日粮中添加海藻酸钠对蛋鸡盲肠挥发性脂肪酸含量、pH值及菌群多样性的影响

Effects of adding sodium alginate to the diet on volatile fatty acid content, pH value and microflora diversity in cecum of laying hens

为了研究在蛋鸡日粮中添加海藻酸钠对蛋鸡盲肠挥发性脂肪酸含量、pH值及菌群多样性的影响,试验将600只30周龄体重相近、免疫状况相同的健康海兰褐蛋鸡随机分为4组,分别为对照组、0.8%海藻酸钠添加组、2%海藻酸钠添加组和4%海藻酸钠添加组,对照组仅饲喂基础日粮,0.8%海藻酸钠添加组、2%海藻酸钠添加组和4%海藻酸钠添加组分别饲喂在基础日粮中添加0.8%、2%和4%海藻酸钠的试验日粮,每组5个重复,每个重复30只,进行蛋鸡饲养试验,测定各组盲肠内容物挥发性脂肪酸(乙酸、丙酸、丁酸)含量与pH值,并采用Illumina Miseq测序平台对各组盲肠菌群多样性进行分析。结果表明:与对照组比较,4%海藻酸钠添加组盲肠中乙酸、丙酸、丁酸含量均显著增加(P<0.05),pH值显著降低(P<0.05);2%海藻酸钠添加组盲肠中仅丙酸含量显著增加(P<0.05),乙酸、丁酸含量和pH值均差异不显著(P>0.05);0.8%海藻酸钠添加组盲肠中三种挥发性脂肪酸含量和pH值均差异不显著(P>0.05)。经测序,共获得1 235 390条原始测序片段,其中有效测序片段为893 876条;各组盲肠菌群的OTU数目、ACE指数均差异不显著(P>0.05);4%海藻酸钠添加组的Chao1指数显著低于其他三组(P<0.05);2%海藻酸钠添加组和4%海藻酸钠添加组的Simpson指数显著低于对照组和0.8%海藻酸钠添加组(P<0.05),而4%海藻酸钠添加组的Simpson指数显著低于2%海藻酸钠添加组(P<0.05);各组盲肠菌群相对丰度排名前7位的科均为拟杆菌科、疣微菌科、理研菌科、毛螺菌科、普雷沃氏菌科、福赛坦氏菌科和乳杆菌科,其中拟杆菌科、疣微菌科与理研菌科是蛋鸡盲肠优势菌科;与对照组比较,0.8%海藻酸钠添加组、2%海藻酸钠添加组和4%海藻酸钠添加组盲肠中乳酸杆菌的相对丰度均极显著提高(P<0.01),分别提高了208.32%、310.11%和763.78%。说明在蛋鸡日粮中添加海藻酸钠可以有效增加蛋鸡盲肠挥发性脂肪酸含量,降低pH值,改善蛋鸡盲肠菌群多样性,对蛋鸡肠道健康产生有益影响。

In order to study the effects of adding sodium alginate to the laying hen diet on volatile fatty acid content, pH value and flora diversity in the laying hen cecum, 600 30-week-old healthy Hyline brown laying hens with similar body weight and immune status were randomly divided into 4 groups: control group, 0.8% sodium alginate supplemental group, 2% sodium alginate supplemental group and 4% sodium alginate supplemental group. The hens in the control group were fed a basal diet. The hens in the sodium alginate groups were fed basal diets supplemented with 0.8%, 2% and 4% sodium alginate, respectively. There were 5 replicates in each group and 30 laying hens in each replicate. The contents of volatile fatty acids(acetic acid, propionic acid and butyric acid) and pH values in cecum contents of each group were determined, and the diversity of cecum microflora in each group was analyzed by Illumina Miseq sequencing platform. The results showed as follows: compared with the control group, the contents of acetic acid, propionic acid and butyric acid in caecal content in the 4% sodium alginate group were significantly increased(P<0.05), and the pH value was significantly decreased(P<0.05);only propionic acid content in 2% sodium alginate supplemental group was significantly increased(P<0.05), but the contents of acetate and butyric acid and the pH value were not significantly different(P>0.05);there were no significant differences in the contents of three volatile fatty acids and the pH value in cecum content of Hyline brown laying hens in the 0.8% sodium alginate group(P>0.05).A total of 1 235 390 original sequences were obtained by sequencing. Among them, 893 876 were effective. There were no significant differences in OTU number and ACE index of cecal microflora among all groups(P>0.05). The Chao1 index in the 4% group was significantly lower than that in the other three groups(P<0.05). The Simpson index in the 2% and 4% sodium alginate supplemental groups was significantly lower than that in the control group and 0.8% sodium alginate supplemental group(P<0.05), while the Simpson index in the 4% sodium alginate supplemental group was significantly lower than that in the 2% sodium alginate supplemental group(P<0.05). The top 7 families in relative abundance of cecal contents in three groups were Bacteroideaceae, Verrucobacteriaceae, Riesearchaceae, Pilonospiraceae, Prevotellaceae, Forsetanaceae and Lactobacillus, among which Bacteroideaceae, Verrucobacteriaceae and Riesearchaceae were the dominant bacteroideaceae of laying hens. Compared with the control group, the abundance of lactobacillus in cecum in the 0.8% sodium alginate supplemental group, 2% sodium alginate supplemental group and 4% sodium alginate supplemental group was significantly increased by 208.32%, 310.11% and 763.78%, respectively(P<0.01). These results indicated that sodium alginate added to the diet of laying hens could effectively increase the contents of volatile fatty acids in cecal contents of laying hens, reduce the pH value, improve intestinal microflora diversity of laying hens, and have beneficial effects on intestinal health of laying hens.