Addition Of Conjugated Linoleic Acid Research Articles

In vitro maturation in synthetic oviductal fluid increases gene expression associated with quality and lipid metabolism in bovine oocytes.

Traditionally, in vitro oocyte and embryo culture progresses through a series of varying culture medium. To investigate simplifying the in vitro production of bovine cumulus-oocyte complexes (COCs), this study used synthetic oviductal fluid (SOF) supplemented with conjugated linoleic acid (CLA). Special interest was placed on gene expression linked to lipid metabolism and oocyte maturation. COCs were matured in different media: Medium 199 (M199 group), M199 with 100 μM CLA (M199 + CLA group), SOF (SOF group), and SOF with 100 μM CLA (SOF + CLA group). COCs matured with SOF showed a higher relative abundance of mRNA of quality indicators gremlin 1 (GREM1) and prostaglandin-endoperoxide synthase 2 (PTGS2) in oocytes, and GREM1 in cumulus cells compared with in the M199 group. SOF medium COCs had a higher relative abundance of fatty acid desaturase 2 (FADS2) compared with the M199 group, which is essential for lipid metabolism in oocytes. Furthermore, the abundance of stearoyl-coenzyme A desaturase 1 (SCD1) in oocytes matured with SOF was not influenced by the addition of CLA, whereas the relative abundance of SCD1 was reduced in M199 medium with CLA. We concluded that maturation in SOF medium results in a greater abundance of genes linked to quality and lipidic metabolism in oocytes, regardless of the addition of CLA.

Effects of dietary conjugated linoleic acid in broiler breeders and egg storage time on the fatty acid profile, lipid oxidation and internal egg quality

Context The need for the storage of fertile eggs is a reality in the poultry industry. At the same time, prolonged storage periods decrease the quality of egg components that are essential for embryo development, and can compromise hatchability and chick quality; thus, the high content of unsaturated fatty acids in embryo tissues increase the susceptibility to peroxidation. Aims The objective of this study was to evaluate the addition of cis-9, trans-11, trans-10 and cis-12 isomers of conjugated linoleic acid (CLA) to the broiler-breeder diet and the storage time on the internal egg quality, composition and lipid oxidation. Methods In total, 22 000 Cobb female broiler breeders of 58 weeks of age were fed with diets containing 0 or 0.024% CLA and fertile eggs were stored 3, 6 or 9 days prior to incubation. In total, 6912 hatching eggs were used in a completely randomised experimental design in a 2 × 3 factorial arrangement (CLA inclusion × egg storage time). At the end of each storage period, 30 eggs per dietary treatment were sampled to analyse yolk and albumen height, percentage and pH, yolk:albumen ratio, yolk diameter and index, Haugh unit (HU), yolk lipid oxidation, acidity and fatty acid profile. Key results The progression of storage negatively affected the internal quality of the eggs; however, inclusion of CLA minimised these effects up to Day 6, especially for yolk diameter, HU, height and albumen pH. The total lipid content was not affected by the dietary treatments; however, CLA inclusion resulted in a higher proportion of stearic acid and a lower concentration of linoleic acid in yolks. Conclusions The changes observed in fatty acid profile of the eggs may have favoured the reduction of lipid oxidation, as shown by the decrease in the acidity index and thiobarbituric acid-reactive substance (TBARS) values at shorter storage periods. Implications The dietary addition of CLA to broiler breeders may be used to preserve the egg internal quality during a short-term storage period.

Influence of CLA addition in non-ruminant diets on lipid index values

In monogastric animals, tissue fatty acid profile directly reflects the fatty acid profile present in the animal’s diet. Inadequate ratio of fatty acids in food can lead to negative effects on human health. Conjugated linoleic acid (CLA) is a group of isomers of linoleic acid (C18:2), and its most interesting role is in the prevention of tumors, atherosclerosis and diabetes. CLA is found in ruminant meat and milk, and since pigs and poultry do not have the ability to synthesize CLA, it is possible to add them to animal feed with biotechnological solutions. The scientific public imposes modern parameters for determining the nutritional value of fatty acids, in which the AI – index of atherogenicity, TI – index of thrombogenicity and H/H - hypocholesterolemic/hypercholesterolemic ratio are distinguished. The aim of this study was to determine the effect CLA addition to the diet of non-ruminants on the lipid indices of certain categories of meat, from the aspect of consumer health needs. A significant influence of the correction of feed’s fatty acid composition on the lipid indices in food of animal origin was determined.

