Higher Egg Production Research Articles

Transcriptome comparative analysis of ovarian follicles reveals the key genes and signaling pathways implicated in hen egg production

BackgroundOvarian follicle development plays an important role in determination of poultry egg production. The follicles at the various developmental stages possess their own distinct molecular genetic characteristics and have different biological roles in chicken ovary development and function. In the each stage, several genes of follicle-specific expression and biological pathways are involved in the vary-sized follicular development and physiological events. Identification of the pivotal genes and signaling pathways that control the follicular development is helpful for understanding their exact regulatory functions and molecular mechanisms underlying egg-laying traits of laying hens.ResultsThe comparative mRNA transcriptomic analysis of ovarian follicles at three key developmental stages including slow growing white follicles (GWF), small yellow follicles (SYF) of recruitment into the hierarchy, and differentiated large yellow follicles (LYF), was accomplished in the layers with lower and higher egg production. Totally, 137, 447, and 229 of up-regulated differentially expressed genes (DEGs), and 99, 97, and 157 of down-regulated DEGs in the GWF, SYF and LYF follicles, including VIPR1, VIPR2, ADRB2, and HSD17B1 were identified, respectively. Moreover, NDUFAB1 and GABRA1 genes, two most promising candidates potentially associated with egg-laying performance were screened out from the 13 co-expressed DEGs in the GWF, SYF and LYF samples. We further investigated the biological effects of NDUFAB1 and GABRA1 on ovarian follicular development and found that NDUFAB1 promotes follicle development by stimulating granulosa cell (GC) proliferation and decreasing cell apoptosis, increases the expression of CCND1 and BCL-2 but attenuates the expression of caspase-3, and facilitates steroidogenesis by enhancing the expression of STAR and CYP11A1. In contrast, GABRA1 inhibits GC proliferation and stimulates cell apoptosis, decreases the expression of CCND1, BCL-2, STAR, and CYP11A1 but elevates the expression of caspase-3. Furthermore, the three crucial signaling pathways such as PPAR signaling pathway, cAMP signaling pathway and neuroactive ligand-receptor interaction were significantly enriched, which may play essential roles in ovarian follicle growth, differentiation, follicle selection, and maturation.ConclusionsThe current study provided new molecular data for insight into the regulatory mechanism underlying ovarian follicle development associated with egg production in chicken.

Non-linear prediction model for egg production of quails the tropics with methionine supplementation

This study aimed to predict the egg production of quails receiving methionine supplementation. Two hundred and four quails were divided into two treatment diets, and six replicates with 17 quails each. The treatment diets were control (P0) and 0.12% methionine supplementation (P1). Egg production data were collected for eleven weeks, and a T-test was performed. Next, the data was plotted to get the actual egg production curve. We used a logistic regression model to predict the egg production pattern and calculated the model’s fitness with the coefficient of determination (R2). The results showed that methionine supplementation increased egg production by 9.43% (p<0.01). Based on the actual production curve, the increase in initial production to peak production of P1 was slower than P0, but P1 had a higher egg production than P0. The logistic model predicts that peak production of P1 was higher than P0 (62.74% vs. 56.79%), although the production rate of P1 was lower than P0 (0.21 vs. 0.36). In addition, the accuracy of both P0 and P1 models was 0.88 and 0.92, respectively. Thus, the logistic model can predict quail egg production in the tropics due to diet modification with high accuracy.

Perches as Cooling Devices for Reducing Heat Stress in Caged Laying Hens: A Review.

