Decreased Egg Production Research Articles

Cell Culture-based Influenza Vaccines as Alternatives to Egg-based Vaccines

Influenza viruses have raised public health concerns by seasonal epidemics and intermittent pandemics. Vaccination is considered as the most effective method for preventing influenza infection in humans. Current influenza vaccines are mostly produced in fertile chicken eggs. However, disadvantages of egg-based vaccines, such as egg dependency, labor-intensive manufacturing system, and huddle for large-scale output, allow us to make an alternative method. A cell-culture platform may be a fine alternative for the next generation vaccine technique. Compared with a classical egg-based method, cell-grown vaccines provide stable pipeline even in the pandemic situation with shorter lead-in times. In addition, cell-grown vaccines are flexible for altering production scales because stocked cell batches can be easily sub-cultured in large quantity without worrying avian diseases and a resultant decrease in egg production. By World Health Organization, MDCK, PER.C6, and Vero cells are only recommended for manufacturing influenza vaccines. In this review, we discuss the necessity, immunogenicity, and efficacy of cell-grown influenza vaccines compared with egg-based vaccines.

Isolation of avian influenza H5N1 virus from vaccinated commercial layer flock in Egypt

BackgroundUninterrupted transmission of highly pathogenic avian influenza virus (HPAIV) H5N1 of clade 2.2.1 in Egypt since 2006 resulted in establishment of two main genetic clusters. The 2.2.1/C group where all recent human and majority of backyard origin viruses clustered together, meanwhile the majority of viruses derived from vaccinated poultry in commercial farms grouped in 2.2.1.1 clade.FindingsIn the present investigation, an HPAIV H5N1 was isolated from twenty weeks old layers chickens that were vaccinated with a homologous H5N1 vaccine at 1, 7 and 16 weeks old. At twenty weeks of age, birds showed cyanosis of comb and wattle, decrease in egg production and up to 27% mortality. Examined serum samples showed low antibody titer in HI test (Log2 3.2± 4.2). The hemagglutinin (HA) and neuraminidase (NA) genes of the isolated virus were closely related to viruses in 2.2.1/C group isolated from poultry in live bird market (LBM) and backyards or from infected people. Conspicuous mutations in the HA and NA genes including a deletion within the receptor binding domain in the HA globular head region were observed.ConclusionsDespite repeated vaccination of layer chickens using a homologous H5N1 vaccine, infection with HPAIV H5N1 resulted in significant morbidity and mortality. In endemic countries like Egypt, rigorous control measures including enforcement of biosecurity, culling of infected birds and constant update of vaccine virus strains are highly required to prevent circulation of HPAIV H5N1 between backyard birds, commercial poultry, LBM and humans.

Proteomics of Tribolium castaneum seminal fluid proteins: Identification of an angiotensin-converting enzyme as a key player in regulation of reproduction

Seminal fluid proteins (SFPs) play important roles in regulation of reproduction and behavior. Proteomics approaches were used to identify 13 SFPs, including 3 new proteins in the red flour beetle, Tribolium castaneum. The 13 SFP genes identified code for Serpin, cysteine-rich protein, odorant binding protein-like (OBPL, G10064 and G10065), Kunitz-like protease inhibitor precursor, and WD 40 family protein and are predominantly expressed in the male accessory glands. The genes coding for 13 putative SFPs were knocked down in males; the RNAi males were mated with virgin females, and the number of eggs produced by the mated females was quantified. Knockdown in the expression of the gene coding for a protein similar to angiotensin-converting enzyme 9 (G15465, TcACE) in the males caused a decrease in egg production by the females when compared to the eggs produced by the females mated with control males. In addition, knockdown in the expression of the gene coding for heat shock cognate 70 led to a reduction in the amount of proteins produced by the male accessory glands by 55%. These data suggest that angiotensin-converting enzyme produced in the male seminal vesicles plays important roles in sperm protection during and after transfer to females.

