Yang H, Foxcroft G R, Pettigrew J E, Johnston L J, Shurson G C, Costa A N, Zak L J
University of Minnesota, St. Paul, USA.
J Anim Sci. 2000 Apr;78(4):993-1000. doi: 10.2527/2000.784993x.
Primiparous sows (n = 36) were used to evaluate the effects of dietary lysine intake in lactation on follicular development and oocyte maturation after weaning. Sows were assigned randomly to one of three diets containing .4% (low lysine, LL), 1.0% (medium lysine, ML), or 1.6% (high lysine, HL) total lysine. All diets contained 2.1 Mcal NE/kg and exceeded NRC (1988) requirements for all other nutrients. Actual lysine intakes over an 18-d lactation were 16, 36, and 56 g/d for sows consuming LL, ML, and HL, respectively. Ovarian data were analyzed for sows determined to have been slaughtered during the first proestrus period after weaning, using previously established criteria. Compared with sows fed ML and HL, sows fed LL tended to have lower uterine weight, follicular fluid volume, and follicular fluid (FF) estradiol (E2) content (P < .15), but similar ovarian weight and follicular fluid IGF-I concentration. Within the largest 15 preovulatory follicles, sows fed LL had a lower percentage of large (> or = 7.0 mm) follicles (33 vs 50 and 58%; P < .01) and a higher percentage of medium (5.5 to 7.0 mm) follicles (62 vs 44 and 39%; P < .01) but a similar percentage of small (< or = 5.5 mm) follicles (4.4 vs 5.9 and 3.7%; P > .15), respectively, compared with sows fed ML or HL. Standardized pools of oocytes aspirated from follicles of prepubertal gilts were incubated for 44 h with pooled FF recovered from the largest 15 follicles of each experimental sow. Fewer oocyte nuclei matured to metaphase II of meiosis when cultured with FF recovered from sows fed LL, than from sows fed ML or HL (47.1 vs 59.8 and 63.8%, respectively; P < .01). Our results suggest that low lysine (protein) intake in primiparous lactating sows impaired follicular development and reduced the ability of follicles to support oocyte maturation. However, high compared with medium lysine (protein) intake had no further positive effects on ovarian function.
选用初产母猪（n = 36）来评估泌乳期日粮赖氨酸摄入量对断奶后卵泡发育和卵母细胞成熟的影响。母猪被随机分配到三种日粮中的一种，日粮总赖氨酸含量分别为0.4%（低赖氨酸，LL）、1.0%（中赖氨酸，ML）或1.6%（高赖氨酸，HL）。所有日粮的净能均为2.1Mcal/kg，且其他所有营养素均超过NRC（1988）的要求。在18天的泌乳期内，采食LL、ML和HL日粮的母猪实际赖氨酸摄入量分别为16、36和56g/d。根据先前制定的标准，对断奶后第一个发情前期被判定屠宰的母猪的卵巢数据进行分析。与采食ML和HL日粮的母猪相比，采食LL日粮的母猪子宫重量、卵泡液体积和卵泡液（FF）雌二醇（E2）含量往往较低（P < 0.15），但卵巢重量和卵泡液IGF-I浓度相似。在最大的15个排卵前卵泡中，采食LL日粮的母猪大卵泡（≥7.0mm）的比例较低（33% vs 50%和58%；P < 0.01），中卵泡（5.5至7.0mm）的比例较高（62% vs 44%和39%；P < 0.01），但小卵泡（≤5.5mm）的比例相似（4.4% vs 5.9%和3.7%；P > 0.15），与采食ML或HL日粮的母猪相比。从青春期前后备母猪的卵泡中吸出的标准化卵母细胞池，与从每头实验母猪最大的15个卵泡中回收的混合FF一起孵育44小时。与用采食ML或HL日粮的母猪回收的FF培养时相比，用采食LL日粮的母猪回收的FF培养时，成熟到减数分裂中期II的卵母细胞核较少（分别为47.1% vs 59.8%和63.8%；P < 0.01）。我们的结果表明，初产泌乳母猪低赖氨酸（蛋白质）摄入量会损害卵泡发育，并降低卵泡支持卵母细胞成熟的能力。然而，与中赖氨酸（蛋白质）摄入量相比，高摄入量对卵巢功能没有进一步的积极影响。
