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1.
Our objectives were to evaluate ruminal fermentation patterns, apparent ruminal biohydrogenation, and site and extent of nutrient disappearance in cattle fed supplemental cracked safflower seeds differing in 18 C fatty acid profile. Nine Angus x Gelbvieh heifers (641 +/- 9.6 kg) fitted with ruminal and duodenal cannulas were used in a triplicated 3 x 3 Latin square. Cattle were fed (OM basis) 9.1 kg of bromegrass hay and either 1) 1.8 kg of corn and 0.20 kg of soybean meal (Control); 2) 0.13 kg of soybean meal and 1.5 kg of cracked high-linoleate (67.2% 18:2) safflower seeds (Linoleate); or 3) 1.5 kg of cracked high-oleate (72.7% 18:1) safflower seeds (Oleate). Safflower seed supplements were formulated to provide similar quantities of N and TDN and 5% dietary fat. Single degree of freedom orthogonal contrasts (Control vs. Linoleate and Oleate; Linoleate vs. Oleate) were used to evaluate treatment effects. True ruminal OM and ruminal NDF disappearances (percentage of intake) were greater (P < or =0.02) for Control than Linoleate and Oleate. True ruminal N degradability (% of intake) was not different (P = 0.38) among treatments. Apparent ruminal biohydrogenation of dietary 18:2 was greatest (Linoleate vs. Oleate, P < 0.001) for Linoleate, whereas biohydrogenation of dietary 18:1 was greatest (Linoleate vs. Oleate, P = 0.02) for Oleate. Duodenal flow of 18:0 was least (P < 0.001) for Control but did not differ (P = 0.92) between Oleate and Linoleate. Total flow of unsaturated fatty acid to the duodenum was greatest (P < 0.001) in cattle fed safflower seeds, and was greater with Linoleate (P < 0.001) than with Oleate. Duodenal flow of 18:1 and 18:2 increased (P < 0.001) in Oleate and Linoleate, respectively. Duodenal flow of 18:1trans-11 was greater (P < 0.001) in cattle fed safflower seeds and in Linoleate than in Oleate. Postruminal disappearance of saturated fatty acids was greatest (P < 0.001) for Control; however, postruminal disappearance of total unsaturated fatty acids was greater (P = 0.002) for Linoleate vs. Oleate. Supplemental high-linoleate or high-oleate safflower seeds to cattle fed forage-based diets may negatively affect ruminal OM and fiber disappearance but not N disappearance. Provision of supplemental fat in the form of safflower seeds that are high in linoleic acid increased intestinal supply and postruminal disappearance of unsaturated fatty acids, indicating that the fatty acids apparently available for metabolism are affected by dietary fat source.  相似文献   

2.
日粮中添加整粒油籽对绵羊体脂脂肪酸组成的影响   总被引：1，自引：0，他引：1  
日粮中分别添加相当于40 g粗脂肪的油菜籽(canola)、油葵籽、红花籽和亚麻籽,饲喂成年母羊35 d后屠宰,用气相色谱技术测定了背最长肌、尾部、背膘和肾脏4个部位脂肪的脂肪酸(FA)组成,结果表明:1)红花籽可显著降低肌肉中的短链、长链饱和脂肪酸及总饱和脂肪酸(SFA)的比例,而增加单不饱和脂肪酸(MUFA)和总不饱和脂肪酸(UFA)的比例,而添加油菜籽对肌肉的FA无显著影响;2)油葵显著降低了尾部短链和中链脂肪酸,提高了多不饱和脂肪酸(PUFA)与SFA的比值(P:S),油菜籽可显著降低尾部短链脂肪酸;3)添加亚麻籽有增加所有组织UFA和P:S值,降低SFA的趋势,但只有背膘脂肪中的PUFA显著增高;4)各类油籽对脂肪组织中的总SFA和MUFA无明显影响,其中肾脏脂肪受影响最小.  相似文献   