Simple SummaryHigh ambient temperature is a critical environmental challenge to the egg industry worldwide. Laying hens that are under heat stress are unable to maintain a balance between body heat production and heat loss, leading to hyperthermia, which substantially disturbs physiological homeostasis and consequently reduces all parameters of production performance, e.g., egg production, egg quality, feed intake, feed efficiency rate, and longevity—ultimately causing substantial economic losses. To alleviate these deleterious effects, the egg industry and poultry scientists are working towards developing cooling methods to prevent heat stress. This review summarizes our recent discoveries that perches can be used as cooling devices to avoid or reduce heat stress detrimental effects on hen production, health, and welfare. Our results provide a novel strategy: perches, one key furnishment in cage-free and enriched colony facilities of modern laying hens, could be modified as cooling devices to improve hen thermal comfort during hot seasons.Heat stress is one of the most detrimental environmental challenges affecting the biological process and the related production performance of farm animals, especially in poultry. Commercial laying hens have been bred (selected) for high egg production, resulting in increased sensitivity to heat stress due to breeding-linked metabolic heat production. In addition, laying hens are prone to heat stress due to their inadequate species-specific cooling mechanisms resulting in low heat tolerance. In addition, hens have no sweat glands and feathering covers almost their entire body to minimize body heat loss. The poultry industry and scientists are developing cooling methods to prevent or reduce heat stress-caused damage to chicken health, welfare, and economic losses. We have designed and tested a cooling system using perches, in which chilled water (10 °C) circulates through a conventional perch passing through the layer cages to offer the cooling potential to improve hen health, welfare, and performance during acute and chronic periods of heat stress (35 °C). This review summarizes the outcomes of a multi-year study using the designed cooled perch system. The results indicate that conducting heat from perching hens directly onto the cooled perch system efficiently reduces heat stress and related damage in laying hens. It provides a novel strategy: perches, one key furnishment in cage-free and enriched colony facilities, could be modified as cooling devices to improve thermal comfort for hens during hot seasons, especially in the tropical and subtropical regions.

Correlation of Royal Jelly Composition with Swarming Tendency in Honey Bees (Apis mellifera): A Review

Honey bees are eusocial insects which respond to warm weather, abundant food source by increasing their population through swarming to ensure the survival of the colony. To maintain a superior colony a queen must have a nutrient-rich diet and high egg production. Royal jelly is a high-quality food which has numerous beneficial properties required for proper growth, development, survival of the queen. Factors like congestion, lack of adequate queen pheromone, abnormal queen pheromone, pathogenic infections, exposure to pesticides influence the queen quality which further promotes non-reproductive swarming behaviour. Worker bees analyse the queen condition to prepare for supersedure or emergency queen rearing. This review paper highlights the influence of royal jelly composition on the queen quality, the impact of queen quality on swarming tendency, correlation between royal jelly composition and swarming tendency.

Transcriptome analysis reveals key genes and pathways associated with egg production in Nandan-Yao domestic chicken

BackgroundEgg production is a very important economic trait in chicken breeding, but its molecular mechanism is unclear until now. Nandan-Yao chicken (Gallus gallus domesticus) is a native breed in Guangxi province, China, which is famous for good meet quality, but with low egg production. MethodsTo explore the molecular regulation related to egg production, high egg production (HEP) and low egg production (LEP) were divided according to the total egg number at 55 weeks, and the concentration of serum sex hormones was tested to evaluate the physiological function of ovary and uterus. RNA sequencing (RNA-Seq) was used to explore the transcriptome from the ovary and uterus of Nandan-Yao chicken. ResultsThe levels of serum sex hormone showed that concentrations of estradiol (E2), follicle-stimulating hormone (FSH), and luteotropic hormone (LH) were significantly higher in HEP than those in LEP (P < 0.01), while the concentration of testosterone (T) was significantly lower in HEP (P < 0.01). RNA-Seq analysis identified 901 and 2763 differentially expressed genes (DEGs) in ovary and uterus, respectively. Enrichment analysis showed that DEGs were significantly involved in the regulation of tight junction in the ovary (P < 0.05), while in uterus, DEGs were mainly enriched in the phagosome, ECM-receptor interaction, cell adhesion molecules (CAMs), focal adhesion, cardiac muscle contraction, cytokine-cytokine receptor interaction, and the regulation of MAPK signaling pathway (P < 0.05). Protein network interaction and function analyses revealed that FN1, FGF7, SOX2 identified from the ovary, and UQCRH, COX5A, FN1 from the uterus might be key candidate genes for egg production in Nandan-Yao chicken. ConclusionsOur study provided key candidate genes and pathways involved in the egg-laying process of Nandan-Yao chicken and could help to further understand the molecular mechanisms of chicken reproduction.

