Effect Of Dietary FNDF Sources And Levels On The Performances And Rumen Function Of Finishing Hu Sheep

Dietary fiber can effectively stimulate animal chewing and ruminating,maintain normal rumen pH,and reduce the risk of ruminal acidosis caused by excessive intake of concentrate.Dietary fiber content affects the nutrient concentration of the diet and thus affects DMI and feed efficiency.Therefore,how to balance the feed efficiency and rumen health is an urgent problem for the aquaculture industry.The goal of this study was to investigate the effects of dietary FNDF sources and levels on the performances,nutrient digestion and rumen microbial composition of the fattening Hu sheep and provided a theoretical basis for the utilization of straw in improving the health and efficient production of fattening sheep.In this experiment,90 of healthy Hu male lambs,2-months-old,with a similar body weight of(26.12±0.25 kg)were divided into 6 treatments,with 15 replicates in each treatment and 1 lambs per relicate in a 2×3 factor design.The experiment factor were FNDF sources(corn straw,wheat straw)and FNDF levels(7%,12%,17%).The experiment lasted 84 days,including a 14 days of transition period,7 days of prefeeding period and 63 days of trial period.The effects of FNDF sources and levels on performance,nutrient digestion,rumen microbial composition and serum biochemical parameters of finishing Hu sheep were studied.The results are as follows:1.The FNDF source had no effect on the growth performance and nutrient digestibility of the fattening Hu lamb sheep(P>0.05).The N retention rate of the corn straw group was significantly higher than the wheat straw group(P<0.05).The high FNDF level finishing Hu lamb’s in 1-21 d and whole trial period body weight,ADG were significantly lower than medium and low FNDF level group(P<0.05)and F:G was significantly higher than lower than medium and low FNDF(P<0.05).Sheep in high FNDF group have lower DM,OM,NDF,N digestibility than the medium and low FNDF level groups(P<0.05),N in feces was higher than the other groups(P<0.05).The sources and levels of FNDF had an interaction with DMI,ADG and NDF in the fattening Hu sheep for 42-63 d(P<0.05).2.The FNDF sources had no effect on the TVFA concentration,VFA proportions of the fattening Hu sheep(P>0.05).The number of fibrobacter succinogenes and sucininimonas ruminicola in the corn straw group was significantly higher than the wheat straw group(P<0.05).The high FNDF level group’s he ratio of acetate and A/P were significantly higher than medium and low FNDF level group(P<0.05)and the ratio of propionate and valeric acid was significantly lower than the medium and low FNDF level group(P<0.05).3.The FNDF source on serum biochemical indexes of the fattening Hu sheep is not significant(P>0.05);the high FNDF level group’s carcass weight was lower than the middle and low FNDF levels group(P<0.05).With the improved of FNDF level,the total cholesterol content in Hu sheep serum decreased significantly(P<0.05).4.The FNDF sources on the concentration of TFA and muscle fatty acid composition of fattening Hu sheep is not significant(P>0.05).The ratios of C17:0,C17:1,C18:1 trans,C18:1 cis-11,C18:2 n-6c,C18:3n-3 in muscle of the high FNDF level was significantly lower than medium and low FNDF level groups(P<0.05);the ratios of C18:0,C18:1 cis-9,C18:1 cis-12,C18:2 n-6t significantly higher than medium and low FNDF level group(P<0.05).FNDF sources and levels have significant interactions with C18:3 n-3 in muscleIn summary,the sources of straw on the performances,rumen VFA,muscle fatty acid compositions and serum biochemical indexes of the fattening hu sheep is not significant.With FNDF level decreased,improved the digestibility of nutrients in the fattening Hu sheep,the number of cellulolytic bacteria reduced,promoted the synthesis of propionate and improved the feed efficiency and ADG,and the suitable FNDF level of the diet is 7-12% in this experiment.With the level of dietary FNDF decreased,increased the ratio of C17:0,C17:0,weaken the biohydrogenation function of fatty acids,and increased the ratio of unsaturated fatty acids C18:2 n-6 c,C18:3 n-3,C18:1 cis-11,C18:1.