如何应用GB13086-91法准确测定饲料中游离棉酚的含量

本文旨在探讨如何应用GB13086-91法准确测定棉粕和含有棉粕的饲料产品中游离棉酚的含量.实验表明,正确掌控测定过程中试剂的处理、称样、显色等几个关键环节,尤其注意空白试验的蒸馏和试液的加热方法,有助于提高游离棉酚测定结果的准确性和安全性.     

高效液相色谱法测定高压灭菌及低温烘干对棉粕中棉酚含量的影响

棉粕富含丰富的蛋白质．但因其含有抗营养因子游离棉酚而使其使用量受到极大的限制。本研究采用HPLC法检测高压灭菌及烘干对棉粕中游离棉酚含量的影响。将棉粕按料水比1：1．2混匀．121℃高压灭菌30min．然后45℃烘干24h．检测其游离棉酚的含量变化。结果表明：棉粕原料中游离棉酚检测含量为1300．31μg/g;经高温灭菌后,其含量为77．29μg/g,降解率达94％;对灭菌样品进行烘干后。游离棉酚含量达到极低,未检测到峰．其降解率大于98％,但高温后生成何物质有待进一步研究。     

棉籽饼粕饲料中游离棉酚含量测定方法的改进

为探讨适用基层单位大批量棉籽饼粕饲料中游离棉酚的测定方法,采用有机溶剂对棉籽饼粕饲料进行自然浸提(4,6,8,10,12,14,16 h),改进了游离棉酚含量的测定方法,并与国标法进行了比较。结果:随着浸提时间的延长,游离棉酚的含量逐渐增加,当浸提12 h后,游离棉酚的含量不再随着浸提时间的延长而增加;自然浸提12、14、16 h时游离棉酚的含量与国标法的测定结果无显著差异(P>0.05),相对偏差均小于5%;自然浸提12 h时游离棉酚的回收率也与国标法差异不显著(P>0.05)。表明此法操作简便,结果准确、可靠,可应用于基层单位大批量样品的检测。     

饲料中游离棉酚快速测定适宜条件的筛选

通过间苯三酚比色法和高效液相色谱法测定棉籽粕中游离棉酚含量,比较分析棉酚不同提取方法和不同样品称量的测定结果及回收率。结果表明:采用超声波滤取,间苯三酚比色法测定游离棉酚,操作简便、条件要求低、回收率较高。     

优化高效液相色谱法测定棉籽粕中游离棉酚的含量

本试验旨在建立一种测定棉籽粕中游离棉酚含量的高效液相色谱(hPLC)法的优化方法.试验采用丙酮提取棉籽粕样品,经超声、离心、抽滤、旋转蒸发处理,用乙腈-0.2％磷酸(体积比为85∶15)溶液溶解;色谱条件为:色谱柱Agilent TC-C18(250mm×4.6mm,5μm),流动相为乙腈-0.2％磷酸(体积比为85∶15)溶液,流速1.0mL/min,紫外检测波长235nm,进样量20μL,柱温25℃.结果得出,游离棉酚的回归标准曲线为y=189347x+24969(r=0.99999),在游离棉酚含量为0.1224～78.336 μg/mL范围内线性良好,最低定量限为0.52mg/kg;棉籽粕样品36h内4℃稳定性的相对标准偏差在1.51％～3.43％;平均回收率在94.72％～99.49％,相对标准偏差在1.72％～3.13％.可知,本方法稳定性好,准确度、灵敏度和回收率高.     

