Meunier-Salaün M C, Monnier M, Colléaux Y, Sève B, Henry Y
INRA, Station de Recherches Porcines, St-Gilles, L'Hermitage, France.
J Anim Sci. 1991 Sep;69(9):3689-98. doi: 10.2527/1991.6993689x.
The behavioral reactivity in an "open-field" test and plasma cortisol levels were studied in 72 pigs from 12 litters fed for 3 wk one of three diets with different levels of tryptophan: deficient (.14%), adequate (.23%), or excess (.32%). "Open-field" tests were performed three times: 5 d (day W + 5), 23 d (day W + 23) and 45 d (day W + 45) after weaning. The exploration time and the number of grunts provided an adequate measure of the individual emotional reactivity at day W + 5. Significant correlations were obtained between exploration time and the number of grunts at each time (r = -.83 at day W + 5; r = -.46 at day W + 23; r = -.71 at day W + 45). The distinction between animals remained (P less than .05) in terms of exploration time at both 23 and 45 d after weaning. At day W + 23, exploration time was lower in the group fed the adequate diet than in the two other groups. This effect was maintained subsequently after feeding all pigs the same adequate diet (day W + 45). In 36 pigs slaughtered at day W + 23, brain TRP concentration was higher with the excess dietary TRP than with deficient or adequate levels. Conversely, other plasma amino acids (particularly threonine) accumulated only in the brains of pigs fed the deficient diet. Plasma cortisol level assayed at weaning (W) and 2 wk later increased with age and was higher in 16-h fasted (day W + 15) than in 3-h fasted (day W + 17) pigs. Correlations were observed within litters in the fasting state, between the cortisol level and behavioral traits measured at day W + 23 (r = .70 for number of grunts, r = -.60 for exploration time). Dietary TRP did not affect the plasma cortisol level irrespective of the nutritional state after weaning. However, an interaction was noted between plasma cortisol and TRP status (P less than .05). Although dietary TRP induced large variations in brain amino acids and 5-hydroxyindole concentrations, changes in behavioral and cortisol responses were relatively minor.
在“旷场”试验中的行为反应性和血浆皮质醇水平，在来自12窝的72头仔猪中进行了研究，这些仔猪被喂食三种不同色氨酸水平的日粮之一，为期3周：缺乏（0.14%）、充足（0.23%）或过量（0.32%）。“旷场”试验在断奶后5天（W+5天）、23天（W+23天）和45天（W+45天）进行了三次。在W+5天，探索时间和呼噜声次数能充分衡量个体的情绪反应性。每次测量时，探索时间和呼噜声次数之间都存在显著相关性（W+5天时r=-0.83；W+23天时r=-0.46；W+45天时r=-0.71）。在断奶后23天和45天，就探索时间而言，动物之间的差异仍然存在（P<0.05）。在W+23天，喂食充足日粮的组的探索时间低于其他两组。在给所有仔猪喂食相同的充足日粮后（W+45天），这种效应随后得以维持。在W+23天宰杀的36头仔猪中，日粮色氨酸过量时脑内色氨酸浓度高于缺乏或充足水平时。相反，其他血浆氨基酸（特别是苏氨酸）仅在喂食缺乏日粮的仔猪脑中积累。在断奶时（W）和2周后测定的血浆皮质醇水平随年龄增加，并且在禁食16小时（W+15天）的仔猪中高于禁食3小时（W+17天）的仔猪。在禁食状态下，窝内观察到皮质醇水平与W+23天测量的行为特征之间的相关性（呼噜声次数r=0.70，探索时间r=-0.60）。断奶后的营养状态如何，日粮色氨酸均不影响血浆皮质醇水平。然而，注意到血浆皮质醇和色氨酸状态之间存在相互作用（P<0.05）。尽管日粮色氨酸会引起脑内氨基酸和5-羟吲哚浓度的大幅变化，但行为和皮质醇反应的变化相对较小。
