نتایج جستجو برای: egg hatching rate
تعداد نتایج: 1004819 فیلتر نتایج به سال:
Despite the reported effects of egg vitellogenin-derived proteins (VtgDP) and amino acids on embryo-larvae viability in common dentex the effects of non-vitellogenin-derived proteins (non-Vtg-DP) has yet to be determined. As an initial study, fertilized eggs (70 batches) were provided by natural spawning of broodfish in captivity. Viability parameters (VP) such as egg floating, hatching, and la...
In order to reduce the adverse effects of sexual maturation on growth and survival of rainbow trout, production possibility of all-female triploid was investigated by means of early heat shock on eggs fertilized by masculinized male’s sperm. Fish ploidy level was determined by erythrocyte size measurement and confirmed by gill nucleolus (NORs) counting as well as chromosome number. Sexual ratio...
In this study, rainbow trout (Oncorhynchus mykiss) eggs were treated with effective doses of Daenensis thyme, Thymus daenensis (20, 10 and 5 mgL-1) and Mentha, Mentha longifolia (10, 5 and 2.5 mgL-1), during incubation period (20 days) until hatching for 30 minutes per every other day as constant flow bath treatment method. The mortality level in normal control (without any treatment) was sign...
We studied the onset of incubation in the Green-rumped Parrotlet (Forpus passerinus), a cavity-nesting species with female-only incubation starting on the first egg and asynchronous hatching. We quantified how the onset of incubation varied among individual females, with stage of egg-laying and by ultimate clutch size. We then examined whether this variation affected the incubation period and h...
BACKGROUND The aim of his study was to determine development time and thermal requirements of three myiasis flies including Chrysomya albiceps, Lucilia sericata, and Sarcophaga sp. METHODS Rate of development (ROD) and accumulated degree day (ADD) of three important forensic flies in Iran, Chrysomya albiceps, Lucilia sericata, and Sarcophaga sp. by rearing individuals under a single constant ...
Plasticity in hatching timing allows embryos to balance egg- and larval-stage risks, and depends on the ability of hatching-competent embryos to continue developing in the egg. Hypoxia can slow development, kill embryos and induce premature hatching. For terrestrial eggs of red-eyed treefrogs, the embryonic period can extend approximately 50% longer than development to hatching competence, and ...
Both parental care and hatching plasticity can improve embryo survival. Research has found that parents can alter hatching time owing to a direct effect of care on embryogenesis or via forms of care that cue the hatching process. Because parental care alters conditions critical for offspring development, hatching plasticity could allow embryos to exploit variation in parental behaviour. However...
Penetration of the hatching egg shell by microorganisms results in embryonic mortality, weak chicks, high chick mortality, and poor chick growth. The most effective sanitation system involves treating the eggs as soon as they are collected from the nest and before microorganisms penetrate the shell. Several recent research studies have examined the effectiveness, safety and ease of use of commo...
the aims of this study were to investigate the effect of photoperiod and light intensity on egg production and hatching rate in acartia clausi in laboratory conditions. this zooplankton was collected from caspian coastal waters of mazandaran province by the use of a 100µ net. all tests were performed in five light treatments (photoperiod) namely 24:00, 18:06, 12:12, 06:18, 00:24 (light / dark),...
Intraspecific variation in egg size and hatching size, and the genetic and environmental trade-offs that contribute to variation, are the basis of the evolution of life histories. The present study examined both univariate and multivariate temperature-mediated plasticity of life-history traits, as well as temperature-mediated trade-offs in egg size and clutch size, in two planktotrophic species...
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