Department of Animal Science, South Dakota State University, Brookings, SD.
Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD.
J Anim Sci. 2020 May 1;98(5). doi: 10.1093/jas/skaa111.
A study was conducted to determine effects of reducing hindgut pH through dietary inclusion of high-amylose cornstarch (HA-starch) on growth performance, organ weights relative to live body weight (BW), blood thyroid hormone levels, and glucosinolate degradation products of nursery pigs fed cold-pressed canola cake (CPCC). A total of 240 pigs (initial BW: 7.1 kg), which had been weaned at 21 d of age, were housed in 40 pens (6 pigs per pen) and fed 4 diets (10 pens per diet) in a randomized complete block design for 28 d. Four diets were a basal diet with CPCC at 0 or 40%, and with HA-starch at 0 or 40% in a 2 × 2 factorial arrangement. The diets were fed in two phases: Phase 1 from day 0 to 14 and Phase 2 from day 14 to 28 and were formulated to have the same net energy, standardized ileal digestible AA, Ca, and standardized total tract digestible P contents. Dietary inclusion of CPCC and HA-starch was achieved by a partial or complete replacement of corn, soybean meal, and soy protein. At the end of the study, one pig from each pen was euthanized to determine organ weights, blood parameters, hindgut pH, and glucosinolate degradation products. Dietary CPCC reduced (P < 0.05) overall average daily gain (ADG) by 15%; increased (P < 0.05) relative weights of liver and thyroid gland by 27% and 64%, respectively; and reduced (P < 0.05) serum tetraiodothyronine (T4) level from 30.3 to 17.8 ng/mL. Heart, kidney, and gastrointestinal tract weights; serum triiodothyronine level; and hindgut pH of pigs were unaffected by dietary CPCC. Dietary HA-starch reduced (P < 0.05) overall ADG, relative weight of thyroid gland, cecal, and colonic pH; but increased (P < 0.05) relative weight of colon; tended to increase (P = 0.062) serum T4 level. Dietary CPCC and HA-starch interacted (P = 0.024) on relative weight of thyroid gland such that dietary CPCC increased (P < 0.05) weight of thyroid gland for HA-starch-free diet (120 vs. 197 mg/kg of BW) but not for HA-starch-containing diet (104 vs. 130 mg/kg of BW). Dietary CPCC and HA-starch interacted (P = 0.001) on cecal isothiocyanate content such that dietary CPCC increased (P < 0.05) level of isothiocyanates for HA-starch-containing diet but not for HA-starch-free diet. In conclusion, dietary CPCC reduced growth performance, increased liver, size and interfered with thyroid gland functions of pigs. However, the negative effects of dietary CPCC on thyroid gland functions of nursery pigs were alleviated by dietary HA-starch.
进行了一项研究，以确定通过饮食添加高直链淀粉玉米淀粉（HA-淀粉）来降低后肠 pH 值对生长性能、相对于活体重（BW）的器官重量、血液甲状腺激素水平和仔猪食用冷压油菜籽饼（CPCC）的硫代葡萄糖苷降解产物的影响。总共 240 头仔猪（初始 BW：7.1kg），在 21 日龄断奶后，饲养在 40 个围栏（每个围栏 6 头猪）中，并以随机完全区组设计进行了 28 天的 4 种饮食（每饮食 10 个围栏）的喂养。四种饮食是基础饮食，CPCC 添加量为 0 或 40%，HA-淀粉添加量为 0 或 40%，采用 2×2 因子排列。日粮分为两个阶段：第 0 天至第 14 天为第一阶段，第 14 天至第 28 天为第二阶段，日粮的配制具有相同的净能、标准化回肠可消化氨基酸、钙和标准化总肠道可消化磷含量。CPCC 和 HA-淀粉的饮食添加是通过部分或完全替代玉米、豆粕和大豆蛋白来实现的。在研究结束时，每个围栏的一头猪被安乐死，以确定器官重量、血液参数、后肠 pH 值和硫代葡萄糖苷降解产物。日粮 CPCC 降低了（P<0.05）仔猪的平均日增重（ADG）15%；增加了（P<0.05）肝脏和甲状腺的相对重量分别为 27%和 64%；并降低了（P<0.05）血清四碘甲状腺原氨酸（T4）水平从 30.3 至 17.8ng/mL。日粮 CPCC 对心脏、肾脏和胃肠道重量、血清三碘甲状腺原氨酸水平以及后肠 pH 值没有影响。日粮 HA-淀粉降低了（P<0.05）仔猪的平均日增重、甲状腺、盲肠和结肠 pH 值的相对重量；但增加了（P<0.05）结肠的相对重量；血清 T4 水平有升高的趋势（P=0.062）。日粮 CPCC 和 HA-淀粉在甲状腺相对重量上存在交互作用（P=0.024），即日粮 CPCC 增加了（P<0.05）无 HA-淀粉日粮的甲状腺重量（120 与 197mg/kg BW），但不增加含 HA-淀粉日粮的甲状腺重量（104 与 130mg/kg BW）。日粮 CPCC 和 HA-淀粉在盲肠异硫氰酸酯含量上存在交互作用（P=0.001），即日粮 CPCC 增加了含 HA-淀粉日粮的异硫氰酸酯水平（P<0.05），但不增加无 HA-淀粉日粮的异硫氰酸酯水平。总之，日粮 CPCC 降低了仔猪的生长性能，增加了肝脏、大小并干扰了甲状腺功能。然而，日粮 HA-淀粉减轻了日粮 CPCC 对仔猪甲状腺功能的负面影响。