Supplementing conjugated linoleic acid in breeder hens diet increased conjugated linoleic acid incorporation in liver and alters hepatic lipid metabolism in chick offspring.

This experiment was designed to investigate the effect of supplementing conjugated linoleic acid (CLA) in breeder hens diet on development and hepatic lipid metabolism of chick offspring. Hy-Line Brown breeder hens were allocated into two groups, supplemented with 0 (control (CT)) or 0·5 % CLA for 8 weeks. Offspring chicks were grouped according to the mother generation and fed for 7 d. CLA treatment had no significant influence on development, egg quality and fertility of breeder hens but darkened the egg yolks in shade and increased yolk sac mass compared with the CT group. Addition of CLA resulted in increased body mass and liver mass and decreased deposition of subcutaneous adipose tissue in chick offspring. The serum TAG and total cholesterol levels of chick offspring were decreased in CLA group. CLA treatment increased the incorporation of both CLA isomers (c9t11 and t10c12) in the liver of chick offspring, accompanied by the decreased hepatic TAG levels, related to the significant reduction of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) enzyme activities and the increased carnitine palmitoyltransferase-1 (CPT1) enzyme activity. Meanwhile, CLA treatment reduced the mRNA expression of genes related to fatty acid biosynthesis (FAS, ACC and sterol regulatory element-binding protein-1c) and induced the expression of genes related to β-oxidative (CPT1, AMP-activated protein kinase and PPARα) in chick offspring liver. In summary, the addition of CLA in breeder hens diet significantly increased the incorporation of CLA in the liver of chick offspring, which further regulate hepatic lipid metabolism.

Maternal conjugated linoleic acid alters hepatic lipid metabolism via the AMPK signaling pathway in chick embryos

The effects of maternal conjugated linoleic acid (CLA) on embryonic development and hepatic lipid metabolism were investigated in chick embryos. A total of 180 Arbor Acres female broiler breeders (36 wk old) were randomly divided into the following 3 dietary treatment groups: a basic diet (control), a basic diet containing 0.5% CLA (CLA1), and a basic diet containing 1.0% CLA (CLA2). The females were fed for 8 wk, and the eggs from each group were collected and hatched during the last 2 wk. The results showed that the addition of dietary CLA increased the broken egg rate and reduced the fertilization rate and the egg hatchability (P < 0.05). CLA enrichment decreased the polyunsaturated and monounsaturated fatty acids and increased the saturated fatty acids in the yolk sac (P < 0.05). The yolk sac weight, body weight, and body length had a linear decrease with CLA supplementation (P < 0.05). In the developing chick embryo (at E14) and newly hatched chick (D0), the serum triglyceride concentration decreased with maternal CLA supplementation and was accompanied by a reduction in subcutaneous adipose tissue deposition. In addition, maternal CLA supplementation mediated the hepatic lipid metabolism by decreasing the mRNA expression of sterol regulatory element-binding proteins-1c (SREBP-1c), fatty acid synthase and acetyl-CoA carboxylase, and increasing the mRNA expression of adenosine 5′-monophosphate-activated protein kinase α (AMPKα), peroxisome proliferator-activated receptors α (PPARα), liver fatty acid-binding protein, adipose triglyceride lipase and carnitine palmitoyltransferase in embryonic chick livers (P < 0.05). A drop in SREBP-1c protein expression and an increase in the protein expression of p-AMPKα and PPARα were also observed in the liver of chick embryo (P < 0.05). In conclusion, maternal CLA supplementation regulated the fatty acid composition in the yolk sac, and mediated embryonic chick development and hepatic lipometabolism, and these effects may be related to the AMPK pathway. These findings suggest the potential ability of maternal CLA supplementation to reduce fat deposition in chick embryos.

