Differences In Egg Production Research Articles

Usability of Hemp Plant in Poultry Nutrition

Hemp (Cannabis sativa L.) is an annual plant with 2n=20 chromosomes, one-year, C3 group, cultivated for its long and strong fibers and seeds. It is a plant that should be cultivated in a controlled manner due to the presence of THC in its natural structure. Producers who avoid control and monitoring have turned to alternative products instead of hemp farming. Countries that cultivate cannabis in large areas; France, China, and Canada. Some countries are updating their cannabis-related laws and making efforts to increase hemp acreage. It is known that hemp farming has been practiced in Anatolia since 1500 BC. Various products such as hemp seeds, hemp pulp, hemp oil have been used in various studies in poultry feeding studies, while no negative results have been encountered, but various positive results have been suggested and their use is recommended. It is of great importance to investigate the effects of cannabidiols, which have strong antimicrobial, antioxidant and immunostimulant effects, as they are expected to support the immune system in poultry, especially broilers. Some of the studies in which hemp products are used in poultry nutrition are as follows; Addition of hemp meal to laying hen diets has been reported to make no significant difference in egg production, feed consumption, feed utilization, body weight gain or egg quality, but results in lower palmitic acid concentrations and higher Linoleic acid (LA) and alpha-linolenic acid (ALA) concentrations, which are healthier for human consumption. Hemp seeds and hemp oil used in chicken rations caused an increase in the omega-3 polyunsaturated fatty acid content and color intensity of egg yolks, but no adverse effects were observed on the sensory profiles of cooked eggs. Addition of cannabis meal to fast growing broiler diets did not affect performance or mortality, and no effect on the number of Clostridium perfringens in the cecum was reported. Hemp seeds have a remarkable effect on the growth of broiler chicks and can help reduce feed expenditures for broiler rearing. In this paper, the use and usability of the hemp plant, whose production areas are expanding rapidly, in poultry will be examined.

Building methodological consensus to ensure rigor and reproducibility in zebrafish fertility research

The summary included in the text: Zebrafish are an increasingly popular model for studying the genetic and environmental factors that shape male and female fertility; however, the field currently lacks a standardized approach to fertility assessment. The current lack of consensus makes comparisons across studies more challenging and is an obstacle to reproducibility in the fields of reproductive biology and toxicology. Here, we review the diversity of spawning approaches used in zebrafish reproductive toxicology research to asses fertility and provide evidence that spawning parameters can result in meaningful differences in egg production and spawning success.

Ecotoxicological Assays with the Calanoid Copepod Acartia tonsa: A Comparison between Mediterranean and Baltic Strains

The use of marine invertebrates in ecotoxicology is important for an integrated approach which takes into consideration physiological responses and chemical levels in environmental matrices. Standard protocols have been developed and organisms belonging to different trophic levels are needed as model organisms to evaluate toxicant bioavailability and assess their impact on marine biota. The calanoid copepod Acartia tonsa is commonly used in ecotoxicology due to its widespread distribution and well-studied biology. However, different strains coming from various geographical areas are available, and possible variations in physiological characteristics raise concerns about the comparability of ecotoxicological results. This study compares the life cycle assessment and sensitivity of Adriatic and Baltic strains of A. tonsa exposed to nickel (Ni2+) in standardized acute and semi-chronic tests. Life cycle assessments revealed differences in egg production, egg-hatching success, and naupliar viability between the strains. The acute toxicity test demonstrated the significantly higher sensitivity of Adriatic strain nauplii to Ni2+ compared to the Baltic strain, whereas the semi-chronic test showed no significant difference in sensitivity between the strains. These findings suggest that while strain-specific differences exist in different geographical populations, responses to toxicants are not significantly different. Particularly, the semi-chronic assessments with both A. tonsa strains emphasized the robustness of this species as a model organism in ecotoxicology.

