Dietary Conjugated Linoleic Acid Research Articles

Conjugated linoleic acid from Suaeda salsa improves the intestinal health in T2DM mice by regulating colonic barrier function, intestinal glycolipid transporters and intestinal flora

Metabolic diseases such as obesity and diabetes are increasing rapidly, leading to adverse effects on patients’ intestinal function and health. In this study, high-purity conjugated linoleic acid (CLA) was extracted using glycerol from Suaeda salsa, followed by purification using simulated moving bed chromatography technique. Subsequently, type 2 diabetic mellitus (T2DM) mice were administered c9,t11-CLA (100 mg/kg), t10,c12-CLA (100 mg/kg), or varying doses of high-purity CLA diet (100, 600, or 1800 mg/kg) for a duration of five weeks. The impact on intestinal function was evaluated through morphological and tissue function studies combined with 16S rDNA sequencing technology and other techniques. The results demonstrated that the CLA was purified to 97.81% and significantly reduced blood glucose and lipid levels in T2DM mice by inhibiting the expression of small intestinal glucose and lipid transporters; enhanced colon barrier function by upregulating the expression of colon tight junction proteins; activated Jnk-c-Jun pathway to suppress intestinal cell apoptosis thereby improving survival rate; improved intestinal microecological health by modulating intestinal flora composition and metabolic function. These findings demonstrate the potential advantageous impact and mechanism of CLA derived from S. salsa in enhancing intestinal health among individuals with T2DM, providing a substantial theoretical and practical foundation for investigating the hypoglycemic effects of CLA and addressing global public health concerns.

Conjugated linoleic acid regulates adipocyte fatty acid binding protein expression via peroxisome proliferator-activated receptor α signaling pathway and increases intramuscular fat content.

Intramuscular fat (IMF) is correlated positively with meat tenderness, juiciness and taste that affected sensory meat quality. Conjugated linoleic acid (CLA) has been extensively researched to increase IMF content in animals, however, the regulatory mechanism remains unclear. Adipocyte fatty acid binding protein (A-FABP) gene has been proposed as candidates for IMF accretion. The purpose of this study is to explore the molecular regulatory pathways of CLA on intramuscular fat deposition. Here, our results by cell lines indicated that CLA treatment promoted the expression of A-FABP through activated the transcription factor of peroxisome proliferator-activated receptor α (PPARα). Moreover, in an animal model, we discovered that dietary supplemental with CLA significantly enhanced IMF deposition by up-regulating the mRNA and protein expression of PPARα and A-FABP in the muscle tissues of mice. In addition, our current study also demonstrated that dietary CLA increased mRNA expression of genes and enzymes involved in fatty acid synthesis and lipid metabolism the muscle tissues of mice. These findings suggest that CLA mainly increases the expression of A-FABP through PPARα signaling pathway and regulates the expression of genes and enzymes related to IMF deposition, thus increasing IMF content. These results contribute to better understanding the molecular mechanism of IMF accretion in animals for the improvement of meat quality.

The effect of conjugated linoleic acids on the growth performance, carcase composition and meat quality of fattening rabbits

This experiment was conducted to study the effects of dietary conjugated linoleic acids (CLAs) on the growth performance, fat metabolism, carcase composition and muscle quality of fattening rabbits. A total of 160 Minxinan black rabbits aged 75 days with body weights of 1658.9 ± 188.8 g were randomly divided into 4 groups. They were fed a basic diet supplemented with 0 (control), 0.5%, 1.0%, or 1.5% CLA for 50 days. Dietary CLA reduced the feed intake and serum triglyceride and cholesterol levels. In addition, the crude protein content in rabbit meat was increased, along with the cholesterol and the ether extract levels in the 1.5% depression group. Moreover, the fatty acid composition in rabbit meat was changed, and the content of polyunsaturated fatty acids/monounsaturated fatty acids (PUFAs/MUFAs) increased with the increasing levels of CLA addition. These findings indicate that CLA greatly improved the nutritional value of rabbit meat. From an economic point of view, CLA would normally be included at a concentration of 0.5% in the formulation of feeds for fattening rabbits. HIGHLIGHTS Minxinan black rabbits were fed conjugated linoleic acid (CLA)- supplemented diets for 50 d. CLA decreased the feed intake of experimental rabbits. CLA has significant effects on fat deposition and serum triglyceride and cholesterol levels. CLA greatly improved the nutritional value of rabbit meat. The recommended CLA level is 0.5% for meat rabbits．

