Egg Production Process Research Articles

Analisis Penerapan Target Coting Dalam Upaya Efisiensi Biaya Produksi Dan Peningkatan Laba Usaha Pada Usaha Kecil Menengah

UD. Adon Jaya which is located at Jl. Bima, Ds. Kebonsari RT 05 RW 01, Kec. Candi, Sidoarjo Regency, East Java is a Small and Medium Enterprise (UKM) owned by Pak Sulaiman which operates in the food sector, namely salted eggs. Salted eggs produced by UD. Adon Jaya has an interesting innovation where the salted eggs have different flavors and processing methods, such as original, fried, grilled and oven flavoured. Daily sales can reach 400 to 500 salted eggs with an income of IDR 16,000,000 to IDR 18,000,000 per month with a profit percentage of 31%. The research objective to be achieved in accordance with the research questions explained above is to find out, analyze and answer how the application of target costing affects production cost efficiency and increasing business profits at UD. Adon Jaya. This research took informants from UD owners. Adon Jaya, namely Mr Sulaiman and production employee Mas Zaky. In its implementation in the field, this research took secondary data including company history, financial and sales report data, as well as an explanation of the salted egg production process. The type of research that will be used is qualitative methods. The analysis technique used is comparative analysis between manual calculations used by UD. Adon Jaya with calculations that apply target costing carried out by the author. These results show that implementing target costing can streamline production costs by 12%, so that the resulting profit also increases 37%. The results of the analysis findings conclude that the application of target costing at UD. Adon Jaya has a positive influence by streamlining production costs so as to increase profits.

Inactivation of Salmonella enteritidis on the surface of eggs by air activated with gliding arc discharge plasma

Salmonella enteritidis, a Gram-negative foodborne pathogen, causes inflammation of the stomach and intestines. Poultry and poultry products are considered to be the main hosts of S. enteritidis, especially the most common edible eggs, and increase the risk of Salmonella infection. Therefore, developing the inactivation strategy of S. enteritidis on the surface of eggs is the key step during the egg production process. Gas plasma could effectively inactivate bacteria and fungi and is developed as a potential non-thermal sterilization method in the food industry. In this study, the plasma-activated air (PAA) prepared by the air activated with gliding arc discharge contained a variety of reactive species. When the PAA activated at the power of 50 W and 100 W was inducted into the incubation chamber, the numbers of S. enteritidis on egg fragments or the whole eggs were reduced below the detection limit. After PAA treatment, the eggshells exhibited no change in structure demonstrated by scanning electron microscope, the color of eggshells became a little decrease in red, the internal quality of both the raw egg and the cooked egg also exhibited no change, and trace reactive species remained in the albumen. Further, the PAA was also feasible for the batch treatment of stacked eggs. Therefore, this study supplied an effective and safe strategy for aseptic processing in the poultry industry.

Nutrient allocation to eggs in female Argentine shortfin squid, Illex argentinus using fatty acids as nutrient indicator

Fatty acids play a critical role in embryonic development of cephalopods. However, little information is available on the allocation of fatty acids to eggs during oogenesis, limiting our understanding regarding how these animals maximize reproductive performance in terms of energy and nutrient use. We explored the nutrients for egg production during maturation for Argentine shortfin squid ( Illex argentinus (Castellanos, 1960)) by comparing the fatty acid profiles between the ovary and eggs in the oviducts. We detected 30 fatty acids in the ovary and eggs, of which 19 constituted more than 0.2% of the total fatty acid content. The overall fatty acids in the ovary varied significantly among maturity stages, while the eggs had a consistent amount of total fatty acids and relative amount of individual fatty acids. There were consequently significant differences in the fatty acid profiles between the ovary and eggs by maturity stage and in total. Additionally, eggs had more saturated fatty acids but less polyunsaturated fatty acids than the ovary. Cumulatively, our results reveal that this squid produces eggs with consistent levels of nutrients virtually regardless of how the nutrient profile of the ovary varies during maturation, providing insight into the egg production process relation to nutrient allocation.

