Cis-12 Conjugated Linoleic Acid Research Articles

Trans 10, cis 12-conjugated linoleic acid in low concentration reduces while in high concentration enhances adipocyte metabolism but effectively improves hepatic steatosis of obese mice.

Trans 10, cis 12-conjugated linoleic acid (t10c12-CLA)-producing mice were used to investigate the anti-obesity of obese males. Compared to wild-type littermates, high concentration t10c12-CLA in biallelic Pai/Pai mice reduced fat by up-regulation lipid metabolism in white adipose tissue (WAT). In contrast, low concentration t10c12-CLA in monoallelic Pai/wt mice could not reduce fat for down-regulation lipid metabolism in WAT. Simultaneously, t10c12-CLA enhanced thermogenesis and beta-oxidation in brown adipose tissue, alleviated steatosis by declining lipid metabolism in the liver, and lowered circulating triglycerides. On the other hand, low concentration t10c12-CLA specifically resulted in decreased circulating fibroblast growth factor 21, elevated glucose and high-density lipoprotein, whereas high concentration t10c12-CLA specifically increased circulating and hepatic cholesterol levels via up-regulation of low-density lipoprotein receptor in the liver. In conclusion, high concentration t10c12-CLA enhances local lipid metabolism in WAT and leads to fat loss, whereas low concentration t10c12-CLA attenuates the enzymic activities in WAT and fails to reduce fat. T10c12-CLA can effectively and concentration independently improve steatosis by attenuating hepatic lipid metabolism. These results suggest that low concentration of t10c12-CLA is beneficial, but high concentration is unfavorable to obese male mammals.

Potential involvement of PPARs in the inhibition of mammary lipid synthesis during diet-induced milk fat depression

The objective of this study was to evaluate the possible role of the peroxisome proliferator-activated receptors (PPARs: PPAR-α, PPAR-β/δ, and PPAR-γ) in diet and conjugated linoleic acid (CLA)-induced milk fat depression (MFD) in dairy cows. We hypothesized that the expression of PPARs, which regulate lipid metabolism and bind to polyunsaturated fatty acids, could be modulated by biohydrogenation intermediates that induce MFD, thereby interfering with milk fat synthesis. First, tissue profiling revealed that PPAR-α and PPAR-β/δ had low expression in mammary tissue compared with the liver. A comparison of lactating and nonlactating tissue from the same cows showed that expression of the PPARs did increase during lactation. Mammary expression of the PPARs during MFD was then observed in 9 mid-lactation cows in a 3x3 Latin square design with MFD induced by a 3-d intravenous infusion of trans-10,cis-12 CLA or feeding a high-oil/low-forage diet. The expression of the PPARs remained largely unaltered during CLA and diet-induced MFD, except for an increase in PPAR-α target genes CPT1A and ACADVL that are involved in β-oxidation. The interaction of PPAR-γ chemical agonist Troglitazone and antagonist T0070907 and CLA was then investigated in bovine mammary epithelial cells (MAC-T). The activation and inhibition of PPAR-γ did not overcome trans-10,cis-12 CLA inhibition of lipogenesis despite the agonist stimulating PPAR-γ expression. Furthermore, PPAR-γ activation did not modify the expression of lipogenic genes. Overall, the results fail to support a functional role of the PPARs in the inhibition of lipogenesis during MFD in dairy cows.

Trans-10 shifted ruminal biohydrogenation and its implications for ruminant milk and meat fat content and quality

Feeding high-grain diets is a common practice in intensive ruminant production systems to meet animal energy requirements and maximize feed efficiency. One of the consequences of these diets is trans (t)10 shifted ruminal biohydrogenation, which includes increased formation of t10-18:1 and t10,cis (c)12-conjugated linoleic acid (t10,c12-CLA) at the expense of t11-18:1 and c9,t11-CLA. In dairy cows, the t10 shift has been associated with milk fat depression. In beef cattle, the t10 shift has not been associated with negative effects on animal performance or marbling fat deposition, however, it may negatively impact meat fat eating quality by decreasing its cis monounsaturated fatty acid to saturated fatty acid ratio. Finally, the t10 shift increases t10-18:1 accumulation in ruminant-derived foods (dairy, beef and lamb) which at high enough levels may compromise the nutritional quality of these foods. The present review will cover our current understanding of the rumen microbes involved in the t10 shift and its implications for milk fat synthesis and beef fat quality.