Dietary Conjugated Linoleic Acid Modulates the Hepatic Circadian Clock Program via PPARα/REV-ERBα-Mediated Chromatin Modification in Mice.

Scope: Disruptions of circadian rhythm cause metabolic disorders and are closely related to dietary factors. In this study, we investigated the interplays between the dietary conjugated linoleic acid (CLA)-induced hepatic steatosis and the circadian clock regulation, in association with lipid homeostasis.Methods and Results: Exposure of mice to 1.5% dietary CLA for 28 days caused insulin resistance, enlarged livers, caused hepatic steatosis, and increased triglyceride levels. Transcriptional profiling showed that hepatic circadian clock genes were significantly downregulated with increased expression of the negative transcription factor, REV-ERBα. We uncovered that the nuclear receptor (NR) PPARα, as a major target of dietary CLA, drives REV-ERBα expression via its binding to key genes of the circadian clock, including Cry1 and Clock, and the recruitment of histone marks and cofactors. The PPARα or REV-ERBα inhibition blocked the physical connection of this NR pair, reduced the cobinding of PPARα and REV-ERBα to the genomic DNA response element, and abolished histone modifications in the CLA-hepatocytes. In addition, we demonstrated that CLA promotes PPARα driving REV-ERBα transcriptional activity by directly binding to the PPAR response element (PPRE) at the Nr1d1 gene.Conclusions: Our results add a layer to the understanding of the peripheral clock feedback loop, which involves the PPARα-REV-ERBα, and provide guidance for nutrients optimization in circadian physiology.

EFFECT OF CONJUGATED LINOLEIC ACID FEEDING PERIODS ON FATTY ACID PROFILE AND NUTRITIONAL QUALITY OF <i>Astyanax altiparanae</i>

The effects of feeding diets with conjugated linoleic acid (CLA) to Astyanax altiparanae for different periods were investigated on carcasses’ fatty acid profile and nutritional quality. The trial was laid out in a complete randomized design with eight feeding periods (0, 7, 14, 21, 28, 35, 42, and 49 days) and four replicates. A total of 240 fish (3.4 ± 0.3 g) were distributed into four aquariums and fed with the diet containing 32% crude protein, 15 MJ kg-1 gross energy, and 2.5% of CLA. Feeding CLA diet for 49 days resulted in the higher deposition of CLA, CLA isomers, and docosahexaenoic acid (DHA). The isomer c9,t11 was highly deposited than the t10,c12. Polyunsaturated fatty acids (PUFA), n-3, and n-6 increased with feeding period, whereas saturated (SFA), monounsaturated, and medium-chain fatty acids decreased. PUFA/SFA ratio, DHA/EPA, EPA+DHA, and thrombogenicity index increased linearly. Whereas atherogenicity index reduced, hypocholesterolemic/hypercholesterolemic ratio increased in quadratic effects over feeding time. No difference was observed for the n-6/n-3 ratio. Feeding A. altiparanae with 2.5% of CLA for a minimum of 35 days improves the fatty acid profile and provides a commercial product with good nutritional quality and functional benefits.

