Total CLA Research Articles

Feeding wheat dried distillers grains with solubles improves beef trans and conjugated linoleic acid profiles1

In western Canada, ethanol is produced mainly from wheat. As the demand for wheat increases, so do grain prices, which in turn creates incentives for feeding reduced-cost distillers coproducts to livestock. Substitution of wheat dried distillers grains plus solubles (DDGS) for barley grain may also create opportunities for enhancing beef fatty acid profiles because reducing starch concomitantly increases dietary fiber and oil and may shift PUFA biohydrogenation toward a healthier trans and CLA profile. To study this potential, heifers were fed diets containing 0, 20, 40, or 60% wheat DDGS (DM basis) substituted for rolled barley (n = 24; 133-d finishing period). Adding DDGS increased dietary oil (from 1.9 to 3.7%), but dietary fatty acid compositions remained consistent. Feeding increasing amounts of DDGS linearly decreased total diaphragm fatty acids on a milligram per gram basis (P = 0.031). For both brisket fat and diaphragm, feeding increasing amounts of DDGS caused linear increases in percentages of 18:2n-6 (P = 0.001) and total n-6 fatty acids (P = 0.001) but did not change the concentrations of individual or total n-3 fatty acids. Feeding increasing amounts of DDGS did not change the content of total trans MUFA in either brisket fat or diaphragm but led to linear decreases in 10t-18:1 (P = 0.033, brisket fat; P = 0.004, diaphragm) and increases in 11t-18:1 (P = 0.005, brisket fat; P = 0.003, diaphragm). Feeding increasing amounts of DDGS also caused a linear increase in 9c11t-18:2 (P = 0.044, brisket fat; P = 0.023, diaphragm) and total CLA (P = 0.086, brisket fat; P = 0.039, diaphragm). Overall, feeding DDGS enhanced the fatty acid composition of beef by decreasing 10t-18:1 while increasing the major CLA isomer (9c,11t-18:2) and its precursor 11t-18:1.

Double-muscling character influences the trans-18:1 and conjugated linoleic acid profiles in concentrate-fed yearling bulls

Seventy-five yearling bulls of the "Asturiana de los Valles" northern-Spanish beef breed (double-muscled, mh/mh, n=24; heterozygous, mh/+, n=26; normal, +/+, n=25) were produced under intensive conditions and the effects of double-muscling genotype on trans-18:1 and CLA isomer profiles were examined. Total trans-18:1 contents, measured as percentages of total fatty acid methyl esters, were 10.98-15.07% in backfat and 8.64-9.46% in muscle, and the major isomer was 10t-18:1 in all animals. In mh/+ animals, 11t-18:1 was the second most abundant trans isomer in muscle whereas in mh/mh and +/+ animals 11t-18:1 and 13t/14t-18:1 were relatively similar. Total CLA percentages were 0.71-0.85% in backfat and 0.32-0.40% in muscle. The highest total CLA percentage found was in mh/+, intermediate in +/+ and lowest in mh/mh animals (P<0.05). Heterozygous animals had significantly higher percentages of 9c,11t- (P<0.01), 11t,13c- (P<0.01) and 9c,11c-18:2 (P<0.05) and also significantly higher percentages of the sum of 9c,11t-/11t,13c-/11t,13t-18:2. Overall, mh/+ animals produced meat with a slightly better trans and CLA profile (i.e., less 10t-18:1 and more 11t-18:1 and 9c,11t-18:2) than other genotypes, however, further improvements would still be necessary to achieve a profile with a positive health image.

Effects of dietary polyunsaturated fatty acid supplementation on fatty acid composition in muscle and subcutaneous adipose tissue of lambs1