The volatile organic compound profile of ripened cheese is influenced by crude protein shortage and conjugated linoleic acid supplementation in the cow's diet

A shortage in crude protein (CP) and supplementation of conjugated linoleic acids (CLA) in the diets of dairy cows could improve the dairy industry's ecological footprint and the nutritional value of milk, but it is not known what effect such a strategy might have on the aroma profiles of dairy products. The aim of this work was to study the effects of reducing the dietary CP content (from 150 to 123 g/kg of dry matter), with or without a supply of rumen-protected CLA (7.9 g/d C18:2 cis-9,trans-11 and 7.7 g/d C18:2 trans-10,cis-12), on the volatile organic compound (VOC) profile of cheeses ripened for 3 mo. Twenty mid-lactation Holstein-Friesian cows were reared in 4 pens (5 to a pen), and fed 4 different experimental diets over 4 periods of 3 wk each, following a 4 × 4 Latin square design. Twice in each period, 10-L milk samples were taken from each group and used to produce 32 cheeses, which we then analyzed for VOC by solid-phase microextraction and gas chromatography-mass spectrometry. We detected 48 VOC belonging to 10 chemical classes (11 alcohols, 8 ketones, 8 esters, 7 acids, 4 aldehydes, 4 sulfurs, 2 lactones, 2 phenolic, 1 monoterpene, 1 hydrocarbon); these were expressed as concentrations in cheese (quantitative data) or as proportions of total VOC (qualitative data). The results of mixed model analysis showed that the majority of VOC families and individual VOC in ripened cheese were affected by the dietary treatments: CP shortage depressed the concentrations of volatile aldehydes and increased the proportions of some esters and limonene, whereas CLA increased the concentration of total VOC, particularly several acids and esters, and decreased the proportions of ketones and phenolic compounds. The interaction between dietary CP and CLA affected the proportions of alcohols and acids. We performed a factor analysis to extract 5 latent explanatory variables from the individual VOC, which represented 79% of total VOC variance for the quantitative data and 78% for the qualitative data. Addition of CLA decreased the first qualitative factor (the "base aroma" of cheese, explaining 44% of total variance), whereas CP reduction increased the second quantitative factor ("ethyl esters," 15% of total variance) and the third qualitative factor ("butan-," 9% of total variance). In summary, the VOC profile of ripened cheese was heavily influenced by CP content and CLA supplementation in the diets of dairy cows, but the effect on sensorial properties of cheese is also worth considering.

Conjugated linoleic acid regulates lipid metabolism through the expression of selected hepatic genes in laying hens

The effect of dietary conjugated linoleic acid (CLA) supplementation on lipid metabolism in laying hens was investigated. A total of 360 eighteen-wk-old Hy-Line Brown layers were randomly divided into 4 groups that consisted of 6 replicates with 15 birds each. Birds were fed basal diets with 0, 1%, 2%, and 4% CLA addition. The experiment lasted for 56 D after a 7-D adaptation period. Results showed that dietary CLA addition linearly reduced (P < 0.05) abdominal fat percentage but linearly increased (P < 0.05) relative liver weight of layers on day 56. A linear reduction (P < 0.05) in serum low-density lipoprotein cholesterol (LDL-C) level and a linear elevation (P < 0.05) in the ratio of serum high-density lipoprotein cholesterol level to LDL-C level of layers on both days 28 and 56 were observed with dietary CLA addition, which also linearly decreased (P < 0.05) cholesterol content in the liver of layers on day 56 as well as in eggs on both days 28 and 56. Besides, there were linear reductions (P < 0.05) in the gene expression and contents of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and cholesterol 7 alpha hydroxylase 1 (CYP7A1), along with a linear increase (P < 0.05) in the gene expression and content of hepatic low-density lipoprotein receptor (LDLR) in layers responded to dietary CLA addition. In conclusion, dietary CLA supplementation decreased the accumulation of lipids including abdominal fat and cholesterol in the liver and egg of laying hens, probably by upregulating hepatic LDLR expression and downregulating hepatic HMGR and CYP7A1 expression.

