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Egg Quality (egg + quality)
Selected AbstractsProduction, Quality, and Low Temperature Incubation of Eggs of Atlantic Cod Gadus morhua and Haddock Melanogrammus aeglefinus in CaptivityJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2000Lawrence J. Buckley Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus broodstock maintained under altered regimens of temperature and photoperiod spawned up to 8 mo per year. The cod broodstock produced viable embryos from October through June. The haddock broodstock produced viable embryos from December through May. Egg diameters were largest during the middle of the spawning season when water temperature was at a minimum, resulting in an inverse relationship between egg diameter and water temperature in both species. Egg quality was high, as evaluated by buoyancy, fertilization rate, regularity of early cleavage, and percent viable hatch. Low temperature incubation of cod and haddock eggs extended the embryonic period. Cod embryos tolerated a wider range of temperatures than haddock. High mortality (1 90%) was observed before hatching in haddock embryos incubated at 1 C. Atlantic cod embryos hatched at temperatures as low as ,1 C, extending the embryonic period to 59 d. At 8 C Atlantic cod and haddock embryos hatched in 11,12 d. To determine if extending the embryo incubation time by using low temperatures had a detrimental effect, embryos were incubated through hatch at either 1 C or 6 C, and the larvae from both groups reared at 6 C. Growth and early survival of larvae were comparable in both treatments. [source] Adult female crickets, Gryllus texensis, maintain reproductive output after repeated immune challengesPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2007KELLY L. SHOEMAKER Abstract Both immunity and reproduction are thought to be energetically costly and therefore likely to make trade-offs with one another. To assess whether increasing immune system activity results in a decline in egg production, the immune system in the cricket Gryllus texensis is activated over a period of 12 days with regular injections of lipopolysaccharide (LPS) derived from Serratia marcescens, and the number of eggs laid during this time counted. Egg quality is also assessed by measuring total protein of eggs laid, fertilization and hatching success, and the weight of individual eggs laid after the series of injections. Indirect evidence suggests that LPS induces an immune response in G. texensis. However, the number of eggs produced is not affected. There is also no effect of repeated LPS injections on female weight, egg protein content, or fertilization and hatching success. Taken together, these results suggest that with food and water provided ad libitum, females can protect many aspects of fitness in the face of increased immune system activity. However, there is some evidence to suggest that large (100 ,g) doses of LPS lead to reduced female longevity, and also in egg weight that could affect offspring success. Although the possibility exists that the decline in lifespan and egg weight after high-dose injections reflects a trade-off between reproduction and immune investment, another possibility is that these doses yield nonspecific effects, or that the high-dose induces an overwhelming immune response that leads to self-damage. [source] Laboratory-based reproduction success of ruffe, Gymnocephalus cernuus (L.), in brackish water is determined by maternal propertiesECOLOGY OF FRESHWATER FISH, Issue 2 2006A. Albert Abstract,, Body length, age, egg size, embryo salinity tolerance and length at hatching of the freshwater (salinity <0.1 ppt, Lake Peipsi) and brackish-water (salinity 2,6 ppt, Pärnu and Matsalu Bay) ruffe, Gymnocephalus cernuus (L.), were examined to reveal their reproductive success in moderate salinity. Eggs of females originating from brackish water were significantly larger than eggs of freshwater females. No correlation between egg size and female size and age was found in brackish-water populations. In the freshwater population there was a small negative correlation between egg size and female size, but no correlation with female age. Fertilisation by sperm of males of different origin (brackish water or freshwater) produced no significant differences at any critical developmental stage (fertilisation, gastrulation, hatching) in the development of eggs from brackish-water or freshwater females at 3.3, 5.5, 7.7 and 9.9 ppt salinity. Survival rates in different salinity depended only on female origin; embryonic salinity tolerance was higher in ruffe inhabiting brackish water. Obviously, embryo salinity tolerance in ruffe is determined by egg qualities. [source] Rearing conditions determine