Effects of dietary vitamin and fatty acid content in E on muscle vitamin E Aohan fine-wool sheep

Background： Increasing the polyunsaturated fatty acid （PUFA） content and decreasing the saturated fatty acid （SFA） content of mutton can help to improve its nutritional value for consumers. Several laboratories have evaluated the effects of vitamin E on the fatty acid （FA） composition of muscle in sheep. However, little information is available on wool sheep, even though wool sheep breeds are an important source of mutton, especially in northern China where sheep are extensively farmed. The present study was designed to address the effects of vitamin E on muscle FA composition in male Aohan fine-wool sheep. Methods： Forty-two male Aohan fine-wool lambs （5 mo old） with similar initial body weight were randomly divided into seven groups and fed diets supplemented with 0 （control group）, 20, 100, 200, 1,000, 2,000, or 2,400 IU/sheep/d vitamin E for 12 mo. Three lambs from each group were slaughtered to measure vitamin E and FA content in the Iongissimus lumborum （LL） and gluteus medius （GM） muscles. Results： Vitamin E concentrations in the LL and GM increased significantly after 12 mo of vitamin E supplementation （P 〈 0.05）. However, this increase did not occur in a dose-dependent manner because the muscle vitamin E concentration was highest in the 200 IU/sheep/d group. Dietary vitamin E supplementation also caused a significant reduction in SFA content and an increase in monounsaturated FA （MUFA） content in the LL and GM （P 〈 0.05）. All six doses of vitamin E significantly increased cis9 tronsl -conjugated linoleic acid （cgtl -CLA） content in the LL compared with the control group （P 〈 0.05）. Conclusions： Dietary supplementation with vitamin E increased muscle vitamin E content and improved the nutritional value of mutton by decreasing SFA content and increasing MUFA and c9tl 1-CLA contents in Aohan fine-wool sheep. These effects were greatest in sheep fed a diet containing 200 IU/sheep/d vitamin E.     

Subcutaneous fatty acid composition of steers finished as weanlings or yearlings with and without growth promotants

Background: The current study evaluated the subcutaneous fatty acid(FA) composition of calf- and yearling-fed stee with or without growth promoting implants. Crossbred steers(n = 112; 267 ± 5.0 kg) of the same contemporary group were allocated to one of four production system and implant strategy based treatments in a completely randomized design with a 2 × 2 factorial arrangement of treatments.Results: There were no interactions(P 0.05) between production systems and growth promoting implants for the total and individual subcutaneous FA. Yearling as opposed to calf finishing reduced(P 0.05) subcutaneous proportions of C20:3n-6, trans(t)12-18:1, C14:0, several minor cis-monounsaturated FA(c-MUFA; c9-14:1, c11-16:1,c11-18:1, c12-18:1, c13-18:1, c9-20:1 and c11-20:1), and increased(P 0.05) subcutaneous proportions of t11c15-18:2,total and individual branched-chain FA. Subcutaneous fat from steers implanted with growth promotants had higher(P 0.05) proportions of total polyunsaturated FA(PUFA), total n-6 PUFA, C18:2n-6 and individual t-18:1isomers(t6 to t10) compared to non-implanted steers.Conclusions: Overall, current findings show that production systems and growth promotants led to only minor differences in subcutaneous FA composition of beef steers.     

猪肌内脂肪酸成分的研究进展

脂肪酸成分在猪的育种上是一个重要的经济性状,不仅影响猪肉品质,而且对人类的健康也有十分重要的作用。本文综述了近几年来国内外学者在猪肌内脂肪酸成分方面的研究进展。     

Effects of ensiling processes and antioxidants on fatty acid concentrations and compositions in corn silages

