Renema R A, Robinson F E, Proudman J A, Newcombe M, McKay R I
Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Canada.
Poult Sci. 1999 May;78(5):629-39. doi: 10.1093/ps/78.5.629.
The effects of broiler breeder BW and nutrient intake on ovary morphology and plasma reproductive hormone profiles were examined at photostimulation (PS) (21 wk) and at sexual maturity (SM) in standard (STD) and low (LOW), or high (HIGH) BW birds provided either restricted (RF) or ad libitum (AL) access to feed between PS and SM. At PS, 30 Shaver Starbro pullets at target BW were assigned to the STD treatment, and birds either 20% heavier (HIGH) or lighter (LOW) assigned accordingly. Ten birds of each size group were processed immediately for carcass analysis and 10 birds assigned to each size by feed interaction group. Blood samples were taken at 3-d intervals beginning at PS and profiles constructed for estradiol-17beta, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) to examine the relationship between body size, feeding level, and reproduction. Birds were processed for assessment of reproductive traits following SM. The AL birds reached SM with 11.0 large yellow follicles (LYF) (> 10 mm diameter) compared to 7.1 in RF birds. Small follicle atresia (< 5 mm diameter) was low in AL birds (10.3) compared to RF birds (32.3). The extent of small follicle atresia in RF birds was found to be inversely proportional to LYF number by stepwise regression. Increased small follicle atresia was associated with a longer sexual maturation period in RF birds (r = 0.619; P = 0.0003). Plasma estradiol-17beta concentration was greater in HIGH than in STD or LOW birds at PS, suggesting more advanced ovary development in HIGH birds. Estradiol-17beta profiles were similar in shape in all treatments, with the primary difference being the length of time prior to a substantial estradiol-17beta increase. Following PS, plasma LH and FSH concentrations of AL birds increased to levels nearly double that of RF birds, indicating a role for nutrient intake with rate of reproductive development. Plasma LH and FSH concentrations remained elevated for a greater time period in RF birds, however, possibly relating to the development of processes limiting LYF recruitment. This experiment demonstrated a modulation of reproductive hormone concentrations during sexual maturation by feeding level in conjunction with a sensitivity of the ovary to nutritional effects.
在光照刺激（PS）（21周龄）和性成熟（SM）时，对标准体重（STD）、低体重（LOW）或高体重（HIGH）的肉种鸡，在PS和SM之间给予限饲（RF）或自由采食（AL），研究其体重和营养摄入量对卵巢形态和血浆生殖激素水平的影响。在PS时，将30只达到目标体重的沙维星布罗小母鸡分配到STD处理组，并相应地分配体重比目标体重重20%（HIGH）或轻20%（LOW）的鸡。每个体重组的10只鸡立即进行屠体分析，每个体重组按采食方式再分为两个亚组，每组10只鸡。从PS开始每隔3天采集血样，测定雌二醇-17β、促黄体生成素（LH）和促卵泡生成素（FSH）水平，以研究体重、采食水平与繁殖性能之间的关系。在SM后对鸡进行繁殖性状评估。AL组鸡达到SM时平均有11.0个大黄卵泡（LYF）（直径>10 mm），而RF组为7.1个。AL组鸡小卵泡闭锁（直径<5 mm）发生率（10.3）低于RF组（32.3）。通过逐步回归分析发现，RF组鸡小卵泡闭锁程度与LYF数量呈负相关。RF组鸡小卵泡闭锁增加与性成熟时间延长有关（r = 0.619；P = 0.0003）。在PS时，HIGH组鸡血浆雌二醇-17β浓度高于STD组或LOW组，表明HIGH组鸡卵巢发育更成熟。所有处理组雌二醇-17β水平变化曲线形状相似，主要差异在于雌二醇-17β大幅升高前的时间长度。PS后，AL组鸡血浆LH和FSH浓度增加至RF组鸡的近两倍，表明营养摄入量对生殖发育速度有影响。然而，RF组鸡血浆LH和FSH浓度在较长时间内保持较高水平，这可能与限制LYF募集的过程有关。本实验表明，采食水平可调节性成熟期间生殖激素浓度，且卵巢对营养效应敏感。
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