利用体外法研究不同水平维生素A对奶牛瘤胃内环境参数的影响

Effects of Different Levels of VA on the Ruminal Environmental Parameters in Holstein Cows in Vitro

本研究以3只安装有永久性瘤胃瘘管的荷斯坦奶牛作为试验动物,利用体外培养法研究3个不同水平的VA(分别为8.3×10-2mg/mL(A组)、2.5×10-1mg/mL(B组)和4.17×10-1mg/mL(C组))对瘤胃pH、氨氮(NH3-N)、尿素氮和挥发性脂肪酸(VFA)浓度随时间的动态变化的影响以及VA在瘤胃中的消失情况。结果表明,随着VA添加量的增加培养液pH呈上升趋势,NH3-N和VFA的平均浓度呈下降趋势,但差异不显著(P>0.05)。C组培养液尿素氮浓度极显著高于A、B两组(P<0.01)。在高产奶牛的TMR日粮条件下,培养液VA浓度随着VA添加量的增加而增加,且不同VA水平下,培养液中VA浓度的峰值均出现在培养8 h后。

To study the effects of different levels of VA on the ruminal environmental parameters in vitro, three Holstein cows fitted with the ruminal cannula were used to determine the effects of VA on pH, ammonia-N （NH3-N）, urea-N, volatile fatty acids （VFA） concentration in culture fluid in vitro. Three levels of VA were 8.3 × 10^-2 mg/mL （A）. 2.5 × 10^-1 mg/mL （B）, 4.17 × 10^-1 mg/mL （C） respectively. The results showed 1） pH increased, as well as NH3-N and urea-N concentration in culture fluid decreased with the increase of VA. There were no significant differences in pH. NH3-N concentration among three levels of VA （P〈0.05）; 2） the highest urea-N concentration was observed in level C. much higher than that in level A and B （P〈0.01） ; 3） higher VA supplement increased the VA concentration of culture fluid. Little VA was detected during 0-8 h of incubation. The highest VA concentration were observed after incubating 8 h in culture fluid. [Chinese Journal of Animal Nutrition, 2006,18（3） ： 197-202 ]