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1.
Background: The positive influence of replacing dietary starch with sugar on milk fat production has been proposed to be partially attributed to the inhibition of the rumen trans-10 biohydrogenation pathway. However,whether and how sucrose inhibits the rumen trans-10 biohydrogenation pathway remains elusive.Results: A batch in vitro incubation system was used to evaluate effects of replacing cornstarch in a high-concentrate diet(forage to concentrate ratio = 40:60) with 0(control), 3, 6 and 9 % of sucrose on rumen fermentation pattern, fatty acid(FA) biohydrogenation pathways and bacterial populations relating to trans-11 to trans-10 biohydrogenation pathways. Replacing dietary cornstarch with sucrose did not alter rumen p H or concentrations of total volatile fatty acids(VFA) in comparison with the control but significantly influenced the profiles of individual VFA. The molar proportions of butyrate and valerate were linearly increased, while that of acetate was quadratically decreased and those of propionate, isobutyrate and isovalerate were linearly decreased with increasing concentrations of sucrose in the diet. Furthermore, replacing cornstarch with sucrose led to a linear decrease in C18:1 trans-10, linear increases in the proportions of C18:1 trans-11, C18:2n-6 and the ratio of trans-11 to trans-10, and linear decreases in biohydrogenation of C18:2n-6 and C18:3n-3. The abundance of Butyrivibrio fibrisolvens, a butyrate and CLA cis-9,trans-11 producer, was increased with the increasing inclusion of sucrose in the diet, while the population of Megasphaera elsdenii, a CLA trans-10, cis-12 producer, was significantly decreased by all levels of sucrose replacements.Conclusions: These results indicate that replacing starch in a high-concentrate diet with sucrose increased butyrate production and inhibited the rumen trans-10 biohydrogenation pathway, which was at least partially due to increased abundance of Butyrivibrio fibrisolvens and decreased abundance of Megasphaera elsdenii.  相似文献   

2.
Four different plant secondary metabolites were screened for their effect on rumen biohydrogenation of forage long-chain fatty acids, using dual-flow continuous culture fermenters. Treatments were as follows: control (no additive), positive control (12 mg/L of monensin), and plant extracts (500 and 1,000 mg/L of triterpene saponin; 250 and 500 mg/L of quercetin; 250 mg/L of eugenol; 500 mg/L of cinnamaldehyde). Monensin increased propionate, decreased acetate and butyrate proportions, and inhibited the complete biohydrogenation of fatty acids resulting in the accumulation of intermediates of the biohydrogenation process (C18:2 trans-11, cis-15 rather than C18:1 trans-11). Cinnamaldehyde decreased total VFA concentration and proportions of odd and branched-chain fatty acids in total fat effluent. Apparent biohydrogenation of C18:2n-6 and C18:3n-3 was also less, and a shift from the major known biohydrogenation pathway to a secondary pathway of C18:2n-6 was observed, as evidenced by an accumulation of C18:1 trans-10 and trans-10, cis-12 CLA. Quercetin (500 mg/L) increased total VFA concentration, but no shifts in the pathways or extent of biohydrogenation were observed. Eugenol resulted in the accumulation of C18:1 trans-15 and C18:1 cis-15, end products of an alternative biohydrogenation pathway of C18:3n-3. Triterpene saponins did not affect the fermentation pattern, the biohydrogenation pathways, or the extent of biohydrogenation. At the doses tested in this study, we could only show a direct relation between changes in the rumen fatty acid metabolism and the presence of cinnamaldehyde but not for eugenol, quercetin, or triterpene saponins.  相似文献   

3.
The effects of dietary algal supplementation, a source of docosahexaenoic acid, on the fatty acid profile of rumen lipids in cattle were evaluated, with special emphasis on CLA and trans fatty acids produced by rumen microbes. A diet based on corn silage was fed with supplements containing the following: 1) no algal meal and fed at 2.1 kg of DM/d (control), 2) algal meal and fed at 1.1 kg of DM/d (low algal meal), 3) algal meal and fed at 2.1 kg of DM/d (medium algal meal), and 4) algal meal and fed at 4.2 kg of DM/d (high algal meal). A modified lipid extraction procedure was developed to analyze the lipid changes in rumen fluid. The percentage of stearic acid (18:0) in rumen fluid was decreased by algal meal supplementation (P < 0.001) compared with control and was linearly dependent on the level of algal meal supplementation (P = 0.005). Total trans-18:1 in rumen fluid of cattle fed the control diet was 19% of total fatty acids. Addition of algal meal increased (P < 0.001) total trans-18:1 up to 43%, mostly due to 18:1 trans-10 that increased (P = 0.002) to 29.5% of total rumen fatty acids. This increase in 18:1 trans-10 seems to suggest a change in the rumen microbial population. Vaccenic acid (18:1 trans-11) increased quadratically (P = 0.005) with increasing level of algal meal supplementation in the diets. The total CLA content was low in the control (<0.9%) and increased with dietary algal meal addition, although not significantly; the greatest level was 1.5% with the medium algal meal diet. The increase of rumenic acid (cis-9, trans-11 CLA) was quadratic (P = 0.05) with algal meal supplementation, whereas trans-10, cis-12 CLA increased linearly with increased level of algal meal from 0.08 to 0.13% (P = 0.03). The ratio of trans-11 (cis-9, trans-11 CLA + 18:1 trans-11) to trans-10 (trans-10, cis-12 CLA + 18:1 trans-10) decreased from 2.45 to 0.77, 0.87, and 0.21 for the control, low algal meal, medium algal meal, and high algal meal diets, respectively. The content of docosahexaenoic acid in rumen fluid increased (P = 0.002) from 0.3 to 1.4% of total fatty acids with increasing level of algal meal supplementation in the diets. Our results suggest that algal meal inhibits the reduction of trans-18:1 to 18:0, giving rise to the high trans-18:1 content. In conclusion, algal meal could be used to increase the concentration in rumen contents of trans-18:1 isomers that serve as precursors for CLA biosynthesis in the tissues of ruminants.  相似文献   