offspring survival independent of egg quality: a cross-foster experiment with Oystercatchers Haematopus ostralegusIBIS, Issue 2 2006MARTIJN VAN DE POL Variation in rearing conditions, due either to parental or to environmental quality, can result in offspring of different quality (e.g. body condition, immune function). However, evidence is accumulating that egg size and composition can also affect offspring quality. In Oystercatchers Haematopus ostralegus, high-quality rearing conditions result in a higher quantity as well as quality of offspring. This is thought to be caused by increased parental food provisioning to the chicks in high-quality environments. However, variation in egg quality between rearing conditions could also affect the quantity and quality of offspring. Determining the mechanism and ontogeny of quality differences is important in unravelling the causes of variation in reproductive success. To disentangle the effects of egg quality, and quality of the rearing conditions, on the future survival of offspring, we cross-fostered complete clutches between nests. When reared under conditions of similar environmental quality, chicks originating from eggs laid in low-quality environments survived as well as chicks originating from eggs laid in a high-quality environment. However, chicks reared in high-quality environments survived twice as long as chicks reared in low-quality environments, independent of the environmental quality in which the eggs were laid. This suggests that variation in the future survival of offspring is primarily caused by differences in environmental and/or parental quality, with no clear effect of egg quality (size). [source] Successful gonadal development and maturation of tench (Tinca tinca L.) in small concrete pondsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2003J. M. Carral Summary The experiments were performed in a tench farm from autumn until the spawning season (June,July). Tench broodstocks from natural habitats were maintained in 25 × 6 × 1 m concrete ponds and fed on commercial trout pellets. Females and males were separated and maintained under natural photoperiod and temperature conditions at densities around 2 kg m,2. Water flow throughout was supplied at the rate of 15 L s,1. When females showed external signs of advanced gonadal development, induction of spawning was made by luteinizing hormone releasing factor (LH-RH) synthetic analogue administration at three different periods of the reproductive season (June,July). A single intramuscular injection (20 ,g kg,1 body weight) was administered to 110 mature females selected from a total of 150. The females were stripped 42 h (22°C) after hormone administration. The mean rate of stripped females to the number injected was 77%. Mean relative egg weight in relation to the weight of the stripped females was 5.61%. More than 90% of the males provided semen without hormonal induction. Differences in egg production and external egg quality were observed at different times of the spawning period. It was proven that tench maintained in small concrete tanks and fed on artificial diets were able to reach gonadal maturation. [source] Early maternal, genetic and environmental components of antioxidant protection, morphology and immunity of yellow-legged gull (Larus michahellis) chicksJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2006D. RUBOLINI Abstract Maternal effects mediated by egg quality are important sources of offspring phenotypic variation and can influence the course of evolutionary processes. Mothers allocate to the eggs diverse antioxidants that protect the embryo from oxidative stress. In the yellow-legged gull (Larus michahellis), yolk antioxidant capacity varied markedly among clutches and declined considerably with egg laying date. Analysis of bioptic yolk samples from clutches that were subsequently partially cross-fostered revealed a positive effect of yolk antioxidant capacity on embryonic development and chick growth, but not on immunity and begging behaviour, while controlling for parentage and common environment effects. Chick plasma antioxidant capacity varied according to rearing environment, after statistically partitioning out maternal influences mediated by egg quality. Thus, the results of this study indicate that egg antioxidants are important mediators of maternal effects also in wild bird populations, especially during the critical early post-hatching phase. [source] Effect of elevated summer temperatures on gonadal steroid production, vitellogenesis and egg quality in female Atlantic salmonJOURNAL OF FISH BIOLOGY, Issue 1 2003H. R. King Groups of Tasmanian female Atlantic salmon Salmo salar L. were maintained at 14, 18 and 22° C for 3 months from mid-summer (January). Blood plasma levels of 17,-oestradiol (E2), testosterone (T), cortisol and vitellogenin (Vtg) were measured at regular intervals, and in autumn (April) temperatures were reduced to 8° C to facilitate spawning and egg incubation. Maintenance at 22° C during vitellogenesis was associated with a general reduction in plasma E2 levels and an early reduction in plasma Vtg levels relative to those observed in fish held at 14 and 18° C. Significantly reduced oocyte diameters in ova from fish held at 22° C (5·4 mm cf. 5·7 mm) confirmed reduced maternal investment, and an increase in the incidence of previously undescribed chorion damage suggested that zonagenesis may also have been impaired. As a result, the fertility and survival of ova from fish exposed to 22° C (69 and 42%, respectively) were significantly reduced relative to those of ova from fish maintained at 14° C (93 and 86%) and 18° C (86 and 84%). [source] Combination of Super Chilling and High Carbon Dioxide Concentration Techniques Most Effectively to Preserve Freshness of Shell Eggs during Long-Term StorageJOURNAL OF FOOD SCIENCE, Issue 1 2010T. Yanagisawa ABSTRACT:, This study was made to examine the combined effects of stored temperature and carbon dioxide atmosphere on shell egg quality. The shell eggs were packed into polyethylene terephthalate/polyethylene (PET/PE) pouches and stored at 0 °C (super chilling), 10 °C, and 20 °C, respectively for 90 d. The atmospheric carbon dioxide concentration was controlled to obtain the 3 concentration levels of high (about 2.0%), medium (about 0.5%), and low (below 0.01%). Changes in Haugh unit (HU) values, weakening of vitelline membranes, and generation of volatiles were analyzed to evaluate the freshness of shell eggs. Results showed that, compared with the other combinations, the technique of super chilling and high carbon dioxide concentration enabled shell eggs to be most effectively stored for 90 d, based on estimations of the statistical significances of differences in HU values, and on maintaining the initial HU values during storage. In addition, the storage of shell eggs using this combination technique was found to significantly prevent the weakening of the vitelline membrane based on the estimations of numbers of eggs without vitelline membrane breakage when eggs broke, and significantly lowered the incidence of hexanal in the yolk from exposure to the gas chromatographic-mass spectrometric analyses of volatiles. Thus, these results confirmed that the combination of super chilling and high carbon dioxide concentration was the most effective technique for preserving shell eggs during a long term of 90 d compared with other combination techniques. [source] The influence of different single dietary sources on moult induction in laying hensJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2007Behzad Mansoori Abstract An investigation was carried out to assess the possibility of using single dietary sources as alternatives to feed deprivation for the induction of moult in commercial laying hens. The study involved six dietary groups of 29 laying hens: unmoulted, dried tomato pomace, alfalfa meal, rice bran, cumin seed meal and feed withdrawal. The birds received the above diets during the moulting period (11 days), and body weight loss and ovary weight regression were measured. Post-moult production parameters (number of eggs produced per hen per day, egg weight, shell weight, yolk colour and Haugh unit) were measured for 12 weeks. Results showed that all dietary sources were as effective as feed withdrawal in causing ovary weight regression in birds. Birds provided with tomato pomace or alfalfa showed lower weight losses than feed-deprived birds at the end of the moulting period. Hens moulted by tomato pomace or alfalfa exhibited post-moult levels of egg production over a 12 week period that were superior to those of hens moulted by feed withdrawal. Post-moult eggs laid by hens moulted by all dietary sources were of comparable quality to eggs from feed-deprived hens and superior to those from unmoulted hens. As fibrous feeds with low metabolisable energy and an appreciable amount of protein, dried tomato pomace and alfalfa meal may be fed to hens on an ad libitum basis for effective moult induction while reducing the stress of severe starvation and retaining comparable egg quality and production. Copyright © 2007 Society of Chemical Industry [source] Whey protein isolate coating and concentration effects on egg shelf lifeJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2005Cengiz Caner Abstract The influences of three different concentrations (6, 12 and 18%) of whey protein isolate (WPI) coatings on shelf-life enhancements of the fresh egg quality (weight loss, pH, Haugh