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无论大肠杆菌攻毒与否，日粮色氨酸的提高都能改善低水平大分子中性氨基酸下断奶仔猪的增重和采食量
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时间：2020-10-08
日粮色氨酸是五羟色胺的前体物质，五羟色胺是应激相关的神经递质。在通过血脑屏障时，色氨酸与其它大分子中性氨基酸（酪氨酸、异亮氨酸、亮氨酸、缬氨酸和苯丙氨酸）相互竞争；因此，调节血液循环中大分子中性氨基酸的水平会影响大脑皮层对色氨酸的利用以及五羟色胺的合成。本论文论证如下假设：在断奶仔猪攻毒大肠杆菌（ETEC；F4）下，提高日粮色氨酸，并降低大分子中性氨基酸可以提高血浆色氨酸利用率，降低应激指标，从而减少生产性能的损失。
试验选用96头雄性仔猪（21±3日龄，6.3±0.98kg，大白×长白），单栏饲喂。试验为4×2双因子试验，包括低色高氨组（0.24%SID色氨酸，5.4%SID大分子中性氨基酸）、低色低氨组（0.24%SID色氨酸，4.6%SID大分子中性氨基酸）、高色高氨组（0.34%SID色氨酸，5.4%SID大分子中性氨基酸）、高色低氨组（0.34%SID色氨酸，4.6%SID大分子中性氨基酸），以及有无大肠杆菌攻毒。攻毒组猪只在断奶后第7、8天口服0.8ml（3.6×109 cfu/ml）的大肠杆菌。
无论大分子中性氨基酸水平高低，无论在攻毒前还是攻毒后，高色氨酸组猪只血浆色氨酸含量以及色氨酸:大分子中性氨基酸显著提高（P＜0.001）。未攻毒猪只血浆色氨酸含量以及色氨酸:大分子中性氨基酸显著高于攻毒组猪只（P=0.03和0.004）。仔猪攻毒后血浆皮质醇水平显著提高（P=0.05），改变日粮色氨酸和大分子中性氨基酸水平对血浆皮质醇浓度无显著影响（P＞0.05）。攻毒24小时后，高色低氨组血浆五羟色胺水平显著高于低色低氨组和高色高氨组。相似的是，高色低氨组在三周试验期的平均日增重更高（P=0.02）。高色低氨组猪只采食量有提高的趋势（P=0.08）。
试验结果表明无论是否被攻毒，提高日粮色氨酸、降低大分子中性氨基酸，提高了血液中色氨酸水平，从而提高血浆五羟色胺浓度，改善仔猪断奶后生长性能。
Increasing dietary tryptophan in conjunction with decreasing other large neutral amino acids increases weight gain and feed intake in weaner pigs regardless of experimental infection with enterotoxigenic Escherichia coli
Dietary tryptophan (Trp) is a precursor for serotonin, a neuromediator involved in stress responses. Tryptophan competes with other large neutral amino acids (LNAA: tyrosine, isoleucine, leucine, valine, and phenylalanine) to cross the blood–brain barrier; therefore, the regulation of circulating LNAA can influence Trp availability in the cortex and serotonin biosynthesis. The hypothesis examined in this study was that increased supplementation of dietary Trp and a reduction in LNAA for weaned pigs experimentally infected with enterotoxigenic Escherichia coli (ETEC; F4) will increase Trp availability in plasma and reduce indices of the stress response, which will translate to reduced production losses. At 21 ± 3 d of age (mean ± SEM), 96 male pigs (Large White × Landrace) weighing 6.3 ± 0.98 kg (mean ± SEM) were individually penned and allocated to a 4 × 2 factorial arrangement of treatments, with respective factors being 1) four dietary standardized ileal digestible (SID) Trp and LNAA contents, being HTrpHLNAA (Low Trp-High LNAA; 0.24% SID Trp: 5.4% SID LNAA), HTrpHLNAA (Low Trp-Low LNAA; 0.24% SID Trp: 4.6% SID LNAA), HTrpHLNAA (High Trp-High LNAA; 0.34% SID Trp: 5.4% SID LNAA), and HTrpHLNAA (High Trp-Low LNAA; 0.34% SID Trp: 4.6% SID LNAA), and 2) without/with ETEC infection. Pigs were orally infected with 0.8 mL (3.6 × 109 CFU/mL) ETEC at days 7 and 8 after weaning. Pigs fed diets high in Trp irrespective of the level of LNAA (HTrpHLNAA and HTrpLLNAA) had higher plasma Trp concentrations (P < 0.001) and a Trp:LNAA ratio (P < 0.001) before infection and 6 d after infection. Following infection, noninfected pigs had higher plasma Trp (P = 0.03) and a Trp:LNAA ratio (P = 0.004) compared with pigs infected with ETEC. Plasma cortisol levels after infection were higher in ETEC-infected pigs (P = 0.05) and altering dietary Trp and LNAA concentrations did not influence (P > 0.05) plasma cortisol. Pigs fed diet HTrpLLNAA had higher serum serotonin levels 24 h after infection (P = 0.02) compared with pigs fed diets LTrpLLNAA and HTrpHLNAA. Similarly, pigs fed diet HTrpLLNAA had a higher (P = 0.02) average daily gain during the 3-wk study. Overall, average daily feed intake tended to be higher in pigs fed an HTrpLLNAA diet compared with the other diets (P = 0.08). These results suggest that the increased supplementation of dietary Trp with reduced LNAA increased circulating Trp levels that, in turn, likely caused higher serum serotonin levels, irrespective of infection with ETEC, and improved aspects of post-weaning performance.