4.
Six Hereford steers (295 kg) cannulated in the proximal duodenum were used to evaluate the effects of forage and sunflower oil level on ruminal biohydrogenation (BH) and conjugated linoleic acid (CLA) outflow. Steers were fed one of six treatment diets in a 3 x 2 factorial arrangement of treatments (grass hay level: 12, 24, or 36% of DM; and sunflower oil level: 2 or 4% of DM) in a 6 x 6 Latin square design. The remainder of the diet was made up of steam rolled corn and protein/mineral supplement. Duodenal samples were collected for 4 d following 10-d diet adaptation periods. Data were analyzed with animal, period, forage level, sunflower oil level, and two-way interaction between forage and sunflower oil level in the model. Dry matter intake showed a quadratic response (P < 0.04), with an increase in DMI as forage level increased from 12 to 24% followed by a decrease in DMI when 36% forage was fed. Flow of fatty acids at the duodenum was higher (P < 0.03) for 4 vs. 2% sunflower oil diets, and similar among forage levels. Apparent ruminal digestibility of NDF increased in a linear manner (P < 0.04) as dietary forage level increased. Ruminal BH of dietary unsaturated 18-C fatty acids, oleic acid, and linoleic acid increased linearly (P < 0.05) as dietary forage level increased. Linoleic acid BH tended (P < 0.07) to be greater for 4 than 2% sunflower oil level. Duodenal flow of pentadecyclic, stearic, linolenic, and arachidic acids increased linearly (P < 0.05) as dietary forage level increased from 12 to 36%. Duodenal flow of linoleic acid decreased in a linear manner (P < 0.03) with increasing dietary forage level. Flow of trans-10 octadecenoate decreased linearly (P < 0.03) as dietary forage level increased, whereas trans-11 vaccenic acid flow to the duodenum increased (P < 0.01) linearly with increased dietary forage. Dietary forage or sunflower oil levels did not alter the outflow of cis-9, trans-11 CLA. Flows of cis-11, trans-13, and cis-9, cis-11 CLA increased linearly (P < 0.05) with increased dietary forage. Flows of cis-11, cis-13, and trans-11, trans-13 CLA decreased linearly (P < 0.05) with increased dietary forage. Increasing dietary forage levels from 12 to 36% in beef cattle finishing diets increased BH of unsaturated 18-C fatty acid and outflow of trans-11 vaccenic acid to duodenum without altering cis-9, trans-11 CLA outflow.  相似文献   

5.
Five beef cattle management regimens were evaluated for their effect on meat quality, fatty acid composition, and overall palatability of the longis-simus dorsi (LD) muscle in Angus cross steers. A 98-d growing phase was conducted using grass silage with or without supplementation of growth promotants (Revalor G and Rumensin) or soybean meal. Dietary treatments in the finishing phase were developed with or without supplementation of growth promotants based on exclusive feeding of forages with no grain supplementation, or the feeding of grain:forage (70:30) diets. Growth promotants increased (P < 0.01) shear force and tended (P = 0.06) to increase toughness of the LD muscle due to limited postmortem proteolytic activity (lower myofibrillar fragmentation index value; P = 0.02). Grain feeding increased DM and intramuscular fat content (P = 0.03 and P = 0.05, respectively) in the LD but decreased the sensory panel tenderness score (P = 0.01). Growth promotants increased (P 相似文献   

6.
We hypothesized that manipulating metabolism with fish oil and malate as a hydrogen acceptor would affect the biohydrogenation process of α‐linolenic acid by rumen microbes. This study was to examine the effect of fish oil and/or malate on the production of conjugated fatty acids and methane (CH4) by rumen microbes when incubated with linseed oil. Linseed oil (LO), LO with fish oil (LO‐FO), LO with malate (LO‐MA), or LO with fish oil and malate (LO‐FO‐MA) was added to diluted rumen fluid, respectively. The LO‐MA and LO‐FO‐MA increased pH and propionate concentration compared to the other treatments. LO‐MA and LO‐FO‐MA reduced CH4 production compared to LO. LO‐MA and LO‐FO‐MA increased the contents of c9,t11‐conjugated linoleic acid (CLA) and c9,t11,c15‐conjugated linolenic acid (CLnA) compared to LO. The content of malate was rapidly reduced while that of lactate was reduced in LO‐MA and LO‐FO‐MA from 3 h incubation time. The fold change of the quantity of methanogen related to total bacteria was decreased at both 3 h and 6 h incubation times in all treatments compared to the control. Overall data indicate that supplementation of combined malate and/or fish oil when incubated with linseed oil, could depress methane generation and increase production of propionate, CLA and CLnA under the conditions of the current in vitro study.  相似文献   

