飼料中添加海藻糖對泌乳羊之生產表現與抗氧化能力之影響

Effect of Trehalose Supplementation on Production Performance and Antioxidant Capacity of Dairy Goats

陳俞瑾(Yu-Jin Chen)

指導教授 ： 徐濟泰

國立臺灣大學/生物資源暨農學院/動物科學技術學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.01819

摘要

海藻糖最早由科學家在黑麥的麥角水溶液中發現，外觀為無色具有甜味的晶體，為一種天然的雙醣，由兩個葡萄糖分子以α,α-1,1醣苷鍵縮合的方式鍵結而成，廣泛存在於自然界中，植物、蕈類、細菌、真菌以及無脊椎動物中均可以發現。經研究發現海藻糖具有抗氧化特性，尤其可以抑制脂質過氧化，在環境壓力中藉此穩定組成細胞膜的不飽和脂肪酸，以維持細胞正常生理功能；此類環境壓力包含熱緊迫，已有研究指出，生物體內活性氧物質與抗氧化系統若失衡，則會造成氧化壓力的發生，可能危及動物健康並影響經濟動物的生產表現與產品品質。在台灣夏季，生產型經濟動物常常會面臨到熱緊迫所帶來之生產表現下降的情形，不僅是泌乳牛，泌乳羊同樣會遭受到熱緊迫，而熱緊迫也會使動物體內氧化壓力上升。本試驗於泌乳羊飼糧中添加1%海藻糖與1%麥芽糖，比較海藻糖是否能改善動物生產表現、降低熱緊迫以及提高抗氧化能力。
本試驗選用9隻已經過泌乳高峰之阿爾拜因山羊（Alpine），進行3x3拉丁方試驗設計，依乳量平均分配成3個處理組（對照組、1% 海藻糖添加組、1% 麥芽糖添加組），以代謝架進行個別飼養試驗。拉丁方的每個試驗期包含16天適應期與5天採樣期，於採樣期間收集全糞、全尿、剩料、血液、羊乳與瘤胃液樣品，並紀錄試驗場所溫度與濕度，計算THI作為是否處於熱緊迫環境的指標。
分析結果顯示，試驗期間之環境溫濕度指數可能未對羊隻帶來顯著的熱緊迫。泌乳羊之乾物質採食量、產乳量、乳成分組成、血液生化值、瘤胃液酸鹼值、揮發性脂肪酸濃度與原蟲數目表現上，三個處理組間並無顯著差異。控制組有顯著較麥芽糖組高的非結構性碳水化合物採食量。在消化率方面，添加1%麥芽糖有顯著較低的有機質消化率；乳脂肪酸組成分析中，添加海藻糖與麥芽糖可顯著提高羊乳中的短鏈脂肪酸組成。再者，海藻糖可以較控制組顯著提高羊乳中亞麻油酸（C18:2）含量36%與共軛亞麻油酸（CLA）含量11%，並且較麥芽糖組有顯著較高的 α-次亞麻油酸（C18:3n3）含量；在抗氧化能力分析中，泌乳羊血漿與瘤胃液之超氧歧化酶與硫巴比妥酸值無顯著差異。DPPH自由基清除能力結果顯示，三個處理組之瘤胃液與血漿無差異，而羊乳中海藻糖有最高清除能力並顯著高於麥芽糖組。
綜觀上述試驗結果，可能由於環境溫濕度指數與飼糧配方因素，導致泌乳羊並未處於顯著的熱緊迫狀態，雖然沒有顯著改善效果，但餵飼海藻糖對於受熱緊迫泌乳羊之生產與生理表現並無負面影響，且可以有效改善羊乳的自由基清除能力與增加長鏈脂肪酸含量進而提升羊乳營養價值之潛力。

關鍵字

海藻糖 ； 麥芽糖 ； 氧化壓力 ； 抗氧化能力 ； 泌乳羊

並列摘要

Trehalose, a neutral disaccharide composed of two molecules of glucose linked by an α,α-1,1 glucosidic linkage. It is used widely, particularly as food additive, cosmetic ingredient, and antioxidant. Oxidative stress leads to aging and disease in animals and is caused by an imbalance between the production of reactive oxygen species (ROS) and antioxidant activity. In Taiwan, both dairy cows and goats will suffer from heat stress during the summer, and this condition will affect their health and milk production performance. So, we hypothesized that dietary trehalose supplementation might protect against oxidative stress in dairy goats, thereby resulting in milk with low lipid peroxide and high antioxidant content.
Nine Alpine dairy goats housed separately in individual pens were divided into 3 groups, with each group receiving a different dietary treatment (control diet, 1% trehalose-supplemented diet, and 1% maltose-supplemented diet) following a 3×3 Latin square design. During the experiment period, we collected feces, refusals, urine, milk, blood, and rumen fluid samples. Then we analyzed nutrients digestibility, blood biochemical value, milk and milk fatty acid composition, rumen fluid volatile fatty acids (VFAs) and rumen protozoa number, and antioxidant content in blood, milk, and rumen fluid.
There was no significant difference in dry matter intake, milk composition and production, blood biochemistry parameters, rumen fluid pH, VFAs concentrate and protozoa number among three groups. In milk fatty acids composition, the trehalose group has higher C18:2 and conjugated linoleic acid (CLA) contents than the control group (p<0.05). Antioxidant activities were estimated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, relative superoxide dismutase (SOD) activity and thiobarbituric acid reactive substances (TBARS) assay, respectively. The results show that the trehalose treatment has higher DPPH scavenging activity in milk than the maltose group (P<0.05) , but has no difference compared to the control group. Additionally, there is no difference on SOD or TBARS among the three groups.
Maybe because of the temperature-humidity index and diet formula, the experimental conditions can’t lead to effective heat-stress for these dairy goats. Based on the current results, our research demonstrated that trehalose supplementation in diet of dairy goats will change the milk fatty acid composition to increase C18:2, and CLA content compared to the control group. Besides, trehalose treatment has greater goat milk DPPH scavenging activity than the maltose treatment. These results suggest that adding trahalose in the diet of dairy goats might have positive effects potentially.

並列關鍵字

trehalose ； maltose ； oxidative stress ； antioxidant capacity ； dairy goats

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