Ettle T, Roth F X
Department of Animal Sciences, Division of Animal Nutrition and Production Physiology, Technical University of Munich-Weihenstephan, 85350 Freising, Germany.
J Anim Sci. 2004 Apr;82(4):1115-21. doi: 10.2527/2004.8241115x.
The aim of the present study was to investigate whether pigs prefer diets varying in Trp content and whether these preferences change with time. To that end, a feeding trial was carried out over a 6-wk period. Piglets (equal proportion of males and females) with an initial BW of 8.20 +/- 0.90 kg were randomly subdivided into four groups of 12 pigs each. Two reference groups were fed (as-fed basis) either 0.11% Trp (Trp-deficient) or 0.20% Trp (Trp-adequate) diets. Two other groups had a choice of two diets containing either 0.11 or 0.16% Trp (Trp-choice 1), or 0.11 or 0.20% Trp (Trp-choice 2). Average daily feed intake reached 335 and 366 g in pigs fed Trp-deficient and Trp-choice 1 diets, respectively. For Trp-choice 2 and Trp-adequate diets, a higher (P < 0.05) feed intake of 589 and 645 g/d, respectively, was observed. Piglets on Trp-choice 1 and Trp-choice 2, respectively, selected 87 and 93% of the higher Trp diet. Resulting Trp contents of total diets were 0.15 and 0.19% (as-fed basis) in Trp-choice 1 and Trp-choice 2, respectively. In wk 1, pigs on Trp-choice 2 chose lower proportions of the Trp-deficient feed (31% of total diet) than did pigs on Trp-choice 1 (44%), but at the end of the experiment, pigs of both groups almost exclusively chose the feed with the higher Trp content (96 and 98% for Trp-choice 1 and 2). Pigs on Trp-choice 1 had an ADG of 218 g, which was only slightly above the ADG of Trp-deficient pigs (198 g). Pigs on Trp-choice 2 and Trp-adequate diets had ADG of 404 and 458 g, respectively, which were higher (P < 0.05) than those observed for Trp-deficient and Trp-choice 1 groups. Plasma Trp concentrations in Trp-choice 2 and Trp-adequate groups (9.21 and 9.01 micromol/mL, respectively) were higher (P < 0.05) than in Trp-deficient and Trp-choice 1 groups (5.88 and 4.96 micromol/mL, respectively). Conversely, the sum of essential AA showed a higher (P < 0.05) concentration in plasma from pigs on the Trp-deficient and Trp-choice 1 diets than in plasma from pigs on Trp-choice 2 and Trp-adequate diets. Nutritional depletion of Trp influences the food selection behavior of piglets. Results of growth performance and the dietary preferences suggest that piglets are able to detect Trp-deficiency-induced metabolic changes and respond with an aversion against the Trp-deficient diet.
本研究的目的是调查猪是否偏好色氨酸含量不同的日粮，以及这些偏好是否随时间变化。为此，进行了为期6周的饲养试验。初始体重为8.20±0.90千克的仔猪（公母比例相同）被随机分为四组，每组12头猪。两个对照组分别饲喂（以风干基础计）0.11%色氨酸（色氨酸缺乏）或0.20%色氨酸（色氨酸充足）的日粮。另外两组可以选择两种日粮，一种含0.11%色氨酸，另一种含0.16%色氨酸（色氨酸选择1组），或者一种含0.11%色氨酸，另一种含0.20%色氨酸（色氨酸选择2组）。饲喂色氨酸缺乏日粮和色氨酸选择1组日粮的猪，平均日采食量分别达到335克和366克。对于色氨酸选择2组日粮和色氨酸充足日粮，观察到采食量较高（P<0.05），分别为589克/天和645克/天。色氨酸选择1组和色氨酸选择2组的仔猪分别选择了87%和93%的高色氨酸日粮。色氨酸选择1组和色氨酸选择2组日粮中色氨酸的最终含量（以风干基础计）分别为0.15%和0.19%。在第1周，色氨酸选择2组的猪选择色氨酸缺乏饲料的比例（占总日粮的31%）低于色氨酸选择1组的猪（44%），但在试验结束时，两组猪几乎都只选择了色氨酸含量较高的饲料（色氨酸选择1组和色氨酸选择2组分别为96%和98%）。色氨酸选择1组的猪平均日增重为218克，仅略高于色氨酸缺乏组猪的平均日增重（198克）。色氨酸选择2组和色氨酸充足日粮组的猪平均日增重分别为404克和458克，高于（P<0.05）色氨酸缺乏组和色氨酸选择1组。色氨酸选择2组和色氨酸充足组的血浆色氨酸浓度（分别为9.21微摩尔/毫升和9.01微摩尔/毫升）高于（P<0.05）色氨酸缺乏组和色氨酸选择1组（分别为5.88微摩尔/毫升和4.96微摩尔/毫升）。相反，色氨酸缺乏组和色氨酸选择1组日粮的猪血浆中必需氨基酸的总和浓度高于（P<0.05）色氨酸选择2组和色氨酸充足日粮组的猪血浆。色氨酸的营养缺乏会影响仔猪的食物选择行为。生长性能和日粮偏好的结果表明，仔猪能够检测出色氨酸缺乏引起的代谢变化，并对色氨酸缺乏日粮产生厌恶反应。