The Effect of Different Levels of Canola Oil on Performance, Egg Shell Quality and Fatty Acid Composition of Laying Hens

The effects of different levels of canola oil (0.0, 2.0, 4.0 and 6.0%) on the performance, egg shell quality and fatty acid composition of laying hens were investigated in the present study. A total of 96 chickens consisting of 24 chickens in each group were used in the four groups. Feed and water were offered as ad libitum. Egg production was recorded daily, while feed intake was recorded weekly. Egg quality criteria were determined in 12 eggs from each group. The egg yolk fatty acid profile was determined with gas chromatography. The use of increasing levels of canola oil decreased egg production, egg weight and daily feed intake (in group including 6.0% canola oil, 70.98%, 61.68g, 109.52g respectively), although these mentioned parameters increased in the control group according to the other canola oil groups and conversely did not affect the feed conversion. In addition, supplementation of canola oil increased the yellow colour of the eggs and the egg-yellow index. On days 21 TBARS (Thiobarbituric Acid Reactive Substance) value significantly increased depending on increasing levels of canola oil (13.60, 14.78, 16.68, respectively), while on days 42 TBARS value did not change. The egg yolk lipid profile was not significantly difference in the canola oil groups, conversely decreased a very small amount of in the control group. The blood serum lipid profile decreased in the canola oil groups according to the control group. In the same time, monoacildigliserol also decreased in the canola additive groups. In parallel with increasing levels of canola oil (42.94, 42.14 and 43.51%, respectively), monounsaturated fatty acid (oleic acid) in the egg yolks significantly increased compared to the control group (36.05%). On the basis of the results, we concluded that canola oil supplementation into the diet of laying hens is important in producing monounsaturated fatty acid (MUFA)-rich functional eggs.

Geotaxis and leaf-surface preferences mitigate negative effects of a predatory mite on an herbivorous mite

Reproductive success and population growth of an herbivorous mite are limited by activities of phytoseiid predators. However, occurrences on upper versus lower leaf surfaces are sometimes mismatched between these prey and predators. The mismatch potentially mitigates predation risk for the prey species. We assessed factors that affect mite distributions on leaf surfaces, testing whether the presence of the phytoseiid mite Phytoseius nipponicus alters the leaf-surface distribution and reproductive success of the herbivorous false spider mite Brevipalpus obovatus. The host plant was Viburnum erosum var. punctatum (Adoxaceae). Leaves were set in natural (TRUE) and reversed (upside down; INVERTED) orientations using experimental devices. Both surfaces were accessible to mites. We detected lower and abaxial leaf-surface preferences in P. nipponicus. In contrast, upper and adaxial surfaces were preferred by B. obovatus. Thus, prey and predatory mites accumulated on different sides of leaves. Presence of the predator also indirectly decreased egg production in B. obovatus. Brevipalpus obovatus females actively avoided leaf surfaces with elevated predator numbers; these females shifted their distributions and changed oviposition sites to leaf surfaces with fewer predators. In consequence, B. obovatus eggs on the upper sides of leaves were less frequently preyed upon than were those on lower sides. We suggest that upper leaf-surface exploitation in this particular herbivorous mite species mitigates predation risk from phytoseiid mites, which prefer lower leaf surfaces.

Low Pathogenicity Avian Influenza Viruses Infect Chicken Layers by Different Routes of Inoculation

In order to develop better control measures against avian influenza, it is necessary to understand how the virus transmits in poultry. In a previous study in which the infectivity and transmissibility of the pandemic H1N1 influenza virus was examined in different poultry species, we found that no or minimal infection occurred in chicken and turkeys intranasally (IN) inoculated with the virus. However, we demonstrated that the virus can infect laying turkey hens by the intracloacal (IC) and intraoviduct (IO) routes, possibly explaining the drops in egg production observed in turkey breeder farms affected by the virus. Such novel routes of exposure have not been previously examined in chickens and could also explain outbreaks of low pathogenicity avian influenza (LPAI) that cause a decrease in egg production in chicken layers and breeders. In the present study, 46-wk-old specific-pathogen-free chicken layers were infected by the IN, IC, or IO routes with one of two LPAI viruses: a poultry origin virus, A/chicken/CA/1255/02 (H6N2), and a live bird market isolate, A/chicken/NJ/12220/97 (H9N2). Only hens IN inoculated with the H6N2 virus presented mild clinical signs consisting of depression and anorexia. However, a decrease in number of eggs laid was observed in all virus-inoculated groups when compared to control hens. Evidence of infection was found in all chickens inoculated with the H6N2 virus by any of the three routes and the virus transmitted to contact hens. On the other hand, only one or two hens from each of the groups inoculated with the H9N2 virus shed detectable levels of virus, or seroconverted and did not transmit the virus to contacts, regardless of the route of inoculation. In conclusion, LPAI viruses can also infect chickens through other routes besides the IN route, which is considered the natural route of exposure. However, as seen with the H9N2 virus, the infectivity of the virus did not increase when given by these alternate routes.