Transgenic female mice producing trans 10, cis 12-conjugated linoleic acid present excessive prostaglandin E2, adrenaline, corticosterone, glucagon, and FGF21

Dietary trans 10, cis 12-conjugated linoleic acid (t10c12-CLA) is a potential candidate in anti-obesity trials. A transgenic mouse was previously successfully established to determine the anti-obesity properties of t10c12-CLA in male mice that could produce endogenous t10c12-CLA. To test whether there is a different impact of t10c12-CLA on lipid metabolism in both sexes, this study investigated the adiposity and metabolic profiles of female Pai mice that exhibited a dose-dependent expression of foreign Pai gene and a shift of t10c12-CLA content in tested tissues. Compared to their gender-match wild-type littermates, Pai mice had no fat reduction but exhibited enhanced lipolysis and thermogenesis by phosphorylated hormone-sensitive lipase and up-regulating uncoupling proteins in brown adipose tissue. Simultaneously, Pai mice showed hepatic steatosis and hypertriglyceridemia by decreasing gene expression involved in lipid and glucose metabolism. Further investigations revealed that t10c10-CLA induced excessive prostaglandin E2, adrenaline, corticosterone, glucagon and inflammatory factors in a dose-dependent manner, resulting in less heat release and oxygen consumption in Pai mice. Moreover, fibroblast growth factor 21 overproduction only in monoallelic Pai/wt mice indicates that it was sensitive to low doses of t10c12-CLA. These results suggest that chronic t10c12-CLA has system-wide effects on female health via synergistic actions of various hormones.

Trans 10, cis 12-conjugated linoleic acid reduced reproductive ability by disrupting the estrus cycle in female mice

Trans 10, cis 12-conjugated linoleic acid reduced reproductive ability by disrupting the estrus cycle in female mice

Progress of Conjugated Linoleic Acid on Milk Fat Metabolism in Ruminants and Humans.

As a valuable nutrient in milk, fat accounts for a significant proportion of the energy requirements of ruminants and is largely responsible for determining milk quality. Fatty acids (FAs) are a pivotal component of milk fat. Conjugated linoleic acid (CLA) is one of the naturally occurring FAs prevalent in ruminant dairy products and meat. Increasing attention has been given to CLA because of its anti-cancer, anti-inflammatory, immune regulation, and lipid metabolism regulation properties, and these benefits potentially contribute to the growth and health of infants. In breast milk, CLA is present in trace amounts, mainly in the form of cis-9, trans-11 CLA. Notably, cis-9, trans-11 CLA improves the milk fat rate while trans-10, cis-12 CLA inhibits it. Apart from having multiple physiological functions, CLA is also a pivotal factor in determining the milk quality of ruminants, especially milk fat rate. In response to growing interest in green and healthy functional foods, more and more researchers are exploring the potential of CLA to improve the production performance of animals and the nutritional value of livestock products. Taken together, it is novel and worthwhile to investigate how CLA regulates milk fat synthesis. It is the purpose of this review to clarify the necessity for studying CLA in ruminant milk fat and breast milk fat.

Transgenic mice producing the trans 10, cis 12-conjugated linoleic acid present reduced adiposity and increased thermogenesis and fibroblast growth factor 21 (FGF21)

Trans 10, cis 12-conjugated linoleic acid (t10c12-CLA) from ruminant-derived foodstuffs can induce body fat loss after oral administration. In the current study, a transgenic mouse that produced t10c12-CLA had been generated by inserting the Propionibacterium acnes isomerase (Pai) expression cassette into the Rosa26 locus, and its male offspring were used to elucidate the enduring influence of t10c12-CLA on overall health. Compared to their wild-type (wt) C57BL/6J littermates, both biallelic Pai/Pai and monoallelic Pai/wt mice exhibited reduced plasma triglycerides levels, and Pai/wt mice exclusively showed increased serum fibroblast growth factor 21. Further analysis of Pai/Pai mice found a decrease in white fat and an increase in brown fat, with more heat release and less physical activity. Analysis of Pai/Pai brown adipose tissues revealed that hyperthermia was associated with the over-expression of carnitine palmitoyltransferase 1B, uncoupling proteins 1 and 2. These findings suggest that the systemic and long-term impact of t10c12-CLA on obesity might be mediated through the pathway of fibroblast growth factor 21 when low doses are administered or through enhanced thermogenesis of brown adipose tissues when high doses are employed.

Abomasal infusion of essential fatty acids and conjugated linoleic acid during late pregnancy and early lactation affects immunohematological and oxidative stress markers in dairy cows