7.
Three Angus steers (410 kg) cannulated in the proximal duodenum were used in a replicated 3 x 3 Latin square to evaluate the effects of dietary lipid level and oil source on ruminal biohydrogenation and conjugated linoleic acid (CLA) outflow. Dietary treatments included: 1) typical corn (TC; 79.2% typical corn), 2) high-oil corn (HOC; 79.2% high-oil corn), and 3) the TC diet with corn oil added to supply an amount of lipid equal to the HOC diet (OIL; 76.9% TC + 2.4% corn oil). Duodenal samples were collected for 4 d following 10-d diet adaptation periods. Data were analyzed with animal, square, period, and treatment in the model and planned, nonorthogonal contrasts were used to test the effects of dietary lipid content (TC vs HOC and OIL) and oil source (HOC vs OIL) on ruminal biohydrogenation. Intake and duodenal flow of total long-chain fatty acids were increased (P < 0.05) by over 63% for diets containing more lipid regardless of oil source. Apparent ruminal dry matter and long chain fatty acid digestibilities were not altered (P > 0.05) by dietary lipid level or oil source. Ruminal biohydrogenation of total and individual 18-carbon unsaturated fatty acids was greater (P < 0.05) for diets with higher lipid content. Biohydrogenation of oleic acid was greater (P < 0.05) for HOC than OIL, but biohydrogenation of linoleic acid was lower (P < 0.05) for HOC than OIL. Duodenal flows of palmitic, stearic, oleic, linoleic, and arachidic acids were more than 30% greater (P < 0.05) for diets containing more lipid. Flow of all trans-octadecenoic acids was greater (P < 0.05) for diets containing more lipid. Corn oil addition increased (P < 0.05) the flow of trans-10 octadecenoic acid and the trans-10, cis-12 isomer of CLA by threefold compared to feeding high-oil corn. Feeding high-oil corn or adding corn oil to typical corn rations increased intake, biohydrogenation, and duodenal flow of unsaturated long-chain fatty acids. Compared with high-oil corn diets, addition of corn oil increased duodenal flow of trans-10, trans-12 and cis-12 isomers of octadecenoic acid and the trans-10, cis-12 isomer of CLA. The amount of cis-9, trans-11 isomer of conjugated linoleic acid flowing to the duodenum was less than 260 mg/d, a value over 20 times lower than flow of trans-11 vaccenic acid indicating the importance of tissue desaturation for enhanced conjugated linoleic acid content of beef.  相似文献   

8.
Conjugated linoleic acid (CLA), a mixture of isomers of linoleic acid, has many beneficial effects, including decreased tumor growth in animal cancer models. The cis-9, trans-11 isomer of CLA (CLA9,11) can be formed in the rumen as an intermediate in biohydrogenation of linoleic acid. Recent data, however, indicate that tissue desaturation of trans-fatty acids is an important source of CLA9,11 in milk. Our objective was to determine whether supplementing a high-corn diet with soybean oil (SBO; a source of linoleic acid) would increase concentrations of CLA in ruminal contents and tissue lipids. Four ruminally cannulated steers were utilized in a Latin square design with 28-d periods. A control diet (80% cracked corn, 2.0% corn steep liquor, 8.0% ground corn cobs, and 10% supplement [soybean meal, ground shelled corn, minerals, and vitamins]) was supplemented with 2.5, 5.0, or 7.5% (DM basis) SBO. Supplemental SBO did not affect ruminal pH or concentrations of the major VFA. The proportion and amount (mg FA/g DM ruminal contents) of CLA9,11 were not increased by increasing dietary SBO. However, the proportion and amount of the trans-10, cis-12 CLA isomer (CLA10,12) in ruminal contents increased linearly (P < 0.006) as dietary SBO increased. Trans-18:1 isomers in ruminal contents increased linearly (P < 0.02) as dietary SBO increased. The proportion of CLA10,12 was correlated positively (P < 0.001) with proportions of trans-C 18:1 isomers in ruminal contents. Conversely, CLA9,11 was correlated negatively (P < 0.05) with the proportions of trans-18:1 in ruminal contents. The same high-corn diet, supplemented with 0 or 5% SBO, was fed to 20 Angus-Wagyu heifers for 102 d in a randomized complete block design to determine the effect of added SBO on tissue deposition of CLA. Supplemental SBO did not affect feed intake, gain:feed, or carcass quality. Tissue samples were obtained from the hindquarter, loin, forequarter, liver, large and small intestine, and subcutaneous, mesenteric, and perirenal adipose depots. The concentration of CLA9,11 was greatest in subcutaneous adipose tissue but was not affected in any tissue by SBO. Supplementing high-corn diets with SBO does not increase CLA9,11 concentrations in tissues of fattening heifers. Research is needed to identify regulatory factors for pathways of biohydrogenation that lead to increased concentrations of CLA10,12 in ruminal contents when high-oil, high-concentrate diets are fed.  相似文献   