Effects of twice a day feeding and split feeding during lay on broiler breeder production performance, eggshell quality, incubation traits, and behavior

Eggshell quality of broiler breeders’ eggs decreases at the end of the laying period. Feeding a limited daily allowance of feed in the morning does not supply the necessary nutrients, particularly calcium for eggshell formation, at the right time of the day. Therefore, an experiment was conducted to study the effects of providing a standard diet twice a day or split feeding (special morning and afternoon diet) in broiler breeders on production performance, eggshell quality, incubation traits, and behavior. At 50 wk of age (WOA) 576 females and 48 males were randomly allotted to 24 floor pens and assigned to one of three treatments: 1) Standard breeder diet fed once a day (100% at 0730 h) (CON1x), 2) Standard breeder diet fed twice a day (50% at 0730 h and 50% at 1400 h) (CON2x), and 3) Split feeding fed twice a day, with a special morning (0730 h) and afternoon (1400 h) diet composition (SP2x). The morning diet was energetically comparable with the control diet, but it contained more protein and phosphorus (P) and less calcium (Ca). The afternoon diet had a lower energy, protein and P and a higher Ca content than the control and morning diet. The SP2x birds tended to have a higher egg production between 51 and 55 WOA (27.0 vs. 25.9 eggs; P = 0.088) compared to the CON1x birds, while the CON2x birds (26.6 eggs) did not differ from the other treatments. No differences were found on egg production for the total period (51–60 WOA) and on other production parameters. The different feeding strategies did not affect eggshell quality and incubation traits. However, the feeding strategies affected the behavioral patterns considerably. Twice a day feeding (CON2x and SP2x) resulted in more time spent on eating and sitting, and in less time spent on foraging and object pecking (P ≤ 0.05) compared to feeding once a day (CON1x). In conclusion, twice a day feeding improves behavior and split feeding improves both egg production and behavior in broiler breeders, however, no effects were observed on eggshell quality and incubation traits.

The effect of environmental factors on the productivity of Kampung Unggul Balitbangtan (KUB) chicken in Nusa Tenggara Timur (NTT)

Kampung Unggul Balitbangtan (KUB) Chicken is a selective range chicken with high egg production. This research aimed to determine the effect of environmental factors, i.e. wind speed, humidity, and temperature, on the productivity of chicken eggs Kampung Unggul Balitbangtan (KUB) layer 45-48 weeks. The research was conducted in October 2020, located in Assessment Institute for Agricultural Technology of Nusa Tenggara Timur (NTT). The data obtained by measurement and calculation of population data, egg production, and mortality. The result showed that the average environmental factors in wind speed, humidity, and temperature were 21.40 m/s, 79.50%, and 30°C. The average egg productivity, body weight, and KUB chicken mortality in the laying phase at 45-48 weeks were 33.56%, 1.684 kg, and four chicken/week. All environmental factors together affect the productivity of KUB chicken in Nusa Tenggara Timur.

The case for a wider range of flies for use in waste bioconversion

Bioconversion is the process whereby nutrients are recovered from organic waste products, often by flies, to produce value-added products such as protein for animal feed and lipids for biodiesel production. Currently, research and industry focus on a select few fly species for use in bioconversion that are generalists in their feeding behaviour, the black soldier fly,Hermetia illucens L., and the housefly,Musca domestica L. More investigation is needed on species of flies that are more suited to underutilised waste streams, including meat processing waste. Species of flies that breed in carrion, such as blowflies (Calliphoridae) and flesh flies (Sarcophagidae) can be used to reduce meat processing waste and produce a valuable source of protein. In this review, we propose more investigation and use of a wider range of fly species for bioconversion of organic waste. Four blowfly species are recommended for use in the bioconversion of meat processing waste or a mixture of manure waste and meat processing waste.Chrysomya chloropyga (Wiedemann) is a large mammal carcass specialist and has been found to be effective at recovering nutrients from abattoir waste within four days and producing large larvae in the process.Chrysomya putoria (Wiedemann) andChrysomya megacephala (Wiedemann) naturally breed in carrion and faeces, are associated with pit latrines and respond well under mass rearing conditions, with high egg production. These species would be recommended for a large-scale bioconversion facility that receives mixed waste streams including manure and animal remains.Lucilia sericata is known to produce antimicrobial compounds that assist in wound healing and has been frequently bred and studied and responds well to lab and mass rearing conditions. We recognise the potential obstacles to using alternative species in industrial-scale bioconversion facilities and pose future directions for research to overcome these challenges.

Evaluating the sustainability of egg production in Turkey: A standardized data approach

This study aimed to evaluate egg production systems within the scope of sustainability criteria under Turkey conditions. A standardized data approach was used to measure sustainability and compare egg production systems. The study covered a one-year egg-laying cycle of 24 farms including conventional cage, organic, and free-range systems. Hens in conventional cages had higher egg production and lower feed intake compared to hens in organic and free-range systems. The highest mortality was found in the free-range hens while the lowest was in the conventional cage system. All hens were fully feathered in the organic egg production system, which was followed, by free-range and conventional cage. This result led to a better social sustainability score for non-cage systems. Economic issues of sustainability had higher scores in conventional cage and organic egg production than those in the free-range system. The hen number per m2 in the total farm area was lower in organic and free-range than those in conventional cage systems (P=0.003), nonetheless, the total land occupation area was found similar. The standardized data used in this study shows that management practices should be improved in free-range and organic egg production systems to achieve higher sustainability scores in Turkey.