Oxidative stress and inflammation, as natural parts of metabolic adaptations during the transition from late gestation to early lactation, are critical indicators of dairy cows' metabolic health. This study was designed to investigate the effects of abomasal infusion of essential fatty acids (EFA), particularly α-linolenic acid, and conjugated linoleic acid (CLA) on plasma, erythrocyte, and liver markers of oxidative stress in dairy cows during the transition period. Rumen-cannulated German Holstein cows (n = 38) in their second lactation (11,101 ± 1,118 kg milk/305 d, mean ± standard deviation) were abomasally infused with one of the following treatments from d -63 antepartum until d 63 postpartum (PP): CTRL (n = 9; 76 g/d coconut oil); EFA (n = 9; 78 g/d linseed plus 4 g/d safflower oil); CLA (n = 10; isomers cis-9,trans-11 and trans-10,cis-12 CLA; 38 g/d); and EFA+CLA (n = 10; 120 g/d). Hematological parameters as well as markers of oxidative status were measured in plasma, erythrocytes, and liver before and after calving. Immunohematological parameters, including erythrocyte number, hematocrit, hemoglobin, mean corpuscular hemoglobin, leukocytes, and basophils, were affected by time, and their peak levels were observed on the day after calving. The oxidative stress markers glutathione peroxidase 1 and reactive oxygen metabolites in plasma and erythrocytes were both affected by time, exhibiting the highest levels on d 1 PP, whereas β-carotene, retinol, and tocopherol were at their lowest levels at the same time. Immunohematological parameters were only marginally affected by fatty acid treatment in a time-dependent manner. As such, lymphocyte and atypical lymphocyte counts were both significantly highest in the groups that received EFA at d 1 PP. Moreover, EFA supplementation increased the mean corpuscular volume and showed a trend for induction of mean corpuscular hemoglobin compared with the CLA group during the transition period. The PP mean thrombocyte volume was higher in the EFA than in the CLA group (except for d 28) and both EFA and CLA reduced number of thrombocytes and thrombocrit at distinct time points. Hepatic mRNA abundance of markers related to oxidative status, including glutathione peroxidase (GPX-1) and catalase (CAT), was lower (P < 0.05) in EFA-treated than non-EFA-treated cows at d 28 PP. Dairy cows at the onset of lactation were characterized by induced markers of both oxidative stress and inflammation. Supplementing EFA and CLA had minor and time-dependent effects on markers of oxidative stress in plasma, erythrocytes, and liver. A comparison of EFA supplementation with CLA or CTRL showed higher immunohematological response at d 1 PP and lower hepatic antioxidant levels by d 28 PP. Supplementation with EFA+CLA had only a minor effect on oxidative markers, which were more similar to those with the EFA treatment. Altogether, despite the time-dependent differences, the current findings show only minor effects of EFA and CLA supplementation in the prevention of early lactation-induced oxidative stress.

Rumen microbiota-host transcriptome interaction mediates the protective effects of trans-10, cis-12 CLA on facilitating weaning transition of lambs.

Developing alternatives to antibiotics for prevention of gastrointestinal dysbiosis in early-weaning farmed animals is urgently needed. This study was to explore the potential effects of trans-10, cis-12 conjugated linoleic acid (CLA) on maintaining ruminal homeostasis of young ruminants during the weaning transition period. Thirty neonatal lambs were selected (6 lambs per group) and euthanized for rumen microbial and epithelial analysis. The lambs were weaned at 28d and experienced the following 5 treatments: euthanized on d 28 as the pre-weaning control (CON0), fed starter feed for 5 (CON5) or 21 (CON21) d, fed starter feed with 1% of CLA supplemented for 5 (CLA5) or 21 (CLA21) d. Results showed that the average daily weight gain and dry matter intake were significantly higher in CLA5 than CON5 group. As compared with the CON5 and CON21 group, the relative abundances of volatile fatty acid (VFA) producing bacteria including Bacteroides, Treponema, Parabacteroides and Anaerovibrio, as well as the concentrations of acetate, butyrate and total VFA were significantly increased in CLA5 and CLA21 group, respectively. Integrating microbial profiling and epithelial transcriptome results showed that 7 downregulated inflammatory signaling-related host genes IL2RA, CXCL9, CD4, CCR4, LTB, SPP1, and BCL2A1 with CLA supplementation were significantly negatively correlated with both VFA concentration and VFA producing bacteria, while 3 (GPX2, SLC27A2 and ALDH3A1) and 2 (GSTM3 and GSTA1) upregulated metabolism-related genes, significantly positively correlated with either VFA concentration or VFA producing bacteria, respectively. To confirm the effects of CLA on epithelial signal transduction, invitro experiment was further conducted by treating rumen epithelial cells without or with IL-17A+TNF-α for 12h after pretreatment of 100μM CLA or not (6 replicates per treatment). The results demonstrated the anti-inflammatory effect of CLA via suppressing the protein expression of NF-кB p-p65/p65 with the activation of peroxisome proliferator-activated receptor gamma (PPARγ). In conclusion, CLA supplementation enhanced the ruminal microbiota-driven transcriptional regulation in healthy rumen epithelial development via rumen VFA production, and CLA may therefore serve as an alternative way to alleviate early-weaning stress and improve physiological and metabolic conditions of young ruminants.