Effects of a premolt calcium and low-energy molt program on laying hen performance, egg quality, and economics

The objectives of this study were to evaluate and compare the effects of production, physiology, egg quality, and economics of laying hens housed in a cage system when offered a calcium premolt treatment and low-energy molt diets versus a traditional feed withdrawal (FW) treatment during and after molt. In total, 981 Hy-Line W-36 laying hens (85 wk of age) housed 3 per cage were used. Six treatments were compared in a 2 × 3 factorial design with 2 calcium premolt treatments (fine and coarse) and 3 molt diets (FW, soybean hulls, and wheat middlings). The coarse Ca was a 50:50 mix of fine (0.14-mm mean diameter) and coarse (2.27-mm mean diameter) CaCO3, whereas the fine Ca was an all-fine CaCO3. Both diets were formulated to contain 4.6% Ca, such that only the particle size of the CaCO3 differed. Production parameters in experiment 1 included egg production, egg weight and mass, specific gravity, Haugh units, egg components, feed consumption and utilization, and BW. Physiological parameters in experiment 2 included ovary and oviduct weights, femur- and humerus-ash percentages, heterophil to lymphocyte ratios, plasma Ca and inorganic P concentrations, and alkaline phosphatase activity. Data were analyzed by ANOVA and P < 0.05 was significant. The fine-Ca premolt treatment was more effective than the coarse-Ca treatment at decreasing egg production during molt and increasing it postmolt, regardless of the molt diet. The FW molt diet resulted in the greatest decrease in production, but the soybean hulls diet resulted in lower production and ovary and oviduct weights during molt compared with those of the wheat middlings molt diet. Therefore, a fine-Ca premolt treatment and a low-energy molt diet, particularly soybean hulls, can be useful alternatives to a FW molt.

Toxicity and nutritional inadequacy of Karenia brevis: synergistic mechanisms disrupt top-down grazer control

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 444:15-30 (2012) - DOI: https://doi.org/10.3354/meps09401 Toxicity and nutritional inadequacy of Karenia ­brevis: synergistic mechanisms disrupt top-down grazer control Rebecca J. Waggett1,2,*, D. Ransom Hardison1, Patricia A. Tester1 1National Ocean Service, National Oceanic and Atmospheric Administration, 101 Pivers Island Road, Beaufort, North Carolina 28516-9722, USA 2Present address: The University of Tampa, 401 W. Kennedy Blvd., Tampa, Florida 33606, USA *Email: rwaggett@ut.edu ABSTRACT: Zooplankton grazers are capable of influencing food-web dynamics by exerting top-down control over phytoplankton prey populations. Certain toxic or unpalatable algal species have evolved mechanisms to disrupt grazer control, thereby facilitating the formation of massive, monospecific blooms. The harmful algal bloom (HAB)-forming dinoflagellate Karenia brevis has been associated with lethal and sublethal effects on zooplankton that may offer both direct and indirect support of bloom formation and maintenance. Reductions in copepod grazing on K. brevis have been attributed to acute physiological incapacitation and nutritional inadequacy. To evaluate the potential toxicity or nutritional inadequacy of K. brevis, food removal and egg production experiments were conducted using the copepod Acartia tonsa and K. brevis strains CCMP 2228, Wilson, and SP-1, characterized using liquid chromatography-mass spectrometry (LC-MS) as having high, low, and no brevetoxin levels, respectively. Variable grazing rates were found in experiments involving mixtures of toxic CCMP 2228 and Wilson strains. However, in experiments with toxic CCMP 2228 and non-toxic SP-1 strains, A. tonsa grazed SP-1 at significantly higher rates than the toxic alternative. Additionally, A. tonsa experienced significantly greater mortality when exposed to toxic K. brevis strains, particularly after prolonged exposure. Egg production rates of copepods fed toxic K. brevis strains were similar to those of starved copepods, while those of copepods fed non-toxic SP-1 and the nutritious Rhodomonas salina were significantly higher. Analysis indicates that K. brevis impacts grazer populations via multiple synergistic mechanisms: (1) decreased ingestion rates, (2) decreased egg production, and (3) increased mortality of copepods through a combination of toxicity and nutritional inadequacy. KEY WORDS: Copepod grazing · Harmful algae · Toxic dinoflagellate · Chemical deterrent · Karenia brevis · Brevetoxin Full text in pdf format PreviousNextCite this article as: Waggett RJ, Hardison DR, Tester PA (2012) Toxicity and nutritional inadequacy of Karenia ­brevis: synergistic mechanisms disrupt top-down grazer control. Mar Ecol Prog Ser 444:15-30. https://doi.org/10.3354/meps09401 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 444. Online publication date: January 10, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