Transcriptomic analysis of the thyroid and ovarian stroma reveals key pathways and potential candidate genes associated with egg production in ducks

The importance of thyroid-related genes has been repeatedly mentioned in the transcriptome studies of poultry with different laying performance, yet there are few systematic studies to unravel the regulatory mechanisms of the thyroid-ovary axis in the poultry egg production process. In this study, we compared the transcriptome profiles in the thyroid and ovarian stroma between high egg production (GP) and low egg production (DP) ducks, and then revealed the pathways and candidate genes involved in the process. We identified 1,114 and 733 differentially expressed genes (DEGs) in the thyroid and ovarian stroma, separately. The Gene Ontology (GO) analysis showed that a total of 504 and 189 GO terms were identified in the thyroid and ovarian stroma (P < 0.05). Three common GO terms were identified from the top 5 GO terms with the highest significant level in two tissues, including extracellular space, calcium ion binding, and integral component of plasma membrane. The enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) showed that 15 and 14 KEGG pathways were significantly (P < 0.05) enriched in the thyroid and ovarian stroma, respectively. And, there were 8 common pathways, including neuroactive ligand-receptor interaction, calcium signaling pathway, ECM-receptor interaction, PPAR signaling pathway, melanogenesis, wnt signaling pathway, vascular smooth muscle contraction, and cytokine-cytokine receptor interaction. Notably, the neuroactive ligand-receptor interaction pathway was the most significantly enriched by the DEGs both in the thyroid and ovarian stroma. The interaction among DEGs enriched in the neuroactive ligand-receptor interaction and ECM-receptor interaction suggested that the thyroid may regulate ovarian development by these genes. Through integrated analysis of the protein-protein interaction (PPI) network and KEGG pathway maps, 9 key DEGs (PTH, THBS2, THBS4, CD36, ADIPOQ, ACSL6, PRKAA2, CRH, and PCK1) were identified, which could play crucial roles in the thyroid to regulate ovarian function and then affect egg-laying performance between GP and DP. This study serves as a basis to explore the molecular mechanism of the thyroid affecting ovarian function and egg production in female ducks and may help to identify molecular markers that can be used for duck genetic selection.

THE EFFECT OF ACARICIDAL DRUGS BASED ON HERBAL RAW MATERIAL ON THE FERTILITY OF IXODES RICINUS

Therefore, a problem of successful control of ixodes ticks occupies the important place in veterinary medicine and requires searching of new highly effective ascaricidic drugs. Modern synthetic acaricides has led to the environmental pollution problems and further development of resistance within the target tick populations. It really appeared to be the environmental problem. Taking into consideration this fact, the ixodes tick's population decreasing is one of the most important tasks of veterinary science and it requires searching for new environmentally friendly and highly effective acaricides. The aim of our study was to compare the effect of an acaricidal drug developed by us (based on thymol and citral with the addition of sage essential oil) with a synthetic chemical (based on cypermethrin 0.125%) on the fertility of females Ixodes ricinus. Our research showed that the components of the drug can affect the reproductive function of females of ixodes ticks by prolonging the time of egg formation by 3-4 days and reducing their productivity by 80.8% and lead to the death of females before they have completed the process of egg production. The development of environmentally friendly acaricides to limit the number of ectoparasitic arthropods is of practical importance and can give a new understanding of the possible use of essential oils as a part of acaricidal and repellent drugs with low impact on the environment, as well as on human and animal health.

Allocation of more reproductive resource to egg size rather than clutch size of gregarious desert locust (Schistocerca gregaria) through increasing oogenesis period and oosorption rate

