Preparation of Conjugated Linoleic Acid of High Purity and Its Apparent Kinetic Characteristics During Formation

Conjugated linoleic acid (CLA) is a fatty acid with physiological activities and potential application prospect. This paper focuses on the method of synthesis of conjugated linoleic acid of high purity and the process line and conditions for its purification that can be used in large scale production. CLA of more than 95% purity was prepared by means of urea adduct purification and conjugation using safflower oil as material. The total recovery of the product adds up to more than 48%. The reactive kinetics about linoleic acid from sunflower oil converted into CLA was investigated, and its apparent kinetic model was also established, which can be used as a base for industrial designs.

Preparation of Conjugated Linoleic Acid and Identification of Its Isomers

Conjugated linoleic acid (CLA) is a kind of fatty acid with physiological activities and potential application prospect. A synthesis method of conjugated linoleic acid and a purification technology were studied. CLA was prepared and purified by urea-complexation and conjugation using safflower oil as raw material. The purity of CLA and total recovery of the product was more than 95% and 48%, respectively. The main isomers produced in alkali-catalyzed conjugation were identified by gas chromatography (GC) linked to mass spectrometry (MS) and Fourier transform infrared spectroscopy (FTIR). The total amount of the two main isomers (9cis, 11trons-and 10trans, 12cis-CLA) determined by GC was more than 90% of the product.

Optimization of conjugated linoleic acid triglycerides via enzymatic esterification in no-solvent system

We compared four esterifiable enzymes. The lipase Novozym 435 possessed the highest activity for the conjugated linoleic acid esterification during the synthesis of triglycerides. The triglycerides were synthesized by esterification of glycerol and conjugated linoleic acid （CLA） in a no-solvent system using lipase catalysis. We investigated the effects of temperature, enzyme concentration, water content, and time on esterification. Enzyme and water concentrations of up to 1% of the total reaction volume and a system temperature of 60℃ proved optimal for esterification. Similarly, when the esterification was carried out for 24 h, the reaction ratio improved to 94.11%. The esterification rate of the rotating screen basket remained high （87.28%） when the enzyme was re-used for the 5th time. We evaluated the substrate selectivity of lipase （NOVO 435） and determined that this lipase prefers the 10,12-octadacadienoic acid to the 9,11-octadecadienoic acid.

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

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

Effects of Conjugated Linoleic Acids on Proliferation and Differentiation of Rat Preadipocytes

Conjugated linoleic acids （CLAs） are a generic term for linoleic acid isomers and have a variety of biological functions. After rat preadi- pocytes were incubated in CLAs-supplemented media, their proliferation and differentiation were observed by the cell count and the oil red O stai- ning. The results showed that the CLAs at different concentrations inhibited proliferation of the rat preadipocytes in a time- and dose-dependent manner. And the CLAs greatly decreased intracellular lipid content in mature adipocytes. Moreover, lipogenesis was inhibited by the CLAs in a dose-dependent manner. Therefore, the CLAs inhibit the lipogenesis by reducing the number of preadipocytes and decreasing the intracellular lipid

Increasing Conjugated Linoleic Acid Content in Milk and Cheese after Supplementing a Blend of Crude Soybean Oil Sediment Combined with Fish Oil to Grazing Dairy Cows