Conjugated linoleic acid trans-10, cis-12 increases the expression of genes from cell cycle progression and cis-9, trans-11 stimulates apoptotic genes in different mammary tumor explants of female dogs.

The conjugated linoleic acid (CLA) isomer cis-9, trans-11 is an anticarcinogen that inhibits cell proliferation and/or induces apoptosis of tumor cells. The objective of this study was to evaluate the expression of genes responsible for cell cycle regulation and apoptosis in tumor explants of mammary anaplastic carcinoma (AC) and mammary tubulopapillary carcinoma (TC) cultured in vitro with the CLA isomers cis-9, trans-11 and trans-10, cis-12. In this study we used mammary explants from two adult female dogs that revealed two types of malignant tumors: (a) anaplastic mammary carcinoma (AC) and (b) mammary tubulopapillary carcinoma (TC). The explants (n = 6 per treatment) had an average weight of 80.0 ± 2.0mg and were cultured for 24h in 35mm culture plates under the following treatments: (a) Control: Culture medium + fatty acid free bovine serum albumin (BSA); (b) Culture medium + cis-9, trans-11 CLA (75 µM) diluted with fatty acid free bovine serum albumin (BSA), and; (c) Culture medium + trans-10, cis-12 CLA (75 µM) diluted with fatty acid free bovine serum albumin (BSA). After that, total RNA was extracted, complementary DNA was synthesized (cDNA), and quantitative analysis by real-time polymerase chain reaction (RT-qPCR) was conducted. Data were analyzed using the MIXED procedure of SAS. Compared with the Control, the CLA trans-10, cis-12 treatment decreased expression of the gene encoding the p53 by 20% (P = 0.02), Caspase-3 by 25% (P = 0.06) and Bax by 51% (P = 0.001) in AC. The CLA cis-9, trans-11 increased the gene expression of proapoptotic protein Bax in TC by 68% (P = 0.01), but increased the expression of the antiapoptotic Bcl2 gene in AC by 72% (P = 0.006). The CLA cis-9, trans-11 stimulates apoptotic genes in mammary tubulopapillary carcinoma, but has a contrary effect on the anaplastic carcinoma, and the CLA trans-10, cis-12 stimulates cell cycle progression genes and may have an antiapoptotic effect, mainly in mammary anaplastic carcinoma.

RAPID METHOD FOR SIMULTANEOUS DETERMINATION OF CIS-9, TRANS-11 AND TRANS-10, CIS-12 CONJUGATED LINOLEIC ACID ISOMERS IN MILK BY GC-FID

Ruminant milk is the lead source of conjugated linoleic acid (CLA) in the human diet, with cis-9, trans-11 CLA being the major among all. Small amounts of trans-10, cis-12 CLA are also found in synthetic supplements. Since both isomers are biologically active with potential health benefits, there is great interest in quantifying them for quality control routines. An alternative method for the analysis of the aforementioned CLAs by fast gas chromatography (GC) is discussed in the present study. The fatty acid methyl ester mixture obtained by alkaline catalysis was injected into a GC equipped with a flame ionization detector (FID) and fitted with an ionic liquid SLB-IL111 chromatographic column (15 m × 0.10 mm × 0.08 µm). Separation was achieved in less than 5 min using a 168 °C isotherm run. Both CLA isomers were quantified by using of single point standard addition statistical approach. Results were contested to those obtained using the recommended 100 m long CP-Sil88 capillary column and none evidence of significant differences was found within 95% confidence interval. Therefore, the proposed method could be valuable to focused regulatory routines of large numbers of samples with greater analytical frequency.

Enhanced Soluble Expression of Linoleic Acid Isomerase by Coordinated Regulation of Promoter and Fusion Tag in Escherichia coli.

PAI is a linoleic acid isomerase from Propionibacterium acnes and is the key enzyme in the synthesis of trans10, cis12-conjugated linoleic acid. However, the majority of the expressed PAI in Escherichia coli occurs in its nonfunctional form in inclusion bodies, limiting the biosynthesis of conjugated linoleic acid. In an attempt to improve the solubility of recombinant PAI in Escherichia coli, three promoters representing different transcriptional strengths (T7, CspA, and Trc), paired with three fusion tags, (His6, MBP, and Fh8), respectively, were investigated in this study. Among the nine recombinant strains, Escherichia coli BL21 (DE3) (pET24a-Mpai), containing the T7 promoter and MBP fusion tag, led to a considerable increase in PAI solubility to 86.2%. MBP-PAI was purified 41-fold using affinity column chromatography. The optimum catalytical conditions of MBP-PAI were 37 °C and pH 7.5 with the addition of 1 mmol/L Tween-20. Most of the tested metal ions inhibited MBP-PAI activity. The apparent kinetic parameters (Km and Vmax) were measured with linoleic acid concentrations ranging from 71 μM to 1428 μM. The substrate linoleic acid did not exert any inhibitory effect on MBP-PAI. The Km of MBP-PAI was 253.9 μmol/L, and the Vmax was 2253 nmol/min/mg. This study provided a new method for improving the solubility of the recombinant linoleic acid isomerase in Escherichia coli.