Dietary cis-9, trans-11-conjugated linoleic acid reduces amyloid \u03b2-protein accumulation and upregulates anti-inflammatory cytokines in an Alzheimer\u2019s disease mouse model

Conjugated linoleic acid (CLA) is an isomer of linoleic acid (LA). The predominant dietary CLA is cis-9, trans-11-CLA (c-9, t-11-CLA), which constitutes up to ~ 90% of total CLA and is thought to be responsible for the positive health benefits associated with CLA. However, the effects of c-9, t-11-CLA on Alzheimer’s disease (AD) remain to be elucidated. In this study, we investigated the effect of dietary intake of c-9, t-11-CLA on the pathogenesis of an AD mouse model. We found that c-9, t-11-CLA diet-fed AD model mice significantly exhibited (1) a decrease in amyloid-β protein (Aβ) levels in the hippocampus, (2) an increase in the number of microglia, and (3) an increase in the number of astrocytes expressing the anti-inflammatory cytokines, interleukin-10 and 19 (IL-10, IL-19), with no change in the total number of astrocytes. In addition, liquid chromatography–tandem mass spectrometry (LC–MS/MS) and gas chromatographic analysis revealed that the levels of lysophosphatidylcholine (LPC) containing c-9, t-11-CLA (CLA-LPC) and free c-9, t-11-CLA were significantly increased in the brain of c-9, t-11-CLA diet-fed mice. Thus, dietary c-9, t-11-CLA entered the brain and appeared to exhibit beneficial effects on AD, including a decrease in Aβ levels and suppression of inflammation.

Dietary conjugated linoleic acid supplementation alleviates high lipid-induced intestinal damage in grass carp (Ctenopharyngodon idella)

High lipid diet has been shown to increase the intestinal permeability and inflammatory properties in mammals, and the conjugated linoleic acid (CLA) could alleviate the symptoms caused by high lipid diet. However, the information about the impact of high lipid diet on the intestine of fish was limited, and the effect of CLA on intestinal changes induced by high lipid diet in fish is still unknown. Therefore, an 8-week feeding trial was conducted to investigate CLA’s potential effects against high lipid diet-induced intestinal physical and immune barrier damage in grass carp (Ctenopharyngodon idella). Three isonitrogenous diets, including fish meal-control diet, control diet supplemented with 3.5% soybean oil as high lipid diet (HL), and HL replaced with a 2.5% CLA diet (CLA) formulated. Compared to the control group, HL significantly increased the expression of pro-inflammation genes (TNF-α, IL-8, IL-1β, NF-κB p65, IκBα, IKKα, IKKβ, and IKKγ) and down-regulated the gene expression of anti-inflammation cytokine (IL-10). The expression of intestinal tight junction proteins (ZO-1, occludin, claudin c, and claudin b) in fish fed with high lipid diets was lower than those fed with control diets. In the CLA group, the gene expression of pro-inflammation cytokines was decreased, and the expression level of the anti-inflammation cytokine was increased, compared with those in HL group. Moreover, feeding with high lipid diets induced fish intestine and dietary CLA damage could alleviate the symptom as shown by HE staining. In conclusion, this research revealed that CLA could mitigate high lipid diet-induced inflammation and permeability in the intestine of grass carp.

Effects of Dietary Supplementation of Conjugated Linoleic Acids and Their Inclusion in Semen Extenders on Bovine Sperm Quality.

Simple SummarySuboptimal fertility in males accounts for about two-thirds of infertility cases, thus being of serious concern for the dairy industry, where optimal fertility is fundamental for farm profitability. Although genetic defects responsible for subfertility have been identified, the role of seminal compounds on fertility remain unclear. Feeding rumen-protected isomers of conjugated linoleic acid (CLA) to dairy cows reportedly enhances circulating insulin-like growth factor I (IGF-I) levels. In breeding bulls, the IGF-I concentration in seminal plasma has been positively correlated with fertility rates. Therefore, the objective of the study was to evaluate the effect of dietary CLA supplementation and of their inclusion to the semen extender on bovine semen quality and freezability.Isomers of conjugated linoleic acid (CLA) enhances circulating insulin-like growth factor I (IGF-I) levels. Furthermore, fertility rate of breeding bulls is positively correlated to seminal plasma IGF-I concentration. Our objective was to evaluate the effect of dietary CLA supplementation and inclusion to the semen extender on bovine semen quality and freezability. Fourteen bulls, randomly assigned to control (CTL) and CLA (50 g/day) groups, were supplemented for 10 weeks. Samples were collected at Weeks −2 (before supplementation), 0, 4, 6 (during supplementation), 10, and 11 (after supplementation). Blood and seminal plasma were analyzed for IGF-I; the ejaculates were frozen in the following subgroups: CTL (no addition to semen extender), CLA c9, t11 (50 µM), CLA c9, t11 (100 µM), CLA t10, c12 (50 µM), CLA t10, c12 (100 µM), and CLA mix (50 µM each of CLA c9, t11 and CLA t10, c12). Sperm motility, morphology, viability, mitochondrial membrane potential, and reactive oxidative species were assessed. CLA supplementation decreased ejaculates’ total volume, increased sperm concentration, beat cross frequency, and decreased oxidative stress; it also increased plasma and seminal plasma IGF-I levels compared to the CTL. The inclusion of CLA c9, t11 100 µM and CLA mixture in the extender increased live spermatozoa percentage post-thawing compared to other groups. Our results show a beneficial effect of CLA supplementation on semen quality; however, further studies evaluating fertilization rates are necessary to corroborate the results.

