Reduced protein diet manifested potential to mitigate heat production based on the concept of ideal amino acid profile. The hypothesis of this study was that lactating sows fed a low crude protein (LCP) diet with supplemental amino acid produce less heat compared to those fed a high crude protein (HCP) diet under both thermal neutral (TN) and heat stress (HS) conditions. Thirty-two lactating sows were allotted to HCP (193 g CP/kg) and LCP (140 g CP/kg) diets under thermal neutral (TN, 21 ± 1.5 °C) or cycling heat stress (HS, 32 ± 1.5 °C daytime and 24 ± 1.5 °C nighttime) conditions. Diets contained 0.90% SID lysine and 10.8 MJ/kg net energy. Positive pressure indirect calorimeters were used to measure gas exchange in individual sows with litters, and individual piglets on days 4, 8, 14 and 18. Sow and litter weights were recorded on days 1, 10 and 21. Sow total heat production (THP) was calculated by subtracting litter THP from sow + litter THP based on BW0.75. Sow BW and body protein (BP) loss was greater for LCP diet compared to HCP diet in peak lactation (P < 0.05 and P < 0.01, respectively) and throughout the entire lactation period (P < 0.05 and P = 0.056, respectively) under HS conditions. Heat-stressed sows fed HCP diet had higher (P < 0.05) rectal temperature at 13:00 (P < 0.05) and 19:00 (P < 0.01), and higher respiration rate at 07:00 (P < 0.05), 13:00 (P < 0.05) and 19:00 (P < 0.05) compared to TN sows fed HCP diet. In sows fed LCP diet, those under HS tended to have higher (P = 0.098) rectal temperature at 13:00 and had higher (P < 0.05) respiration rate at 07:00, 13:00 and 19:00 compared to TN sows. The relationship between daily THP and days in lactation of sows fed LCP diet was quadratic (P < 0.05), with an ascending trend until day 14 and a descending trend from days 14 to 18. Sows fed LCP diet had lower daily THP at day 18 (P < 0.001) compared to those fed the HCP diet under HS conditions. Reduction in THP in sows fed LCP diet was largely associated with THP on day 18 of lactation under HS conditions. Feeding LCP diets alleviated the increased body temperature in sows under HS conditions throughout lactation, which was accompanied by a reduction in respiration rate. Total heat production is associated with days in lactation, in particular under HS conditions with THP appearing to peak between days 14 and 18.

中文翻译：

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接近理想氨基酸分布的日粮对暴露于热中性和热应激条件下的哺乳母猪产热的影响。


基于理想氨基酸谱的概念，减少蛋白质饮食显示出减少热量产生的潜力。本研究的假设是，在热中性（TN）和热应激（HS）条件下，与饲喂高粗蛋白（HCP）日粮的哺乳母猪相比，饲喂添加氨基酸的低粗蛋白（LCP）日粮的哺乳母猪产生的热量更少状况。 32 头泌乳母猪在中性热应激 (TN, 21 ± 1.5 °C) 或循环热应激 (HS, 32 ± 1.5 °C) 下分配 HCP (193 g CP/kg) 和 LCP (140 g CP/kg) 日粮白天和 24 ± 1.5 °C 夜间）条件。饮食中含有 0.90% SID 赖氨酸和 10.8 MJ/kg 净能量。使用正压间接热量计测量第 4、8、14 和 18 天的每窝母猪和仔猪的气体交换。在第 1、10 和 21 天记录母猪和窝体重。 母猪总产热量 (THP)计算方法是根据 BW0.75 从母猪 + 窝 THP 中减去窝 THP。与 HCP 日粮相比，LCP 日粮在泌乳高峰期（分别为 P < 0.05 和 P < 0.01）和整个泌乳期（分别为 P < 0.05 和 P = 0.056）的母猪体重和身体蛋白质 (BP) 损失更大。 HS 条件。饲喂 HCP 日粮的热应激母猪在 13:00 (P < 0.05) 和 19:00 (P < 0.01) 时直肠温度较高 (P < 0.05)，并且在 07:00 (P < 0.05) 时呼吸频率较高，13 :00 (P < 0.05) 和 19:00 (P < 0.05) 与饲喂 HCP 日粮的 TN 母猪相比。在饲喂 LCP 日粮的母猪中，与 TN 母猪相比，HS 母猪在 13:00 时的直肠温度往往较高 (P = 0.098)，并且在 07:00、13:00 和 19:00 时的呼吸频率较高 (P < 0.05)。 。饲喂 LCP 日粮的母猪的每日 THP 与泌乳天数之间呈二次关系（P < 0.05)，直到第 14 天呈上升趋势，从第 14 天到第 18 天呈下降趋势。与在 HS 条件下饲喂 HCP 日粮的母猪相比，饲喂 LCP 日粮的母猪在第 18 天的每日 THP 较低 (P < 0.001)。饲喂 LCP 日粮的母猪 THP 降低主要与 HS 条件下泌乳第 18 天的 THP 相关。在整个哺乳期，饲喂 LCP 日粮可缓解 HS 条件下母猪体温升高的情况，同时伴随着呼吸频率的降低。总产热量与哺乳期天数有关，特别是在 HS 条件下，THP 在第 14 至 18 天之间达到峰值。