the weight of the chicken. The ratio of yolk to white in quail eggs has been reported to be 35 to 65, which is higher in comparison to laying hens. Egg quality can be affected by different factors such as genotype, breed, strain, age, management, nutrition, temperature, and illness. Although there have been many studies to determine the environmental factors on traits related to egg quality in quail, there are few studies to investigate the effect of genetic factors and different mating systems on the occurrence of these traits. Therefore, the present study was conducted to estimate genetic parameters of external and internal egg quality traits in wild and white strains of Japanese quails.

A total number of 570 laying quails were obtained from pure and cross-mating groups of wild and white Japanese quails. The base population was divided into four mating groups including two pure and two crossed mating groups (group 1: wild male × wild female; group 2: white male × wild female; group 3: wild male × white female, and group 4: white male × white female). The studied traits included external (egg weight, length, and width, shell weight and thickness, and egg shape index) and internal (yolk weight, albumen weight, yolk index, albumen index, and internal egg quality unit) egg quality traits. The effects of hatch and mating groups on traits related to egg quality were investigated. The means of traits related to external and internal egg quality were compared using the Duncan test. (Co)Variance components and genetic parameters of traits related to external and internal quality traits were estimated by multiple trait animal models and restricted maximum likelihood using ASREML software.

The effect of the hatch on egg weight, shell weight, and albumen weight was significant (P<0.05) and the eggs from the second and third hatches showed higher egg weight, shell weight, and albumen weight in comparison to the first hatch (P<0.05). The difference between mating groups was not significant (P>0.05) except for albumen and egg weights. The laying quails from the pure white mating group showed lower albumen and egg weights (P<0.05). The heritability estimates for traits related to external egg quality varied from 0.16 (egg shape index) to 0.39 (egg weight). These estimates for traits related to internal egg quality ranged from 0.10 (internal quality unit) to 0.31 (yolk weight). Genetic correlations were estimated from -0.33 (between egg length and egg shape index) to 0.71 (between egg length and width) for traits related to external egg quality, and from -0.37 (between yolk weight and yolk index) to 0.71 (between albumen weight and albumen height) for traits related to internal egg quality, respectively. Phenotypic correlations varied from -0.32 (between egg length and egg shape index) to 0.61 (between egg length and width) for traits related to external egg quality, and from 0.11 (between yolk index and albumen height) to 0.59 (between the internal quality unit and albumen height) for traits related to internal egg quality, respectively.

Heritability estimates for traits related to egg quality were moderate which indicates the significant effect of additive genes on the occurrence of these traits. Positive genetic correlations between egg weight and traits related to external egg quality, as well as appropriate genetic correlations between traits related to internal egg quality showed that selection based on some egg traits like egg weight and internal egg unit can effectively lead to the improvement of other egg quality traits.

The growth models own a very great importance in biological systems.  For example, by analyzing the growth curve of ruminant animals and poultries, it is possible to fastener and to manage their rearing, nutritional and behavioral requirements, based on their growth routines and principles. On the other hand the growth pattern of animals might be used in evaluating their genetic potential for breeding purposes. Thus, to evaluate and describe the growth pattern of Japanese quail, this study aimed to evaluate the capabilities and advantages of non-linear and nonlinear mixed models to describe and evaluate the growth pattern of Japanese quail.

In order to assess and designate the growth pattern of Japanese quail, we used the growth data of three groups; high weight (HW), low weight (LW) and the control lines of Japanese quail. Different models, including logistic, Gompertz and Richard's both non-linear and nonlinear mixed models were fitted to the data. For evaluation of models three criteria including coefficient of determination (R2), mean square error (MSE) and Akaike's information criterion (AIC) were employed as criteria to compare the mentioned six different models.

Values of the coefficient of determination (R2), for logistic, Gompertz and Richard's nonlinear models were 0.954, 0.957 and 0.951, mean square error (MSE) for three models were 74.034, 72.560 and 72.730, and Akaike's information criterion (AIC) for the models were 65829, 65307 and 65349, respectively. The results for non-linear mixed models, in the same order mentioned above and for R2, MSE and AIC, were 0.976, 0.978 and 0.978; 33.400, 31.658 and 31.849; 61449, 60641 and 60591 respectively.

The results showed that nonlinear mixed models had higher accuracy and less mean square error, compared to nonlinear models and Richard’s model is more capable (better) to the predict growth pattern of Japanese quail. Also among non-linear models Gompertz model had a better fit to the purpose. In general it can be said that the parameters determined by the functions inspected in this study, are not much different.

