title: Effects of threonine supplementation on the growth performance, immunity, oxidative status, intestinal integrity, and barrier function of broilers at the early age.
abstract: The aim of this study was to investigate effects of L-threonine (L-Thr) supplementation on the growth performance, immunity, antioxidant status, and intestinal health of broilers at the early age. One hundred and forty-four 1-day-old male broiler chicks (Arbor Acres Plus) were allocated into 3 treatments with 6 replicates of 8 birds each, and fed a basal diet (analyzed Thr content, 7.87 g/kg) supplemented with 0 (control diet), 1 and 3 g/kg L-Thr for 21 d, respectively. Treatments did not alter growth performance of broilers. Compared with control, 1 g/kg Thr supplementation increased relative weight of spleen (P = 0.013). A higher level of Thr (3 g/kg) increased relative weight of thymus (P = 0.003). The supplementation of 3 g/kg Thr reduced Escherichia coli (P = 0.040) and Salmonella colonies (P = 0.015), whereas increased Lactobacillus colonies (P < 0.001) in the cecal contents. Thr supplementation increased intestinal villus height (P < 0.05), and the ratio of villus height to crypt depth (P < 0.001), and the values for these parameters were intermediate with 1 g/kg Thr. Goblet cell density was increased by Thr supplementation (P < 0.001). The jejunal immunoglobulin G content was increased by the inclusion of Thr (P = 0.002). Broilers fed diet supplemented with 1 g/kg Thr exhibited increased concentrations of jejunal immunoglobulin M (P = 0.037) and secretory immunoglobulin A (P = 0.018). Likewise, 3 g/kg Thr inclusion increased ileal secretory immunoglobulin A content (P = 0.023). The jejunal malondialdehyde accumulation was reduced by Thr inclusion (P = 0.012). A higher level of Thr inclusion also reduced malondialdehyde content in the serum (P = 0.029). The high level of Thr inclusion (3 g/kg) upregulated mucin-2 mRNA expression (P = 0.034), whereas downregulated the mRNA abundances of interferon-γ (P = 0.036) and interleukin-1β (P = 0.031) in the ileum. In conclusion, L-Thr supplementation can improve immunity, antioxidant capacity, and intestinal health of broilers at an early age.
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China.
authors.forename: Y P
authors.initials: YP
authors.lastname: Chen
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China.
authors.forename: Y F
authors.initials: YF
authors.lastname: Cheng
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China.
authors.forename: X H
authors.initials: XH
authors.lastname: Li
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China.
authors.forename: W L
authors.initials: WL
authors.lastname: Yang
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China.
authors.forename: C
authors.initials: C
authors.lastname: Wen
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China.
authors.forename: S
authors.initials: S
authors.lastname: Zhuang
authors.affiliation: College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, P. R. China zhouym6308@163.com.
authors.forename: Y M
authors.initials: YM
authors.lastname: Zhou
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002645:Chickens / Q000033:anatomy & histology / Q000254:growth & development / Q000276:immunology / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements / Q000032:analysis; D007422:Intestines / Q000187:drug effects*; D008297:Male; D011897:Random Allocation; D013912:Threonine / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D013912:Threonine
keywords: broilers; immunity; intestinal integrity; oxidative status; threonine