Effects Of Linseed Diet Feeding Time On Fattening Performance And Meat Quality Of Lambs

In this study,we added linseed diet at different time periods during the fattening of lambs,the effects on the performance,slaughter performance,meat quality,muscle and rumen composition of fatty acids were explored,which provided the theoretical basis for the suitable feeding time of linseed diet.100 similar weight(25 + 0.58 kg),health,same genetic background,2.5 months weaning of Hu lambs were selected and divided into 4 treatment groups were 0 days(control group),14 BS group(the linseed diet was fed 14 days before slaughter),28 BS group(the linseed diet was fed 28 days before slaughter)and 42 BS group(the linseed diet was fed 42 days before slaughter),each treatment has five replicates with fixe sheep per replicate,the transition period is 14 days,the pre-trial period is 7 days and the test period is 42 days.The result are as follows:1.The results showed that the linseed diet feeding time had significant effect on the performance and slaughter performance of lambs at different times(control?14BS group?28BS group and 42 BS group)(P <0.05),42 BS group compared with control significantly increased the daily gain of lamb(P = 0.036),the final body weight was the lowest at 14 BS group,significantly lower than 42 BS group(P=0.045),42 BS group feed weight ratio was significantly lower than 14 BS group(P=0.028),carcass weight at control and 14 BS group were significantly lower than 42BS(P=0.021),the live weight was the highest at 42 BS,significantly higher than 14 BS group(P = 0.015);The addition of 8% linseed group had no effect on the digestibility of DM,OM and ADF(P <0.05),but the linseed group increased the fecal nitrogen excretion,there was a tendency to reduce the digestion of N(P=0.068).2.14 BS group acetic acid proportion of rumen was significantly higher than control(P = 0.031),Propionic acid was the highest at control significantly higher than other treatment groups(P = 0.001),A / P was the lowest at control significantly lower than other treatment groups,TVFAs at 14 BS group and42 BS group were significantly lower than control(P = 0.041);42BS group compared with control significantly increased the relative abundance of Butyrivibrio fibrisolwens(P=0.009),42 BS group compared with control significantly reduced the relative abundance of Clostridium proteoclasticum(P=0.031).3.The contents of C15:0,C17:0,C18:0 and SFA in rumen contents were significantly decreased with the incresng feeding time of linseed diet(P<0.05),the contents of trans-11 C18:1,cis-9 C18:1,CAL,n-3 PUFA and MUFA in linseed group(14 BS group,28 BS group and 42 BS group)were significantly higher than control(P<0.05),the content of CLA in 14 BS group,28 BS group and 42 BS group were increased 33.23%,74.77% and 63.36% than control,respectively(P=0.025).4.The contents of C14:0,C15:0 and C16:0 in the muscle of lambs and n-6 / n-3 value were significantly decreased with the incresng feeding time of linseed diet(P<0.05),42 BS group the content of trans-11 C18:1,C16:1,CLA,ALA,C20:3n-3,EPAand DHA were significantly higher than control(P<0.05),the content of CLA in 14 BS group,28 BS group and 42 BS group were increased 76.52%,276.22% and 876.11% than control,respectively(P=0.016),the content of n-3PUFA in 14 BS group,28 BS group and 42 BS group were increased 115.79%,252.86% and 497.69% than control,respectively(P=0.003).As above,the daily gain of lambs were increased with the incresng feeding time of linseed diet,the feed conversion ratio was reduced,the performance and meat quality of lambs were improved;The content of CLA and n-3PUFA in muscle of fattening lambs was significantly increased by feeding linseed diet at 28 days and 42 days before slaughter,the n-6 / n-3 value was reduced at 28 days and 42 days before slaughter,the fatty acids composition of muscle were improved.