Effects of added fat in sow diets on the sows’ reproductive performance and offspring growth performance are influenced by multiple factors such as genetics, nutrition, parity, ambient temperatures, and farm management. Individual studies cannot cover all these factors. With the view to address this challenge, we searched all studies that were published from 1986 to 2020, and performed a systematic review and meta-analysis on the fat effect. In total, 19 papers were collected and analyzed. Fat supplementation in sow diets during late gestation and lactation decreased average daily feed intake (ADFI, P < 0.05) and tended to increase average daily energy intake (ADEI, P = 0.11). It had no impact on litter weights at birth (P = 0.40) or weaning (P = 0.46). It increased total numbers of piglets at birth (P = 0.07), but had no effect on liveborn per litter (P = 0.90) or survival rate (P = 0.48) of piglets to weaning. Fat supplementation had no significant effect on sow body weight loss (P = 0.67) or backfat thickness changes (P = 0.66), but sows fed diets with added fat had increased milk fat concentration (P = 0.03) and shorter wean to estrus intervals (WEI, P = 0.01). In specific circumstances, fat supplementation tended to improve growth performance of piglets with low litter weights at birth (P = 0.14), or when the sows lost large amounts of body weight during lactation (P = 0.11). The level of supplemented fat was 10% and higher would decrease liveborn per litter at neutral temperature (P = 0.10). The meta-analysis revealed that fat supplementation to sows diet during late gestation and lactation can be beneficial for sow reproductive performance and litter growth performance.

中文翻译：

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日粮脂肪对母猪繁殖性能和仔猪生长性能影响的系统评价和荟萃分析

母猪日粮中添加脂肪对母猪繁殖性能和后代生长性能的影响受到多种因素的影响，例如遗传、营养、胎次、环境温度和农场管理。个别研究无法涵盖所有​​这些因素。为了应对这一挑战，我们检索了 1986 年至 2020 年发表的所有研究，并对脂肪效应进行了系统评价和荟萃分析。共收集和分析了 19 篇论文。在妊娠后期和哺乳期母猪日粮中添加脂肪会降低平均每日采食量（ADFI，P < 0.05），并倾向于增加平均每日能量摄入（ADEI，P = 0.11）。它对出生时的窝重（P = 0.40）或断奶（P = 0.46）没有影响。它增加了出生时的仔猪总数（P = 0.07），但对断奶仔猪的每窝活产 (P = 0.90) 或存活率 (P = 0.48) 没有影响。脂肪补充对母猪体重减轻（P = 0.67）或背膘厚度变化（P = 0.66）没有显着影响，但饲喂添加脂肪日粮的母猪增加了乳脂浓度（P = 0.03）并缩短了断奶至发情的间隔（P = 0.03）。魏，P = 0.01）。在特定情况下，脂肪补充倾向于改善出生时窝重低的仔猪的生长性能（P = 0.14），或当母猪在哺乳期间失去大量体重时（P = 0.11）。在中性温度下，添加脂肪的水平为 10% 和更高会减少每窝的活产 (P = 0.10)。