The objective of the present experiment was to determine the minimum adaptation period for total tract digestibility experiments in gestating and lactating sows using the indigestible index method. Five gestating and 5 lactating sows at parities 3 to 5 were used. An indigestible index of 0.5% chromic oxide was supplemented to a diet based on corn and soybean meal. The daily feed allowance for gestating sows was 2 kg and 2 equal meals were provided to the sows. Lactating sows were fed 6 kg of feed per day in 3 equal meals. After feeding a diet without supplemental chromic oxide for 5 days, index-supplemented diets were provided to the gestating and lactating sows. Feces were collected at 24-h intervals for 9 and 7 days from gestating and lactating sows, respectively. Fecal Cr concentrations increased linearly (P < 0.001) and quadratically (P < 0.001) with collection time in both gestating and lactating sows. Minimum adaptation periods were estimated by one-slope broken-line model. The break point of Cr concentrations in feces was day 7.2 (SE = 0.3) in the gestating sows and day 4.2 (SE = 0.2) in the lactating sows, respectively. Apparent total tract digestibility of dry matter, organic matter, and energy on day 4 was less (P < 0.001) than that on day 8 to 9 in gestating sows fed the experimental diet with a 2-kg feed allowance. In lactating sows fed the experimental diets with a 6-kg feed allowance, the apparent total tract digestibility of dry matter, organic matter, and energy on day 3 was less (P < 0.05) than that on day 5 to 7. In conclusion, at least 8 days of adaptation period are required for gestating sows to determine total tract digestibility using Cr as the indigestible index method whereas 5 days of adaptation period are required for gestating sows. An insufficient adaptation period results in lower digestibility values.

中文翻译：

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在使用指数法进行总消化率评估时，与哺乳期母猪相比，饲料供给量受限的妊娠母猪在收集粪便前需要更长的适应期


本试验的目的是使用不可消化指数法确定妊娠和哺乳母猪总消化率实验的最小适应期。使用了 5 头妊娠母猪和 5 头哺乳母猪，胎次为 3 至 5。在以玉米和豆粕为基础的饮食中补充了 0.5% 的易消化指数氧化铬。妊娠母猪的每日饲料供给量为 2 公斤，并为母猪提供 2 份相等的膳食。哺乳母猪每天喂食 6 公斤饲料，分 3 次等餐。在饲喂不补充氧化铬的日粮 5 天后，向妊娠和哺乳母猪提供补充指数的日粮。分别以 24 小时的间隔从妊娠母猪和哺乳母猪收集粪便 9 天和 7 天。妊娠和哺乳母猪粪便 Cr 浓度随收集时间线性增加 （P < 0.001） 和二次方 （P < 0.001）。通过单斜率虚线模型估计最小适应期。妊娠母猪粪便中 Cr 浓度的转折点分别为第 7.2 天 （SE = 0.3） 和哺乳母猪第 4.2 天 （SE = 0.2）。饲喂 2 kg 饲料供给量的试验日粮的妊娠母猪，第 4 天干物质、有机质和能量的表观总消化率低于第 8 至 9 天（P < 0.001）。在饲喂饲料供给量为 6 kg 的试验日粮的泌乳母猪中，第 3 天干物质、有机质和能量的表观总消化率低于第 5 至 7 天（P < 0.05）。总之，使用 Cr 作为难消化指数法，妊娠母猪需要至少 8 天的适应期来确定总消化率，而妊娠母猪需要 5 天的适应期。 适应期不足会导致消化率值降低。