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Background: The development and egg-laying performance of hens are precisely regulated by hormones secreted by the pituitary. In this study, we performed comprehensive transcriptome sequencing of pituitary from Hy-Line Brown hens at 15, 20, 30 and 68 W of age. Through association analysis, we identified key genes and ceRNA regulatory networks related to pituitary development and egg production. Results: Based on the comprehensive transcriptome data, we identified 470 differentially expressed lncRNAs (DE-lncRNAs), 38 differentially expressed miRNAs (DE-miRNAs), and 2,449 differentially expressed mRNAs (DE-mRNAs). Time-series analysis pinpointed genes and signaling pathways that significantly influence pituitary hormone secretion at various stages. At 15 W, the high expression of GHRHR, NPY1R, and TSHR in the pituitary supports growth. At 20 and 30 W, elevated GNRHR expression sustains continuous egg production. In the late laying period, the expression of PRL may lead to a decline in egg production. Additionally, association analysis enabled the construction of a ceRNA regulatory network involving non-coding RNAs that regulate the development and reproduction of hens. Conclusion: This study elucidated the comprehensive transcriptome expression profiles of the pituitary gland during the development and egg-laying processes in Hy-Line Brown hens and constructed the associated molecular regulatory networks. These findings lay the foundation for investigating the mechanisms by which non-coding RNAs regulate pituitary hormone secretion. [ABSTRACT FROM AUTHOR]

Neural communication requires both fast-acting neurotransmitters and neuromodulators that function on slower timescales to communicate. Endogenous bioactive peptides, often called "neuropeptides," comprise the largest and most diverse class of neuromodulators that mediate crosstalk between the brain and peripheral tissues to regulate physiology and behaviors conserved across the animal kingdom. Neuropeptide signaling can be terminated through receptor binding and internalization or degradation by extracellular enzymes called neuropeptidases. Inactivation by neuropeptidases can shape the dynamics of signaling in vivo by specifying both the duration of signaling and the anatomic path neuropeptides can travel before they are degraded. For most neuropeptides, the identity of the relevant inactivating peptidase(s) is unknown. Here, we established a screening platform in C. elegans utilizing mass spectrometry-based peptidomics to discover neuropeptidases and simultaneously profile the in vivo specificity of these enzymes against each of more than 250 endogenous peptides. We identified NEP-2, a worm ortholog of the mammalian peptidase neprilysin-2, and demonstrated that it regulates specific neuropeptides, including those in the egg-laying circuit. We found that NEP-2 is required in muscle cells to regulate signals from neurons to modulate both behavior and health in the reproductive system. Taken together, our results demonstrate that peptidases, which are an important node of regulation in neuropeptide signaling, affect the dynamics of signaling to impact behavior, physiology, and aging. [Display omitted] • Neuropeptidomic screen identified a neuropeptidase, NEP-2, and its targets • NEP-2 regulates NLP-3 neuropeptides to modulate egg-laying behavior • Expression of nep-2 in muscle, and not neurons, is required for proper egg laying • Targeting NEP-2 in animals with compromised egg-laying (matricide) improves health Neuropeptidases are an important and understudied node of regulation in peptidergic circuits. Lo et al. use neuropeptidomics to identify NEP-2 as a neuropeptidase in C. elegans and simultaneously link it to endogenous peptide targets. They demonstrate how NEP-2 regulates the dynamics of peptidergic signaling to impact behavior and aging. [ABSTRACT FROM AUTHOR]

Constraints to Guinea fowl (Numida meleagris) production include poor growth and low laying performance. However, the lack of standard nutritional requirements significantly hinders commercial indigenous Guinea fowl production in Nigeria. This study aimed to determine the proper levels of crude protein (14, 16, and 18%) and metabolizable energy (2.65, 2.75, and 2.85 Mcal/kg) in the diets of native Guinea fowl in Nigeria. The dietary protein (PL) and energy (EL) levels for the fowl were evaluated in a completely randomized 3 (PL) × 3 (EL) factorial design with three replicates of 10 birds each. Thus, 270 birds with 20 weeks of age were allocated randomly to nine dietary treatments (18P:2.65E, 18P:2.75E, 18P:2.85E, 16P:2.65E, 16P:2.75E, 16P:2.85E, 14P:2.65E, 14P:2.75E and 14P:2.85E). The PL × EL interaction affected Guinea fowl's DFI, DWG, and WWG (p<0.05), while WFI and FCR remained unaffected. The 16:2.85E diet increased the DFI of the birds compared to other diets (p˂0.05). The DFI of the 18:2.65, 18:2.75, and 16:2.75E Guinea fowls was higher than those of 18:2.85E, 14:2.65E, 14:2.75E, and 14:2.85 birds (p˂0.05). The DWG of fowls improved by the 16:2.85E diet compared to other diets, except for the 18P:2.65E and 16P:2.75E diets (p˂0.05). The interaction had a significant impact on the EN, EYH, and EM of the Guinea fowl egg while FCR remained unaffected. The 18P:2.85E diet improved the EN and EM of the birds compared to other diets (p˂0.05), The 18P:2.85E also improved the FCR for laying except for 14P:2.85E and 18P:2.75E. The 18P:2.85E diet influenced the YW of the birds compared to other diets (p˂0.05), whereas the EW of fowls improved by the 16:2.85E diet compared to other diets except for the 16P:2.65E diet (p˂0.05). In conclusion, feeding guinea fowls with a diet comprising 18% protein and 2.85 Mcal/kg metabolizable energy significantly improved egg production and quality [ABSTRACT FROM AUTHOR]

Abstract Background The development and egg-laying performance of hens are precisely regulated by hormones secreted by the pituitary. In this study, we performed comprehensive transcriptome sequencing of pituitary from Hy-Line Brown hens at 15, 20, 30 and 68 W of age. Through association analysis, we identified key genes and ceRNA regulatory networks related to pituitary development and egg production. Results Based on the comprehensive transcriptome data, we identified 470 differentially expressed lncRNAs (DE-lncRNAs), 38 differentially expressed miRNAs (DE-miRNAs), and 2,449 differentially expressed mRNAs (DE-mRNAs). Time-series analysis pinpointed genes and signaling pathways that significantly influence pituitary hormone secretion at various stages. At 15 W, the high expression of GHRHR, NPY1R, and TSHR in the pituitary supports growth. At 20 and 30 W, elevated GNRHR expression sustains continuous egg production. In the late laying period, the expression of PRL may lead to a decline in egg production. Additionally, association analysis enabled the construction of a ceRNA regulatory network involving non-coding RNAs that regulate the development and reproduction of hens. Conclusion This study elucidated the comprehensive transcriptome expression profiles of the pituitary gland during the development and egg-laying processes in Hy-Line Brown hens and constructed the associated molecular regulatory networks. These findings lay the foundation for investigating the mechanisms by which non-coding RNAs regulate pituitary hormone secretion.