Genome-wide selective signatures mining the candidate genes for egg laying in goose

BackgroundImproving the egg production of goose is a crucial goal of breeding, because genetics is the key factor affecting egg production. Thus, we sequenced the genomes of 55 Chinese indigenous geese from six breeds, which were divided into the high egg-laying group (ZE, HY, and SC) and low egg-laying group (ZD, LH, and ST). Based on the results of the inter-population selection signal analysis, we mined the selected genome regions in the high egg-laying germplasm population to identify the key candidate genes affecting the egg-laying traits.ResultsAccording to the whole-genome sequencing data, the average sequencing depth reached 11.75X. The genetic relationships among those six goose breeds coincided with the breed’s geographical location. The six selective signal detection results revealed that the most selected regions were located on Chr2 and Chr12. In total, 12,051 single-nucleotide polymorphism (SNP) sites were selected in all six methods. Using the enrichment results of candidate genes, we detected some pathways involved in cell differentiation, proliferation, and female gonadal development that may cause differences in egg production. Examples of these pathways were the PI3K-Akt signaling pathway (IGF2, COMP, and FGFR4), animal organ morphogenesis (IGF2 and CDX4), and female gonad development (TGFB2).ConclusionOn analyzing the genetic background of six local goose breeds by using re-sequencing data, we found that the kinship was consistent with their geographic location. 107 egg-laying trait-associated candidate genes were mined through six selection signal analysis. Our study provides a critical reference for analyzing the molecular mechanism underlying differences in reproductive traits and molecular breeding of geese.

Effect of substituting synthetic methionine and lysine with herbal, with adding thyronine by 120% in low-protein diets of laying hens on productive and some blood traits.

A total of 160 Lehman Brown layer 45 weeks dy completely randomized with five replicates (cages in battery system) each replicates contain of four birds and the period of this experiment was 112 days, The nutritional treatments were , T1: basal diet (control) contained 16.32% cruds protein (C.P) with 0.41% synthetic methionine (S.Thrionine) , T2: basal diet (16.32% C.P) with (0.41%) herbal methionine (H.M) and (0.106% S.Thironine) . T3 : basal diet (16.18%C.P) with (0.42%S.Mthionine ), (0.05% herbal lysine :H.L) and (0.106% S.Thrionine) T4: basal diet (16.18% C.P) with (0.42% H.methionine), (0.05%H.Lysine) and (0.106% S.Thrionine) , T5: basal diet (15.45%C.P) with ( o.42% S .methionine) , 0.12% S.Lysine ) and (0.116% S.thronine ) T6: basal diet (15.46% C.P) with (0.42% H.methionine),(0.045% H.Lysine) and S. threonine ), T7: basal diet (15.12%C.P) With (0.148% S.methionine , (0.150% S.lysine ) and (0.130% S.thrionine ) ,T8: basal diet (15.12%C.P) with (0.148% H.methionine ) , (0.150%H.lysine) and (0.130% S.thrionine , The experiment showed that there were no differences in egg production and egg mass between treatments, while significant differences were found in egg weight between treatments. , While no differences appeared between the treatments for the characteristic of shell thickness, specific weight of shell, and egg shape index, nor did significant differences appear in the biochemical properties of blood serum..

Ovary transcriptome profiling in high- and low-yielding Chinese Chahua laying chickens

This study aimed to explore the underlying reasons for the differences in egg production in Chinese Chahua chickens. The Chahua chicken population was divided into two groups, namely a high-yielding group (H) and a low-yielding group (L). The egg-laying performance, ovarian morphology, histological characteristics, and serum hormone concentrations in the H and L groups were analysed. The results revealed that there were significant differences (P < 0.01) between the two groups for the age at the first egg and the number of eggs. The H group showed significantly more (P < 0.01) hierarchical follicles and small yellow follicles than the L group. While several secondary follicles and primary follicles were observed in the ovaries of the H group, only a few secondary follicles were observed in the ovaries of the L group. The serum concentrations of the follicle-stimulating hormone, the luteinising hormone, and oestradiol were significantly higher in the H group compared to that in the L group (P < 0.01). Next, we sequenced and analysed the ovarian expression profiles in the two groups using RNA-seq. The transcriptome sequencing revealed 875 differentially expressed genes (DEGs) between the H and L groups. Of the 875 DEGs, 624 were up-regulated, and 251 were down-regulated. The DEGs were mapped to 31 Gene Ontology (GO) terms and 15 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for the ovarian tissue. The KEGG pathway analysis mainly revealed the involvement of focal adhesion, cytokine-cytokine receptor interaction, and the TGF-beta signalling pathway, while the GO analysis mainly showed involvement of the hormonal activity, extracellular matrix, and extracellular region. Our results showed that understanding the differences in the gene expressions between the ovarian tissues of high- and low-yielding hens may provide a useful reference for improving the egg-laying performance in Chahua chickens.

