不同加工工艺对玉米纤维饲料营养价值的影响

本试验以干玉米纤维饲料(DCGF)和湿玉米纤维饲料(WCGF)为原料,分析加工工艺对玉米纤维饲料营养价值的影响。选取3头装有永久性瘤胃瘘管的干奶期荷斯坦奶牛为试验动物,采用常规方法测定DCGF和WCGF营养成分含量,采用尼龙袋法测定瘤胃降解特性,采用三步体外法测定瘤胃非降解蛋白质(RUP)的小肠消化率,采用NRC模型预测代谢蛋白质和必需氨基酸供给量。结果表明:1)DCGF常规营养成分中除中性洗涤纤维(NDF)、中性洗涤不溶粗蛋白质(NDICP)、酸性洗涤不溶粗蛋白质(ADICP)含量显著高于WCGF(P0.05)外,其他营养成分含量均差异不显著(P0.05);2)DCGF和WCGF的瘤胃NDF降解率差异不显著(P0.05),而DCGF的瘤胃干物质(4、24、48 h)、粗蛋白质(CP)降解率(12、24、48和72 h)及有效降解率显著低于WCGF(P0.05);3)DCGF的RUP含量显著高于WCGF(P0.05),而总可消化养分和微生物蛋白质、代谢蛋白质含量与DCGF差异不显著(P0.05);4)DCGF的RUP的小肠消化率显著低于WCGF(P0.05),但总可消化蛋白质含量差异不显著(P0.05);5)饲料RUP提供的必需氨基酸中,DCGF的RUP提供的组氨酸(His)、苯丙氨酸(Phe)、异亮氨酸(Ile)以及总必需氨基酸含量显著高于WCGF(P0.05)。综合得出,DCGF和WCGF都含有高含量的可利用纤维和蛋白质,可以作为奶牛良好的纤维和蛋白质源饲料,但DCGF的瘤胃CP降解率和RUP的小肠消化率较低,可能影响其蛋白质和氨基酸的营养价值。

Effects of Different Processing Techniques on Nutritional Value of Corn Gluten Feed

This trail was conducted to evaluate the effects of processing technology on the nutritional value of corn gluten feed using wet corn gluten feed ( WCGF) and dry corn gluten feed ( DCGF) as ingredients. Three ruminally cannulated Holstein cows in dry period were selected as experimental animals. Nutrient composition contents of DCGF and WCGF were determined by common methods, nylon-bag technique was used to evaluate rumen degradation characteristics of DCGF and WCGF, intestinal digestibility of rumen undegraded protein ( RUP) of DCGF and WCGF was determined using in vitro three steps method, and NRC model was used to determine supplemental amounts of metabolizable protein and essential amino acids. The results showed as fol-lows:1) except contents of neutral detergent fiber( NDF) , neutral detergent insoluble crude protein ( NDICP) and acid detergent insoluble crude protein ( ADICP) , nutrient contents of DCGF and WCGF were not signifi-cantly different (P>0.05). 2) Compared with WCGF, dry matter (DM) (4, 24 and 48 h) and crude protein (CP) degradability (12, 24, 48 and 72 h) of DCGF were lower significantly (P<0.05), but NDF degrad-ability was not significantly different between two feeds ( P>0.05) . 3) RUP content of DCGF was significantly higher than that of WCGF ( P<0.05) , and there were no significant differences of contents of total digestible nutrients, microbial protein and metabolism protein between two feeds ( P>0.05) . 4) Compared with WCGF, intestinal digestion of RUP of DCGF was significantly lower (P<0.05), but total digestible protein was not significantly different (P>0.05). 5) Among essential amino acids provided by RUP, contents of histidine, phenylalanine, isoleucine and total essential amino acids provided by RUP of DCGF were significantly higher than those of WCGF ( P<0.05) . In conclusion, there are high contents of available fiber and protein in DCGF and WCGF, which can be used as fiber and protein feed for dairy cows, but low degradability of CP and small intestinal digestibility of RUP of DCGF may affect their nutritional values of protein and amino acids.