The studies of the mountain cicada population have been conducted on M. Sandyreva and its surroundings (“Russian North” National Park) since 2019. The results of observations (2022) include the date of fixation of first exuviae of the mountain cicada larva and first imago appearance, as well as detected damage of such woody plants as an apple, a rosehip , a mountain ash, a brittle buckthorn, a honeysuckle, a juniper, and a raspberry. The plants were damaged presumably by ovipositor of the mountain cicada. The authors have collected the information on a damages size and their location on shoots, described the appearance, and specified a height of damaged plants. The data obtained was compared with the related scanty information present in the open sources.

Egg production is a significant source of animal protein for human consumption. Feed costs significantly impact the profitability of egg production, representing more than 70% of the variable costs. This study evaluated the effect of dietary intakes of three essential amino acids (EAAs) on the egg cost for H&N Brown second-cycle laying hens. The hens were fed for 20 weeks with 23 diets that varied in their lysine, methionine + cystine, and threonine contents. These amino acids were derived from both dietary and synthetic sources. Zootechnical results were used to calculate the feed cost per kilogram of egg (FCK), considering the cost of raw materials and the diet composition. Multivariate polynomial models and artificial neural networks (ANNs) were validated to predict FCK as a function of the EAAs and time. The EAA intakes that minimize FCK over time were optimized using the best model, a cascade-forward ANN with a softmax transfer function. The optimal scenario for FCK (0.873 USD/kg egg) at 20 weeks was achieved at 943.7 mg lysine/hen-day, 858.3 mg methionine + cystine/hen-day, and 876.8 mg threonine/hen-day. ANNs could be a valuable tool for predicting the egg cost of laying hens based on the nutritional requirements. This could help improve economic efficiency and reduce the feed costs in poultry companies. [ABSTRACT FROM AUTHOR]

Habitat selection of Culicoides spp. (Diptera: Ceratopogonidae) is influenced by the physicochemical factors such as temperature, pH, salinity, moisture, conductivity, organic and inorganic compounds of substrates. These factors determine the life history traits of the vectors. We studied the influence of substrate salinity (0–40 parts per thousand, ppt) and pH (pH 1–13) on oviposition, egg hatching, larval survivability, and adult emergence of Culicoides peregrinus Kieffer under laboratory conditions. Most eggs (80.74%) were laid in 0 ppt and 95% in pH 7 but lowered with increased salinity and pH levels. It was observed that the females did not lay eggs in 30 ppt to 40 ppt salinity; pH 1 and pH 13 but interestingly up to 95% of the eggs were retained within the abdomen. Little effect of salinity and pH on egg hatching was observed up to 5 ppt and 10 ppt except at the extreme values of 40 ppt and pH 1, pH 13. Pupation did not occur in rearing plates with high salinities, 30 ppt and 40 ppt, although the few eggs hatched when exposed to such salinity. In low salinity (0 to 2 ppt), occurrence of adult emergence was more and then decreased with increasing salinity. Maximum emergence was seen when the rearing media was alkaline. This study deals with the suitability of breeding substrate of C. peregrinus when exposed to salinity and pH ranges. Our study suggests the ambient salinity and pH ranges to be maintained during laboratory rearing of this vector species. [ABSTRACT FROM AUTHOR]

Pink bollworm (PBW), Pectinophora gossypiella is one of the major pests of cultivated cotton around the globe. Most of the attempts to control this pest by using chemical insecticides in crops have led to the evolution of numerous problems. Hence a suitable tool that addresses the problem will be a plausible way to manage the pest. The use of natural enemies may represent an effective alternative management tactic. Here, we study the parasitization potential of Bracon hebetor on different larval instars of P. gossypiella under laboratory condition. The release of B. hebetor at 30:50 (PBW larvae: parasitoid) and 30:40 ratios resulted in significantly higher level of parasitization on PBW larvae (85.8–94.2% in 2nd instar, 99.2–100% in 3rd instar and 100% in 4th instar of PBW) than with 30:30, 30:20 or 30:10 (PBW larvae: parasitoid) ratio (40.0–63.3% in 2nd instar, 47.5–78.3% in 3rd instar and 50.8–80.8% in 4th instar of PBW), respectively. Similarly, the survival of B. hebetor eggs demonstrated positive results, with up to 89.2% of parasitoid adults emerging from second-instar larvae when released in a ratio of 30:10. Additionally, on fourth-instar larvae, parasitoid emergence rates of 93.7% and 93.9% were observed for ratios of 30:10 and 30:20, respectively. This data indicates the host's suitability and the parasitoids high survivability. Lower number of eggs per larva was found to support a better survival of the parasitoid, with eggs ranging from 3.1 to 12.8 eggs per larvae and emergence of 7.9 to 93.9% at different ratios on all instars of PBW. The outcome of the present investigation is promising and suggests the parasitization and survival of B. hebetor is sufficient enough to manage the pest under controlled conditions and it is possibly an excellent candidate for augmentative biological control of PBW under field condition. [ABSTRACT FROM AUTHOR]

Loss of homeostasis and poor egg production are common in laying hens during hot season. These negative effects of extreme ambient temperature have resulted in great economic losses to poultry farmers in the tropical regions. This study investigate d benefits of supplementing watermelon juice (WJ) and ascorbic acid (AA) to ISA Brown (IB) hens managed under hot climate on productive performance and some hormonal responses. Ninety-six IB pullets aged 34 weeks were randomly allotted to four groups (C, T1, T2, and T3), each containing 24 in triplicates. The control group (C) was given water with neither WJ nor AA. Water given to groups T1, T2 was supplemented with 20% and 40% WJ, respectively, while T3 was supplemented with 200mg AA/litre of water. The results show a significant (P ≤ 0.05) increase in water intake in T3 compared to other groups. Total egg production, daily egg production and hen-day egg production were significantly (P ≤ 0.05) improved by the supplements, as total egg weights improved in T1:(272.2 ± 35.16g) and T2:(272.1 ± 35.06g) compared to C:(212.2 ± 25.06g) and T3:(238.5 ± 19.23g). The supplements caused 24.46%, 22.70% and 9.43% rise in percentage egg production in groups T1, T2, and T3 respectively. Serum corticosterone (C:10.88 ± 1.12; T1:10.20 ± 1.06; T2:9.61 ± 0.792; T3:7.23 ± 2.36ng/mL) and thyroxine levels (C:1.45 ± 0.562; T1:0.41 ± 0.109; T2:0.39 ± 0.367; T3:0.60 ± 0.489μg/dL) decreased significantly (P ≤ 0.05) in supplemented layers, while serum prolactin and triiodothyronine differed non-statistically. In conclusion, WJ and AA supplementation ameliorated heat stress in IB layers managed under hot climate as it significantly lowered corticosterone and improved egg production. Therefore, supplementing 20%, 40%WJ or 200mg AA/litre in water is recommended for managing heat stress in IB layer chickens. [ABSTRACT FROM AUTHOR]

