Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762.
Department of Poultry Science, Mississippi State University, Mississippi State, MS 39762.
Poult Sci. 2021 Jun;100(6):101125. doi: 10.1016/j.psj.2021.101125. Epub 2021 Mar 11.
Recent research has tried to maximize broiler chick health and performance by utilizing commercial in-feed probiotics to inoculate fertile hatching eggs, and thus expose birds earlier to beneficial bacteria. However, the in ovo inoculation of a specific serotype of Bacillus subtilis was detrimental for broiler hatchability. Therefore, the objective of this study was to determine if other B. subtilis serotypes negatively affect hatchability or if it is associated with a specific serotype. It was also of interest to determine if the B. subtilis serotype influence chick performance and intestinal microflora. On d18 of incubation, 1886 fertile broiler eggs were in ovo inoculated with the following treatments (T): T1 = Marek's vaccine (MV), T2 = MV + B. subtilis (ATCC 6051), T3 = MV + B. subtilis (ATCC 8473), and T4 = MV + B. subtilis (ATCC 9466). It should be noted that in a previous study, T2 was detrimental to hatchability. Inoculated eggs were transferred to 3 hatchers/T. At hatch, chicks were weighed, feather sexed, and hatch residue analysis was conducted. Male chicks were randomly assigned to 40 raised wire cage so that there were 10 birds/cage. On d 0, 7, 14, and 21 of the grow-out, chicks and feed were weighed to calculate performance data. On these days, the ileum and ceca were aseptically collected to enumerate total aerobes and coliforms. No differences were observed for percentage of mid dead embryos, cracked eggs, and cull chicks (P > 0.05). However, hatch of transfer was significantly reduced by T2 compared to T1, T3, and T4 (P < 0.001). T2 had significantly higher percentages of late dead embryos and pips when compared to the other treatments (P = 0.002 and P < 0.001, respectively). Chicks hatched from T2 were not vigorous and, thus, not used for the grow-out trial. No differences were observed for growth performance characteristics for any of the treatments (P > 0.05). For bacterial enumeration, the ileum had equal or fewer bacterial counts for T3 and T4 when compared to T1 on most sampling days, except on d21 where T4 had higher aerobic and coliform counts (P ≤ 0.0001). For the ceca, T3 and T4 had equal or fewer bacterial counts than T1 on every sampling day (P ≤ 0.0001). These data demonstrate that not all B. subtilis evaluated are detrimental to hatchability, but rather, serotype dependent. In addition, different B. subtilis serotypes can modify the intestinal microflora with potential to reduce pathogenic bacteria present in young broiler, without impacting overall performance.
最近的研究试图通过利用商业饲料益生菌来接种可孵化的种蛋，从而使禽类更早地接触有益细菌，从而最大限度地提高肉鸡雏鸡的健康和性能。然而，在卵内接种特定血清型枯草芽孢杆菌对肉鸡孵化率有不利影响。因此，本研究的目的是确定其他枯草芽孢杆菌血清型是否会降低孵化率，或者是否与特定血清型有关。是否枯草芽孢杆菌血清型会影响雏鸡的性能和肠道微生物群也很有趣。在孵化的第 18 天，1886 枚有活力的肉鸡种蛋被卵内接种以下处理（T）：T1=马立克氏疫苗（MV），T2=MV+枯草芽孢杆菌（ATCC 6051），T3=MV+枯草芽孢杆菌（ATCC 8473）和 T4=MV+枯草芽孢杆菌（ATCC 9466）。值得注意的是，在之前的一项研究中，T2 对孵化率不利。接种的种蛋被转移到 3 个孵化机/T 中。孵化时，雏鸡称重、羽毛性别鉴定，并进行孵化残渣分析。雄性雏鸡被随机分配到 40 个高架铁丝笼中，每个笼中有 10 只鸡。在生长结束时的第 0、7、14 和 21 天，雏鸡和饲料称重以计算性能数据。在这些日子里，无菌采集回肠和盲肠以计数需氧菌和大肠菌群。中期死胚、裂纹蛋和淘汰雏鸡的比例没有差异（P＞0.05）。然而，与 T1、T3 和 T4 相比，T2 中转机孵化率显著降低（P＜0.001）。与其他处理相比，T2 的晚期死胚和出雏率显著更高（P=0.002 和 P＜0.001）。从 T2 孵化的雏鸡活力不足，因此不用于生长试验。任何处理的生长性能特征都没有差异（P＞0.05）。对于细菌计数，除了第 21 天外，T3 和 T4 在大多数采样日的回肠细菌计数与 T1 相等或更少，而 T4 在第 21 天的需氧菌和大肠菌群计数更高（P≤0.0001）。对于盲肠，T3 和 T4 在所有采样日的细菌计数均与 T1 相等或更少（P≤0.0001）。这些数据表明，并非所有评估的枯草芽孢杆菌都对孵化率有害，而是取决于血清型。此外，不同的枯草芽孢杆菌血清型可以改变肠道微生物群，有可能减少幼肉鸡中的致病性细菌，而不会影响整体性能。