unit, yolk index and colors) and the shelf life were evaluated at room temperature. All coated eggs showed lower weight loss than uncoated eggs. Less weight loss (2.46 for 12% WPI and 2.38 for 18% WPI) was observed in WPI-coated eggs. Haugh units (HU) indicated that coated eggs remained in grade ,A' during 3 weeks storage period, whereas uncoated (UC) changed from grade ,A' to ,B' after 1 week of storage. The HU and yolk-index (YI) values of all WPI-coated eggs were significantly higher than those of UC. Among the coated eggs, there were no significant differences in HU, but 12 and 18% WPI coated had higher YI than WPI 6% coated and UC. The albumen pH of the UC eggs was significantly higher than that of coated eggs. Yolk lightness (L*) and (b*); shell (a*) and (b*) of coated eggs were not different from UC after 4 weeks. Performance of WPI coatings depended on the concentration up to 12% but not between 12 and 18%. Results also indicated that WPI coatings served as protective barrier for shelf life of the eggs. Copyright © 2005 Society of Chemical Industry [source] Spontaneous Spawning of Captive Red Snapper, Lutjanus campechanus, and Dietary Lipid Effect on Reproductive PerformanceJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2008Nikolaos Papanikos Two experiments addressed the spontaneous spawning of red snapper, Lutjanus campechanus, under controlled temperatures and photoperiods and the effect of broodstock diets supplemented with oils rich in polyunsaturated fatty acids. In Experiment 1, broodfish were fed a standard diet (ST1) and one enriched with menhaden oil (ER1) over a 355-d period. ER1-influenced egg fatty acid profile, however, did not positively influence egg production. Both diets produced highly viable eggs and larvae but results varied within treatments. In Experiment 2, broodfish were fed either a standard diet (ST2) or one supplemented with oils (ER2) rich in docosahexaenoic and arachidonic acid using a 203-d cycle. Both treatments produced eggs but fertilization rates ranged 0,10%. There was no clear influence of the diets on egg fatty acid profiles. These results indicate that red snapper can spawn spontaneously in tanks under controlled environmental conditions and produce viable eggs and larvae when fed diets based on squid, shrimp, and fish. The fatty acid composition of the diets was reflected in the eggs to some degree, but the oil enrichments did not further enhance the reproductive performance and egg quality under the conditions of this study. [source] Sustained, Natural Spawning of Southern Flounder Paralichthys lethostigma Under an Extended Photothermal RegimeJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2001Wade O. Watanabe Hormone-induced spawning of southern flounder Paralichthys lethostigma has produced substantial numbers of viable eggs, but wide variations in fertilization and hatch rates have been reported. Recently, sustained natural spawning of southern flounder broodstock, without hormone induction, has been achieved in our laboratory. Adults (average weight = 1.12 kg; N= 25), including 6 captured as juveniles in 1993 and 19 captured as adults during September 1998, were stocked in two 4.8-m3 controlled-environment tanks in October 1998 and held under natural photothermal conditions until January 1999, when an artificial winter photo-period of 10 L:14 D was initiated and then maintained through April 1999. Sex ratio was approximately 13 females:8 males:7 unknown. Natural spawning was observed in early December 1998 and increased in frequency to a peak in March 1999, before declining in late April. Water temperature ranged from 13.9 to 24.5 C during the spawning period. Natural spawnings over 142 d produced a total of 18.3 × 106 eggs, with a mean fertilization rate of 28.0% (range = 0,100%), yielding 4.94 × 106 fertilized eggs. The mean percentage of eggs that remained buoyant in full-strength seawater (34 ppt) was 41.3% (0,98%), while hatching rate of buoyant eggs was 37.3% (0,99%) and survival of yolksac larvae to the first-feeding stage was 30.2% (0,100%). Gonadal biopsies in late April identified six females from both tanks as probable spawners. A preliminary comparison suggests that natural spawning produced much larger numbers of viable eggs per female, with higher egg quality (i.e., fertilization and hatching success) than hormone-induced spawning. In contrast to natural spawning, hormone-induced strip-spawning enabled timing of spawnings to be more precisely controlled. These results suggest that a combination of both natural and hormone-induced spawning of photothermally conditioned fish will help produce the large numbers of eggs required to support commercial production. [source] Polymorphisms in vitamin D receptor, osteopontin, insulin-like