Background： Corn silage is the main dietary component used for ruminant breeding in China and is an important dietary source of fatty acids for these animals. However, little is known regarding effective means to protect the fatty acid （FA） contents in silages. In this study, we examined the changes in FA contents and compositions during corn ensiling and screened several antioxidants for their inhibition of lipid oxidation during corn ensiling. Methods： We conducted two different experiments. In Experiment 1, corn was ensiled in 30 polyethylene bottles （bottle volume： 1 L, silage density： 600 g/dm3） and three bottles were opened at 0.5 d, 1 d, 1.5 d, 2 d, 2.5 d, 3 d, 5 d, 7 d, 14 d, and 28 d after ensiling. In Experiment 2, corn was treated with various antioxidants： （1） No additives （CK）; （2） BHA （Butylated hydroxyanisole）; （3） TBHQ （Tertiary butyl hydroquinone）; （4） TPP （Tea polyphenols）; and （5） VE （Vitamin E）. These treatments were applied at 50 mg/kg and 100 mg/kg of fresh weight with each treatment replicated 3 times. Results： During ensiling in Experiment 1, saturated fatty acids （SFA; C16：0 and C18：0） and malondialdehyde （MDA） contents tended to increase, whereas unsaturated fatty acids （UFA; C18：1, C18：2 and C1 8：3） tended to decrease. However, these changes were only significant on the first 2 days of ensiling. In Experiment 2, all of the antioxidants tested affected the total FA contents and those of unsaturated fatty acids （C1 8：1, C18：2 and C18：3） and MDA. The effects of TBHQ and TPP were greater than those of the other antioxidants. Conclusions; The reduced total FA contents in corn silages were due to unsaturated fatty acids＇ oxidation during the early stages of ensiling. Adding an antioxidant could prevent fattv acids＇ oxidation in corn silages.     

Effectiveness of short-term feeding strategies for altering conjugated linoleic acid content of beef

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.     

Effects of breed type and restricted versus ad libitum feeding on fatty acid composition and cholesterol content of muscle and adipose tissue from mature bovine females

Fatty acid composition and cholesterol content of muscle and adipose tissue from mature cows (N = 101) representing 15 breeds and crosses were determined. An initial group of cows was slaughtered after being fed slightly above the maintenance level for 2 wk; the remaining cows were fed either at the maintenance level or ad libitum for 84 d, then slaughtered. Samples of triceps brachii and longissimus muscle and subcutaneous and perinephric adipose tissue were obtained from each carcass. In addition, phospholipid and triacylglycerol fatty acids from total lipid extracts of triceps brachii muscle and subcutaneous adipose tissue were analyzed for 24 cows that were fed ad libitum or at the maintenance level for 84 d. Breed type effects on fatty acid composition were more pronounced in adipose tissue than in muscle tissue. Total lipid extracts of both triceps brachii and longissimus muscle from animals fed a maintenance diet for 84 d contained higher (P less than .01) percentages (3 to 8%) of polyunsaturated fatty acids (PUFA) and lower percentages (2 to 3%) of saturated fatty acids (SFA) than those from animals fed ad libitum for 84 d. This reflected significant variation in the fatty acids C14:0, C16:0, C18:2, C18:3 and C20:4 for both longissimus and triceps brachii muscle. Fatty acid composition within phospholipid and triacylglycerol fractions was similar regardless of maintenance or ad libitum feeding. Much of the variation in total lipid fatty acid composition appeared to be the result of differences in triacylglycerol:phospholipid ratios. Adipose tissue contained about twice as much cholesterol (mg/100 g wet weight) as muscle tissue. Both breed type and feeding group effects on cholesterol content of muscle tissue were nonsignificant. Values for cholesterol content of adipose tissue from cows fed restricted diets were higher than those from cows fed ad libitum (approximately 55 mg/100 g higher for subcutaneous and 25 mg/100 g for perinephric). The results show that changes in fatty acid composition of bovine tissues can be made genetically and by varying the energy level in the diet. Alteration of the cholesterol content of muscle tissue by these methods does not appear to be feasible.     

