Cawthraw Shaun A, Goddard Adam, Huby Tom, Ring Isaac, Chiverton Louise, Mueller-Doblies Doris
Department of Bacteriology, Animal and Plant Health Agency (APHA - Weybridge), New Haw, Surrey, United Kingdom.
Elanco Animal Health, Form 2, Bartley Way, Bartley Wood Business Park, Hook, United Kingdom.
Front Microbiol. 2024 Jan 15;14:1327739. doi: 10.3389/fmicb.2023.1327739. eCollection 2023.
Enteritidis and Typhimurium are the two most clinically important zoonotic serovars and vaccination of breeding and laying hens affords effective control. The use of live vaccines has proven beneficial for a number of reasons, including ease of application, protection from the first day of life onwards and initiation of a strong local immune response. Live vaccines can be applied in the drinking water from the first day of life onwards, but some rearers choose to wait until the end of the first week to ensure sufficient water consumption. However, this practice leaves the birds unprotected during the crucial first week of life, where they are most susceptible to colonization by field strains. The aim of this study was to determine if successful vaccine uptake is achieved when layer pullets are vaccinated as early as day one.
Three pullet flocks were vaccinated at 1, 2, 3 or 5 days-of-age with AviPro™ Salmonella DUO, a live vaccine containing attenuated strains of Enteritidis and Typhimurium (Elanco Animal Health, Cuxhaven, Germany). The vaccine was administered via the drinking water following manufacturer's instructions. Two days post-vaccination, 10 birds per flock were culled and caecal and liver samples taken, along with two pools of faeces per flock. Levels of vaccine strains were determined by quantitative and qualitative bacteriology.
Vaccine strains were detected in all birds from all age groups indicating successful uptake of the vaccine. Levels of the Enteritidis vaccine were higher than levels of the Typhimurium vaccine, with the latter frequently only detectable following enrichment. There was an inverse correlation between age and caecal levels of vaccines, with the highest numbers seen in birds vaccinated at 1-day-of-age. Interestingly, Enteritidis vaccine strain levels in liver samples were highest when birds were vaccinated at 5 days-of-age.
These results show that successful uptake of both vaccine strains was evident in all age groups. The earlier the chicks were vaccinated, the higher the vaccine levels in caecal contents. We therefore recommend vaccination of pullets as early as practicably possible to ensure protection against exposure to field strains.
肠炎沙门氏菌和鼠伤寒沙门氏菌是临床上最重要的两种人畜共患病血清型，对种鸡和蛋鸡进行疫苗接种可有效控制疫情。使用活疫苗已被证明有诸多益处，包括易于应用、从出生第一天起就提供保护以及引发强烈的局部免疫反应。活疫苗可从雏鸡出生第一天起通过饮水接种，但一些饲养者选择等到第一周结束，以确保雏鸡有足够的饮水量。然而，这种做法使雏鸡在生命中至关重要的第一周处于无保护状态，而这正是它们最易被野毒株定植的时期。本研究的目的是确定蛋鸡雏鸡在出生第一天就接种疫苗时是否能成功摄取疫苗。
三个雏鸡群分别在1日龄、2日龄、3日龄或5日龄时用AviPro™ 沙门氏菌双价疫苗进行接种，该疫苗是一种含有减毒肠炎沙门氏菌和鼠伤寒沙门氏菌菌株的活疫苗（德国库克斯港的英特威动物保健公司生产）。按照制造商的说明通过饮水给药。接种疫苗两天后，每个鸡群挑选10只雏鸡进行宰杀，并采集盲肠和肝脏样本，同时每个鸡群采集两份粪便样本。通过定量和定性细菌学方法测定疫苗菌株的水平。
在所有年龄组的所有雏鸡中均检测到疫苗菌株，表明疫苗摄取成功。肠炎沙门氏菌疫苗的水平高于鼠伤寒沙门氏菌疫苗的水平，后者通常只有在富集后才能检测到。疫苗的盲肠水平与雏鸡年龄呈负相关，1日龄接种的雏鸡中数量最高。有趣的是，当雏鸡在5日龄接种时，肝脏样本中的肠炎沙门氏菌疫苗菌株水平最高。
这些结果表明，所有年龄组的雏鸡都能成功摄取两种疫苗菌株。雏鸡接种疫苗越早，盲肠内容物中的疫苗水平越高。因此，我们建议在实际可行的情况下尽早对雏鸡进行接种，以确保其免受野毒株感染。