Lambs (n = 48) were used in a 2 x 2 factorial arrangement of treatments to evaluate effects of inclusion of oil containing PUFA in high-concentrate diets (with or without) and duration of oil supplementation (pre- vs. postweaning) on CLA concentration of muscle and adipose tissue. Lambs were fed preweaning creep diets (with or without oil) corresponding to the dietary lactation treatment diet (with or without oil) of the dam. Dams blocked by lambing date and rearing type were randomly assigned to 1 of 2 lactation dietary treatments with or without oil supplementation. Creep diets contained approximately 70% concentrate and 30% roughage and were provided to lambs for ad libitum intake. At weaning (58.7 +/- 2.5 d of age), lambs (n = 48) were randomly assigned within preweaning treatment groups to 1 of 2 postweaning dietary treatments (with or without oil) and 16 pens in a randomized block design, blocked by sex and BW. Postweaning diets were formulated to contain approximately 80% concentrate and 20% roughage and were fed once daily for ad libitum intake. Soybean and linseed oil (2:1, respectively) replaced ground corn and provided 3% additional fat in pre- and postweaning diets. Lambs were slaughtered at 60.3 +/- 4.2 kg of BW. A subcutaneous fat (SQ) sample was obtained within 1 h postmortem and a LM sample at the 12th rib was obtained 24 h postmortem, and both were analyzed for fatty acid profile. Feedlot performance and carcass measurements were not affected (P >or= 0.26) by oil supplementation. Total CLA content of LM and SQ was not affected (P >or= 0.08) by oil supplementation pre- or postweaning, but trans-10, cis-12 CLA was greater (P = 0.02) in SQ from lambs supplemented with oil postweaning. Total PUFA content in LM was greater (P = 0.02) in lambs supplemented with oil pre- or postweaning as a result of increased concentrations of 18:2cis-9, cis-12 and longer chain PUFA. Conversely, pre- and postweaning oil supplementation resulted in less (P = 0.04) MUFA content in LM. Only postweaning oil supplementation increased (P = 0.001) SQ PUFA content. Feeding oils containing PUFA to lambs pre- and postweaning did not increase CLA content of muscle, whereas postweaning oil supplementation minimally increased CLA concentration of SQ fat. Inclusion of soybean and linseed oil in pre- and postweaning diets increased total PUFA content of SQ fat and muscle tissue without adversely affecting growth performance or carcass characteristics.

Δ 9 desaturase protein expression and fatty acid composition of longissimus dorsi muscle in lambs fed green herbage or concentrate with or without added tannins

The aims of this study were to investigate the effect of feeding system and of supplementation of tannins (8.93% DM) on the relationship between intramuscular fat content, fatty acid composition and Δ 9desaturase (Δ 9d) protein expression in longissimus dorsi muscle of lamb. Twenty-eight Comisana lambs (age 45 days) were fed either vetch ( Vicia sativa) or concentrate. The herbage diet was (i) lower in saturated fatty acids (especially in C16:0), C18:1 n−9 and in C18:2 n−6; (ii) higher in C16:1 and C18:3 n−3 when compared to concentrate. Within each feeding system the lambs were divided into two sub-groups, one of which received the diet without tannins supplementation, and the other was fed the diets supplemented with the tannins from Quebracho ( Schinopsis lorentzii). The animals were slaughtered at age 105 days. The concentrate feeding system increased ( p < 0.01) the total intramuscular fat content and the amount of SFA, MUFA and n−6 PUFA and decreased the level of n−3 PUFA ( p = 0.05) when compared to the vetch-fed animals but did not affect Δ 9 desaturase protein expression. There was no correlation between Δ 9d protein expression and total intramuscular fatty acids, CLA and MUFA level. It was suggested that in ruminants, in contrast to monogastric animals, Δ 9d expression does not play the key role in intramuscular fatty acids formation. Tannins supplementation resulted in higher ( p < 0.05) muscle levels of transC18:1 and C18:2 n−6. It has also increased Δ 9d expression in the case of herbage-based diet but not in the case of concentrate-based diet. The mechanism of tannins action on the enzyme expression needs to be elucidated.

Selective production ofcis-9,trans-11 isomer of conjugated linoleic acid fromtrans-vaccenic acid methyl ester byDelacroixia coronata

Bio-process development for isomer selective and efficient production of cis-9,trans-11-octadecadienoic acid (CLA) from trans-vaccenic acid (t-VA, trans-11-octadecenoic acid) through microbial fatty acid Delta9-desaturation reaction. A total of 550 strains of fungi and yeasts were screened for CLA production from t-VA through Delta9 desaturation. Delacroixia coronata IFO 8586 was selected as a potent producer of CLA from t-VA. Efficient CLA production was observed during cultivation in medium supplemented with the methyl ester of t-VA (t-VAME). Under the optimal conditions with 33.3 mg ml(-1) of t-VAME as substrate, 10.5 mg ml(-1) CLA was produced by D. coronata IFO 8586 after 7 days of cultivation in the medium containing dextrin (5.0%), tryptone (2.0%) and thiourea (0.83 micromol ml(-1)). The strain produced the cis-9,trans-11 isomer of CLA selectively (98% of total CLA), with a small amount of the trans-9,trans-11 isomer (2% of total CLA), mainly in the form of triacylglycerols (69% of total CLA). A practical bio-process for selective production of cis-9,trans-11 isomer of CLA using filamentous fungus D. coronata IFO 8586 was successfully established. Isomer selective bio-process for the practical production of cis-9,trans-11-CLA was first established. The process is benefitable for expanding the application of CLA for medicinal and nutraceutical purposes.