Effect of DNA polymorphisms related to fatty acid composition in adipose tissue of Holstein cattle

Fatty acid composition of adipose tissue has been recognized as an important carcass trait because of its relationship with eating quality such as favorable beef flavor and tenderness. Therefore, we investigated the effects of genetic polymorphisms of liver X receptor, alpha (LXR), stearoyl‐CoA desaturase (SCD), Fatty acid synthase (FASN), and Fatty acid binding protein 4 (FABP4) on fatty acid composition in intramuscular fat tissue of Holstein steers. The major allele frequencies were 0.705 in SCD, 0.518 in FABP4, 0.888 in FASN, and 0.984 in LXR. Genotyping of SCD showed significant effect on C14:0, C14:1, C18:0 and saturated fatty acid (P < 0.05). In addition, the result suggested that SCD genotype possibly had effect on composition of C18:1 and monounsaturated fatty acid. Genotype of FABP4 had significant effect on composition of C16:0. Effect of LXR genotypes could not be analyze because of extremely biased genotype frequencies. Our results suggest that genotypes of SCD and FABP4 may in part affect meat quality in Holstein.     

Effect of dietary vitamin A concentration and roasted soybean inclusion on marbling, adipose cellularity, and fatty acid composition of beef

A feedlot trial was conducted to determine the effect of dietary vitamin A concentration and roasted soybean (SB) inclusion on carcass characteristics, adipose tissue cellularity, and muscle fatty acid composition. Angus-crossbred steers (n = 168; 295 +/- 1.8 kg) were allotted to 24 pens (7 steers each). Four treatments, in a 2 x 2 factorial arrangement, were investigated: no supplemental vitamin A, no roasted soybeans (NANS); no vitamin A, roasted SB (20% of the diet on a DM basis; NASB); with supplemental (2,700 IU/kg) vitamin A, no roasted SB (WANS); and with supplemental vitamin A, roasted SB (WASB). Diets included high moisture corn, 5% corn silage, 10 to 20% supplement, and 20% roasted SB in the SB treatments on a DM basis. The calculated vitamin A concentration in the basal diet was < 1,300 IU/kg of DM. Blood samples (2 steers/pen) were collected for serum vitamin A determination. Steers were slaughtered after 168 d on feed. Carcass characteristics and LM composition were determined. Fatty acid composition of LM was analyzed, and adipose cellularity in the i.m. and s.c. depots was determined. No vitamin A x SB interactions were detected (P > 0.10) for cattle performance, carcass composition, or muscle fatty acid composition. Low vitamin A diets (NA) did not affect (P > 0.05) ADG, DMI, or G:F. Quality grade tended (P = 0.07) to be greater in NA steers. Marbling scores and the percentage of carcasses grading > or = Choice(-) were 10% greater for NA steers, although these trends were not significant (P = 0.11 and 0.13, respectively). Backfat thickness and yield grade were not affected (P > 0.26) by vitamin A supplementation. Composition of the LM was not affected (P > 0.15) by vitamin A or SB supplementation. Serum retinol at slaughter was 44% lower (P < 0.01) for steers fed NA than for steers supplemented with vitamin A (23.0 vs. 41.1 microg/dL). A vitamin A x SB interaction occurred (P < 0.05) for adipose cellularity in the i.m. depot; when no SB was fed, vitamin A supplementation decreased cell density and increased cell size. However, when SB was fed, vitamin A supplementation did not affect adipose cellularity. Adipose cellularity at the s.c. depot was not affected (P > 0.18) by vitamin A or SB treatments. Fatty acid profile of the LM was not affected by vitamin A (P > 0.05), but SB increased (P < 0.05) PUFA (7.88 vs. 4.30 g/100 g). It was concluded that feeding NA tended to increase marbling without affecting back-fat and yield grade. It appeared that NA induced hyperplasia in the i.m. but not in the s.c. fat depot.     