3.
Our objective was to determine the effect of oil supplementation of pasture fed, beef cattle on the fatty acids, particularly CLA and PUFA, of muscle and s.c. adipose tissue. Forty-five Charolais crossbred heifers were blocked on BW and randomly assigned to 1 of 3 dietary regimens in a randomized complete block design (n = 15). The 3 treatments were: unsupplemented grazing (GO), restricted grazing plus a sunflower oil-enriched ration (SO), or restricted grazing plus a linseed oil-enriched ration (LO). Heifers were fed the experimental diets for approximately 158 d. Samples of LM muscle and s.c. adipose tissue were taken postmortem, the muscle fat was separated into neutral lipid and polar lipid (no separation was performed on the s.c. adipose tissue), and the fatty acid profile was determined by GLC. No effect of dietary treatment on carcass weight or total fatty acid concentration (mean 2,571 mg/100 g of muscle) in muscle fat was detected. Heifers offered SO had a greater (P < 0.001) proportion of CLA and C18:1trans-11 (1.90 and 9.35 vs. 1.35 and 6.89 g/100 g of fatty acids, respectively) in neutral lipid of muscle fat compared with those offered LO, which had a greater proportion of CLA and C18:1trans-11 than heifers offered GO (0.78 and 3.37 g/100 g of fatty acids, respectively). Similar effects were observed in the polar lipid and s.c. lipid. The PUFA:SFA ratio was greater in muscle fat and s.c. adipose tissue from supplemented heifers than in those offered GO (P < 0.001). Compared with LO, the PUFA:SFA ratio was greater (P < 0.05) in muscle fat of heifers offered SO, but there was no difference between SO and LO for this ratio in s.c. adipose tissue. The n-6:n-3 PUFA ratio was similar in muscle and s.c. adipose tissue for GO and LO, but it was greater (P < 0.05) for SO. It is concluded that supplementation of pasture-fed cattle with plant oil-enriched concentrates resulted in an increase in beef fat of some fatty acids considered to be of benefit to human health. Concentrates enriched with sunflower oil were more effective in increasing the CLA concentration, whereas linseed oil-enriched concentrates resulted in a more favorable n-6:n-3 PUFA ratio. The relevance to human health of the associated increase in C18:1trans-11 merits investigation.  相似文献   

4.
Two experiments were conducted with lactating Angus x Gelbvieh beef cows to determine the effects of postpartum lipid supplementation, BCS at parturition, and day of lactation on fatty acid profiles in plasma, adipose tissue, and milk. In Exp. 1, 36 pri-miparous cows (488 +/- 10 kg of initial BW; 5.5 +/- 0.02 initial BCS) were given ad libitum access to hay and assigned randomly to a low-fat (control) supplement or supplements with cracked, high-linoleate safflower seeds (linoleate) or cracked, high-oleate safflower seeds (oleate) from d 3 to 90 of lactation. Diets were formulated to be isonitrogenous and isocaloric; safflower seed diets provided 5% of DMI as fat. Plasma and milk samples were collected on d 30, 60, and 90 of lactation. Adipose tissue biopsies were collected near the tail-head region of cows on d 45 and 90 of lactation. In Exp. 2, 3-yr-old cows achieving a BCS of 4 +/- 0.07 (479 +/- 36 kg of BW) or 6 +/- 0.07 (580 +/- 53 kg of BW) at parturition were used in a 2-yr experiment (n = 36/yr). Beginning 3 d postpartum through d 61 of lactation, cows were fed diets similar to those of Exp. 1. Adipose tissue and milk samples were collected on d 30 and 60, and plasma was collected on d 31 and 61 of lactation. Responses to postpartum dietary treatment were comparable in both experiments. Cows fed linoleate and oleate had greater (P < 0.001) total fatty acid concentrations in plasma than cows fed control. Except for 15:1, milk fatty acids with <18 carbons were greatest (P < or = 0.01) for cows fed control, whereas milk from cows fed linoleate had the greatest (P < or = 0.02) 18:1trans-11, 18:2n-6, and cis-9, trans-11 CLA. Milk from cows fed oleate had the greatest (P < 0.001) 18:1cis-9. In Exp. 1, total fatty acid concentrations in adipose tissue samples decreased at d 90 compared with d 45 of lactation, but the fatty acid profile of cow adipose tissue was not affected (P = 0.14 to 0.80) by dietary treatment. In Exp. 2, the percentage of cis-9, trans-11 CLA in adipose tissue of cows with a BCS of 6 decreased (P = 0.001) from d 30 to 60 of lactation. Plasma and milk fatty acid composition reflected alterations in postpartum diet. Less medium-chain fatty acids and more 18-carbon fatty acids in milk were indicative of reduced de novo fatty acid synthesis in the mammary gland of beef cows fed lipid supplements; however, the metabolic demands of lactation prevented the deposition of exogenously derived fatty acids in adipose tissue through d 90 of lactation.  相似文献   

