The lactation-pregnancy overlap in the industrialized 49-day breeding model increases nutritional demands for lactating-pregnant rabbit does. This study examined the effects of folic acid (FA) on the production performance and intestinal microflora of does with different litter size (LS, or number of kits). A total of 144 third-parity Hyplus does, aged 11 months and weighing approximately 5.00 ± 0.07 kg, were divided four treatment groups: control group (basal diet) and FA groups (basal diet + 15, 30, and 45 mg/kg FA). Does with LS of 5, 7, and 9 were slected after weaning. Our findings revealed that 1) Increased FA supplementation initially increased and then decreased the pre-lactation body weight of 21-day-old kits and prolactin (PRL) level of does, while showing an inverse trend for estrogen (E) level of does. Increased LS significantly (P < 0.05) correlated with reduced milk yield of does. There was a significant (P < 0.05) interaction between FA and LS affecting PRL, E, growth hormone (GH) levels of does, and the pre-lactation body weight of 21-day-old kits. 2) Increased FA supplementation initially increased and then decreased the post-lactation body weight of 21-day-old and 35-day-old kits, elevated plasma folic acid (PFA) level of does, and significantly (P < 0.05) impacted the pregnancy rate of does. Increased LS was associated with reduced post-lactation body weight in 21-day-old and 35-day-old kits (P < 0.05). There was a significant (P < 0.05) interaction between FA and LS affecting plasma insulin-like growth factor-1 (IGF-1), homocysteine (HCY), PFA levels of does, post-lactation body weight of 21-day-old kits, and weaning body weight of 35-day-old kits. 3) FA supplementation promoted the growth of Ruminococcaceae and Rikenella_RC9_gut_group in feces of does, indicating enhanced anti-inflammatory capabilities and crude fiber (CF) breakdown. In summary, FA supplementation improved conception rates, regulated lactation-related hormone synthesis and secretion, increased body weight of 21-day-old kits, and enhanced intestinal anti-inflammatory functions.

中文翻译：

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探索不同产仔数的哺乳期怀孕兔的最佳叶酸补充水平


工业化 49 天育种模型中的哺乳-怀孕重叠增加了哺乳期怀孕兔子的营养需求。本研究检查了叶酸 （FA） 对不同窝产出量 （LS 或试剂盒数量） 的生产性能和肠道菌群的影响。共有 144 只三胎 Hyplus 鸻，年龄 11 个月，体重约 5.00 ± 0.07 kg，分为四个治疗组：对照组（基础饮食）和 FA 组（基础饮食 + 15、30 和 45 mg/kg FA）。断奶后选择 LS 为 5、7 和 9 的 Do。我们的研究结果显示，1） 增加的 FA 补充剂最初增加了 21 天龄试剂盒的泌乳前体重和催乳素 （PRL） 水平，同时显示出雌激素 （E） 水平的相反趋势。LS 显著增加 （P < 0.05） 与 do 产奶量降低相关。FA 和 LS 之间存在显着 （P < 0.05） 相互作用，影响 PRL 、 E 、 do 的生长激素 （GH） 水平和 21 日龄幼崽的哺乳前体重。2） 增加 FA 补充剂最初增加，然后降低 21 日龄和 35 日龄幼崽的哺乳后体重，血浆叶酸 （PFA） 水平升高，并显着 （P < 0.05） 影响 do 的妊娠率。在 21 日龄和 35 日龄试剂盒中，LS 增加与哺乳后体重减轻有关 （P < 0.05）。FA 和 LS 之间存在显着 （P < 0.05） 相互作用，影响血浆胰岛素样生长因子-1 （IGF-1）、同型半胱氨酸 （HCY）、DOS 的 PFA 水平、21 日龄幼猪的哺乳后体重和 35 日龄幼猪的断奶体重。 3） 添加 FA 促进了瘤胃球菌科的生长和粪便中 Rikenella_RC9_gut_group，表明抗炎能力和粗纤维 （CF） 分解增强。总之，补充 FA 提高了受孕率，调节了与哺乳相关的激素合成和分泌，增加了 21 日龄试剂盒的体重，并增强了肠道抗炎功能。