UTS2R gene polymorphisms are associated with fatty acid composition in Japanese beef cattle

Fatty acid composition of beef adipose tissue is one of its important traits because a high proportion of monounsaturated fatty acid is related to favorable beef flavor and tenderness. In this study, we searched polymorphisms in full length coding DNA sequence of urotensin 2 recepter and investigated the effects on fatty acid composition (C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, monounsaturated fatty acid, saturated fatty acid). Eight single nucleotide polymorphisms (SNP) were identified by sequence comparison among eight animals, including five Japanese Black and three Holstein cattle. One of these SNP (c.866C>T) was predicted to cause amino acid substitutions (P289L) and the other seven synonymous SNP, including c.267C>T, were presumed to be in linkage disequilibrium. Therefore we selected two SNP (c.267C>T and c.866C>T) for further analysis. We investigated associations between these genotypes and fatty acid composition in three Japanese Black populations (n = 560, 245 and 287) and a Holstein population (n = 202). Tukey‐Kramer's honestly significant difference test revealed that CC genotype in c.267C>T indicated lower C14:0 and higher C18:1 than the other genotypes in Japanese Black cattle and CC genotype in c.866C>T showed lower C16:1 than CT genotype in Holstein cattle (P < 0.05). These results suggested that these genotypes would contribute to production of high‐grade meat as selection markers in beef cattle.     

Evaluation of FABP2 as candidate gene for a fatty acid composition QTL in porcine chromosome 8

The objective of this work was to analyse the porcine Fatty acid binding protein 2, intestinal ( FABP2 ) gene as a candidate gene for a fatty acid composition quantitative trait loci (QTL) previously described on porcine chromosome 8 in an Iberian by Landrace F₂ cross (IBMAP). Re-sequencing of the porcine FABP2 gene in three Iberian and eight Landrace parental animals resulted in the identification of three single-nucleotide polymorphisms, all of them localized in intron 1. The polymorphism FABP2 :g.412T>C, localized in intron 1, and two additional microsatellites were genotyped in the IBMAP population in order to perform an association test of the FABP2 gene and to better define the QTL position previously described. Association analyses of the FABP2 :g.412T>C with the fatty acid composition traits were not significant in simple association and marker-assisted association tests, suggesting that the FABP2 region sequenced is not responsible for the QTL. However, the addition of three new markers to the pedigree allowed us to define the S0144–SW61 marker interval as the most likely QTL position, facilitating the future study of other candidate genes for this QTL.     

Influence of Montmoriilonite Nanocomposite on Tissue Levels of Lead and Blood Biochemical Parameters in Pigs Exposed to Lead1

ABSTRACT： Eighteen （Duroc x Landrace x Yorkshire） castrated boars, 55 days of age and weig- hing approximately 19 kg, were used to investigate the effects of montmorillonite nanocomposite on tissue levels of lead as well as changes in blood biochemical parameters in pigs fed lead contaminated diets. The barrows were randomly assigned to one of three treat- ments （n = 6） including a control which were fed a basal diet based on corn and soybean meal. The re- maining two groups were fed the basal diet supple- mented with 10 mg/kg lead either with or without 0.5% montmorillonite nanocomposite for 50 days. Pigs treated with lead had significantly increased lev- els of lead in their tissues. Lead accumulated in all tis- sues of the body with the highest accumulation found in the hair. When montmorillonite nanocomposite was given along with lead, tissue concentrations of lead did not differ from the control. Fecal excretion of leadincreased significantly in lead-exposed pigs treated with montmorillonite nanocomposite. A progressive and appreciable accumulation of lead was seen in blood with a concomitant increase in zinc protopor- phyrin levels during the course of treatment. Howev- er, zinc protoporphyrin levels did not differ from the control when montmorillonite nanocomposite was ad- ministered along with lead. The activity of ~-amino le- vulinic acid dehydratase in blood was significantly in- creased in lead treated pigs compared with the con- trol. However, in pigs treated with lead and montmo- riltonite nanocomposite in combination, the activity of δ-amino levulinic acid dehydratase was similar to con- trol pigs. Our results indicate that montmorillonite nanocomposite treatment of pigs exposed to lead re- suited in reduced lead concentrations in body tissues. It appears that montmorillonite nanocomposite func- tions by increasing fecal excretion of lead.     