Interspecies Isobaric Labeling-Based Quantitative Proteomics Reveals Protein Changes in the Ovary of Aedes aegypti Coinfected With ZIKV and Wolbachia.

Zika is a vector-borne disease caused by an arbovirus (ZIKV) and overwhelmingly transmitted by Ae. aegypti. This disease is linked to adverse fetal outcomes, mostly microcephaly in newborns, and other clinical aspects such as acute febrile illness and neurologic complications, for example, Guillain-Barré syndrome. One of the most promising strategies to mitigate arbovirus transmission involves releasing Ae. aegypti mosquitoes carrying the maternally inherited endosymbiont bacteria Wolbachia pipientis. The presence of Wolbachia is associated with a reduced susceptibility to arboviruses and a fitness cost in mosquito life-history traits such as fecundity and fertility. However, the mechanisms by which Wolbachia influences metabolic pathways leading to differences in egg production remains poorly known. To investigate the impact of coinfections on the reproductive tract of the mosquito, we applied an isobaric labeling-based quantitative proteomic strategy to investigate the influence of Wolbachia wMel and ZIKV infection in Ae. aegypti ovaries. To the best of our knowledge, this is the most complete proteome of Ae. aegypti ovaries reported so far, with a total of 3913 proteins identified, were also able to quantify 1044 Wolbachia proteins in complex sample tissue of Ae. aegypti ovary. Furthermore, from a total of 480 mosquito proteins modulated in our study, we discuss proteins and pathways altered in Ae. aegypti during ZIKV infections, Wolbachia infections, coinfection Wolbachia/ZIKV, and compared with no infection, focusing on immune and reproductive aspects of Ae. aegypti. The modified aspects mainly were related to the immune priming enhancement by Wolbachia presence and the modulation of the Juvenile Hormone pathway caused by both microorganism’s infection.

Impact of Organic Zinc and Vitamin-E Supplementation on Production Performance, Egg Quality and Hatching Traits of Japanese Quail

The objective of current study was to investigate the effects of Zn (organic and inorganic) and Vitamin-E on egg production, quality and hatchability of Japanese quails. The experiment carried out for a period of 12 weeks, total of 640 7 weeks old quails were randomly assigned to eight (80 quails in each) different dietary treatments A (control), B, C, D, E, F, G and H under completely randomized design (CRD). Each treatment group was further replicated into four sub units with twenty quails in each (comprising five male and fifteen female). The results revealed that adding Zinc+Vit-E to diets caused a significant effect (P<0.05) on weekly egg production, while the difference in egg production due to interactive effect of weeks × treatments was insignificant (P>0.05). Average weekly egg production was significantly greater (P<0.05) in group H (82.45/bird), followed by group F (78.27), G (77.93) and E (77.50/bird). Relatively lower egg production of 77.22, 76.97, 76.41and 74.14/bird was recorded in groups D, C and A respectively. Whereas, diets had insignificant effect (P>0.05) on egg exterior quality including (weight, length, width and shape index) as well as interior quality (albumen height, width, yolk weight, height, and width). However, the dietary Zn and Vit-E had a significant effect on egg hatchability percentage (P<0.05). The higher hatchability percentage was observed in group H (75.66 %) followed by F, E and G (72.33, 70.0 and 67.25 percent) respectively. While, the lower hatchability % was in group B (62.75), C (62.0), D (56.17) and control A (50.42%). Supplementary dietary treatments showed significant effects (P<0.05) on dead germs. Results indicates that dead embryos were least (5.00) in group H, followed by groups F , E and G as 6.41, 7.50 and 7.75 dead germs, respectively were examined. Similar pattern was also observed for dead chicks in eggs shell affected by feeding dietary treatments. Significantly the highest hatched chick weight (9.21 g) was obtained in group H than in groups F, E and G, where recorded 9.16, 9.03 and 9.02 g respectively. The average chick weight declined to 8.97, 8.96 and 8.92 g in groups B, C and D respectively; while the least average chick weight (8.92 g) was recorded in control (A). The current finding revealed that supplementation of Zn (organic and inorganic) and Vitamin E had significant effect on Japanese quail egg production, quality and hatchability reread under different dietary treatments.

