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排序方式: 共有321条查询结果,搜索用时 15 毫秒
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胡勇 《青海畜牧兽医杂志》2011,41(1):10-11
以新鲜牦牛乳为原料,研究了Scamorza奶酪的制作技术,采用四因素三水平正交试验的方法,研究了不同量的凝乳酶、氯化钙、食盐以及发酵温度对成品的口感、色泽质地的影响,最终确定了该产品生产的最佳配方及技术条件:凝乳酶0.003%、氯化钙0.01%、食盐22%,发酵温度为32℃. 相似文献
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Three of the most commonly used veterinary antibiotics—enrofloxacin (ENR), sulfamethoxazole (SMX), and oxytetracycline (OTC)—were chosen as representative antibiotics for UV/H2O2 treatments. The objective was to determine the optimization of UV/H2O2 to remove antibiotics from aquaculture discharge water using response surface methodology. The degradation of the antibiotics was investigated under varying UV/H2O2 conditions in environments with different levels of pH, water matrices, humic acid, and constituent ions. The degradation results demonstrated that increasing the H2O2 dosage facilitated ENR degradation at a neutral pH while facilitating degradation of SMX and OTC at a slightly acidic pH. The optimum removal conditions for ENR, which was used in all influential effect experiments and the contact tank experiments, was obtained at 10 mM H2O2, a pretreated COD of 87.51 mg L−1, and an initial pH of 6.15. Among the tested anions, only the presence of Cl- showed slight positive effects on ENR degradation, due to the generation of secondary active radicals. During the reaction, the hydroxyl radical (OH) was present at a higher pH while singlet oxygen (1O2) was slightly present at a lower pH. The experimental results from H2O2 sequential addition indicated that freshly added H2O2 could quench the recently generated OH and therefore a high H2O2 concentration with frequent adding was not necessary. Our contact system reduced the ENR concentration in both the effluent reservoir and in the UV irradiation zone. The overall results supported the use of the UV/H2O2 system to treat remnant antibiotics in the discharge water. 相似文献
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This experiment aimed to examine the effect of periodical application of bioactive peptides derived from cottonseed (BPC) in comparison with using sub-therapeutic doses of lincomycin and the excessive inclusion of vitamin E on performance, immunity, total antioxidant capacity of serum and intestinal morphology of broiler chickens. A total of 240 one-d-old male broiler chicks with similar initial weight (Ross strain) were randomly assigned to 6 groups (8 chicks/pen): non-treated group (basal diet), basal diet supplemented with 2 mg/kg lincomycin, basal diet supplemented with 50 IU vitamin E, basal diet supplemented with 6 g BPC/kg in starter period, basal diet supplemented with 6 g BPC/kg in starter and grower periods and basal diet supplemented with 6 g BPC/kg throughout the whole experiment. The highest final body weight was obtained in the group supplemented with BPC in starter and grower periods. In the finisher phase, broilers fed the diet containing BPC in the starter period and in the whole trial had significantly (P < 0.05) better feed conversion ratios (FCR). Jejunal villus height was significantly elevated in broilers supplemented with antibiotic (P < 0.001), furthermore it tended to be greater in broilers fed BPC in the starter period. The jejunal villus height-to-crypt depth ratio was significantly (P < 0.01) higher in broilers fed the diet containing antibiotic in comparison to other groups. Humoral immune response against Newcastle disease vaccine tended to be elevated in broilers fed the diet containing BPC in the whole trial (P > 0.05). Broilers supplemented with BPC in starter and grower, and in the whole trial had significantly (P < 0.05) higher antibody titers against sheep red blood cells (SRBC). The highest total antioxidant capacity was obtained in broilers supplemented with the excessive level of vitamin E, furthermore it tended to improve in broilers fed the diet containing BPC in the whole trial. In summary, the results of the study indicated that addition of BPC in broiler diets in the whole trial could improve FCR, immune responses and total antioxidant activity of serum, and BPC could be used in broiler diets as an alternative to in-feed antibiotics. 相似文献
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Rémi Mongruel Olivier Thébaud 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3):163-181
ABSTRACT Most marine aquaculture activities remain strongly dependent on coastal ecosystems. In the case of shellfish farming, this dependency is related mainly to water quality and to the various ecological interactions resulting from the dynamics of coastal food webs. Such ecological constraints have influenced the overall evolution of blue mussel farming in the Mont-Saint-Michel Bay, leading producers to negotiate collective arrangements regarding production capacity and techniques and to develop production strategies at the farm level. This article presents an analysis of the location choices of mussel farmers in the Mont-Saint-Michel Bay based on an empirical investigation conducted in 2002. A typology of farms with respect to their land structure is developed in which some farms choose to concentrate their activity in a single part of the bay while others distribute their activity more widely. Determinants of the location choices of each farm category, including distance to port, natural productivity differentials, and predation of mussel stocks, are analyzed. The role of the institutional arrangements allowing mussel farmers to develop these location strategies is also discussed. 相似文献
6.
