Effect Of Ratio Of Structural And Nonstructural Carbohydrates In Diets On Fatty Acid Profiles In Milk Fat From Lactating Ewe

Three experiments were conducted to research the effect of Ratio of Structural and Nonstructural Carbohydrates in Diets on fatty acid profiles in milk fat from lactating ewe.Experiment 1. The objective of this study was to investigate the effect of 4 different proportions of sheep dietary structural and nonstructural carbohydrates on rumen fermentation in vitro, and 4 proportions of structural and nonstructural carbohydrate were 1.84(Group A),1.51(Group B),0.92(Group C)and 0.71(Group D)respectively. The results showed that there was significant difference of maxture gas production(P<0.05)among the designed ranges of SC:NSC, and that gas production veloc was inverse correlation(R=-0.9372)with SC:NSC.The degradability of DM increased significantly(P<0.05),meanwhile both NDF and ADF were facilitated with the decrease of SC:NSC. Rumen ammonia-N concentration which increased with the decrease of SC:NSC was significan(tP<0.05)difference amongst 0 to 48h, besides that pH value and carboxymethylcellulase(CMCase)activity maintained the relative stability(P>0.05). From 0 to 24h , xylanase activity which was positive correlation(R=+0.9741)with SC:NSC decreased significantly (P<0.05).General volatile fatty acid concentration which was influenced by SC:NSC was significant(P<0.05)difference, but the mole percentage of acetate, propionate and butyrate were no significant(P>0.05)difference. In the ratio of acetate to propionate would be depressed following the SC:NSC degression. The group feedstuff of C(SC:NSC=0.92)was the most effective in the utilization according to the synthesis of each target in the experiments.Experiment 2. The objective of this study was to investigate the effect of 4 different proportions of sheep dietary structural and nonstructural carbohydrates on rumen fat hydrolysis and Hydrogenated fatty acid extent by thin-layer chromatography(TLC)and gas chromatographic technique, and 4 proportions of structural and nonstructural carbohydrate were 1.84(Group A),1.51(Group B),0.92(Group C)and 0.71(Group D)respectively. The percentage of triglyceride decrement after rumen fermentation calculated the fat hydrolisis rate, and the saturated and unsaturated fatty acid proportion after rumen fermentation responded the hydrogenation degree. The results showed that there was significant difference of fat adipolysis rate between the group of A(21.80%)and D(31.22%)(P<0.05),insignificant difference between B(26.31%)and C(26.65%)(P>0.05),meanwhile triglyceride adipolysis rate was facilitated with decrease of SC:NSC. The max group D was 31.22%. The proportion of hydride stearic acid and saturated fatty acids were significant difference between group C and other(P<0.05),also the group of A,B and D were insignificant differenc(eP>0.05). The proportion of unsaturated fatty acids in group C was significant lower than other group(P<0.05),the three other groups were insignificant difference(P>0.05).The ratio of saturated and unsaturated fatty acids in group C was 1.63, which was significant lower than other groups(P<0.05).The results of this study indicated that existence of a suitable value of SC:NSC=0.92 could make rumen fatty acids hydrogenation remained at a lower level, to facilitate functional fatty acid absorption in the rumen and accumulation in the animal products.Experiment 3. The objective of this study was to investigate the effect of 4 different proportions of sheep dietary structural and nonstructural carbohydrates on composition of sheep milk fatty acids through feeding experiment, and 4 proportions of structural and nonstructural carbohydrate were 1.84(Group A),1.51(Group B),0.92(Group C)and 0.71(Group D)respectively. Experimental design used single factor and the experiment is divided four times, each issue of 8 days. At the start of the experiment sheeps were the approximately physical condition. Measurements were made during the last three days. After sample mix and 8℃the freezing offcenter, getting milk-fat from the upper layer which carried on the fat extraction purification through the proportion of cetane and the isopropyl alcohol was 3:2. Subsequently, the sample was methyl esterified through methyl acetate, the sodium hydroxide methyl alcohol solution and composition of milk fat was analyzed by gas chromatograph. The results showed that the contents of C10:0,C12:0,C14:1 in milk fat were 5.2862,3.2572,0.5787(μg/μL)from group's D which was higher than other three groups significantly(P<0.05). Relative to other groups,total unsaturated fatty acids was 7.23μg/μL and significant differece(P<0.05)from diets group of D. The ratio of unsaturated and saturated fatty acids was increased with SC:NSC decrease, the same tendency as both C12:0 and C14:1. Being SC:NSC was 0.92, the contents of total fatty acids, total polyunsaturated fatty acids, linoleic acid were significant higher than other three groups(P<0.05)so that functionality polyunsaturated fatty acids was enriched and milk products had with higher nutrition.