title: Effects of dietary addition of heat-killed Mycobacterium phlei on growth performance, immune status and anti-oxidative capacity in early weaned piglets.
abstract: The contradiction between high susceptibility of early weaned piglets to enteric pathogens and rigid restriction of antibiotic use in the diet is still prominent in the livestock production industry. To address this issue, the study was designed to replace dietary antibiotics partly or completely by an immunostimulant, namely heat-killed Mycobacterium phlei (M. phlei). Piglets (n = 192) were randomly assigned to one of the four groups: (1) basal diet (Group A), (2) basal diet + a mixture of antibiotics (80 mg/kg diet, Group B), (3) basal diet + a mixture of antibiotics (same as in Group B, but 40 mg/kg diet) + heat-killed M. phlei (1.5 g/kg diet) (Group C) and (4) basal diet + heat-killed M. phlei (3 g/kg diet) (Group D). All piglets received the respective diets from days 21 to 51 of age and were weaned at the age of 28 d. Compared with the Control (Group A), in all other groups the average daily gain, average daily feed intake, small intestinal villus height:crypt depth ratio and protein levels of occludin and ZO-1 in the jejunal mucosa were increased. A decreased incidence of diarrhoea in conjunction with an increased sIgA concentration in the intestinal mucosa and serum IL-12 and IFN-γ concentrations was found in groups supplemented with heat-killed M. phlei (Groups C and D), but not in Group B. Groups C and D also showed decreased IL-2 concentrations in the intestinal mucosa with lower TLR4 and phosphor-IκB protein levels. The antioxidant capacity was reinforced in Groups C and D, as evidenced by the reduction in malondialdehyde and enhanced activities of antioxidant enzymes in serum. These data indicate that heat-killed M. phlei is a promising alternative to antibiotic use for early weaned piglets via induction of protective immune responses.
authors.affiliation: a College of Animal Science and Technology , Hunan Agricultural University , Changsha , China.|b Hunan Co-Innovation Center of Animal Production Safety , Changsha , China.|c Hunan Polytechnic of Environment and Biology , Hengyang , China.
authors.forename: Jin-Feng
authors.initials: JF
authors.lastname: Zhong
authors.affiliation: c Hunan Polytechnic of Environment and Biology , Hengyang , China.
authors.forename: Wei-Gao
authors.initials: WG
authors.lastname: Wu
authors.affiliation: d Grassland Research Institute , Chinese Academy of Agricultural Sciences , Hohhot , China.
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Zhang
authors.affiliation: a College of Animal Science and Technology , Hunan Agricultural University , Changsha , China.|b Hunan Co-Innovation Center of Animal Production Safety , Changsha , China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tu
authors.affiliation: c Hunan Polytechnic of Environment and Biology , Hengyang , China.
authors.forename: Zhen-Xiang
authors.initials: ZX
authors.lastname: Liu
authors.affiliation: a College of Animal Science and Technology , Hunan Agricultural University , Changsha , China.|b Hunan Co-Innovation Center of Animal Production Safety , Changsha , China.
authors.forename: Re-Jun
authors.initials: RJ
authors.lastname: Fang
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements / Q000032:analysis; D004306:Dose-Response Relationship, Immunologic; D004734:Energy Metabolism; D006358:Hot Temperature; D007113:Immunity, Innate / Q000187:drug effects*; D018928:Immunity, Mucosal / Q000187:drug effects*; D056747:Immunomodulation; D007421:Intestine, Small / Q000033:anatomy & histology / Q000187:drug effects; D009168:Mycobacterium phlei / Q000737:chemistry*; D018384:Oxidative Stress / Q000187:drug effects; D011897:Random Allocation; D034421:Sus scrofa / Q000254:growth & development / Q000276:immunology / Q000502:physiology*; D014886:Weaning
chemical_list: D000276:Adjuvants, Immunologic; D000975:Antioxidants
keywords: Antibiotics; Mycobacterium phlei; diarrhoea; early weaning; immune system; performance; piglets