The desert locust, Schistocerca gregaria, shows a density-dependent reproductive trade-off by laying fewer but larger eggs in crowded conditions (gregarious phase) than in isolated conditions (solitarious phase). However, the physiological mechanisms controlling reproductive resource allocation remain unclear. We examined how egg production processes, including ovulation timing (i.e., oogenesis period), oocyte and ovarian growth rates, and oosorption rate (resorbing developing terminal oocytes), regulate reproductive outputs (egg biomass per clutch, egg size, and clutch size) during a reproductive cycle in S. gregaria by rearing them either under isolated or crowded conditions. We observed a common density-dependent negative correlation between egg size and clutch size, with no significant difference in egg biomass between the two rearing conditions. Dissection of female locusts after different days of oviposition revealed that the daily oocyte growth rate was almost similar between the two rearing conditions, but crowd-reared females ovulated later than isolated-reared ones, resulting in further oocyte growth in the former. Terminal oocytes were renewed by previous penultimate oocytes at the onset of a new reproductive cycle, and oosorption mainly occurred at an early stage in both rearing conditions; however, crowd-reared locusts displayed higher levels of oosorption compared to their isolated-reared counterparts. Crowding induced a high oosorption rate, resulting in a reduced clutch size and a prolonged oogenesis period, which in turn allowed oocytes to intake more yolk, which was probably recycled via oosorption. These results suggest that the length of the oogenesis period and oosorption rate are manipulated by maternal density, and these physiological modifications interactively regulate reproductive trade-off in S. gregaria.

Molecular mimicry between SARS-CoV-2 and the female reproductive system.

IntroductionOogenesis, the process of egg production by the ovary, involves a complex differentiation program leading to the production of functional oocytes. This process comprises a sequential pathway of steps that are finely regulated. The question related to SARS‐CoV‐2 infection and fertility has been evoked for several reasons, including the mechanism of molecular mimicry, which may contribute to female infertility by leading to the generation of deleterious autoantibodies, possibly contributing to the onset of an autoimmune disease in infected patients.ObjectiveThe immunological potential of the peptides shared between SARS‐CoV‐2 spike glycoprotein and oogenesis‐related proteins; Thus we planned a systematic study to improve our understanding of the possible effects of SARS‐CoV‐2 infection on female fertility using the angle of molecular mimicry as a starting point.MethodsA library of 82 human proteins linked to oogenesis was assembled at random from UniProtKB database using oogenesis, uterine receptivity, decidualization, and placentation as a key words. For the analyses, an artificial polyprotein was built by joining the 82 a sequences of the oogenesis‐associated proteins. These were analyzed by searching the Immune Epitope DataBase for immunoreactive SARS‐CoV‐2 spike glycoprotein epitopes hosting the shared pentapeptides.ResultsSARS‐CoV‐2 spike glycoprotein was found to share 41 minimal immune determinants, that is, pentapeptides, with 27 human proteins that relate to oogenesis, uterine receptivity, decidualization, and placentation. All the shared pentapeptides that we identified, with the exception of four, are also present in SARS‐CoV‐2 spike glycoprotein–derived epitopes that have been experimentally validated as immunoreactive.

The Effect of Temperature on the Rate of Molybdenum Reduction by Enterobacter sp. strain Dr.Y13: Arrhenius Plot Analysis, Temperature Coefficient and Q10 Value Estimation

Molybdenum is a micronutrient that is needed a co-factor for many hydroxylation and redox transfer activities in animal and plant physiology. The greatest risk of overexposure is its ability to interfere with the sperm production and egg-production processes in a variety of species, including fish. It is only beginning to be used as a remediation technique for molybdenum-reducing bacteria. Temperature is one of the factors that influence molybdenum reduction. Many models may be used to predict the growth rate of microorganisms on different medium, depending on the temperature. The Arrhenius model is popular because it has few parameters. Temperature generally affects microbial growth and metabolic activity on their substrates. The small nature of microbes makes them susceptible to change in surrounding temperature. Growth on molybdenum by Enterobacter sp. strain Dr.Y13 is described, with a discontinuous chevron-like graph of apparent activation energy with a breakpoint at 32.66 oC. Regression analysis results suggest that in the lower temperature range of 20-30 oC, growth on molybdenum had an activation energy of 62.09 kJ/mol, whereas at the higher temperature range of 37–45 oC, it had an activation energy of 65.05 kJ/mol. For the examined temperature range (20-30 oC) and (37-45 oC), Q10 values of 2.32 and 2.21 and theta values of 1.09 and 1.08 were obtained, respectively. This is study is very useful in predicting the breakdown of molybdenum and the movement of molybdenum during bioremediation.