Conjugated Linoleic Acid and Brain Metabolism: A Possible Anti-Neuroinflammatory Role Mediated by PPARα Activation.

Fatty acids play a crucial role in the brain as specific receptor ligands and as precursors of bioactive metabolites. Conjugated linoleic acid (CLA), a group of positional and geometric isomers of linoleic acid (LA, 18:2 n-6) present in meat and dairy products of ruminants and synthesized endogenously in non-ruminants and humans, has been shown to possess different nutritional properties associated with health benefits. Its ability to bind to peroxisome proliferator-activated receptor (PPAR) α, a nuclear receptor key regulator of fatty acid metabolism and inflammatory responses, partly mediates these beneficial effects. CLA is incorporated and metabolized into brain tissue where induces the biosynthesis of endogenous PPARα ligands palmitoylethanolamide (PEA) and oleoylethanolamide (OEA), likely through a positive feedback mechanism where PPARα activation sustains its own cellular effects through ligand biosynthesis. In addition to PPARα, PEA and OEA may as well bind to other receptors such as TRPV1, further extending CLA own anti-neuroinflammatory actions. Future studies are needed to investigate whether dietary CLA may exert anti-inflammatory activity, particularly in the setting of neurodegenerative diseases and neuropsychiatric disorders with a neuroinflammatory basis.

Effects of dietary conjugated linoleic acid on metabolic status, BW and expression of genes related to lipid metabolism in adipose tissue of dairy cows during peripartum

Conjugated linoleic acid (CLA) dietary supplementation reduces milk fat content and yield, but its effects on lipid metabolism and energy status remain controversial. The objective of this study was to investigate the effects of dietary CLA on adipose tissue (AT) mRNA abundance of genes related to lipid metabolism, plasma indicators of metabolic status, body condition score (BCS) and BW changes in dairy cows. Sixteen multiparous Holstein cows (3.2 ± 1.4 lactations, 615 ± 15 kg BW) were randomly assigned to treatments: 1) CLA; rumen-protected CLA (75 g/d) or 2) Control; equivalent amount of rumen inert fatty acid (FA) as the previous diet (78 g/d), from −20.2 ± 3.2 (mean ± SEM) to 21d relative to calving (d 0). Subcutaneous AT was biopsied from the tail-head region at d 21 to determine the mRNA abundance of genes related to lipid metabolism. Blood samples were collected at −20.2 ± 3.2, 0, 7, 14 and 21d relative to calving to determine plasma non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), insulin and glucose. Conjugated linoleic acid decreased milk fat yield and milk fat content by 15 and 16%, respectively. Cows fed CLA had lower plasma NEFA and BHBA and greater glucose and insulin concentrations (P < 0.05). Mean BCS at 21d postpartum was greater (P < 0.01; 2.89 vs 2.25), and BCS loss from the day of enrollment to 21d postpartum was reduced (P < 0.01; −0.13 vs −0.64) in the CLA group. The expression of acylcoenzyme A oxidase, carnitine palmitoyltransferase 1A, hormone-sensitive lipase, β2 adrenergic receptor and acetyl-CoA carboxylase was downregulated by CLA supplementation, whereas the expression of sterol regulatory element binding protein, lipoprotein lipase and peroxisome proliferator-activated receptor gamma was upregulated (P < 0.01). In summary, CLA-supplemented cows showed signs of better metabolic status and less severe fat mobilization. Moreover, CLA increased mRNA abundance of genes related to lipogenesis and decreased mRNA abundance of genes related to FA oxidation and lipolysis in the AT of dairy cows during early lactation.