Differences in egg yolk precursor formation of Guangxi Ma chickens with dissimilar laying rate at the same or various ages

Egg yolk formation and deposition are quite vital for oocyte maturation and egg production in hens. There are great differences in egg production and number of preovulatory follicles among individuals in Guangxi Ma chickens at the same or various ages, however, the causes of this phenomenon remain unclear. This study aimed to elucidate the differences in yolk precursors formation among Guangxi Ma hens at the same or various ages with dissimilar egg laying rate via comparing the synthesis and transportation of yolk precursors, serum estradiol (E2) levels, as well as the antioxidant capacity of the liver and serum from hens of 32-week-old (32W), 50-week-old with higher laying rate (50WH), 50-week-old with lower laying rate (50WL), 72-week-old with higher laying rate (72WH), and 72-week-old with lower laying rate (72WL). The results showed that the contents of triglyceride (TG), total cholesterol (T-CHO), high density lipoprotein cholesterol (HDL-C) and very low density lipoprotein cholesterol (VLDL-C) in the liver, serum and ovarian stroma, serum E2 levels, expression levels of proteins and genes related to yolk precursors formation, and the antioxidant capacity of liver and serum decreased significantly during aging process. TG, HDL-C and VLDL-C contents in serum and ovarian stroma, as well as HDL-C and VLDL-C levels in liver tissues of hens in 50WL and 72WL were significantly lower compared to hens in 50WH and 72WH, respectively. Meanwhile, expression levels of estrogen receptor ɑ and transcription levels of genes related to lipid transportation in liver tissues, and the antioxidant capacity of livers were remarkably lower in hens in 50WL and 72WL than those in 50WH and 72WH, respectively. However, no significant difference was detected in liver TG levels, serum E2 levels, genes related to fatty acids synthesis and serum antioxidant capacity between hens in 50WL and 50WH. In conclusion, the age-related decline of egg production in Guangxi Ma chicken maybe related to the age-related decreases in the synthesis and transportation of liver yolk precursor as well as the antioxidant capacity of liver and hens. And the non-age related decline of egg production may mainly attribute to the decreases in yolk precursors transportation ability and hepatic antioxidant capacity.

Effect of dietary flaxseed meal supplemented with dried tomato and grape pomace on performance traits and antioxidant status of laying hens

This study was carried out to determine the effect of dietary flaxseed meal (FSM) supplemented with dried tomato pomace (DTP) and dried grape pomace (DGP) on performance, egg quality, biochemical parameters traits and antioxidant status of laying hens. Birds (1825 ± 87 g of body weight) were divided into 12 dietary groups with six replicates per group (eight birds per replicate), under a completely randomized design with factorial arrangement 2 × 3 × 2 consisted of two levels of DTP (0 and 15%), three FSM levels (0, 4 and 8%) and two levels of DGP (0 and 5%). As a result of this study, there were no significant differences in egg production and weight as well in feed conversion ratio (FCR) among treatments (p > 0.05). Feeding of DGP reduced significantly feed intake and egg mass when compared to control group (p < 0.05). There was no effect (p > 0.05) of dietary treatment on shell thickness and strength, shape index, Haugh unit and egg specific gravity. Hens consuming 15% DTP and 5% DGP revealed a significantly higher yolk color compared to the other dietary treatments (p < 0.05). Moreover, there was no difference among dietary treatments in terms of serum low-density lipoprotein cholesterol (LDL) and high-density lipoprotein cholesterol (HDL) cholesterol, atherogenic index, triglycerides, total cholesterol levels (p > 0.05). Serum antioxidant parameters as glutathione peroxidase (GSH-Px) activity, malondialdehyde (MDA), total superoxide dismutase (TSOD) and total antioxidant capacity (T-AOC) were not influenced by treatments (p > 0.05). Based on findings, FSM and DTP supplements did not significantly impact most of hens’ performance indicators and egg quality parameters, whereas significant improvements were observed by feeding of 15% DTP and 5% DGP on egg traits, in particular on egg-yolk color that plays a key-role in consumer’s choice. However, the supplementation of FSM and DTP or DGP even in laying hen diet is still controversial and further research is needed.

Effect of Post-Hatch Heat-Treatment in Heat-Stressed Transylvanian Naked Neck Chicken.