9.
Two experiments were conducted to determine the effectiveness of a rumen-protected CLA (pCLA) supplement and the impact of feeding this pCLA on carcass characteristics and tissue fatty acid composition of lambs. In Exp. 1, a CLA-80 preparation (80% pure CLA; contained similar proportions of cis-9, trans-11, and trans-10, cis-12 CLA), protected against rumen degradation, was fed to sheep, and the proportion of CLA reaching the duodenum was determined. A 3 x 3 Latin square design was used with 3 diets (1.4 kg of concentrate-based control diet, the same control diet plus 22 g of CLA-80, or the same control diet plus 110 g of pCLA/d), 3 feeding periods, and 3 rumen and duodenally cannulated sheep (Mule x Charolais males, 10 mo of age, BW 55.3 +/- 1.8 kg). After 7 d of feeding, sheep were ruminally infused with chromium EDTA and Yb acetate for 7 d, after which samples of duodenal digesta were collected every 6 h for 48 h to determine the quantity of CLA reaching the small intestine each day. The amounts of CLA cis-9, trans-11 and trans-10, cis-12, and combined isomers, flowing through the duodenum each day were greater (P = 0.01) in sheep fed pCLA. Approximately 65% of the pCLA avoided rumen biohydrogenation, with the ratio of the 2 main isomers remaining similar. In Exp. 2, 36 Mule x Charolais ewe lambs (approximately 13-wk old, average initial BW 29.3 kg) were fed 3 levels of the pCLA or Megalac, which were fed to provide an equivalent energy content at each pCLA level. Lambs were randomly assigned to 1 of 7 treatment groups, which were fed for 10 wk to achieve a growth rate of 180 g/d. Treatments included the basal diet and the basal diet plus 25, 50, or 100 g of pCLA/kg of diet or the equivalent amount of Megalac. In liver (P < 0.001) and all adipose tissue depots studied, the proportions of both CLA isomers increased (P = 0.02) with the amount of pCLA fed but were not altered with increasing of Megalac. Although there was no effect of treatment on cis-9, trans-11 CLA content, accumulation (P < 0.001) in the LM with increasing of pCLA supplementation was observed for the trans-10, cis-12 isomer. Although tissues had been enriched with CLA, there was no evidence of a reduction in adipose tissue or an increase in muscle mass in these sheep. However, an effect of pCLA on tissue fatty acid composition was consistent with an inhibition of stearoyl-CoA desaturase.  相似文献   

10.
Eighteen steers were used to evaluate the effect of supplemental corn oil level to steers grazing endophyte-free tall fescue on fatty acid composition of LM, stearoyl CoA desaturase (SCD) activity and expression as well as cellularity in s.c. adipose. Corn oil was supplemented (g/kg of BW) at 0 (none), 0.75 (medium), and 1.5 (high). Cottonseed hulls were used as a carrier for the corn oil and were supplemented according to pasture availability (0.7 to 1% of BW). Steers were finished on a rotationally grazed, tall fescue pasture for 116 d. Fatty acid composition of LM, s.c. adipose, and diet was determined by GLC. Total linoleic acid intake increased linearly (P < 0.01) with corn oil supplementation (90.7, 265.1, and 406.7 g in none, medium, and high, respectively). Oil supplementation linearly reduced (P < 0.05) myristic, palmitic, and linolenic acid percentage in LM and s.c. adipose. Vaccenic acid (C18:1 t11; VA) percentage was 46 and 32% greater (linear, P = 0.02; quadratic, P = 0.01) for medium and high, respectively, than none, regardless of tissue. Effect of oil supplementation on CLA cis-9, trans-11 was affected by type of adipose tissue (P < 0.01). In the LM, CLA cis-9, trans-11 isomer was 25% greater for medium than for none and intermediate for high, whereas CLA cis-9, trans-11 CLA isomer was 48 and 33% greater in s.c. adipose tissue for medium and high than for none, respectively. Corn oil linearly increased (P 0.05) the percentage of total SFA, MUFA, or PUFA but linearly increased (P = 0.03) n-6:n-3 ratio from 2.4 to 2.9 in none and high, respectively. Among tissues, total SFA and MUFA were greater in s.c. adipose than LM, whereas total PUFA, n-6, and n-3 fatty acids and the n-6:n-3 ratio were lower. Trans-10 octadecenoic acid, VA, and CLA trans-10, cis-12 were greater (P < 0.01) in s.c. adipose than in LM. Oil supplementation did not alter (P > 0.05) stearoyl CoA desaturase activity or mRNA expression. Corn oil supplementation to grazing steers reduced the percentages of highly atherogenic fatty acids (myristic and palmitic acids) and increased the percentages of antiatherogenic and anticarcinogenic fatty acids (VA and cis-9, trans-11 CLA).  相似文献   