Subcutaneous fat composition of youthful and mature Canadian beef: emphasis on individual conjugated linoleic acid and trans-18:1 isomers

A comprehensive evaluation of the fatty acid composition of subcutaneous adipose tissue from beef cattle produced in western Canada was undertaken to determine if the current Canadian grading system is able to distinguish classes of animals with value added potential due to their fatty acid composition. Grades included youthful Canadian Yield Grade 1 A/AA beef, under (YUTM) and over (YOTM) 30 mo of age and the four mature grades (D1, D2, D2 and D4). Subcutaneous fat between the 12th and 13th ribs over the longissimus muscle was obtained from 18–21 animals per grade. Fatty acids were analyzed using a combination of silver-ion HPLC and GC with a highly polar 100 m column. There were no differences in total trans-18:1 content amongst grades, but adipose tissue from grade D1, D2 and D4 had more 11t-18:1 than YUTM (P &lt; 0.05), whereas adipose tissue from YUTM carcasses had more 10t-18:1 than all other grades (P &lt; 0.05). Adipose tissue from YUTM carcasses also had less total CLA (P &lt; 0.05) than the D grades, mainly due to a lower level of 9c,11t-CLA, but they had slightly more 7t,9c-CLA and 10t,12c-CLA (P &lt; 0.05). Adipose tissue from YOTM and D grades contained more n-3 fatty acids relative to YUTM (0.56% vs. 0.29%; P &lt; 0.05) and lower n-6:n-3 ratios (P &lt; 0.05). Overall, older animals (YOTM and D grades) had adipose tissue compositions with higher levels of fatty acids with reported health benefits. Taken together, these higher levels may provide opportunities for value added marketing if regulatory authorities allow claims for their enrichment based on demonstrated health benefits. Higher concentrations of beneficial fatty acids, however, need to be considered within the context of the complete fatty acid profile and it would be important to demonstrate their advantages in the presence of relatively high levels of saturated fatty acids. Key words: CLA, trans, vaccenic acid, rumenic acid, beef, adipose tissue

Fatty acid composition of intramuscular fat from Nellore steers fed dry or high moisture corn and calcium salts of fatty acids

The purpose of this work was to evaluate the fatty acid composition of the Longissimus muscle from carcasses of Nellore steers fed diets with calcium salts of fatty acids (CSFA) and high moisture corn. Forty eight steers were fed during 70 days four diets containing dry corn (DC), high moisture corn (HM), dry corn plus CSFA (DC-CSFA) or high moisture corn plus CSFA (HM-CSFA). Fatty acid composition of the Longissimus muscle was determined by gas chromatography. Corn type had no effect on the ether extract percentage and in the content of the majority of the fatty acids, although steers fed HMC showed higher levels of polyunsaturated fatty acids and polyunsaturated/saturated ratio. Feeding CSFA increased ether extract percentage but had no effect on total of saturated, unsaturated and saturated: unsaturated ratio. Both high moisture corn and calcium salts of fatty acids increased CLA (cis9, trans11) and total CLA concentrations in intramuscular fat.

Carcass Characteristics, Chemical Composition and Fatty Acid Profile of the Longissimus Muscle of Bulls (Bos taurus indicus vs. Bos taurus taurus) Finished in Pasture Systems

This experiment was carried out to evaluate the carcass characteristics, chemical composition and fatty acid profile of the Longissimus muscle (LM) of three cattle genetic groups (Puruna, PUR, 11; 1/2 Puruna vs. 1/2 British, PUB, 6 and 1/2 Charolais vs. 1/2 Caracu, CHC, 10) finished in pasture systems. The field work took place at the Lapa Research Farm of the Agronomic Institute of Parana, in the city of Lapa, south Brazil. The animals were fed during the winter with corn silage, cottonseed meal, cracked corn, urea, limestone and mineral salts as sources of protein, as well as an energy supplement, in pasture systems of Brachiaria decumbens Stapf. The animal groups were slaughtered at 20 months of age, at 501±22.6 kg live weight. CHC bulls had higher (p 0.10) between PUR and PUB. Hot carcass dressing percentage was higher (p 0.05) between PUR and CHC bulls. Fat thickness was similar (p>0.10) among all genetic groups. However, the Longissimus area of CHC bulls was greater (p 0.10) the marbling of Longissimus. There was no observed difference (p>0.10) in moisture, ash, crude protein and total cholesterol contents among the three genetic groups. On the other hand, the total lipid percentage was higher (p<0.05) for the PUB genetic group in comparison with PUR and CHC. CLA percentage was highest for PUR animals. However, total CLA amounts were not altered by the different genetic groups.