Avian Viruses that Impact Table Egg Production.

Simple SummaryGlobal table egg production is a multibillion-dollar industry. Poultry eggs provide an important source of protein, and consumers demand high-quality products. The industry relies on efficiency and good management, including vaccinations against the major poultry diseases, in order to ensure that they can match consumer demand. However, although there are a number of effective disease prevention protocols in place on poultry farms, viruses that affect egg production continue to be a major constraint for the sustainability of the table egg industry globally. Various factors related to either the infecting virus, the host, or the management system have been demonstrated to contribute significantly to the challenge for effective egg production. Viral infections in laying flocks have been shown to target various biological mechanisms that are essential for the quantitative and qualitative traits of egg production. This review describes the mechanisms involved in viral diseases of poultry that induce undesirable effects on egg production.Eggs are a common source of protein and other nutrient components for people worldwide. Commercial egg-laying birds encounter several challenges during the long production cycle. An efficient egg production process requires a healthy bird with a competent reproductive system. Several viral pathogens that can impact the bird’s health or induce reversible or irreversible lesions in the female reproductive organs adversely interfere with the egg industry. The negative effects exerted by viral diseases create a temporary or permanent decrease in egg production, in addition to the production of low-quality eggs. Several factors including, but not limited to, the age of the bird, and the infecting viral strain and part of reproductive system involved contribute to the form of reproductive disease encountered. Advanced methodologies have successfully elucidated some of the virus–host interactions relevant to the hen’s reproductive performance, however, this branch needs further research. This review discusses the major avian viral infections that have been reported to adversely affect egg productivity and quality and aims to summarize the current understanding of the mechanisms that underlie the observed negative effects.

Reducing Salmonella enterica serovar Enteritidis contamination in food: lytic bacteriophages in a homemade mayonnaise-like matrix

Background: Salmonella enterica serovar Enteritidis (SE) is one of the major causes of food-borne disease worldwide, mainly associated with the consumption of poultry products, such as eggs. Several control methods have been implemented in the egg production process, but they have not effectively reduced the outbreaks. Therefore, the use of bacteriophages for the biocontrol of food-borne pathogens is gaining increasing acceptance. Objective: To evaluate a bacteriophage cocktail's effectiveness in reducing SE counts in an experimentally contaminated mayonnaise-like matrix. Methods: Homemade mayonnaise was contaminated with SE (103 CFU/ml) with equal volume to a matrix (1:1) treated with a bacteriophage cocktail (five phages, MOI 105), and stored at 21 °C for 24 and 72 h. Bacterial counts were performed to evaluate the bio-controlling activity of the cocktail and compared with a contaminated but not treated group. Results: Significant reductions (up to 3.75 log10 CFU/ml) were observed in the bacteriophage-treated groups (p&lt;0.0001). Conclusions: These results demonstrate the effectiveness of bacteriophages as biocontrol agents for Salmonella Enteritidis in a raw-egg-derivative foodstuff. Further studies are needed to prove the reduction in an undiluted homemade mayonnaise.

ANALISIS PENGENDALIAN KUALITAS PRODUK TELUR ASIN PADA UD. SARI LUWIH DI DESA PADANG LUWIH

Good quality in the production process, with predetermined standards will minimize damaged products. The study was conducted at UD. Sari Luwih is a manufacturing and trading company that processes and sells salted egg products. This study aims to determine the quality control system of salted egg production processes at UD. Sari Luwih is optimal or not. Research is descriptive with a qualitative approach. The sampling method is by census technique. The data used in this study, is the data on the number of damaged salted egg products in the period from October to November 2019 with a sample of 37,500 eggs saturated. The analysis technique used is statistical quality control (SQC) using Check sheets, P-charts, Fishbone diagrams, and Quality cost. The results of the analysis using the P-chart show the amount of product damage that is beyond the control limits and requires more control, whereas for quality costs in 2019, the company's actual cost of quality is Rp. 21,210,696.89 is greater than the optimum quality cost where the cost is Rp. 17,389,652.10 shows that the cost of quality control has not yet reached the optimal level.&#x0D; Keywords: quality cost; quality; statistical quality control; SQC.