文章来源：猪营养国际论坛
【免责声明】：文章来源于网络，我们对文中陈述观点判断保持中立，并不对文章观点负责。仅供读者参考。版权属于原作者。
试验选用96头雄性仔猪（21±3日龄，6.3±0.98kg，大白×长白），单栏饲喂。试验为4×2双因子试验，包括低色高氨组（0.24%SID色氨酸，5.4%SID大分子中性氨基酸）、低色低氨组（0.24%SID色氨酸，4.6%SID大分子中性氨基酸）、高色高氨组（0.34%SID色氨酸，5.4%SID大分子中性氨基酸）、高色低氨组（0.34%SID色氨酸，4.6%SID大分子中性氨基酸），以及有无大肠杆菌攻毒。攻毒组猪只在断奶后第7、8天口服0.8ml（3.6×109 cfu/ml）的大肠杆菌。
无论大分子中性氨基酸水平高低，无论在攻毒前还是攻毒后，高色氨酸组猪只血浆色氨酸含量以及色氨酸:大分子中性氨基酸显著提高（P＜0.001）。未攻毒猪只血浆色氨酸含量以及色氨酸:大分子中性氨基酸显著高于攻毒组猪只（P=0.03和0.004）。仔猪攻毒后血浆皮质醇水平显著提高（P=0.05），改变日粮色氨酸和大分子中性氨基酸水平对血浆皮质醇浓度无显著影响（P＞0.05）。攻毒24小时后，高色低氨组血浆五羟色胺水平显著高于低色低氨组和高色高氨组。相似的是，高色低氨组在三周试验期的平均日增重更高（P=0.02）。高色低氨组猪只采食量有提高的趋势（P=0.08）。
试验结果表明无论是否被攻毒，提高日粮色氨酸、降低大分子中性氨基酸，提高了血液中色氨酸水平，从而提高血浆五羟色胺浓度，改善仔猪断奶后生长性能。
Increasing dietary tryptophan in conjunction with decreasing other large neutral amino acids increases weight gain and feed intake in weaner pigs regardless of experimental infection with enterotoxigenic Escherichia coli
Dietary tryptophan (Trp) is a precursor for serotonin, a neuromediator involved in stress responses. Tryptophan competes with other large neutral amino acids (LNAA: tyrosine, isoleucine, leucine, valine, and phenylalanine) to cross the blood–brain barrier; therefore, the regulation of circulating LNAA can influence Trp availability in the cortex and serotonin biosynthesis. The hypothesis examined in this study was that increased supplementation of dietary Trp and a reduction in LNAA for weaned pigs experimentally infected with enterotoxigenic Escherichia coli (ETEC; F4) will increase Trp availability in plasma and reduce indices of the stress response, which will translate to reduced production losses. At 21 ± 3 d of age (mean ± SEM), 96 male pigs (Large White × Landrace) weighing 6.3 ± 0.98 kg (mean ± SEM) were individually penned and allocated to a 4 × 2 factorial arrangement of treatments, with respective factors being 1) four dietary standardized ileal digestible (SID) Trp and LNAA contents, being HTrpHLNAA (Low Trp-High LNAA; 0.24% SID Trp: 5.4% SID LNAA), HTrpHLNAA (Low Trp-Low LNAA; 0.24% SID Trp: 4.6% SID LNAA), HTrpHLNAA (High Trp-High LNAA; 0.34% SID Trp: 5.4% SID LNAA), and HTrpHLNAA (High Trp-Low LNAA; 0.34% SID Trp: 4.6% SID LNAA), and 2) without/with ETEC infection. Pigs were orally infected with 0.8 mL (3.6 × 109 CFU/mL) ETEC at days 7 and 8 after weaning. Pigs fed diets high in Trp irrespective of the level of LNAA (HTrpHLNAA and HTrpLLNAA) had higher plasma Trp concentrations (P < 0.001) and a Trp:LNAA ratio (P < 0.001) before infection and 6 d after infection. Following infection, noninfected pigs had higher plasma Trp (P = 0.03) and a Trp:LNAA ratio (P = 0.004) compared with pigs infected with ETEC. Plasma cortisol levels after infection were higher in ETEC-infected pigs (P = 0.05) and altering dietary Trp and LNAA concentrations did not influence (P > 0.05) plasma cortisol. Pigs fed diet HTrpLLNAA had higher serum serotonin levels 24 h after infection (P = 0.02) compared with pigs fed diets LTrpLLNAA and HTrpHLNAA. Similarly, pigs fed diet HTrpLLNAA had a higher (P = 0.02) average daily gain during the 3-wk study. Overall, average daily feed intake tended to be higher in pigs fed an HTrpLLNAA diet compared with the other diets (P = 0.08). These results suggest that the increased supplementation of dietary Trp with reduced LNAA increased circulating Trp levels that, in turn, likely caused higher serum serotonin levels, irrespective of infection with ETEC, and improved aspects of post-weaning performance.
文章来源：猪营养国际论坛
【免责声明】：文章来源于网络，我们对文中陈述观点判断保持中立，并不对文章观点负责。仅供读者参考。版权属于原作者。
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