Prokaryotic expression and characteristics of duck enteritis virus UL29 gene

Duck enteritis virus (DEV) causes a contagious, acute and highly lethal disease in all ages of birds from the order Anseriformes. DEV leads to heavy economic losses to the commercial duck industry due to its high mortality rate and decrease in egg production. With development of molecular biology, more information about DEV genes is reported, nonetheless little information is known about DEV UL29 gene and its product major DNA-binding protein or infected-cell protein 8 (ICP8). The sequence characteristics of DEV UL29 gene was initially showed in our article. Phylogenetic tree analysis provided useful proof that DEV belongs to the subfamily Alphaherpesvirinae. The predicted characteristics of ICP8 amino acid sequence showed that ICP8 possesses good immunogenicity and is a hydrophobic protein. These findings correlate with the experimental results that ICP8 protein forms inclusion bodies in the prokaryotic expression system. By immunofluorescence we have identified ICP8 as nuclear protein. All the fundamental data in this article contribute to understanding the functions of DEV UL29 gene and its product ICP8.

Yumurtacı Tavuk Rasyonlarına Keten Tohumu ve Selenyum İlavesinin Performans, Yumurta Yağ Asidi Kompozisyonu ve Selenyum İçeriğine Etkisi

Summary In a 4×3 factorial experiment, six hundred 31-week-old laying hens were fed diets containing 0, 25, 50 and 100 g/kg linseed with control, 0.3 mg/kg organic selenium (OrSe) and 0.3 mg/kg inorganic selenium (InSe) to determine the effects of diet on performance, eggshell parameters, egg fatty acid composition and selenium (Se) content of eggs. Laying hens were randomly assigned to 12 experimental groups with 5 replications. Linseed supplementation decreased egg production (d 1- 30), feed consumption (d 1-30 and 1-90) and egg weight (d 60-90 and 1-90). Shell weight and thickness decreased when dietary linseed was increased. There were interactions between Se and linseed in feed consumption, feed efficiency, damaged egg ratio and shell thickness. The inclusion of InSe and OrSe increased the Se content of the eggs. Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), α-linolenic acid (ALA) and n-3 fatty acid concentrations in egg yolks increased with increasing dietary linseed. There were also interactions between linseed and Se in ALA and n-3 fatty acid concentrations. In conclusion, the addition of linseed to the diets increased DHA, EPA, ALA and n-3 fatty acid concentrations in egg yolks, and the addition of Se increased the Se content of the eggs. Egg fatty acids (ALA, n-3 fatty acid) were increased by supplementing dietary linseed with OrSe.

Isolation, identification and antibiotic sensitivity determination of Ornithobacterium rhinotracheale in slaughtering broiler chicken flocks of Guilan province

Summary Ornithobacterium rhinotracheale (ORT), a species of bacteria, is known to be associated with respiratory disease, growth retardation, mortality and decreased egg production. The aim of the present study was to determine seroprevalence of the infection and to identify the microorganism by bacteriological and molecular methods. In this study, 460 serum samples and also 290 tracheal swabs were collected from 29 broiler chicken flocks in slaughter houses. Serological results showed that 24 out of 460 (5.12%) serum samples related to 5 flocks were positive for ORT by ELISA test. ORT was isolated from tracheal swabs of 3 flocks (1.03% out of 290 tracheal swabs) by culture and confirmed as ORT by specific primers in PCR method. Statistically, there was no significant difference between the rate of isolation and ORT serum titers (P>0.05). Antibiotic sensitivity test using standard disk diffusion technique was performed with 13 antibiotics. All the isolates were resistant (100%) to erythromycin, tetracycline, oxytetracyclin, enrofloxacin, ciprofloxacin, flumequin, lincospectin, furazolidon, and 100% of them were found to be susceptible to ceftriaxon and tiamulin, but 2 isolates (66.7%) were moderately sensitive to tylosin and amoxicillin and sensitive to florfenicol. This study is the first report of the prevalence of ORT, bacterial isolation and molecular method in broiler chickens after broiler breeder vaccination in Guilan province.