Effect of conjugated linoleic acid and different type of dietary fat on serum lipid profile, liver enzymes activity and oxidative stress markers in Wistar rats

Nutritional recommendations emphasize the need to limit consumption of saturated fatty acids and to increase the intake of polyunsaturated fatty acids in the prevention of non-communicable chronic diseases, particularly cardiovascular diseases. Among the fatty acids with health-related effects on the body, conjugated fatty acids are mentioned (i.e. CLA). The current study was designed to determine the effects of conjugated linoleic acid (CLA) on serum lipid profile, glucose, liver enzymes activity (AST and ALT), malonic dialdehyde (MDA) as well as lipid hydroperoxide (LPO) concentrations in rats fed diet differing in type of dietary fat. Male Wistar rats were divided into six groups and fed the following diets: control AIN-93G diet contained soybean oil (O) and diets with modification of fat source: butter (B) and margarine (M). The experimental diets were supplemented with 1% of conjugated linoleic acid (O+CLA, B+CLA, M+CLA). After 21 days the blood was collected and lipid profile, glucose, liver enzymes, MDA as well as LPO were analyzed. The dietary treatments had no significant effect on the body weight and liver weight of the animals. The concentrations of total cholesterol (TC) and LDL+VLDL cholesterol were unchanged. Both experimental factors (fat source and CLA) had a significant influence on the TAG and HDL levels. Margarine (M) significantly increased the TAG concentration, whereas CLA had a significant impact on the TAG reduction (M+CLA). Glucose level was significantly decreased in all groups fed diets supplemented with CLA. Serum ALT significantly increased in all CLA groups. Fat source had statistically significant influence on the MDA concentration. The LPO level was significantly elevated in all CLA groups. There was statistically significant interaction of experimental factors (fat source and CLA supplementation) on LPO level. Margarine had an adverse effect on the rat’s lipid profile. However, in the group fed with margarine, the addition of CLA decreased the concentration of TAG. Regardless of the type of the dietary fat, CLA supplementation increased the level of LPO in the blood serum of animals.

Conjugated linoleic acid supplementation does not improve boar semen quality and does not change its fatty acid profile

The aim of this study was to evaluate the effects of adding conjugated linoleic acid (CLA) to boar diets on semen producion and characteristics, the fatty acid profile of spermatozoa, and on testicle and boar carcass parameters. Ten lean-type terminal-line (Yorkshire x Landrace x Petrain) adult boars were randomly assigned to one of two treatments: (1) a control diet and (2) the same diet with 1% CLA. The research was conducted in Mexico, and the animals were exposed to ambient temperatures betwen 13.5 and 26.3 °C. Boars were ejaculated twice per week a 12-week period to examine semen production and characteristics. The results suggest that supplementation of boar diets with CLA did not affect the spermatozoa fatty acid profile, semen volume, sperm concetration, viability, or motility, nor did it cause abnormal sperm morphology. Compared to controls, boar fed a CLA diet had a higher seminal pH and increased backfat thickness. In summary, this study indicates that CLA addition in boar diet does not change the semen characteristics of fatty acid profile of spermatozoa; however, it increases backfat thickness in sexually mature boars.

Strategies for Producing and Incorporating Conjugated Linoleic Acid-Rich Oils in Foods.

Conjugated linoleic acid (CLA) is in ruminant-derived foods and is known to combat obesity-related diseases. However, CLA levels in a healthy diet are too low to produce a clinical effect. Therefore, CLA has been produced by linoleic isomerization through fermentation and chemical catalysis. Many of these techniques are not practical for food production, but a recent development has enabled production of CLA-rich triglyceride vegetable oils from high linoleic acid oils by a minor modification of conventional food-oil processing techniques. These oils were used to produce common lipid-based food, such as margarine, shortenings, and salad dressings, whose quality was enhanced by the presence of CLA-rich oil and provided a significant CLA source. Meat and egg CLA content and subsequent food quality can also be increased by addition of dietary CLA. However, consumer awareness of CLA benefits needs to increase prior to commercial-scale production of CLA-rich oil.

The influence of dietary nitrogen reduction and conjugated linoleic acid supply to dairy cows on fatty acids in milk and their transfer to ripened cheese.