Based on the recommendations of some poultry nutrition references as National Research Council (NRC 1994), growth period of growing Japanese quails have been considered to be six weeks and only one dietary protein concentration was recommended for the entire growth period. However, the amino acid requirements of growing quails are similar to those of broilers as the percentage of the diet decreases with age, and applying one level of protein throughout the rearing period may cause deficiency or loss of amino acids compared with daily requirements. Given the high cost of protein in quail diets and the fact that few researches has been done on the effect of dietary protein levels at different phases of growth period on quail performance, this experiment was conducted to investigate different dietary regimens of protein on production and economic performances and also carcass characteristics of Japanese quails.

The experiment was carried out in a 3×3 factorial arrangement (3 protein levels: low (L)=20%, medium (M)=22% and  high (H)=24 percent in grower phase (8-21 days)× the same dietary protein levels, in finisher phase (22-42days)) with 9 treatments, 5 replicates and 8 pieces of quails per each replication. All chicks were received the same starter diet with 2900 kcal/kg Metabolizable energy and 24% crude protein (CP) from time of hatch up to 7 days of age and after that they were received dietary L×L, L×M, L×H, M×L, M×M, M×H, H×L, H×M and H×H protein programs. Production traits such as feed consumption, body weight gain, feed conversion ratio and production index at the whole growth period, as well as some economic traits such as feed cost per gain monetary returns per quail and also some traits related to carcass characteristics and meat quality such as edible carcass percentage, water holding capacity and oxidative spoilage index of meat were measured or calculated.

During 8-42 days of age, different dietary protein levels in growing phase had no significant effect on feed intake, weight gain and feed conversion ratio (FCR). While, higher protein levels (22 and 24%) in finishing phase significantly resulted in a better weight gain, FCR and production index of quails. Protein levels in grower and finisher phases had no significant effect on monetary returns however, increase in dietary protein level in finishing phase resulted in a significant feed cost to the gain at 8-42 days. Different dietary protein programs had no significant effect on carcass part percentages, water holding capacity and oxidative rancidity of meat.

For proper performance and economic production of quails protein regimen with at least 20% protein in grower and 22% protein in finisher phases could be recommended.

The aim of the present study was to evaluate the genetic architecture, genomic regions and candidate genes associated with body weight gain, feed intake and feed conversion ratio in Japanese quails. For detection the informative genomic windows, genotyping data on 920 quails was used in a single-step genome-wide association study. The BLUPf90 family software was used to perform related analyses. Theresults was calculated based on the proportion of additive genetic variance (agv) explained by genomic region with an average size of 1.5-Mb of adjacent SNPs. Windows with accounting for more than 1% of the agv were used to identify genomic regions and to search for candidate genes. A total of 13 significant windows over 8 chromosomes were explained 23% of the agv for the body weight gain and including SMYD1, ADGRG6 and CFL2 candidate genes. A peak on CJA2 explained the largest proportion of variance. For feed intake, we identified 20 informative windows across 8 chromosomes and including ACSL, PPA2, FGF2 and RBL2 candidate genes. These regions explained 38% of the agv and a peak on CJA4 explained of agv. Also, for the feed conversion ratio, 12 significant windows were identified on 7 chromosomes and explained 23.7% of agv, contained ATRNL1 and PTPN4 candidate genes. Four genomic regions had a pleiotropic effect. Considering the identification of new genome regions and the key role of the mentioned genes related to feed intake, the single step method can be validated for GWAS in feed efficiency traits.

An experiment was conducted to evaluate the effect of particle size and feed form on growth performance, digestibility, and intestinal morphology of growing Japanese quails from 21 to 35 days of age. A total of 480 mixed Japanese quails were used in a completely randomized design with a 2×3 factorial arrangement, three feed forms (mash, crumble, and pellet) and two levels of particle size (fine, and coarse), with 6 experimental treatments, 4 replicates and 20 birds per each replicate. Birds consumed pelleted and crumbled feeds with coarse particle size showed significantly higher body weight gain, compared to the birds fed with mash feed with both coarse and fine grinding particle size(p<0.05). A significant increase in feed intake were detected in birds fed with pelleted form (p<0.01). Feed conversion ratio was significantly higher in quails fed with pelleted diets than mash and crumbled diets and also in fine particle size than coarse particles (p<0.01). Birds fed with pellets with higher particle size had significantly heavier gizzards (p<0.05). The length of villi was significantly higher in birds fed with pelleted and crumbled feeds (p<0.01). The highest percentage of dry matter and nitrogen digestibility were observed in birds fed with the mash form diet and also in coarse particle size diets (p<0.05). Based on the results, the use of crumbled diets with coarse particle size are recommended due to more weight gain compared to the mash diets and also better feed efficiency in compare to the pelleted diets.

