幾種測量飼料蛋白質含量的對比分析
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蛋(dan)白(bai)質(zhi)營(ying)養(yang)是(shi)動(dong)物(wu)營(ying)養(yang)的(de)關(guan)鍵(jian),是(shi)動(dong)物(wu)生(sheng)長(chang)發(fa)育(yu)和(he)生(sheng)產(chan)的(de)基(ji)礎(chu),其(qi)含(han)量(liang)是(shi)評(ping)價(jia)飼(si)料(liao)營(ying)養(yang)品(pin)質(zhi)的(de)直(zhi)接(jie)指(zhi)標(biao)。測(ce)定(ding)飼(si)料(liao)粗(cu)蛋(dan)白(bai)質(zhi)含(han)量(liang)是(shi)否(fou)快(kuai)捷(jie),關(guan)鍵(jian)在(zai)於(yu)樣(yang)品(pin)消(xiao)化(hua)過(guo)程(cheng)是(shi)否(fou)方(fang)便(bian)、省時。目前GB/T6432-1994guidingleyongliusuantongzuocuihuajiyongnongliusuanjinxingxiaohua,xiaohuashijianjiaochang。benyanjiuyongnongliusuanheguoyanghuaqingjinxingyangpinxiaohua,bingjiangliangzhongxiaohuafangfadedaodexiaohuayejinxingceding,bijiaocededecudanbaizhihanliangdechayi。zhizaitantaoyizhongcudanbaicedingdekuaisuxiaohuafangfa,yibianmanzusiliaoqiyexuyaokuaisuhuodeyangpinjichanpinzhongcudanbaizhihanliangdeyaoqiu,zhenzhengdadaokuaisu、廉價、高效、節能。
開始研究之前準備好下麵的儀器和試劑:NPCa-02型氮、磷、鈣快速測定儀及四孔消化爐、實驗室用樣品粉碎機、分析天平、滴定管。試劑濃硫酸:(GB625)化學純;硫酸銅:(GB665)化學純;硫酸鈉:(HG3-920)化學純;鹽酸標準滴定液:0.05M鹽酸溶液;混合指示劑:甲基紅(分析純)1g•L-1乙醇溶液和溴甲酚綠(分析純)5g•L-1乙醇溶液等體積混合;硼酸吸收液:硼酸(化學純)10g•L-1溶液;40%氫氧化鈉溶液;30%過氧化氫。
采用的簡單消化方法:國標法、稱取樣品0.5-1g,準確至0.0002g,無損地放入消化管中,加入硫酸銅0.4g,硫酸鈉6g,與試樣混合均勻,再加入濃硫酸10mL和2粒玻璃珠。將消化管放入消化爐中小心加熱,待樣品焦化,泡沫消失,再加大火力使溫度達到360~410℃,直至溶液澄清後,再加熱消化15min。濃硫酸、過氧化氫法稱取樣品0.5-1g,準確至0.0002g,無損地放入消化管中,加入濃硫酸10mL,放入消化爐中,將消化爐電壓調至220V,消化至大量棕色煙冒出且消化液呈醬油色,取出消化管稍微冷卻後加入3~5mL過氧化氫,同時將消化爐電壓調至150~180V,並將消化管重新放入消化爐中消化2~35min,仍用上法,向消化管內滴入過氧化氫直至消化液幾乎無色,再移入消化爐中繼續消化5~10min取出,冷卻至室溫。氨的蒸餾:均采用半微量法進行蒸餾。
不同粗蛋白質含量的飼料產品的測定結果對魚配合飼料、豬濃縮料、乳豬配合飼料等6個樣品的粗蛋白質分別用兩種消化方法消化後進行測定,分別測定10次,測定結果見下表。

從表可見,對於不同飼料蛋白含量(CP18%~41%)的飼料產品而言,國標法所檢測到的粗蛋白質含量與濃硫酸、過guo氧yang化hua氫qing法fa測ce得de的de粗cu蛋dan白bai質zhi含han量liang相xiang比bi無wu顯xian著zhu差cha異yi。對dui於yu國guo標biao法fa中zhong樣yang品pin的de消xiao化hua所suo用yong試shi劑ji量liang較jiao小xiao,價jia格ge相xiang對dui偏pian低di,但dan存cun在zai消xiao化hua時shi間jian長chang,耗hao電dian多duo的de缺que點dian。一yi般ban樣yang品pin要yao達da到dao要yao求qiu需xu消xiao化hua1~2h。而利用濃硫酸、過氧化氫方法進行消化,每個樣品消化隻需30~40min即ji可ke。二er者zhe相xiang比bi每mei次ci消xiao化hua可ke以yi節jie約yue一yi半ban的de時shi間jian。從cong檢jian測ce結jie果guo看kan,兩liang種zhong消xiao化hua方fang法fa對dui粗cu蛋dan白bai質zhi的de測ce定ding結jie果guo無wu顯xian著zhu影ying響xiang。目mu前qian,飼si料liao中zhong粗cu蛋dan白bai測ce定ding的de國guo標biao法fa中zhong消xiao化hua使shi用yong濃nong硫liu酸suan,並bing用yong硫liu酸suan銅tong和he硫liu酸suan鈉na作zuo催cui化hua劑ji。在zai濃nong硫liu酸suan、過guo氧yang化hua氫qing法fa未wei列lie入ru國guo標biao之zhi前qian,飼si料liao企qi業ye對dui於yu常chang規gui質zhi檢jian可ke用yong此ci種zhong消xiao化hua方fang法fa,若ruo遇yu到dao具ju有you爭zheng議yi性xing的de結jie果guo,仍reng需xu采cai用yong國guo標biao法fa中zhong的de消xiao化hua方fang法fa進jin行xing樣yang品pin消xiao化hua和he粗cu蛋dan白bai質zhi測ce定ding。
所(suo)以(yi),相(xiang)對(dui)來(lai)說(shuo),我(wo)們(men)在(zai)進(jin)行(xing)相(xiang)關(guan)蛋(dan)白(bai)質(zhi)含(han)量(liang)測(ce)定(ding)的(de)時(shi)候(hou),應(ying)該(gai)考(kao)慮(lv)的(de)如(ru)何(he)進(jin)行(xing)測(ce)量(liang)才(cai)可(ke)以(yi)得(de)出(chu)正(zheng)確(que)的(de)結(jie)果(guo),不(bu)能(neng)自(zi)己(ji)在(zai)進(jin)行(xing)養(yang)殖(zhi)等(deng)生(sheng)產(chan)的(de)時(shi)候(hou),直(zhi)接(jie)在(zai)源(yuan)頭(tou)上(shang)出(chu)現(xian)錯(cuo)誤(wu),使(shi)得(de)自(zi)己(ji)的(de)整(zheng)個(ge)利(li)用(yong)飼(si)料(liao)進(jin)行(xing)養(yang)殖(zhi)的(de)計(ji)劃(hua)失(shi)敗(bai)。



