Shapiro F, Nir I
Department of Animal Science, Hebrew University of Jerusalem, Rehovot, Israel.
Poult Sci. 1995 Dec;74(12):2019-28. doi: 10.3382/ps.0742019.
Day-old male, meat-type chicks raised in brooder batteries were infected by orally administering an inoculum prepared from intestines of broiler chicks infected with stunting syndrome (SS). Naive controls were kept in a parallel room. The chicks were fed a commercial starter diet supplemented with two levels of enzyme preparations to 14 d of age. The experiment was continued to the age of 6 wk in order to estimate compensatory feed intake and growth. In a parallel study, digestibility of the feed was determined from 1 to 3 wk of age with control or inoculated chicks. The enzymes amylase and proteases were produced by Bacillus subtilis and Penicillium emersonii. Enzyme supplementation had no effect on feed intake, growth, or feed utilization, or on digestibility of fat, starch, protein, or energy. Because enzyme supplementation did not consistently affect performance of chicks and no interactions were observed between enzyme supplementation and infection status, data are presented for effects of infection only. Inoculation of SS-infective material reduced performance to 4 wk. Compensatory growth and feed intake were observed from the age of 4 wk onward. At the age of 6 wk the slight retardation of the inoculated chicks was not significant. On Week 1, retention of fat, starch, protein, and energy was significantly depressed in the inoculated chicks. At the age of 2 wk, retention of starch was not depressed, and at the age of 3 wk, the only consistent depression was that observed for fat. The proventriculus weight and content were consistently higher in inoculated chicks, as were the small intestine and intestinal content. The pH of the gizzard content was higher, and that of the small intestine content was lower, in the inoculated birds than in their control counterparts. Stunting syndrome infection was accompanied by a significant depression of trypsin activity in the pancreas at the age of 1 and 2 wk. At these periods, amylase and chymotrypsin were not affected. At 6 wk of age, the activities of amylase, trypsin, and chymotrypsin in the pancreas were higher in the inoculated than in the control birds. In the intestinal chime, amylase, trypsin, and chymotrypsin activities were lower in the inoculated birds on Week 1 and 2 (NS for amylase on Week 1). On Week 6, the activity of all enzymes assayed was higher in the inoculated birds (NS for amylase). It is suggested that the main factors depressing feed intake and growth in SS-infected birds are most probably beyond those of digestion.
将1日龄肉用雄性雏鸡饲养在育雏笼中，通过口服接种从感染发育迟缓综合征（SS）的肉鸡雏鸡肠道制备的接种物使其感染。未感染的对照组饲养在平行的房间。雏鸡饲喂添加了两种水平酶制剂的商业育雏日粮至14日龄。实验持续到6周龄，以评估补偿性采食量和生长情况。在一项平行研究中，在1至3周龄时测定了对照雏鸡或接种雏鸡饲料的消化率。淀粉酶和蛋白酶由枯草芽孢杆菌和艾默生青霉产生。添加酶对采食量、生长、饲料利用率或脂肪、淀粉、蛋白质或能量的消化率没有影响。由于添加酶并未持续影响雏鸡的性能，且未观察到添加酶与感染状态之间的相互作用，因此仅呈现感染的影响数据。接种SS感染性物质会使4周龄前的性能下降。4周龄后观察到补偿性生长和采食量。6周龄时，接种雏鸡的轻微生长迟缓并不显著。在第1周，接种雏鸡的脂肪、淀粉、蛋白质和能量保留率显著降低。在2周龄时，淀粉保留率未降低，在3周龄时，唯一持续降低的是脂肪保留率。接种雏鸡的腺胃重量和内容物一直较高，小肠和肠内容物也是如此。接种雏鸡的砂囊内容物pH值较高，小肠内容物pH值较低。发育迟缓综合征感染在1周龄和2周龄时伴随着胰腺中胰蛋白酶活性的显著降低。在这些时期，淀粉酶和糜蛋白酶不受影响。在6周龄时，接种雏鸡胰腺中淀粉酶、胰蛋白酶和糜蛋白酶的活性高于对照雏鸡。在第1周和第2周，接种雏鸡肠内容物中的淀粉酶、胰蛋白酶和糜蛋白酶活性较低（第1周淀粉酶无显著性差异）。在第6周，接种雏鸡中所有测定酶的活性均较高（淀粉酶无显著性差异）。有人认为，抑制感染SS雏鸡采食量和生长的主要因素很可能超出了消化因素。