Egg production is a significant source of animal protein for human consumption. Feed costs significantly impact the profitability of egg production, representing more than 70% of the variable costs. This study evaluated the effect of dietary intakes of three essential amino acids (EAAs) on the egg cost for H&N Brown second-cycle laying hens. The hens were fed for 20 weeks with 23 diets that varied in their lysine, methionine + cystine, and threonine contents. These amino acids were derived from both dietary and synthetic sources. Zootechnical results were used to calculate the feed cost per kilogram of egg (FCK), considering the cost of raw materials and the diet composition. Multivariate polynomial models and artificial neural networks (ANNs) were validated to predict FCK as a function of the EAAs and time. The EAA intakes that minimize FCK over time were optimized using the best model, a cascade-forward ANN with a softmax transfer function. The optimal scenario for FCK (0.873 USD/kg egg) at 20 weeks was achieved at 943.7 mg lysine/hen-day, 858.3 mg methionine + cystine/hen-day, and 876.8 mg threonine/hen-day. ANNs could be a valuable tool for predicting the egg cost of laying hens based on the nutritional requirements. This could help improve economic efficiency and reduce the feed costs in poultry companies.

ABSTRACT: Dietary metabolizable energy (ME) level could offer a well production performance through maintaining lipid homeostasis in poultry. In this study, a total of 540 geese (450 females and 90 males) at 64 wk of age with similar body weight (4,600 ± 382) were randomly divided into 5 groups with 3 replicates in each group and 30 females and 6 males (1♂:5♀) in each replicate. After 2 wk adaptation, the 5 groups were designed to provide diet with ME intakes of 9.65, 10.05, 10.70, 11.45, and 11.75 MJ/kg, respectively, according to production requirement. Body weight, egg production, hatchability, blood lipid, and fat deposition were recorded after 6 wk feeding. The expression of lipid synthesis-related genes, lipoprotein lipase (LPL) and fatty acid synthase (FASN), were determined by quantitative real-time PCR. Geese fed with high ME diet of 11.75 MJ/kg caused an increased liver and abdominal fat weight and low hatchability of set eggs. The ovarian weight and oviduct length were higher in geese fed dietary energy of 10.7 MJ/kg as compared to the 9.65 MJ/kg groups, whereas no significant difference was observed in geese fed dietary energy of 10.05 MJ/kg. Dietary energy level did not change the concentration of serum lipids at the late egg laying stage. The LPL expression exhibited linear and quadratic effect in response to dietary ME. The FASN expression showed quadratic effect and a relatively higher expression was exhibited in 10.05 and 11.45 MJ/kg than that of the 9.65 and 10.70 MJ/kg ME groups. According to the productivity, reproductive performance, and fat deposition, dietary ME of 10.13 to 10.28 MJ/kg could be suggested for breeding geese at their late laying stage.

Annexin A2 (ANXA2) is a member of the A subfamily of a multifunctional calcium dependent membrane phospholipid binding protein family. The mRNA expression of ANXA2 is consistent with ovary function and egg laying in chickens. In this study, six nucleotide polymorphisms in the key promoter region of chicken ANXA2 gene (−2861 bp to −1394 bp), i.e.,: g.−2337 indel (GT), g.−2255 C > T, g. −2248 A > G, g.−2188 A > G, g.−2169 G > A, g.−2160 A > C, were identified. Their distributions in populations of Xinyang Brown, Recessive White Rock, Wenchang and Wenshang Barred chickens were analyzed. In the Recessive White Rock chicken population, CAA, CAG and TGG were three major haplotypes. Association analysis indicated that the individuals with diplotype TGG/TGG laid more eggs at 32 weeks, and the individual with diplotype CAG/TGG laid at the earlier age. Luciferase activity assay showed that mutation from C to T at −2255 increased trascriptional activity of chicken ANXA2, which is consistent with its effect on egg laying traits. [ABSTRACT FROM AUTHOR]

The purpose of this study is to describe the reproductive processes of the snails Helix lucorum and Eobania vermiculata, which are abundant in Diyarbakır, SE Turkey. Reproductive behaviours and eggs of E. vermiculata and H. lucorum were monitored in the gardens of the Commodity Exchange Building, and Hevsel Gardens. The habitats of the species were observed over a one-year period (2022–2023). Helix lucorum reproduction takes place at the age of three to four years, from late October to December. The weight of the adult snails was 22 ± 4 g. The snails laid an average of 82 ± 12 eggs, with a weight of 0.23 ± 0.03 mg, and diameter of 5 mm; they hatched in 30 ± 4 days. Eobania vermiculata reproduction takes place at the age of two years, and breeding is mainly from early October to early December. The adult snails weighed 12 ± 4 g, and laid an average of 70 ± 14 eggs, with each egg weighing 0.16 ± 0.04 mg and measuring 3 mm in diameter. They hatched in 32 ± 5 days. In summary, the study offers details on the reproductive processes of two commercially significant snails, whose breeding habits may vary based on local climatic conditions. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of dietary supplementation with Glycyrrhiza polysaccharide (GCP) on growth performance, serum biochemistry, immunity, and egg laying in female quail. 300 1-day-old female quail were sorted into four dietary treatments with five replicate cages of 15 birds each. The basic diet in the four treatment groups was supplemented with 0, 500, 1000 and 1500 mg/kg GCP, and the experiment continued for 80 days. Results showed that dietary supplementation with GCP significantly (p < 0.05) increased average daily gain in a dose-dependent fashion, and decreased (p < 0.05) the feed-to-gain ratio and mortality. The relative weights of the thymus and bursa of Fabricius increased (p < 0.05) linearly with increasing dose of GCP from 0 to 1500 mg/kg on day 20. GCP birds showed higher serum levels of protein, glucose, immunoglobulin A and immunoglobulin M, but lower serum triglycerides (p < 0.05) on day 50. GCP increased (p < 0.05) average laying rate and average egg weight linearly from days 60 to 80, whereas feed to egg ratio was decreased (p < 0.05). Taken together, these results revealed that GCP could improve growth performance, serum biochemistry, immunity, and egg laying in female quail. Therefore, GCP may be a potential replacement for antibiotic growth promoters in poultry. [ABSTRACT FROM AUTHOR]