The aim of the work was to improve the healthy value of milk and cheese fatty acids (FA) by feeding a mix of crude soybean oil sediment (CSOS) combined with fish oil (FO) to grazing dairy cows. The CSOS is a by-product commonly discarded after oil extraction containing 3.3% moisture, 6% total ash and 70.7% oil, locally available, comparatively economic and easy to mix with other feed ingredients. The experiment lasted 55 days from September 30th to November 23th 2018 and was carried out at the dairy farm “Gacef” provider of milk to the dairy industrial plant “Capilla Del Señor” (CDS) located at the Villa María City, Córdoba Province, Argentine. A herd of 80 multiparous Holstein cows producing 24 kg-1 milk·cow-1·day-1 was used. The cows grazed an alfalfa and an oat pasture that represented about 47% of total dry matter (DM) intake supplemented at 8.5 kg DM·cow-1·day-1 with a total mixed ration (TMR) composed (DM basis) by cracked corn grain (35.18%), whole plant corn silage (31.98%), pelletized soyben meal (17.99%), the CSOS supplement (13.85%) and FO (0.99%). The TMR was supplied by halves after each milking time in groupal feeders yielding 1.4 kg·cow-1·day-1 of the CSOS and 0.1 kg·cow-1·day-1 of FO. Before the start of lipid supplementation, milk samples (5) were obtained from the farm-tank representing the standar or reference milk (Ref-Milk). After 21 days of supplementary lipid supply, additional milk samples (5) were obtained representing the modified milk (Mod-Milk). Milk samples were analyzed for chemical composition and milk FA profile. At each time, sufficient quantities of both (Ref- and Mod-Milk) were collected for manufacturing six types of cheeses. The results were analyzed through the Student-T test for independent observations. Oil supplementation did not modify (P > 0.05) the chemical composition of milk. Concentration of butyric acid (C4:0) in milk was not affected (P < 0.858). Concentration of total saturated FA (SFAs) in Ref-Milk averaged 58.83 g 100 g-1 FA and was decreased to 49.67 g 100 g-1 FA in Mod-Milk (P < 0.0001). Monounsaturated FA (MUFAs) increased (P < 0.001) from 32.03 g 100 g-1 FA in Ref-Milk to 38.13 g 100 g-1 FA in Mod-Milk (+19.07%) whereas polyunsaturated FA (PUFAs) increased (+36.1%) from 4.71 to 6.41 (P < 0.004). The Mod-Milk showed a significant (P < 0.002) reduction (-15.3% or 5.9 g 100 g-1 FA) for the total concentration of the potentially atherogenic fraction of milk FA (C12:0 to C16:0). The atherogenic index (AI) also decreased (P < 0.012) from 1.98 in Ref-Milk to 1.42 in Mod-Milk (-28.4%). Concentration of vaccenic acid (VA, trans-11 C18:1) in Mod-Milk averaged 7.77 g 100 g-1 FA which represented a 162 % increase (P < 0.0001) over that observed in Ref-Milk (2.95 g 100 g-1). Concentration of conjugated linoleic acid (CLA, cis-9, trans-11 C18:2) in Ref-Milk averaged 1.47 g 100 g-1 FA and showed an important increase (P < 0.002) in the Mod-Milk (3.86 g 100 g-1 FA, +163%). The omega 6/3 ratio resulted lower (P < 0.012) in the Ref-Milk (2.28) compared to the Mod-Milk (2.83). Milk and cheese FA composition were highly correlated (R2 = 0.99, P < 0.0001). The Mod-Cheeses showed similar results in AI, total concentration of SFAs, MUFAs and PUFAs compared to the milk of origin. Differences in FA composition between the cheeses made with the Ref- and Mod-Milk were equivalent to those described for milks. It is concluded that supplementation with a blend of CSOS supplement and FO was an effective way to improve the healthy value of dairy products by reducing contents of SFAs, atherogenic FAs and the atherogenicity index with a concomitant increase in VA and CLA. Modifications induced in the Mod-Milk were recovered in the Mod-Cheeses. The results obtained may help to reduce saturated fat intake and fight or prevent incidence of non-communicable, cardiovascular and chronic diseases.

Study on Microwave Preparation of Conjugated Linoleic Acid from Corn Germ Oil

[Objective] The optimal craft of preparing conjugated linoleic acid from corn germ oil by dint of microwave method was studied. [Meth- od] Microwave power, microwave mode of action, the amount of catalyst and solvent were selected for single-factor-experiment. Then, based on the single-factor-experiment, the catalyst and solvent amount, and microwave function time were chosen for orthogonal experiment so as to deter- mine the optimal craft of preparing CLA from corn germ oil. UV absorption spectra and infrared absorption spectrum were used to analyse the struc- tural features of natural corn germ oil and CLA. [Resalt] The optimal preparation condition was as follow： the catalyst was 0.6 times heavier than oil, solvent was 3 times heavier than oil weight, microwave worked for ten minutes. Under the optimal condition, CLA was 56.3% and conversion rate was 99.47 %. The results indicated that non-conjugated double bonds of linoleic acid can be isomerized and changed into conjugated double bonds under the conditions of microwave irradiation,[ Conduslon] The study provided a new way for the preparation of CLA.