Simple SummaryHeat stress due to high environmental temperature negatively influences animal productivity. Extensive studies have been carried out to evaluate the mechanisms of heat stress in chickens. It was shown that the expression level of heat-shock factors (HSFs) and heat-shock proteins (HSPs) were affected. Tissue-specific responses to the thermal challenge were also found in the heart, liver and muscle. Our study examined the changes in primary production parameters and four heat-shock factor and two heat-shock protein expression profiles in chicken gonads. In the first experiment, 24 h after hatching, 80 Transylvanian Naked Neck chickens were heat-treated at 38.5 °C ambient temperature with 60% humidity for 12 h. In this experiment, we studied the primary productivity parameters of matured chickens after the performed heat stress. In the second experiment, the heat treatment was the same, and we examined the expression pattern of heat-shock factors and heat-shock proteins in the control and treated gonads. We collected the samples immediately after the heat-treatment in case of half of the treated and control group. We found a significant difference in egg production, and increased expression level of HSP90 and HSF4 in heat-treated female gonads.Although numerous studies reported the effects of heat stress in chickens, it was not investigated in the Transylvanian Naked Neck breed. In our research, Transylvanian Naked Neck chickens, 24 h after hatching, were heat-treated at 38.5 °C for 12 h. We compared the control and heat-treated adult chickens’ productivity parameters following 12 weeks of heat-stress at 30 °C. We found that the heat-treated layers had significantly higher egg production in heat stress, but in cockerels, the sperm quality did not differ significantly between the two groups. To detect the effect of heat-treatment on a molecular level, the expression of two heat-shock proteins and four heat-shock factors were analysed in the gonads of control and heat-treated chickens. We found that the expression level of HSP90 and HSF4 increased significantly in heat-treated female chicken gonads. Still, in adult females, the expression of HSF2 and HSF3 were substantially lower compared to the control. In adult heat-treated males, the HSP70, HSF1 and HSF3 expression levels showed a significant increase in both gonads compared to the control. We think that the presented significant differences in egg production might be related to the increased expression level of HSP90 and HSF4 in heat-treated female gonads.

Effect of dietary coated granules containing garlic oil diallyl disulphide and diallyl trisulphide on performance, in vitro digestibility and gastrointestinal functionality in laying hens

This experiment was conducted to investigate the effects of dietary supplementation with coated granules (CG) on performance, in vitro digestibility and the gastrointestinal functionality in laying hens. A total of 40 Hisex Brown laying hens (36weeks of age) were randomly divided into five equal groups; one served as a control and the other four were actual experimental groups supplemented with 0.75, 1.5, 3 or 6g CG per day. All the hens were fed restrictively with target feed intake of 100g basal diet/hen per day. There were no differences in egg production or egg weight among the groups, but feed conversion ratio was significantly improved (linearly, p<0.05) with the dose level of CG in diet. Dietary CG increased the jejunal weight (linear and quadratic terms, p<0.05) but decreased the ileal weight (linearly, p<0.05). There was mostly statistical interaction between dietary CG and specific activity of intestinal digestive enzymes with similar patterns for dietary CG treatments (p<0.05). A positive linear correlation was observed with in vitro protein digestibility by using the crude enzyme extract from dietary CG supplementation. Dietary CG decreased the caecal Escherichia coli population while the Lactobacillus spp.: E.coli ratio increased (quadratic fit, p<0.05). CG supplementation, on the other hand, significantly altered intestinal morphology by increasing the height of duodenal and ileal villi (linearly, p<0.05). Also, duodenal antioxidant capacity observed via remaining reducing power improved linearly (p<0.05). This suggests that CG, unlike garlic oils without encapsulation, may be a good candidate for feed supplementation in commercial egg production. It could be included up to 6g CG per day without any adverse effects on performance, which may relate to improving nutrient digestibility and better utilization of limited feed intake when using a low amount of diet or other observations in this study.

Consequences of trait-selective fisheries on population reproductive potential: An experimental approach