11.
The objective of the study was to determine temporal fat deposition and fatty acid profiles in beef cows fed hay- or barley silage-based diets, with or without flaxseed. Crossbred cull beef cows (n = 64, >30 mo of age, 620 ± 5 kg) were removed from grassland pastures, randomly assigned to 16 pens, and given ad libitum access to 50:50 (wt/wt, DM basis) forage:concentrate diets containing 0 or 15% ground flaxseed (DM basis, 5.2% added fat). Diets consisted of hay control (HC), hay+flaxseed (HF), barley silage control (SC), and silage+flaxseed (SF). Backfat biopsies were obtained from each cow at 0, 6, and 12 wk, and at slaughter (~20 wk) to assess fatty acid composition. With the exception of feed efficiency, flaxseed × forage interactions were not significant for backfat accumulation or performance parameters. Flaxseed improved (P < 0.01) feed conversion when supplemented to hay-based diet and increased ADG (P = 0.03), resulting in a heavier (P = 0.02) BW. Compared with hay, barley silage increased (P < 0.01) DMI, ADG, and feed efficiency. Subcutaneous fat contained 0.68% n-3 fatty acids at wk 0, and reached 0.68, 0.81, and 0.94% in HF cows after 6, 12, and 20 wk, respectively (Y(n-3) = 0.0133X + 0.6491, r = 0.87). It was 0.67% at wk 0, and reached 0.65, 0.77, and 0.90% in SF cows after 6, 12, and 20 wk, respectively (Y(n-3) = 0.0121X + 0.6349, r = 0.75). In contrast, weight percentage of n-3 fatty acids decreased in HC cows from 0.63, 0.50, and 0.47, to 0.43%, and in SC cows from 0.63, 0.40, and 0.36, to 0.33% over the 20 wk. A forage × flaxseed interaction (P < 0.05) occurred for many of the α-linolenic acid (ALA) biohydrogenation intermediates, including vaccenic acid (C18:1 trans-11) and CLA (combined C18:2 trans-7,cis-9 and cis-9,trans-11) in plasma, and in subcutaneous fat this also included non-CLA dienes. Concentrations of most α-linolenic acid biohydrogenation intermediates were greater when feeding flaxseed with hay. In conclusion, forage source altered plasma concentrations and rate of accumulation of ALA biohydrogenation products in subcutaneous fat from beef cows fed flaxseed. Factors responsible for this response are yet to be defined, but may include forage-mediated changes in ruminal biohydrogenation of ALA, as well as alterations in fatty acid metabolism and deposition.  相似文献   

12.
Xu CX  Oh YK  Lee HG  Kim TG  Li ZH  Yin JL  Jin YC  Jin H  Kim YJ  Kim KH  Yeo JM  Choi YJ 《Journal of animal science》2008,86(11):3033-3044
The present study was conducted to examine the effects of different plant oils or plant oil mixtures and high-temperature, microtime processing (HTMT) on the CLA content in Hanwoo steers. Experiment 1, consisting of 3 in vitro trials, was conducted to determine how the biohydrogenation of C18 fatty acids and CLA production were affected by fat sources (tallow, soybean oil, linseed oil, or mixtures of soybean oil and linseed oil) or HTMT treatment in the rumen fluid. The results showed that HTMT was capable of protecting unsaturated fatty acids from biohydrogenation by ruminal bacteria. The HTMT-treated diet containing 4% linseed oil (LU) and a supplement containing 2% linseed oil and 1% soybean oil treated with HTMT + 1% soybean oil (L(2)S(1)U+S(1)) produced an increased quantity of trans-11 C18:1 and cis-9, trans-11 CLA, and a reduced quantity of trans-10, cis-12 CLA. Based on these results, in vivo studies (Exp. 2) were conducted with LU and L(2)S(1)U+S(1). These 2 treatments increased the content of cis-9, trans-11 CLA in LM compared with the control diet. The content of trans-10, cis-12 CLA in subcutaneous fat was also increased in the L(2)S(1)U+S(1) treatment compared with other treatments. The subcutaneous fat thickness in the LU treatment was decreased compared with the L(2)S(1)U+S(1) treatment. The LU treatment significantly decreased fatty acid synthase expression but simultaneously increased leptin expression. In this report, we showed that diets containing LU and L(2)S(1)U+S(1) were capable of increasing CLA in the intramuscular fat of beef.  相似文献   

13.
In vitro anaerobic incubations were used to determine the effect of different oils (LO-linseed, SO-sunflower, FO-fish oil) on trans fatty acid production in rumen fluid and to test if combining of monensin (MON) with the oils affects the interactions on trans fatty acid concentrations in mixed cultures of ruminal microorganisms. Two different sources of rumen fluid were used; the inoculum from the sheep fed hay and barley (80:20%)--the inoculum A and the inoculum from the sheep fed alfalfa and barley (80:20 %)--the inoculum B. The analyses showed that inoculum B contained more short chain fatty acids (SCFA), medium chain fatty acids (MCFA) and saturated fatty acids (SFA) than inoculum A. In contrast, inoculum A contained more unsaturated fatty acids (UFA) than inoculum B. The results show, that the oils affected the biohydrogenation of fatty acids (FA) by increasing the concentration of C18:0 (3-7 times) and trans C18:1 isomers (2-9 times). The concentration of two main intermediates of FA biohydrogenation-- cis 9, trans 11 C18:2 (CLA) and trans 11C18:1 (TVA) were increased with the oils, but FO was more efficient than other plant oils on CLA and TVA production.The monensin treatment had similar effect on FA metabolism as the oil treatment in comparison to unincubated control. The interactions of monensin treatment with the oils were characterized with decrease (LO+MON, SO+MON) or increase (FO+MON) of the proportions of C18:0 and trans C18:1 isomers in comparison to oil treatment.The highest concentrations of two main isomers--CLA,TVA were found in the samples containing fish oil and monensin. In conclusion, fish oil treatment and monensin with fish oil treatment was more efficient than other plant oils in the effect on trans fatty acid production (mainly CLA and TVA) in fermentation fluid in vitro.  相似文献   