The CRISPR/Cas9 technology has opened up newer avenues in insect pest management like precision guided sterile insect technique (pgSIT) which achieves a highly specific mutation in the target genes such as spermatogenesis, sex determination related genes etc. In this regard, validating the loss-of-function of the target gene/s is a prerequisite before the final application. This is easily achieved through DNA-free editing by embryonic delivery of the cognate ribo nucleo protein complex (RNP) into G0 stage eggs. Obtaining uniform G0 stage eggs is necessary to offset the microinjection injury and have high heritability of the genomic edits. We to optimized a method to obtain intact eggs of Oriental fruit fly, Bactrocera dorsalis (Hendel) without injury for microinjection by modifying the oviposition behaviour of the gravid female of B. dorsalis to retrieve intact eggs and to obtain large number of G0 eggs for genome editing. This paper describes a method to obtain required number of eggs for such studies. Out of two egg laying methods, the one with a small container with water covered with parafilm and topped with a thin banana pulp slice provided intact eggs. Maximum oviposition was observed between 20-60 days after eclosion. By the present finding we can obtain sufficient eggs for microinjection at 15-minute interval. [ABSTRACT FROM AUTHOR]

Biology of the invasive species Pochazia shantungensis (Chou & Lu, 1977), already detected in the Western Palaearctic in 1977, is studied in two areas of Istanbul, Türkiye, on both sides of the Bosphorus. The species overwinters at the egg stage and has two generations per year. The number of host plants identified in this study is 57 (belonging to 31 families). With previous studies, the number of host plant species in Türkiye has reached 58. The main host plants were Ligustrum lucidum W. T. Aiton and Olea europaea L. Eggs are laid in double rows in the thin twigs of shrubs or trees of one-year old, exceptionally in the main vein on the lower leaf surface of Magnolia grandiflora L. The mean number of eggs laid on L. lucidum and O. europaea were 31.88 and 21.80, respectively. Mean length of egg masses was 17.90 and 15.36 mm and mean twig thickness was 2.21 and 2.20 mm, respectively, on L. lucidum and O. europaea. Zelus renardii (Hemiptera: Reduviidae) was identified as a predator of P. shantungensis. [ABSTRACT FROM AUTHOR]

Ceratitis capitata (Wiedemann), also known as the Mediterranean fruit fly, is one of the most serious pests for several fresh fruit commodities causing extensive fruit losses worldwide. The response of C. capitata adults to fruit and nonfruit volatiles has been extensively studied. However, the linkage between fruit volatiles and the female ovipositional choice has not been fully elucidated. The present study focused on identifying the volatile organic compounds emitted by detached intact fresh fruits (oranges, lemons, bergamots, and apples) and citrus essential oils and evaluate their effect on Mediterranean fruit fly oviposition. There were more than 130 and 45 volatiles compounds detected in fruits odors and citrus essential oils, respectively. The volatile profile of fruits was dominated either from terpenes and terpenoids or from esters of butanoic, hexanoic, and octanoic acids while limonene was by far the most abundant compound in all citrus essential oils. Oviposition of C. capitata was strongly affected by volatiles emanated from both intact fruit and the citrus essential oils. Regarding the volatiles of the intact fruits, the odor of sweet orange elicited strong oviposition responses to females, while bergamot had the least stimulatory effect on oviposition. Bergamot oil also elicited the least oviposition stimulation compared to sweet orange and lemon essential oils. Our discussion elaborates on the role of fruit volatiles on host finding behavior and fruit susceptibility to C. capitata infestation and includes possible practical implication of the above findings. [ABSTRACT FROM AUTHOR]

The broadbean seed beetle (Bruchus rufimanus Boheman, 1833) is a major pest of faba bean (Vicia faba L.) almost everywhere this crop is grown. The main tasks of this research were to study the seed beetle's phenology, and rates of egg laying, larval survival and the emergence of young adults before the harvest. Studies were done in field conditions in farms located in various places in Latvia. The highest density of imagines was observed at a time when the plants were flowering intensively. Egg laying began as soon as the pods had formed in the lower third of the stem and lasted 4–5 weeks. In severe infestation happened, more than 34 eggs were laid per pod. The percentage of damaged yield increased in proportion to the average number of eggs laid on pods until this number reached 11–12 eggs per pod and remained at approximately the same level also when egg-laying rate was higher. In several fields, no seeds with imago exit holes were found in the samples few days before harvest, while in other sowings, the proportion of such seeds exceeded 90% of the total amount of damaged yield.

Prey respond to predators by altering their behavior to optimize their own fitness and survival. Specifically, prey are known to avoid predator-occupied territories to reduce their risk of harm or injury to themselves and their progeny. We probe the interactions between Caenorhabditis elegans and its naturally cohabiting predator Pristionchus uniformis to reveal the pathways driving changes in prey behavior. While C. elegans prefers to lay its eggs on a bacteria food lawn, the presence of a predator inside a lawn induces C. elegans to lay more eggs away from that lawn. We confirm that this change in egg laying is in response to bites from predators, rather than to predatory secretions. Moreover, predator-exposed prey continue to lay their eggs away from the dense lawn even after the predator is removed, indicating a form of learning. Next, we find that mutants in dopamine synthesis significantly reduce egg laying behavior off the lawn in both predator-free and predator-inhabited lawns, which we can rescue by transgenic complementation or supplementation with exogenous dopamine. Moreover, we find that dopamine is likely released from multiple dopaminergic neurons and requires combinations of both D1- (DOP-1) and D2-like (DOP-2 and DOP-3) dopamine receptors to alter predator-induced egg laying behavior, whereas other combinations modify baseline levels of egg laying behavior. Together, we show that dopamine signaling can alter both predator-free and predator-induced foraging strategies, suggesting a role for this pathway in defensive behaviors.

The detailed reproductive physiology of cockatoos based on gonadal hormone dynamics is unclear. In this study, we aimed to investigate ovarian activity by monitoring urofecal sex steroid hormone profiles in a captive female white cockatoo (Cacatua alba) and to noninvasively reveal basic reproductive physiology by comparing the hormone profiles with the laying dates, body mass changes, and molt progress. Urofeces were collected regularly for approximately 4 years from one female that frequently laid unfertilized eggs under single-rearing conditions. Urofecal progesterone (P4) and estradiol-17ß (E2) were measured by enzyme immunoassay. In addition, body mass and the number of fallen feathers were measured periodically. The urofecal P4 concentration peaked at an average of 17.7 days after the start of the rise in urofecal E2 concentration, and egg laying began on the day after the peak urofecal P4 concentration. The clutch size was usually two eggs, with an average interval of 4.5 days between eggs in each egg-laying cycle. There was a significant correlation between the dynamics of E2 concentration in urofeces and body mass. The results strongly suggest that E2 and P4 reflect the follicle growth and ovulation status, respectively, and that noninvasive monitoring of hormone dynamics using urofeces can accurately capture ovarian activity in the white cockatoo. Furthermore, changes in body mass can predict follicular growth, and reproduction and molt are antagonistic. [ABSTRACT FROM AUTHOR]