棉酚快速测定适宜条件的筛选

采用间苯三酚法和高效液相色谱法测定棉籽粕中游离棉酚含量,通过对提取方法和样品称量等测定条件筛选,并分析比较测定结果及回收率。结果表明:采用超声波滤取,间苯三酚法测定游离棉酚,具有操作简便、条件要求低、回收率高等优点,可作为企业内控质量检测推广应用方法。     

猪棉酚中毒的诊断和预防措施

棉粕中的有毒成分有游离棉酚、．棉酚紫和棉绿素3种色素,其毒性以棉绿素最强,游离棉酚次之。但游离棉酚的含量远比另外2种色素高,因此棉粕的毒性主要取决于游离棉酚的含量．棉粕中棉酚的含量通常为0．15％～0．18％。新疆是棉花主产区,棉粕产量很大,各猪场时常发生棉酚中毒事件．现就棉酚的毒性、危害和防治方法介绍如下。     

高效液相色谱测定棉酚方法的建立及不同棉酚脱毒方法比较

棉籽粕是一种非常有价值的蛋白质饲料,棉籽粕的有效脱毒可以提高饲料利用率。本试验建立了一种快速、准确测定棉籽粕游离棉酚的HPLC方法,并采用不同的脱毒方式对棉籽粕中的游离棉酚进行降解,筛选最优脱毒方法。结果显示:(1)HPLC法测定棉籽粕中棉酚含量,棉酚色谱峰出峰稳定性良好、分离效果好、峰型理想、灵敏度高,可以高效的检测棉酚含量;(2)不同处理方法对棉籽粕脱毒效果不同,棉酚脱毒率大小排序为:微生物法>硫酸亚铁法>尿素法>高温高压法。最优的方法为微生物法,酵母菌发酵48 h后的发酵棉籽粕棉酚降解率高达93.86%;化学法(硫酸亚铁法和尿素法)脱毒率为53.64%～78.18%,物理法(高温高压)脱毒率最低,为41.00%。     

浅谈猪棉酚中毒的诊断与预防

棉粕中的有毒成分有游离棉酚、棉酚紫和棉绿素3种色素,其毒性以棉绿素最强,游离棉酚次之。但游离棉酚的含量远比另外2种色素高,因此棉粕的毒性主要取决于游离棉酚的含量,棉粕中棉酚的含量通常为0.15%～0.18%。现就棉酚的毒性、危害和防治方法介绍如下。     

棉籽饼粕饲料中游离棉酚测定方法的研究

本文对棉籽饼粕饲料进行自然浸提,建立了游离棉酚含量的测定方法,并与国标法进行了比较。结果表明:(1)随着浸提时间的延长,游离棉酚的含量逐渐增加,当浸提13h后,游离棉酚的含量不再随着浸提时间的延长而增加;(2)并且自然浸提13、26、39h时游离棉酚的含量与国标法的测定结果无显著差异(P>0.05),相对偏差均小于5%;(3)同时自然浸提13h时游离棉酚的回收率也与国标法差异不显著(P>0.05)。证明此法操作简便,结果准确、可靠,可应用于基层单位大批量样品的检测。     

Near Infrared Reflectance Spectroscopy for the Determination of Free Gossypol in Cottonseed Meal

Gossypol is a toxic polyphenolic compound produced by the pigment glands of the cotton plant. The free gossypol content of cottonseed meal (CSM) is commonly determined by the American Oil Chemists’ Society (AOCS) wet chemistry method. The AOCS method, however, is laboratory-intensive, time-consuming, and therefore, not practical for quick field analyses. To determine if the free gossypol content of CSM could be predicted by near infrared reflectance spectroscopy (NIRS), CSM samples were collected from all over the world. All CSM samples were ground and a portion of each analyzed for free gossypol by the AOCS procedure (reference data) and by NIRS (reflectance data). Both reflectance and reference data were combined in a calibration. The coefficient of determination (r²) and standard error of prediction (SEP) were used to assess the calibration accuracy. The r² was 0.728, and the SEP was 0.034 for the initial calibration that included samples from all over the world. However, the r² and SEP improved to 0.921 and 0.014, respectively, if the calibration was made using CSM samples only from the United States. These results indicate that a general prediction equation can be developed to predict the free gossypol content of CSM by NIRS. From a practical standpoint, NIRS technology provides a method for quickly assessing whether a particular batch of CSM has a free gossypol content low enough to be suitable for use in poultry diets.     