Effects of dietary sunflower seeds and tylosin phosphate on production variables, carcass characteristics, fatty acid composition, and liver abscess incidence in crossbred steers

A 2 x 2 factorial experiment with 48 crossbred steers (with Hereford, Angus, and Charolais genetics, and an initial BW of 373 +/- 8.4 kg) was conducted to evaluate the effects of dietary sunflower seeds (SS) and tylosin phosphate (TP) on production factors, carcass characteristics, liver abscess incidence, and fatty acid composition of the muscle (pars costalis diaphragmatis; PCD) and subcutaneous fat. Individually penned steers were fed either a control diet of 84.5% rolled barley, 14% barley silage, and 1.5% mineral and vitamin mix on a DM basis, or an SS diet, in which SS replaced 15% of the diet. Half the animals fed each diet received TP at 11 mg/kg of DM as a top dressing. Interactions were significant for all production factors. A reduction (P = 0.008) in DMI was observed from 10.1 +/- 0.4 kg/d, in steers fed the control diet, to 8.9 +/- 0.3 and 8.6 +/- 0.3 kg/d, in steers fed the SS and SS + TP diets, respectively. Greater (P = 0.014) ADG was observed for steers fed the control diet than for those fed the SS or SS + TP diet (1.4 vs. 1.1 and 1.2, SE = 0.1 kg/d, respectively); however, G:F ratios were greater (P = 0.011) in steers fed the control diets than in those fed the SS diets. Steers fed the control and SS diets had the heaviest and lightest HCW (347 +/- 6.9 vs. 325 +/- 8.4 kg; P = 0.025), respectively. Lean meat yield (%) of steers fed SS was greater (P = 0.117) than in steers fed the control diets, whereas total lean yield [(HCW x lean meat yield)/100] was similar (P = 0.755). Provision of the SS or SS + TP diet eliminated (P = 0.08 for interaction) liver abscesses compared with the 36 and 9% incidence in steers fed the control or control + TP diet, respectively. Fatty acid weight percentages (wt%) followed similar patterns in PCD and subcutaneous fat. Feeding the SS diets led to greater (P = 0.001) wt% of 18:0 and 18:2n-6, but reduced the wt% of 16:0, 9-cis (c)-18:1, and 18:3n-3 in PCD compared with that in steers fed the control diets, but the wt% of 9c,11-trans (t), and 10t,12c CLA were increased (P = 0.001) by 36 and 400% in PCD. Dietary SS increased (P < 0.001) the wt% of trans-18:1 isomers. The 10t-18:1 and 11t-18:1 isomers were the greatest, but dietary TP elevated (P = 0.004) only 10t-18:1, and total trans-18:1 (excluding 11t-18:1) was 0.47 +/- 0.06 g/100 g of PCD. Dietary SS for finishing steers reduced the incidence of liver abscesses without affecting total lean yield of the carcass, with modest increases in trans fatty acids and in potentially beneficial fatty acids (11t-18:1 and CLA).     

