Miller Kayla A, Spencer Joel D, Mendoza Omarh F, Krishnan Hari B, Nisley Mitchell J, Gabler Nicholas K
Department of Animal Science, Iowa State University, Ames, IA, USA50011.
United Animal Health, Sheridan, IN, USA46069.
J Anim Sci. 2025 Jan 4;103. doi: 10.1093/jas/skaf256.
Soybeans contain trypsin inhibitor proteins that are antinutritional and may result in growth performance inhibition through reduced amino acid bioavailability. The objective of this experiment was to determine the level of active trypsin inhibitor units (TIU) per milligram (TIU/mg) of complete feed that leads to reductions in growth performance and nitrogen digestibility. Forty-five grower gilts (39.7 ± 2.1 kg BW) were individually penned and fed 1 of the 5 dietary treatments (n = 9 pigs/trt) in a completely randomized design for the duration of this 27-d experiment. Diets were fed in meal form and formulated utilizing raw ground soybeans and soybean meal to achieve increasing levels of TIU/mg of complete feed of 0.89, 1.77, 3.55, 6.99, and 11.54 TIU/mg. Analyzed complete diets contained 0.99, 2.23, 3.07, 6.49, and 9.38 TIU/mg. Diets were balanced to the same grams of standardized ileal digestible (SID) lysine and SID lysine per megacalorie of metabolizable energy of 2.85 and neutral detergent fiber (NDF) concentration of 7.4% utilizing crystalline amino acids, soybean oil, and soybean hulls, respectively. Pig body weight (BW) and individual feed intake were collected on days 0, 21, and 27 to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F). On day 21 of the experiment, pigs were placed into metabolism stalls for 6 d to determine nitrogen balance and apparent total tract digestibility (ATTD) of nitrogen. All data were analyzed with pig as the experimental unit and TIU/mg level as a fixed effect by ANOVA, including linear and quadratic effect contrasts. Average daily gain decreased as dietary concentrations TIU/mg increased (1.07, 1.03, 1.02, 0.91, and 0.83 kg/d, respectively, linear P < 0.001). No differences in ADFI (P > 0.10) were detected, but G:F decreased (0.48, 0.45, 0.43, 0.41, 0.36, respectively, linear P < 0.001) was observed as TIU/mg increased from 0.99 to 9.38 TIU/mg. Final BW of pigs fed 9.38 TIU/mg was reduced by 9.32% compared with 0.99 TIU/mg (62.3 vs. 68.7 kg, linear P < 0.001). Nitrogen ATTD decreased when pigs were fed 9.38 TIU/mg compared to 0.99 and 2.23 TIU/mg fed pigs (83.26% vs. 90.29% and 89.57%, respectively, P < 0.001). In conclusion, as TIU from soybeans increased in grower pig diets, linear reductions in protein digestibility, growth rates, and feed efficiency were observed.
大豆含有抗营养的胰蛋白酶抑制剂蛋白，可能会通过降低氨基酸的生物利用率而抑制生长性能。本实验的目的是确定每毫克全价饲料中活性胰蛋白酶抑制剂单位（TIU）的水平，该水平会导致生长性能和氮消化率降低。45头生长阶段的后备母猪（体重39.7±2.1千克）被单独关在栏中，在这个为期27天的实验期间，按照完全随机设计，饲喂5种日粮处理中的1种（每组n = 9头猪）。日粮以粉料形式饲喂，使用生大豆粉和豆粕进行配制，以使全价饲料中TIU/毫克的水平分别达到0.89、1.77、3.55、6.99和11.54 TIU/毫克。分析后的全价日粮含有0.99、2.23、3.07、6.49和9.38 TIU/毫克。日粮通过添加晶体氨基酸、大豆油和大豆皮，将每兆卡代谢能的标准化回肠可消化（SID）赖氨酸和SID赖氨酸的克数平衡至相同的2.85，中性洗涤纤维（NDF）浓度平衡至7.4%。在第0、21和27天收集猪的体重（BW）和个体采食量，以计算平均日增重（ADG）、平均日采食量（ADFI）和饲料效率（G:F）。在实验的第21天，将猪放入代谢笼中6天，以确定氮平衡和氮的表观全肠道消化率（ATTD）。所有数据以猪作为实验单位，TIU/毫克水平作为固定效应，通过方差分析进行分析，包括线性和二次效应对比。随着日粮中TIU/毫克浓度的增加，平均日增重下降（分别为1.07、1.03、1.02、0.91和0.83千克/天，线性P < 0.001）。未检测到ADFI的差异（P > 0.10），但随着TIU/毫克从0.99增加到9.38 TIU/毫克，G:F下降（分别为0.48、0.45、0.43、0.41、0.36，线性P < 0.001）。与0.99 TIU/毫克相比，饲喂9.38 TIU/毫克的猪的末重降低了9.32%（62.3对68.7千克，线性P < 0.001）。与饲喂0.99和2.23 TIU/毫克的猪相比，饲喂9.38 TIU/毫克的猪的氮ATTD降低（分别为83.26%对90.29%和89.57%，P < 0.001）。总之，随着生长猪日粮中大豆TIU的增加，观察到蛋白质消化率、生长速度和饲料效率呈线性下降。