棉籽饼粉脱毒饲料的制备及其应用效果初探

本试验通过制备棉籽饼粉脱毒饲料产品,采用感官鉴定法观察其物理性状,采用国标法测定其棉酚含量,采用凯氏定氮法测定其粗蛋白质含量,并通过肉鸭饲喂试验探讨其在肉鸭饲养过程中的应用效果.结果表明,脱毒后的棉籽饼粉中棉酚残存量不足10 mg/kg,与原始饼粕相比,粗蛋白质含量提高了4.35%,其颜色明显变浅,饼粕质地松软,硬度小,无硬块,无异臭,符合安全标准.经肉鸭饲喂试验发现,与对照组肉鸭相比,用制备的棉籽饼粉脱毒饲料代替常规饲料饲喂肉鸭其生长发育、器官发育、血液指标、饲料中营养成分利用情况均未发现异常,未发现棉酚中毒现象,说明脱毒后的棉籽饼粉饲料中棉酚含量符合饲用安全标准,达到脱毒目的.     

高效降解游离棉酚并改善棉籽粕营养品质的菌株筛选

本试验旨在利用枯草芽孢杆菌和植物乳酸菌发酵棉籽粕,研究其对棉籽粕中游离棉酚降解率的影响,并对发酵前后棉籽粕的营养品质指标如活菌数、中性蛋白酶活性、酸溶蛋白质含量、pH、游离棉酚含量等进行比较。结果发现:可高效降解棉籽粕中游离棉酚的枯草芽孢杆菌菌株为BLCC1-0039,可有效改善发酵风味的植物乳酸菌菌株为BLCC2-0092。综合上述2株益生菌的优点,筛选出最优复配发酵方式为植物乳酸菌BLCC2-0092与枯草芽孢杆菌BLCC1-0039按照1∶1比例接种,37℃需氧发酵24h再厌氧发酵。与空白对照组相比,最优复配发酵组各发酵阶段发酵棉籽粕的pH显著降低(P0.05),厌氧发酵72h时pH降至5.27;酸溶蛋白质含量显著提高(P0.05),厌氧发酵72h时酸溶蛋白质含量达到23.54%;游离棉酚含量显著降低(P0.05),需氧发酵24h时游离棉酚降解率达到52.12%,厌氧发酵72h时游离棉酚降解率达到61.58%。由此可知,植物乳酸菌BLCC2-0092与枯草芽孢杆菌BLCC1-0039复配发酵可有效降低发酵棉籽粕中的游离棉酚含量并改善其营养品质。     

两种不同发酵工艺的棉籽粕营养价值的研究

利用现代固态发酵原理,研究两种不同发酵工艺对棉粕脱毒效果及其营养价值的影响。工艺一是使用本实验室保存的两株菌直接进行固态发酵,工艺二是在工艺一的基础上添加酶解液进行固态发酵。试验结果表明(以干物质计),棉籽粕发酵和发酵酶解产品中游离棉酚分别降低到197.68 mg/kg和202.35 mg/kg,粗蛋白质分别提高到59.64%和60.88%,小肽含量分别提高到19.41%和23.59%。来航蛋公鸡强饲代谢试验结果表明,发酵和发酵酶解棉籽粕的能量和营养物质消化率均高于未发酵棉粕。肉鸡饲养试验结果表明,发酵棉粕按50%、75%和发酵酶解棉粕按75%的比例替代基础日粮中的豆粕,不影响肉鸡的日采食量。国标二级高游离棉酚棉籽粕经过固态发酵处理后,外观蓬松变软,气味芳香,其营养价值得到显著改善。蛋公鸡的营养物质及能量消化率得到显著提高,同时益生菌及生物酶活性增加,在肉仔鸡日粮中的应用不影响日采食量。     