Barley β-glucan for conjugated linoleic acid (CLA) production by Bifidobacterium animalis subsp. Lactis: Fatty acid variation and bacterial viability study

In the present study, production of two isomers (cis-9, trans-11 and trans-10, cis-12) of conjugated linoleic acid (CLA) by Bifidobacterium animalis subsp. Lactis BB12 was investigated in organic and conventional milk in the presence of barley derived β-glucan. Fatty acid profile, acidification profile, cell enumeration and lactose content were determined for fermented conventional and organic milk, before and after 30 h fermentation in 30 °C. Viscometery and sensory evaluations were also performed. The results showed higher counts of Bifidobacterium animalis subsp. Lactis BB12, and viscosity in organic milk. Also, organic fermented milk offered higher CLA as well as polyunsaturated fatty acids values and a lower level of saturated fatty acids in comparison to conventional fermented milk. Cis-9, trans-11 CLA, trans-10, cis-12 CLA and polyunsaturated fatty acids values, bacterial count and viscosity in organic milk containing β-glucan were 28%, 39%, 33%, one log CFU/mL and 59% higher than the samples without β-glucan, respectively. Although these results were obtained for conventional milk, the variation percentage in the organic milk was significantly more than the conventional milk. In addition, the total lactose content in organic and conventional milk containing β-glucan was 19% and 12% lower than the samples without prebiotic.

Modeling the effect of trans-10 fatty acids associated with milk fat depression in dairy goats and ewes supplemented with trans-10, cis-12 conjugated linoleic acid

Under certain conditions, ruminal biohydrogenation produces trans fatty acids (FA), such as trans-10, cis-12 conjugated linoleic acid (CLA), and trans-10 18:1 (T10), which are associated with a phenomenon known as milk fat depression syndrome (MFD). The effect of milk trans-10 FA on MFD in small ruminants has been quantified using different regression models. However, no study has defined a regression that produces the most accurate statistical model. In addition, interspecies differences based on the relationship between milk trans-10 FA and milk fat content are yet to be evaluated. Therefore, we aimed to determine the best model that quantifies the relationship between MFD and trans-10 FA (CLA or T10) in goats and ewes, and to test the hypothesis that there is a species-specific difference between goats and ewes in the magnitude of milk fat loss by one unit change of milk CLA and/or T10 concentration. Previously published data (106 observations for goats and 68 for ewes) were used to estimate, by simple linear and nonlinear regressions, the following response variables: milk fat yield (FY; g/d), percentage change in milk fat yield (CFY;%), milk fat concentration (FC;%), and percentage change in milk fat concentration (CFC;%). The models with FC as response variable showed the best prediction adjustment for both species. However, the nonlinear relationship between FC and T10 proved to be the most accurate model, whereas CLA was the best regressor for ewes. In addition, there was no species-specific difference in the magnitude by which milk fat was reduced as a function of the milk CLA and T10 content.

Cellular detection of the chemokine receptor CXCR4 in bovine mammary glands and its distribution and regulation on bovine leukocytes

Mastitis has a high incidence in dairy cows. Experimental infection with Escherichia coli increased the number of leukocytes in milk and the gene expression of the chemokine receptor CXCR4 in mammary gland tissues. A link between CXCR4 expression and lipopolysaccharide sensing was demonstrated in other species using in vitro models. The receptor that binds the chemokine stomal cell-derived factor 1 might be associated with the inflammatory response in bovine mammary glands. However, studies in cows are rare, and data on the localization of CXCR4 in bovine mammary glands and its distribution in bovine leukocytes are lacking. Fatty acids (FA) affect the inflammatory response. In human peripheral blood monocytes, exposure to conjugated linoleic acids (CLA) decreases the expression of CXCR4, leading to a decreased inflammatory response in these cells. In this study, we analyzed the expression of CXCR4 in the mammary glands of dairy cows by immunohistochemistry (n = 5) and laser capture microdissection followed by qualitative PCR (n = 3). We characterized the surface expression of CXCR4 on bovine leukocytes, including monocyte subpopulations, first by flow cytometry (n = 5) and then confirmed these results by Western blotting (n = 3). Rumen fistulated dairy cows (n = 4; 126 ± 4 d in milk) were fitted with abomasal infusion tubes, arranged in a 4 × 4 Latin square design, and supplemented for 6 wk twice daily with rising doses of FA followed by a 3-wk washout period. Then, CXCR4 expression on leukocytes was analyzed. The cows received a corn-based diet and were supplemented with coconut oil delivering medium-chain FA (38 g/d), linseed-safflower oil mix delivering n-3 FA (EFA, 39 g of linseed oil and 2 g of safflower oil per day), Lutalin (cis-9,trans-11 and trans-10,cis-12 CLA, 5 g/d; BASF), and EFA + CLA. In the bovine mammary gland, the epithelial cells of the lactiferous duct, but not alveolar epithelial cells, showed clear CXCR4 protein and mRNA signals. Among the leukocyte subsets, monocytes displayed the highest percentage of CXCR4-positive cells (87%), whereas circulating neutrophils showed almost no CXCR4 surface expression (3%) but stored the receptor intracellularly. The percentage of CXCR4-positive leukocytes was not affected by the different FA supplements, but FA supplementation reduced the receptor abundance per cell (40% on average). In conclusion, CXCR4 was clearly detected in the lactiferous duct cells of the mammary gland but not in the alveolar epithelial cells. Compared with other leukocytes, bovine monocytes showed the highest signal intensity of CXCR4 on their surface, whereas granulocytes stored CXCR4 intracellularly. Supplementation with all the FA reduced the surface expression of CXCR4 per leukocyte and could therefore potentially affect the inflammatory status associated with the surface expression of CXCR4. The importance of our observations should be verified in cows with mastitis in the future.

