添加不同含量綠茶副茶粉對日本鵪鶉體內脂肪蓄積與蛋黃膽固醇含量之影響

Abstract

本試驗旨在探討添加不同含量綠茶副茶粉對日本鵪鶉體內脂肪蓄積與蛋黃膽固醇含量之影響。試驗分成二個階段：第一階段為生長試驗為期5週，將320隻1週齡之日本鵪鶉逢機平均分入5組，分別採食含綠茶副茶粉0、1、2、4或8%之飼糧，每組8欄，檢測每週之生長性能，並於4週齡時犧牲全部雄鳥，每組隨機挑選16隻公鳥採樣，檢測其血脂濃度與肝臟脂肪含量；至於雌鳥則持續進行完成隨後兩週之生長試驗。第二階段為6到16週齡之產蛋試驗，實驗動物為第一階段試驗所保留的雌日本鵪鶉，延續先前的處理，但每個處理組之雌鳥重新逢機分入6欄；試驗期間每兩週檢測其產蛋性能以及蛋黃的重量、脂肪含量與膽固醇含量；並且於16週齡時，每組隨機挑選16隻雌鳥犧牲採樣，檢測其血脂濃度、腹脂重與肝臟脂肪含量。 結果顯示，日本鵪鶉於4週齡之體重、1到4週齡之體增重與採食量，會隨飼糧內綠茶副茶粉含量上升而呈線性下降（P < 0.05）；此外，餵飼含超過2%的綠茶副茶粉飼糧會使雄鳥的肝臟變重，也會造成體重之相對重量變大，且使得6週齡雌鳥之體重下降。除此之外，在雌日本鵪鶉之產蛋試驗發現，於6到16週齡期間之平均蛋重會隨著飼糧內綠茶副茶粉含量之上升而呈直線下降（P < 0.05），然而其隻日產蛋率與蛋量則在綠茶副茶粉濃度超過2%時才會逐漸下降（P < 0.05）；至於每日採食量、肝臟重、肝臟佔體重比例以及血漿中高密度脂蛋白固醇濃度等，皆與飼糧內綠茶副茶粉的含量呈二次曲線關係（P < 0.05），會隨著飼糧內綠茶副茶粉含量上升逐漸下降至4%，然而8%組者則呈現回升。 隨著綠茶副茶粉在飼糧內添加的量上升，生長階段雄鳥肝臟脂肪的蓄積受到抑制並降低了血脂含量；飼糧內綠茶副茶粉含量的增加，也可減少產蛋階段雌鳥腹腔內脂肪的蓄積；8%處理組之產蛋雌鳥，無論在飼料換蛋率還是在蛋黃脂肪含量均顯著低於其他處理組者（P < 0.05）。此外餵予雌鳥2%以上的綠茶副茶粉飼糧可以顯著降低其蛋黃中膽固醇的含量。綜合上述之結果，綠茶副茶粉具有抑制日本鵪鶉體內脂肪蓄積與降低蛋黃膽固醇含量的功能。然而為了不影響日本鵪鶉之生長表現與產蛋性能，添加在日本鵪鶉飼糧內的綠茶副茶粉濃度不宜超過2%。

The purpose of this experiment was to investigate the influence of dietary green- tea- byproduct meal levels on the body fat accumulation and yolk cholesterol in Japanese quail. Two stages were conducted. In the beginning, a total of 320 Japanese quails at 1 week of age was allocated randomly into 5 treatments receiving, ad lib, diets containing 0, 1, 2, 4 or 8% of green- tea- byproduct meal, respectively, and growth performance was measured weekly at the first stage. All male Japanese quails were removed at 4 weeks old, and 16 male birds, randomly, per treatment were sampled for analyzing the plasma lipids levels and hepatic fat content. The females, each treatment, were fed continuously with the previous diet until 6 weeks of age and then were switched to a diet with the same treatment but for laying for 10 weeks at the second stage. Laying performance and the weight, fat content and cholesterol level of yolk were measured every 2 weeks. In the end, 16 birds per treatment, randomly, were sampled for analyzing the plasma lipids levels, abdominal fat weight and hepatic fat content. The results showed that body weight at 4 weeks of age and weight gain and feed intake in the first 3 weeks decreased linearly with an increase in the level of dietary green- tea- byproduct meal (p < 0.05). The dietary green- tea- byproduct meal level over 2% depressed the body weight of the females at 6 weeks of age whilst resulted in an increase in the absolute and relative liver weight of the males at 4 weeks of age. A negative linear relationship was observed (p < 0.05) between the dietary levels of green- tea- byproduct meal and the egg weight of the quails from 6 to 16 weeks of age, whilst a negative linear relationship between the green- tea- byproduct meal levels and the hen-day egg production rate or egg mass existed only when the dietary concentration was over 2%. Quadratic relationships were observed between intake, both absolute and relative liver weights, or plasma HDL cholesterol levels of the females from 6 to 16 weeks of age and dietary green- tea- byproduct meal concentrations and individual reflection points located around the 4% of dietary green- tea- byproduct meal. The hepatic fat accumulation and plasma lipid levels of male Japanese quails were inhibited with an increase in the dietary concentration of green- tea- byproduct meal during the growth period, and a similar situation was also observed in abdominal fat accumulation of the laying females. Although the feed conversion rate of the females ingesting 8% of green- tea- byproduct meal was the worst (p < 0.05), their yolk fat content was significantly lower than that of other groups (p < 0.05). In addition, the females ingesting diets containing over 2% of green- tea- byproduct meal showed decreases in the levels of yolk cholesterol. To sum up, green- tea- byproduct meal can inhibit the body fat accumulation of Japanese quail and also decrease the yolk cholesterol levels. However, the dietary concentration of green- tea- byproduct meal should be no more than 2% in order to avoid the negative effects on growth and laying performances.