The effects of diets containing two corn stubble levels and three non-hydrogenated lipids sources on fattening performance, carcase, and meat quality of male hair-lambs

Research regarding the association of fatty acids (FA) with corn stubble in feedlot lambs is limited. FA dietary supplements can reduce the digestibility of neutral detergent fibre (NDF). However, it is not known if the NDF amount added with corn stubble and FA source in the diet can influence the content of polyunsaturated fatty acids (PUFA) and the conjugated linoleic acid (CLA), all of which are related to meat quality. In this study, 96 male-lambs (29 ± 4.9 kg) were assigned in two dietary NDF levels [25% (NDF-25) and 29% (NDF-29)] and four supplemental fat treatments [no supplemental (C), 3% CLA-60, 3% Safflower oil (SAF) and 3% linseed oil (LIN)] evaluated in a 2 × 4 factorial arrangement of treatments. Compared with CLA diets, diets supplemented with SAF and LIN contained more C18:2. Dietary forage level did not affect average daily gain, feed efficiency, or carcase characteristics (p = .56). With NDF-29 increased meat protein content (2%, p < .05). Meat chromatic b* values were greater (p = .02) with NDF-25. Control vs. supplemental lipids (SL) MUFA and PUFA increased in the muscle with SL. The endogenous level of CLA in muscle improved (p < .05) in the muscle with SL. Juiciness meat increased with both NDF levels and lipid supplements (p = .06). In conclusion, protein content and juiciness in the meat improve with NDF-29 (as corn stubble) on a diet. Similarly, SAF and LIN increase the content of PUFA and CLA in meat. Highlights A slight increase of NDF from 25% to 29% added with corn stubble within an iso-energetic diet, change the colour and some sensory variables of the lamb meat. Safflower and linseed oils included in the diet at 3% improve the content of conjugated linoleic acid in lamb meat. The General Quality index in the meat sensory analysis is not affected by inclusion levels of fibre (NDF 25 vs. 29) and lipids (3%) in the diet of hair lambs.

Evaluation of feeding periods of dietary conjugated linoleic acid supplementation on growth performance, nutrient digestibility, blood profiles, and meat quality in finishing pigs

This study was conducted to evaluate feeding periods of dietary conjugated linoleic acid (CLA) supplementation on growth performance, nutrient digestibility, blood profiles, and meat quality in finishing pigs. A total of 150 finishing pigs [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 83.13 ± 1.91 kg were randomly allocated into one of three treatments (10 pens per treatment, five pigs per pen) based on their BW. Dietary treatments consisted of supplementing the basal diet with 1.0% CLA during 2, 3, and 4 wk prior to finishing. Pigs fed CLA diets 2 wk before finishing had a higher overall average daily gain (ADG) and gain-to-feed ratio (G/F) than those fed CLA diets 4 wk before finishing (P &lt; 0.05). In the whole experiment, pigs fed CLA diets 2 wk before finishing had a higher serum low-density lipoprotein (LDL) than those fed CLA diets 3 and 4 wk before finishing. However, pigs that received CLA diets 4 wk before finishing had higher triglyceride levels (P &lt; 0.05). Feeding 1% CLA diets 4 wk before finishing improved meat color and firmness. Taken together, feeding 1% CLA diet 4 wk before finishing increased ADG, G/F, and serum LDL, but reduced serum triglyceride.

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.

Efficacy of methyl ester of conjugated linoleic acid (t10,c12 isomer) for sows and cows for reproduction.

