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(接《新饲料》第10期第14页)2针对食品安全进行饲料的营养调控2.1霉菌毒素的控制霉菌毒素是最重要的饲料污染物之一,并且会给动物以及公众健康带来严重影响。霉菌毒素有多种危 相似文献
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Haerens L Cerin E Maes L Cardon G Deforche B De Bourdeaudhuij I 《Public health nutrition》2008,11(5):501-512
OBJECTIVE: The aim of the present study was to examine the mediation effects of changes in psychosocial determinants of physical activity (attitude, social support, self-efficacy, perceived benefits and barriers) on changes in physical activity. DESIGN: One-year intervention study with baseline and 1-year post measures of physical activity habits and psychosocial correlates. SETTING: Fifteen middle schools. SUBJECTS: Boys and girls (n = 2840) aged 11-15 years completed the validated questionnaires during class hours. RESULTS: The product-of-coefficients test was used to asses the mediating effects. Self-efficacy for physical activity at school was found to be the only significant mediator of physical activity change. Specifically, self-efficacy for physical activity at school partly mediated the effect of the intervention on total and school-related physical activity change in the intervention group with parental support (P < 0.05). None of the other potential mediators, attitudes, social support, perceived benefits and perceived barriers, seemed to have had a positive effect. Even a suppressor effect was found for attitudes. Given that the effects of self-efficacy and attitudes were of opposite direction, the total mediated/suppressed effects of the intervention were not statistically significant. CONCLUSIONS: Positive changes in total and school-related physical activity in adolescents could be partly explained by increases in self-efficacy for physical activity at school through a physical activity intervention in middle schools with parental support. However, the suppressor effect of attitudes decreased this effect. As this is one of the first true mediation analyses in this age group, further research is needed to replicate the importance of these mediators. 相似文献
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Timbermont L Lanckriet A Gholamiandehkordi AR Pasmans F Martel A Haesebrouck F Ducatelle R Van Immerseel F 《Comparative immunology, microbiology and infectious diseases》2009,32(6):503-512
Since the ban on growth-promoting antibiotics in animal feed in the European Union, necrotic enteritis has become a major cause of mortality in broiler chickens. Despite the importance of the disease, the pathogenesis is still not completely understood. In the current study, Clostridium perfringens strains isolated from healthy flocks and isolates from outbreaks of necrotic enteritis were evaluated for the ability to cause gut necrosis in an intestinal loop model in laying hens and in an experimental infection model in broilers. High, intermediate and low alpha toxin producing strains were chosen from each isolation source. Only the isolates from field outbreaks induced necrotic gut lesions, independent of the amount of alpha toxin produced in vitro. It was also shown that alpha toxin producing isolates from calf hemorrhagic enteritis cases were not able to induce necrotic enteritis in poultry. These results suggest the presence of host specific virulence factors in C. perfringens strains, isolated from chickens with intestinal necrotic enteritis lesions. 相似文献
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Helleborus species are members of the family of the Ranunculaceae. These popular perennials are all diploids (2n = 2x = 32). This study investigates polyploidy induction by different antimitotic agents. Colchicine, oryzalin and trifluralin
were tested in vitro on shoots of Helleborus niger, H. orientalis and H. × nigercors. Furthermore the effect of the antimitotic agents on the viability and the multiplication rate of cultured plantlets were
analyzed. Flow cytometry demonstrated that polyploidisation was genotype dependent: using H. niger, tetraploids were obtained using either oryzalin (3 μM) or trifluralin (3 or 10 μM), whereas for H. × nigercors only trifluralin (3 or 10 μM) induced polyploidisation. For H. orientalis neither treatment was effective to produce tetraploids or mixoploids. For these three species, colchicine (100 μM) was ineffective.