growth factor 1 and insulin, and their associations with bone, egg and growth traits in a layer , broiler cross in chickensANIMAL GENETICS, Issue 3 2006A. K. Bennett Summary Bone strength traits in chickens are gaining importance due to economic losses and welfare concerns associated with bone fractures and other abnormalities. A chicken F2 resource population was generated from layer and broiler genetic lines, and traits relating to bone strength, egg production, egg quality and growth rate were measured in approximately 500 F2 hens. Four biological candidate genes (vitamin D receptor, VDR; insulin, INS; insulin-like growth factor 1, IGF1; and osteopontin, SPP1) were selected for investigation. Single nucleotide polymorphisms (SNPs) were identified for each candidate gene by comparing sequences between grandparent lines. Polymerase chain reaction restriction-fragment length polymorphism or SNaPshot assays were developed to genotype the F2 population and to evaluate associations between each SNP genotype and multiple phenotypes. Significant associations (P < 0.0125) were found between VDR and bone mineral content of the humerus at 35 weeks of age; between IGF1 and SPP1 and 5-week body weight; and between INS and 55-week body weight. [source] Identification of quantitative trait loci associated with egg quality, egg production, and body weight in an F2 resource population of chickens,ANIMAL GENETICS, Issue 2 2006M. A. Schreiweis Summary Egg production and egg quality are complex sex-limited traits that may benefit from the implementation of marker-assisted selection. The primary objective of the current study was to identify quantitative trait loci (QTL) associated with egg traits, egg production, and body weight in a chicken resource population. Layer (White Leghorn hens) and broiler (Cobb-Cobb roosters) lines were crossed to generate an F2 population of 508 hens over seven hatches. Phenotypes for 29 traits (weekly body weight from hatch to 6 weeks, egg traits including egg, albumen, yolk, and shell weight, shell thickness, shell puncture score, percentage of shell, and egg shell colour at 35 and 55 weeks of age, as well as egg production between 16 and 55 weeks of age) were measured in hens of the resource population. Genotypes of 120 microsatellite markers on 28 autosomal groups were determined, and interval mapping was conducted to identify putative QTL. Eleven QTL tests representing two regions on chromosomes 2 and 4 surpassed the 5% genome-wise significance threshold. These QTL influenced egg colour, egg and albumen weight, percent shell, body weight, and egg production. The chromosome 4 QTL region is consistent with multiple QTL studies that define chromosome 4 as a critical region significantly associated with a variety of traits across multiple resource populations. An additional 64 QTL tests surpassed the 5% chromosome-wise significance threshold. [source] Effect of dietary dried milky sludge on productive performance and egg quality in laying Japanese quailsANIMAL SCIENCE JOURNAL, Issue 3 2009Tawadchai SUPPADIT ABSTRACT The experiment was conducted to study the effectiveness of dried milky sludge (DMS) as a feed source for laying Japanese quails. The DMS was incorporated into the experimental diets at levels of 0, 5.0, 10.0, 15.0 and 20.0%. Four hundred quails were used in a completely randomized design. The results revealed that the daily egg-laying rate, feed cost/100 egg weight, egg width, egg length, egg weight, shell quality characteristics in terms of breaking time, Young's modulus, work, max force, fracturability, breaking stress, stiffness and power, as well as color intensity and yolk height improved significantly with increasing levels of DMS in the diet (P < 0.05), while feed intake/bird/day, mortality and eggshell thickness showed no significant differences (P > 0.05). From this experiment, it was found that DMS incorporated into the experimental diet at the 20.0% level yielded the most productive performance and best egg quality. [source] Influence of forage fish and dietary lipid supplements on egg quality and fry production in channel catfish (Ictalurus punctatus) × blue catfish (Ictalurus furcatus) hybridizationAQUACULTURE NUTRITION, Issue 2 2010E.R. DURLAND Abstract Hybrid catfish (channel catfish Ictalurus punctatus × blue catfish Ictalurus furcatus) display characteristics that are favourable to aquaculture production. Low hatch percentages are a principal reason this hybrid is not used widely in the catfish industry. This study was conducted to determine whether additional food source rich in lipids may lead to a higher quality egg production. A 10-week feed trial was conducted in ponds in Auburn, AL. A total of 219 female Kansas Select channel catfish