Nonionophore antibiotics do not affect the trans-18:1 and conjugated linoleic acid composition in beef adipose tissue1

The common practice in North American feedlot industries is to add antibiotics to the diet to prevent disease and improve both BW gain and feed efficiency. In this study, 240 crossbred steer calves were backgrounded on a 54% silage diet for 80 d and fed a finishing diet consisting of 81% barley grain, 10% barley silage, and 7.5% supplement (DM basis) with and without in-feed antibiotics for approximately 120 d. Calves were assigned to 1 of 5 treatments: a control with no antibiotics, 11 mg/kg of chlortetracycline, 44 mg/kg of chlortetracycline, 44 mg/kg of chlortetracycline plus 44 mg/kg of sulfamethazine, and 11 mg/ kg of tylosin phosphate. A combination of GLC and silver-ion HPLC methods was used to analyze the fatty acid composition of brisket adipose tissue, with emphasis on trans-18:1 and CLA isomers. The inclusion of nonionophore antibiotics in the diet had little effect on the fatty acid composition, except that feeding either 44 mg/kg of chlortetracycline or 11 mg/kg of tylosin caused small increases in 9c-14:1 and 16:0 relative to the control (0.26 and 0.9 g/100 g of total fatty acids, respectively). Likewise, profiles of trans-18:1 and CLA isomers were unchanged by antibiotics, but across treatments the predominant trans-18:1 isomer was 10t-18:1 (where t = trans; 3.22%) at 3 times the concentration of the second most abundant isomer (11t-18:1; vaccenic acid, 1.05%). Rumenic acid (9c,11t-18:2, where c = cis) was the major CLA isomer at 61% of total CLA, followed by 7t,9c-18:2 at 9%. Because no other effects on fatty acid composition were evident, data for trans-18:1 and CLA were pooled across treatments to investigate possible relationships among rumen PUFA metabolites. The total trans-18:1 content in brisket adipose tissue was positively correlated with 10t-18:1, but not with 11t-18:1, whereas the total CLA was positively correlated with 9c,11t-18:2, but not with 7t,9c-18:2. The 7t,9c-18:2 was, however, positively correlated with 10t-18:1 and 6t/7t/8t-18:1 but was negatively correlated with rumenic acid. These metabolic interrelationships suggest the presence of bacterial populations with distinct pathways for PUFA biohydrogenation in which either 10t-18:1 or 11t-18:1 predominate. Overall, the nonionophore antibiotics tested did not appreciably change adipose tissue composition and consequently could not be used to improve the trans-18:1 or CLA profile (i.e., increase vaccenic and rumenic acids at the expense of 10t-18:1).

Effect of incremental levels of sunflower-seed oil in the diet on ruminal lipid metabolism in lactating cows

Based on the potential benefits of cis-9, trans-11-conjugated linoleic acid (CLA) for human health there is interest in developing sustainable nutritional strategies for enhancing the concentration of this fatty acid in ruminant-derived foods. Most evidence to date suggests that endogenous synthesis is the major source of cis-9, trans-11 in milk fat and ruminal outflow is limited and largely independent of dietary 18 : 2n-6 supply. Four lactating cows fitted with a rumen cannula were used in a 4 x 4 Latin square with 14 d experimental periods to examine the effects of sunflower-seed oil (SFO) as a source of 18 : 2n-6 on ruminal lipid metabolism. Cows were offered grass silage-based diets supplemented with 0, 250, 500 or 750 g SFO/d. Supplements of SFO had no effect on DM intake, milk fat or protein secretion, but increased linearly (P < 0.01) milk yield and milk lactose output and shifted (P < 0.001) rumen fermentation towards propionate at the expense of acetate. SFO supplements increased linearly (P < 0.05) the flow of 18 : 0, 18 : 1, 18 : 2n-6 and total CLA at the omasum and enhanced ruminal cis-9-18 : 1, 18 : 2n-6 and 18 : 3n-3 metabolism. Flows of all-trans- (Delta4-16) and cis- (Delta9-16) 18 : 1 isomers were elevated, while increases in ruminal CLA outflow were confined to trans-8, trans-10 and geometric 9,11 and 10,12 isomers. It is concluded that supplementing grass silage-based diets with plant oils rich in 18 : 2n-6 enhances ruminal outflow of trans-11-18 : 1 and cis-9, trans-11-CLA in lactating cows.

