液化澱粉芽孢桿菌和啤酒酵母對紅羽土雞腸道菌相之影響

在台灣有色肉雞中紅羽土雞是飼料效率較好的品種，但因飼料換肉率與整齊度仍不及於白肉雞。本研究目的希望探討飼料中添加混合液化澱粉芽孢桿菌和啤酒酵母對於紅羽土雞生長性能之影響，及其可能的機制。在田間試驗中，將18,000隻的紅羽母雞隨機分為兩組，基礎飼糧（對照組）和基礎飼糧添加0.05%液化澱粉芽孢桿菌與0.05%啤酒酵母菌（各5×106 CFU/kg）（益生菌組），實驗為期11週。與對照組相比，益生菌組能顯著增加11週紅羽土雞的體增重，整體FCR更優於對照組。評估腸道型態，與對照組相比，益生菌組能增加11週齡雞隻迴腸、9週齡雞隻空腸的絨毛長度以及11週齡雞隻迴腸、7和11週齡雞隻空腸絨毛長度和腺窩深度比。利用總體基因體學分析腸道微生物菌相組成，與對照組相比，益生菌組9週和11週齡雞隻盲腸中厚壁菌門/擬桿菌門比值（F/B ratio）有顯著增加（p < 0.05）。α多樣性結果顯示各時間點與對照組相比，益生菌組並無顯著增加微生物群落的豐富性和多樣性（p > 0.05）。β多樣性結果顯示各時間點對照組和益生菌組菌相組成結構有顯著性差異（p < 0.05），尤其在7週齡差異最大。透過LEfSe找出7週齡兩組間的優勢菌種，益生菌組以Bacteroides菌屬和Olsenella菌屬為主；並在益生菌組各週相比，能顯著增加盲腸中產短鏈脂肪酸菌群的豐富度，如4週齡Faecalibacterium菌屬，7週齡Alistpes菌屬、 Megamonas菌屬和Olsenella菌屬，9週齡Bacteroides菌屬和Ruminococcus torques group菌屬，11週齡Prevotellaceae菌科等優勢菌種。透過MetagenomeSeq分析，結果顯示益生菌組能增加盲腸中有助於家禽生長表現與體重增加相關益菌屬（科），如Lactobacillus菌屬、Akkermansiaceae菌科和Lachnospiraceae菌科，並減少盲腸中影響家禽生長表現之伺機性菌屬，如Escherichia/Shigella菌屬、Staphylococcus菌屬和Campylobacter jejuni。Tax4Fun功能預測顯示與對照組比，益生菌組各週齡碳水化合物代謝、胺基酸代謝、脂質代謝、能量代謝、核甘酸代謝和聚醣生物合成與代謝相關的功能途徑顯著增加，尤其在以雞隻7週齡時具有多種多樣的代謝潛力。綜合以上，飼料中添加液化澱粉芽孢桿菌和啤酒酵母能使紅羽土雞之生長表現更優於對照組，其可歸因於增加盲腸中與體重增加相關之益菌屬豐度、有減少腸道之伺機性菌屬潛力、並增加產短鏈脂肪酸的菌群和激發多種代謝路徑，進一步促使紅羽土雞對於營養吸收及利用效能更佳，提升雞隻飼料換肉率。

關鍵字

液化澱粉芽孢桿菌；啤酒酵母；紅羽土雞；總體基因體學；腸道微生物

並列摘要

Red-feathered Taiwan country chickens have been long-term selected for feed efficiency and are the best breeders of colored broilers in Taiwan. The competitiveness of red-feathered Taiwan country chickens is gradually decline due to low uniformity, poor feed conversion rate and the impact of instant food culture versus traditional Chinese culture. To assess the effects of diet mixture with Bacillus amyloliquefaciens（BA）and Saccharomyces cerevisiae（SC）to red-feathered Taiwan country chickens. In the field study, eighteen thousand one-day old chickens were randomly divided into 2 groups, including basal diet（control group）and basal diet mixed 0.05% BA（5×106 CFU/kg） and 0.05% SC（5×106 CFU/kg）（probiotic group）with 11 weeks experience period. The body weight in probiotic group was significantly higher（p < 0.05）than the control and FCR was lower than the control on 11 weeks. Regarding to morphology, compared to control group, probiotic group had increased ileum villus height and villus height / crypt depth at the 11th week; jejunum increased villus height at the 9th week and villus height / crypt depth at the 7th 11th week. By metagenomics analysis, F/B ratio was higher in the probiotic group than in the control group at the 9th and 11th week. There were no significant differences between same age of probiotic and control group in α diversity. But β diversity showed difference（p < 0.05）between probiotic to control group especially at week 7th. LEfSe identified biomarkers of SCFAs bacterial declared that probiotic group at the 7th week had richer Bacteroides and Olsenella than control group. Increasing the richness in probiotic group such as Faecalibacterium at the 4th week, Alistpes、Megamonas and Olsenella at the 7th week, Bacteroides and Ruminococcus torques group at the 9th week, Prevotellaceae at the 11th week. By metagenomeSeq, the probiotic group increase abundance of several weight related bacterial groups such as Lactobacillus、Akkermansia and Lachnospiraceae, and decrease the zoonotic opportunistic bacteria such as Escherichia/Shigella, Staphylococcus and Campylobacter jejuni in cecum. Tax4Fun analysis showed that probiotic supplementation, especially at the 7th week, significantly affected the metabolism pathways associated with carbohydrate metabolism, amino acid metabolism, nucleotide metabolism, lipid metabolism, glycan biosynthesis and metabolism. Take all above results, the combination of BA and SC in feed offered red-feathered Taiwan country chickens better performance which contributed from raising abundance of several weight improving bacterial groups in cecum and decreasing opportunistic bacteria. It also increased the relative abundance of genera associated production of SCFAs, which activated functional pathways associated with efficient nutrition and energy metabolism. The study demonstrated that the supplementation of BA and SC could be an effective growth promoter to accelerate the chickens’ growth.