柠条对滩羊肉品质、胃肠道挥发性脂肪酸及其菌群的影响

Effect of Caragana korshinskii Kom.on Meat Quality of Adipose Tissue,Volatile Fatty Acids and the Microbiota in Gastrointestinal Tract for Tan Sheep

为探索日粮中添加柠条影响瘤胃、结肠内微生物生成的挥发性脂肪酸水平,进而调节滩羊肉品质、脂肪组织中主要脂肪酸含量的作用,本研究选取12只四月龄滩羊母羔随机分为两组,NC组饲喂30%精料及70%苜蓿颗粒,CK组为10%柠条替代等量苜蓿。预饲期10 d,正试期60 d。饲喂期结束屠宰时取其背最长肌、股四头肌、皮下脂肪,瘤胃、结肠内容物,利用16S rRNA测序技术、气相色谱-质谱联用技术等对滩羊瘤胃、结肠内菌群、脂肪组织的脂肪酸含量及肌肉理化特性进行测定。结果表明,饲喂柠条可导致滩羊股四头肌的压榨损失有提高的趋势,系水力和熟肉率有所下降;但饱和脂肪酸有降低的趋势,不饱和脂肪酸有提高的趋势;皮下脂肪中的软脂酸含量显著降低(P<0.05);瘤胃内丁酸和结肠内乙酸的浓度显著降低(P<0.05),结肠内异丁酸和异戊酸等支链脂肪酸水平极显著提高(P<0.01)。斯皮尔曼相关性分析显示,瘤胃内5-7N15菌属和YRC22菌属均与丁酸含量趋向正相关,而结肠内密螺旋体属与乙酸含量趋向正相关,但与异丁酸含量趋向负相关(0.05<P<0.1);结肠内异丁酸含量与股四头肌的熟肉率、系水力和压榨损失分别呈高度负相关和正相关,乙酸亦与背最长肌pH呈负相关关系。综上,柠条部分替代苜蓿饲喂滩羊,可以提高脂肪组织中不饱和脂肪酸含量,可作为反刍动物的粗饲料加以开发利用。

To explore the effect of Caragana korshinskii Kom.(CK)on meat quality and the main fatty acids of adipose tissue,which were supposed to be modulated by the level of volatile fatty acids from the microbiota of rumen and colon in sheep,twelve Tan ewe lambs(4-month-old)were randomly divided into two groups,NC was fed with 30%concentrate and 70%alfalfa,while CK with 10%CK instead of equivalent alfalfa.After 10 days of pre-trial and 60 days of feeding trial,the lambs were slaughtered and sampled with M.longissimus dorsi,quadriceps femoris,subcutaneous fat,and the contents of rumen and colon collection.Then the analyzing was carried out aimed to determine the characters of meat physical and chemical properties as usual method,the microbiota of gastrointestinal tract by 16S rRNA sequencing,and fatty acid contents either from subcutaneous adipose tissue or from rumen and colon by gas chromatography-mass spectrometry.The results showed that feeding CK to Tan sheep could tend to increase mill loss,decrease water holding capacity and cooked meat percentage of quadriceps femoris.It also had the tendency effect to decrease saturated fatty acid and increase unsaturated fatty acid content in the meat.Furthermore,feeding CK could decrease the content of palmitic acid in subcutaneous adipose tissue significantly(P<0.05).Besides,the concentrations of butyric acid in rumen and acetic acid in colon decreased significantly(P<0.05),while the levels of branched chain fatty acids such as iso-butyric acid and iso-valeric acid in colon increased significantly(P<0.01).Through correlation analysis by Spearman method,both 5-7N15 and YRC22 in rumen genera tended to positively correlated with butyric acid concentration,while Treponema in colon genera tended to positively correlated with acetic acid content,but negatively correlated with the level of iso-butyric acid(0.05<P<0.1).In colon,iso-butyric acid was high inversely and positively correlated with the cooked meat percentage,water holding capacity and mill loss of quadriceps femoris,and acetic acid was negatively correlated with the pH value of M.longissimus dorsi.In conclusion,feeding CK to Tan sheep with partly instead of alfalfa could improve unsaturated fatty acid contents of adipose tissue,and then it could be developed as ruminant forage for utilization.