The aim of this study was to investigate the consequences of reducing the dietary crude protein content, with or without a supply of protected conjugated linoleic acid (CLA), on the milk fatty acid (FA) yield and recovery in 90d ripened cheese. Twenty mid-lactation Friesian dairy cows were reared for 4 periods of 3wk each in groups of 5, following a 4×4 Latin square design. Cows were fed 4 different rations, consisting of a combination of the 2 dietary crude protein levels [150 (CP15) or 123 (CP12) g of crude protein/kg of dry matter], with or without a conjugated linoleic acid supply (80g/d, providing 5.57 and 5.40g/d of C18:2 cis-9,trans-11 and C18:2 trans-10,cis-12, respectively). Milk yield was recorded. Twice in each period, milk samples were analyzed for protein, fat, and lactose content, and 10 L milk samples (pooled by group) were processed to produce 96 cheeses, which were ripened for 90d. Milk and cheese fat were analyzed for their FA profiles. Milk and cheese FA were expressed as daily yields and relative proportions, and nutrient recoveries were computed. Dietary crude protein reduction had small or no effects on the yield and relative presence of FA in milk and cheese, except for a small increase in mid-chain branched saturated fatty acids. The CLA supply strongly reduced the yield of various categories of FA, and had major effects on short-chain FA of de novo synthesis, leading to changes in the relative proportions of the various FA in milk and cheese. The addition of CLA tended to reduce uniformly the recovery of all milk constituents and of short-, medium-, and long-chain FA groups, but we observed large differences among individual FA with apparent recoveries ranging between 640 and 1,710g/kg. The highest recoveries were found for polyunsaturated long-chain FA, the lowest for saturated or monounsaturated short- or medium-chain FA. A notable rearrangement of these FA components, particularly the minor ones, took place during ripening.

Cechy tuszy oraz jakosc miesa swin Sywionych pasza z dodatkiem sprzeSonego kwasu linolowego lub oleju slonecznikowego

The aim of the study was to compare meat and fat content and meat quality of pigs fed diet supplemented with sunflower oil (SFO) or conjugated linoleic acid (CLA) and animals not receiving the supplement SFO or CLA (control group). The experiment consisted of 116 pigs, divided into three groups: two experimental (n = 40) where animals were fed feed supplemented with 2% sunflower oil (SFO) or conjugated linoleic acid (CLA) and control (n = 36). Fattening pigs were kept and fed in standardized conditions. The animals were slaughtered at a body weight of 120 kg. Meat quality traits (pH, drip loss, backfat fat content, colour, MLLT muscle dry matter content, fat in the dry matter, IMF in MLLT) were determined. Summarizing obtained results it should be concluded that 2% sunflower oil or conjugated linoleic acid did not affect the meat quality. The experimental animals were characterized by high meat content (58.26% - SFO addition; 57.63% - CLA addition; 57.99% C group) and low fat content (from 14.35 mm in SFO group up to 14.70 mm in CLA group).

Effects of whole linseed and rumen-protected conjugated linoleic acid enriched diets on beef quality

Instrumental assessments and sensory tests were performed to evaluate the effects of diet and postmortem ageing time (1, 7 and 21 days) on beef quality. A total of 48 Friesian calves were randomly allocated to four dietary treatments: control, whole linseed (10% linseed), conjugated linoleic acid (CLA) (2% protected CLA), and whole linseed+CLA (10% linseed and 2% protected CLA). Animals were slaughtered at 458±16.6 kg live weight and 11 months of age. Ageing was more significant than diet on most instrumental parameters. Meat from linseed enriched diets had greater drip loss (P⩽0.001) and intramuscular fat (P⩽0.01) than meat from animals fed CLA. Beef aged for 7 and 21 days had lower cooking losses (P⩽0.01) and shear force (P⩽0.001) than beef aged for 1 day. Lightness was affected only by display time. The addition of CLA in the diet increased hue and yellowness, whereas the inclusion of linseed decreased these values, as well as increased redness. Linseed in the diet decreased fat odour (P⩽0.05), but increased beef (P⩽0.01) and liver (P⩽0.05) flavours. Meat aged for 21 days was significantly more rancid (P⩽0.001), even under vacuum storage. Several organoleptic properties were improved with the inclusion of linseed in the diet, whereas they remained unaffected by the inclusion of CLA.

