甲醛处理对菜籽饼蛋白质瘤胃降解和氮利用效率的影响

EFFECTS OF FORMALDEHYDE TREATMENT ON RUMINAL DEGRADATION AND NITROGEN UTILIZATION OF RAPESEED MEAL BY HU-YANG SHEEP

试验一:用三头装有永久瘤胃瘘管的湖羊,采有尼龙袋法测定了菜籽饼经四种不同浓度甲醛处理后,其蛋白质的瘤胃内降解率。甲醛处理显著降低了菜籽饼蛋白质的瘤胃降解率(P<0.01),随甲醛处理浓度的增大,菜籽饼蛋白降解率直线下降。C(对照组),0.3％、0.6％和0.9％(甲醛用量/菜籽饼粗蛋白量,HCHO/CP)处理的菜籽饼,其蛋白质降解率分别为61.7％、55.9％、49.5％、38.9％。分析试验结果发现,甲醛处理使菜籽饼蛋白降解率降低的主要原因是快速降解部分蛋白质的降低而引起。试验二:用这四种甲醛浓度处理的菜籽饼作为湖羊的蛋白补充料,按4×4拉丁方设计进行了氮平衡试验。经甲醛处理后,粪氮排出量有增加趋势,但尿氮排出量减少,其结果甲醛处理组的氮沉积高于对照组,其中0.6％(HCHO/CP)处理菜籽饼羊的氮沉积量最高,并显著高于对照组(P<0.05)。上述结果表明,甲醛处理菜籽饼的浓度以占菜籽饼粗蛋白质的0.6％为适宜。

Two trials were carried out to study the effects of fomaldehyed (HCHO) treatment on ruminal degradation (trial 1) and utilization of nitrogen (N) (trial 2) of rapeseed meal (RSM) for Hu-Yang Sheep. Rapeseed meal was treated with HCHO at levels of 0％, 0.3％, 0.6％ or 0.9％ of crude protein (CP) of RSM. Three lambs fitted with rumen cannula were used to determine the ruminal protein degradability of RSM treated with HCHO at different levels with in sacco technique. The ruminal degradability of RSM protein decreased significantly (P<0.01) with the increasing level of HCHO, and were 67.7, 58.9, 49.5 and38.9％ at level of 0％, 0.3％, 0.6％ and 0.9％ HCHO/CP, respectively. The reduced protein degadability of HCHO treated RSM was mainly resultant from the decrease in the fast degradable fraction. Trial 2 was conducted to determine N balance in lambs given HCHO-treated RSM at four levels as described above, to evaluate the utilization efficiency of HCHO-treated RSM. With the increasing level of HCHO, fecal N increased while urinary N loss decreased, resulting in the increased N retention in lambs given the HCHO-treated RSM, compared with those on the untreated RSM. The animals offered HCHO-treated RSM at the level of 0.6％ (HCHO/CP) showed the highest N retention and ha significantly (P<0.05) higher N retention than those on the untreated RSM. These results suggest that formaldeyde treatment can decrease ruminal degradability of RSM protein, and that an appropriate HCHO level to treat RSM is at 0.6％ (HCHO/CP).