were stocked into nine ponds, 0.04 ha in size. Three dietary treatments were randomly allocated to the ponds. Diet-1 was a standard 60 g kg,1 lipid floating catfish feed. Diet-2 was the same feed supplemented with forage fish at ,28 kg ha,1. The third diet was the aforementioned catfish feed topcoated with 20 g kg,1 lipid [10 g kg,1 menhaden fish oil, 5 g kg,1 high docosahexaenoic acid (DHA) oil and 5 g kg,1 high arachidonic acid oil]. Results indicate that brood fish fed the high lipid diet spawned larger egg masses and had larger eggs both in weight and in diameter, with increased complements of fatty acids such as DHA, eicosapentaenoic acid and total n-3 fatty acids. The neutral and polar lipid fractions are also presented. [source] Dietary n-3/n-6 ratio affects the biochemical composition of Eurasian perch (Perca fluviatilis) semen but not indicators of sperm qualityAQUACULTURE RESEARCH, Issue 9 2010Emilie Henrotte Abstract In general, the effects of dietary fatty acids (FA) on sperm quality have received less attention than egg quality, and were never studied in perch. This study investigated the effects of dietary FAs on the quality and chemical composition of sperm in Eurasian perch (Perca fluviatilis). Two experimental diets containing 16% lipids and 45% proteins were compared. The n-3/n-6 ratios tested were 0.2 for diet 1 (D1) and 7.0 for diet 2 (D2). No significant effects of the n-3/n-6 ratio were observed on the sperm characteristics, either in terms of the sperm volume (around 1.2 mL) and density, spermatozoa motility (94%) and velocity, or the sperm osmolality. All these parameters corresponded to semen of good quality in Eurasian perch. Interestingly, both the FA composition and the lipid class profile of the semen were correlated to the tested diet. However, basal levels of certain highly unsaturated FAs such as eicosapentaenoic acid, 20:5 n-3 and docosahexaenoic acid, 22:6 n-3, were maintained in the sperm irrespective of the diet tested. Perch semen was characterized by high levels of cholesterol, phosphatidylethanolamine and phosphatidylcholine. In conclusion, the dietary n-3/n-6 ratio affects the lipid composition of perch semen but not the indicators of sperm quality. [source] Induced ovulation of yellow catfish (Pelteobagrus fulvidraco) using a combination of a gonadotrop-releasing hormone analogue and domperidoneAQUACULTURE RESEARCH, Issue 8 2010Youji Wang Abstract The effects of an intraperitoneal hormone injection of gonadotropin-releasing hormone agonist (D-Ala6, Pro9 -NEt GnRHa) alone or in combination with a dopamine antagonist, domperidone (DOM), on ovulation induction in yellow catfish Pelteobagrus fulvidraco were tested. The hormone treatments were as follows: 6 mg kg,1 body weight (BW) of carp pituitary extract as a positive control, GnRHa 10, 20, 40 and 80 ,g kg,1 BW and a combination of GnRHa and DOM as follows: 10 ,g+5 mg, 20 ,g+10 mg, 40 ,g+20 mg and 80 ,g+40 mg kg,1 BW. Physiological saline (0.7% NaCl) was used as a negative control. Significant differences in the ovulation ratio, latency period and ovulation index (OI) were observed among treatments (P<0.05). The combination of GnRHa and DOM at doses of 40 ,g+20 mg kg,1 BW had higher values of the ovulation ratio and OI, and a shorter latency period compared with other treatments. The highest OI in GnRHa treatments was only 56.67%, suggesting a dopaminergic tone on gonadotropin secretion in this fish at the pre-ovulatory stage. Therefore, ovulation can be successfully induced in yellow catfish with 40 ,g kg,1 GnRHa+20 mg kg,1 DOM without affecting the egg quality. [source] LHRHa-induced ovulation of the endangered-Caspian brown trout (Salmo trutta caspius) and its effect on egg quality and two sex steroids: testosterone and 17,-hydroxyprogestroneAQUACULTURE RESEARCH, Issue 6 2010Ahmad Noori Abstract To induce synchronized ovulation, migrating wild Caspian brown trout (Salmo trutta caspius) females were treated with two interperitoneal injections of Des-Gly10, d -Ala6 LHRH (LHRHa), given 3 days apart. Two injections of 100 ,g kg,1 body weight of this hormone effectively induced ovulation. Within 27 days from the second injection, all fish injected with 100 ,g kg,1 LHRHa had ovulated compared with 54.5% of the controls. The mean time to ovulation was reduced significantly (P<0.05) from 31.67±4.84 days in control fish and 28.83±7.31 days in sham-treated fish to 16.36±1.61 days in fish injected with 100 ,g kg,1 LHRHa. The fertilization rate in 50 and 100 ,g kg,1 LHRHa-injected fish was significantly lower than that in the control fish (P<0.05). In fish injected with 50 and 100 ,g kg,1 LHRHa, significant (P<0.05) changes in testosterone (T) and 17,-hydroxyprogestrone (OHP) levels were observed. After the second LHRHa