The vulnerability of fish to fishing depends on a range of life-history (e.g. growth; reproduction), behavioural (e.g. boldness) and physiological (e.g. metabolic rates) traits which are usually correlated with reproductive success. Therefore, between-fish differences in catchability may be indirectly affecting the reproductive potential at the population level by removing certain phenotypes. The present study aims to test this hypothesis by assessing the relationship between vulnerability-to-angling and reproductive potential. We first scored the vulnerability-to-angling of a set of Serranus scriba adult individuals (n = 78), a species targeted by recreational fisheries, using intensive multi-event tests. The fish were then divided into three categories: high, medium and low vulnerability. Fish differing only in their vulnerability degree (i.e. the same average size and culture conditions) were kept in tanks (n = 6; two tanks per category). We monitored the tanks throughout a full spawning season to assess differences in seasonal distribution of spawning, total egg production, egg viability and egg quality. Fish with different vulnerability showed no significant differences in egg production (in terms of spawning seasonality and total eggs released) nor on egg viability compared to vulnerable fish. However, low vulnerability fish produced eggs with bigger egg yolk compared to high vulnerability fish but only toward the end of the fishing season. We interpret this difference as part of a portfolio effect in terms of behaviour and reproductive success, i.e., in unexploited populations, low vulnerability fish may contribute little to year class strength in typical years but act as a buffer, if a disturbance affects reproductive success early in the season. Moreover, although our work is based on a captivity experiment, the results are consistent with the hypothesis that harvested populations may compensate for the harvested biomass by investing more energy per fish in reproduction.

Comparative analysis of hypothalamus transcriptome between laying hens with different egg-laying rates

Egg-laying performance is one of the most important economic traits in the poultry industry. Commercial layers can lay one egg almost every day during their peak-laying period. However, many Chinese indigenous chicken breeds show a relatively low egg-laying rate, even during their peak-laying period. To understand what makes the difference in egg production, we compared the hypothalamus transcriptome profiles of Lushi blue-shelled-egg chickens (LBS), a Chinese indigenous breed with low egg-laying rate and Rhode Island Red chickens (RIR), a commercial layer with relatively high egg-laying rate using RNA-seq. A total of 753 differentially expressed genes (DEGs) were obtained. Of these DEGs, 38 genes were enriched in 2 Gene Ontology (GO) terms, namely reproduction term and the reproductive process term, and 6 KEGG pathways, namely Wnt signaling pathway, Oocyte meiosis, GnRH signaling pathway, Thyroid hormone signaling pathway, Thyroid hormone synthesis and MAPK signaling pathway, which have been long known to be involved in egg production regulation. To further determine the core genes from the 38 DEGs, protein-protein interaction (PPI) network, co-expression network and transcriptional regulatory network analyses were carried out. After integrated analysis and experimental validation, 4 core genes including RAC1, MRE11A, MAP7 and SOX5 were identified as the potential core genes that are responsible for the laying-rate difference between the 2 breeds. These findings paved the way for future investigating the mechanism of egg-laying regulation and enriched the chicken reproductive regulation theory.

Phase-related differences in egg production of the migratory locust regulated by differential oosorption through microRNA-34 targeting activinβ

Outbreaks of locust plagues result from the long-term accumulation of high-density egg production. The migratory locust, Locusta migratoria, displays dramatic differences in the egg-laid number with dependence on population density, while solitarious locusts lay more eggs compared to gregarious ones. However, the regulatory mechanism for the egg-laid number difference is unclear. Herein, we confirm that oosorption plays a crucial role in the regulation of egg number through the comparison of physiological and molecular biological profiles in gregarious and solitarious locusts. We find that gregarious oocytes display a 15% higher oosorption ratio than solitarious ones. Activinβ (Actβ) is the most highly upregulated gene in the gregarious terminal oocyte (GTO) compared to solitarious terminal oocyte (STO). Meanwhile, Actβ increases sharply from the normal oocyte (N) to resorption body 1 (RB1) stage during oosorption. The knockdown of Actβ significantly reduces the oosorption ratio by 13% in gregarious locusts, resulting in an increase in the egg-laid number. Based on bioinformatic prediction and experimental verification, microRNA-34 with three isoforms can target Actβ. The microRNAs display higher expression levels in STO than those in GTO and contrasting expression patterns of Actβ from the N to RB1 transition. Overexpression of each miR-34 isoform leads to decreased Actβ levels and significantly reduces the oosorption ratio in gregarious locusts. In contrast, inhibition of the miR-34 isoforms results in increased Actβ levels and eventually elevates the oosorption ratio of solitarious locusts. Our study reports an undescribed mechanism of oosorption through miRNA targeting of a TGFβ ligand and provides new insights into the mechanism of density-dependent reproductive adaption in insects.