Stearic acid does not overcome conjugated linoleic acid trans-10, cis-12-induced milk fat depression in lactating ewes.

The objective of this study was to test the hypothesis that stearic acid (SA) supplementation increases milk fat content and overcomes the antilipogenic effects of trans-10, cis-12 conjugated linoleic acid (CLA) in lactating ewes. Twenty-eight Lacaune ewes (36 (sd 2) days in lactation; 70·5 (sd) 9·6 kg of body weight), producing 1·8 (sd 0·4) kg of milk/d, were used in a completely randomised design (seven ewes/treatment) for 21 d. The treatments were: (1) Control; (2) CLA (6·4 g/d of trans-10, cis-12 CLA); (3) SA (28 g/d of SA) and (4) SA in association with trans-10, cis-12 CLA (CLASA; 6·4 g/d of trans-10, cis-12 CLA plus 28 g/d of SA). All data were analysed using a mixed model that included the fixed effect of treatment and the random effect of ewe. SA did not alter milk fat content and yield relative to Control (91·9 v. 91·2 (sd 4·1) g/d). CLASA was not able to overcome the reduction in fat content and fat yield induced by CLA (75 v. 82 (sd 0·14) g/d). SA increased the relative abundance of CD36, fatty acid-binding protein 4 (FABP4) and PPAR-γ mRNA by 140, 112 and 68 % compared with CLASA. SA also reduced the relative abundance of acetyl-CoA carboxylase α promoter II and stearoyl-CoA desaturase (SCD) when compared with Control (45 and 39 %). Compared with CLA, CLASA treatment had no effect on the mRNA abundance of fatty acid synthase, lipoprotein lipase, CD36, SCD, FABP4, acylglycerolphosphate acyltransferase 6, sterol regulatory element-binding protein 1 and PPAR-γ. In conclusion, SA supplementation did not increase milk fat synthesis and did not overcome the CLA-induced milk fat depression when associated with trans-10, cis-12 CLA.

Camel Milk Composition and Microbial Reduction with Different Pasteurization Methods

The objective of this study was to investigate the efficacy of different thermal pasteurization methods on (1) the survival of the total aerobic bacteria, E. coli O157: H7, in camel milk, and (2) the camel milk components such as the fatty acid profile, lipid peroxidation, protein fractions, and the composition of volatile compounds. Samples of camel milk (N=9) were pasteurized at 65°C/30 min (PAST-1), 72°C/5 min (PAST-2), and 80°C/15 min (PAST-3). The survival of E. coli O157: H7 was evaluated using the traditional plate count agar (PCA) method while the total aerobic bacteria were enumerated using the petrifilm aerobic count plates (ACP). Complete elimination (P10 CFU/ml reduction). All pasteurization methods had a significant (PE. coli O157: H7 resulting in a 6 log10 CFU/ml reduction. There were no significant (P>0.05) differences in the fatty acid profile including the cis-9, trans-11 conjugated linoleic acid (CLA), and trans-10, cis-12 CLA, and the lipid peroxidation products between raw and pasteurized milk samples. The milk protein profile was marginally altered by PAST-2 and PAST-3 treatments but not PAST-1. Thirty-four volatile compounds (VCs) were detected in the raw milk samples compared to 29 VCs in the pasteurized milk samples. Pasteurization treatments altered the concentrations of some milk VCs, increasing the Heptanal, Tridecanal, and Undecanal while decreasing the 2-Decanal and 2-Undecanal. This study shows that PAST-1 and PAST-3 treatments are more effective than PAST-2 at inactivating total aerobic bacteria. Additionally, the absence of significant changes in milk compositions indicates that PAST-1 and PAST-3 could be applied without affecting the nutritional value of camel milk.