Time-Restricted Feeding in Commercial Layer Chickens Improves Egg Quality in Old Age and Points to Lack of Adipostat Activity in Chickens.

In mammals, time-restricted feeding (TRF) with no caloric restriction provides health benefits and extends longevity, usually with a minor (∼3%) or no reduction in total food consumption. In the current study, a TRF regimen of 6 h free access to food (08:00–14:00 h) was applied to Leghorn chickens from 25 to 86 weeks of age; control birds ate freely during the light hours (06:00–20:00 h). Unexpectedly, the TRF-treated birds consumed, on average, 11.7% less food than the controls. This was manifested by an average reduction of 9.6% in body weight, 2.6-fold in visceral fat accumulation, and 6.5% in egg weight. Hen-housed egg production was reduced by 3.6% in the TRF group compared with the control, along the first 40 weeks of the follow-up (P < 0.05), and changed into a tendency of 0.7% higher egg production thereafter. Several parameters of egg quality showed significant improvement (P < 0.05) in the TRF group compared with the controls. A comparison of diurnal patterns of feed consumption revealed a higher rate of hourly consumption in the TRF group and increased consumption before dark in the control group. In conclusion, the reduced feed intake in response to the TRF treatment and loss in visceral fat accumulation supports the lack of a strong adipostat activity in chickens and different appetite regulation mechanisms compared with mammals. Therefore, future TRF studies in chickens should be adjusted by extending the ad libitum time window. The lower feed intake by the TRF-treated chickens compared with the ad libitum-fed controls seems to reduce the efficiency of egg production. Nevertheless, the improved egg quality and persistence of egg lay at the older age suggest that similarly to mammals, the TRF treatment delayed at least some of the negative impacts associated with advanced age.

Hypothalamic and ovarian transcriptome profiling reveals potential candidate genes in low and high egg production of white Muscovy ducks (Cairina moschata)

In China, the low egg production rate is a major challenge to Muscovy duck farmers. Hypothalamus and ovary play essential role in egg production of birds. However, there are little or no reports from these tissues to identify potential candidate genes responsible for egg production in White Muscovy ducks. A total of 1,537 laying ducks were raised; the egg production traits which include age at first egg (days), number of eggs at 300 d, and number of eggs at 59 wk were recorded. Moreover, 4 lowest (LP) and 4 highest producing (HP) were selected at 59 wk of age, respectively. To understand the mechanism of egg laying regulation, we sequenced the hypothalamus and ovary transcriptome profiles in LP and HP using RNA-Seq. The results showed that the number of eggs at 300 d and number of eggs at 59 wk in the HP were significantly more (P < 0.001) than the LP ducks. In total, 106.98G clean bases were generated from 16 libraries with an average of 6.68G clean bases for each library. Further analysis showed 569 and 2,259 differentially expressed genes (DEGs) were identified in the hypothalamus and ovary between LP and HP, respectively. The KEGG pathway enrichment analysis revealed 114 and 139 pathways in the hypothalamus and ovary, respectively which includes Calcium signaling pathway, ECM-receptor interaction, Focal adhesion, MAPK signaling pathway, Apoptosis and Apelin signaling pathways that are involved in egg production. Based on the GO terms and KEGG pathways results, 10 potential candidate genes (P2RX1, LPAR2, ADORA1, FN1, AKT3, ADCY5, ADCY8, MAP3K8, PXN, and PTTG1) were identified to be responsible for egg production. Further, protein-protein interaction was analyzed to show the relationship between these candidate genes. Therefore, this study provides useful information on transcriptome of hypothalamus and ovary of LP and HP Muscovy ducks.