Fuzzy prediction and pattern analysis of poultry egg production

Egg production is geared towards large scale production of eggs for profit maximization and consumption. But poultry farmers are faced with challenges that affect the quantity and quality of egg production during the production life cycle such as quality of feed intake, management issues, genetic factors of the breed birds, age at egg laying period, presence of diseases, molting flock, housing and others. Several mechanical solutions have been suggested to implement the production cycle but with very high cost implication which calls for the need of soft computing methods to model the egg production process. However, modelling egg production curve is a complex task because a typical egg production curve (from week 20 to week 72) is characterized by nonlinear probabilities and imprecise knowledge in the egg production process. This paper proposes an optimal fuzzy predictive model for poultry egg production. The motivation stems from analyzing the non-linearity and imprecision in egg production which is best handled by fuzzy logic as compared to other soft computing techniques. Data samples were collected on the age of chicks, quantity of feeds, quality of feeds, body weight of chicks and total egg production as input into the proposed system. The first stage of implementation is carried out in the Statistical Package for Social Science (SPSS) software environment to perform correlation analysis while the last two stages are carried out using Fuzzy Toolbox in MATLAB based on its capability to model and simulate complex systems with robust and interpretable predictions. Gaussian membership function was used in the fuzzification process while Mamdami structure was adopted as the fuzzy inference system (FIS). Model performance evaluation showed that the proposed system performed excellently by achieving best prediction accuracy 100% Pred(30) with an approximate mean magnitude relative error (MMRE) of 0.11744 as compared to the results in the reported literature. The method has proven to be a cost-effective and simple approach to modelling through the use of samples and parameters from poultry house.

Efficacité technique des exploitations avicoles productrices d’œufs au sud du Bénin

Dans un contexte d’importation massive de produits avicoles au Bénin, la problématique relative à la performance des exploitations avicoles nationales est au cœur du débat. Afin d’assurer une meilleure allocation des ressources productives, des considérations d’ordre socioéconomiques entrent en jeu. Cette étude visait à établir le niveau de performance des exploitations de poules pondeuses au sud du Bénin. A travers l’approche paramétrique, les niveaux d’efficacité technique ont été estimés à partir d’une frontière stochastique de production. Les données ont été collectées auprès de quarante-cinq exploitations avicoles au moyen d’enquêtes réalisées entre août et septembre 2016. Les analyses ont montré que ces exploitations étaient en majorité performantes malgré des écarts d’efficacité entre elles. Le capital humain, le travail, les traitements vétérinaires étaient les principaux facteurs significatifs du processus de production d’œufs. La régression de la fonction de production a révélé que la faible production résultait davantage de l’insuffisance technique des producteurs (84 %) que de la répartition inefficace des ressources (16 %). Les écarts d’efficacité s’expliquaient par des facteurs socioéconomiques, notamment l’appui de l’Etat, le niveau d’instruction, l’âge de l’aviculteur, ses compétences et la densité des élevages. En conclusion, au Bénin les exploitations avicoles enquêtées étaient performantes mais restaient fragilisées par des externalités.

Synergistic effects of combined X-ray and aqueous chlorine dioxide treatments against Salmonella Typhimurium biofilm on quail egg shells

The current study investigated the synergistic effect of combined X-ray irradiation (0.5, 1.0, 1.5, and 2.0 kGy) and aqueous chlorine dioxide (ClO2) treatment (10, 20, 30, and 50 ppm) on Salmonella enterica serovar Typhimurium biofilms on the surfaces of quail egg shells. The synergistic effect was not dependent on the X-ray irradiation dose or ClO2 concentration. The synergistic reductions of biofilms after X-ray/ClO2 treatment on the egg shells were −0.1–1.1 log CFU/egg. The largest reduction was 1.1 log CFU/cm2 after a 2.0 kGy X-ray and a 20 ppm ClO2 treatment. No significant change (P > 0.05) was observed in the Hunter colors (L*, a*, and b*) and shear force (shell thickness) of the egg shell surfaces after single or combined treatments. Similarly, no significant changes (P > 0.05) were observed in the same parameters on the egg shell surfaces when a combination treatment of minimum X-ray doses/ClO2 concentrations and a combination treatment of maximum X-ray doses/ClO2 concentrations were applied separately. The results indicated that the combination treatment of 2.0 kGy X-ray/20 ppm ClO2 could be used in the egg production, processing, and distribution processes to enhance food safety without causing changes to the egg shell surface color and shell thickness.

