Nadal M R, Thompson D L, Kincaid L A
Department of Animal Science, Louisiana State University Agricultural Center, Baton Rouge 70803, USA.
J Anim Sci. 1997 Mar;75(3):736-44. doi: 10.2527/1997.753736x.
Two experiments were conducted to determine 1) the prolactin response to different kinds of feedstuffs in stallions and 2) the effects of total feed deprivation on prolactin secretion in mares and its interaction with the prolactin response to feeding. Experiment 1 was performed with stallions as a 6 x 6 Latin square: A) no feed; B) pelleted feed fed to meet 82.5% of the horses' CP requirements; C) pelleted feed at 25% of the amount in B; D) pelleted feed as in B plus water ad libitum; E) cracked corn at the weight in B; and F) chopped alfalfa at the weight in B. The positive prolactin responses (P < .05) to feeding were similar for treatments B through F. The insulin response to feeding was highest (P < .05) in stallions fed water with the pelleted feed. In Exp. 2, 72 h of feed deprivation did not affect (P > .1) daily prolactin secretion. Feeding of a meal on the 3rd d of deprivation increased (P < .05) plasma prolactin, insulin, and glucose concentrations similarly in all mares. There was a positive growth hormone response (P < .1) after feeding in feed-deprived mares but not in fed mares. The prolactin response (P < .001) to thyrotropin-releasing hormone was greater (P = .083) for feed-deprived mares than for controls, whereas the response to sulpiride (P < .001) only tended to differ (P = .16) between groups. We conclude that prolactin secretion may be stimulated by aspects of eating other than the feedstuff itself. Total feed deprivation had little effect on the subsequent prolactin response to a meal or to other known secretagogues.
进行了两项实验，以确定：1）公马对不同种类饲料的催乳素反应；2）完全禁食对母马催乳素分泌的影响及其与催乳素对进食反应的相互作用。实验1以公马为实验对象，采用6×6拉丁方设计：A）不喂食；B）投喂颗粒饲料，满足马匹82.5%的粗蛋白需求；C）投喂颗粒饲料，量为B组的25%；D）投喂与B组相同的颗粒饲料并自由饮水；E）投喂与B组重量相同的碎玉米；F）投喂与B组重量相同的苜蓿草。B至F组对进食的催乳素阳性反应（P<0.05）相似。在投喂颗粒饲料并饮水的公马中，进食后的胰岛素反应最高（P<0.05）。在实验2中，禁食72小时对每日催乳素分泌无影响（P>0.1）。在禁食第3天喂食一顿，所有母马的血浆催乳素、胰岛素和葡萄糖浓度均有相似程度的升高（P<0.05）。禁食母马进食后有阳性生长激素反应（P<0.1），而喂食母马则无。禁食母马对促甲状腺激素释放激素的催乳素反应（P<0.001）比对照组更大（P=0.083），而对舒必利的反应（P<0.001）两组间仅存在趋势性差异（P=0.16）。我们得出结论，催乳素分泌可能受到进食过程中除饲料本身之外的其他因素刺激。完全禁食对随后进食或其他已知促分泌素引起的催乳素反应影响不大。