Preen gland function in layer fowls: factors affecting preen oil fatty acid composition

1. Preen oil derived from the preen gland has previously been shown to differ in its composition between birds of different ages, sex and diet. As a part of a larger study on preening behaviour and its components, the relative percentages of fatty acids in preen oil were examined in laying hens that differed in age, beak trimmed status, feather pecking status (pecker and pecked) and method of sampling (either direct from the preen gland or from lipid extracted from feathers). 2. Five experiments are described. Fatty acids extracted from lipid were analysed by gas chromatography (GC). Fatty acid composition was affected by age, by whether or not a bird was feather pecked (but not if it was a feather pecker) and by lipid source. 3. Changes in preen oil composition with age (shown here) may be due to changes in circulating concentrations of hormones. Differences in preen oil composition between feather pecked and non-pecked birds may influence plumage odour and therefore taste, making the plumage of some birds more attractive to pecking than others. 4. The proportions of some fatty acids derived from feathers differed to those extracted from the preen gland. Lipid found on feathers is most likely a combination of that from the preen gland and from sebaceous secretions from the skin.     

The correlationship between the metabolizable energy content,chemical composition and color score in different sources of corn DDGS

Background： This study was conducted to evaluate the apparent metabolizable energy （AME） and true metabolizable energy （TME） contents in 30 sources of corn distillers dried grains with solubles （DDGS） in adult roosters, and establish the prediction equations to estimate the AME and TME value based on its chemical composition and color score. Methods： Twenty-eight sources of corn DDGS made from several processing plants in 11 provinces of China and others imported from the United States. DDGS were analyzed for their metabolizable energy （ME） contents, measured for color score and chemical composition （crude protein, crude fat, ash, neutral detergent fiber, acid detergent fiber）, to predict the equation of ME in DDGS. A precision-fed rooster assay was used, each DDGS sample was tube fed （50 g） to adult roosters. The experiment was conducted as a randomized incomplete block design with 3 periods. Ninety-five adult roosters were used in each period, with 90 being fed the DDGS samples and 5 being fasted to estimate basal endogenous energy losses. Results： Results showed that the AME ranged from 5.93 to 12.19 MJ/kg, TME ranged from 7.28 to 13.54 MJ/kg. Correlations were found between ME and ash content （-0.64, P 〈 0.0]） and between ME and yellowness score （0.39, P 〈 0.05） of the DDGS samples. Furthermore, the best-fit regression equation for AME content of DDGS based on chemical composition and color score was AME = 6.57111 ＋ 0.5]475 GE - 0.10003 NDF ＋ 0.1 3380 ADF ＋ 0.07057 fat - 0.57029 ash - 0.02437 L （R^2 = 0.70）. The best-fit regression equation for TME content of DDGS was TME = 7.92283 ＋ 0.51475 GE - 0.10003 NDF ＋ 0.13380 ADF ＋ 0.07057 fat - 0.57029 ash - 0.02437 L （R2 = 0.70）. Conclusions： This experiment suggested that measuring the chemical composition and color score of a corn DDGS sample may provide a quality parameter for identifying corn DDGS sources energy digestibility and metabolizable energy content.     

Effect of dietary fatty acids on humoral immune response of Turkeys

1. This study examined the effect of increasing amounts of dietary polyunsaturated fatty acids on the fatty acid composition in serum and antibody production following a standard vaccination programme in growing turkeys. Turkey poults were fed on 5 diets containing 75g/kg added fat made up of different proportions of palm and soyabean oils, and were vaccinated against Newcastle disease, infectious bronchitis and necrotic enteritis according to a standard vaccination programme. Blood samples were taken before and one week after each vaccination.

2. Fatty acid composition in serum reflected the composition of the diets although arachidonic acid concentration was not changed by dietary fatty acid content. Growth, erythrocyte and leukocyte parameters were not affected by the respective diets.

3. Specific antibody production was related quadratically to serum linoleic and total n‐6 polyunsaturated fatty acid concentrations. No correlation was found with linolenic or arachidonic acids.

4. It is concluded that dietary fatty acid composition can augment the specific anti‐vaccine immune response in turkey poults.     

