体外培养条件下不同长链脂肪酸对山羊瘤胃原虫群体结构和原虫吞噬细菌循环的影响

摘要

本试验旨在研究体外培养条件下不同长链脂肪酸对山羊瘤胃原虫群体结构和原虫吞噬细菌循环的影响.试验选取6种不同不饱和度的长链脂肪酸[分别为硬脂酸(A组)、油酸(B组)、亚油酸(C组)、α-亚麻油酸(D组)、花生四烯酸(E组)、二十碳五烯酸(F组),不饱和键个数从0~5依次递增],各脂肪酸的添加水平为底物的3%,进行体外培养.在体外培养10 h后测定原虫吞噬细菌速率,在体外培养24 h后测定细菌、原虫密度以及细菌蛋白质、原虫蛋白质含量.结果表明:除F组头毛虫属(Ophryoscolecinae)比例显著高于B和D组(P<0.05)外,不同长链脂肪酸的添加对原虫中厚毛虫属(Dasytricharuminantium)、内纤毛虫属(Entodinium)、双毛虫属(Diplodiniinae)、等毛虫属(Isotrichidae)、前毛虫属(Epidinium)比例的影响均不显著(P>0.05).原虫密度以A组最高,并显著高于B组(P<0.05);细菌密度以D组最高,并显著高于A、B、E、F组(P<0.05).原虫吞噬细菌速率A~F组依次为244.50、236.51、229.60、189.04、200.51、174.24 cells/(cell·h);另外,以D组的细菌周转率(0.68%)最低,且其细菌周转时间(146.92 h)最长.所估算的细菌蛋白质循环量以D[126.75 mg/(d·头)]和F组[131.63 mg/(d·头)]相对较低.因此,在本试验基础上认为,体外培养条件下α-亚麻油酸抑制山羊瘤胃原虫吞噬细菌效果较好.%This experiment was conducted to investigate the effects of different long-chain fatty acids on proto-zoal community structure and bacterial recycling due to protozoa engulfment of goat rumen in vitro. Six long-chain fatty acids with different saturations were selected, they were stearic acid ( group A) , oleic acid ( group B) , linoleic acid ( group C) , α-linoleic acid ( group D) , arachidonic acid ( group E) and eicosapentaenoic acid ( group F) , respectively, and the number of unsaturated bond of them was orderly increased from 0 to 5. The fatty acids above were used at a level of 3% in the substrate to perform the in vitro culture. The protozoal engulfing bacteria rate was assayed at 10 h of the in vitro cultured and the densities of protozoal and bacterial and the contents of the protozoal protein and bacterial protein were measured at 24 h of the in vitro culture. The results showed that, except the percentage of Ophryoscolecinae in group F was significantly higher than that in groups B and D ( P<0.05) , adding different long-chain fatty acids had no significant effects on the percentages of Dasytricharuminantium, Entodinium, Diplodiniinae, Isotrichidae and Epidinium ( P>0.05) . The protozoal density was the highest in group A which was significantly higher than that in group B ( P<0.05); while the bacterial density in group D was the highest and significantly higher than at in groups A, B, E and F ( P<0.05). The bacteria engulfing rate of protozoa in 5 groups was 244. 50 ( group A), 236. 51 ( group B), 229.60 ( group C) , 189.04 ( group D) , 200.51 ( group E) , 174.24 cells/( cell·h) ( group F) , respective-ly. Additionally, the bacteria recycling rate was the lowest in group D with the longest bacterial cell recycling time ( 146. 92 h) . It was further calculated that, the bacterial protein recycling amounts were comparatively lower in groups D [126.75 mg/(d·head)] and F [131.63 mg/(d·head)]. Base on this experiment, it is therefore considered that α-linoleic acid has better inhibitory effect on the bacterial recycling due to protozoa engulfment of goat rumen in vitro.