Effects Of Dietary Addition Of Soybean Lecithin On Ruminal Metabolism And Microbial Diverisity In Sheep

Four Chinese Merino male sheep fitted with rumen fistula were used in a4×4Latin square design to study effects of dietary addition of0,10,20or40g/d soybean lecithin on feed intake, ruminal metabolism, microbial diverisity and nutrients digestion. Results showed that intake of wheat straw, rumen fluid pH and the concentration of volatile fatty acids were not affected by soybean lecithin supplementation (P>0.05), but the concentration of ruminal ammonia-N trended to increase. Compared with the control group, the intake of ether extract were respectively increased40.82%,83.91%and160.04%(P<0.05), and the intake of phosphorus were respectively increased11.82%,24.55%and44.55%(P<0.05). The activities of β-1,4-exoglucanase were increased62.45%and63.85%(P<0.05), and the specific activities of β-1,4-exoglucanase increased60.54%and68.35%by supplementation of20g/d and40g/d soybean lecithin respectively(P<0.05); Activity of β-glucosidase was reduced8.04%by20g/d soybean lecithin supplementation, while that was increased13.53%by40g/d soybean lecithin supplementation (P<0.05), and specific activities of β-glucosidase was increased27.73%by40g/d soybean lecithin supplementation (P<0.05); The activity and specific activities of β-1,4-endocellulase and xylanase were not affected by soybean lecithin addition(P>0.05); According to the results of PCR-DGGE, rumen microbial population structure and diversity were changed by soybean lecithin addition. DNA copy numbers of fungi in the rumen contents were increased (P<0.05), and that of total bacterial trended to increase, but the count numbers of protozoa were not affected by soybean lecithin supplementation (P>0.05). Compared with the control group, DNA copy numbers of fungi in the rumen contents were increased66.22%,75.33%and52.56%by supplementation of10g/d,20g/d and40g/d soybean lecithin respectively(P<0.05), and that of total bacterial was increased20.23%by lOg/d soybean lecithin supplementation(P<0.05). Compared with the control group, the digestion of ether extract were respectively increased51.69%,110.07%and233.78%(P<0.05), and the apparent digestibility were respectively increased16.02%,22.97%and38.11%(P<0.05), the apparent digestibility of cellulose was increased30.25%(P<0.05) by supplementation of20g/d soybean lecithin; and the digestion and apparent digestibility of other nutrients trended to increase in the20g/d group.The results implied that soybean lecithin could improve activity of β-1,4-exoglucanase, increase the numbers of ruminal bacteria and fungi, and increase the apparent digestibility of cellulose, and effect the rumen digestion and metabolism.