Supplemental algal meal alters the ruminal trans-18:1 fatty acid and conjugated linoleic acid composition in cattle1

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.

Estimation of factors influencing fatty acid profiles in light lambs

Fatty acid composition of intramuscular, intermuscular, subcutaneous, omental and kidney knob fat depots of eighty male light lambs (±21 kg live weight) from five Spanish sheep breeds was analysed. Fat depot, anatomical depot location (internal, external and intramuscular), breed (Spanish Merino, Grazalema Merino, Churra Lebrijana, Segureña and Montesina), weaning type (weaning at 45 days after birth or no weaning) and subcutaneous fat thickness factors were analyzed using a statistical model to quantify their contribution to the variation of each fatty acid. Production system was the main factor to explain variations in overall fatty acid profiles (34.68%). However, for several fatty acids and indices (arachidonic, linoleic, PUFA, n − 3/ n − 6) anatomical depot location was the most significant factor. Feeding system explained 65.49% of CLA variance, indicating a strong influence of suckling period length on CLA deposition in lambs’ fat. Moreover, due to the lack of interaction between anatomical depot location or depot and breed type or weaning system for total CLA, for future research only one depot would be enough to study the effect of those factors on CLA levels.

Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on lipid content and palatability in beef cattle1

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.

Effect of breed and nutrition on milk quality of sheep

Sheep breeding has a relevant economic and environmental role in the Alps, where cheese production is often obtained from local breeds. Recent studies have emphasized the role of fatty acid composition and CLA content of fat because of its considerable contribution to the final nutritional characteristics of cheese and to the quality of fat intake in the diet of consumers. Aim of the study was to evaluate the breed and nutrition effects on fatty acid composition and CLA content of milk fat during lactation of four Alpine sheep breeds (Frabosana, Delle Langhe, Savoiarda and Lacaune). At beginning of lactation, animals were stabled and fed hay and concentrate (pea and corn meal). From 60 to 90 days in milk, all the ewes of the four breeds grazed on the same valley pastures, and from middle to late lactation on the same alpine pastures. Feed samples of hay, concentrate and pasture grass were analysed for chemical composition and fatty acid composition. Milk samples were collected from 4 animals of each breed at different stage of lactation, and analysed for fatty acid composition of fat and CLA. Data were analysed with the “Statistica” package for Principal Components Analysis (PCA). Results showed that two main principal components (PC) explained more than 50% of cumulative variance. The first PC was positively correlated to SFA amount and negatively correlated to MUFA and PUFA of milk fat; the second PC was negatively correlated to the total CLA of milk fat. The analysis scattered the 4 different breeds during the stabled phase (beginning of lactation), showing that the breed has an influence on fatty acid composition of milk fat and CLA when animal are fed the same diet. From 60 days in milk to end of lactation, when sheep grazed on valley or alpine pastures, the differences in fatty acid composition and CLA were influenced only by the diet. Further studies are needed to better understand the interaction between nutrition and lactation stage on characteristics of fatty acid composition and CLA content.

Soybean Oil 및 Flaxseed Oil 첨가 배양시 탄수화물 첨가수준에 의한 반추미생물의 Bio-hydrogenation과 CLA 생성에 미치는 효과