A mixture of methylated conjugated linoleic acid (CLA) isomers (t10,c12 and c9,t11) in equal proportions is the subject of this assessment. The active substance is considered to be CLA (t10,c12) methyl ester (ME). The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) of EFSA previously issued an opinion on the safety and efficacy of the product, in which it could not conclude on the efficacy of this additive for sows for reproduction and for cows for reproduction. The European Commission asked EFSA to deliver an opinion on the efficacy of this additive for sows and cows for reproduction, based on additional data submitted by the applicant. The FEEDAP Panel has performed the assessment of the new data following an approach in line with the principles laid down in Regulation (EC) No 429/2008 and the relevant guidance documents. In relation to the data on efficacy in sows for reproduction, owing to methodological shortcomings of the study submitted, including the duration of the study and the limited biological relevance of the effect observed, the FEEDAP Panel cannot conclude on the efficacy of CLA (t10,c12)‐ME for sows for reproduction. The data related to dairy cows indicate that dietary CLA (t10,c12)‐ME supplementation in the late dry period and/or lactation period showed an increase of the probability of pregnancy and a reduction of time to conception in the same reproductive cycle. However, considering that the minimum duration of efficacy studies for reproductive parameters is of at least two reproductive cycles, the FEEDAP Panel is not in a position to conclude on the efficacy of the additive for cows for reproduction.

Gender differences in the myocardial response to dietary CLA isomers during diabetes

This study was undertaken to examine if conjugated linoleic acid (CLA) isomers c9,t11 and t10,c12, provide protection against cardiac dysfunction in diabetic male and female rats. Diabetes was induced by an intravenous injection of streptozotocin (65 mg/kg body weight) in male and female rats. Four wks after the induction of diabetes, the animals were treated daily for 4 wks with or without 0.5% of each CLA isomer by oral gavage. Eight wks diabetes was associated with elevated levels of plasma total cholesterol, HDL-cholesterol, triglycerides and glucose as well as depressed rate of cardiac relaxation (-dP/dt) in both male and female animals. However, unlike females, male diabetic rats showed an increase in heart weight: body weight ratio and decreased rates of cardiac contraction (+dP/dt) and fractional shortening (FS). Both CLA isomers improved the lipid profile in male diabetic rats, whereas only CLA c9,t11 isomer improved the lipid profile in females. CLA intervention did not affect blood glucose levels in male or female diabetic animals. While CLA c9,t11 isomer improved ± dP/dt in the male rats, a deterioration of +dP/dt and -dP/dt in the female diabetic rats was observed. Although FS was normalized by both CLA isomers in males, CLA t10,c12 isomer depressed FS in the female diabetic rats. CLA treatment normalized GLUT 4 gene expression levels, but markedly increased insulin receptor gene expression in the heart of male diabetic rats. These data suggest that, unlike females, improved myocardial function in male diabetic rats in response to CLA may be related to a favorable shift in myocardial energetics.

Feeding Conjugated Linoleic Acid without a Combination of Medium-Chain Fatty Acids during Late Gestation and Lactation Improves Pre-Weaning Survival Rates of Gilt and Sow Progeny.