Effect of Supplementation of Conjugated Linoleic Acid in Diets on Growth Performance and Total Lactic Bacteria iin Small Intestine of Broiler

The effect of supplementation of conjugated linoleic acid （CLA） in diets on growth performance and total lactic bacteria （LAB） in small intestine of broiler. One hundred sixty eight broilers （Arbor Acres; 1 wk old） were randomly assigned to 8 groups. Each group （male 21 and female 21 broiler chickens） was further randomly divided into 3 replicates of 7 chickens were assigned to 4 dietary treatments （0%, 0.5%, 1.0%, and 1.5% CLA）. Feed consumption and BW were recorded at every 7-day period. On day 56, and each week were collected at ileal content in small intestine for the total count of lactic acid bacteria （LAB）. There were highly significant differences in body weight gain, average dairy feed intake, average dairy gain and feed conversion ratio among the treatments （P 〈 0.01）. Moreover, our results revealed that the highest detection trend from the ileal occurred during the period in the supplementation of CLA.

Effect of cis-9,trans-11-conjugated linoleic acid on cell cycle of gastric adenocarcinoma cell line(SGC-7901)

AIM: To determine the effect of cis -9, trans -11-conjugated linoleic acid (c9, t11-CLA) on the cell cycle of gastric cancer cells (SGC-7901) and its possible mechanism in inhibition cancer growth. METHODS: Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA, cyclin A, B(1), D(1), p16(ink4a) and p21(cip/waf1) of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25, 50, 100 and 200 micromol.L(-1))of c 9, t 11-CLA for 24 and 48h, with a negative control (0.1% ethane). RESULTS: The cell growth and DNA synthesis of SGC-7901 cells were inhibited by c9, t11-CLA.SGC-7901 cells. Eight day after treatment with various concentrations of c9, t11-CLA mentioned above, the inhibition rates were 5.92%, 20.15%, 75.61% and 82.44%, respectively and inhibitory effect of c9, t11-CLA on DNA synthesis (except for 25 micromol.L, 24h) showed significantly less (3)H-TdR incorporation than that in the negative controls (P【0.05 and P【0.01). Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations at various times significantly decreased the expressions of PCNA (the expression rates were 7.2-3.0%, 24h and 9.1-0.9% at 48h, respectively), Cyclin A (11.0-2.3%, 24h and 8.5-0.5%,48h), B(1) (4.8-1.8% at 24h and 5.5-0.6% at 48h)and D(1) (3.6-1.4% at 24h and 3.7%-0 at 48h) as compared with those in the negative controls(the expressions of PCNA, Cyclin A, B(1) and D(1) were 6.5% at 24h and 9.0% at 48h, 4.2% at 24h and 5.1% at 48h, 9.5% at 24h and 6.0% at 48h,respectively)(P【0.01), whereas the expressions of P16(ink4a) and P21(cip/waf1), cyclin-dependent kinases inhibitors(CDKI), were increased. CONCLUSION: The cell growth and proliferation of SGC-7901 cell is inhibited by c9, t11-CLA via blocking the cell cycle, with reduced expressions of cyclin A,B(1) and D(1) and enhanced expressions of CDKI(P16(ink4a) and p21(cip/waf1)).

Production of conjugated linoleic acids by Lactobacillus plantarum strains isolated from naturally fermented Chinese pickles

Naturally fermented pickles harbour many lactic acid bacteria （LAB）. Forty-three LAB strains with conjugated linoleic acid （CLA）-producing ability were isolated from three naturally fermented pickle brines. Of these isolates, Ip15 identified as Lactobacillus plantarum by API 50 CHL system and full-length 16S rDNA sequence analysis exhibited the highest CLA-producing ability （26.1% conversion） at 48 h in de Man Rogosa Sharpe （MRS） broth in the presence of 100 IJg/ml of linoleic acid （LA）. Compared to other strains, L. plantarum strain Ip15 showed the highest tolerance upon increased levels of LA in the medium, i.e., up to 600 μg/ml. This strain converted about 25% of LA into CLA isomers [predominantly cis-9, trans-11 CLA （9-CLA） and trans-lO, cis-12 CLA （10-CLA）], of which 75% was 9-CLA. Interestingly, though the conversion rate of LA into CLA by Ip15 remained stable between 100 to 600μg/ml LA levels in the medium, it dropped sharply at 1000 μg/ml. Taken together, the Ip15 strain displayed relatively high LA tolerance with higher conversion rate, which implies that this strain is a valuable candidate for enhancing the CLA content in food-sources like pickles.