Molecular characterization and phylogenetic analysis of neuraminidase gene of avian Influenza H9N2 viruses isolated from commercial broiler chicken in Iran during a period of 1998-2007

Avian influenza (AI) outbreaks due to H9N2 subtype of avian influenza virus (AIV) occurred in poultry industry in Iran, throughout the past decade and caused serious economic losses as a result of decreased egg production, increased mortality and the cost of vaccination in Iranian poultry industry. Our aim was to find the phylogenic and genetic relationships among avian influenza viruses recently isolated from poultry in Iran with other Asian H9N2 lineages (1998-2007). The complete nucleotide sequences of the neuraminidase (NA) genes of ten H9N2 influenza virus strain isolated from diseased chickens in different farms in Iran during 1998-2007, were amplified and sequenced and phylogenetic relationships between these and previously reported N2 genes were investigated. The viruses surface glycoprotein genes was >90% similar to those of A/Quail/Hongkong/G1/97 (H9N2) lineage. The NA stalks regions in these viruses had no deletion or insertion or shortening as compared to that A/DK/HK/Y280/97 lineage (CK/Bei-like viruses) and the 2 human isolates A/HK/1073/99, A/HK/1074/99. The hemadsorbing site of NA had up to 3 amino acid substitution and is different from those of earlier Iranian viruses and ten Iranian isolates possessed seven potential glycosylation sites like the most H9N2 isolates. Phylogenetic analysis of NA gene showed that they belonged to the same A/Quail/Hong Kong/G1/97 like virus sub lineage. Key words: Avian influenza virus, H9N2, neuraminidase gene, phylogenetic analysis, Iran.

GLUTAMINA NA DIETA DE POEDEIRAS LEVES SUBMETIDAS AO ESTRESSE PELO CALOR E À TERMONEUTRALIDADE

The aim of this study was to evaluate the effect of glutamine supplementation of the diet on intestinal mucosa morphology, performance, and egg quality of commercial laying hens, submitted to heat stress and thermoneutral conditions. In this study, 96 (Isa Babcock) laying hens at 35 weeks of age were used and distributed in a completely randomized design according to a 2x2 factorial arrangement, with two levels of ambient temperature (thermoneutral and hot) and two levels of glutamine in the diet (0.0 and 1.0% of inclusion), in 6 replicates of 4 hens per box. Feed intake, daily egg production, feed conversion per kilogram of eggs, and egg quality were obtained in two periods of 28 days each. Heat stress decreased egg production and quality, and glutamine supplementation improved egg quality and feed conversion. The heat and glutamine supplementation provided an increase in calliciform cells quantity in duodenum and ileum, respectively. Significant morphological modifications in the intestinal mucosa of laying hens were not found. KEYWORDS: egg quality; glutamine; intestinal morphology; thermal stress.

Management of protein intake in the fruit fly Anastrepha fraterculus

This work tested if carbohydrates and proteins ingestion is regulated in the South American fruit fly, Anastrepha fraterculus, to optimize survival and reproduction. Adult food treatments were established by providing sugar and hydrolyzed yeast in various combinations either alone or mixed at a standard 3:1 ratio (sugar:hydrolyzed yeast). Individual food consumption was assessed and related to survival patterns. The effects of adult feeding on fecundity and fertility patterns were investigated in groups of flies. Sugar consumption was the lowest in the treatment where it was provided with hydrolyzed yeast at a fixed 3:1 ratio. Consumption of hydrolyzed yeast did not differ between this treatment and the one in which this solution was complemented with one solution of sugar. It seems that a mixture of sugar and hydrolyzed yeast at a fixed ratio of 3:1, respectively, restricts extra ingestion of sugar; most probably because of negative response of the fly to overconsumption of protein. Survival was affected by the treatments, being lower in those cases where protein was at the fixed ratio. Group experiments revealed that protein restriction expanded longevity and decreased egg production. In contrast, egg production was enhanced when flies were kept continuously with a mixture of yeast and sugar plus an extra source of sugar, and this was not in detriment of survival. Our results suggest that fixed sugar-protein ratios in which protein is in excess affects fitness components such as longevity and reproduction. These findings are discussed from a theoretical and applied perspective in the context of pest control by means of the sterile insect technique.