Comparative transcriptomic analysis of high and low egg-producing duck ovaries

The egg-laying rate is an important indicator of egg production of laying ducks. Egg production directly impacts the economic benefits of the duck industry. In order to obtain better insight into the molecular mechanisms associated with the process of egg production, comparative transcriptomic analysis of the ovaries of Jinding ducks with high and low egg production was performed using the Illumina HiSeq 2500 system. A total of 843 differentially expressed genes (DEGs) was identified, 367 that were down-regulated and 476 that were up-regulated in high egg production (HEP) ovaries, as compared with low egg production (LEP) ovaries. Some genes, such as MC5R, APOD, ORAI1, and DYRK4, were more active in HEP ovaries, indicating that these genes may play important roles in regulation of egg production. Among these 843 DEGs, 685 were assigned to gene ontology (GO) categories. Of these, 25 genes were related to reproduction, and 30 were related to the reproductive process, including some associated with ovarian follicle development, circadian regulation of gene expression, circadian rhythm, and estrogen receptor binding. Furthermore, some important functional pathways were revealed, such as the steroid biosynthesis pathway, the endocrine and other factor-regulated calcium reabsorption pathways, circadian rhythm, the neuroactive ligand-receptor interaction pathway, fatty acid biosynthesis, and the calcium-signaling pathway, which appear to be much more active in the HEP group, as compared to those of the LEP group. The results of this study provide very useful information that may contribute to future functional studies of genes involved in bird reproduction.

Synergistic effect of a combination of ultraviolet–C irradiation and sodium hypochlorite to reduce Listeria monocytogenes biofilms on stainless steel and eggshell surfaces

The present study demonstrates the synergistic effect of treatment with a combination of ultraviolet (UV)C (300, 600, 1200, and 1800 mWs/cm2) irradiation and sodium hypochlorite (NaOCl) (50, 100, 150, and 200 ppm) on Listeria monocytogenes ATCC 19113 biofilms formed on stainless steel and eggshell surfaces. The synergistic effect was not dependent on the dose of UV–C irradiation or the concentration of NaOCl. Synergistic reductions of biofilms after UV–C/NaOCl treatment on stainless steel and eggshells were 0.95–3.68 log CFU/cm2 and –0.22 to 1.02 log CFU/cm2, respectively. The largest synergistic reductions of biofilms were 3.68 log CFU/cm2 using 1800 mWs/cm2 UV–C and 200 ppm NaOCl on stainless steel, and 1.02 CFU/cm2 using 600 mWs/cm2 UV–C and 50 ppm NaOCl on eggshells. The Hunter colors of L*, a*, and b* were not significantly (P > 0.05) changed on eggshell surfaces treated with all single and combined treatments. The results in this study indicate that the combination treatment of 1800 mWs/cm2 UV–C/200 ppm NaOCl could be feasible for use on stainless steel surfaces in industrial kitchens, facilities, and restaurants. In addition, the combination of 600 mWs/cm2 UV–C/500 ppm NaOCl could possibly be used in egg production, processing, and distribution processes to enhance food safety without causing changes to the eggshell surface color.

