Flachowsky G, Matthey M, Ochrimenko W I, Schneider M
Karl-Marx-University Leipzig, School of Animal Production and Veterinary Medicine, Department of Animal Nutrition-Chemistry, Jena, GDR.
Arch Tierernahr. 1988 May;38(5):431-9. doi: 10.1080/17450398809428309.
The influence of type of diet and time after feeding on concentration of isoacids in rumen fluid of 6 fistulated sheep were investigated. The concentration of isoacids in rumen fluid was higher in diets rich in concentrate and protein (5.6) than in roughage diets (3.4) or in straw-starch-urea diets poor in native protein (highest concentration: 2.1 mmol/l rumen fluid). Feeding of roughage diet or straw-starch-urea-diet effected a significant decrease of concentration of isoacids in the rumen fluid after morning feeding, but concentrate-roughage diet, increased the isoacids-concentration. Reasons for decreased concentration of isoacids may be a shortage of corresponding amino acids and a high activity of cellulolytic microbes. Infusion of isoacids (3 g per day) in the rumen of sheep fed with a straw-starch-sugar-urea diet did not significantly influence the in sacco dry matter degradability of untreated wheat straw, but increased the dry matter loss of ammonia treated wheat straw from 16.0; 26.6; 39.4; 54.0 and 58.8% to 17.3; 29.7; 43.1; 56.3 and 63.0% after 6; 12; 24; 48 and 72 h rumen incubation time respectively. Further experiments seem to be necessary. The effect of isoacids may be expected to occur with poor quality feeds, rich in fibre low in protein and hence low in branched-chain amino acids.
研究了日粮类型和采食后时间对6只安装瘤胃瘘管绵羊瘤胃液中异酸浓度的影响。富含精料和蛋白质的日粮（5.6）中瘤胃液异酸浓度高于粗饲料日粮（3.4）或天然蛋白质含量低的秸秆-淀粉-尿素日粮（最高浓度：2.1 mmol/L瘤胃液）。饲喂粗饲料日粮或秸秆-淀粉-尿素日粮会使晨饲后瘤胃液中异酸浓度显著降低，但精料-粗饲料日粮会提高异酸浓度。异酸浓度降低的原因可能是相应氨基酸短缺和纤维素分解微生物活性高。向饲喂秸秆-淀粉-糖-尿素日粮的绵羊瘤胃中注入异酸（每天3 g）对未处理小麦秸秆的瘤胃内干物质降解率没有显著影响，但将氨处理小麦秸秆在瘤胃培养6、12、24、48和72 h后的干物质损失从16.0%、26.6%、39.4%、54.0%和58.8%分别提高到17.3%、29.7%、43.1%、56.3%和63.0%。似乎有必要进行进一步实验。异酸的作用可能在质量差、富含纤维、蛋白质含量低且因此支链氨基酸含量低的饲料中出现。
