日本鵪鶉生長期飼糧中理想可消化胺基酸組成之建立

Abstract

本研究旨在探討日本鵪鶉對各必需胺基酸之可消化需要量以及整體必需胺基酸對總胺基酸之比例，藉以建立飼糧中理想胺基酸組成。本研究分為五個試驗，皆以4日齡之 English White 品系日本鵪鶉（Coturnix japonica）為試驗動物，試驗為期7日，至10日齡結束。試驗一以滿足NRC（1994）所推薦生長期飼糧中各營養分需要量之玉米-大豆粕實用飼糧，餵飼日本鵪鶉，並根據其每日之體重、採食量與飼糧之可代謝能濃度，計算4至10日齡鵪鶉平均每日每公斤代謝體重所對應之可代謝能需要量（k 值），經檢測後結果為467.08 ± 33.57 kcal ME/kg^0.75。試驗二參考NRC （1994）所載的各必需胺基酸推薦量，配製五組半純化飼糧，彼等各必需胺基酸之濃度分別為推薦量之50%、75%、100%、125%或150%，餵飼4至10日齡之English White日本鵪鶉。試驗結束後，使用比較性屠宰法計算其體氮蓄積速率，繼之以二次曲線模型進行統計分析。結果顯示，當飼糧中各必需胺基酸濃度達到NRC （1994）推薦量的113.17%時，日本鵪鶉將呈現最佳的體氮蓄積率。試驗三以滿足NRC （1994）對各必需胺基酸推薦量之113.17%之半純化飼糧，餵飼4至10日齡之日本鵪鶉，藉以檢測該飼糧之可代謝能濃度，並以此計算出鵪鶉平均每日每公斤代謝體重所對應之可代謝能需要量（k 值）。經檢測後結果顯示，該半純化飼糧之表面可代謝能濃度為3450.07 ± 64.45 kcal/kg，而k 值為466.23 ± 21.27 kcal ME/kg^0.75。試驗四共22組。其中一組於試驗開始時犧牲，提供計算起始體氮之依據。對照組飼糧則為試驗三所檢測之半純化飼糧。其餘組別為缺乏組，兩兩成對，以一種必需胺基酸當成唯一的限制胺基酸，分別為對照組濃度的50或60%。依據k 值、半純化飼糧之可代謝能濃度與日本鵪鶉個別代謝體重，計算每日應有之採食量，進行餵飼。於試驗結束後，以比較性屠宰法分析其體氮蓄積率。將兩兩成對之各必需胺基酸缺乏組別的限制胺基酸濃度與所對應的體氮蓄積率，進行直線迴歸，再與對照組體氮蓄積率的水平線相交，所得交點的x 軸之對應值，即為生長中鵪鶉每日每公斤代謝體重，對此必需胺基酸之維持加生長的需要量。而各迴歸直線斜率之倒數與迴歸直線對x 軸的截距，則分別代表日本鵪鶉每日每公斤代謝體重，對此必需胺基酸用於生長與維持之需要量。另將所求得之生長、維持、維持加生長之各必需胺基酸需要量，除以離胺酸組所對應之數值，即分別得到4至10日齡鵪鶉維持加生長所需之理想必需胺基酸組成為Lys：Arg：SAA：His：Trp：Leu：AAA：Ile：Thr：Val = 100：91：62：26：17：121：157：69：75：69；生長所需之組成為100：89：44：20：17：99：102：74：67：76；維持所需之組成為100：98：135：50：9：209：375：49：104：40。試驗五調整飼糧中非必需胺基酸之濃度，並應用試驗四所求得之4 至10 日齡鵪鶉對各必需胺基酸生長加維持之理想組成為基礎，配製出五種試驗飼糧，分別為飼糧中整體必需胺基酸佔總胺基酸之比例（E：T）為0.62、0.48、0.39、0.32 或0.28 之處理組飼糧。以管飼輔助任飼進行試驗，試驗結果顯示當E：T小於0.40時，隨著飼糧中E：T 下降，體內的氮蓄積速率呈線性上升（P < 0.05），而E：T小於0.47時，飼糧氮的利用效率則呈線性下降（P < 0.05）。達到最佳體氮蓄積速率與最佳飼糧氮利用效率之轉折點，分別為0.40與0.47。 綜上所述，本研究所發現飼糧中理想胺基酸之組成，可當成評估生長期鵪鶉飼料中可被消化必需胺基酸組成良窳之依據，以期能降低飼糧中粗蛋白質之濃度，並使含氮廢物之排放量減少，進而建立鵪鶉最佳之生產效能。