Volitional tank spawning of domestic striped bass (Morone saxatilis) using human chorionic gonadotropin (hCG) and gonadotropin releasing hormone analogue (GnRHa)- induced ‘pace-setting’ females

Seventy-one tank spawning trials were conducted to evaluate the efficacy of exogenous hormone compounds and a novel “pace-set” strategy for inducing volitional tank spawning behavior in 5th generation domestic striped bass. Female fish (4.74 ± 0.73 kg; mean ± standard deviation) were treated with human chorionic gonadotropin (hCG; 29 trials), gonadotropin releasing hormone analog (GnRHa; 39 trials) or received no hormone treatment (control; 3 trials). Spawning trials were conducted using single females placed in spawning tanks with two (12 trials) or three (38 trials) males or with paired females placed in spawning tanks with three (4 trials) males. Significant differences in egg production, fry production, hatching rate, and fry/kg female body weight were generally not observed between exogenous hormone treatment groups (alpha = 0.05), with the exception of egg production differing between paired females spawning with three males (Student's t-test, p = 0.0255). However, a trend suggesting that increasing the number of males or females within the tanks improves yield of larvae (fry/kg female body weight) was observed. The untreated control females failed to spawn within 7 days. The pace-set spawning was conducted whereby one female treated with either hCG (7 trials) or GnRHa (7 trials) was placed in a spawning tank with one untreated female and multiple males. The results of these trials show for the first time that a hormone-induced female striped bass can be used to stimulate successful volitional spawning of an untreated female in the same tank with fry/kg female body weight production similar to that of hormone-treated fish. Microsatellite-based parentage of select tank spawns and four additional trials conducted with an increased number of males (19 trials total) showed that female striped bass typically spawn with at least two males; a single pair mating was only observed for one spawning trial. These data allowed for the determination of effective broodstock size (Nb) of each tank spawning trial at between 2.00 and 5.60 when considering all male contributions. The Nb generally increased as the number of males and female fish in the tank increased (from 2.53 for one female and two males to 5.52 for two females and six males). These results indicate that domestic striped bass are promiscuous and will generally reproduce in captivity using tank spawning procedures that allow for a high level of genetic diversity to be retained among the offspring. The pace-set method reduces hormone use and may be applied to commercial striped bass production as well as captive spawning of other fish species.

Differences in invitro responses of the hypothalamo–pituitary–gonadal hormonal axis between low- and high-egg-producing turkey hens

Low-egg-producing hens (LEPH) ovulate less frequently than high-egg-producing hens (HEPH) and exhibit differences in mRNA levels for components of the hypothalamo–pituitary–gonadal (HPG) axis, suggesting differential responsiveness to trophic stimulation. Ovulation frequency is governed by the production of the pituitary gonadotropins and feedback of the ovarian follicle steroid hormones, which are regulated by HPG axis stimulation and inhibition at the hypothalamic level. The pituitary and follicle cells from LEPH and HEPH were subjected to in vitro hormonal treatments to stimulate or inhibit the HPG axis, followed by expression analysis of mRNA levels for HPG axis genes and radioimmunoassays for steroid hormone production. Statistical analysis was performed using the mixed models procedure of SAS. The pituitary cells from HEPH showed upregulation of genes associated with ovulation stimulation, whereas cells from LEPH showed upregulation of genes associated with inhibition of ovulation. High-egg-producing hens’ follicle cells displayed a higher sensitivity and responsiveness to gonadotropin treatment. Level of egg production impacted ovulation-related gene expression in the pituitary cells as well as steroid hormone production in the follicle cells, with HEPH displaying a greater positive response to stimulation. These findings indicate that differences in egg production among turkey hens likely involve differential responsiveness of the cells within the HPG axis.

Ovarian transcriptomic analysis and follicular development of Leizhou black duck

This study investigated the factors that caused the differences in egg production during the development of ovarian follicles in Leizhou black ducks. Leizhou black ducks population was divided into 2 groups as high-yield group (HG) and low-yield group (LG). The number of eggs (NE), age at first egg (AFE), weight at first egg, and egg weight (EW) of both groups were recorded, and differences were analyzed using the t test. The logistic model was used to simulate the egg production curves to analyze the production rules. The ovarian follicles of both duck groups were collected to count the number of different grades sized follicles, weigh the ovaries, and observe follicular sections to analyze the developmental differences. Ovarian transcriptomic sequencing was performed to investigate differentially expressed genes and signal pathways in both duck groups. The results revealed a significant difference (P < 0.01) in the NE laid, AFE, and EW between both groups. Comparatively, HG had significantly more (P < 0.01) large yellow follicles (LYF) than LG. The density of medullary layer cells of the follicle section was greater in HG than LG ducks. Transcriptome sequencing revealed a total of 1,027 differentially expressed genes between the HG and LG ducks of which 495 genes were upregulated, and 532 genes were downregulated. Fifty genes were related to reproduction and reproductive processes. Kyoto Encyclopedia of Genes and Genomes–enriched signaling pathways revealed 274 signal pathways enriched in these differentially expressed genes of which the steroid biosynthesis pathway was significantly enriched. Analysis (Q < 0.05) showed that HSD3β → gonadotropin-releasing hormone (GnRH) and estrogen receptor (ESR) → LHβ/ERK1/2 were enriched in the steroid biosynthesis signal pathway. Follicle-stimulating hormone signal pathway mediated by HSD3β → GnRH and ESR → LHβ/ERK1/2 may be involved in ovarian follicle development to regulate LYF reserve process and affect its ovulation cycle, which in turn influence the egg production of Leizhou black ducks.

