title: The addition of protein-bound amino acids in low-protein diets improves the metabolic and immunological characteristics in fifteen- to thirty-five-kg pigs.
abstract: This study was to evaluate the effects of supplementation of AA form (crystalline vs. protein bound) in low-protein diets on growth, metabolic, and immunological characteristics of pigs. A total of 80 barrows (PIC 327 × 1050; 15.57 ± 0.13 kg BW and 48 ± 2 d of age), housed in 4 pigs per pen with 5 pens per treatment, were assigned to 4 dietary treatments of 17, 15, and 13% CP and 13% CP plus casein for 28 d. The crystalline AA were supplemented to meet the requirement of indispensable AA in pigs. Results showed that pigs fed the 13% CP diet or the 13% CP plus casein diet had lower ( < 0.01) ADG and ADFI and a greater ( < 0.01) feed:gain ratio than pigs fed the 17% CP or 15% CP diets over the 4-wk study period. Compared with other diets, pigs fed the 13% CP diet had decreased concentrations of plasma urea nitrogen, albumin ( < 0.01), and mRNA expressions of Toll-like receptor 4 (), nuclear factor kappa B (; < 0.05), and Toll-interacting protein (; < 0.01) in the ileum and also increased activity of plasma glutamate-pyruvate transaminase ( < 0.05) and concentrations of IL-1β ( < 0.05) and tumor necrosis factor-α ( < 0.01); however, these characteristics were partly normalized by feeding the 13% CP plus casein diet. Furthermore, the plasma concentration of insulin-like growth factor 1 (IGF-1; < 0.01) and mRNA expressions of protein kinase B (), mammalian target of rapamycin (), and ribosomal protein S6 kinase () in longissimus muscle were increased ( < 0.05) in pigs fed the 13% CP plus casein diet relative to pigs fed the 17% CP or 15% CP diets. In summary, reducing dietary CP level from 17% to 15% had no effect on growth, metabolic, and immunological characteristics of 15- to 35-kg pigs. A further reduction of dietary CP level up to 13% would lead to poor growth performance, but metabolic and immunological characteristics were partly normalized using protein-bound AA to replace synthesized AA in the 13% CP diet.
authors.forename: L Q
authors.initials: LQ
authors.lastname: Che
authors.forename: X
authors.initials: X
authors.lastname: Peng
authors.forename: L
authors.initials: L
authors.lastname: Hu
authors.forename: C
authors.initials: C
authors.lastname: Wu
authors.forename: Q
authors.initials: Q
authors.lastname: Xu
authors.forename: Z F
authors.initials: ZF
authors.lastname: Fang
authors.forename: Y
authors.initials: Y
authors.lastname: Lin
authors.forename: S Y
authors.initials: SY
authors.lastname: Xu
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: B
authors.initials: B
authors.lastname: Feng
authors.forename: G
authors.initials: G
authors.lastname: Tian
authors.forename: R N
authors.initials: RN
authors.lastname: Zhang
authors.forename: H
authors.initials: H
authors.lastname: Sun
authors.forename: D
authors.initials: D
authors.lastname: Wu
authors.forename: D W
authors.initials: DW
authors.lastname: Chen
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage*; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001806:Blood Urea Nitrogen; D018753:Diet, Protein-Restricted / Q000662:veterinary*; D004044:Dietary Proteins / Q000008:administration & dosage; D019587:Dietary Supplements; D007082:Ileum / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D016328:NF-kappa B / Q000235:genetics; D012709:Serum Albumin; D013552:Swine / Q000254:growth & development / Q000276:immunology / Q000502:physiology*; D051197:Toll-Like Receptor 4 / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D016328:NF-kappa B; D012709:Serum Albumin; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D007334:Insulin-Like Growth Factor I