{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:31:32Z","timestamp":1787027492604,"version":"build-2736575974"},"reference-count":39,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2023,4,18]],"date-time":"2023-04-18T00:00:00Z","timestamp":1681776000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100005825","name":"USDA\/NIFA SAS award","doi-asserted-by":"publisher","award":["2020-69012-31823"],"award-info":[{"award-number":["2020-69012-31823"]}],"id":[{"id":"10.13039\/100005825","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>This study was conducted to investigate the synergistic effects of orally delivered B. subtilis-cNK-2 on vaccination with rEF-1\u03b1 against E. maxima infection in broiler chickens. Chickens were assigned into the following five groups: control (CON, no Eimeria infection), non-immunized control (NC, PBS), component 1 (COM1, rEF-1\u03b1 only), component 2 (COM2, rEF-1\u03b1 plus B. subtilis empty vector), and component 3 (COM3, rEF-1\u03b1 plus B. subtilis-NK-2). The first immunization was administered intramuscularly on day 4, and the second immunization was given one week later with the same concentration of components as the primary immunization. The immunization of B. subtilis spores (COM2 and COM3) was performed by oral administration given for 5 consecutive days a week later than the second immunization. On day 19, all the chickens except the CON group were orally challenged with E. maxima oocysts (1.0 \u00d7 104\/chicken). The results of the in vivo vaccination showed that all the chickens immunized with rEF-1\u03b1 (COM1, COM2, and COM3) produced higher (p &lt; 0.05) serum antibodies against EF-1\u03b1 on 12 days post-E. maxima infection (dpi). The COM3 group showed a significantly (p &lt; 0.05) higher average body weight gain (BWG) on 0\u20136, 6\u20139, and 0\u201312 dpi compared to those of the non-immunized chickens (NC). Immunization with rEF-1\u03b1 alone (COM1) reduced the gut lesion score on 6 dpi and the fecal oocyst shedding on 9 dpi, whereas co-administration with B. subtilis spores (COM2 or COM3) led to further reduction in the lesion score. E. maxima infection increased the expression levels of IFN-\u03b3 and IL-17\u03b2 in the jejunum, but these expressions were downregulated in the rEF-1\u03b1 immunized (COM1) group and in the groups immunized with rEF-1\u03b1 and orally treated with B. subtilis spores (COM2 or COM3) at 4 dpi. A reduced gene expression of occludin in the jejunum of the E. maxima-infected chickens on 4 dpi was upregulated following the immunization with COM2. Collectively, rEF-1\u03b1 vaccination induced significant protection against E. maxima infection in the broiler chickens, and the efficacy of rEF-1\u03b1 vaccination was further enhanced by co-administration with orally delivered B. subtilis spores expressing cNK-2.<\/jats:p>","DOI":"10.3390\/ani13081383","type":"journal-article","created":{"date-parts":[[2023,4,18]],"date-time":"2023-04-18T05:18:13Z","timestamp":1681795093000},"page":"1383","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Bacillus subtilis Expressing Chicken NK-2 Peptide Enhances the Efficacy of EF-1\u03b1 Vaccination in Eimeria maxima-Challenged Broiler Chickens"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5460-9351","authenticated-orcid":false,"given":"Youngsub","family":"Lee","sequence":"first","affiliation":[{"name":"Animal Biosciences and Biotechnology Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Inkyung","family":"Park","sequence":"additional","affiliation":[{"name":"Animal Biosciences and Biotechnology Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6004-596X","authenticated-orcid":false,"given":"Samiru S.","family":"Wickramasuriya","sequence":"additional","affiliation":[{"name":"Animal Biosciences and Biotechnology Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7755-6216","authenticated-orcid":false,"given":"Hyun S.","family":"Lillehoj","sequence":"additional","affiliation":[{"name":"Animal Biosciences and Biotechnology Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,4,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1186\/s13567-020-00837-2","article-title":"Re-Calculating the Cost of Coccidiosis in Chickens","volume":"51","author":"Blake","year":"2020","journal-title":"Vet. 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