Conjugated Linoleic Acid and Dietary Fats Differentially Affect Hepatic ACAT Activity and LDL-Cholesterol in Postweanling Pigs Fed Low-Fat Diets1

ABSTRACT：Two separate studies tested the hypoth- esis that plasma low-density lipoprotein cholesterol LDL-C ） can be decreased by conjugated linoleic acid （CLA） by depressing hepatic acyl-coenzyme A： cholesterol acyltransferase （ACAT） activity. In the first experiment, 3 groups of 6 early-weaned piglets were fed low-fat diets containing either 1.5% CLA, 1.5% corn oil or 1.5% beef tallow;fat provided 8% of the energy intake. In the second experiment, 4 groups of 6 early-weaned piglets were fed high-fat di- ets containing either 15% beef tallow, 12% beef tal- low plus 3% CLA, 15% corn oil, or 12% corn oil plus 3% CLA; fat provided 29% of energy intake. Cholesterol was balanced across diets in both experi-ments. In pigs fed the low-fat diets, all dietary fats in- creased LDL-C and triacylglycerols and decreased high-density lipoprotein cholesterol （ HDL-C ） and very low-density lipoprotein cholesterol （VLDL-C）. LDL-C was the same in pigs fed low-fat tallow or low-fat CLA diets. However, ACAT activity was near- ly 80% higher in pigs fed the low-fat tallow diet than in pigs fed the low-fat CLA diets. All high-fat diets increased LDL-C, HDL-C and triacylglycerols equally with no effect on VLDL-C. There were no unique fat- ty acid effects of the high-fat diets on ACAT activity. We conclude that supplemental fats had differential effects on hepatic ACAT activity and LDL-C, but on- ly in pigs fed low-fat diets.     

Effect of SCD and SREBP genotypes on fatty acid composition in adipose tissue of Japanese Black cattle herds

Fatty acid composition of beef adipose tissue is one of important traits because high proportions of monounsaturated fatty acid are related to favorable beef flavor and tenderness. In this study, we investigated effects of genetic factors such as stearoyl-CoA desaturase (SCD) and sterol regulatory element binding protein (SREBP) on beef carcass traits including fatty acid composition using two cattle populations. Sire effect was significantly related to almost all traits except BMS, suggesting that the trait examined in this study is highly controlled by genetic factors. The effect of SCD genotype on fatty acid composition was detected remarkably in both cattle groups, especially on stearic and oleic acids. This result was consistent with our previous studies and suggests that SCD is associated with fatty acid composition. Unlike SCD genotyping, the effect of SREBP genotype was not identified in this study. Our results suggested that SCD genotype would contribute to improving beef quality in field populations. Further studies about the relationship among these factors will bring an insight into the molecular mechanism of fatty acid metabolism in cattle.     

Conjugated linoleic acid depresses the delta9 desaturase index and stearoyl coenzyme A desaturase enzyme activity in porcine subcutaneous adipose tissue

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.     

Influence of dietary lipid source and strain on fatty acid composition of Muscovy duck meat

A trial was conducted to study the effect of dietary 2% soya bean oil and dietary 2% fish oil (FO) on fatty acid composition of breast meat of two different Muscovy duck (Cairina moschata domestica L.) strains. The two strains were a broiler strain selected for meat production and an unselected rural strain. Fatty acid composition of breast muscle was deeply influenced by lipid source. Dietary FO improved the long chain polyunsaturated fatty acids (LC-PUFAs) of omega 3 series content, while the content of LC-PUFAs of omega 6 series was reduced. Differences in susceptibility in lipid manipulation were found between the two groups of animals suggesting the highest capability of animals belonging to the rural strain in stocking arachidonic acid in breast muscle. As the fatty acid profile of Muscovy duck meat can be considerably modified by changing the fatty acid composition of the diet, and dietary FO represents an easy way to reach this goal, human intake of healthy n-3 LC-PUFAs could be enhanced using this enriched poultry meat, even if the influence of FO on organoleptic characteristics (i.e. off-flavours) must be evaluated.     

Fatty acid composition of muscle and adipose tissue from crossbred bulls and steers

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.