5.
We investigated conjugated linoleic acid (CLA) supplementation administered to heavy pigs, assessing carcass characteristics, meat quality, and sensory characteristics of dry-cured (Parma) ham. Thirty-six pigs, averaging 97 kg BW, were assigned randomly to three feeding groups in which diets were supplemented with either 0, 0.25, or 0.5% (as-fed basis) of a CLA preparation containing 65% CLA isomers. All pigs were slaughtered at 172 kg BW. No (P > 0.05) differences were observed in dressing percentage, loin and ham weight, or pH and color of longissimus and semimembranosus muscle. Tenth-rib backfat thickness tended to be lower (P < 0.10) in carcasses from CLA-fed pigs. The oxidative stability of longissimus muscle was greater (P < 0.05) in pigs fed CLA than control, but only at the longer (300 min) oxidation time. Acetyl-CoA carboxylase activity in adipose tissue of CLA-fed pigs was less (P < 0.05) than that of pigs fed diets devoid of supplemental CLA. Composition of ham fat was markedly affected (P < 0.01) by dietary CLA, with higher saturated fatty acids, lower monounsaturated fatty acids, and higher CLA in the fat of CLA-fed pigs regardless of supplementation level. Although melting quality was improved (P < 0.05), most sensory characteristics and the chemical composition of dry-cured hams were not (P > 0.05) affected by incorporation of CLA. Results indicated that dietary CLA alters lipid metabolism, producing lower concentrations of monounsaturated fatty acids and increased concentrations of CLA isomers in the fat of heavy pigs. Moreover, supplementing diets with CLA produced only minimal improvements in Parma ham sensory traits and had no appreciable effects on fresh pork quality.  相似文献   

6.
Twenty-four Suffolk x Hampshire ram lambs (average 46 kg) were assigned to one of three diets containing rapeseed meal (RM), soybean meal (SBM), or whole rapeseed-soybean meal (RSSBM) as the protein source. Diets contained 75% roughage, 14% CP and 2.0 Mcal of ME/kg and lambs were allowed ad libitum access to diets for 35 d. Lipid composition of the longissimus, semimembranosus, and triceps brachii muscles and their corresponding s.c. adipose tissue was determined by gas-liquid chromatography (GLC). The total lipid content in either muscle or subcutaneous fat was not different (P greater than .01) by diet. In lean tissue, palmitic and palmitoleic acids were higher and stearic acid was lower (P less than .01) in rams fed RM than in rams fed RSSBM or SBM, regardless of anatomical location. In the s.c. adipose tissue, the amounts of myristoleic, pentadecylic, and palmitoleic acids were lower and the amount of stearic acid was higher (P less than .01) in rams fed RSSM than in those fed RM or SBM, regardless of anatomical location. The semimembranosus and triceps brachii muscles from all treatments contained 12 to 19% more polyunsaturated fatty acids (PUFA) than the longissimus muscle. The cholesterol content of the three muscles was highest in SBM-fed lambs, lowest in RM-fed lambs, and intermediate in RSSBM-fed lambs. These results demonstrate that dietary treatments of the types used in the present study elicit changes in fatty acid composition of both adipose and muscle tissue without affecting the quantity of total lipid.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

