In swine production, pig movement restrictions or packing plant closures may create the need to slow growth rates of finishing pigs to ensure they remain at a marketable body weight when packing plant access is restored. Although dietary formulations can be successful at slowing pig growth, precision is needed regarding how to best formulate diets to achieve growth rate reductions. Thus, the objective was to evaluate three dietary experimental approaches aimed at slowing growth rates in finishing pigs. These approaches consisted of either increasing neutral detergent fiber (NDF), reducing essential amino acids, or reducing the dietary electrolyte balance through the addition of acidogenic salts. A total of 94 mixed-sex pigs (72.4 ± 11.2 kg BW) across two replicates were individually penned and assigned to 1 of 8 dietary treatments (n = 11–12 pigs/treatment): 1) Control diet representative of a typical corn–soybean meal-based finisher diet (CON); 2) diet containing 15% NDF from soybean hulls (15% NDF); 3) diet containing 20% NDF from soybean hulls (20% NDF); 4) diet containing 25% NDF from soybean hulls (25% NDF); 5) diet formulated as per CON but with 50% of the soybean meal replaced with corn (89% Corn); 6) diet containing 97% corn and no soybean meal or synthetic amino acids (97% Corn); 7) diet containing 2% anhydrous calcium chloride (2% CaCl2); and 8) diet containing 4% anhydrous calcium chloride (4% CaCl2). Over 28 d, pig body weights and performance were recorded weekly. At d 28, all pigs were ultrasound scanned and switched to the CON diet to evaluate compensatory gain from d 28 to 35. Overall, increased NDF did not impact any growth performance parameter (P > 0.05). Amino acid restriction reduced average daily gain (ADG), average daily feed intake (ADFI), and gain:feed (G:F) linearly (linear P < 0.001). Similarly, ADG, ADFI, and G:F were linearly reduced with increased CaCl2 inclusion (linear P < 0.001). ADG differed during the compensatory gain period (P < 0.001), with 4% CaCl2-fed pigs having a 47% increase in ADG compared with CON-fed pigs. Conversely, 15% and 25% NDF-fed pigs had reduced ADG compared with CON-fed pigs during the compensatory gain period. Gain efficiency differed from day 28 to 35 (P < 0.001), with 4% CaCl2-fed pigs having a 36% increase in G:F compared with CON-fed pigs. Altogether, these data demonstrate that both amino acid restriction and CaCl2 inclusion are effective at slowing pig growth, albeit at greater inclusion rates.

中文翻译：

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评估增加纤维、减少氨基酸或降低电解质平衡作为减缓育肥猪生长速度的日粮方法

在养猪生产中，猪的流动限制或包装厂关闭可能会导致需要减缓育肥猪的生长速度，以确保在包装厂恢复访问时它们保持在适销对路的体重。虽然日粮配方可以成功减缓猪的生长，但需要精确地确定如何最好地配方日粮以降低生长速度。因此，目的是评估三种旨在减缓育肥猪生长速度的日粮实验方法。这些方法包括增加中性洗涤剂纤维 (NDF)、减少必需氨基酸或通过添加产酸盐来降低膳食电解质平衡。共 94 头混性别猪 (72.4 ± 11. 两个重复的 2 kg BW) 分别被圈养并分配到 8 种日粮处理中的 1 种（n = 11-12 头猪/处理）： 1) 代表典型玉米-豆粕型育肥日粮 (CON) 的对照日粮；2) 含有 15% NDF 的大豆皮日粮（15% NDF）；3) 含有 20% NDF 的大豆皮日粮（20% NDF）；4) 含有 25% NDF 的大豆皮日粮（25% NDF）；5) 根据 CON 配制的日粮，但将 50% 的豆粕替换为玉米（89% 玉米）；6) 含有 97% 玉米且不含豆粕或合成氨基酸（97% 玉米）的日粮；7）含2%无水氯化钙（2% CaCl2）的日粮；8) 含有 4% 无水氯化钙 (4% CaCl2) 的饮食。超过 28 天，每周记录猪的体重和性能。在 28 天，对所有猪进行超声扫描并转为 CON 日粮，以评估 28 至 35 天的代偿性增益。总体而言，增加的 NDF 不会影响任何生长性能参数（P > 0.05）。氨基酸限制线性降低平均日增重 (ADG)、平均日采食量 (ADFI) 和增重：饲料 (G:F)（线性 P < 0.001）。类似地，ADG、ADFI 和 G:F 随着 CaCl2 含量的增加而线性降低（线性 P < 0.001）。ADG 在补偿性增重期间存在差异 (P < 0.001)，与 CON 喂养的猪相比，4% CaCl2 喂养的猪的 ADG 增加了 47%。相反，在代偿期，15% 和 25% NDF 喂养的猪与 CON 喂养的猪相比 ADG 降低。第 28 天到第 35 天的增重效率不同（P < 0.001），饲喂 4% CaCl2 的猪的 G 增加了 36%：F 与 CON 喂养的猪相比。总之，这些数据表明，氨基酸限制和 CaCl2 加入都可以有效减缓猪的生长，尽管加入率更高。