青春期日粮蛋白质水平和限饲对后备母猪乳腺发育的影响（原创）

畜牧编辑

　　The possible roles of dietary protein level and feed restriction in regulating mammary development of prepubertal gilts were investigated.

　　本试验的研究目的是评估后备母猪青春期日粮蛋白质水平及限饲对母猪乳腺发育的影响。

　　Crossbred gilts were fed a commercial diet until 90 d of age and then divided into four nutritional regimens based on two pelleted diets (as-fed basis): a high-protein diet (HP = 13.8 MJ of ME, 1.0% total lysine, 18.7% CP) and a low-protein diet (LP = 13.8 MJ of ME, 0.7% total lysine, 14.4% CP).

　　90日龄杂交母猪。两种颗粒料分别为：高蛋白日粮（ME13.8MJ/kg，总赖氨酸1.0%，CP18.7%）；低蛋白日粮（ME13.8MJ/kg，总赖氨酸0.7%，CP14.4%）。

　　Nutritional regimens were as follows:1) HP ad libitum until slaughter (n = 22, T1); 2)HP ad libitum until 150 d of age followed by LP untilslaughter (n = 20, T2); 3) LP ad libitum until slaughter(n = 21, T3); and 4) HP with a 20% feed restriction untilslaughter (n = 19, T4).

　　4种处理分别为：自由采食高蛋白日粮至屠宰（n=22，T1）；自由采食高蛋白日粮至150日龄，后自由采食低蛋白日粮至屠宰（n=20，T2）；自由采食低蛋白日粮至屠宰（n=21，T3）；20%限饲高蛋白日粮至屠宰（n=19，T4）。

　　Gilts were weighed, their backfat thickness was measured, and jugular blood samples were obtained on d 90, 150, and at slaughter to determine concentrations of prolactin, IGF-I, leptin, and glucose. Gilts were slaughtered 8 ± 1 d after their first or second estrus (202.7 ± 14.5 d of age). Mammary glands were excised, parenchymal and extraparenchymal tissues were dissected, and composition of parenchymal tissue (protein, fat, DM, DNA, protein/DNA) was determined.

　　试验母猪于第1次或第2次发情后的8±1天（202.7 ± 14.5日龄）屠宰。记录母猪第90日龄、150日龄、屠宰时的体重、背膘厚，并同时收集颈静脉血液用于检测其中激素水平。屠宰时切割乳腺组织，分析乳腺外周、实质组织中蛋白质、脂肪、干物质、DNA、蛋白质/DNA。

　　The T4 gilts weighed less (P < 0.01) and had less backfat (P < 0.01) than did gilts on other treatments on d 150 and at slaughter.

　　T4组母猪150日龄、屠宰时体重、背膘厚显著低于其它3组。

　　Treatments had no significant effects on prolactin, IGF-I, or glucose concentrations, but there was a treatment × day interaction (P< 0.01) for leptin, with concentrations being lower at slaughter in restricted-fed (T4) vs. LP (T3) gilts (P <0.05).

　　各组母猪屠宰时血液催乳素、IGF-I、葡萄糖浓度均无显著差异，但T4组母猪血液leptin水平显著低于T3组。

　　There was less extraparenchymal mammary tissue (P < 0.01) in T4 gilts than in gilts from the other groups and a tendency (P = 0.13) for the amount of parenchymal tissue to be lower in T4 gilts.

　　T4组母猪乳腺外周组织重量显著低于其它3组，导致乳腺实质组织重量也低于其它3组，但差异不显著。

　　In conclusion,a lower lysine intake during prepuberty did not hinder mammary development of gilts, but a 20% feed restriction decreased mass of parenchymal and extraparenchymaltissues. The effect of feed restriction on extraparenchymal tissue is most likely associated with the lower fat deposition.

　　总结：后备母猪青春期饲喂低蛋白日粮并不会影响母猪的乳腺发育，但20%的限饲将降低乳腺组织的外周组织、实质组织的重量。且乳腺外周组织重量的下降极可能与脂肪沉积减少有关。

户启蔚翻译
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