7.
Three-year-old Angus x Gelbvieh beef cows, which were nutritionally managed to achieve a BCS of 4 +/- 0.07 (479 +/- 36 kg of BW) or 6 +/- 0.07 (580 +/- 53 kg of BW) at parturition, were used in a 2-yr experiment (n = 36/yr) to determine the effects of maternal BCS at parturition and postpartum lipid supplementation on fatty acid profile of suckling calf plasma and adipose tissue. Beginning 3 d postpartum, cows within each BCS were assigned randomly to 1 of 3 treatments in which cows were all fed hay and either a low-fat (control) supplement or supplements with either high-linoleate cracked safflower seeds (linoleate) or high-oleate cracked safflower seeds (oleate) until d 61 of lactation. Diets were formulated to be isonitrogenous and isocaloric, and safflower seed supplements were provided to achieve 5% of DMI as fat. Total concentration of fatty acids in plasma did not differ (P = 0.48) due to maternal BCS at parturition. Percentage of 20:5n-3 in plasma tended (P = 0.06) to be greater for calves suckling cows with a BCS of 6 at parturition. No other differences (P = 0.12 to 0.99) were noted in calf plasma fatty acid profile due to maternal BCS at parturition. Likewise, no differences were detected for total fatty acid concentration (P = 0.88) in calf adipose tissue due to maternal BCS at parturition. Weight percentage of 14:1 (P = 0.001) was greatest in adipose tissue of calves suckling cows fed control and oleate; however, the percentages of 14:0, 15:0, 16:0, 16:1, 17:0, and 18:3n-3 were greater (P < 0.001) in adipose tissue from calves suckling cows fed control compared with calves suckling cows fed linoleate or oleate. Percentages of 18:0, 18:1trans-11, 18:2n-6, and cis-9, trans-11 CLA were greater (P < 0.001) in adipose tissue from calves suckling cows fed linoleate compared with calves suckling cows fed control and oleate. Calves suckling cows fed oleate had greater (P < 0.001) percentages of 18:1trans-9, 18:1trans-10, and 18:1cis-9 in adipose tissue than calves suckling cows fed control or linoleate. Calf plasma and adipose tissue fatty acid profiles were reflective of milk fatty acids. Because fatty acids play an important role in metabolic regulatory functions, changes in milk fatty acid profile should be considered when beef cows are fed lipid supplements.  相似文献   

8.
Fatty acid composition of total lipid extracts of muscle and adipose samples from crossbred bulls (N = 34) and steers (N = 35) was determined by gas-liquid chromatography. Samples of semitendinosus, triceps brachii and longissimus muscle and of subcutaneous and perinephric adipose tissue were excised from the right side of each carcass. In addition, thin-layer chromatography was utilized to obtain phospholipid and triacylglycerol fractions from total lipid extracts of semitendinosus and longissimus muscle and subcutaneous adipose tissue from 10 bull and steer cohorts (N = 20). The most prominent sex condition effect was in percentage of total poly-unsaturated fatty acids (PUFA). Bull tissues contained higher (P less than .01) percentages of PUFA than those of steers at all sampling sites. This reflected higher percentages of linoleate (C18:2), linolenate (C18:3) and arachidonate (C20:4) in bull tissues. Most of the PUFA were present as phospholipids in muscle samples. The fatty acid composition of muscle phospholipids was similar regardless of sex condition or muscle sampled. Total lipid extracts of semitendinosus and triceps brachii muscles of both bulls and steers contained from 6 to 10% more unsaturated fatty acids (UFA) compared with M. longissimus. Muscle triacylglycerols contained relatively high percentages of saturated fatty acids (SFA). Semitendinosus and longissimus samples from steers contained higher (P less than .05 and P less than .01, respectively) percentages of total SFA than those from bulls. Steer samples contained slightly higher percentages of palmitic acid (C16:0) compared with bulls at all sampling sites, and this difference was significant for M. longissimus. The fat:lean ratio of muscle tissue is the major factor that determines fatty acid composition.  相似文献   