Effect of Different Percentage of Camelina sativa Cake in Laying Hens Diet: Performance, Welfare, and Eggshell Quality

Simple SummaryNowadays, it is of primary importance to find alternative and sustainable protein sources for animal feeding, taking into account environmental sustainability and animal welfare and production. Camelina sativa, as an alternative source of protein in animal feeding, seems to be a good candidate, but its use is limited by the presence of antinutritional compounds. In this study, a camelina breeding line with a low level of glucosinolates was tested for 31 weeks, in order to verify if the inclusion of up to 20% of camelina cake, in the diet of laying hens, could have an adverse effect on the production performance, eggshell quality, and animal welfare and health. Results demonstrated that the performance was maintained, as well as health and welfare, while eggshell quality slightly improved when hens got older.Although camelina [Camelina sativa (L.) Crantz] is a good source of protein, antioxidants, and polyunsaturated fatty acids, its antinutritional compounds limit its use in animal feeding. The aim of this study was to verify the effect of feeding laying hens with up to 20% of camelina cake from a breeding line containing a low level of glucosinolates on performance, welfare, and eggshell quality. Two hundred and forty Hy-Line® hens from 18 to 51 weeks of age were divided into three treatments: control (C), camelina cake 10% (CAM10), and camelina cake 20% (CAM20). Egg number was recorded daily, while egg weight, feed consumption, and mortality were recorded weekly. At 24 and 43 weeks of hen age, shell resistance to fracture was measured. Our results demonstrate no detrimental effects for CAM10 and CAM20 diets on feed intake, growth performance, and welfare. No difference in egg production was detected among the diets. The significant (p < 0.05) interaction of diet and age factors suggest that the addition of camelina cake, up to 20%, likely protects the eggshell of older hens. Our findings confirm that camelina cake might be an alternative and sustainable protein source for hens.

Effect of different diets on the growth and development of Harmonia axyridis (Pallas)

AbstractHarmonia axyridis (Pallas) is an important natural enemy of crop pests. Feeding H. axyridis through artificial diets (ADs) is an important means to achieve large‐scale production. In this study, the effects of different diets on the growth, development and reproduction of H. axyridis were comprehensively evaluated, and the reasons for the reduced reproductive capacity of H. axyridis fed ADs were preliminarily explored. Artificial diets were prepared using pig liver and pork as the main ingredients. Larval duration, larval survival rate, egg production and other traits were comprehensively evaluated. Harmonia axyridis fed ADs during both the larval and adult periods completed growth and development from larva to adult but had a prolonged development duration (6.13‐day extension) and reduced survival rate (15.3% reduction) in the larval stage. In addition, adults could not lay eggs. Next, individuals of H. axyridis were fed Megoura japonica (Matsumura) in the larval stage and an AD, adequate aphids (AA) or an artificial diet plus 5 (AD5), 10 (AD10) or 25 (AD25) aphids in the adult stage. The adults in the AD group produced a small number of eggs (103.3 eggs). When aphids were added to the diet, egg production gradually increased with the number of aphids added. The AD25 group exhibited no significant difference in egg production compared with that in the AA group (983.8 eggs and 1,158.3 eggs, respectively). Anatomical observations of the H. axyridis adults in these five groups revealed that ovary development was slowest in the AD group. In addition, we found that the levels of vitellogenin and juvenile hormone were significantly lower in the AD group than in the AA group. These results provide a foundation for formulating ADs for H. axyridis and improving the large‐scale reproduction of this species.