青春期日糧蛋白質(zhì)水平和限飼對(duì)后備母豬乳腺發(fā)育的影響（原創(chuàng)）

畜牧編輯

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

　　本試驗(yàn)的研究目的是評(píng)估后備母豬青春期日糧蛋白質(zhì)水平及限飼對(duì)母豬乳腺發(fā)育的影響。

　　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日齡雜交母豬。兩種顆粒料分別為：高蛋白日糧（ME13.8MJ/kg，總賴氨酸1.0%，CP18.7%）；低蛋白日糧（ME13.8MJ/kg，總賴氨酸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種處理分別為：自由采食高蛋白日糧至屠宰（n=22，T1）；自由采食高蛋白日糧至150日齡，后自由采食低蛋白日糧至屠宰（n=20，T2）；自由采食低蛋白日糧至屠宰（n=21，T3）；20%限飼高蛋白日糧至屠宰（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.

　　試驗(yàn)?zāi)肛i于第1次或第2次發(fā)情后的8±1天（202.7 ± 14.5日齡）屠宰。記錄母豬第90日齡、150日齡、屠宰時(shí)的體重、背膘厚，并同時(shí)收集頸靜脈血液用于檢測(cè)其中激素水平。屠宰時(shí)切割乳腺組織，分析乳腺外周、實(shí)質(zhì)組織中蛋白質(zhì)、脂肪、干物質(zhì)、DNA、蛋白質(zhì)/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組母豬150日齡、屠宰時(shí)體重、背膘厚顯著低于其它3組。

　　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).

　　各組母豬屠宰時(shí)血液催乳素、IGF-I、葡萄糖濃度均無顯著差異，但T4組母豬血液leptin水平顯著低于T3組。

　　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組母豬乳腺外周組織重量顯著低于其它3組，導(dǎo)致乳腺實(shí)質(zhì)組織重量也低于其它3組，但差異不顯著。

　　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.

　　總結(jié)：后備母豬青春期飼喂低蛋白日糧并不會(huì)影響母豬的乳腺發(fā)育，但20%的限飼將降低乳腺組織的外周組織、實(shí)質(zhì)組織的重量。且乳腺外周組織重量的下降極可能與脂肪沉積減少有關(guān)。

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