为了解对虾养殖池中副溶血弧菌(Vibrio parahaemolyticus)的耐药性和毒力基因的携带情况,2018年从山东4个地区的对虾养殖池收集分离副溶血弧菌,采用Kirby-Bauer纸片法检测其对12种抗生素的耐药性,用PCR方法检测其携带耐热直接溶血素基因(tdh)和耐热相关溶血素基因(trh)的情况。从对虾养殖池共分离副溶血弧菌50株。药敏实验结果显示,副溶血弧菌对庆大霉素、硫酸新霉素和氨苄西林的耐药情况最为严重,耐药率分别高达98%、90%和86%,对氟苯尼考、氯霉素、头孢他啶等敏感性较高,耐药率分别为10%、10%和20%。88%的菌株具有多重耐药性。毒力基因检测结果显示,所有菌株均不携带tdh基因,4%的菌株表现为trh阳性。本研究表明,对虾养殖水环境中的副溶血弧菌对抗生素的耐药性较为严重,应加强副溶血弧菌的病原学监测,在养殖过程中合理使用抗生素,以实现水产养殖业健康发展。 相似文献
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一株大豆内生拮抗细菌XZ-2的分离和分子鉴定 总被引:2,自引:0,他引:2
从大豆植株中分离到一株具有广谱抗菌活性的拮抗细菌,命名为XZ-2。抑菌活性测定显示XZ-2对甘薯黑斑病菌、大蒜叶枯病菌等8种植物病原真菌均具有较强的抑菌活性,抑菌直径均在20 mm以上。采用分光光度法绘制了XZ-2的生长曲线,结果显示该菌株在LB液体摇培12 h时基本达到对数生长期,该生长曲线的绘制为后期XZ-2的活性物质发酵条件优化奠定了基础。通过PCR扩增16Sr DNA片段并采用MEGA 6.0构建系统发育进化树,初步将该菌株鉴定为多粘类芽孢杆菌。 相似文献
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泰乐菌素和土霉素在农业土壤中的消解和运移 总被引:3,自引:0,他引:3
长期施用禽畜排泄物可导致抗生素在土壤中的积累, 对环境产生不良影响.为了解进入农田后抗生素的去向及残留动态, 选择2个典型农业土壤, 利用田间小区试验, 研究了田间实际状况下泰乐菌素和土霉素2种抗生素在土壤中的消解与运移行为.研究表明, 抗生素在土壤中的消解和运移与抗生素种类和土壤性质有关.抗生素在砂质土壤(清水砂)中的下移明显高于粘壤土(泥质田), 泰乐菌素在土壤中的垂直迁移强于土霉素.表层土壤中抗生素因降解和下移随时间逐渐下降, 消解速率在试验初期大于后期, 并且土霉素消解速率大于泰乐菌素.砂质土壤中抗生素的消解速率在试验初期明显高于粘壤土, 但至试验后期, 二者渐趋相似.田间条件下测得的抗生素消解速率明显低于实验室条件下, 这可能与抗生素进入田间深层土壤后稳定性增加有关.农田施用抗生素初期产生的径流中含较高浓度的抗生素, 但随时间(10 d之内)很快下降至检测下限以下; 试验初期径流中抗生素浓度为泰乐菌素大于土霉素, 砂质土高于粘壤土. 相似文献