9.
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   

10.
The objective of this study was to determine whether increasing levels of dietary safflower oil would alter unsaturated fat (especially CLA) and tocopherol content of lamb, animal performance, carcass characteristics, or color stability of lamb muscle tissue. Targhee x Rambouillet wethers (n = 60) were assigned to one of three diets (four pens per treatment with five lambs per pen) in a completely random design. Diets were formulated with supplemental safflower oil at 0 (control), 3, or 6% (as-fed basis) of the diet. Diets containing approximately 80% concentrate and 20% roughage were formulated, on a DM basis, to be isocaloric and isonitrogenous and to meet or exceed NRC requirements for Ca, P, and other nutrients. A subsample of 12 wethers per treatment was selected based on average BW (54 kg) and slaughtered. Carcass data (LM area, fat thickness, and internal fat content) and wholesale cut weight (leg, loin, rack, shoulder, breast, and foreshank), along with fatty acid, tocopherol, and color analysis, were determined on each carcass. The LM and infraspinatus were sampled for fatty acid profile. Increasing safflower oil supplementation from 0 to 3 or 6% increased the proportion of linoleic acid in the diet from 49.93 to 55.32 to 62.38%, respectively, whereas the percentage of oleic acid decreased from 27.94 to 23.80 to 20.73%, respectively. The percentage of oil in the diet did not (P > or = 0.11) alter the growth and carcass characteristics of lambs, nor did it alter the tocopherol content or color stability of meat. Increasing levels of safflower oil in lamb diets decreased (P < 0.01) the weight percentage of oleic acid in the infraspinatus and LM, and increased linoleic acid (P < 0.01). Oil supplementation increased (P < 0.01) the weight percentage of various isomers of CLA in muscle, with the greatest change in the cis-9,trans-11 isomer. Supplementation of sheep diets with safflower oil, up to 6% of the diet, resulted in increasing levels of unsaturated fatty acids and CLA in the lean tissue, without adversely affecting growth performance, carcass characteristics, or color stability of lamb.  相似文献   

11.
To provide further insights into ruminant lipid digestion and metabolism, and into cis-9,trans-11 18:2 synthesis, 12 growing Engadine lambs grazing either mountain pasture (2,250 m above sea level; n = 6) or lowland pasture (400 m above sea level; n = 6) were studied. Both pastures consisted exclusively of C(3) plants. Before the experiment, all animals grazed a common pasture for 6 wk. Grasses and perirenal adipose tissues of the sheep were analyzed for fatty acids by gas chromatography. Stable C-isotope ratios (δ(13)C values in ‰ vs. the Vienna Pee Dee Belemnite standard) were determined in the composite samples by elemental analysis-isotope ratio mass spectrometry. The δ(13)C of the individual fatty acids were measured by gas chromatography-combustion-isotope ratio mass spectrometry. The δ(13)C value of the entire mountain pasture grass was -27.5‰ (SD 0.31), whereas that of the lowland pasture grass was -30.0‰ (SD 0.07). This difference was reflected in the perirenal adipose tissues of the corresponding sheep (P < 0.05), even though the δ(13)C values were less in the animals than in the grass. The δ(13)C values for cis-9 16:1 and cis-9 18:1 in perirenal fat differed between mountain and lowland lambs (P < 0.05). The 16:0 in the adipose tissue was enriched in (13)C by 5‰ compared with the dietary 16:0, likely as a result of partly endogenous synthesis. The δ(13)C values of cis-9,trans-11 18:2 (cis-9,trans-11 CLA) in the adipose tissue were smaller than those of its dietary precursors, cis-9,cis-12 18:2 and cis-9,cis-12,cis-15 18:3; conversely, the δ(13)C values of trans-11 18:1 were not, suggesting that large proportions of perirenal cis-9,trans-11 18:2 were of endogenous origin and discrimination against (13)C occurred during Δ(9)-desaturation. The same discrimination was indicated by the isotopic shift between 16:0 and cis-9 16:1 in the mountain grazing group. Furthermore, the δ(13)C values of cis-9,trans-11 18:2 were smaller relative to the precursor fatty acids in the mountain lambs compared with the lowland group. This result suggests a reduced extent of biohydrogenation in lambs grazing on mountain grass in comparison with those grazing on lowland grass. This was supported by the smaller cis-9,trans-11 18:2 concentrations in total fatty acids found in the adipose tissues of the lowland lambs (P < 0.001). The results of this study demonstrate that natural differences between δ(13)C values of swards from different pastures and the adipose tissue fatty acids could be used as tracers in studies of lipid metabolism in ruminants.  相似文献   