Responses in colostrum production and immunoglobulin concentrations to conjugated linoleic acid fed to multiparous sows during late gestation

This study was conducted to determine whether supplemental conjugated linoleic acid (CLA) fed during late gestation affects reproductive performance, colostrum production and colostral immunoglobulin (Ig) levels of multiparous sows. Forty-eight, pregnant, Landrace×Large White, multiparous sows were allotted to four dietary treatments (n=12), control (CTR, no CLA addition) and 7.5, 15.0, or 22.5g/kg CLA supplementation from d 85 of gestation until farrowing. The CLA was added at the expense of soybean oil. All sows were fed the same commercial lactation diet postpartum. Blood samples were collected from sows on d 85, 100 and 112 of gestation while blood samples were obtained from neonatal piglets 24h postpartum. Colostrum was collected immediately after farrowing and its production was estimated for 24h starting with the birth of the first piglet. Neither the body weight nor backfat thickness of sows were altered by dietary CLA. Reproductive performance, piglet growth and calculated colostrum production were also unaffected. Compared with the CTR diet, dietary CLA supplementation during late gestation decreased (P<0.01) the colostral fat, and increased (P<0.01) the concentrations of IgG, IgA, and IgM in colostrum (P<0.01). The concentrations of serum Ig and interleukin-2 on d 112 of gestation were increased (P<0.01) in sows receiving CLA, although those factors did not differ among different levels of CLA supplementation. Serum IgG, IgA, and IgM concentrations in piglets from sows fed diets containing CLA were increased (P<0.05) 24h postpartum. This study indicates that dietary CLA has potential immunomodulatory effects in gestating sows and neonatal piglets, whereas there were no differences within the CLA treatments.

Conjugated linoleic acid isomers strongly improve the redox status of bovine mammary epithelial cells (BME-UV1)

Some studies have shown the protective effects of conjugated linoleic acid (CLA) isomers against oxidative stress and lipid peroxidation in animal models, but no information is available about CLA and changes in oxidative status of the bovine mammary gland. The objectives of the study were to assess in vitro the effect of CLA on the cellular antioxidant response of bovine mammary cells, to examine whether CLA isomers could play a role in cell protection against the oxidative stress, and to study the molecular mechanism involved. For the study, BME-UV1 cells, a bovine mammary epithelial cell line, were used as the experimental model. The BME-UV1 cells were treated with complete medium containing 50 µM cis-9,trans-11 CLA (c9,t11 CLA), trans-10,cis-12 CLA (t10,c12 CLA), and CLA mixture (1:1, cis-9,trans-11: trans-10,cis-12 CLA). To monitor cellular uptake of CLA isomers, cells and culture medium were collected at 0, 3, and 48h from CLA addition for lipid extraction and fatty acid analyses. To assess the cellular antioxidant response, glutathione (GSH/GSSH), NADPH, and γ-glutamyl-cysteine ligase activity was measured after 48h from addition of CLA. Cytoplasmic superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and glutathione reductase activities and mRNA were also determined. Intracellular reactive oxygen species and thiobarbituric acid reactive substance production were assessed in cells supplemented with CLA isomers. Cell viability after 3h to H2O2 exposure was assessed to evaluate and to compare the potential protection of different CLA isomers against H2O2-induced oxidative stress. Mammary cells readily picked up all CLA isomers, their accumulation was time dependent, and main metabolites at 48h are two 18:3 isomers. The CLA treatment induced an intracellular GSH increase, matched by high concentration of NADPH, and an increase of γ-glutamyl-cysteine ligase activity mainly in cells treated with the t10,c12 CLA isomer. The CLA isomer treatment of bovine mammary cells increased superoxide dismutase, glutathione peroxidase, and glutathione S-transferase activity and decreased glutathione reductase activity, but no changes in gene expression of these antioxidant enzymes were observed. Cells supplemented with CLA isomers showed a reduction in intracellular reactive oxygen species and thiobarbituric acid reactive substance levels. All CLA isomers were able to enhance cell resistance against H2O2-induced oxidative stress. These suggest an antioxidant role of CLA, in particular of t10,c12 CLA, by developing a significantly high redox status in cells.

