Effects Of Different Ratios Of Linseed Oil And Palm Oil On Rumen Fermentation And Fatty Acid Composition Of Cashmere Goats

This paper mainly studies the effects of different ratios of linseed oil and palm oil on the rumen fermentation and fatty acid composition of cashmere goats.The results provide theoretical support for improving the fatty acid composition of mutton in cashmere goats by nutrition profile.The test is divided into two parts:an in vitro test(test 1 and test 2)and an in vivo feeding test(test 3).Test 1 mainly selected initially the ratio of linseed oil to palm oil.It was conducted using a single factor completely randomized design and divided into five treatments according to linseed oil:palm oil,namely 0:10(Group I),4:6(Group?),5:5(Group III),6:4(Group IV)and 10:0(Group V),with 6 replicates each treatment.The ratio of concentrate to forage in substrate diet was 50:50,and the amount of oil added accounted for 2%of the substrate diet.Adult Arbas white cashmere goats were used as rumen fluid donor.In the experimental period,the rumen fluid was collected before morning feeding by oral cavity for in vitro culture,and the rumen fermentation related indexes at 3h,6h,9h,12h and 24h and fatty acid composition at 24h were measured.Test 2 selected and optimized futher the ratio of the linseed oil to palm oil based on the first test.The single factor completely randomized trial design was adopted and divided into six treatments according to linseed oil:palm oil,namely 5:5(Group I),6:4(Group II),7:3(Group III),8:2(Group IV),9:1(Group V)and 10:0(Group VI),with 6 replicates each treatment,and the others are the same as test one.Experiment 3 mainly used the in vivo method to study the effect of the mixed addition of linseed oil and palm oil on the rumen fermentation and fatty acid composition of cashmere goats.Using the 3x3 complete Latin square test design,12 adult healthy Arbas white cashmere goats with similar body weights were used.The goats were randomly divided into three groups:palm oil group(Group I),mixed oil group(Group II)and linseed oil group(Group III),with 4 replicates in each group.The ratio of linseed oil to palm oil in the mixed oil group was 6:4 according to test 2.The ratio of concentrate to forage in diet is 50:50,and the amount of oil added is 2%of the total diet.Each period trial lasted for 28 days,including 7d pre-feeding period and 21d formal test period.On the last 2 days of the formal test period,the rumen fluid was collected twice in the oral cavity at Oh before morning feeding and 6h after morning feeding,and the relevant indicators were determined.The results of experiment 1 showed that compared with the linseed oil group,the NH3-N concentration,the number of protozoa and the gas production of in vitro rumen culture solution of the mixed oil group decreased,and the BCP concentration and the VFA concentration increased.C18:3n-3 and n-3PUFA content reached a level similar to that of linseed oil alone,and is significantly higher than that of the palm oil group,especially in the group IV added in the ratio of 6:4.Considering many indicators,the ratio of linseed oil to palm oil with 6:4 had better effect.The results of experiment 2 showed that compared with the linseed oil group,the concentration of BCP and TVFA in the mixed oil group increased,the number of protozoa,NH3-N concentration and A/P decreased;and the C18:3n-3 and n-3PUFA content of in vitro rumen culture fluid was increased.With the incresing proportion of linseed oil in the mixed oil group,the concentration of C18:1c9 was decreased gradually,especially in the mixed oil group with a ratio of 9:1 and linseed oil group,and significantly lower than the 5:5 mixed oil groups.According to these indicators,the linseed oil to palm oil ratio with 6:4 showed the better effect.The results of experiment 3 showed that the number of protozoa,NH3-N concentration and acetic acid to propionic acid were decreased significantly and BCP concentration was increased significantly in rumen fluid in mixed oil group(linseed oil:palm oil,6:4).C18:3n-3 and n-3PUFA content in rumen was significantly higher than that of the palm oil group,but there was no significant difference with the linseed oil group.In summary,this study found that dietary supplementation with a combination of linseed and palm oils in a ratio of 6:4 improved the rumen fermentation function of cashmere goats and increased C18:3n-3 content in rumen fluids compared to palm oil alone,and n-3PUFA content reached a level similar to that of linseed oil alone.The mixed addition of linseed oil and palm oil showed the better effect than linseed oil or palm oil alone.