injection, the fish injected with 100 ,g kg,1 showed the highest serum levels of testosterone and OHP. These results demonstrate that the use of LHRHa can effectively reduce the mean time to ovulation and induce synchronized ovulation in Caspian brown trout. [source] Spawning induction of pejerrey Odontesthes bonariensis in captivity using sustained-release gonadotropin releasing hormone agonist implantsAQUACULTURE RESEARCH, Issue 1 2009Leandro A. Miranda Abstract The aim of this study was to induce and synchronize spawning of pejerrey Odontesthes bonariensis (Valenciennes, 1835), using gonadotropin releasing hormone agonist (GnRHa) implants. In the first experiment, the ovarian condition was assessed by ovarian biopsies and the measurement of the genital pore width (GPW). Females having the leading clutch of oocytes with a diameter of around 800,900 ,m and a GPW between 4.5 and 5.5 mm were treated with GnRHa implants. Eighty per cent of females spawned between 2 and 9 days after treatment, 12 days earlier than 20% of the fish in the control group that presented signs of spawning activity. In order to avoid any possible ovarian injury and/or stress by the catheterization procedure, in a second experiment, females were selected only by visual inspection of the abdomen and GPW measurement. As in experiment 1, 80% of females spawned between 2 and 8 days after treatment, 8 days earlier than 30% of the fish that spawned in the control group. In both experiments, fertilization and hatching success were similar between control and GnRHa-treated groups. These results clearly demonstrated that GnRHa implantation can advance and synchronize ovulation and spawning in pejerrey without affecting egg quality. [source] Preliminary investigations on the effects of dietary lipid on the spawning performance and egg quality of black sea bass Centropristis striata LAQUACULTURE RESEARCH, Issue 16 2009Christopher D Bentley Abstract Adult black sea bass Centropristis striata broodstock (N=162) were fed three different dietary treatments: two commercially prepared diets with 45% protein and two different lipid levels (12% and 20%) (diets 1 and 2), and a diet of frozen Atlantic silversides Menidia menidia (SS, diet 3). Broodstock were held under controlled photothermal conditions and induced to spawn with an LHRHa pellet (72 ,g kg,1 bw). Dietary lipid had pronounced effects on spawning performance and egg quality. Diet 3 (SS) produced a significantly (P<0.05) higher fertilization success (22.4%) than diets 1 (0.6%) and 2 (4.8%). The hatching success of fertilized eggs was similar in all diets (range=40,58.6%), but only two spawns from diet 1 (12% lipid) yielded viable yolk-sac larvae (YSL). Diet 3 (SS) also produced significantly more YSL per female (21.8 × 103) than the diet 1 (0.3 × 103). Eggs from diet 3 (SS) contained a significantly greater proportion of n-3 series fatty acids, with docosahexaenoic acid (DHA) as the largest fraction. Eggs from commercially prepared dietary treatments contained significantly more n-6 fatty acids. The poor spawning performance of fish fed diet 1 (12% lipid) may be related to higher levels of linoleic acid and lower levels of DHA in the diet. [source] Investigation of the temporal effects of spawning season and maternal and paternal differences on egg quality in Atlantic cod Gadus morhua L. broodstockAQUACULTURE RESEARCH, Issue 14 2009Dounia Hamoutene Abstract A better understanding of the parameters affecting egg quality and larval survival is of importance for continued development of cod broodstock and efficient husbandry practices. Decision tree analysis (DTA) was applied to analyse 3 years of egg quality data in an effort to extract the most important variables (i.e. predictors) in explaining differences in egg quality. The effect of three predictors (spawning time, maternal and paternal differences) has been studied on early cleavage pattern parameters, egg diameters, fertilization and hatching rates and has shown that females are the dominant variable and that time has a limited and inconsistent impact on the data. When using maternal, paternal differences and batch number (instead of spawning time) as predictors, the results confirm that no particular relationship is found between batch order (i.e. order in time) and egg quality. Moreover, batches with a higher egg quality show a consistency in the parameters assessed (i.e. batches with higher rates of normality in any parameter tend to be normal for other parameters). This is confirmed by the significant correlations found between cleavage parameters. Our results highlight that spawning time is of less importance than female parent contribution in ensuring high rates of fertilization and larval hatch, and maximizing general