14.
Diet digestibility and outputs of biohydrogenation intermediates were assessed in a continuous culture of ruminal microorganisms. Orchardgrass or red clover harvested and frozen during spring or fall served as the primary substrates for fermentation. During 10-d incubations, fermenters were fed thawed forage (50 g of DM/d), forage (42 g/d) plus 8 g/d of corn, or forage (34 g/d) plus 16 g/d of corn. Effluents from the last 3 d of incubation were composited for analyses. Starch input increased from 5 to 27% of DM as corn input increased from 0 to 16 g/d. Corn input reduced (P < 0.01) pH, increased (P < 0.01) microbial DM yield, and increased (P = 0.01) digestibility of DM, NDF, CP, and nonstructural carbohydrates. Overall, apparent hydrogenation (percentage) of cis9-18:1, 18:2n-6, and 18:3n-3 was greater (P < 0.05) with orchardgrass than clover. Hydrogenation of cis9-18:1 and 18:2n-6 increased (P = 0.01), but hydrogenation of 18:3n-3 decreased (P = 0.01) linearly due to corn input, regardless of forage. As a result, output of trans11, cis15-18:2 also decreased (P = 0.01). Average output of cis9,trans11-18:2 was greater (P = 0.01) for clover (1.3 mg/d) compared with orchardgrass (0.6 mg/d), but corn input with either forage increased (P = 0.01) cis9,trans11-18:2 output by 205%. Output of trans11-18:1 was greater (P = 0.01) from orchardgrass compared with clover (174 vs. 90 mg/d), but corn increased (P = 0.01) trans11-18:1 output only from clover fermentations. Output of trans10-18:1 was greater (P = 0.01) in response to orchardgrass compared with clover (10 vs. 4 mg/d), but corn addition doubled the output regardless of forage type. Output of trans10,cis12-18:2, which did not differ due to forage type, increased (P = 0.01) twofold in response to corn. Cis9,cis11-18:2 was a primary conjugated isomer produced from forage fermentations, but its output decreased (P = 0.03) in response to corn input. When inputs of 18:2n-6 plus 18:3n-3 were less than 0.9% of total DM (clover), hydrogenation was low (87%). When 18:2n-6 plus 18:3n-3 inputs were from 1.2 to 1.5% of total DM (orchardgrass), hydrogenation averaged 96%. Despite greater hydrogenation, incremental additions of cis9-18:1 and 18:2n-6 from corn grain increased (P < 0.05) outputs of trans10-18:1, trans11-18:1, trans10,cis12-18:2, cis9,trans11-18:2, and trans,trans-18:2 in effluent. Results suggest that forage species alone or in combination with corn grain can alter hydrogenation and profiles of intermediates to varying degrees.  相似文献   

15.
A steer finishing trial was performed to determine the effect of short-term dietary regimens on conjugated linoleic acid (CLA) content of muscle tissues. The experimental design was an incomplete 3 x 2 factorial, with three levels of soybean oil (SBO; 0, 4, and 8% of diet DM) and two levels of forage (20 vs. 40% of diet DM). Forty Angus x Hereford steers averaging 504 +/- 29.0 kg were allotted randomly to one of four treatments for the last 6 wk of the finishing period. Treatments were: 80:20 concentrate:forage control diet (C); 80:20 concentrate:forage + 4% SBO (C4); 60:40 concentrate:forage + 4% SBO (F4); and 60:40 concentrate:forage + 8% SBO (F8). After 42 d on the experimental diets, steers were sacrificed and samples were collected from the chuck, loin, and round muscle groups. Fatty acid (FA; mg/100 mg of FA) composition was determined by gas-liquid chromatography. Data were statistically analyzed with mixed models procedures. The performance and carcass quality model included the effects of SBO and forage. The model for FA composition included the effects of SBO, forage, muscle group, and interactions. Orthogonal contrasts were used to determine linear effects of SBO. There were no differences in growth performance among treatments (P > 0.05). Increasing dietary SBO linearly decreased dressing percent (P = 0.04), and tended to linearly decrease marbling score (P = 0.12) and quality grade (P = 0.08). The only CLA isomer detected in tissue samples was cis-9,trans-11. Addition of SBO to diets linearly increased linoleic acid (18:2n-6; P = 0.04) and tended to linearly increase linolenic acid (18:3n-3; P = 0.10) in muscle tissues. The CLA in lean tissues was decreased (P = 0.005) with SBO-containing diets. These findings suggest that increased PUFA may limit ruminal production of CLA and trans-vaccenic acid (VA) and/or may depress stearoyl-CoA desaturase expression or activity in lean tissues, which in turn limits CLA formation and accretion in tissues. Increasing dietary forage tended to increase 18:0, 18:2n-6, CLA, and 18:3n-3 (P < 0.15), suggesting that increased forage may mitigate toxic effects of PUFA on ruminal biohydrogenation, thereby increasing the pool of CLA and VA available for CLA formation and accretion in tissues. Short-term feeding of elevated SBO and forage levels can alter FA profiles in muscle tissues.  相似文献   