固体联合发酵对棉粕发酵产物富肽蛋白产量及脱毒效果的影响

利用枯草芽孢菌（Bacillus subtilis NDX6）和植物乳杆菌（Lactobacillus plantarum BLLP）对棉粕、豆粕不同比例混合样品进行有氧和无氧联合发酵试验,并用纯棉粕进行联合发酵生长曲线研究,探讨固体联合发酵对棉粕发酵产物中富肽蛋白含量及脱毒效果的影响.结果表明,6个配方中纯棉粕发酵降解有毒物质游离棉酚含量最高约81％,游离氨基酸及小肽的含量提高约6.5倍（P＜0.05）,饲料pH由原来的6.20以上降低到5.12以下,有益菌活菌数提高约10倍;纯棉籽粕有氧发酵时间为38 h,无氧发酵时间60～66 h,游离氨基酸含量提高约7.54倍,游离棉酚降低约89％.用棉粕固体联合发酵可以脱毒,降解蛋白提高饲料吸收利用率.     

几种棉粕饲料的质量评定

试验旨在研究棉粕感官鉴定结果同其营养成分化学检验结果的相关性,为生产中感官检测提供理论依据。采集市面上不同产地及不同厂家的6种棉粕,测定其所含粗蛋白、游离棉酚、NDF、ADF、ADL的量。结果表明,6种棉粕所含游离棉酚量都在国标允许范围内,并且棉粕的色泽与游离棉酚含量有一定的相关性。试验数据表明,黄色棉粕较发红的棉粕游离棉酚含量高。棉壳含量是影响棉粕粗蛋白高低的主要因素,两者呈明显的负相关。棉壳和棉絮含量与纤维呈正相关,棉壳和棉絮含量过高则会影响到棉粕的品质。     

Pathological Lesions in Lambs Fed Raw or Processed Cottonseed Meal

Thirty male lambs of 3–4 months of age, were assigned equally to five dietary treatments in a completely randomized design and fed isonitrogenous and isocaloric concentrate mixtures containing 30% de-oiled peanut meal (DPNM) or 40% cottonseed meal, which was raw, cooked for 45 min or treated with either 1% calcium hydroxide or iron (1:3, free gossypol: Fe). The mixtures containing raw or variously processed CSM replaced about 50% of the nitrogen of the reference concentrate mixture. These concentrate mixtures were fed to meet 80% of the animals' crude protein requirements along with ad libitum feeding of maize (Zea mays) hay for 180 days. The free gossypol content of the raw cottonseed meal (0.27%) was reduced to 0.16%, 0.20% and 0.21% by the cooking, Ca(OH)₂ and iron treatments, respectively. At the end of the experiment, the tissues of various organs were fixed in 10% formol saline, embedded in paraffin and sectioned at 4–5 m thickness, and duplicate sections were stained with either haematoxylin and eosin or Perl's Prussian blue. The lambs fed diets incorporating raw, cooked, Ca(OH)₂- or iron-treated cottonseed meal consumed respectively 302, 215, 250 and 222 mg free gossypol/day. No morbidity, mortality or gross lesions were observed in any organs and the histopathological lesions due to cottonseed meal were limited to the testes and epididymis. Spermatogonial cells were absent in the majority of the seminiferous tubules of testes from lambs fed raw cottonseed meal. Most seminiferous tubules were collapsed, with a reduced wall thickness, owing to there being fewer germ cell layers and vacuolation of the basal cells. The epithelium of the epididymal ductules was degenerated, desquamated to a variable degree with hyperplastic changes, and they were devoid of spermatozoa. Most lambs fed any of the processed cottonseed meals did not show any of these lesions, and such lesions as occurred in affected lambs in these groups were relatively mild. Iron pigments were deposited around the portal areas of the liver, the tip of intestinal villi and the spleen of lambs fed the iron-treated cottonseed meal diet. Cooking or treatment with 1% Ca(OH)₂ effectively minimized the toxic effects of free gossypol.