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排序方式： 共有37条查询结果，搜索用时 31 毫秒
21.
The current study aimed to determine the effects of dietary probiotic supplementation on growth, gut morphology and non‐specific immune parameters in Senegalese sole (Solea senegalensis) juveniles during a 1‐month trial. Fish were fed for 1‐month two diets with 1.0 or 4.6 × 106 CFU kg?1) of probiotic A (Bacillus sp., Pediococcus sp., Enterococcus sp. and Lactobacillus sp.) and two diets with 3.5 or 8.6 × 105 CFU kg?1 of probiotic B (Pediococcus acidilactici) and tested against an unsupplemented diet (control). Growth performance, as well as respiratory burst activity, nitric oxide (NO), alternative complement pathway (ACH50), lysozyme and peroxidase activities, was not affected by the dietary treatments. Probiotic supplementation tended to increased growth homogeneity between tanks having diet A1 the best possible alternative to decrease costs associated to size grading. Villous length and number of goblet cells of the anterior intestine did not vary among treatments. Muscle duodenal layer was significantly thicker in fish fed probiotic A compared to probiotic B, when included at the lowest level (A2 versus B2). The current study indicate that the use of the multispecies probiotic at 1.0 × 106 CFU kg?1 might enhance protection against pathogen outbreak and increase nutrient absorption, whereas at the highest concentration could reduced size dispersion among tanks.  相似文献   
22.
A 17‐week feeding trial was carried out to evaluate the effects of dietary L‐carnitine level in beluga, Huso huso. A total of fish averaging 1247 ± 15.6 g (mean ± SD) were randomly distributed into 18 fibreglass tanks, and each tank holding 10 fish was then randomly assigned to one of three replicates of six diets with 50, 150, 350, 650, 950 and 1250 mg L‐carnitine kg?1 diet. At the end of 17 weeks of feeding trial, average weight gain (WG), feed efficiency (FE), protein efficiency ratio (PER) and condition factor (CF) of fish fed 350 mg kg?1 diet were significantly (P < 0.05) higher than those of fish fed 50, 150, 950 and 1250 mg kg?1 diets. WG, FE, PER and CF of beluga fed 650 mg kg?1 diet were also significantly higher than those of fish fed 50, 950 and 1250 mg kg?1 diets. Whole body and muscle protein were significantly improved by the elevation of dietary L‐carnitine level up to 350 mg kg?1. Liver superoxide dismutase and glutathione peroxidase activities of fish fed 350 and 650 mg kg?1 diets were significantly higher than those of fish fed 50, 950 and 1250 mg kg?1 diets. The dietary L‐carnitine level of 350–650 mg kg?1 diet could improve growth performance, feed utilization, protein‐sparing effects of lipid, antioxidant defence system and reproductive success. Polynomial regression of WG suggested that the optimum dietary L‐carnitine level was 480 mg kg?1 diet. Therefore, these results may indicate that the optimum dietary L‐carnitine could be higher than 350 but <650 mg kg?1 diet in beluga reared in intensive culture conditions.  相似文献   
23.

The current study evaluated the effects of dietary seaweed supplementation in European seabass juveniles (Dicentrarchus labrax) subjected to rearing temperature and salinity oscillations, simulating natural variations in pond aquaculture conditions. Two experimental diets where formulated: a control diet (CTRL) with no supplementation and one supplemented with 7.5% seaweed mix (SW 2.5% Fucus sp., 2.5% Gracilaria sp. and 2.5% Ulva sp.). Seabass from both dietary groups (40.7 g initial body weight) was subjected to either combined salinity and temperature oscillations, or to fixed conditions. Growth performance, innate immune, and oxidative stress responses were evaluated. Results showed that seaweed supplementation had no significant effect on the analyzed parameters. However, environmental oscillations revealed significant effects on growth performance and oxidative stress response. Fish subjected to salinity and temperature oscillations had a significantly lower weight gain and daily growth index than those subjected to fixed conditions, regardless of dietary treatment. Total glutathione, oxidized glutathione, and catalase increased in fish subjected to oscillatory conditions. Lysozyme and peroxidase were not influenced by either diet or environmental conditions. In conclusion, this particular dietary seaweed mix supplementation did not mitigate the negative effects of environmental oscillations on growth performance and innate immune responses in European seabass.

  相似文献   
24.
Probiotic administration is associated with the enhancement of host resistance to environmental and nutritional stressors, improving survival and growth rates. This study was carried out to evaluate the effects of dietary supplementation of Bacillus subtilis and Bacillus cereus toyoi on growth performance, innate immune responses and gut morphology of two trout species feeding a commercial diet high in soybean meal. A commercial probiotic (4.2 × 109 CFU g?1 of additive) was supplemented to the experimental diets at 0% (control), 0.03% (P1; 6 × 103 CFU g?1 of diet) or 0.06% (P2; 1.5 × 106 CFU g?1 of diet) and fed to brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) for 9 and 20 weeks respectively. Rainbow trout showed significantly better growth performance than brown trout, regardless of the dietary treatment. No effect of dietary probiotic supplementation was detected on growth performance, body composition or innate immune parameters (plasma lysozyme, alternative complement and peroxidase activities). In both species, after 9 weeks, intestinal lamina propria and submucosa were widened, with increased presence of inflammatory cells, significantly higher in groups fed probiotics. This inflammatory process, with villi and enterocytes noticeably damaged compared with the control group, was more pronounced in brown trout. Under the current trial conditions, the B. subtilis + B. cereus toyoi had no positive impact in either trout species, on the contrary a harmful effect was observed.  相似文献   
25.
The present study investigated the qualitative amino acid (AA) requirements of larval African catfish Clarias gariepinus. Yolk-sac larval AA profiles were measured at different temperatures and also in animals reared at 28 °C fed Artemia nauplii or an experimental dry diet. The AA profile of C. gariepinus larvae changed during ontogeny, especially before the start of exogenous feeding. The AA profiles of the food items (yolk, Artemia and the dry diet) differed considerably from that of the larvae. No selective absorption of yolk AA was detected. Higher temperatures led to increased absorption and depletion rates of AA, and also to a higher retention efficiency of yolk nutrients. However, changes in temperature did not induce preferential absorption or depletion of individual AA, and caused only small variations in the AA profile. Depletion rates of individual AAs varied, possibly due to differences between larval and yolk AA profiles, and also to changes in the larval AA profile during ontogeny. There was little regulation of catabolism of individual AA in yolk-sac and starved larvae, and no sparing of essential AA.  相似文献   
26.
Livestock producers are interested in growing forage soybean [Glycine max (L.) Merr.] in summer and ensiling alone or in mixtures with corn or sorghum. Four row spacings (20, 40, 60, and 80 cm), four seeding rates (50, 100, 150, and 200 kg seeds per hectare) and four harvesting stages for forage production (V5, R2, R4, and R6) were evaluated under irrigated conditions in a randomized split–split plot design with three replications in three different locations in Turkey with Mediterranean-type climate in 2004 and 2005. Dry matter (DM) yield was significantly reduced with increased row spacings in all locations. There was no significant difference between 20, 40, or 60 cm row spacings while 80 cm provided the lowest yield. Increased seeding rates (50, 100, 150, and 200 kg seeds per hectare) generally increased DM yield, although the most suitable row spacing varied by location. DM yield was significantly affected by harvest maturity increasing with advancing maturity in all locations. DM constituent plant components were generally unaffected by row spacing and seeding rate but harvest maturity did significantly affect DM partitioning. As expected, leaf blade fractions decreased continually as plant maturity increased, while stem and flower plus pod fraction increased from V5 to R6. In general, row spacing and seeding rate did not significantly affect crude protein, degradable protein, and in vitro dry matter digestibility of soybean forage, but all decreased significantly with advancing maturity. These studies demonstrated soybeans managed for forage in a Mediterranean-type environment can average of 9.3 and 11.3 t ha−1 dry matter yield at R4 and R6 stages, respectively, while averaging 13.3% crude protein, 8.2% degradable protein, and 60.6% in vitro dry matter digestibility.  相似文献   
27.
Background  Increasing awareness in the last decade concerning environmental quality had prompted research into ‘green solutions’ for soil and water remediation, progressing from laboratoryin vitro experiments to pot and field trials. In vitro cell culture experiments provide a convenient system to study basic biological processes, by which biochemical pathways, enzymatic activity and metabolites can be specifically studied. However, it is difficult to relate cell cultures, calli or even hydroponic experiments to the whole plant response to pollutant stress. In the field, plants are exposed to additional a-biotic and biotic factors, which complicate further plant response. Hence, we often see thatin vitro selected species perform poorly under soil and field conditions. Soil physical and chemical properties, plantmycorrhizal association and soil-microbial activity affect the process of contaminant degradation by plants and/or microorganisms, pointing to the importance of pot and field experiments. Objective  This paper is a joint effort of a group of scientists in COST action 837. It represents experimental work and an overview on plant response to environmental stress fromin vitro tissue culture to whole plant experiments in soil. Results  Results obtained fromin vitro plant tissue cultures and whole plant hydroponic experiments indicate the phytoremediation potential of different plant species and the biochemical mechanisms involved in plant tolerance. In pot experiments, several selected desert plant species, which accumulated heavy metal in hydroponic systems, succeeded in accumulating the heavy metal in soil conditions as well. Conclusions and Recommendations   In vitro plant tissue cultures provide a useful experimental system for the study of the mechanisms involved in the detoxification of organic and heavy metal pollutants. However, whole plant experimental systems, as well as hydroponics followed by pot and field trials, are essential when determining plant potential to remediate polluted sites. Multidisciplinary research teams can therefore increase our knowledge and promote a practical application of phytoremediation.  相似文献   
28.
Young Holstein-Friesian bull calves were used in a controlled experiment to evaluate the efficacy of monensin against coccidiosis. The calves were given oocysts of Eimeria bovis and/or E. zurnii. Medication was started 3 days prior to inoculation and continued during the 30-day experimental period. Oocyst shedding was quantified prior to and throughout the experiment and demonstrated that monensin at the rate of 20 or 30 g ton-1 of feed significantly reduced oocyst shedding and clinical coccidiosis. Clinical infection with E. zurnii was very difficult to establish, even when calves were treated with 20 mg dexamethasone IM on Days 12, 15, and 16 post-inoculation.  相似文献   
29.
This report describes two cases of oesophageal tumours managed by transendoscopic neodymium:yttrium‐aluminum‐garnet laser ablation and polypectomy snare electrocautery. In each dog oesophagoscopy revealed caudal oesophageal masses, suspected to be Spirocerca lupi‐induced oesophageal neoplasia. To resect the masses, transendoscopic neodymium:yttrium‐aluminum‐garnet laser ablation was used in the first case and polypectomy snare electrocautery in the second. Recovery was uneventful. Histopathology was consistent with oesophageal fibrosarcoma and osteosarcoma in each case, respectively. Follow‐up oesophagoscopy revealed apparently healthy oesophageal tissue except for focal scar tissue in the first case. Transendoscopic laser ablation and polypectomy snare electrocautery is a potential non‐invasive, cost effective alternative for surgical oesophageal mass resection.  相似文献   
30.
A priority list of 323 plant species was created through a consultative process for ex situ conservation in the recently inaugurated Israel Plant Gene Bank (IGB). The IGB is set up to preserve plant genetic resources and the endangered genetic variability of the Israeli flora. Upon its inauguration, we consulted with the country’s leading plant breeders and botanists in an attempt to create a list of the most important plant species to be included in the initial collections. The list includes crop wild relatives (CWRs), selected according to their contribution to humans: edible plants (grains, vegetables, oil); forage plants; species with potential industrial and biotechnological applications (e.g. spices, medicinal plants, aromatic plants, fibers, dyes), and species with horticultural and forestry potential. We further ranked the species on the basis of assessed values for each of seven characteristics: distribution range in the country; abundance; rarity of the growing habitats; endemism; red number index—representing imminent threat of extinction; availability of samples in Israeli collections, and genetic relationship to cultivated crops. The sum of the assessed values for these seven characteristics was used to group the species on the list into four main prioritized-collection schemes. Statistical analysis indicated that all attributes had similar influence on the collecting prioritization scheme. In general, rare species with low abundance in their growing habitats were ranked in the highest priority group, while highly distributed species were sorted together into a lower priority group. The prioritization scheme will be used to optimize the collection in the IGB with the aim of establishing its collecting activities.  相似文献   
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