Honey bee queens show extreme fecundity, commonly laying more than a thousand eggs in a single day. It has proven challenging to study the temporal organization of egg-laying behavior because queens are typically active around the clock in the dark cavity of a densely populated nest. To contend with this challenge, we developed two novel methods allowing detailed monitoring of queen activity and egg laying. We first adapted a high-resolution, continuous, tracking system allowing to track the position of barcode-tagged queens in observation hives with colonies foraging outside. We found that the queen is active ~96% of the day with typically no diurnal rhythm. Next, we developed a new laboratory procedure to monitor egg laying at single egg resolution under different light regimes. We found that under constant darkness (DD) and temperature conditions, queens laid eggs with no circadian rhythms. Queen fecundity was severely reduced under constant light (LL). Under a 12:12 illumination regime, queen fecundity was comparable to under constant darkness, with a higher number of eggs during the light phase. These daily rhythms in egg laying continued when these queens were released to DD conditions, suggesting that egg-laying rhythms are influenced by endogenous circadian clocks. These results suggest that honey bee queens are active and lay eggs around the clock with no diurnal rhythms. Light has complex influences on these behaviors, but more studies are needed to determine whether these effects reflect the influence of light directly on the queen or indirectly by affecting workers that interact with the queen. [ABSTRACT FROM AUTHOR]

Transmembrane channel-like (TMC) proteins are expressed throughout the animal kingdom and are thought to encode components of ion channels. Mammals express eight TMCs (mTMC1–8), two of which (mTMC1 and mTMC2) are subunits of mechanotransduction channels. C. elegans expresses two TMCs (TMC-1 and TMC-2), which mediate mechanosensation, egg laying, and alkaline sensing. The mechanisms by which nematode TMCs contribute to such diverse physiological processes and their functional relationship to mammalian mTMCs is unclear. Here, we show that association with accessory proteins tunes nematode TMC-1 to divergent sensory functions. In addition, distinct TMC-1 domains enable touch and alkaline sensing. Strikingly, these domains are segregated in mammals between mTMC1 and mTMC3. Consistent with these findings, mammalian mTMC1 can mediate mechanosensation in nematodes, while mTMC3 can mediate alkaline sensation. We conclude that sequence diversification and association with accessory proteins has led to the emergence of TMC protein complexes with diverse properties and physiological functions. [Display omitted] • Accessory proteins tune TMC-1 to different sensory functions • Distinct TMC1 domains mediate mechanosensation and alkaline sensing • Mammalian TMC-1 supports mechanosensation in nematodes • Mammalian TMC-3 supports alkaline sensing in nematodes Jiang et al. demonstrate that combinations of different accessory proteins tune nematode TMC-1 to different sensory functions. In addition, distinct structural domains of nematode TMC-1 mediate mechanosensation and alkaline sensing. These domains are segregated between mammalian mTMC1 and mTMC3, and mTMC1 supports mechanosensation in nematodes, while mTMC3 supports alkaline sensing. [ABSTRACT FROM AUTHOR]

This research aimed to use individual containers within a recirculating aquaculture system to induce ovarian maturation in female mantis shrimp (Harpiosquilla raphidea) broodstock. Forty-one female H. raphidea were cultured in individual containers at a density of one mantis shrimp/0.2 m2/container for 60 days. Seawater in the circulating system was replaced at a rate of 10% per day. The survival rate of female H. raphidea was 63% with an absolute growth rate of 0.210 ± 0.15 g day−1. Ovarian development was classified into six stages by monitoring changes in the external appearance (i.e., telson color and semen appearance), the color of the ovaries, the pattern of oocytes, and the gonadosomatic index (GSI). Stage 1 was classified by white ovaries (32.32 ± 7.72 µm in diameter; N = 11); stage 2 was classified by ovaries that appeared a cloudy white color (99.29 ± 21.01 µm in diameter; N = 6). Stage 3 was classified by light-yellow ovaries (105.23 ± 22.09 µm in diameter; N = 4). Stage 4 ovaries were a yellow/orange color (106.50 ± 27.70 µm in diameter; N = 11). Stage 5 had orange ovaries (162.11 ± 50.39 µm of diameter; N = 5) and stage 6 had dark orange ovaries (179.89 ± 27.41 µm of diameter; N = 4). Histological analysis also revealed six staged of oocyte developmental in H. raphidea, including early previtellogenic, late previtellogenic, early vitellogenic, late vitellogenic, maturation, and pre-spawn stages. The Lightness values (L*) of the ventral telson with the fused ovary were significantly higher in female H. raphidea broodstock in stages V and VI of ovarian development (p

A season-independent juvenile supply system is required for developing the aquaculture of the red swamp crayfish Procambarus clarkii. The present study aimed to test if P. clarkii females can spawn multiple times under a constant temperature (25°C) and photoperiod (14 L: 10D) – conditions that are suitable for their reproduction. When a female developed glair glands on the underside of its uropods, it was paired with a single male for mating. Females that laid the first egg batch from the middle of July to the end of October were successively cultured; large proportions of individuals then rematured (76%) and laid a second egg batch (94%) from late September to early February. Although we finished the culture experiments in early February when all the test females had laid their second egg batch, a third spawning occurred in 27% of these females. Overall, the earlier the females spawned, the more egg batches they laid. Fecundity was correlated with female body size (postorbital carapace length) and decreased in accordance with spawning time. The egg development rate was very low in some females – probably depending on male fertility. We highlight future research subjects for developing a continuous breeding system in P. clarkii. [ABSTRACT FROM AUTHOR]

ABSTRACT An experiment was conducted to evaluate the effect of the intake of a mixture of fish and sacha inchi oils (iOM), organic selenium (iSe), and organic chromium (iCr) on egg production (EP) and feed conversion ratio (FCR) of Isa Brown second-cycle laying hens (SCLH) for 16 weeks (91-106 weeks old). Egg production and FCR were evaluated using multivariate models that included conventional equations and artificial neural networks (ANN) to study multiple nutritional interactions as alternatives to univariate dose-response models. Based on the best models, iOM, iSe, and iCr levels were optimized, and a global sensitivity analysis was implemented to quantify their influence on EP and FCR. The modified logistic model was selected as the best strategy to represent EP. In the case of FCR, an ANN model with a feed-forward architecture and softmax transfer function was selected as the best alternative. One of the scenarios to simultaneously optimize EP (89.1%) and FCR (1.94 kg feed/kg egg) at 16 weeks of production was established with 3.3 g/hen·day of iOM, 0.132 mg/ hen·day of iSe, and 0.176 mg/hen·day of iCr. However, optimization considering only FCR results in much lower optimal iCr levels (between 0.083 and 0.105 mg/hen·day) with a slight decrease in EP (87.9%). The global sensitivity analysis showed that iSe is an essential factor associated with the increase in EP, and iCr is the most influential factor for the decrease in FCR. When both criteria were taken into account simultaneously from a desirability function, iSe was the most critical factor.