egg quality. [source] Vitamin contents of eggs that produce larvae showing a high survival rate in the Japanese eel Anguilla japonicaAQUACULTURE RESEARCH, Issue 11 2009Hirofumi Furuita Abstract This paper describes the relationship between the egg vitamin concentrations and the egg quality in the Japanese eel Anguilla japonica. No notable relation was found between any vitamin and the fertilization rate. Hatching and survival rates of larvae, however, significantly increased with an elevated level of egg vitamin C (VC). In contrast to VC, the relation between vitamins E (VE) and A (VA) concentrations and survival rate showed a clear peak, with a reduced survival rate at both higher and lower vitamin concentrations. The ratio of VE to lipid or highly unsaturated fatty acid (HUFA) in eggs positively correlated with hatching and survival rates of larvae. High-quality (HQ) eggs were determined as eggs that produced larvae having a survival rate higher than 80% at 8 days post hatch, and low-quality (LQ) eggs were determined as eggs that did not hatch. The level of VC of HQ was significantly higher than LQ. The results of this study suggest that HQ eggs, which produce larvae having a high survival rate, must have high levels of VC and VE/HUFA ratio and contain optimum levels of VA and VE in Japanese eel. [source] First results on a relation between ovarian fluid and egg proteins of Salmo trutta and egg qualityAQUACULTURE RESEARCH, Issue 2 2007Franz Lahnsteiner Abstract By use of sodium dodecyl sulfate polyacrylamide gel electrophoresis, ovarian fluid proteins and main proteins of unfertilized eggs were qualitatively and quantitatively investigated in the brown trout, Salmo trutta, to see whether some of them were correlated with the rate of embryos reaching the eyed embryo stage. In the ovarian fluid, 12 types of proteins in the range of 39,166 kDa were detected whereby three proteins were lipoproteins and two were glycoproteins. Ovarian fluid proteins with a molecular weight of 85, 68, 62 and 39 kDa were negatively correlated with the percentage of eyed stage embryos. The statistical significance of the relations was low in simple and multiple regression models (R2,0.534) indicating that the relations were influenced and superposed by other factors. Therefore, ovarian fluid proteins give only poor information about maturity and quality of eggs. In the eggs, nine major types of proteins in the range of 95,15 kDa were identified. The 95 kDa protein was a lipoprotein, the 85 and the 62 kDa protein were glycoproteins, and the 15 kDa protein was a phosphoprotein. The 95, 85, 77 and 39 kDa protein were positively correlated with embryo survival to the eyed embryo stage. The explanatory effect of the multiple regression model was very high (R2=0.961) indicating that distinct egg proteins are closely related with egg quality. [source] Influence of dietary protein levels on growth and egg quality in broodstock female bagrid catfish (Mystus nemurus Cuv.AQUACULTURE RESEARCH, Issue 4 2006& Val.) No abstract is available for this article. [source] Induced spawning of Asian catfish, Clarias batrachus (Linn.): effect of various latency periods and SgnRHa and domperidone doses on spawning performance and egg qualityAQUACULTURE RESEARCH, Issue 15 2005Article first published online: 2 NOV 200 No abstract is available for this article. [source] Capture and handling stress affects the endocrine and ovulatory response to exogenous hormone treatment in snapper, Pagrus auratus (Bloch & Schneider)AQUACULTURE RESEARCH, Issue 11 2002J J Cleary Abstract Sexually mature female hatchery-reared snapper, Pagrus auratus (Bloch & Schneider) were captured from sea cages by handline and injected at first capture (control) or 24 h after capture, transport and subsequent confinement (delayed injection) with either saline, luteinizing hormone releasing hormone analogue, human chorionic gonadotropin, or 17,-hydroxyprogesterone. Blood was sampled before hormone treatment and again after 168 h, and fish were checked daily for ovulation. Plasma levels of 17,-estradiol (E2), testosterone (T), 17,, 20, dihydroxy-4-pregnen-3-one (17, 20,P) and cortisol were determined by radioimmunoassay. The ovulatory response was assessed from the proportion of fish ovulating, ovulation volume, egg quality and fertility. A delay in injection resulted in significantly lower plasma E2 and T levels in response to hormone treatment, smaller ovulation volumes, and poorer egg quality than in control fish. The results are consistent with the generally inhibitory effects of stress on reproduction in fish, and confirm the requirement to treat fish with hormones designed to induce ovulation, as soon as possible after capture and disturbance. [source] | ||||||||||||||||