본 실험은 대두유 또는 아마유를 in vitro 방법으로 배양 할 때, 탄수화물원의 첨가수준이 반추위 박테리아에 의한 bio-hydrogenation과 CLA 생성에 미치는 효과를 조사하였다. 4수준(0%, 0.3%, 0.6% 그리고 0.9%, w/v)의 혼합된 탄수화물원(glucose, cellobiose, soluble starch, 1:1:1, w/w/w)과 두 종류의 oil을 cellulose powder에 흡착시킨 형태로 각각 60mg씩 인공타액(120ml)과 반추위액(30ml)이 혼합된 배양액(150ml)에 넣은 다음 39℃에서 12시간동안 혐기적으로 배양하였다. 배양액의 pH와 암모니아 농도는 두 종류 oil을 첨가한 배양액 모두에서 탄수화물원의 첨가 수준이 높을수록 pH와 암모니아 농도가 낮았다(P<0.05). 탄수화물원의 첨가 수준이 증가할수록 total VFA 생성량 역시 증가되었으나(P<0.01) 첨가한 oil 간의 차이는 없었다. 배양시간이 경과됨에 따라 탄수화물원의 첨가수준이 높을수록 propionate의 조성비율이 증가된 반면(P<0.001) acetate와 butyrate의 조성비율은 감소되었다. 배양 후 3시간이 경과하였을 때 배양액 내 oleic acid의 조성비율은 대두유에 비하여 아마유를 첨가한 배양액에서 낮았으나(P<0.001) linoleic acid의 비율은 높았다(P<0.001). 이와는 달리 탄수화물원의 수준이 증가될수록 stearic acid(P<0.05), CLA(P<0.01) 및 cis-9, trans-11 CLA(P<0.001)의 조성비율은 감소되었으나, linoleic acid의 조성 비율은 증가되었다(P<0.05). Linolenic acid의 조성비율에 있어서는 첨가된 oil의 종류와 첨가된 탄수화물원의 수준간의 상호작용이 있는 것으로 나타났는데(P<0.001), 12시간의 배양종료 후 대두유 첨가구에 비해 아마유 첨가구에서 stearic acid(P<0.01), oleic acid(P<0.001), 그리고 trans-11C18:1(P<0.01)의 조성비율이 감소된 반면, linoleic acid(P<0.001)와 linolenic acid(P<0.01)의 조성비율은 증가되었다. 탄수화물원의 첨가수준이 증가될수록 stearic acid와 총 CLA의 조성비는 감소되었으나(P<0.01), trans-11-C18:1(P<0.05)와 linoleic acid(P<0.01)의 조성비율은 증가되었다. 배양 12시간 후 배양액 내의 oleic acid (P<0.05), linoleic acid(P<0.05) 및 linolenic acid(P<0.01)의 조성비율에 있어서는 첨가한 oil의 종류와 첨가한 탄수화물원의 수준간의 상호작용이 있었는데, 탄수화물원의 첨가수준이 감소됨에 따라 cis-9, trans-11 CLA와 trans-10, cis-12 CLA의 조성비 역시 감소되는 경향이었으나 첨가한 oil의 종류에 대한 영향은 거의 받지 않았다. 본 실험의 결과를 종합해 볼 때, 탄수화물의 첨가수준과 oil의 첨가는 반추미생물의 bio-hydrogenation 작용 및 CLA 생성에 영향할 수 있는 것으로 여겨진다. An in vitro study was conducted to examine the effect of addition level of carbohydrates on fermentation characteristics, and bio-hydrogenation of unsaturated fatty acids by mixed rumen bacteria when incubated with soybean oil or flaxseed oil. Four levels(0%, 0.3%, 0.6% and 0.9%, w/v) of the mixed carbohydrates(glucose, cellobiose, soluble starch, 1:1:1, in weight basis) and oil sources(soybean or flaxseed oil, 60mg in 150ml culture solution) were added to the mixed solution of strained rumen fluid with artificial saliva(1:4, v/v), and incubated anaerobically for 12 hours at 39℃. pH and ammonia-N concentration were lower by increasing the substrate levels at all incubation periods(P<0.05～P<0.001). The propionate proportion increased(P<0.001), but acetic acid and butyric acid decreased(P<0.001) with the substrate level at 6 and 12 h incubations. Oil sources did not influence the proportions of individual VFA. At the end of incubation, the proportions of C18:0(P<0.01), C18:1(P<0.001) and trans-11C-18:1(P<0.01) were reduced but those of C18:2(P<0.001) and C18:3(P<0.01) were enhanced by the addition of flaxseed oil compared to addition of soybean oil. The proportions of C18:0 and total CLA were reduced(P<0.01) but those of trans-11-C18: (P<0.05) and C18:2(P<0.01) were increased with the substrate level when incubated with soybean oil or flaxseed oil. There were interactions(P<0.05) in the proportions of C18:1, C18:2 and C18:3(P<0.01) between oil source and substrate level. The proportions of cis-9, trans-11-CLA and trans-10, cis-12-CLA tended to reduce with substrate level, although there was no significant difference between treatments.