Many insects are drawn to the heat, ash, and smoke produced by forest fires and arrive in large numbers at recent burns, often while the fire is still active. Some of these insects are pyrophilic and reproduce exclusively in the immediate aftermath of fire but are rarely, if ever, collected from unburnt habitats. Numerous observations made at active fires note an apparent preference among some pyrophilic insects to oviposit exclusively in the burnt portions of trees, raising broader questions about the adaptive benefits of reproduction in the post‐burn environment. Here, we tested whether the reproductive output of pyrophilic ground beetles (i.e., Sericoda spp.) increased in heat‐sterilized soils. In the first experiment, the eggs of Sericoda quadripunctata were reared in three types of soil collected from burnt forests: recently burnt soil (collected 1–2 weeks after the fire), soil collected 1 year after burn, and soil from an unburnt patch of forest adjacent to the fire. Daily monitoring through a dissecting microscope documented extensive predation of eggs by soil microarthropods (mites, springtails, and nematodes), especially in 1‐year‐old and unburnt soil treatments. This led to a second experiment that included the same three treatments and an additional fourth soil treatment: recently, burnt soil reheated to 100°C for 2 h (i.e., reheated soil). In this experiment, male and female pairs (n = 100) of Sericoda obsoleta were reared for 14 days in jars containing 90 g of soil corresponding to each of the four soil treatments. Reproductive output, measured as the number of larvae produced by each breeding pair, was significantly higher in the reheated soil, suggesting that heat sterilization and removal of soil‐dwelling predators improved egg survival. Our findings suggest that pyrophily in insects may have evolved as a means of increasing reproductive output in the post‐burn environment through access to heat‐sterilized ovipositing substrates. Furthermore, the abrupt disappearance of Sericoda and other pyrophilic insects following fire may be explained by suboptimal reproductive conditions as the burn is colonized by other organisms and by local emigration in favor of other recent burns on the landscape. [ABSTRACT FROM AUTHOR]

Beekeepers experience high annual losses of colonies, with environmental stressors like pathogens, reduced forage, and pesticides as contributors. Some factors, like nutritional stress from reduced flower abundance or diversity, are more pronounced in agricultural landscapes where extensive farming limits pollen availability. In addition to affecting other aspects of colony health, quantity and quality of pollen available are important for colony brood production and likely for queen egg laying. While some US beekeepers report >50% of colony loss due to queen failure, the causes of poor-quality queens are poorly understood. Access to resources from native prairie habitat is suggested as a valuable late-season resource for honey bees that can reverse colony growth declines, but it is not clear how prairie forage influences queen egg laying. We hypothesized that the pollen resources present in an extensive Midwestern corn/soybean agroecosystem during the critical late season period affect honey bee queen egg laying and that access to native prairies can increase queen productivity. To test this, we designed a field experiment in Iowa, keeping colonies in either soybean or prairie landscapes during a critical period of forage dearth, and we quantified queen egg laying as well as pollen collection (quantity and species). Then, using pollen collected in the field experiments, we created representative dietary mixtures, which we fed to bees using highly controlled laboratory cages to test how consumption of these diets affected the egg laying of naive queens. In two out of three years, queens in prairies laid more eggs compared to those in soybean fields. Pollen quantity did not vary between the two landscapes, but composition of species did, and was primarily driven by collection of evening primrose (Oenothera biennis). When pollen representative of the two landscapes was fed to caged bees in the laboratory queens fed prairie pollen laid more eggs, suggesting that pollen from this landscape plays an important role in queen productivity. More work is needed to tease apart the drivers of these differences, but understanding how egg laying is regulated is useful for designing landscapes for sustainable pollinator management and can inform feeding regimes for beekeepers.

Abstract Many insects are drawn to the heat, ash, and smoke produced by forest fires and arrive in large numbers at recent burns, often while the fire is still active. Some of these insects are pyrophilic and reproduce exclusively in the immediate aftermath of fire but are rarely, if ever, collected from unburnt habitats. Numerous observations made at active fires note an apparent preference among some pyrophilic insects to oviposit exclusively in the burnt portions of trees, raising broader questions about the adaptive benefits of reproduction in the post‐burn environment. Here, we tested whether the reproductive output of pyrophilic ground beetles (i.e., Sericoda spp.) increased in heat‐sterilized soils. In the first experiment, the eggs of Sericoda quadripunctata were reared in three types of soil collected from burnt forests: recently burnt soil (collected 1–2 weeks after the fire), soil collected 1 year after burn, and soil from an unburnt patch of forest adjacent to the fire. Daily monitoring through a dissecting microscope documented extensive predation of eggs by soil microarthropods (mites, springtails, and nematodes), especially in 1‐year‐old and unburnt soil treatments. This led to a second experiment that included the same three treatments and an additional fourth soil treatment: recently, burnt soil reheated to 100°C for 2 h (i.e., reheated soil). In this experiment, male and female pairs (n = 100) of Sericoda obsoleta were reared for 14 days in jars containing 90 g of soil corresponding to each of the four soil treatments. Reproductive output, measured as the number of larvae produced by each breeding pair, was significantly higher in the reheated soil, suggesting that heat sterilization and removal of soil‐dwelling predators improved egg survival. Our findings suggest that pyrophily in insects may have evolved as a means of increasing reproductive output in the post‐burn environment through access to heat‐sterilized ovipositing substrates. Furthermore, the abrupt disappearance of Sericoda and other pyrophilic insects following fire may be explained by suboptimal reproductive conditions as the burn is colonized by other organisms and by local emigration in favor of other recent burns on the landscape.