Conjugated linoleic acid isomers and their precursor fatty acids regulate peroxisome proliferator-activated receptor subtypes and major peroxisome proliferator responsive element-bearing target genes in HepG2 cell model

The purpose of this study was to examine the induction profiles （as judged by quantitative reverse tran- scription polymerase chain reaction （qRT-PCR）） of peroxisome proliferator-activated receptor （PPAR） α,β, y subtypes and major PPAR-target genes bearing a functional peroxisome proliferator responsive element （PPRE） in HepG2 cell model upon feeding with cis-9,trans-11-octadecadienoic acid （9-CLA） or trans-10,cis-12-octadecadienoic acid （10-CLA） or their precursor fatty acids （FAs）. HepG2 cells were treated with 100 pmol/L 9-CLA or 10-CLA or their precursor FAs, viz., oleic, linoleic, and trans-11-vaccenic acids against bezafibrate control to evaluate the induc- tion/expression profiles of PPAR （α, β, γ subtypes and major PPAR-target genes bearing a functional PPRE, i.e., fatty acid transporter （FAT）, glucose transporter-2 （GLUT-2）, liver-type FA binding protein （L-FABP）, acyl CoA oxidase-1 （ACOX-1）, and peroxisomal bifunctional enzyme （PBE） with reference to β-actin as house keeping gene. Of the three housekeeping genes （glyceraldehyde 3-phosphate dehydrogenase （GAPDH）, β-actin, and ubiquitin）, β-actin was found to be stable. Dimethyl sulfoxide （DMSO）, the common solubilizer of agonists, showed a significantly higher induction of genes analyzed, qRT-PCR profiles of CLAs and their precursor FAs clearly showed upregulation of FAT, GLUT-2, and L-FABP （-0.5-.0-fold）. Compared to 10-CLA, 9-CLA decreased the induction of the FA metabolizing gene ACOX-1 less than did PBE, while 10-CLA decreased the induction of PBE less than did ACOX-I. Both CLAs and precursor FAs upregulated PPRE-beadng genes, but with comparatively less or marginal activation of PPAR subtypes This indicates that the binding of CLAs and their precursor FAs to PPAR subtypes results in PPAR activation, thereby induction of the target transporter genes coupled with downstream lipid metabolising genes such as ACOX-1 and PBE. To sum up, the expression profiles of these candidate genes showed that CLAs and their precursor FAs are involved in lipid signalling by modulating the PPAR a, 13, or ~ subtype for the indirect activation of the PPAR-target genes, which may in turn be responsible for the supposed health effects of CLA, and that care should be taken while calculating the actual fold induction values of candidate genes with reference to housekeeping gene and DMSO as they may impart false positive results.

Influence of Mg/Al Molar Ratio on the Structures and Properties of Ru-Mg Alx Catalysts for Isomerization Linoleic Acid

With the knowledge on the significant effect of basic site and Ru on the catalytic performance of heterogeneous catalysts in the isomerization of linoleic acid to conjugated linoleic acid,a series of Ru-Mg Alx compounds with different basicity have been prepared by controlling the Mg/Al molar ratio. The results showed the catalysts with different basicity markedly influence the structure,the Ru dispersion,properties and catalytic performances for the isomerization reaction. The strong basic site is conductive to the high yield of CLA products. The strong basic site and the well-dispersion RuO2synergetic catalysis for the isomerization reaction,basic site and the well-dispersion RuO2synergetic effect are possibly via a Mg-O-Ru linkage.

The Effect of Dietary Vegetable Oilseeds Supplement on Fatty Acid Profiles in Milk Fat from Lactating Dairy Cows

To determine the effect of dietary supplementation with vegetable oilseeds on the composition of bovine milk fatty acids （FAs）, 40 Holstein dairy cows were used with a complete randomized design. At the beginning of the experiment, the cows were 150±25 day in milk （DIM）. Total duration of the experiment was six weeks. Measurements were made during the last three weeks. Cows in four treatments were fed with a basal diet （CT） or basal diet supplemented with either whole full fat soybean （WFS）, full fat expanded soybean （FPS） or whole full fat soybean with whole cottonseed and full fat expanded soybean （MIX）. The composition of the milk fat was analyzed by gas chromatography. Relative to control, the conjugated linoleic acid （CLA） concentration in milk fat from cows on FPS was significantly increased by 83.88% （P〈 0.05）. The proportions of C12：0 were decreased by 35.7, 35.51, and 38.65% in milk fat from cows on WFS, MIX, and FPS compared with cows on CT. