The influence of charcoal and smoke condensates (pyroligneous acid, PA) on microbial activity in a highly weathered Amazonian upland soil was assessed via measurements of basal respiration (BR), substrate-induced respiration (SIR), and exponential population increase after substrate addition. PA extracts are commonly used for fertilizer or as pest control in Brazil, where phosphorus (P) availability and nitrogen (N) leaching are among the most severe limitations for agriculture. Microbes play an important role in nutrient cycling and solubilizing of phosphate. BR, microbial biomass, population growth and the microbe's efficiency (expressed by the metabolic quotient) increased linearly and significantly with increasing charcoal concentrations (50, 100 and 150 g kg−1 soil). Application of PA caused a sharp increase in all parameters. We suppose that the condensates from smoke contain easily degradable substances and only small amounts of inhibitory agents, which could be utilized by the microbes for their metabolism. 相似文献
This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous‐induced Santa Inês ewes (6‐day treatment with progestin‐releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6–7 days after oestrous onset and mating. All ewes received 37.5 μg of d‐cloprostenol via latero‐vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non‐surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17–40 min) and ~96% of flushing fluid could be recovered (range: 85%–100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep. 相似文献
1. An experiment was conducted to compare the relative bioefficacy of DL‐methionine hydroxy analogue free acid (DL‐MHA‐FA) with DL‐methionine in broiler chickens. Responses used for comparison were weight gain and food efficiency between 7 and 35 d of age, and breast meat deposition, food cost per kg of breast meat, and abdominal fat at 41 d of age.
2. A total of 2160 seven‐day‐old male broiler chicks were used. The feeding programme consisted of a starter diet from 7 to 21 d, and a finisher diet till the end of the experiment. The starter basal diet contained 6.1 g/kg total sulphur‐containing amino acids (TSAA), and an estimated metabolisable energy (ME) content of 13.2 MJ/kg. The finisher diet contained 5.8 g/kg TSAA and an estimated ME content of 13.6 MJ/kg. Four concentrations of DL‐methionine and DL‐MHA‐FA were added at 0.5g/kg increments on an equimolar basis. Therefore, there were 9 experimental treatments which were each applied to 6 replicates of 40 chicks. Weight gain and food efficiency were determined at 35 d of age. Breast yield and carcase fat were measured at 41 d.
3. Significant responses to graded amounts of both methionine sources were observed in weight gain, food efficiency, breast meat percentage, and food cost per kg of breast meat. The responses fitted exponential regression curves. Based on the regression coefficients, equimolar bioefficacy of DL‐MHA‐FA relative to DL‐methionine was 80% for daily gain, 83% for food efficiency, 51% for breast meat yield, and 66% for food cost per kg of breast meat. Differences between the 2 sources were significant (P< 0.05) for breast meat yield and food cost per kg of meat and (P< 0.10) for food efficiency. 相似文献
1. The effect of three metabolisable energy (ME) concentrations 12.2, 11.3 and 10.5 MJ ME/kg and two forms of diet (mash and pellet) on egg production in summer and winter were studied. The different ME values were obtained by diluting the 12.2 MJ ME/kg diet with sugar beet pulp of 2.88 MJ/kg DM. In a 3rd summer experiment the water intake of hens on these diets was examined. Data were analysed by factorial analysis of variance, and the relationship between performance and dietary energy concentration was examined by regression analysis.
2. The use of low energy diets (10.5 to 11.3 MJ ME/kg) decreased egg production in both seasons, but pelleting diets improved egg production and egg weight in summer. Egg weight was not affected by energy density in winter, but decreased in the summer when energy density increased.
3. In winter, food consumption was not affected by the dietary ME, while in summer food consumption increased when the dietary ME increased. Therefore, energy intake was not the same at all energy densities, but tended to increase as the energy density increased.
4. In summer, pelleting improved food efficiency and egg production and increased water consumption and the ratio of water to food intake. Water intake and water: food ratio decreased with increasing dietary energy concentration. 相似文献
This article is aimed to persuade most bovine practitioners that FET is a therapeutic tool that can easily be used under field conditions, and that by following the right protocol, one can provide a cost-effective treatment for the farmer, a rewarding experience for us, and a boost for our professional image. Based on the excellent current publications, the scheme of work to put FET into practice is presented. Controversial decisions must be made (such as oral vs. parenteral fluids, removing milk from diet vs. continued feeding, oral fluids with bicarbonate vs. those with metabolizable bases, and so forth). Practicality, economy, and owner compliance are critical components of a successful protocol. This work protocol is based on the current literature, considers controversial subjects, such as route of administration, alkalinizing agents, and fasting, employs simple yet effective techniques, and is successful in a high percentage of cases. 相似文献
Cylindrospermopsin (CYN) is a cyanotoxin that is cytotoxic to a wide variety of cells, particularly to the hepatocytes. In this study, the toxic effects of purified CYN were investigated in primary cultured hepatocytes of Neotropical fish Hoplias malabaricus. After isolation, attachment, and recovery for 72 h, the cells were exposed for 72 h to 0, 0.1, 1.0, 10, and 100 μg l?1 of CYN. Then, cell viability and a set of oxidative stress biomarker responses were determined. Catalase, superoxide dismutase, glucose-6-phosphate dehydrogenase, and glutathione S-transferase activities were not affected by exposure to CYN. Concentration-dependent decrease of glutathione reductase activity occurred for most CYN-exposed groups, whereas non-protein thiol content increased only for the highest CYN concentration. Lipid peroxidation, protein carbonylation, and DNA damage levels were not altered, but reactive oxygen species levels increased in the cells exposed to the highest concentration of CYN. Cell viability decreased in all the groups exposed to CYN. Thus, CYN may cause a slight change in redox balance, but it is not the main cause of cell death in H. malabaricus hepatocytes. 相似文献