Chemosensory cells across the body of Drosophila melanogaster evaluate the environment to prioritize certain behaviors. Previous mapping of gustatory receptor neurons (GRNs) on the fly labellum identified a set of neurons in L-type sensilla that express Ionotropic Receptor 94e (IR94e), but the impact of IR94e GRNs on behavior remains unclear. We used optogenetics and chemogenetics to activate IR94e neurons and found that they drive mild feeding suppression but enhance egg laying. In vivo calcium imaging revealed that IR94e GRNs respond strongly to certain amino acids, including glutamate, and that IR94e plus co-receptors IR25a and IR76b are required for amino acid detection. Furthermore, IR94e mutants show behavioral changes to solutions containing amino acids, including increased consumption and decreased egg laying. Overall, our results suggest that IR94e GRNs on the fly labellum discourage feeding and encourage egg laying as part of an important behavioral switch in response to certain chemical cues. [Display omitted] • Activation of IR94e taste cells on the labellum produces mild feeding aversion • Neural circuits connect IR94e neurons to OviDNs, and IR94e activity increases egg laying • IR94e taste cells respond to certain amino acids through an IR94e receptor complex • IR94e mutants have changes in feeding and oviposition behaviors to amino acids Guillemin et al. describe how a distinct set of taste cells on the labellum that express IR94e function in behavior. They find that IR94e chemosensory neurons discourage feeding but increase egg laying and reveal that amino acids, particularly glutamate, stimulate IR94e cells through the IR94e receptor. [ABSTRACT FROM AUTHOR]

Rhinocricus duvernoyi (Karsch 1881) is an endemic diplopod from Cuba that lives in the west of the archipelago, in micro-localities like the Escaleras de Jaruco-Tapaste-Cheche Protected Natural Landscape, the place where the study was carried out. The place was visited periodically from April to September for 5 years. In the field, laying sites were observed and the number of eggs from each site was counted; in the laboratory eggs were measured and photographed. The eggs are spherical, white, 1.9 mm in diameter, and are associated with the feces of the same species. The laying of eggs takes place in groups of individuals. [ABSTRACT FROM AUTHOR]

The broadbean seed beetle (Bruchus rufimanus Boheman, 1833) is a major pest of faba bean (Vicia faba L.) almost everywhere this crop is grown. The main tasks of this research were to study the seed beetle's phenology, and rates of egg laying, larval survival and the emergence of young adults before the harvest. Studies were done in field conditions in farms located in various places in Latvia. The highest density of imagines was observed at a time when the plants were flowering intensively. Egg laying began as soon as the pods had formed in the lower third of the stem and lasted 4–5 weeks. In severe infestation happened, more than 34 eggs were laid per pod. The percentage of damaged yield increased in proportion to the average number of eggs laid on pods until this number reached 11–12 eggs per pod and remained at approximately the same level also when egg-laying rate was higher. In several fields, no seeds with imago exit holes were found in the samples few days before harvest, while in other sowings, the proportion of such seeds exceeded 90% of the total amount of damaged yield. [ABSTRACT FROM AUTHOR]

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), is one of the most important pests of fruits worldwide. In the present study, we investigated the ovipositional response of C. capitata females to 37 compounds of fruit volatiles from various chemical groups and the dose response to five of them. Red plastic hollow hemispheres (domes) were used as oviposition substrates in all tests. Twenty of the compounds tested increased female egg laying compared to control substrates that contain no chemicals. With 16 compounds, similar number of eggs was deposited in treated and in control oviposition substrates. One terpene ((±)-linalool) reduced egg laying indicating a deterrent ovipositional effect. Both the esters and aldehydes tested increased the ovipositional responses in C. capitata. Most of the monoterpene hydrocarbons increased oviposition, while oxygenated monoterpenes, sesquiterpenes hydrocarbons, and oxygenated sesquiterpenes had mostly neutral effect. Ethyl hexanoate and R- (+)-limonene increased oviposition in the majority of doses tested. Different doses of (−)-linalool elicited differential female ovipositional responses. In contrast, valencene and citral, regardless of dose did not affect female oviposition. Practical implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

Brood parasites, such as the Common Cuckoo (Cuculus canorus), rely on manipulating hosts from other species to raise their offspring. Selection should favor individuals that are able to identify and choose host nests that closely match the incubation stage of their own eggs. While intuitive, and supported by the findings of numerous long-term monitoring studies, experimental evidence of this remains sparse. By using video monitoring, we used three experimental groups to explore whether Common Cuckoos preferentially choose host Oriental Reed Warbler (Acrocephalus orientalis) nests that are early in their laying cycle. We found that Common Cuckoos preferentially parasitize nests of the host Oriental Reed Warbler that are earlier in their laying (less vs. more eggs) or nesting cycle (eggs vs. chicks), and videos of our experiments provide direct insights into their decision making process. Our results provide strong experimental evidence that Common Cuckoos are able to assess nesting stage and strategically choose nests that increase the likelihood of successful parasitism.

ABSTRACT Two experiments were carried out with the objective of evaluating the effect of superdosing of two phytases on performance, egg quality, digestive organ biometry and bone quality of light hens in the first (58 weeks) and second (87 weeks) productive cycle. In the first cycle, 270 light hens were used, in which a completely randomized design was adopted in a 2 x 2 + 1 factorial scheme (bacterial phytase or fungal phytase x 450 FTUs or 900 FTUs + control diet). In the second cycle, 270 hens were used, following the same design as the previous experiment. The performance and quality of the eggs were evaluated in both cycles, and the biometry of the digestive organs and bone characteristics were also evaluated in the first experiment. There was no effect in the comparison between the means for the performance and egg quality (in both experiments), or for the biometric variables and bone characteristics (first experiment). There was no significant interaction between the factors for any of the variables in the two experiments. In the first experiment, egg production was higher with bacterial phytase and egg weight with fungal phytase. The mineral matter showed greater value with 450 FTUs. It is recommended to use bacterial phytase produced from Escherichia coli as it improves the performance of light laying hens. The dosage of 450 FTUs improves the mineral content of light laying hens and the use of phytase in the laying hen diet implies a lower feed cost.

ABSTRACT An experiment with 23 diets was performed to evaluate the effect of digestible lysine (Lys), digestible methionine + cysteine (Met+Cys), and digestible threonine (Thr) on egg production of H&N Brown second-cycle laying hens (SCLH) for 20 weeks (92-111 weeks of age) in cages under environmental conditions. Body weight (BW), feed intake (FI), feed conversion ratio (FCR), egg weight (EW), number of hen-housed eggs, and livability were also evaluated during the experiment. Diets were formulated from a central composite design that combined five levels of Lys, Met+Cys, and Thr ranging from 727 to 1159, 662 to 1055, and 552 to 882 mg/kg, respectively. Egg production (EP) data were evaluated through three different modeling strategies: egg production models, multivariate polynomial models, and artificial neural networks (ANN). A cascade-forward neural network with log-sigmoid transfer function was selected as the best model according to goodness-of-fit statistics in both identification and validation data. One of the best scenarios for EP of H&N Brown SCLH under specific outdoor conditions was established at Lys, Met+Cys, and Thr levels of 1138, 1031, and 717 mg/hen·day, respectively. The ANN model may be an appropriate tool to study and predict EP of H&N Brown SCLH based on the combination of three different levels of essential digestible amino acids. The strategies included in this work may contribute to improving poultry performance based on modeling techniques to study other production parameters in terms of different nutritional requirements and productive conditions.

