第199期：利用指示劑氨基酸氧化法研究小型犬、中型犬和大型成犬色氨酸需要量

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2019. J. Anim. Sci. 97(8):3274–3285

DOI：https://doi.org/10.1093/jas/skz142

利用指示劑氨基酸氧化法研究小型犬、中型犬和大型成犬色氨酸需要量

James R Templeman, Wilfredo D Mansilla, Lisa Fortener, Anna K Shoveller

在犬的各個(gè)生長(zhǎng)階段，色氨酸都是必須氨基酸；盡管生長(zhǎng)犬對(duì)色氨酸的需要量來(lái)源于3個(gè)生長(zhǎng)試驗(yàn)，但是對(duì)成犬維持需要量的仍沒(méi)有相關(guān)試驗(yàn)數(shù)據(jù)。

本試驗(yàn)通過(guò)指示劑氨基酸氧化法研究了3個(gè)不同品種成犬的色氨酸需要量。試驗(yàn)選用4頭切除卵巢或去勢(shì)的微型臘腸犬（5.28±0.29kg體重）、4頭切除卵巢的比格（9.32±0.41kg體重）、5頭去勢(shì)的拉布拉多獵犬（30.51±2.09kg體重）。試驗(yàn)開(kāi)始前飼喂14天的色氨酸充足基礎(chǔ)日糧（色氨酸含量0.482%，干基）。隨后所有犬飼喂色氨酸中度缺乏日糧2天（色氨酸含量0.092%，干基），然后將犬隨機(jī)分至7種日糧處理，日糧色氨酸水平分別為0.092、0.126、0.148、0.182、0.216、0.249、0.283%（干基），所有犬經(jīng)過(guò)所有色氨酸水平處理。試驗(yàn)日糧飼喂兩天后，犬經(jīng)過(guò)獨(dú)立的指示劑氨基酸氧化試驗(yàn)?？?a href="http://m.livemosquitofree.com/feed" target="_blank" class="relatedlink">飼料量分成相同的13份；在第6餐，日糧中額外添加L-[1-13C]-苯丙氨酸（9.40mg/kg體重），隨后的每頓日糧中添加L-[1-13C]-苯丙氨酸（2.4mg/kg體重）。通過(guò)呼吸樣品中的豐度測(cè)量同位素穩(wěn)態(tài)下13-CO2的總產(chǎn)量，通過(guò)間接側(cè)熱法檢測(cè)CO2總產(chǎn)量。通過(guò)兩相線性回歸模型測(cè)定色氨酸的維持需要量和95%置信區(qū)間。

微型臘腸犬、比格犬、拉布拉多犬的平均色氨酸需要量為0.154、0.218、0.157%（干基），95%置信區(qū)間上限為0.187、0.269、0.204%（干基）?？傊?，比格犬色氨酸需要量高于拉布拉多和微型臘腸犬，并且均高于NRC和AAFCO的現(xiàn)有推薦值。

Tryptophan requirements in small, medium, and large breed adult dogs using the indicator amino acid oxidation technique

James R Templeman,  Wilfredo D Mansilla,  Lisa Fortener, Anna K Shoveller

Tryptophan (Trp) is an indispensable amino acid(AA) for dogs of all life stages; however, although Trp requirements for growing dogs are derived from 3 dose–response studies, there are no empiricaldata on Trp requirements for adult dogs at maintenance. The study objective was to determine Trp requirements of adult dogs of 3 different breeds using the indicator amino acid oxidation (IAAO) technique. Four spayed or neutered Miniature Dachshunds (5.28 ± 0.29 kg BW), 4 spayed Beagles (9.32 ± 0.41 kg BW), and 5 neutered Labrador Retrievers (30.51 ± 2.09 kg BW) were used. After a 14-dadaptation to a Trp-adequate basal diet (Trp = 0.482% dry matter), all dogs were fed a mildly Trp-deficient diet for 2 d (Trp = 0.092% dry matter) before being randomly allocated to receiving 1 of 7 concentrations of Trp supplementation (final Trp content in experimental diets was 0.092, 0.126,0.148, 0.182, 0.216, 0.249, and 0.283% dry matter) and all dogs received all Trp treatments. After 2-d adaptation to the experimental diets, dogs underwent individual IAAO studies. Total feed was divided in 13 equal meals; at the sixth meal, dogs were fed a bolus of L-[1-13C]-Phenylalanine (Phe) (9.40 mg/kg BW), and thereafter, L-[1-13C]-Phe was supplied (2.4 mg/kg BW) with every meal. Total production of 13CO2 during isotopic steady state was determined by enrichment of 13CO2 in breath samples and total production of CO2 measured using indirect calorimetry. The maintenance requirement for Trp and the 95% confidence interval (CI) were determined using a 2-phase linear regression model. Mean Trp requirements were estimated at 0.154, 0.218, and 0.157%(dry-matter) for Dachshunds, Beagles, and Labradors, respectively. The upper 95% CI were 0.187, 0.269, and 0.204% (dry-matter) for Dachshunds, Beagles, and Labradors. In conclusion, estimated Trp requirements are higher for Beagles compared with Labradors or Dachshunds, and all estimated requirements are higher than those currently recommended by the NRC and AAFCO.

翻譯：上海亙泰    轉(zhuǎn)自：豬營(yíng)養(yǎng)國(guó)際論壇