桑叶DNJ对家兔肠道消化功能的影响

Effects of Mulberry Leaf DNJ on Intestinal Digestive Function of Rabbits

[目的]研究桑叶1-脱氧野尻霉素(DNJ)对家兔肠道消化功能的影响,分析其是否是限制桑叶在家兔饲料中使用量的因素。[方法]36只体重相近的健康新西兰白兔随机分为3组,对照组饲喂基础日粮,处理组在基础日粮中分别添加DNJ 0.4和2.0 g/kg,预试期7 d,正试期42 d。第30天每组选8只试验兔放入代谢笼进行消化率试验,收集粪便和饲料检测营养成分。试验结束时电击休克处死家兔,采集十二指肠、空肠和盲肠内容物检测消化酶活性,以及盲肠pH、氨态氮和挥发性脂肪酸浓度。[结果]桑叶DNJ降低了新西兰白兔干物质和粗脂肪的消化率、十二指肠淀粉酶活性以及盲肠pH和氨态氮浓度,提高了盲肠丁酸浓度(P<0.05);高剂量DNJ(2.0 mg/g)提高了新西兰白兔粗蛋白消化率以及盲肠乙酸和总挥发性脂肪酸浓度,降低空肠淀粉酶活性(P<0.05);DNJ对新西兰白兔粗纤维消化率和蛋白酶活性、纤维素酶活性以及盲肠丙酸浓度无显著影响(P>0.05)。[结论]桑叶DNJ可抑制家兔对能量物质脂肪和淀粉的利用,不利于动物育肥,不可在饲料中大量使用;但DNJ能够提高家兔对蛋白质的利用率,减少含氮物排泄,且能增强盲肠微生物发酵,因此可将桑叶作为调节家兔肠道健康和减少氮排放的功能饲料利用。

[Objective]To study the effect of 1-deoxidization(DNJ)from mulberry leaf on intestinal digestive function of rabbits,and analyze whether it was the factor limiting the usage of mulberry leaf in rabbit feed.[Method]Thirty-six healthy New Zealand white rabbits with similar body weight were randomly divided into 3 groups.The control group was fed a basal diet,and the treatment groups were fed a basal diet sup-plemented with DNJ 0.4 g/kg and 2.0 g/kg,respectively.The pre-trial period lasted for 7 d,and the trial period lasted for 42 d.At the fifth week,8 rabbits in each group were put into metabolic cage for digestibility test,feces and feed were collected for nutrient composition detec-tion.At the end of the experiment,rabbits were killed by electric shock.Duodenum,jejunum and cecum contents were collected to detect di-gestive enzyme activities,and pH,ammonia nitrogen and volatile fatty acid concentration of cecum contents were detected.[Result]Mulberry leaf DNJ decreased the digestibility of dry matter and crude fat,duodenal amylase activity,cecal pH and ammonia nitrogen concentration,and increased the cecal butyric acid concentration(P<0.05).High dose DNJ(2.0 mg/g)increased crude protein digestibilityand cecal acetic acid and total volatile fatty acid concentrations in New Zealand white rabbits,decreased jejunal amylase activity(P<0.05).DNJ had no significant effects on crude fiber digestibility,protease activity,cellulase activity and caecal propionic acid concentration of New Zealand white rabbits(P>0.05).[Conclusion]DNJ from mulberry leaf can inhibit the utilization of energy substances,such as fat and starch,in rabbits,which is not conducive to animal fattening.However,DNJ can improve the utilization rate of protein,reduce nitrogen excretion,and enhance cecal mi-crobial fermentation.Therefore,mulberry leaves can be used as functional feed to regulate intestinal health and reduce nitrogen emission of rabbits.