A leader–follower partially observed, multiobjective Markov game

The intent of this research is to generate a set of non-dominated finite-memory policies from which one of two agents (the leader) can select a most preferred policy to control a dynamic system that is also affected by the control decisions of the other agent (the follower). The problem is described by an infinite horizon total discounted reward, partially observed Markov game (POMG). For each candidate finite-memory leader policy, we assume the follower, fully aware of the leader policy, determines a (perfect memory) policy that optimizes the follower’s (scalar) criterion. The leader–follower assumption allows the POMG to be transformed into a specially structured, partially observed Markov decision process that we use to determine the follower’s best response policy for a given leader policy. We then approximate the follower’s policy by a finite-memory policy. Each agent’s policy assumes that the agent knows its current and recent state values, its recent actions, and the current and recent possibly inaccurate observations of the other agent’s state. For each leader/follower policy pair, we determine the values of the leader’s criteria. We use a multi-objective genetic algorithm to create the next generation of leader policies based on the values of the leader criteria for each leader/follower policy pair in the current generation. Based on this information for the final generation of policies, we determine the set of non-dominated leader policies. We present an example that illustrates how these results can be used to support a manager of a liquid egg production process (the leader) in selecting a sequence of actions to maximize expected process productivity while mitigating the risk due to an attacker (the follower) who seeks to contaminate the process with a chemical or biological toxin.

Changes in the number of eggs loaded in Pantala flavescens females with age from mass flights (Odonata: Libellulidae).

The wandering glider dragonfly Pantala flavescens migrates to Japan every spring, where the population increases until autumn, in which mass flights often occur, followed by death in the winter. There have been no reports to date on the maturation process of this species throughout its lifespan in Japan. We collected females from mass flights when the flight height was low, and classified them into seven age stages by examining their wing condition. Very few females of the older stage were collected from the mass flights. The wing condition corresponded with the change in body color and with the egg production process in the ovaries. While pre-reproductive-stage females did not release eggs when treated with our artificial oviposition technique, each reproductive-stage female released about 640 eggs. Nearly all eggs released were fertilized. The ovaries developed with the stage, and reproductive-stage females had about 1100 ovarioles. The estimated maximum fecundity was about 29,000 eggs. The lifetime number of eggs laid of P. flavescens should be revealed by dissection.

Food use is affected by the experience of nest predation: implications for indirect predator effects on clutch size

Indirect predator effects on prey demography include any effect not attributable to direct killing and can be mediated by perceived predation risk. Though perceived predation risk clearly affects foraging, few studies have yet demonstrated that it can chronically alter food intake to an extent that affects demography. Recent studies have used stable isotopes to gauge such chronic effects. We previously reported an indirect predator effect on the size of subsequent clutches laid by song sparrows (Melospiza melodia). Females that experienced frequent experimental nest predation laid smaller clutches and were in poorer physiological condition compared to females not subject to nest predation. Every female was provided with unlimited supplemental food that had a distinctive (13)C signature. Here, we report that frequent nest predation females had lower blood δ(13)C values, suggesting that the experience of nest predation caused them to eat less supplemental food. Females that ate less food gained less fat and were in poorer physiological condition, consistent with the effect on food use contributing to the indirect predator effect on clutch size. Tissue δ(15)N values corroborated that clutch size was not likely constrained by endogenous resources. Finally, we report that the process of egg production evidently affects egg δ(13)C values, and this may mask the source of nutrients to eggs. Our results indicate that perceived predation risk may impose food limitation on prey even where food is unlimited and such predator-induced food limitation ought to be added to direct killing when considering the total effect of predators on prey numbers.

Fatty Acid Oxidation Is Essential for Egg Production by the Parasitic Flatworm Schistosoma mansoni

Schistosomes, parasitic flatworms that cause the neglected tropical disease schistosomiasis, have been considered to have an entirely carbohydrate based metabolism, with glycolysis playing a dominant role in the adult parasites. However, we have discovered a close link between mitochondrial oxygen consumption by female schistosomes and their ability to produce eggs. We show that oxygen consumption rates (OCR) and egg production are significantly diminished by pharmacologic inhibition of carnitine palmitoyl transferase 1 (CPT1), which catalyzes a rate limiting step in fatty acid β-oxidation (FAO) and by genetic loss of function of acyl CoA synthetase, which complexes with CPT1 and activates long chain FA for use in FAO, and of acyl CoA dehydrogenase, which catalyzes the first step in FAO within mitochondria. Declines in OCR and egg production correlate with changes in a network of lipid droplets within cells in a specialized reproductive organ, the vitellarium. Our data point to the importance of regulated lipid stores and FAO for the compartmentalized process of egg production in schistosomes.