Department of Animal Sciences and Industry, College of Agriculture, Manhattan, KS, USA.
Department of Statistics, College of Arts and Sciences, Manhattan, KS, USA.
J Anim Sci. 2021 May 1;99(5). doi: 10.1093/jas/skab090.
Two experiments were conducted to determine the effects of crude protein (CP) level in diets containing coarse wheat bran (CWB) with or without pharmacological levels of Zn (provided by zinc oxide: ZnO) on growth performance and fecal DM of nursery pigs. In experiment 1, 360 barrows (Line 200 × 400, DNA, Columbus, NE, initially 5.6 kg) were allotted to 1 of 6 dietary treatments from d 0 to 21 after weaning with 5 pigs per pen and 12 pens per treatment. Treatments included a positive control diet (21% CP) with 3,000 mg/kg Zn in phase 1 and 2,000 mg/kg in phase 2; negative control (21% CP) with 110 mg/kg added Zn, and 4 diets containing 4% CWB and 110 mg/kg added Zn formulated to contain 21%, 19.5%, 18%, or 16.5% CP. The 2 control diets and 21% CP CWB diet contained 1.40% standardized ileal digestible (SID) Lys in phase 1 and 1.35% SID Lys in phase 2, while the 19.5%, 18%, and 16.5% CP diets contained 1.33, 1.25 and 1.20% Lys, respectively, in both phases. Pigs fed the positive control diet containing pharmacological ZnO had increased (P < 0.05) ADG and G:F compared with the negative control and the 21% CP CWB diet. Reducing CP (concurrently with SID Lys) in diets containing CWB decreased ADG and G:F (linear, P = 0.002); however, fecal DM increased (linear, P = 0.005). In experiment 2, two groups of 300 and 350 pigs, initially 7.0 and 6.2 kg, respectively, were used with 5 pigs per pen and 26 pens per treatment. The objective was to determine if adding back essential AA would improve growth performance of pigs fed the low CP diets. All dietary treatments were fed for 13 days, contained 4% CWB, and consisted of: (1) positive control with 2,000 mg/kg of Zn and 21% CP (1.35% SID Lys); (2) no ZnO and 21% CP; and 3 diets with no ZnO formulated to 18% CP and (3) 1.2% SID Lys; (4) 1.35% SID Lys by the addition of feed grade amino acids (AA), and (5) diet 4 with non-essential amino acids (NEAA; Gly and Glu). Pigs fed 21% CP with ZnO had increased (P = 0.001) ADG compared to those fed 18% CP (1.35% SID Lys) with high levels of feed grade amino acids or those fed the reduced SID Lys (1.2%) diet. Overall, G:F was improved (P < 0.001) for pigs fed 21% CP diets and those fed the 18% CP diet with NEAA compared to pigs fed 1.2% SID Lys and pigs fed high levels of feed grade amino acids. Fecal DM was increased for pigs fed the reduced SID Lys diet. In summary, pharmacological levels of Zn improve pig growth performance, but reducing CP (and subsequently SID Lys) decreased nursery pig growth performance.
进行了两项实验，以确定日粮中粗小麦麸（CWB）和药理学水平锌（由氧化锌提供：ZnO）对生长性能和仔猪粪便 DM 的影响。在实验 1 中，360 头公猪（Line 200 × 400，DNA，哥伦布，NE，初始体重为 5.6kg）从断奶后 0 天到 21 天被分配到 6 种日粮处理中的 1 种，每个栏 5 头猪，每个处理 12 个栏。处理包括 1 种阳性对照日粮（21%CP），第 1 阶段含有 3000mg/kg Zn，第 2 阶段含有 2000mg/kg Zn；1 种阴性对照（21%CP），添加 110mg/kg Zn，和 4 种含有 4%CWB 和 110mg/kg 添加 Zn 的日粮，配方分别含有 21%、19.5%、18%或 16.5%CP。2 种对照日粮和 21%CP CWB 日粮在第 1 阶段含有 1.40%标准回肠可消化（SID）赖氨酸，在第 2 阶段含有 1.35% SID 赖氨酸，而 19.5%、18%和 16.5%CP 日粮在两个阶段分别含有 1.33%、1.25%和 1.20%赖氨酸。与阴性对照和 21%CP CWB 日粮相比，饲喂含药理学 ZnO 的阳性对照日粮的猪 ADG 和 G:F 增加（P<0.05）。日粮中降低 CP（同时降低 SID 赖氨酸）降低了 ADG 和 G:F（线性，P=0.002）；然而，粪便 DM 增加（线性，P=0.005）。在实验 2 中，使用两组 300 头和 350 头猪，初始体重分别为 7.0kg 和 6.2kg，每栏 5 头猪，每个处理 26 个栏。目的是确定添加必需氨基酸是否会改善饲喂低 CP 日粮的猪的生长性能。所有日粮处理均饲喂 13 天，含有 4%CWB，由以下几种组成：（1）含 2000mg/kg Zn 和 21%CP（1.35% SID 赖氨酸）的阳性对照；（2）不含 ZnO 和 21%CP；和 3 种不含 ZnO 的日粮，配方分别为 18%CP 和（3）1.2% SID 赖氨酸；（4）通过添加饲料级氨基酸（AA）获得 1.35% SID 赖氨酸；和（5）日粮 4 用非必需氨基酸（NEAA；甘氨酸和谷氨酸）。与饲喂 18%CP（1.35% SID 赖氨酸）和高饲料级氨基酸或饲喂低 SID 赖氨酸（1.2%）日粮的猪相比，饲喂 21%CP 加 ZnO 的猪 ADG 增加（P=0.001）。总体而言，与饲喂 1.2% SID 赖氨酸和饲喂高饲料级氨基酸的猪相比，饲喂 21%CP 日粮和饲喂含 NEAA 的 18%CP 日粮的猪的 G:F 得到改善（P<0.001）。饲喂低 SID 赖氨酸日粮的猪粪便 DM 增加。总之，药理学水平的 Zn 提高了猪的生长性能，但降低 CP（随后降低 SID 赖氨酸）降低了仔猪的生长性能。