12.
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   

13.
Three grazing experiments were conducted to determine the effect of level of endophyte infection, rate of N fertilization of tall fescue grass, grazing period, and paddock exchange on selected chemical properties of four bovine carcass tissues. Samples of semitendinosus and longissimus muscle and of subcutaneous and perinephric adipose tissue were excised from the left side of each carcass. In Exp. 1, percentage of stearic acid was higher (P less than .05) and percentages of palmitoleic and oleic acid were lower (P less than .05) in all tissues from steers grazed on LELN Au-Triumph fescue than in tissues from steers grazed on LELN KY-31 fescue. Grazing periods of 175 or 245 d or paddock exchange (Exp. 2) had no significant effect on proximate composition of semitendinosus and longissimus muscles; however, moisture content was higher (P less than .05) in the semitendinosus muscle from steers grazed on 100% (100E) endophyte-infected KY-31 fescue. Forage treatment, grazing period, and paddock exchange (Exp. 2 and 3) had no significant effect on percentage of saturated fatty acids in the subcutaneous, semitendinosus, and longissimus tissue samples. In Exp. 2 and 3, percentages of saturated fatty acids were higher (P less than .05) in subcutaneous and perinephric adipose tissue samples from steers grazed on 100E than in samples from steers grazed on zero endophyte (OE) fescue.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
Feeding sheep concentrate-based diets increases the oleic acid content of their tissues, whereas the cis-9, trans-11 conjugated linoleic acid (CLA) content is increased by feeding forage diets. Both these metabolic transformations could be attributable to increased activity of stearoyl-CoA desaturase (SCD). Therefore, the effect of forage or concentrate feeding regimens on the fatty acid composition of sheep tissues were investigated to determine whether any changes are related to an alteration of SCD mRNA levels. Twenty-four ewe lambs were randomly allotted to one of three dietary treatment groups: 1) dehydrated grass pellets, 2) concentrate diet fed to achieve a growth rate similar to that of the dehydrated grass pellets, and 3) the same concentrate diet approaching ad libitum intake. As expected, animals fed ad libitum concentrates grew at a greater (P = 0.001) rate (280 g/d) than those fed either of the other two diets (180 g/d), which were similar. In samples of liver and the three adipose tissue depots studied, the concentration of oleic acid from sheep fed either level of the concentrate diet was greater (P < 0.001) than from animals fed forage. This was associated with an increase (P < 0.05) in the ratio of SCD to acetyl-CoA carboxylase mRNA in adipose tissue and liver. Compared with concentrate-fed, the forage-fed lambs had increased (P < 0.05) levels of the cis-9, trans-11 isomer of CLA and C18:1, trans-11 in all their tissues, although the levels of SCD mRNA were lower. It therefore seems that the increased oleic acid content of sheep tissues in response to concentrate-rich diets is associated with an increase in SCD gene expression. By contrast, the increased concentration of CLA in animals fed forage-based diets is associated with an increase in substrate (C18:1 trans-11) availability.  相似文献   

15.
The objective of this research was to determine the influence of dietary palm oil supplementation on carcass characteristics and lipid composition of tissues from growing lambs. Twenty-eight Suffolk x Hampshire lambs were weaned at 60 d of age (average 36 kg BW) and assigned to a 2 x 2 factorial arrangement consisting of diet (control [NPO] or 10.6% added dietary palm oil [PO]) and sex (ram vs ewe). The NPO diet (77% forage and 23% concentrate) contained 11.2% CP and 2.66 Mcal of ME/kg. Palm oil replaced molasses in the PO diet. Lambs were individually given ad libitum access to feed for 60 d to a final BW average of 50.1 kg. Lipid composition of the longissimus muscle and corresponding subcutaneous (s.c.) adipose tissue was determined by gas-liquid chromatography (GLC). Lambs fed PO were fatter (P less than .01) than lambs fed NPO (.77 vs .56 cm, s.c. fat). Diet had no effect on cholesterol content of lean tissue; however, feeding PO increased the saturated fatty acids of lean tissue. The s.c. fat from lambs fed PO had less (P less than .01) cholesterol (64.79 vs 89.67 mg/100 g) and more saturated fatty acids than that from lambs fed NPO. Ewes were fatter (P less than .01) than rams, yet they had less cholesterol content in the s.c. adipose tissue (68.71 vs 85.74 mg/100 g). High amounts of dietary palm oil fed to growing lambs caused changes in fatty acid deposition and cholesterol metabolism and may be a useful investigative tool to study lipid metabolism in growing ruminants.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