The aim of the current study was to investigate the digestible requirements of the integrity of individual essential amino acids for Japanese quail to establish the ideal amino acid pattern (IAAP) in diets. This study consisted of five trials whose animal model was used the 4- 10 day old English White strain of Japanese quail (Coturnix japonica) as experimental animals. In the first trial, Japanese quail was fed with a practical diet, basing on corn and soybean, which met the requirements of nutrients in the growth period recommended by NRC (1994). The requirement of metabolizable energy, k value, for daily maintenance plus growth basing on metabolic body weight was computed according to dietary concentration of metabolizable energy and the daily body weight and feed intake of quail. A result showed k value as 467.08 ± 33.57 kcal ME/kg^0.75. The second trial was to investigate the integrity of requirements recommended by NRC (1994) for individual essential amino acids. Quail receiving diets containing 50, 75, 100, 125, or 150% of requirements of entire essential amino acids recommended by NRC (1994) from d4 to 10. The accumulation rates of body nitrogen calculated by the methodology of comparative slaughter were computed according to a quadratic regression model and the x coordinate of the inflection point of a corresponding quadratic curve was 113.17%. It implied that the best accumulation rate of body nitrogen would be achieved when the dietary levels of individual essential amino acids reached entirely to 113.17% of requirements recommended by NRC (1994). In the third trial, Japanese quails ingested a semi- synthetic diet containing 113.17% of the entire requirements of individual essential amino acids recommended by NRC (1994) for detected the apparent metabolizable energy level of the diet and it was as 3450.07 ± 64.45 kcal/kg. A k value was also computed as 466.23 ± 21.27 kcal ME/kg^0.75 according to dietary concentration of metabolizable energy and the daily body weight and feed intake of quail. In the fourth trial, 22 treatments were conducted. One set of quail was sacrificed in the beginning of the test to provide a basis for computing the initial body nitrogen mass of the rest quail. The percentages of entire essential amino acids in a control diet was designed as 113.17% referring to the quail requirements suggested by NRC (1994). Individual essential amino acids were assigned to be the only limiting amino acid in corresponding deficiency groups, and the deficiency level was 50 or 60% of the control group, respectively. According to the apparent metabolizable energy level of the semi-synthetic diet, the individual metabolic body weight of individual quail, and the k value obtained in trial 3, daily feed intake was computed for feeding. In the end of the experiment, the nitrogen retention rate was calculated by comparative slaughtering. The x coordinate of an intersection for each straight line, resulting from every two deficient groups with the same limiting amino acid but at different levels, with a horizontal line from the response of the control group represented the daily requirement for the corresponding essential amino acid based on metabolic body weight for growth plus maintenance. The x-intercept and the reciprocal of slope for each straight line stood for the respective requirement for maintenance and growth, separately, corresponding to the examined essential amino acid. Each amino acid requirement obtained for growth, maintenance, and growth plus maintenance were divided by the value of lysine to obtain the ideal essential amino acid pattern (IEAAP) for growth plus maintenance from 4 to 10 days of age was Lys: Arg: SAA: His: Trp: Leu: AAA: Ile: Thr: Val =100：91：62：26：17：121：157：69：75：69, respectively, for growth, was 100：89：44：20：17：99：102：74：67：76, respectively, and for maintenance was 100：98：135：50：9：209：375：49：104：40. In the final trial, The ratio of total essential amino acids to total amino acids (E:T) was manipulated by adjusting the levels of dietary non-essential amino acids while maintaining the individual essential amino acid requirement levels for growth plus maintenance originating from the trial 4. The E:T ratio was designed as 0.62, 0.48, 0.39, 0.32 or 0.28 for each treatment. The results showed that a decrease in the E:T ratio was accompanied by a significantly linear (P < 0.05) increase in body nitrogen retention rate until the E:T ratio smaller than 0.40 while a significantly linear (P < 0.05) decrease in dietary nitrogen utilization efficiency until the E:T ratio larger than 0.47. The optimal ratios of E:T were 0.40 and 0.47 for body nitrogen retention rate and dietary nitrogen utilization efficiency, respectively. To sum up, the results obtained will be as a criterion to evaluate the pattern of digestible ideal amino acids in practical diets for reducing the dietary level of crude protein and the nitrogen emission of excrement whereas lifting the efficiency of production.