Effect of maternal supplementation with essential fatty acids and conjugated linoleic acid on metabolic and endocrine development in neonatal calves

We tested the hypothesis that the maternal supply of essential fatty acids (EFA), especially α-linolenic acid, and conjugated linoleic acid (CLA), affects glucose metabolism, the endocrine regulation of energy metabolism and growth, and the intestinal development of neonatal calves. We studied calves from dams that received an abomasal infusion of 76 g/d coconut oil (CTRL; n = 9), 78 g/d linseed oil and 4 g/d safflower oil (EFA; n = 9), 38 g/d Lutalin (BASF SE) containing 27% cis-9,trans-11 and trans-10,cis-12 CLA (CLA; n = 9), or a combination of EFA and CLA (EFA+CLA; n = 11) during the last 63 d of gestation and early lactation. Calves received colostrum and transition milk from their own dam for the first 5 d of life. Insulin-like growth factor (IGF)-I, leptin, and adiponectin concentrations were measured in milk. Blood samples were taken before first colostrum intake, 24 h after birth, and from d 3 to 5 of life before morning feeding to measure metabolic and endocrine traits in plasma. On d 3 of life, energy expenditure was evaluated by a bolus injection of NaH13CO3 and determination of CO2 appearance rate. On d 4, additional blood samples were taken to evaluate glucose first-pass uptake and 13CO2 enrichment after [13C6]-glucose feeding and intravenous [6,6-2H2]-glucose bolus injection, as well as postprandial changes in glucose, nonesterified fatty acids (NEFA), insulin, and glucagon. On d 5, calves were killed 2 h after feeding and samples of small intestinal mucosa were taken for histomorphometric measurements. The concentrations of IGF-I, adiponectin, and leptin in milk decreased during early lactation in all groups, and the concentrations of leptin in first colostrum was higher in EFA than in CTRL cows. Plasma glucose concentration before first colostrum intake was higher in EFA calves than in non-EFA calves and was lower in CLA calves than in non-CLA calves. Plasma IGF-I concentration was higher on d 1 before colostrum intake in EFA calves than in EFA+CLA calves and indicated an overall CLA effect, with lower plasma IGF-I in CLA than in non-CLA calves. Postprandial NEFA concentration was lowest in EFA and CLA calves. The postprandial rise in plasma insulin was higher in EFA than in non-EFA calves. Plasma adiponectin concentration increased from d 1 to d 2 in all groups and was higher on d 3 in CLA than in non-CLA calves. Plasma leptin concentration was higher on d 4 and 5 in EFA than in non-EFA calves. Maternal fatty acid treatment did not affect energy expenditure and first-pass glucose uptake, but glucose uptake on d 4 was faster in EFA than in non-EFA calves. Crypt depth was lower, and the ratio of villus height to crypt depth was higher in the ilea of CLA than non-CLA calves. Elevated plasma glucose and IGF-I in EFA calves immediately after birth may indicate an improved energetic status in calves when dams are supplemented with EFA. Maternal EFA and CLA supplementation influenced postprandial metabolic changes and affected factors related to the neonatal insulin response.

Modulation of colostrum composition and fatty acid status in neonatal calves by maternal supplementation with essential fatty acids and conjugated linoleic acid starting in late lactation