16.
Lambs from rams (R), cryptorchids (C) and wethers (W) were examined to compare with the dietary guidelines for humans on fat and cholesterol intake. Twenty-four lambs were assigned to treatments as R, C or W at weaning (60 d). Each lamb had ad libitum access to a 77:23% forage:concentrate diet containing 11.7% crude protein and 1.84 Mcal ME/kg. The experiment was terminated when the lambs reached 50 kg body weight. Lipid composition of the longissimus muscle (LM) and s.c. adipose tissue was determined by gas-liquid chromatography. Rams has less (P less than .01) s.c. fat (cm) and i.m. lipid (%) (.26 cm; 3.*%) than W (.56 cm; 4.9%). Total polyunsaturated fatty acids were greater (P less than .01) in the LM of R (7.06%) than in LM of W (5.21%). Rams had higher percentages of C18:2, C18:3, C20:4 and C18:1 in their LM than W did. On the basis of a 100-g serving of LM, R had 1.73, C had 2.15 and W had 2.21 g saturated fatty acids. There were no (P less than .01) differences among sex types for cholesterol content of LM, which averaged 66.6 mg/100 g wet tissue. The only major difference of the s.c. fat lipid composition was in saturated fatty acids. Wethers had higher (P less than .01) saturated fatty acids (51.4%) than C 46.8%) and R (43.3%). Based on the lipid composition of these three types of lambs, the LM muscle from young R lambs approached dietary fat guidelines for humans more closely than did that from castrates.  相似文献   

17.
The objective of this study was to compare fatty acid weight percentages and cholesterol concentrations of longissimus dorsi (LD), semitendinosus (ST), and supraspinatus (SS) muscles (n = 10 for each) of range bison (31 mo of age), feedlot-finished bison (18 mo of age), range beef cows (4 to 7 yr of age), feedlot steers (18 mo of age), free-ranging cow elk (3 to 5 yr of age), and chicken breast. Lipids were analyzed by capillary GLC. Total saturated fatty acids (SFA) were greater (P < 0.01) in range bison than in feedlot bison and were greater (P < 0.01) in SS of range beef cattle than in feedlot steers. Muscles of elk and range bison were similar (P > 0.05) in SAT. In LD, polyunsaturated fatty acids (PUFA) were highest (P < 0.01) for elk and range bison and lowest (P < 0.01) for feedlot steers within each muscle. Range bison and range beef cows had greater (P < 0.01) PUFA in LD and ST than feedlot bison or steers, respectively. Range-fed animals had higher (P < 0.01) n-3 fatty acids than feedlot-fed animals or chicken breast. Chicken breast n-6 fatty acids were greater (P < 0.01) than for muscles from bison, beef, or elk. Elk had higher (P < 0.01) n-6 fatty acids than bison or beef cattle; however, range-fed animals had higher (P < 0.01) n-6 fatty acids than feedlot-fed animals in ST. Conjugated linoleic acid (CLA, 18:2cis-9, trans-11) in LD was greatest (P < 0.01) for range beef cows (0.4%), and lowest for chicken breast and elk (mean = 0.1%). In ST, CLA was greatest (P < 0.01) for range and feedlot bison and range beef cows (mean = 0.4%) and lowest for elk and chicken breast (mean = 0.1%). Also, SS CLA was greatest (P < 0.01) for range beef cows (0.5%) and lowest for chicken breast (0.1%). Mean total fatty acid concentration (g/100 g tissue) for all muscles was highest (P < 0.01) for feedlot bison and feedlot cattle and lowest (P < 0.01) for range bison, range beef cows, elk, and chicken. Chicken breast cholesterol (mg/100 g tissue) was higher (P < 0.01) than LD and ST cholesterol, which were lowest (P < 0.01; 43.8) for range bison and intermediate for the other species. Cholesterol in SS was highest (P < 0.01) for feedlot bison and steers, which were similar to chicken breast (mean = 61.2 vs 52.8 for the mean of the other species). We conclude that lipid composition of bison muscle varies with feeding regimen, and range-fed bison had muscle lipid composition similar to that of forage-fed beef cows and wild elk.  相似文献   