Transcriptome analysis of ovary tissues from low- and high-yielding Changshun green-shell laying hens

BackgroundChangshun green-shell laying hens are unique to Guizhou Province, China, and have high egg quality. Improving egg production performance has become an important breeding task, and in recent years, the development of high-throughput sequencing technology provides a fast and exact method for genetic selection. Therefore, we aimed to use this technology to analyze the differences between the ovarian mRNA transcriptome of low and high-yield Changshun green-shell layer hens, identify critical pathways and candidate genes involved in controlling the egg production rate, and provide basic data for layer breeding.ResultsThe egg production rates of the low egg production group (LP) and the high egg production group (HP) were 68.00 ± 5.56 % and 93.67 ± 7.09 %, with significant differences between the groups (p < 0.01). Moreover, the egg weight, shell thickness, strength and layer weight of the LP were significantly greater than those of the HP (p < 0.05). More than 41 million clean reads per sample were obtained, and more than 90 % of the clean reads were mapped to the Gallus gallus genome. Further analysis identified 142 differentially expressed genes (DEGs), and among them, 55 were upregulated and 87 were downregulated in the ovaries. KEGG pathway enrichment analysis identified 9 significantly enriched pathways, with the neuroactive ligand-receptor interaction pathway being the most enriched. GO enrichment analysis indicated that the GO term transmembrane receptor protein tyrosine kinase activity, and the DEGs identified in this GO term, including PRLR, NRP1, IL15, BANK1, NTRK1, CCK, and HGF may be associated with crucial roles in the regulation of egg production.ConclusionsThe above-mentioned DEGs may be relevant for the molecular breeding of Changshun green-shell laying hens. Moreover, enrichment analysis indicated that the neuroactive ligand-receptor interaction pathway and receptor protein tyrosine kinases may play crucial roles in the regulation of ovarian function and egg production.

Comparative Egg Production, Quality and Hatchability in Three Chicken Genotypes under Humid Tropical Conditions

Comparative study on egg production and hatchability characteristics in Nigerian local (NL; n=24), FUNAAB-α (F-α; n=24) and Transylvanian naked neck (TNN; n=24) chickens aged 25 weeks old was carried out for 4 weeks. Three hundred and sixty hatchable eggs each were used for quality characteristics determination and for incubation. F-α had significantly (P&lt;0.001) higher egg production (90.3%) than TNN (76.9%) while TNN was higher than NL (58.3%). Egg weight (EWT), length, width and surface area, albumen height, weight, percentage and index, shell weight, color and internal quality unit (IQU) were significantly (P&lt;0.001) affected by genotype. These followed the pattern: NL&lt;F-α&lt;TNN. F-α and TNN had significantly (P&lt;0.001) higher values than NL in egg shape index, yolk weight, height and diameter. Yolk colour index was significantly (P&lt;0.01) higher in TNN than in F-α. Yolk percentage and yolk-albumen ratio followed the pattern: NL&gt;F-α&gt;TNN. NL had (P&lt;0.001) thicker and higher shell percentage (SP) than F-α and TNN. Higher Haugh unit (HU) was recorded in TNN than in NL and F-α. Fertility was significantly (P&lt;0.05) higher in F-α than in TNN. Hatchability was not (P&gt;0.05) affected by genotype. Chick weight and chick: egg ratio were significantly (P&lt;0.001) by genotype. TNN had higher chick weight and yield than F-α and NL chicks. In conclusion, F-α laid more eggs than others, exhibited higher fertility with longer chicks at hatch. TNN is superior in EWT, HU, IQU and chick yield. NL had higher SP than others.&#x0D; Keywords: Egg production, Egg quality, FUNAAB alpha chicken, Hatchability, Transylvanian naked neck chicken.

Crossbred Local Chickens from East Nusa Tenggara Province Indonesia Under Semi Intensive Management System

The objective of this study was to compare the performance of four-breed combination under semiintensive management system. The experiment used 160 females and 40 males chickens as parents. Artificial insemination was performed to produce the experimental chicken of the four breed combinations (1. Sabu x Sabu, 2. Sabu x Semau, 3. Sabu x KUB, 4. Semau x KUB). The chickens were fed with chick starter crumb sad libitum from day old to 4 weeks of age. From 4-8 weeks of age, chickens were allowed to scavenge during the day, and also given commercial grower pellets + rice bran + corn (5:4:1). Combination of Sabu x KUBfrom 4-8 weeks of age were significantly heavier (P < 0.05) than the other combination breeds. Feed intake in the Sabu x KUB group was the lowest, and their weight gain was the highest among the others group(P < 0.05). The combination Sabu x KUB also had the highest egg production, and hatchability. However, the percentage of abdominal fat of Sabu x KUB were higher than others groups. In conclusion, combination Sabu x KUB had the best growth performance and egg production performance, but not for the percentage of abdominal fat.

