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91.
Roberta Cavalcanti Nery Camila Barros Costa Flvio Rodrigues Roberta Soares Ranilson de Souza Bezerra Silvio Peixoto 《Aquaculture Nutrition》2019,25(3):577-584
The present study evaluated the effects of feeding frequency during the grow‐out phase of Litopenaeus vannameiin biofloc system. The experiment comprised of four treatments with three replicates each, corresponding to the following feeding frequencies: one (8:00 a.m.), two (8:00 a.m. and 4:00 p.m.), three (8:00 a.m., 12:00 p.m. and 4:00 p.m.) and four times a day (8:00 a.m., 10:00 a.m., 12:00 p.m. and 4:00 p.m.). Zootechnical performance and digestive enzyme activity were monitored for 63 days. At the end of the experiment, the highest survival rates were found for the individuals fed three and four times a day. Wet weight gain (6.63 g) and specific growth rate (3.46% per day) of the individuals fed three times a day were significantly higher compared to animals fed one and four times a day, but did not differ significantly to the group fed twice a day (6.15 g and 3.46% per day, respectively). The digestive enzyme activities were not affected by the feeding frequency, but negative correlations were found between these activities and shrimp weight. It is recommended that L. vannamei should be fed three times a day during the grow‐out phase in a biofloc system under the conditions used in this study. 相似文献
92.
Valdir M. Almeida Givaldo B. Silva-Filho Hisadora A. S. C. Bom Silvio M. C. Fonseca Franklin Riet-Correa Francisco A. Uzal Kevin D. Woolard Francisco A. L. Souza Fbio S. Mendona 《Journal of veterinary diagnostic investigation》2021,33(6):1128
An outbreak of acute encephalopathy occurred in pregnant ewes and their newborn lambs associated with consumption of Talisia esculenta fruits and bark. Clinical signs in 5 adult pregnant ewes included drooling, bloat, tachypnea, depression, ataxia, body shaking, difficulty in rising, and recumbency. Three neonatal lambs born to some of those ewes had similar clinical signs. No significant gross abnormalities were observed on autopsy. Histologically, neuronal necrosis, axonal and dendritic swelling, and loss of Purkinje neurons were observed in the cerebellum. The observation of similar neurologic clinical signs and lesions in pregnant ewes and their neonatal lambs suggests that the toxic principle of T. esculenta crosses the placenta and reaches the fetus. 相似文献
93.
94.
Emanuell Felipe Silva Marcelo Augusto Soares Nathalia Ferreira Calazans Joana Lyra Vogeley Bruna Cáritas do Valle Roberta Soares Silvio Peixoto 《Aquaculture Research》2012,44(1):13-21
The effect of the addition of Bacillus probiotic during larvae and postlarvae culture of the white shrimp Litopenaeus vannamei was examined in three separate experiments: (I) Nauplius4‐5 to Zoea3, which were exposed to probiotic in the water (Pw), only in the microalgae (Pm), in the water and microalgae (Pwm) and a control with no probiotic (C); (II) Mysis1 to Mysis3, which were exposed to probiotic in the water (Pw), only in Artemia (Pa), in the water and Artemia (Pwa) and a control (C); (III) PL1 to PL10, which were exposed to similar treatments for mysis experiment. The use of probiotic Bacillus spp. resulted in an increase in the survival and growth of zoea and mysis phases, especially when the probiotic was added only in the water. For postlarvae, the use of the probiotic had no influence on the zootechnical parameters, however, there was a reduction in the count of presumptive Vibrio both for water and shrimp. 相似文献
95.
96.
Adele Muscolo Maria Sidari Silvio Bagnato Carmelo Mallamaci Roberto Mercurio 《European Journal of Forest Research》2010,129(3):355-365
Changes in soil properties related to natural regeneration of silver fir (Abies alba, Mill.) in small (185 m2) and medium (410 m2) gaps, in the Calabria Apennines (Southern Italy), were studied 2 years after gap creation. The organic matter within the
medium gaps decayed more rapidly than those in the small gaps. Among the microenvironmental variables and soil properties,
soil temperature was most strongly positively related to organic matter decomposition rates. Medium gaps had high soil temperature
and photosynthetically active radiation (PAR) transmittance, and low soil moisture. Within medium gaps, we found a great amount
of phenolic compounds and a low content of organic matter and humic acids. These results indicate that in the medium gaps
mineralization of organic matter was more important than humification. In contrast, in small gaps, the great amount of organic
matter, the high content of humic acid and the values of humification index suggested that in these gaps the humification
process of organic matter prevailed. Within small gaps, we observed more silver fir regeneration than medium gaps. Difference
in organic matter content, particularly in the amount of phenolic compounds, may account for differences observed in natural
regeneration of silver fir between small and medium gaps. 相似文献
97.
The contribution of arbuscular mycorrhizal fungi in sustainable maintenance of plant health and soil fertility 总被引:22,自引:0,他引:22
Peter Jeffries Silvio Gianinazzi Silvia Perotto Katarzyna Turnau José-Miguel Barea 《Biology and Fertility of Soils》2003,37(1):1-16
Beneficial plant-microbe interactions in the rhizosphere are primary determinants of plant health and soil fertility. Arbuscular mycorrhizas are the most important microbial symbioses for the majority of plants and, under conditions of P-limitation, influence plant community development, nutrient uptake, water relations and above-ground productivity. They also act as bioprotectants against pathogens and toxic stresses. This review discusses the mechanism by which these benefits are conferred through abiotic and biotic interactions in the rhizosphere. Attention is paid to the conservation of biodiversity in arbuscular mycorrhizal fungi (AMF). Examples are provided in which the ecology of AMF has been taken into account and has had an impact in landscape regeneration, horticulture, alleviation of desertification and in the bioremediation of contaminated soils. It is vital that soil scientists and agriculturalists pay due attention to the management of AMF in any schemes to increase, restore or maintain soil fertility. 相似文献
98.
GI Dezmirean LA Mărghitaş O Bobiş DS Dezmirean V Bonta S Erler 《Journal of agricultural and food chemistry》2012,60(32):8028-8035
Honey as rich source of enzymatic and nonenzymatic antioxidants serves as health-promoting nutrient in the human body. Here, we present the first time a comparative study of nutritional profiles (e.g., acidities, sugar, organic acid profile, total polyphenolic, flavonoid content) for different unifloral, multifloral honeys and their fermented products, in correlation with their antioxidant activity. Additionally, an optimized method for HPLC separation of organic acids from honey was established. The total phenolic content of honey samples varied widely among the honey types compared to fermented products. High amounts of total flavonoids were quantified in heather honey, followed by raspberry, multifloral, black locust, and linden honey. A positive correlation between the content of polyphenols, flavonoids, and antioxidant activity was observed in honey samples. After fermentation, the flavonoid content of dark honey fermented products decreased significantly. Black locust and linden honeys are more suitable for fermentation because the decrease in antioxidant substances is less pronounced. 相似文献
99.
Vicente SJ Ishimoto EY Cruz RJ Pereira CD Torres EA 《Journal of agricultural and food chemistry》2011,59(20):10887-10892
This study evaluated the acute effect of the administration of coffee brew in the activity of phase II antioxidant enzymes in the hepatic tissue of rats. A single dose of this beverage increased the activity of the enzymes SOD, CAT, and GPx; the maximum increase occurred 1 h after administration (19.1, 22.1, and 25.1%, respectively). These changes were statistically significant (p < 0.05), the response was shown to be dose-dependent (p < 0.05), and the return to basal levels took >4 h from the intervention, suggesting a long-term effect. The total antioxidant capacity of the hepatic tissue also exhibited a peak 1 h after the intervention (6.5%), but the increase was not statistically significant and the response was not dose-dependent due to the low exposure to coffee. These results indicate that coffee increases the activities of antioxidant enzymes, improving protection against oxidative stress. 相似文献
100.
Silvio Frosini de Barros Ferraz Carlos Alberto Vettorazzi David M. Theobald 《Forest Ecology and Management》2009
In Rondônia State, Brazil, settlement processes have cleared 68,000 km2 of tropical forests since the 1970s. The intensity of deforestation has differed by region depending on driving factors like roads and economic activities. Different histories of land-use activities and rates of change have resulted in mosaics of forest patches embedded in an agricultural matrix. Yet, most assessments of deforestation and its effects on vegetation, soil and water typically focus on landscape patterns of current conditions, yet historical deforestation dynamics can influence current conditions strongly. Here, we develop and describe the use of four land-use dynamic indicators to capture historical land-use changes of catchments and to measure the rate of deforestation (annual deforestation rate), forest regeneration level (secondary forest mean proportion), time since disturbance (mean time since deforestation) and deforestation profile (deforestation profile curvature). We used the proposed indices to analyze a watershed located in central Rondônia. Landsat TM and ETM+ images were used to produce historical land-use maps of the last 18 years, each even year from 1984 to 2002 for 20 catchments. We found that the land-use dynamics indicators are able to distinguish catchments with different land-use change profiles. Four categories of historical land-use were identified: old and dominant pasture cover on small properties, recent deforestation and dominance of secondary growth, old extensive pastures and large forest remnants and, recent deforestation, pasture and large forest remnants. Knowing historical deforestation processes is important to develop appropriate conservation strategies and define priorities and actions for conserving forests currently under deforestation. 相似文献