We investigated the effects of dietary fiber (DF) supplementation in normal or low crude protein (CP) diets on reproductive performance and nitrogen (N) utilization in primiparous gilts. In total, 77 Landrace × Yorkshire pregnant gilts were randomly allocated to four dietary treatments in a 2 × 2 factorial design. The groups comprised 1) equal intake of normal CP (12.82% and 0.61% total lysine), 2) low CP (LP) (10.53% and 0.61% total lysine), and 3) with or 4) without DF supplementation (cellulose, inulin, and pectin in a 34:10:1 ratio). A low-protein diet during gestation significantly reduced daily weight gain from days 91 to 110 of pregnancy (−162.5 g/d, P = 0.004). From N balance trials conducted at days 35 to 38, 65 to 68, and 95 to 98 of pregnancy, DF addition increased fecal N excretion at days 65 to 68 (+24.1%) and 95 to 98 (+13.8%) of pregnancy (P < 0.05) but reduced urinary N excretion (P < 0.05), resulting in greater N retention at each gestational stage. DF increased fecal microbial protein levels and excretion during gestation. An LP diet also reduced urinary N excretion at different gestational stages. An in vitro fermentation trial on culture media with nonprotein N urea and ammonium bicarbonate (NH4HCO3) as the only N sources revealed that microbiota derived from feces of gestating gilts fed the high DF diet exhibited a greater capacity to convert nonprotein N to microbial protein. Microbial fecal diversity, as measured by 16S rRNA sequencing, revealed significant changes from DF but not CP diets. Gilts fed an LP diet had a higher number of stillbirths (+0.83 per litter, P = 0.046) and a lower piglet birth weight (1.52 vs. 1.37 kg, P = 0.006), regardless of DF levels. Collectively, DF supplementation to gestation diets shifted N excretion from urine to feces in the form of microbial protein, suggesting that the microbiota had a putative role in controlling N utilization from DF. Additionally, a low-protein diet during gestation negatively affected the litter performance of gilts.

中文翻译：

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妊娠期低蛋白饮食中的膳食纤维影响初产后备母猪的氮排泄，可能受到肠道微生物群的影响

我们研究了在正常或低粗蛋白 (CP) 日粮中添加膳食纤维 (DF) 对初产后备母猪繁殖性能和氮 (N) 利用率的影响。总共有 77 头 Landrace × Yorkshire 怀孕后备母猪被随机分配到 2 × 2 因子设计中的四种饮食治疗组。这些组包括 1) 等量摄入正常 CP（12.82% 和 0.61% 总赖氨酸），2) 低 CP (LP)（10.53% 和 0.61% 总赖氨酸），和 3) 有或 4) 没有补充 DF（纤维素，菊粉和果胶的比例为 34:10:1）。妊娠期间的低蛋白饮食显着降低了妊娠第 91 天至第 110 天的每日体重增加（-162.5 g/d，P = 0.004）。在妊娠第 35 至 38 天、第 65 至 68 天和第 95 至 98 天进行的氮平衡试验中，添加 DF 增加了第 65 天至第 68 天（+24.1%）和 95 至 98 天（+13.1%）的粪便 N 排泄。8%) 的妊娠期 (P < 0.05)，但尿氮排泄减少 (P < 0.05)，导致每个妊娠期的氮潴留更多。DF 增加了妊娠期间的粪便微生物蛋白水平和排泄。LP 饮食还减少了不同妊娠阶段的尿氮排泄。在以非蛋白质 N 尿素和碳酸氢铵 (NH4HCO3) 作为唯一 N 来源的培养基上进行的体外发酵试验表明，来自饲喂高 DF 日粮的妊娠后备母猪粪便中的微生物群显示出将非蛋白质 N 转化为微生物蛋白质的更大能力。通过 16S rRNA 测序测量的微生物粪便多样性揭示了 DF 饮食而不是 CP 饮食的显着变化。饲喂 LP 日粮的后备母猪死产率较高（每窝 +0.83，P = 0.046）和较低的仔猪出生体重（1.52 对 1.37 公斤，P = 0.006），无论 DF 水平如何。总的来说，妊娠期日粮中添加 DF 将 N 以微生物蛋白的形式从尿液排泄到粪便中，这表明微生物群在控制 DF 对 N 的利用方面具有推定的作用。此外，妊娠期低蛋白饮食对后备母猪的产仔性能产生负面影响。