The amount of energy available for metabolism from grain-based feeds determines pig growth rate. Available energy is influenced by feed intake (FI) and the relative extent of digestion in the small intestine (SI), compared with fermentation of undigested feed in the large intestine (LI). Milled and steam-flaked sorghum and wheat were used to evaluate the following hypotheses: 1) an increase in grain digestibility increases FI, decreases the extent of large-intestinal fermentation and improves the efficiency of feed use; and 2) faecal short-chain-fatty-acids (SCFA) and pH are indicators of the extent of grain fermentation in the LI. Apparent-amylase-diffusion-coefficients (ADC) were measured in vitro as an indicator of intrinsic starch digestibility. Pigs were fed ad libitum the four grain-based diets. FI, average-daily-weight-gain (ADG), feed-conversion-ratio (FCR, FI:ADG), faecal SCFA-concentration and pH were measured weekly. Linear models were fitted between: 1) ADC and ADG, FCR, SCFA-concentration, and pH; 2) ADG and SCFA-concentration, and pH; and 3) FCR and SCFA-concentration, and pH. Grain digestibility did not affect FI, but sorghum reduced ADG (14−21 day: P < 0.05; 7−28 day: P < 0.1) and increased FCR (7−14 day: P < 0.05; 14−21day: P = 0.001) compared to wheat. Sorghum produced more faecal SCFA than wheat at 7 day & 28 day (P < 0.1), and decreased faecal pH by 0.4 (14 day, 21 day & 28 day: P < 0.001). ADG and FCR were correlated with faecal SCFA and pH (P < 0.001 to 0.05). Low intrinsic starch digestibility increased fermentation in the hind-gut, with assumed loss of energy in heat, methane and voided microbes, resulting in less energy for metabolism. Providing pigs with cereal grains of high intrinsic digestibility should increase growth rate and efficiency of feed use without increasing feed intake.

中文翻译：

---

内在谷物淀粉消化率影响结肠发酵和体重增加的粪便标志物浓度而不影响猪的采食量

谷物饲料中可用于代谢的能量决定了猪的生长速度。与大肠 (LI) 中未消化饲料的发酵相比，可用能量受采食量 (FI) 和小肠 (SI) 中消化的相对程度的影响。使用碾磨和蒸汽压片的高粱和小麦来评估以下假设：1) 谷物消化率的增加增加了 FI，降低了大肠发酵的程度并提高了饲料利用效率；2) 粪便短链脂肪酸 (SCFA) 和 pH 值是 LI 中谷物发酵程度的指标。在体外测量表观淀粉酶扩散系数 (ADC) 作为内在淀粉消化率的指标。猪随意饲喂四种以谷物为基础的饮食。FI，平均日增重（ADG），每周测量饲料转化率（FCR、FI:ADG）、粪便 SCFA 浓度和 pH 值。线性模型拟合在：1) ADC 和 ADG、FCR、SCFA 浓度和 pH 值之间；2) ADG 和 SCFA-浓度，以及 pH 值；3) FCR 和 SCFA 浓度，以及 pH。谷物消化率不影响 FI，但高粱降低 ADG（14-21 天：P < 0.05；7-28 天：P < 0.1）并增加 FCR（7-14 天：P < 0.05；14-21 天：P = 0.001 ) 与小麦相比。高粱在第 7 天和第 28 天产生的粪便 SCFA 多于小麦（P < 0.1），并使粪便 pH 值降低 0.4（第 14 天、21 天和 28 天：P < 0.001）。ADG 和 FCR 与粪便 SCFA 和 pH 值相关（P < 0.001 至 0.05）。低内在淀粉消化率增加了后肠的发酵，假定热量、甲烷和无效微生物的能量损失，导致代谢所需的能量减少。为猪提供高内在消化率的谷物应能提高生长速度和饲料利用效率，而不会增加采食量。