18.
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   

19.
Beef knuckles (n = 160) were obtained from source-verified cattle finished on 30% wet distillers grains plus solubles enriched with varying levels of alfalfa hay (4 or 8%), corn silage (6 or 12%), or corn stalks (3 or 6%) based on NDF. Proximate analysis, pH, oxidation-reduction potential, fatty acid composition, and sensory analysis were conducted on the rectus femoris muscle to determine if roughage inclusion, in conjunction with wet distillers grains plus solubles and cattle source, affects beef flavor with particular interest in liver-like off-flavor. Proximate analysis, fat content, and oxidation-reduction potential were unaffected (P ge;0.129) by diet or source. For s.c. adipose tissue, cattle from Nebraska (NE) had greater amounts of MUFA (P = 0.048) and unsaturated fatty acids (P = 0.068) but less SFA (P = 0.065) when compared with cattle from South Dakota. Diet affected s.c. adipose tissue levels of 15:0, 17:0, and n-3 fatty acids in which cattle from NE finished on the low corn stalk diet had (P < or =0.050) lower levels. Cattle from NE had (P < or = 0.049) greater i.m. adipose proportions of 13:0 and CLA. Dietary effects (P < or = 0.050) were observed for i.m. adipose tissue proportions of 16:0, 18:1(n-9), 18:2(n-6), 20:4(n-6), 22:5(n-3), MUFA, PUFA, and n-6 fatty acids. Sensory analysis revealed that cattle from NE were (P < or = 0.023) less juicy and had less bloody notes when compared with cattle from South Dakota. Cattle finished on the low alfalfa diet were (P < or = 0.014) more tender and juicy but had more bloody notes. No (P ge; 0.670) dietary or source effects were noted for liver-like off-flavor. Subcutaneous amounts of 18:2(n-6 trans) (r = -0.17) were inversely related to the incidence of liver-like off-flavor, whereas 20:1(n-9) (r = 0.21), CLA cis-9, trans-11 (r = 0.16) were directly related. Data from this study indicate that type and level of roughage inclusion and cattle source have minimal effects on fatty acid profiles and sensory properties of the musculus rectus femoris. However, individual fatty acids of s.c. and i.m. adipose tissue were significantly correlated with liver-like off-flavor.  相似文献   

20.
Conjugated linoleic acid (CLA) has been shown to have an effect on subcutaneous fatty acid composition and has been reported to decrease stearoyl coenzyme A desaturase (SCD) activity by decreasing mRNA expression and(or) catalytic activity in rodents and rodent cell lines. This investigation was designed to study the effects of CLA, corn oil, or beef tallow supplementation on s.c. adipose tissue fatty acid composition, adiposity, SCD enzyme activity, and the delta9 desaturase index in piglets. Eighteen crossbred barrows 16 to 18 d of age were adapted to diet for 1 wk and then assigned randomly to one of three treatments: 1.5% added CLA, 1.5% added corn oil, or 1.5% added beef tallow. Barrows were penned individually and fed the supplemental oils for 35 d (to 25.6 +/- 0.6 kg BW). Subcutaneous adipose tissue samples were obtained after slaughter. Fatty acid composition of the s.c. adipose tissue differed for each fatty acid measured due to diet with the exception of 18:3. The concentrations of CLA trans-10, cis-12 and cis-9, trans-11 were elevated from nondetectable to 1.62 and 2.52 g/100 g lipid, respectively (P < 0.001 for both isomers). Conjugated linoleic acid decreased the delta9 desaturase index (P < 0.01) and SCD enzyme activity, expressed as nanomoles of palmitate converted to palmitoleate/(7 min x g of tissue) (P = 0.075) and nanomoles of palmitate converted to palmitoleate/(7 min 105 cells) (P= 0.056). Tallow-fed pigs had a greater proportion of large adipocytes (> 700 pL) and the greatest SCD activity. These data provide the first direct evidence that dietary CLA depresses SCD enzyme activity in porcine adipose tissue, which may in part be responsible for the depression of adiposity by CLA observed by others in market weight pigs.  相似文献   

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