Conjugated linoleic acid content of beef differs by feeding regime and muscle

The project objective was to determine the CLA content of three muscles ( Longissimus lumborum, LD; Semimembranosus, SM; Triceps brachii, TB), in both raw and cooked states, in cattle finished on pasture or with grain supplements. Cattle were randomly assigned to one of four finishing regimens; pasture ( n = 11), pasture with grain supplement ( n = 11), pasture with grain supplement containing soyoil ( n = 12), and feedlot ( n = 12). In the raw state, TB had higher ( P < 0.05) CLA than LD or SM on a mg/g sample basis. Total CLA was higher ( P < 0.05) in the soyoil diet when compared to the other three feeding regimes on a mg/g sample basis and when expressed as mg/g fat in both raw and cooked analyses. Pasture inclusion produced higher levels ( P < 0.05) of total CLA than the feedlot diet on a mg/g fat basis for cooked samples while maintaining acceptable eating quality.

Effects of forage source and supplementation with soybean and marine algal oil on milk fatty acid composition of ewes

The objective of the present studies was to determine effects of basal dietary forage source on the response of milk fatty acid composition to an oil supplement based (2:1, respectively, w/w) on soybean oil and marine algae biomass oil high in cis-9, cis-12 C18:2 n − 3 and C22:6 n − 3, respectively. In Study 1, Hampshire × Dorset ewes (48) were randomly assigned to one of four treatments and 12 pens in a completely randomized design blocked on the basis of lambing date and number of lambs suckled. Control rations (60:40 forage:concentrate, dry matter (DM) basis) based on alfalfa pellets (AP) or corn silage (CS) were fed from lambing. Beginning at 22 days postpartum, three pens of ewes fed AP and three pens of ewes fed CS were supplemented with oil (30 g/kg of ration DM) in place of corn meal. Average ewe DM intake (DMI) and average daily gain (ADG) were measured weekly. Milk yield and composition were measured at 42 days postpartum. DMI was lower (P<0.02) for CS and for oil, but milk yield was not affected by forage source or oil supplementation. Milk fat content was higher for oil (P<0.10) and milk protein content was higher for AP (P<0.04). Total CLA concentration (g/100 g fatty acids) increased (P<0.01) with CS and oil, and the response to oil was greater for AP (P<0.04). Similarly, total trans-C18:1 and C22:6 ω−3 concentrations were higher for CS and oil, but the response to oil was greater for CS (P<0.06 and P<0.01, respectively). In Study 2, the experiment was repeated using alfalfa haylage (AH) instead of AP. The DMI decreased (P<0.05) with oil feeding, but was not affected by forage source. Milk yield was decreased by feeding oil with AH, but not by feeding oil with CS (P<0.03). Milk fat content tended to be increased by feeding oil with AH, but tended to be decreased by feeding oil with CS (P<0.08). Total CLA concentration was increased (P<0.01) for AH versus CS and by oil, and the response to oil supplementation was greater for AH (P<0.01). In contrast, total trans-C18:1 concentration was higher for CS versus AH, with a greater response to oil for CS (P<0.05). Feeding marine oil increased the C22:6 ω−3 (P<0.01) concentration, and the response was greater for AH (P<0.04). To further characterize the response of milk fat composition to dietary oil in ewes, a third study used six pens of three ewes each assigned to either the control CS diet used for Study 2 or the same diet supplemented with 45 g/kg (DM basis) of the oil mixture. Feeding oil had no effect on DMI, milk yield or milk fat concentration, but again increased (P<0.001) total trans-C18:1 and C22:6 ω−3 concentrations and numerically increased (114%) total CLA concentration. Milk fatty acid composition responses to supplemental vegetable and marine oils were affected by forage source. Milk trans-C18:1 concentration was higher when CS was fed in Studies 1 and 2, but the effect of forage species on CLA concentration differed between studies, which may reflect differences in diet PUFA content and consumption, as well as amounts of dietary starch and fiber consumed. Despite large increases in trans-C18:1 concentration, milk fat content was not decreased by feeding unsaturated oils to ewes, even at diet levels of 45 g/kg of ration DM.