The polyploidisation events in H. niger and H. × nigercors were confirmed by chromosome counts of mounted nuclei derived from root tips (2n = 4x = 64). 相似文献
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Chen D Yu S van Ofwegen L Proksch P Lin W 《Journal of agricultural and food chemistry》2012,60(1):112-123
Fifteen new guaiazulene-based terpenoids designated anthogorgienes A-O (1-15) were isolated from a Chinese gorgonian Anthogorgia sp., together with eight known analogues (16-23). The structural patterns were classified into monomers, dimers, and trimers, which were supposed to be generated from a precursor guaiazulene and followed by side-chain and nucleus oxidation and oxidative rearrangement. The structures of new compounds were elucidated on the basis of extensive spectroscopic (IR, MS, and 1D and 2D NMR) data analysis. A possible biogenetic relationship of the isolated compounds was postulated. Some of the compounds showed potent antifouling activities against the larval settlement of barnacle Balanus amphitrite , whereas their antibiotic activities were also evaluated. 相似文献
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Proaño-Pérez F Benitez-Ortiz W Desmecht D Coral M Ortiz J Ron L Portaels F Rigouts L Linden A 《Preventive veterinary medicine》2011,101(1-2):65-72
Veterinary inspection in slaughterhouses allows for the detection of macroscopic lesions reminiscent of bovine tuberculosis, but the presence of Mycobacterium bovis must be confirmed by laboratory methods. This study aimed at comparing the performances of the standard diagnostic tools used to identify M. bovis in tissue specimens sampled from suspicious animals. During a two years period, 1390 cattle were inspected at the Machachi abattoir in the Mejia canton - Ecuador. A total of 33 animals with granulomatous lesions were detected, representing 2.33% (16/687) and 2.42% (17/703) animals examined in 2007 and 2008, respectively. Ninety-four tissue specimens were sampled and screened for the presence of mycobacteria. Acid-fast bacilli were identified in one third of the suspicious cattle (11/33) and suggestive microscopic lesions in 27.3% (9/33) of the samples examined by direct microscopy and histopathology, respectively. Culturing on Stonebrink medium and 16S-rRNA-based polymerase chain reaction (PCR) yielded 36.4% (12/33) and 27.3% (9/33) of positives, respectively. Compared to culture, other diagnostic procedures displayed a lower sensitivity, with 56.5% for PCR, and 43.5% for direct microscopy and histopathology; however, the specificity was higher (94.4% for PCR and microscopy, and 97.2% for histopathology). We conclude that reliable post-mortem laboratory testing either requires the combination of a set of available diagnostic tools or necessitates the development of improved new-generation tools with better sensitivity and specificity characteristics. 相似文献
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Luca Pipino Marie-Christine Van Labeke Andrea Mansuino Valentina Scariot Annalisa Giovannini Leen Leus 《Euphytica》2011,178(2):203-214
Fertility of hybrid tea roses is often reduced due to their interspecific origin but also to intensive inbreeding. New genotypes
used as pollen donors represent an economic risk for a breeding programme, as their influence on seed production is unknown.
In this study 11 cut rose genotypes were selected from a company database as high fertile or low fertile male parents, according
to the number of seeds per hybridisation. Pollen morphology and in vitro germination of the selected genotypes were characterised.
Pollen was either small (mean diameter <30 μm), shrunken, and irregular (abnormal), or large (mean diameter >30 μm), elliptical
and crossed by furrows (normal). High correlations were found between the number of seeds produced per hybridisation and the
pollen diameter (r = 0.94) or the percentage of normal pollen (r = 0.96). In order to evaluate the predictive power of the models, we conducted regression analyses and performed a validation
experiment on genotypes not present in the database and without background information on fertility. Pollen diameter and percentage
of normal pollen were characterised and fitted in the regression models for seed set predictions. Validation with an independent
dataset gave a good prediction for 83.3% of the data. This indicates that using either the mean pollen diameter or the percentage
of normal pollen resulted in effective fertility prediction. This tool could enhance the genetic variability in crossings
between hybrid tea roses, thus creating possibilities for less economically risky exploitation of new tetraploid genotypes
as male parents. 相似文献
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Hossein Hosseini Moghaddam Leen Leus Jan De Riek Johan Van Huylenbroeck Erik Van Bockstaele 《Euphytica》2012,184(3):413-427
Disease resistance is a sought-after trait in plant breeding programmes. One strategy to make resistance more durable is to
increase the number of resistance genes, thereby increasing the number of pathotypes withstood. One of the most important
diseases on roses is powdery mildew (PM) (Podosphaera pannosa). Recent studies show that pathotypes of PM and different types of resistances in roses exist. The results of this study
aim to contribute to PM resistance in roses by the development of pathotype-specific markers on a genetic map. A diploid rose
population (90 genotypes) derived from a cross between Rosa wichurana and Rosa ‘Yesterday’ was used to construct a genetic linkage map encompassing 20 AFLP primer combinations, 43 SSR, and 2 morphological
markers. By applying the F1 pseudo test cross population strategy, two parental linkage maps were constructed (parent ‘Yesterday’
536 cM; parent R. wichurana 526 cM). Both parental maps consisted of seven linkage groups with an average length of 70 cM (Kosambi) corresponding to
the seven haploid rose chromosomes. These new maps were used to identify QTLs controlling disease resistance. The offspring
population was screened for resistance to two PM pathotypes, R–E and R–P. QTLs for controlling pathotype-specific disease
resistance were mapped by applying Kruskal–Wallis rank-sum tests and simple interval mapping. With two pathotypes analysed,
nine QTL loci were detected on linkage groups 2, 3, 5 and 6, explaining 15–73% of the phenotypic variance for pathotype-specific
disease response. The genetic maps developed here will be useful for future rose breeding, pathotype-specific resistance research
and development of a consensus map for roses. 相似文献