Chlamydia psittaci infection in canaries heavily infested by Dermanyssus gallinae

Dermanyssus gallinae is a haematophagous ectoparasite responsible for anemia, weight loss, dermatitis and a decrease in egg production. Dermanyssus gallinae may play a role in the modulation of the host immune system, maybe predisposing the host to some bacterial infections such as chlamydiosis. This is an important zoonosis. Humans are exposed to Chlamydia psittaci through inhalation of the agent dispersed from the infected birds. In this study, a syndrome observed in an aviary of canaries was investigated. A heavy infestation by D. gallinae was reported. Simultaneously, a C. psittaci infection was molecularly confirmed in the canaries. Combined therapy was applied successfully. The association of C. psittaci with the examined mites has been confirmed. Therefore, we think that D. gallinae have played a role in the spreading of C. psittaci infection among the canaries. Moreover, D. gallinae could have played an important role predisposing the canaries to the development of chlamydiosis, by inducing anemia and debilitation. The control of mites in the aviaries may represent a crucial step for the prevention of important infection such as chlamydiosis in birds and humans.

Review: feed withdrawal and non feed withdrawal moult

Moulting is a natural phenomenon in birds. Temperature variation and photoperiodic changes induce circadian and circannual rhythms, manifested by changes in the neural and endocrine systems, ultimately causing physiological processes resulting in a moult. The concept of induced moulting by feed deprivation arose during the early part of the 20th century as a solution to economic challenges of decreased egg production in commercial layer flocks toward the end of the first laying cycle as they approached the moult phase. Efficiency of feed removal programs in enhancing post moult productivity and economical feasibility insured a gain in popularity by the 1930′s. In 2003, more than 75% of all flocks were moulted in the U.S. However, moulting with feed withdrawal caused risk to the health of birds by impairing the immune system and increasing susceptibility to various pathogens, especially Salmonella enteritidis (SE). During the 1980s, increased incidence of gastroenteritis due to SE was linked to forced moulting. The importance of challenges for conventional forced moulting was realized and animal activists, welfare organizations, researchers, consumers, and producers realized that alternative moulting methods were necessary. Ultimately, the United Egg Producers Scientific Advisory Committee, having dealt with the issue of feed withdrawal for moulting since the early 1990′s, amended the Animal Husbandry Guidelines for U.S. Egg Laying Flocks to specify the use of non feed withdrawal moult methods after January 1, 2006. Furthermore, moulting hens would have to be fed nutritionally adequate and palatable food suitable for non-egg producing hens. Though metals or hormones are efficient moult inducers, results of studies showed that they had disadvantages like residual effects and physiological alterations, respectively. Diets supplemented with low nutritious feed ingredients are safe and demonstrate promising outcomes. Unconventional feedstuffs such as coconut meal and cumin seed meal are successfully used in layer and non feed removal moults in Asian and Middle Eastern countries. In the western U.S. (especially in California), local ingredients like safflower meal and tomato pomace are promising alternatives.

Queen pheromone regulates egg production in a termite.

In social insects, resource allocation is a key factor that influences colony survival and growth. Optimal allocation to queens and brood is essential for maximum colony productivity, requiring colony members to have information on the total reproductive power in colonies. However, the mechanisms regulating egg production relative to the current labour force for brood care remain poorly known. Recently, a volatile chemical was identified as a termite queen pheromone that inhibits the differentiation of new neotenic reproductives (secondary reproductives developed from nymphs or workers) in Reticulitermes speratus. The same volatile chemical is also emitted by eggs. This queen pheromone would therefore be expected to act as an honest message of the reproductive power about queens. In this study, we examined how the queen pheromone influences the reproductive rate of queens in R. speratus. We compared the number of eggs produced by each queen between groups with and without exposure to artificial queen pheromone. Exposure to the pheromone resulted in a significant decrease in egg production in both single-queen and multiple-queen groups. This is the first report supporting the role of queen pheromones as a signal regulating colony-level egg production, using synthetically derived compounds in a termite.

