This study investigated various levels of sodium nitrite and probiotics (SNPro) combination as an alternative to zinc oxide on the growth performance, immune response, intestinal microflora, and morphology of weaned pigs. One hundred and ninety-two weaned pigs (Landrace×Yorkshire×Duroc) with an average body weight of 6.51±0.15 kg were randomly assigned to four treatments(n=6) on the basis of their initial body weight. Experimental period was divided into phase 1 and 2 (each 14 days). The dietary treatments were: 1) Basal diet (control), 2) SNPro1 (control+0.01% SNPro), 3) SNPro2 (control+0.02% SNPro), 4) SNPro3 (control+0.03% SNPro). The average daily gain when SNPro was added to the diet was 288, 309, 319, 324 g in phase 1, 355, 387, 410, 407 g in phase 2 and 321, 348, 364, 366 g in the overall. The concentration of interleukin-8 and interleukin-10 in serum when SNPro was added to the diet were 15, 13.5, 13, 12.8 ng/ml and 165, 162, 155, 145 ng/ml (p<0.05) but toll-like receptor 4 and immunoglobulin G levels in serum were no significantly different. The colonization of Escherichia coli in the ileum and Salmonella spp. in the caecum were significantly decreased as SNPro level increased (p<0.05). However, the population of Lactobacillus spp. did not differ among the groups. Although villus height and villus height to crypt depth ratio were not significantly affected by the treatments, crypt depth in the jejunum was 599, 586, 615, 599 ㎛ as SNPro level increased (p<0.05). In conclusion, SNPro had beneficial effects on growth performance, immune response, intestinal microflora and morphology weaned pigs. Therefore, SNPro not only can be considered as an alternative for the pharmacological level of zinc oxide in weaning pigs but also ideal dietary SNPro level was 0.02%.

ABSTRACT
Ⅰ. 서론
Ⅱ. 재료 및 방법
    1. 공시동물 및 실험설계
    2. 실험사료와 사양관리
    3. 조사항목
Ⅲ. 결과 및 고찰
    1. 사양성적
    2. 면역 반응
    3. 장 내 미생물
    4. 장 내 융모 성상
Ⅳ. 요약
Ⅴ. 참고문헌

• 문준영(강원대학교 바이오헬스융합학과) | Jun-Young Mun (Department of Bio-Health Convergence, Kangwon National University)
• 최요한(농촌진흥청 국립축산과학원 양돈과) | Yo-Han Choi (Swine Science Division, National Institute of Animal Science, R.D.A.)
• 하상훈(강원대학교 바이오헬스융합학과) | Sang-Hun Ha (Department of Bio-Health Convergence, Kangwon National University)
• Joseph Moturi(강원대학교 바이오헬스융합학과)
• Tajudeen Habeeb(강원대학교 바이오헬스융합학과)
• 김조은(농촌진흥청 국립축산과학원 양돈과) | Jo-Eun Kim (Swine Science Division, National Institute of Animal Science, R.D.A.) Corresponding author
• 김진수(강원대학교 바이오헬스융합학과) | Jin-Soo Kim (Department of Bio-Health Convergence, Kangwon National University) Corresponding author