日糧中添加亮氨酸和色氨酸對生長豬血清素代謝和生長性能的影響

發(fā)布單位:天津瑞孚農牧科技集團有限公司

查看次數：6519

時間：2022-02-08
本試驗旨在驗證生長豬高亮氨酸日糧中增加色氨酸水平，可以防止血漿血清素和下丘腦血清素濃度下降，進而維持動物的生長性能的假設。

選取144頭生長豬（初始體重為28.2±1.9 kg），采用完全隨機區(qū)組設計，分為9個處理，每個處理8欄，每欄2頭豬。采用3（3個水平的亮氨酸（101%、200%或299%SID Leu:Lys）） × 3（3個水平的色氨酸（18%、23%或28% SID Trp:Lys））析因法配制9種試驗日糧，配制滿足SID Leu和 SID Trp需求的基礎日糧，并在基礎日糧中添加L-Leu和(或)L-Trp配制其他8種試驗日糧。在試驗開始和21 d結束時記錄豬的體重。試驗最后一天，每個豬圈宰殺1頭豬，采集血液和下丘腦樣本，測定血漿尿素氮、血漿血清素和下丘腦血清素濃度。

結果表明，日糧Trp水平的提高增加了下丘腦血清素水平（P < 0.05），而平均日增重（ADG）和平均日采食量（ADFI）的提高僅在Leu水平超標時顯著（P < 0.05）。增加日糧Leu降低了ADG、ADFI和下丘腦血清素（P < 0.05）。但添加299% SID Leu:Lys時，日糧Trp對ADG和ADFI的影響大于添加101% SID Leu:Lys時（交互作用，P < 0.05）。日糧Leu對血漿Leu濃度有正向影響，Trp對血漿Leu濃度有負向影響，但添加299% SID Leu:Lys對血漿Leu濃度的負向影響大于添加101% SID Leu:Lys 組（交互作用，P < 0.05）。日糧Trp和Leu水平的提高對血漿Trp濃度有顯著的正向影響，但Leu水平在101% SID Leu:Lys時，血漿Trp濃度的提高高于299% SID Leu:Lys時（交互作用，P < 0.05）。

綜上所述，日糧中提高Leu含量降低了ADG、ADFI和下丘腦血清素濃度，并影響了幾種必需氨基酸的代謝，但添加Trp部分克服了過量Leu的負面影響。這說明Leu在調節(jié)下丘腦血清素和采食量方面的重要性。


Effects of dietary leucine and tryptophan on serotonin metabolism and growth performance of growing pigs 
An experiment was conducted to test the hypothesis that increased dietary Trp is needed in high-Leu diets for growing pigs to prevent a drop in plasma serotonin and hypothalamic serotonin concentrations and to maintain growth performance of animals. A total of 144 growing pigs (initial weight: 28.2 ± 1.9 kg) were assigned to 9 treatments in a randomized complete block design with 2 blocks, 2 pigs per pen, and 8 replicate pens per treatment. The 9 diets were formulated in a 3 × 3 factorial with 3 levels of dietary Leu (101%, 200%, or 299% standardized ileal digestible [SID] Leu:Lys), and 3 levels of dietary Trp (18%, 23%, or 28% SID Trp:Lys). A basal diet that met requirements for SID Leu and SID Trp was formulated and 8 additional diets were formulated by adding crystalline L-Leu and (or) L-Trp to the basal diet. Individual pig weights were recorded at the beginning of the experiment and at the conclusion of the 21-d experiment. On the last day of the experiment, 1 pig per pen was sacrificed, and blood and hypothalamus samples were collected to measure plasma urea N, plasma serotonin, and hypothalamic serotonin concentrations. Results indicated that increasing dietary Trp increased (P < 0.05) hypothalamic serotonin, whereas increases (P < 0.05) in average daily gain (ADG) and average daily feed intake (ADFI) were observed only in pigs fed diets containing excess Leu. Increasing dietary Leu reduced (P < 0.05) ADG, ADFI, and hypothalamic serotonin. However, the increase in ADG and ADFI caused by dietary Trp was greater if 299% SID Leu:Lys was provided than if 101% SID Leu:Lys was provided (interaction, P < 0.05). Plasma Leu concentration was positively affected by dietary Leu and negatively affected by dietary Trp, but the negative effect of Trp was greater if 299% SID Leu:Lys was provided than if 101% SID Leu:Lys was provided (interaction, P < 0.05). Plasma concentration of Trp was positively affected by increased dietary Trp and increased dietary Leu, but the increase in plasma concentration of Trp was greater if Leu level was at 101% SID Leu:Lys ratio than at 299% SID Leu:Lys ratio (interaction, P < 0.05). In conclusion, increased dietary Leu reduced ADG, ADFI, and hypothalamic serotonin concentration, and influenced metabolism of several indispensable amino acids, but Trp supplementation partly overcame the negative effect of excess Leu. This demonstrates the importance of Trp in regulation of hypothalamic serotonin, and therefore, feed intake of pigs.

文章來源：豬營養(yǎng)國際論壇
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