The toxicity and addictive liability associated with cocaine abuse are well-known. However, its mode of action is not completely understood, and effective pharmacotherapeutic interventions remain elusive. The cholinergic effects of cocaine on acetylcholine receptors, synthetic enzymes, and degradative enzymes have been the focus of relatively little empirical investigation. Due to its genetic tractability and anatomical simplicity, the egg laying circuit of the hermaphroditic nematode, Caenorhabditis elegans, is a powerful model system to precisely examine the genetic and molecular targets of cocaine in vivo. Here, we report a novel cocaine-induced behavioral phenotype in C. elegans, cocaine-stimulated egg laying. In addition, we present the results of an in vivo candidate suppression screen of synthetic enzymes, receptors, degradative enzymes, and downstream components of the intracellular signaling cascades of the main neurotransmitter systems that control C. elegans egg laying. Our results show that cocaine-stimulated egg laying is dependent on acetylcholine synthesis and synaptic release, functional nicotinic acetylcholine receptors, and the C. elegans acetylcholinesterases. [ABSTRACT FROM AUTHOR]

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Monarch butterfly (Danaus plexippus) populations have declined over the last two decades, attributable in part to declines in its larval host plant, milkweed (Asclepias spp.), across its breeding range. Conservation efforts in the United States call for restoration of 1.3 billion milkweed stems into the Midwestern landscape. Reaching this goal will require habitat establishment in marginal croplands, where there is a high potential for exposure to agrochemicals. Corn and soybean crops may be treated with neonicotinoid insecticides systemically or through foliar applications to provide protection against insect pests. Here, we investigate whether ovipositing monarchs discriminate against milkweed plants exposed to the neonicotinoid insecticide imidacloprid, either systemically or through foliar application. In our first experiment, we placed gravid females in enclosures containing a choice of two cut stems for oviposition: one in 15 ml of a 0.5 mg/ml aqueous solution of imidacloprid and one in 15 ml water. In a second experiment, females were given a choice of milkweed plants whose leaves were treated with 30 µl of a 0.825 mg/ml imidacloprid-surfactant solution or plants treated with surfactant alone. To evaluate oviposition preference, we counted and removed eggs from all plants daily for 3 d. We also collected video data on a subset of butterflies to evaluate landing behavior. Results indicate that neither systemic nor foliar treatment with imidacloprid influenced oviposition behavior in female monarchs. The implications of these findings for monarch conservation practices will be informed by the results of ongoing egg and larval toxicity studies. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the effects of dietary supplementation of various Dexamethasone (DEX) concentrations on productive and reproductive performance of premature male and female Japanese quails. Japanese quail of 3-weeks-old were received DEX at 0 (control group), 0.25 (low dose treated group) and 0.5 (high dose treated group) mg/kg diet, mixed in their mash, till the 42th day of age. As a result of this study, in high dose treated group, there were significant (P≤ 0.05) increases in the sex organs weight (g) and laying rate (%) of females meanwhile there was a significant decrease in egg weight and fertility percentage (P≤ 0.001). No significant differences were observed in total testes weight (g) of males but cloacal gland area (mm2) was smaller in both low and high dose male groups compared to control. The serum corticosterone (CORT) level was significantly (P≤ 0.001) higher in low dose treated males whereas no significant changes were recorded in high and low doses treated females. Conversely, a significant (P≤ 0.008) increase in serum estradiol level was measured in treated females but there were no significant changes in serum testosterone level in treated males. The medullary tissues of the adrenal glands were increased on the expense of cortical tissues in birds treated with higher dose of DEX. The seminiferous tubules of the low and high dose treated males did not show all the stages of spermatogenesis and most of the till spermatid stage was inspected with morphologically abnormal cell. The present results concluded that sex differences exist in response to DEX administration prior to reproduction, which may be due to the different prevalence of certain sex steroids influences in specific periods of life. [ABSTRACT FROM AUTHOR]

The copulation, egg laying, embryonic development and changes in amino acids and fatty acids in Neptunea arthritica cumingii during embryogenesis were studied to understand the embryo development process and nutritional requirements in the early life phase. The results showed that N. arthritica cumingii has direct development within the egg capsule and the development of embryos was classified into five stages: cleavage, egg swallowing, protoconch forming, shell development and juvenile. Embryos develop through the provision of nurse eggs as an extra‐embryonic source of nutrition. As development continued, the body of the embryo began to coil. After about 70–80 days, young N.arthritica cumingii started to emerge through a hole underneath the capsule. Biochemical results showed that the total amount of amino acids showed a decreasing trend as embryonic development progressed. The content of all nine essential amino acids decreased significantly from the egg‐swallowing stage to the post‐larva stage (p <.05). Concentrations of five of the seven nonessential amino acids also showed a decreasing trend from the egg‐swallowing stage to the post‐larva stage; the exceptions were Ala and Gly. Gly is the only amino acid that consistently increased in concentration during the development process. Most fatty acids increased after the eggs hatched, except for C20:1, C20:2, C22:5 and C22:6 (docosahexaenoic acid, DHA). The data in this study may provide a starting point for the formulation of well‐balanced early‐stage larval diets, although N.arthritica cumingii is still in the exploration stage. [ABSTRACT FROM AUTHOR]

ABSTRACT We evaluated the effect of adding proteases in diets of laying hens at peak production on the performance, egg quality, relative weight of digestive organs, and intestinal morphometry. Hy-Line W36 layer hens (390; 28-39 weeks old) were distributed in five treatments, with 13 animals each, with six replicates. The treatments were: control (standard formulation without nutritional reduction or protease inclusion), negative control A - NCA (nutritional reduction according to protease A matrix, without protease), negative control B - NCB (nutritional reduction according to protease B matrix, without protease), NCA + protease A, and NCB + protease B. The experimental period lasted 12 weeks, divided into three cycles of 28 days. Hens subjected to treatments (NCA and NCB) showed a decrease in feed intake. However, the addition of proteases A and B promoted improvement in this trait. The diets NCA and NCB had a negative influence on the production rate of the hens, but the diet supplementation with protease B resulted in significant improvement on egg laying rate. Hens subjected to nutritional reduction presented the worst results regarding mass and conversion by egg mass. However, the addition of enzymes reversed these results. Although the diets did not affect the relative weights of yolk, albumen, eggshell, Haugh unit, and specific gravity of the eggs, a higher eggshell thickness was observed in hens that received NCA, NCB, and NCB + protease B diets. The diets did not influence the relative weights of digestive organs and the small intestine morphometry. Hens fed diets supplemented with A and B have performance recovered in relation to those that received diets with reduced levels of nutrients.