Sufficient maternal supply of essential fatty acids (EFA) to neonatal calves is critical for calf development. In the modern dairy cow, EFA supply has shifted from α-linolenic acid (ALA) to linoleic acid (LA) due to the replacement of pasture feeding by corn silage-based diets. As a consequence of reduced pasture feeding, conjugated linoleic acid (CLA) provision by rumen biohydrogenation was also reduced. The present study investigated the fatty acid (FA) status and performance of neonatal calves descended from dams receiving corn silage-based diets and random supplementation of either 76 g/d coconut oil (CTRL; n = 9), 78 g/d linseed oil and 4 g/d safflower oil (EFA; n-6/n-3 FA ratio = 1:3; n = 9), 38 g/d Lutalin (BASF SE, Ludwigshafen, Germany) providing 27% cis-9,trans-11 and trans-10,cis-12 CLA, respectively (CLA; n = 9), or a combination of EFA and CLA (EFA+CLA; n = 11) in the last 9 wk before parturition and following lactation. The experimental period comprised the first 5 d of life, during which calves received colostrum and transition milk from their own dam. The nutrient compositions of colostrum and transition milk were analyzed. Plasma samples were taken after birth and before first colostrum intake and on d 5 of life for FA analyses of the total plasma fat and lipid fractions. Maternal EFA and CLA supplementation partly affected colostrum and transition milk composition but did not change the body weights of calves. Most EFA in calves were found in the phospholipid (PL) and cholesterol ester (CE) fractions of the plasma fat. Maternal EFA supplementation increased the percentage of ALA in all lipid fractions of EFA and EFA+CLA compared with CTRL and CLA calves on d 1 and 5, and the increase was much greater on d 5 than on d 1. The LA concentration increased from d 1 to 5 in the plasma fat and lipid fractions of all groups. The concentrations of docosapentaenoic acid, docosahexaenoic acid, and arachidonic acid in plasma fat were higher on d 1 than on d 5, and the percentage of n-3 metabolites was mainly increased in PL if dams received EFA. The percentage of cis-9,trans-11 CLA was higher in the plasma fat of EFA+CLA than CTRL calves after birth. By d 5, the percentages of both CLA isomers increased, leading to higher proportions in plasma fat of CLA and EFA+CLA than in CTRL and EFA calves. Elevated cis-9,trans-11 CLA enrichment was observed on d 5 in PL, CE, and triglycerides of CLA-treated calves, whereas trans-10,cis-12 CLA could not be detected in individual plasma fractions. These results suggest that an altered maternal EFA and CLA supply can reach the calf via the placenta and particularly via the intake of colostrum and transition milk, whereas the n-3 and n-6 FA metabolites partly indicated a greater transfer via the placenta. Furthermore, the nutrient supply via colostrum and transition milk might be partly modulated by an altered maternal EFA and CLA supply but without consequences on calf performance during the first 5 d of life.

Glucose metabolism and the somatotropic axis in dairy cows after abomasal infusion of essential fatty acids together with conjugated linoleic acid during late gestation and early lactation

Sufficient glucose availability is crucial for exploiting the genetic potential of milk production during early lactation, and endocrine changes are mainly related to repartitioning of nutrient supplies toward the mammary gland. Long-chain fatty acids, such as essential fatty acids (EFA) and conjugated linoleic acid (CLA), have the potential to improve negative energy balance and modify endocrine changes. In the present study, the hypothesis that combined CLA and EFA treatment supports glucose metabolism around the time of calving and stimulates insulin action and the somatotropic axis in cows in an additive manner was tested. Rumen-cannulated German Holstein cows (n = 40) were investigated from wk 9 antepartum (AP) until wk 9 postpartum (PP). The cows were abomasally supplemented with coconut oil (CTRL, 76 g/d); 78 g/d of linseed and 4 g/d of safflower oil (EFA); Lutalin (CLA, isomers cis-9,trans-11 and trans-10,cis-12 CLA, each 10 g/d); or the combination of EFA+CLA. Blood samples were collected several times AP and PP to determine the concentrations of plasma metabolites and hormones related to glucose metabolism and the somatotropic axis. Liver tissue samples were collected several days AP and PP to measure glycogen concentration and the mRNA abundance of genes related to gluconeogenesis and the somatotropic axis. On d 28 AP and 21 PP, endogenous glucose production (eGP) and glucose oxidation (GOx) were measured via tracer technique. The concentration of plasma glucose was higher in CLA than in non-CLA-treated cows, and the plasma β-hydroxybutyrate concentration was higher in EFA than in non-EFA cows on d 21 PP. The eGP increased from AP to PP with elevated eGP in EFA and decreased eGP in CLA-treated cows; GOx was lower in CLA than in CTRL on d 21 PP. The plasma insulin concentration decreased after calving in all groups and was higher in CLA than in non-CLA cows at several time points. Plasma glucagon and cortisol concentrations on d 21 PP were lower in CLA than non-CLA groups. The glucagon/insulin and glucose/insulin ratios were higher in CTRL than in CLA group during the transition period. Plasma IGF-I concentration was lower in EFA than non-EFA cows on d 42 AP and was higher during the dry period and early lactation in CLA than in non-CLA cows. The IGF binding protein (IGFBP)-3/-2 ratio in blood plasma was higher in CLA than in non-CLA cows. Hepatic glycogen concentration on d 28 PP was higher, but the mRNA abundance of PC and IGFBP2 was lower in CLA than non-CLA cows on d 1 PP. The EFA treatment decreased the mRNA abundance of IGFBP3 AP and PCK1, PCK2, G6PC, PCCA, HMGCS2, IGFBP2, and INSR at several time points PP. Results indicated elevated concentrations of plasma glucose and insulin along with the stimulation of the somatotropic axis in cows treated with CLA, whereas EFA treatment stimulated eGP but not mRNA abundance related to eGP PP. The systemic effects of the combined EFA+CLA treatment were very similar to those of CLA treatment, but the effects on hepatic gene expression partially corresponded to those of EFA treatment.