Fatty acid composition of young Holstein bulls fed whole linseed and rumen-protected conjugated linoleic acid enriched diets

Forty-eight young Holstein bulls were used to evaluate the effect of whole linseed and conjugated linoleic acid (CLA) supplementation on beef fatty acid profile in intramuscular and subcutaneous fat. Animals were fed one of four isoenergetic and isoproteic diets: control (0% linseed, 0% CLA), linseed (10% linseed, 0% CLA), CLA (0% linseed, 2% CLA), and linseed plus CLA (10% linseed, 2% CLA). The fatty acid profile had similar trends in intramuscular and subcutaneous fat when diets were enriched with linseed and/or CLA, increasing the level of CLAc9,t11 and α-linolenic acid (ALA), and decreasing the n-6/n-3 fatty acid ratio. Supplementation with linseed improved the fatty acid profile by increasing the proportions of n-3 and CLA fatty acids and decreasing the n-6/n-3 ratio compared with the control. CLA addition achieved similar CLA tissue levels to linseed supplementation, but similar n-3 proportions to the control. Linseed plus CLA supplementation was more effective in increasing total polyunsaturated fatty acids and CLA compared with their individual addition. It is concluded that supplementation of whole linseed and/or CLA in bulls resulted in an increase in beef fat of some fatty acids considered to be of potential benefit to human health.

The Effect of Direct Addition of Conjugated Linoleic Acid on the Formation of Heterocyclic Aromatic Amines in Beef Chops

The effect of direct addition of conjugated linoleic acid (CLA) (0.05, 0.1, 0.25 and 0.5%) to beef chops on the formation of heterocyclic aromatic amines (HCAs) was investigated. Chops were cooked at three different temperatures (150, 200, 250C). CLA addition had no significant effect (P > 0.05) on water content, pH, thiobarbituric acid reactive substance, L*, a* and b* values and cooking loss of the samples, while cooking temperatures had a significant effect (P < 0.01) on these parameters except for pH value. While 4,8-DiMeIQx and MeAαC could not be detected, varying amounts of IQx (up to 0.53 ng/g), IQ (up to 0.18 ng/g), MeIQx (up to 0.09 ng/g), MeIQ (up to 0.56 ng/g), 7,8-DiMeIQx (up to 0.19 ng/g), PhIP (up to 2.61 ng/g) and AαC (up to 0.58 ng/g) were detected. Total HCA content ranged between 0.10 and 4.49 ng/g. Up to 0.1% CLA reduced the total HCA amount at all cooking temperatures. Practical Applications Conjugated linoleic acid (CLA) is a bioactive compound that is found naturally in foods from ruminant. There is limited information about the direct addition of CLA to meat in the literature. In addition, to the best of our knowledge, there are no reports on the effect of CLA on some quality properties of beef chop and the formation of heterocyclic aromatic amines. Therefore, in the present study, we aim to explore the effects of CLA usage on these parameters.

Synthetic methods to obtain conjugated linoleic acids (CLAs) by catalysis – A review

The addition of synthetic CLA is a possible way in order to compose foods enriched with conjugated linoleic acids (CLAs). The most environmental friendly methods for CLA synthesis are based on microbial biosynthesis. With homogeneous catalysis using organometallic catalysts (Ru and Rh complexes) high (approximately 80%) yields were obtained with high selectivity related to bioactive isomers. The heterogeneous catalysis has the advantage that at the end of the reaction there is no need for a supplementary separation operation or recycling of the catalyst. In heterogeneous process, the maximum yield may even be higher than 90% and the selectivity remains quite high as the reaction conditions are optimized. The substrates for obtaining CLAs are, in general, linoleic acid or alkyl linoleates and the catalysis is acidic. The yield and the selectivity depend on the strength and the type of acidic sites, as well as on the size distribution of the particles. Beside the existing catalytic methods, a photocatalytic process with UV and visible light irradiation with iodine promoter can be applied.