Application of antibiotics causes two major health problems, including antibiotic residues in body tissues and animal products and the resistance of pathogens to antibiotics. On the other hand, antibiotics improve growth, feed efficiency and control infectious diseases. Following the ban on the use of antibiotics as growth stimulants in the poultry industry, the EU has been paying more attention to non-antibiotic growth-promoting compounds since 2006, including organic acids, probiotics and herbs. Previous studies have shown that in many oils of dark plants Mentha pipperita, thymol, carvacrol, menthol and in some cases paracetamol are the most important components of growth improvement, their antimicrobial and antioxidant properties. kefir is also a natural probiotic. The fermenting agent of kefir milk is kefir seeds, which contain casein and the species Lactobacillus, Saccharomyces, Streptococcus and others. Diets containing Mentha pipperita, by improving the microflora of the gastrointestinal tract and reducing the population of harmful microbes, can create better conditions for the use of final feed products and thus improve the growth and better performance of chickens. In studies, the positive effects of kefir on the performance and biochemical parameters of broiler blood have been reported.

This study was conducted in the animal husbandry research station of Khuzestan University of Agriculture and Natural Resources. In this study, four hundred one-day-old Japanese quails were used in a completely randomized design with four treatments, four replications and 25 observations per replication for 35 days. The experiment was performed. Treatments are: Treatment 1) Basic diet + drinking water (control group), Treatment 2) Basic diet + drinking water + 0.5% Mentha pipperita extract, Treatment 3) Basic diet + drinking water + kefir milk 2%, Treatment 4) Basic diet + drinking water + Mentha pipperita extract 0.5% + kefir milk are 2%. The weight of quails was measured at the end of each week and the feed consumed was determined. The average of daily weight gain, feed intake and feed conversion ratio were calculated. At the end of the fifth week, from each replicate, two quails with a weight close to the average were selected and slaughtered.  Breast and thigh meat samples were used to measure pH, water holding capacity and meat moisture content. Also, at the end of the fifth week, two samples were randomly selected from each replicate and blood was taken from their wing vein to measure blood parameters, thyroid hormones and testosterone.

The addition of mint and kefir extract significantly increased the weight of Japanese quails. The highest weight gain in the third and fourth weeks was observed in treatments 2, 3 and 4, respectively. In a study that investigated the effect of kefir on broiler performance, it was shown that the use of kefir as a natural probiotic causes significant weight gain, which is consistent with the present results. Mentha pipperita essential oil and kefir have been reported to improve feed conversion ratio and stimulate digestion in broilers. Kefir added to broiler drinking water has been reported to increase body weight, increase daily weight, reduce daily feed intake and feed conversion ratio, and improve performance. Mentha pipperita lowers blood cholesterol levels by liver or intestinal cells. Peppermint also accelerates LDL catabolism by increasing liver LDL receptors. In addition, Mentha pipperita inhibits the activity of the enzyme fatty acid synthase (FAS) and increases the beta oxidation of fatty acids, thereby effectively reducing fat storage. The concentration of thyroid hormones was not affected by the treatments. In some studies, thyroid hormone concentrations increase with nutrition of mint and kefir. Testosterone concentrations were significantly affected by experimental treatments. Changes in the hypothalamic-pituitary-gonadal axis are the most important factors affecting the reproductive system. So far, the effect of many different plant extracts on the hypothalamic-pituitary-gonadal hormonal axis has been investigated. Plant extracts such as marjoram and ginger have been reported to increase testosterone, LH and sometimes FSH, and play an effective role in activating the hypothalamic-pituitary-gonadal axis. Peppermint, with its special chemical composition, can stimulate the signaling pathways of sex steroid production in the hypothalamic-pituitary-gonadal axis. The effect of experimental treatments on pH and moisture of breast and thigh meat and their water holding capacity was not significant.

According to this study and economic considerations, it seems that the combined use of 2% kefir and 0.5% Mentha pipperita in drinking water can improve the performance and also modulate lipid profiles in Japanese quails, as well as increase reproductive performance in males.

This study was done to investigate the effect of different levels of garlic powder on performance, relative weight of carcass components and blood metabolites of Japanese quail. One hundred 21-day male Japanese quails were randomly assigned to 5 treatments, 4 replicates and 5 birds in each replicate. The experimental treatment included: control diet without garlic powder, diets supplemented by 0.5%, 1%, 1.5% and 2% garlic powder. Quails fed for 21 days. Quails access to water and feed freely. Results showed that feed intake, daily weight gain and feed conversion ratio of quails were not affected by different levels of garlic powder. The effect of adding garlic powder to the diet on carcass efficiency, ventricular fat, total cholesterol and low-density-lipoproteins was significant (p <0.05). The birds fed diets containing 1% garlic powder had the highest carcass efficiency and the difference with birds fed diets without herbal medicine supplementation was significant (P <0.05). As increased garlic powder level in the diet, the blood total cholesterol and lipoproteins linearly decreased. According to the results obtained from this experiment, dietary supplementation by 1% garlic powder has a positive effect on carcass efficiency and decline undesirable blood metabolites.