Simple SummaryA number of feeding strategies have been used in attempts to improve performance of progeny born to primiparous sows, which are born lighter, grow slower, and have higher rates of mortality than progeny born to older sows. The current study examined whether feeding conjugated linoleic acid (CLA) or a commercial medium-chain fatty acid (MCFA) product alone or in combination to primiparous and multiparous sows improved pre-weaning growth and survival of their progeny. Feeding CLA or MCFA failed to improve reproductive performance of primiparous or multiparous sows or the performance of their progeny during lactation, and there was no added benefit of feeding these products for gilt progeny. However, feeding CLA alone improved the survival of gilt and sow progeny. Further examination of the different inclusion levels and the timing of CLA feeding may be required in order for the use of this additive to be more efficacious.Feeding conjugated linoleic acid (CLA) or medium-chain fatty acids (MCFA) to dams has been shown to improve progeny growth and survival, and hence may be particularly advantageous to gilt progeny. Primiparous (n = 129) and multiparous sows (n = 123; parities 3 and 4) were fed one of four diets from day 107 of gestation (107.3 ± 0.1 days) until weaning (day 27.2 ± 0.1 of lactation): (i) control diet; (ii) 0.5% CLA diet; (iii) 0.1% MCFA diet; and (iv) equal parts of (ii) and (iii). Progeny performance data were collected and, from a subset of sows (n = 78) and their piglets (n = 144), a colostrum (day 0), milk (day 21), and piglet serum sample (day 3) were analyzed for immunoglobulin G and several selected metabolites. Liveborn pre-weaning mortality tended to be lowest (p = 0.051) in piglets from sows fed 0.5% CLA. However, sows fed the CLA diet had more (p = 0.005) stillbirths than those on the other diets. There were few effects of diet or the dam parity x diet interaction (p ≥ 0.05) on other parameters. Overall, feeding CLA or MCFA did not improve the performance of primiparous sows, multiparous sows, or their progeny.

Effects of Dietary Conjugated Linoleic Acid and Selected Vegetable Oils or Vitamin E on Fatty Acid Composition of Hen Egg Yolks

Abstract The objective of this study was to produce eggs enriched with conjugated linoleic acid (CLA) and ameliorate their fatty acid profile using the appropriate combination of dietary CLA with or without vegetable oils (olive oil or rapeseed oil) and vitamin E. In Experiment 1, 25-week-old laying hens were randomly distributed into eight groups of nine. Birds were fed with a standard diet with four different levels of CLA (0.0, 0.5, 0.75, 1.0%) and vegetable oils (olive oil or rapeseed oil, both in the amount of 1.46%). In Experiment 2, hens were randomly distributed into 12 groups of nine. The same four levels of CLA with three doses of vitamin E (0, 150, 300 mg/kg of diet) were applied. In both experiments, eggs were collected twice (at 4 and 8 weeks) for fatty acid profiling using GCMS. The differences between treatment means were considered significant at P&lt;0.05. CLA treatments significantly increased the content of CLA, saturated fatty acids (SFA), and significantly decreased the content of monounsaturated fatty acids (MUFA) in the egg yolk, whereas levels of polyunsaturated fatty acids (PUFA) were unaffected. The vegetable oils used did not prevent the negative effects of CLA effectively. Only after eight weeks of experiment 1 SFA levels were significantly lower, but MUFA levels were significantly higher in groups fed with rapeseed oil compared to groups fed with olive oil. In experiment 2, the addition of vitamin E to the hen diet did not have an essential influence on the lipid profile of egg yolks.

Effect of dietary conjugated linoleic acid supplementation during late gestation on colostrum yield, fatty acid composition, and IgG concentrations in primiparous sows

This experiment was conducted to evaluate the effects of dietary conjugated linoleic acid (CLA) supplementation during late gestation on reproductive performance, colostrum yield, colostral fatty acid composition, and immunoglobulin G (IgG) concentrations in primiparous sows. Twenty-four primiparous Landrace × Large White pregnant sows were randomly selected and assigned to four dietary treatments: 0% (control), 0.75%, 1.50%, and 2.25% CLA supplementation from day 85 of gestation to parturition. During lactation, all sows were fed the same commercial diet. The preweaning mortality of suckling piglets born to dams fed supplemental CLA did decrease linearly (P = 0.01) during lactation. Administration of CLA during gestation increased linearly (P &lt; 0.01) total saturated fatty acids and decreased linearly (P &lt; 0.01) monounsaturated fatty acids and polyunsaturated fatty acids in colostrum. The concentrations of CLA isomers were higher (P &lt; 0.01) in colostrum from primiparous sows fed CLA diets than in the control group. Feeding CLA increased (P &lt; 0.05) colostral IgG concentrations, as well as that in the serum of neonatal piglets. In conclusion, 2.25% CLA supplementation in the diet of primiparous sows during late gestation could improve the passive immunity through colostral IgG and the survival of suckling piglets.