Effect of CLA supplementation to low-protein diets on the growth performance, carcass characteristics, plasma urea nitrogen concentration, and fatty acid profile in the meat of pigs

To analyze the effect of conjugated linoleic acid (CLA) on the meat of pigs (0,1%) and three crude protein (CP) levels (nursery: 20.5, 16.0, 14.5%; growing: 16, 14.5, 11.5%; and finishing: 14.0, 12.5, 11% CP), studies were conducted with 36 hybrid (Yorkshire×Landrace×Duroc) barrows (17.3-83.5 kg), which were individually penned and allotted in a completely randomized design in a factorial (2×3) arrangement for 84 d. The analysis by phases indicated that CP level affected some variables. Average daily gain, average daily feed intake, fat free lean gain, backfat thickness, longissimus muscle area and final body weight were reduced (P≤0.05) feeding the lowest CP diet in nursery and growing pigs. Plasma urea nitrogen concentration was also lower (P≤0.05) in the growing and finishing phases when fed the lowest CP level. The global analysis showed that all the analyzed variables (except feed gain ratio, lean meat percentage and plasma urea nitrogen concentration) were reduced (P≤0.05) in the pigs fed low-protein diets; plasma urea nitrogen concentration tended to be lower (P=0.07) when CP was reduced. The fatty acid profile of the meat (semimembranosus and longissimus muscles) indicated that CLA addition increased CLA isomers and total saturated fatty acids, and reduced the total monounsaturated fatty acids (P≤0.05). α-Linolenic acid was lowered in longissimus muscle of pigs fed LPD (P=0.08). These results indicated that reducing the crude protein concentration in the diet of fattening pigs from 20.5 to 16.0% in nursery phase; from 16.0 to 14.5% in growing stage; and from 14.0 to 12.5% in finishing pigs, did not negatively affect the growth performance, nor carcass characteristics. The results also showed that the addition of CLA did not improve pig response and the concentration of unsaturated fatty acids and total lipids altered the feeding LPD.

Dietary Conjugated Linoleic Acid (CLA) increases milk yield without losing body weight in lactating sows.

This study was conducted to evaluate the effects of dietary conjugated linoleic acid (CLA) on the performance of lactating sows and piglets as well as the immunity of piglets suckling from sows fed CLA. Eighteen multiparous Duroc sows with an average body weight (BW) of 232.0 ± 6.38 kg were randomly selected and assigned to two dietary treatments (n = 9 for each treatment), control (no CLA addition) and 1% CLA supplementation. For the control diet, CLA was replaced with soybean oil. Experimental diets were fed to sows during a 28-day lactation period. Litter size for each sow was standardized to nine piglets by cross-fostering within 24 hours after birth. Sow milk and blood samples were taken from sows and piglets after 21 and 27 days of lactation, respectively. Loss of BW was significantly (p < 0.05) higher in sows fed control diet compared to sows fed CLA diet. Piglet weights at weaning and weight gain during suckling were significantly (p < 0.05) higher in sows fed CLA compared to sows fed control diet. Serum non-esterified fatty acid (NEFA) and urea nitrogen concentrations were significantly (p < 0.05) lower in sows fed CLA than in sows fed soybean oil. IgG concentrations of the groups supplemented with CLA increased by 49% in sow serum (p < 0.0001), 23% in milk (p < 0.05), and 35% in piglet serum (p < 0.05) compared with the control group. Sows fed CLA showed an increase of 10% in milk yield compared with sows fed soybean oil (p < 0.05), even though there was no difference in daily feed intake between the treatments. Milk fat content was significantly (p < 0.05) lower in sows fed CLA than in sows fed soybean oil. Solid-not-fat yield was significantly (p < 0.05) higher in sows supplemented with CLA than in sows fed control diet and also protein-to-fat ratio in milk was significantly (p < 0.05) higher in sows fed CLA compared with the control group. The results show that CLA supplementation to sows increased milk yield without losing BW during lactation, whereas soybean oil supplementation resulted in severe BW loss.