Liang Y S, Li G Z, Li X Y, Lü J Y, Li F D, Tang D F, Li F, Deng Y, Zhang H, Wang Z L, Weng X X
J Anim Sci. 2017 Apr;95(4):1727-1738. doi: 10.2527/jas.2016.1134.
The objective of this study was to evaluate the effect of residual feed intake (RFI) on rumen function in finishing lambs. A total of 60 male Hu lambs (average initial BW = 25.2 ± 2.5kg) were used and were offered a pelleted high-concentrate diet, of which the forage to concentrate ratio was 25:75. Individual feed intake was recorded over a period of 42 d, then 10 lambs with the lowest RFI and the highest RFI were selected, respectively. The rumen fluid used for fermentation variables and relative abundance of bacteria measurement was obtained on d 10 and 20 after RFI measurement. At the end of this experiment, the selected lambs were slaughtered and rumen epithelium and liver tissues were collected for RNA extraction. Low-RFI lambs had lower ( < 0.01) DMI and greater ( < 0.05) G:F than the high-RFI ones, while the RFI groups did not differ in ADG and BW ( > 0.05). Additionally, RFI was positively ( = 0.57; < 0.01) correlated with DMI and negatively ( = -0.53; < 0.05) correlated with G:F. Total VFA and individual VFA decreased ( < 0.05) over time. The concentrations of total VFA, acetate, valerate, isobutyrate, isovalerate, and rumen pH ( > 0.05) were not affected by RFI classification. Nonetheless, low-RFI group lambs had a greater ( < 0.05) concentration of propionate, a lower ( < 0.05) concentration of butyrate, and a lower ( < 0.05) acetate to propionate ratio compared with the high-RFI group. There was a significant ( < 0.05) effect of RFI on the relative abundance of and . The relative abundance of , , and decreased ( < 0.05) over time in high-RFI group. And the relative abundance of in high-RFI group was greater ( < 0.05) than its low-RFI counterpart. Furthermore, RFI had no effect ( > 0.05) on gene expression associated with intracellular pH regulation (, , , , , , , and ) in rumen epithelium and β-hydroxybutyrate metabolism () in both rumen epithelium and liver tissues. In conclusion, even though low-RFI lambs had lower DMI, however, the number of was lower. Additionally, there was no difference in gene expressions level associated with intracellular pH regulation in rumen epithelium between RFI groups.
本研究的目的是评估剩余采食量（RFI）对育肥羔羊瘤胃功能的影响。总共使用了60只雄性湖羊羔羊（初始平均体重=25.2±2.5千克），给它们提供颗粒状高浓缩日粮，其中粗饲料与精饲料的比例为25:75。在42天的时间内记录个体采食量，然后分别挑选出10只RFI最低和最高的羔羊。用于测量发酵变量和细菌相对丰度的瘤胃液在RFI测量后的第10天和第20天采集。在本实验结束时，将挑选出的羔羊屠宰，并采集瘤胃上皮和肝脏组织用于RNA提取。低RFI组羔羊的干物质采食量（DMI）低于高RFI组（P<0.01），饲料转化率（G:F）高于高RFI组（P<0.05），而RFI组之间的平均日增重（ADG）和体重（BW）没有差异（P>0.05）。此外，RFI与DMI呈正相关（r=0.57；P<0.01），与G:F呈负相关（r=-0.53；P<0.05）。总挥发性脂肪酸（VFA）和各单个VFA随时间下降（P<0.05）。总VFA、乙酸、戊酸、异丁酸、异戊酸的浓度以及瘤胃pH值不受RFI分类的影响（P>0.05）。尽管如此，与高RFI组相比，低RFI组羔羊的丙酸浓度更高（P<0.05），丁酸浓度更低（P<0.05），乙酸与丙酸的比例更低（P<0.05）。RFI对[具体细菌名称1]和[具体细菌名称2]的相对丰度有显著影响（P<0.05）。在高RFI组中，[具体细菌名称3]、[具体细菌名称4]和[具体细菌名称5]的相对丰度随时间下降（P<0.05）。并且高RFI组中[具体细菌名称6]的相对丰度高于低RFI组（P<0.05）。此外，RFI对瘤胃上皮中与细胞内pH调节相关的基因表达（[相关基因名称1]、[相关基因名称2]、[相关基因名称3]、[相关基因名称4]、[相关基因名称5]、[相关基因名称6]、[相关基因名称7]和[相关基因名称8]）以及瘤胃上皮和肝脏组织中β-羟基丁酸代谢（[相关基因名称9]）均无影响（P>0.05）。总之，尽管低RFI组羔羊的DMI较低，但[具体细菌名称7]的数量较少。此外，RFI组之间瘤胃上皮中与细胞内pH调节相关的基因表达水平没有差异。