Effect of liquid feed additive "Reasil® Humic Vet" on nutrient digestion in poultry farming

Reasil® Humic Vet is a liquid water-soluble feed additive with complex action. The aim of our research was to study the effect of the liquid feed additive "Reasil® Humic Vet" on the productive qualities and the digestibility of nutrients in compound feed by laying hens. The drug was drunk for 14 days with a break between courses of 7 days at a dose of 0.25, 0.50 and 0.75 ml / 1 liter of water. The highest egg production was obtained in chickens, the second experimental group -84.69%. The weight of 1 egg in this group also turned out to be higher than -63, 10 g. All this led to an increase in the egg weight to 31.09 kg, while reducing feed costs to 2.17 kg. The digestibility of organic matter in the experimental groups was 75.45, 75.44 and 75.37%, which is significantly higher than in the control group by 0.66, 0, 67 and 0.59%, respectively (P &lt;0.05). The drug used with a high degree of reliability stimulated an increase in the digestibility coefficients of protein, fat, fiber (P &lt;0.01) in chickens from 1 and 2 experimental groups. Increasing the amount of the supplement to the maximum dose did not significantly affect protein digestibility. Fat, fiber and dry matter in general in the 3rd experimental group had digestibility coefficients, the difference of which with those of the control group was confirmed by biometric processing (P &lt;0.05 and 0.01).

Influence of selection for egg production on egg quality traits in Japanese quail

The current study investigated the influence of selection for increased egg production on external and internal egg quality traits over five generations in Japanese quail. A total of 4325 fresh eggs from 1326 females were collected each week during the egg-laying period to estimate heritability, genetic and phenotypic correlations, and correlated response of external and internal egg quality traits to selection for egg number (EN). The direct response to selection indicated an increase of 7.7 ± 0.27 eggs produced during the 90 days following production of the first egg. The correlated responses to selection indicated that selection for higher EN can be expected to increase EW and increase egg quality. Estimates of heritability ranged from 0. 11 to 0.35 for external egg quality traits and from 0.08 to 0.32 for internal egg quality traits. Estimates of the genetic correlations of EN with external and internal traits were positive, ranging from 0.09 to 0.25 and from 0.02 to 0.27, respectively. These estimates indicated few if any genetic antagonisms that would adversely affect selection response. However, eggshell thickness would not be expected to change as a result of selection for EN. Thus, the external and internal quality of Japanese quail eggs could be improved by selection for high egg production.

Comparative Transcriptome Profiling of mRNA and lncRNA of Ovaries in High and Low Egg Production Performance in Domestic Pigeons (Columba livia).

Egg production performance is one of the most important economic traits in pigeon industry. However, little is known regarding how egg production performance is regulated by long non-coding RNAs (lncRNAs) in pigeons. To evaluate the lncRNAs and mRNAs in ovaries associated with egg production performance in domestic pigeons, high-throughput RNA sequencing of ovaries between high and low egg production performance groups were performed and analyzed in this study. A total of 34,346 mRNAs and 24,601 lncRNAs were identified, including 14,525 known lncRNAs and 10,076 novel lncRNAs, of which 811 mRNAs and 148 lncRNAs (P < 0.05) were significantly differentially expressed (DE) between the groups of high and low egg production performance. GO and KEGG annotation analysis indicated that the target genes of DE lncRNAs and DE mRNAs were related to cell differentiation, ATP binding and methylation. Moreover, we found that FOXK2, a target gene of lncRNA MSTRG.7894.4, was involved in regulating estrogen receptors. Our study provided a catalog of lncRNAs and mRNAs associated with egg production performance, and they deserve further study to deepen the understanding of biological processes in the ovaries of pigeons.

Transcriptome Analysis During Follicle Development in Turkey Hens With Low and High Egg Production.

