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采用溶剂提取活性白土中的3种塑化剂(DBP、DEHP、DINP),提取液经SPE柱净化后,进气相色谱-质谱仪测定。以3种塑化剂的含量为考察指标,对活性白土中塑化剂含量测定的前处理条件进行了单因素实验和正交实验优化。结果表明,活性白土中塑化剂含量测定的最佳前处理条件为:甲醇饱和的正己烷溶液为提取溶剂,提取溶剂用量5 mL(活性白土1 g),提取时间3 min,提取温度20 ℃。在最佳前处理条件下,活性白土中3种塑化剂DEHP、DINP、DBP的含量分别为3.621、0004、0.078 mg/kg。 相似文献
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Yan Li Yizhao Shen Jiankang Niu Yanfei Guo Mirielle Pauline Xiaojing Zhao Qiufeng Li Yufeng Cao Chongliang Bi Xiujiang Zhang Zhonghua Wang Yanxia Gao Jianguo Li 《Journal of dairy science》2021,104(1):381-390
This study was conducted to examine the effect of active dry yeast (ADY) supplementation on lactation performance, ruminal fermentation patterns, and CH4 emissions and to determine an optimal ADY dose. Sixty Holstein dairy cows in early lactation (52 ± 1.2 DIM) were used in a randomized complete design. Cows were blocked by parity (2.1 ± 0.2), milk production (35 ± 4.6 kg/d), and body weight (642 ± 53 kg) and assigned to 1 of 4 treatments. Cows were fed ADY at doses of 0, 10, 20, or 30 g/d per head for 91 d, with 84 d for adaptation and 7 d for sampling. Although dry matter intake was not affected by ADY supplementation, the yield of actual milk, 4% fat-corrected milk, milk fat yield, and feed efficiency increased quadratically with increasing ADY supplementation. Yields of milk protein and lactose increased linearly with increasing ADY doses, whereas milk urea nitrogen concentration and somatic cell count decreased quadratically. Ruminal pH and ammonia concentration were not affected by ADY supplementation, whereas ruminal concentration of total volatile fatty acid increased quadratically. Digestibility of dry matter, organic matter, neutral detergent fiber, acid detergent fiber, nonfiber carbohydrate, and crude protein increased quadratically with increasing ADY supplementation. Supplementation of ADY did not affect blood concentration of total protein, triglyceride, aspartate aminotransferase, and alanine aminotransferase, whereas blood urea nitrogen, cholesterol, and nonesterified fatty acid concentrations decreased quadratically with increasing ADY supplementation. Methane production was not affected by ADY supplementation when expressed as grams per day or per kilogram of actual milk yield, dry matter intake, digested organic matter, and digested nonfiber carbohydrate, whereas a trend of linear and quadratic decrease of CH4 production was observed when expressed as grams per kilogram of fat-corrected milk and digested neutral detergent fiber. In conclusion, feeding ADY to early-lactating cows improved lactation performance by increasing nutrient digestibility. The optimal ADY dose should be 20 g/d per head. 相似文献
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将蒜黄根中提取的总膳食纤维(total dietary ifber,TDF)添加于低脂乳化肠,探究蒜黄根TDF对低脂乳化肠品质的影响.以正常脂肪添加量为对照组,实验组减少15%(以降低脂肪含量前瘦肉与猪背膘的总质量为基准)脂肪后分别添加不同质量的蒜黄根TDF(1.25%、2.50%、3.75%、5.00%、6.25%,... 相似文献
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