16.
Thirty-six Angus x Hereford heifers (365 +/- 60 kg) were used to determine the effects of supplemental dietary lipid sources on fatty acid composition of i.m., perianal (p.a.), and s.c. lipid depots. Lipid was supplied to diets as either corn oil or a rumen-protected conjugated linoleic acid (CLA) salt for two specific treatment periods of either the final 32 or 60 d on feed. Following an initial 56-d feeding period, heifers were fed one of three dietary treatments (DM basis): 1) basal diet containing 88% concentrate and 12% grass hay (CON), 2) basal diet plus 4% corn oil (OIL), or 3) basal diet plus 2% rumen-protected CLA salt (RPCLA) containing 31% CLA. The trans-10, cis-12 CLA concentration was greatest (P < 0.05) for heifers fed RPCLA and OIL diets and least (P < 0.05) for CON, regardless of time on dietary treatment. Heifers fed supplemental RPCLA had greater (P < 0.05) total CLA content than either CON- or OIL-fed heifers. Adipose tissue concentration of trans-11 vaccenic acid (TVA) was less (P < 0.05) for CON than OIL or RPCLA, which did not differ (P > 0.05). Percentages of C18:1 trans-10 were least (P < 0.05) in i.m. lipid compared with p.a. and s.c., which did not differ (P > 0.05). Following 60 d of lipid supplementation, heifers fed OIL and RPCLA had lower (P < 0.05) concentrations of oleic acid and total monounsaturated fatty acids (MUFA) compared with CON. The ratio of cis-9, trans-11 CLA:TVA was higher (P < 0.05) for heifers fed 60 vs. 32 d, but did not differ (P > 0.05) between adipose depots. Feeding OIL increased (P < 0.05) adipose concentration of C18:2 fatty acid, whereas feeding RPCLA increased (P < 0.05) total CLA isomers by 22%. Intramuscular lipid contained the lowest (P < 0.05) percentage of cis-9, trans-11 CLA, total CLA, C18:1 cis-9, C18:1 trans-10, and TVA. Total CLA and cis-9, trans-11 CLA isomers were increased (P < 0.05) in p.a. and s.c. adipose depots, whereas i.m. adipose tissue contained increased (P < 0.05) amounts of total PUFA. Results from this study indicate that short-term lipid supplementation to feedlot cattle can increase adipose tissue CLA concentrations, but only marginally (8.3 to 17.5%). Moreover, observed decreases in oleic acid and total MUFA concentrations of adipose tissues from heifers fed rumen-protected CLA or corn oil suggest that lipid supplementation may decrease delta9 desaturase activity in adipose tissues, which in turn would lower the conversion of TVA to cis-9, trans-11 CLA isomer.  相似文献   

17.
Previous studies showed that oleamide was protected from ruminal biohydrogenation and increased 18:1(n-9) concentration in milk when fed to lactating dairy cows. To appraise whether this protection extended to linoleamide, a rumen in vitro experiment was conducted to determine biohydrogenation of linoleamide followed by two sheep experiments to evaluate whether linoleamide could increase 18:2 (n-6) concentration in duodenal contents. Treatments for the in vitro and sheep studies consisted of three diets containing no added lipid (control), linoleic acid, or linoleamide. Lipids were added at 10% (DM basis) of the in vitro substrate (ground grass hay). The three substrates were incubated with mixed ruminal microbes in triplicate, and 5 mL of culture contents was taken at 0, 24, and 48 h for analysis of 18:2 (n-6) concentration by gas chromatography. The concentrations of 18:2 (n-6) (corrected for 18:2 (n-6) in the control cultures) at 0, 24, and 48 h were 2.51, 0.38, and 0.11 mg/5 mL for the linoleic acid cultures compared to 2.10, 1.35, and 1.08 mg/5 mL for the linoleamide cultures. Compared to linoleic acid, the cultures containing linoleamide had higher 18:1 (n-9) and lower concentrations of biohydrogenation products including trans-18:1 and 18:0. Three sheep with duodenal cannulas were fed the three diets in two separate 3 x 3 Latin squares each with 2-wk periods. The two squares only differed in the amount of added lipid (1.5 vs 5% of the ration DM). When the lipids were added at 1.5% of the ration DM, they had little effect on duodenal 18:2 (n-6) concentration (2.8, 3.6, and 4.3 mg/g DM for the control, linoleic acid, and linoleamide treatments, respectively). At 5% of the ration DM, both lipid supplements increased duodenal 18:2 (n-6) concentration over the control diet with a greater response observed for linoleamide (2.5, 12.2, and 16.8 mg/g DM for the control, linoleic acid, and linoleamide treatments, respectively). This study demonstrates reduced biohydrogenation of linoleamide based on its ability to maintain a higher concentration of 18:2 (n-6) in ruminal cultures and in duodenal contents of sheep compared to free linoleic acid.  相似文献   

