Hume M E, Corrier D E, Nisbet D J, DeLoach J R
U.S. Department of Agriculture, Food Animal Protection Research Laboratory, College Station, Texas 77845, USA.
J Food Prot. 1998 Jun;61(6):673-6. doi: 10.4315/0362-028x-61.6.673.
Broiler chicks were treated by oral gavage on the day of hatch with a continuous-flow competitive exclusion culture (PREEMPT). At 4 h, 1 day, or 2 days posttreatment, chicks were challenged by oral gavage with 10(2) or 10(4) Salmonella CFU to determine the effects of challenge time on Salmonella cecal colonization. Cecal propionic acid concentrations in two trials increased (P < or = 0.001) within 1 day posttreatment in chicks given PREEMPT, and the increases were indicative of the establishment of the PREEMPT bacteria. Salmonella cecal populations decreased (P < or = 0.001) on average 6 log10 units in these two trials in chicks challenged 4 h posttreatment with 10(4) Salmonella CFU. In a third trial propionic acid did not increase significantly until 2 days after treatment, and there was no decrease in Salmonella colonization when chicks were challenged at 4 h after treatment. However, there were decreases in that same trial when chicks were challenged at 1 and 2 days after treatment. The early establishment of PREEMPT followed by challenges with 10(2) and 10(4) Salmonella CFU resulted in 3% and 3%, respectively, of the ceca testing Salmonella-culture-positive, compared to 28% and 95%, respectively, culture-positive ceca in untreated chicks. The results from this study indicated that in most instances young broiler chicks can be protected against cecal colonization when challenged with 10(2) and 10(4) Salmonella CFU as early as 4 h posttreatment on the day of hatch with the PREEMPT bacteria.
在雏鸡出壳当天，通过口服灌胃给予其连续流动竞争排斥培养物（PREEMPT）进行处理。在处理后4小时、1天或2天，通过口服灌胃用10²或10⁴个沙门氏菌CFU对雏鸡进行攻毒，以确定攻毒时间对沙门氏菌盲肠定植的影响。在两项试验中，给予PREEMPT的雏鸡在处理后1天内盲肠丙酸浓度升高（P≤0.001），这种升高表明PREEMPT细菌已定植。在这两项试验中，用10⁴个沙门氏菌CFU在处理后4小时对雏鸡进行攻毒，沙门氏菌盲肠菌量平均减少（P≤0.001）6个对数10单位。在第三项试验中，丙酸直到处理后2天才显著升高，当雏鸡在处理后4小时进行攻毒时，沙门氏菌定植没有减少。然而，在同一试验中，当雏鸡在处理后1天和2天进行攻毒时，沙门氏菌定植减少。先用PREEMPT进行早期定植，随后用10²和10⁴个沙门氏菌CFU进行攻毒，结果分别有3%和3%的盲肠沙门氏菌培养呈阳性，相比之下，未处理的雏鸡盲肠培养阳性率分别为28%和95%。本研究结果表明，在大多数情况下，雏鸡出壳当天用PREEMPT细菌处理后，早在处理后4小时用10²和10⁴个沙门氏菌CFU进行攻毒时，雏鸡可免受盲肠定植。