Enhancement of the conjugated linoleic acid content of buffalo milk and milk products through green fodder feeding

An attempt was made to increase CLA content in milk of buffaloes by feeding them on Berseem ( Trifolium alexandrinum) fodder. Eighteen Murrah buffaloes, having similar milk yield and stage of lactation were divided into three groups. All the groups were offered ad lib. wheat straw during the 60-day experimental period. Their nutritional requirements were fulfilled through a concentrate mixture (Group I), concentrate mixture + Berseem (Group II) and Berseem (Group III). The ratio of Berseem, wheat straw and concentrate in the diet was 0:42:58, 50:25:25 and 87:13:0 on dry matter basis in the three groups, respectively. Milk yield was recorded daily and its chemical composition was determined fortnightly. Milk products such as ghee, paneer and mozzarella cheese were prepared using the milk of each group at fortnightly intervals. There was no effect of dietary treatments on milk yield and its composition. Average total CLA content (mg/g fat) was 7.7, 13.4, 17.0 in milk; 9.1, 13.4, 18.3 in paneer; 8.2, 12.7, 18.8 in ghee and 8.0, 12.0 and 16.3 in cheese in Groups I–III, respectively, showing increase in CLA in milk and milk products (P<0.1) due to Berseem feeding. The major fraction of CLA was cis9, trans11 CLA (C18:2), which was highest in Group III followed by Groups II and I. Omega 3 fatty acids content in milk fat was 4.5, 9.9 and 14.2 mg/g in Groups I–III, whereas the value for Omega 6 in respective groups was 16.4, 16.0 and 16.0 mg/g. Similar trends were observed in the corresponding milk products. The values of Omega 3 were higher (0.1) in Group III but there was no change in Omega 6 content due to the dietary treatments. The ratio of omega-3 and omega-6 fatty acids in milk and milk products was 1:1 in Group III, fed mainly on Berseem fodder.

Effects of margarine and butter consumption on distribution of trans‐18∶1 fatty acid isomers and conjugated linoleic acid in major serum lipid classes in lactating women

Trans FA (TFA) have at least one trans double bond and comprise several isomers and types, including many of the CLA (e.g., c9,t11-18:2 CLA). Some TFA may have adverse effects (e.g., cardiovascular disease), whereas some are thought to have beneficial effects (e.g., anticarcinogenicity). The presence of TFA in human tissues and fluids is related to dietary intake, although this relationship is not completely understood--especially in regard to serum lipid fractions. This study was conducted as part of an investigation designed to test the influence of butter (B), "low TFA" margarine (LT), and regular margarine (RM) on milk fat content. Here we tested the secondary hypothesis that consumption of B, LT, and RM by lactating women would result in differential distribution of TFA and CLA in major serum lipid classes. Breast-feeding women (n = 11) participated in this randomized Latin-square study consisting of five periods: intervention I (5 d), washout I (7 d), intervention II (5 d), washout II (7 d), and intervention III (5 d). Extracted serum lipid was separated into cholesterol ester (CE), TAG, and phospholipid (PL) fractions and analyzed for total and isomeric TFA and CLA concentrations. Data indicate that TAG consistently contained the highest concentration of total t-18:1. No interaction between treatment and fraction was found for any of the t-18:1 isomers identified. Absolute concentration of each t-18:1 isomer was greatest during the RM period, regardless of fraction. On a relative basis, concentrations of t10-18:1 and t12-18:1 were most responsive to treatment in the CE fraction. The concentration of c9,t11-18:2 CLA was highest in the TAG fraction and lowest in the PL fraction, regardless of treatment. In summary, these results indicate (i) that there is a differential distribution of some isomeric TFA and CLA among human serum lipid fractions and (ii) that dietary TFA intake influences absolute and relative concentrations of some of the isomers in selected fractions.

Relationship between fat globule size and chemical and fatty acid composition of cow’s milk in mid lactation

The milk of 57 Italian Friesian cows in mid lactation was analysed in order to define the relationship between some qualitative milk parameters and the size of milk fat globules. The study focused on the morphometric evaluation of milk fat globules, chemical parameters and fatty acid composition of the milk. The results show that a prevalence of milk fat globules with a diameter < 6 |im is positively correlated (P< 0.01) with the percentage of dry matter and lipids, whereas the greater presence of globules with a diameter > 6nm was associated (P< 0.01) with greater milk yield and a higher percentage of lactose, non-fat dry matter and ash. Regarding fatty acid composition, milk samples with a higher percentage of globules smaller than 6 nm in diameter contain more unsaturated fatty acids (P< 0.01), in particular C18:l, C18:2 and total CLA, while higher percentages of the larger fat globules indicated a prevalence of saturated fatty acids (P< 0.01). Based on these results, a diameter of 6 urn in fat globules may be considered a "threshold value" for the definition of various qualitative traits of cow's milk.<