Effects of supplemental L-tryptophan on serotonin, cortisol, intestinal integrity, and behavior in weanling piglets
Effects of supplemental L-tryptophan on serotonin, cortisol, intestinal integrity, and behavior in weanling piglets
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DOI：
10.2527/2006.844963x
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发表时间：
2006-04-01
影响因子：
3.3
通讯作者：
Southern, LL
中科院分区：
文献类型：
--
作者：
Koopmans, SJ;Guzik, AC;Southern, LL
在集约化养猪场，当仔猪断奶和混合时会出现压力。在这项研究中，我们调查了这种压力是否可以降低饮食中色氨酸水平的升高。在混合之前和之后，在保育猪中测试补充膳食色氨酸（5g/kg饲料，以饲喂为基础）对神经内分泌系统、肠道完整性、行为和生长性能的影响。混合发生在断奶和饮食引入后5天。在第4、5和6天，与对照猪相比，Trp喂养猪的血浆Trp浓度约升高2倍（68 +/- 7 vs. 32 +/- 2 μ mol/L; P < 0.001），通过5-羟吲哚乙酸：5-羟色胺测定的下丘脑5-羟色胺周转率增加38%（P < 0.001），肠绒毛高度：隐窝深度增加11%至18%（P < 0.05）。在混合前（d 4）和混合后（d 5），Trp喂养的猪与对照猪相比，唾液而非血浆皮质醇浓度降低（P < 0.02）约2倍。肠旁细胞（辣根过氧化物酶）和跨细胞（异硫氰酸荧光素）运输的大分子不受饮食治疗，但混合诱导2倍减少（P < 0.05）的跨细胞运输。混合时的行为反应（卧和站立）不受饮食处理的影响，除了在饮食引入后第10天，补充色氨酸诱导更多的卧和更少的站立（P < 0.02）。平均日增重和ADFI在各组间差异不显著（P > 0.10）。总之，补充膳食色氨酸（5 g/kg）仔猪增加下丘脑肾上腺素能活动，减少唾液皮质醇反应混合，改善肠道形态，并减少体力活动后10天的饮食介绍。因此，饮食中含有高色氨酸水平的改善神经内分泌成分的压力和增加胃肠道的鲁棒性，但不影响行为反应在保育猪断奶和混合。
Stress occurs in intensive pig farming when piglets are weaned and mixed. In this study, we investigated whether this stress might be reduced with elevated dietary levels of Trp. The effects of supplemental dietary Trp (5 g/kg of feed, as-fed basis) were tested on the neuroendocrine system, intestinal integrity, behavior, and growth performance in nursery pigs, both before and after mixing. Mixing occurred 5 d after weaning and diet introduction. On d 4, 5, and 6, Trp-fed pigs vs. control pigs showed approximately a 2-fold elevation in plasma Trp concentrations (68 +/- 7 vs. 32 +/- 2 mu mol/L; P < 0.001), a 38% increase in hypothalamic serotonin turnover as measured by 5-hydroxyindoleacetic acid:5-hydroxytryptamine (P < 0.001), and an 11 to 18% increase (P < 0.05) in the intestinal villus height:crypt depth. Before (d 4) and at (d 5) mixing, saliva but not plasma cortisol concentrations were reduced (P < 0.02) by approximately 2-fold in Trp-fed pigs vs. control pigs. Intestinal paracellular (horseradish peroxidase) and transcellular (fluorescein isothiocyanate) transport of macromolecules were not affected by dietary treatment, but mixing induced a 2-fold reduction (P < 0.05) in transcellular transport. Behavioral responses (lying and standing) at mixing were not affected by dietary treatment, except on d 10 after diet introduction when Trp supplementation induced more lying and less standing (P < 0.02). Average daily gain and ADFI were not different among dietary groups (P > 0.10). In conclusion, supplemental dietary Trp (5 g/kg) to piglets increased hypothalamic serotonergic activity, reduced the salivary cortisol response to mixing, improved intestinal morphology, and reduced physical activity 10 d after diet introduction. Consequently, diets containing high Trp levels improved neuroendocrine components of stress and increased gastrointestinal robustness but did not affect behavioral reactivity in nursery pigs during weaning and mixing.