Effect of Short-term Water Restriction on Body Weight, Egg Production, and Immune Response of Local and Commercial Layers in the Late Phase of Production

ABSTRACT : Forty-five Hisex commercial layers and forty-five local Saudi breed layers were used to determine the acceptable limit of short-term water restriction in the late phase of production, when the problem of high feed and water consumption is expected. The experiment was performed under hot and arid environmental conditions when the layers were at fifty weeks of age. Layers from each breed were randomly assigned in groups of five into nine floor pens. The average environmental temperature was 37.2-38.6°C, and the relative humidity was between 20 to 37%. The trial was divided into 3 periods; control (1 week), water restriction (2 weeks) and rehydration (1 week). During the restriction period, layers from each breed were divided into three groups that received 20, 40, and 0%restriction of drinking water relative to their consumed water during the control period. During the study, feed and water consumption, body weight, changes in body weight, egg production, primary antibody response to SRBC, and rectal temperature were evaluated. Water restriction did not result in any clear effect on feed intake in either breed, however, commercial layers tended to consume less feed compared to the local breed. Body weight declined with water restriction during the first week of restriction in the commercial breed regardless of rate of restriction, but it was delayed until the second week in the local breed. Water restriction of 40% decreased egg production in both breeds but with a delay of 1 week in the local breed. Antibody level to SRBC was not affected by water restriction in the commercial line while it was highly affected in the local breed. A water restriction of 20% is considered to be an acceptable limit under the current experimental conditions without a negative effect on egg production in both breeds and considering the immune status of the local breed. Whereas, 40% restriction had a negative effect on egg production, and varied effects in the other traits in both breeds.(

Endocrine disruptive synthetic estrogen (17α-ethynylestradiol) removal from aqueous phase through batch and column sorption studies: Mechanistic and kinetic analysis

Global concern about the persistence of endocrine disrupting chemicals (EDC) in the freshwater environment is more evident due to their possible disruptive effects. Even at nanogram levels these compounds increase the risk of cancer, decrease egg and sperm production, reduce gamete quality and tend complete feminization of the male fish. The present study demonstrated the potential of activated charcoal as adsorbent in removing synthetic estrogen 17α-ethynylestradiol (EE2) from aqueous phase by sorption process employing both agitated batch and column adsorption experiments. Batch sorption studies showed good removal of EE2 and dependent on the concentration loaded. Equilibrium data of EE2-charcoal sorption system showed a reasonably good fit with pseudo first-order kinetic plot. Intra-particle diffusion plot indicated the complex nature of EE2-charcoal sorption system involving both boundary layer and intra-particle diffusions. Experimental data confirmed to linear Langmuir's isotherm model. Highest EE2 sorption capacity of activated charcoal was observed at neutral conditions. Fixed bed column studies were performed with EE2 spiked untreated domestic sewage. Based on the data derived by fixed bed column studies, rapid small-scale column test (RSSCT) methodology was used to design full-scale GAC system. Total EE2 concentration was quantitatively estimated by direct competitive immuno-enzymatic colorimetric method.

Oil exposure in a warmer Arctic: potential impacts on key zooplankton species

Oil exploration activities are rapidly increasing in Arctic marine areas with potentially higher risks of oil spills to the environment. Water temperatures in Arctic marine areas are simultaneously increasing as a result of global warming. Potential effects of a combination of increased water temperature and exposure to the PAH pyrene were investigated on fecal pellet and, egg production and hatching success of two copepod species, Calanus finmarchicus and Calanus glacialis, sampled in Disko Bay, Greenland on 23–25 April 2008. The two species were exposed daily to nominal pyrene concentrations of 0-0.01-0.1-1-10-100 nM at water temperatures of 0.5, 5 and 8°C for 9 and 7 days, respectively. Daily measurements of faecal pellet production, egg production and hatching showed different responses of the two species to the applied stressors. When temperature increased, low concentrations of pyrene caused a decrease in faecal pellet production by C. finmarchicus, whereas C. glacialis faecal pellet production showed no negative response to pyrene exposure when temperatures increased. Pyrene exposure decreased egg production of C. finmarchicus at all temperatures, but the species was more sensitive at 0.5 and 8°C. A lag period of 1 day before egg production began was prolonged with several days when warmer water was combined with pyrene exposure. Egg production by C. glacialis was only negatively affected by pyrene in a dose-dependent manner at 0.5°C. Hatching success in both species was not affected by pyrene, where increased water temperatures led to a higher hatching success. In conclusion, C. glacialis seemed to be the less sensitive of the two species to the stress combination of increased water temperature and pyrene exposure. As a consequence of the differential responses of the two species, their competition can be impaired with a consequent impact on energy transfer between trophic levels.