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Effects of dietary genistein administration on growth,survival and sex determination in southern flounder,Paralichthys lethostigma 
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下载免费PDF全文 Matthew A DiMaggio Linas W Kenter Timothy S Breton David L Berlinsky 《Aquaculture Research》2016,47(1):82-90
The inclusion of soybean meal and soy concentrates in finfish feeds may introduce endocrine disrupting compounds in the form of phytoestrogens. Genistein, which may dually act as an oestrogen receptor agonist/antagonist, has been shown to elicit both masculinizing and feminizing effects in several teleost species. The objective of this investigation was to examine the effects of dietary genistein administration on reproductive development, growth and survival in southern flounder (Paralichthys lethostigma). Southern flounder received one of three experimental diets which contained varying concentrations of genistein (control – 0, low dose –100 and high dose –1000 mg genistein kg?1 feed) from 84 to 153 days post hatch (DPH). Fish remained in culture until 285 DPH at which time sex ratios were determined. Growth and survival were evaluated at 153 and 285 DPH. Greater numbers of female fish resulted from the low and high dose genistein treatments (98 ± 2% and 78 ± 12% respectively), as compared to the control group (21 ± 10%). Reduced growth at 153 DPH and poor survival (28%) at 285 DPH were also observed for the high dose genistein treatment. Collectively, these results demonstrate the feminizing effects of genistein in southern flounder, but reduced growth and survival with high dietary administration. 相似文献
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Ivan BALÁŽ Michał BOGDZIEWICZ Sylwia DZIEMIAN-ZWOLAK Carlotta LO PRESTI Aleksandra WRÓBEL Milena ZDUNIAK Rafał ZWOLAK 《Integrative zoology》2023,18(3):440-452
Mast seeding causes strong fluctuations in populations of forest animals. Thus, this phenomenon can be used as a natural experiment to examine how variation in host abundance affects parasite loads. We investigated fleas infesting yellow-necked mice in beech forest after 2 mast and 2 non-mast years. We tested 2 mutually exclusive scenarios: (1) as predicted by classical models of density-dependent transmission, an increase in host density will cause an increase in ectoparasite abundance (defined as the number of parasites per host), versus (2) an increase in host density will cause a decline in flea abundance (“dilution,” which is thought to occur when parasite population growth is slower than that of the host). In addition, we assessed whether masting alters the relationship between host traits (sex and body mass) and flea abundance. We found a hump-shaped relationship between host and flea abundance. Thus, the most basic predictions are too simple to describe ectoparasite dynamics in this system. In addition, masting modified seasonal dynamics of flea abundance, but did not affect the relationship between host traits and flea abundance (individuals with the highest body mass hosted the most fleas; after controlling for body mass, parasite abundance did not vary between sexes). Our results demonstrate that pulses of tree reproduction can indirectly, through changes in host densities, drive patterns of ectoparasite infestation. 相似文献
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Grape growers may occasionally face difficulties in grape skin coloration and low total soluble solids content in growing of early ripening table grape cultivars. In order to overcome these difficulties, it can be utilized from foliar biostimulants treatments. The purpose of this study, carried out 2015 growing season in Tekirda?, Turkey, was to compare the effects of doses of two different biostimulants, enhancing table grape quality characteristics of cv. Tarsus Beyaz?, cv. Trakya Ilkeren and cv. Yalova Incisi. For this aim, it was focused on three different doses for both biostimulants, including 0, 1750 and 3500?ppm (respectively, Control, BSt A-1 and BSt A-2) for first biostimulant and 0, 3500 and 4500?ppm (respectively, Control, BSt B-1 and BSt B-2) for second biostimulant. As a result, present research demonstrated that BSt B-2 and BSt A-2 treatments especially enhanced most of table grape quality characteristics in cv. Tarsus Beyaz?, cv. Trakya Ilkeren and cv. Yalova Incisi. 相似文献
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Linas BALIAUSKAS Albina AMSHOKOVA Laima BALIAUSKIEN&#x; Ana Maria BENEDEK Jan CICHOCKI Alexander CSANDY Philippe Gil DE MENDONA Victoria NISTREANU 《Integrative zoology》2020,15(1):55-68
Patterns of body size variation along geographical gradients have long been searched for and generalized into eco‐geographical rules. However, no rodent species has yet been analyzed in relation to the 3 dimensions of latitude, longitude and altitude. We analyzed geographical clines and dimorphism of body and skull size in the herb field mouse (Apodemus uralensis) across the species range, based on field data and on data from the literature. Sexual dimorphism in adult A. uralensis was not expressed at a large scale, while local patterns were inconsistent. Age‐dependent size changes were most expressed in adult individuals: most characters of adults exceeded in size those of subadults, while subadult–juvenile size differences were only significant in body weight and length, zygomatic skull width, length of cranial diastema and breadth of braincase. Despite central morphological niches along the clines being separated, A. uralensis populations showed a high degree of size overlap in morphological space. We found the species to be characterized by high size variability, with the largest individuals inhabiting the eastern and southern edges of the distribution range. Tail, hind foot and ear lengths were largest in the southern part of the range, in agreement with Allen's rule. The main measurements that we analyzed, namely body mass, zygomatic skull width and condylobasal skull length, show the presence of 3 clines in the size of adult A. uralensis: (i) a decreasing south–north cline, opposing Bergmann's rule; (ii) an increasing west–east cline, in accordance with Murphy's rule; and (iii) an increasing altitudinal cline. 相似文献
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Des 1980, la résistance aux imides cycliques (I. C.) s'est généralisée dans les populations de Botrytis cinerea sur fraisiers remontants, traités de 3 à 10 fois de juillet à septembre avec des I. C., le taux moyen de fraises présentant des conidies résistantes étant de 72%. Une diminution progressive du taux de résistance est observée après l'arrêt des traitements, mais est suivie d'une forte augmentation 5 à 6 semaines apres la reprise des traitements l'année suivante. L'efficacité des traitements à la vinchlozoline (500 g ha?1) est passée de 94%, pour les essais de 1973 à 1978, à 48% pour ceux établis de 1979 à 1984. Durant cette derniére période, le mélange vinchlozoline (500 g ha?1)+ thirame (1600 g ha?1) a présenté une efficacité de 78% et le tolylfluanide a donné une efficacité de 67%. Sur fraisiers de saison, traités 1 à 6 fois au moment de la floraison, une résistance aux I. C. a été observée en 1980 dans sept des 10 champs analysés, avec un taux moyen de 22%. La résistance ne s'y développe que tardivement et principalement dans les cultures de 2 ans, traitées déjà l'année précédente avec des I. C. Dans les essais, l'efficacité de la vinchlozoline s'est maintenue á 92% entre 1973 et 1984. 相似文献
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Abstract. A non-lymphocystis type disease associated with virus particles has been documented in winter flounder, Pseudopleuronectes americanus (Walbaum), taken from a small estuary in Conception Bay, Newfoundland. The papillomatosis-type lesions found on the dorsal surface of the fish contained numerous electron-dense particles, approximately 30 nm in diameter. A number of lines of evidence, including cytochemical studies, indicated that the particles were not glycogen but virions. Sensitivity to deoxyribonuclease enzyme treatment and the presence of crystalline viral'factories' in the nuclei of infected cells further suggested that the particles were small DNA virions. Characteristics including nucleic acid composition, particle size, site of multiplication and the lack of an envelope indicate that this fish virus is similar to the Papovaviridae and Parvoviridae families of mammalian viruses. Lymphocystis is common in flatfish populations along the Newfoundland and Labrador coasts of the N.W. Atlantic, but this is the first record of flatfish infection with a small DNA virus. 相似文献
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