Low and high egg producing hens exhibit gene expression differences related to ovarian steroidogenesis. High egg producing hens display increased expression of genes involved in progesterone and estradiol production, in the granulosa layer of the largest follicle (F1G) and small white follicles (SWF), respectively, whereas low egg producing hens display increased expression of genes related to progesterone and androgen production in the granulosa (F5G) and theca interna layer (F5I) of the fifth largest follicle, respectively. Transcriptome analysis was performed on F1G, F5G, F5I, and SWF samples from low and high egg producing hens to identify novel regulators of ovarian steroidogenesis. In total, 12,221 differentially expressed genes (DEGs) were identified between low and high egg producing hens across the four cell types examined. Pathway analysis implied differential regulation of the hypothalamo-pituitary-thyroid (HPT) axis, particularly thyroid hormone transporters and thyroid hormone receptors, and of estradiol signaling in low and high egg producing hens. The HPT axis showed up-regulation in high egg producing hens in less mature follicles but up-regulation in low egg producing hens in more mature follicles. Estradiol signaling exclusively exhibited up-regulation in high egg producing hens. Treatment of SWF cells from low and high egg producing hens with thyroid hormone in vitro decreased estradiol production in cells from high egg producing hens to the levels seen in cells from low egg producing hens, whereas thyroid hormone treatment did not impact estradiol production in cells from low egg producing hens. Transcriptome analysis of the major cell types involved in steroidogenesis inferred the involvement of the HPT axis and estradiol signaling in the regulation of differential steroid hormone production seen among hens with different egg production levels.

Effect of different concentrations of neohesperidin dihydrochalcone on performance, egg quality, serum biochemistry and intestinal morphology in laying hens

In recent years, neohesperidin (NH), as a class of natural flavonoids, has received more and more attention in nutrition research. However, the research on the application of neohesperidin in the laying hens is rarely reported. This study was conducted to determine the effects that different concentrations of dietary NH have on the production performance, egg quality, serum biochemistry and intestinal morphology of laying hens. A total of 240 Lohmann commercial laying hens (66 wk old) were divided into 4 groups, with each group's diet containing a different concentration of NH (0, 100 mg/kg, 200 mg/kg, and 400 mg/kg). Significant associations were found between NH consumption and both higher egg production (P = 0.050) and lower FCR (P = 0.028) after 12 wk NH feed. At 12 wk, eggs produced by hens consuming a 200 mg/kg NH diet had significantly thicker eggshells (P = 0.059) than those produced by hens consuming a 400 mg/kg diet. Dietary NH addition improved albumen height and Haugh unit after 15 d of storage (P < 0.01). However, no significant associations between NH consumption and these factors were identified after 12 wk. Dietary NH addition had no significant effects apparent of gel properties at 12 wk. In addition, NH can effectively reduce the content of total cholesterol (TC) (P = 0.042) and Groups treated with 100 mg/kg NH supplementation showed significantly increased T-AOC concentrations compared to control (P = 0.013) in serum. Hens fed an NH-supplemented diet exhibited a longer villus height and a higher villus/crypt ratio in the ileum (P < 0.01) as compared to controls, as well as lower crypt depth in the duodenum, jejunum and ileum. These results indicate that, as compared to a control diet, an NH-supplemented diet results in higher egg production and quality, as well as improvement in egg gel properties, serum biochemistry and intestinal morphology.

Trophic niche variability influences body condition of female Atlantic cod (Gadus morhua) on organosomatic and biochemical levels

Body condition and energy reserves are important indicators of organism health, habitat suitability and predictors for the reproductive success in fish. In Greenland waters, Atlantic cod (Gadus morhua) inhabits different habitats in shallow and deep parts on top of the shelf and along slopes, where diet composition differs. We investigated the influence of habitat heterogeneity and trophic niche on body condition using organosomatic indicators, e.g. the morphometric index K, hepatosomatic and gonadosomatic indices, and biochemical indicators, e.g. lipid content and fatty acid compositions, of mature female cod. Body condition differed between sites and peaked in north-eastern regions in depths below 300 m towards the slope of the northern Irminger Sea. Trophic niches as indicated by stable isotope values and stomach composition data varied between sites, which was likely related to depth and differences between benthic and pelagic feeding regimes. Total lipid content and fatty acid profiles important for reproduction were associated with a pelagic diet comprised of mesopelagic fish and crustaceans. Interestingly, consumption of capelin was not linked to highest energy reserves as indicated by traditional body condition indices, such as K and the hepatosomatic index, but lowest ratios of eicosapentaenoic acid to arachidonic acid in gonads, which are known to be beneficial for high egg production. This shows that body condition on biochemical level can differ from conventionally used indices, which emphasizes the need to take fatty acid composition into account, when investigating condition and reproductive potential in cod. Our results emphasize that the factor habitat cannot be ignored for population replenishment of the cod stocks in Greenland waters and indicate that capelin as part of an Arcto-boreal diet benefits reproductive success in cod.