18.
We hypothesized that stearoyl-CoA desaturase (SCD) enzyme activity would not correlate with fatty acid indices of SCD activity in steers fed different grains. Forty-five Angus steers (358 +/- 26 kg BW) were individually fed for 107 d diets differing in whole cottonseed (WCS) supplementation (0, 5, or 15% of DM) and grain source (rolled corn, flaxseed plus rolled corn, or ground sorghum grain) in a 3 x 3 factorial arrangement. Flaxseed- and corn-fed steers had greater (P < 0.01) G:F (0.119 and 0.108, respectively) than sorghum-fed steers (0.093). Marbling score was decreased by WCS (P = 0.04), and LM area was decreased (P < 0.01) by sorghum. Plasma 14:0, 16:0, 16:1n-7, and 18:2n-6 were greatest in corn-fed steers, whereas plasma 18:3n-3 and 20:5n-3 were greatest in the flax-seed-fed steers (P < 0.01). Plasma 18:1trans-11 was least in sorghum-fed steers, and plasma cis-9,trans-11 CLA was barely detectable, in spite of high intestinal mucosal SCD enzyme activity (118 to 141 nmol*g tissue(-1).7 min(-1)). Interfascicular (i.f.) and s.c. cis-9,trans-11 CLA remained unchanged (P > or = 0.25) by treatment, although 18:1trans-11 was increased (P < or = 0.02) in steers fed corn or flaxseed. Steers fed flaxseed also had greater (P < 0.01) i.f. and s.c. concentrations of 18:3n-3 than steers fed the other grain sources. Oleic acid (18:1n-9) was least and total SFA were greatest (P < 0.01) in i.f. adipose tissue of steers fed 15% WCS. Lipogenesis from acetate in s.c. adipose tissue was greater (P < 0.01) in flaxseed-fed steers than in the corn- or sorghum-fed steers. Steers fed flaxseed or corn had larger i.f. mean adipocyte volumes (P < 0.01) than those fed sorghum and tended (P = 0.07) to have larger s.c. adipocyte volumes. Several fatty acid indices of SCD enzyme activity were decreased (P < or = 0.03) by WCS in i.f. adipose tissue, including the 18:2cis-9,trans-11/ 18:1trans-11 ratio. The 18:2cis-9,trans-11/18:1trans-11 ratio also tended to be decreased (P = 0.09) in s.c. adipose tissue by flaxseed; however, SCD enzyme activities in i.f. and s.c. adipose tissue were not affected by dietary WCS (P > or = 0.47) or grain source (P > or = 0.37). Differences in SFA seemed to be independent of SCD enzyme activity in both adipose tissues, suggesting that duodenal concentrations of fatty acids were more important in determining tissue fatty acid concentrations than endogenous desaturation by SCD.  相似文献   

19.
选用4只装有永久性瘤胃瘘管的杂交一代(小尾寒羊×无角陶赛特)羯羊(平均体重45.0kg),采用4×4拉丁方设计,研究日粮精料水平对绵羊瘤胃内容物中亚油酸及其氢化产物组成的影响。在日粮中添加大豆油,调整粗脂肪和亚油酸含量分别至(7.3±0.1)%和(25.4±0.9)mg/g(干物质基础),日粮精料水平分别为30.2,39.3,48.8和57.7%(干物质基础)。试验结果表明,57.7%精料日粮组瘤胃内容物中亚油酸的含量(mg/gDM)及其在总18C脂肪酸中的比例最高(P<0.01),反11C18∶1、顺9,反11CLA的含量及二者在总18C脂肪酸中的比例最低(P<0.01);各组瘤胃内容物中C18∶0的含量及其在总18C脂肪酸中的比例没有显著差异(P>0.05)。瘤胃内容物中亚油酸、顺9,反11CLA和反11C18∶1的含量与日粮NDF水平呈极显著线性相关(P<0.01)。亚油酸的氢化效率随日粮精料水平的提高而显著降低(P<0.05)。  相似文献   

20.
Thirty-six Angus x Hereford heifers were used in a 3 x 2 factorial (3 dietary treatments; 2 supplementation times) to examine the effect of dietary lipid supplementation on lipid oxidation, lipid composition, and palatability of ribeye steaks and ground beef. Lipid was supplied in the diets as corn oil or a partially rumen-protected CLA salt for 2 specific treatment periods of the final 32 or 60 d on feed, corresponding to a total time on feed of 89 or 118 d. After an initial 56-d feeding period (basal diet), the heifers were fed 1 of 3 dietary treatments (DM basis): 1) a basal diet containing 88% concentrate and 12% grass hay (CON), 2) the basal diet plus 4% corn oil (OIL), or 3) the basal diet plus 2% partially rumen-protected CLA (RPCLA) containing 31% CLA. Heifers were randomly allotted to dietary treatments at the initiation of the study and fed individually. At 48 h postmortem, the right forequarter of each carcass was fabricated into retail cuts. Steaks (2.54-cm thick) were obtained from the posterior end of the ribeye roll (NAMP 112), and beef trim was ground for all subsequent analyses. Dietary treatment did not affect (P > 0.05) lipid oxidation in ground beef or ribeye steaks. Total trans-octadecenoate fat and trans-10 octadecenoic acid content in ribeye steaks increased (P < 0.05) with RPCLA compared with CON. Total CLA and the cis-9 trans-11 isomer of CLA contents in ribeye steaks were unchanged (P > 0.05) by lipid supplementation. In ground beef, RPCLA supplementation increased (P < 0.05) the amount of trans fat and trans-10 octadecenoic acid compared with CON or OIL; supplementation of RPCLA increased (P < 0.05) the amount of CLA cis-9 trans-11 isomer and total CLA. Lipid supplementation did not alter (P > 0.05) off-flavor ratings in ground beef or ribeye steaks. Supplementation of corn oil increased (P < 0.05) total PUFA content of ribeye steaks compared with CON and RPCLA. Dietary RPCLA supplementation increased the amount of trans fat per serving (85.5 g, broiled) by 110 and 88% in ribeye steak and ground beef, respectively, and CLA cis-9 trans-11 by 58% in ground beef compared with CON. Supplementing OIL or RPCLA resulted in minimal changes in lipid oxidation and sensory attributes of steaks and ground beef.  相似文献   

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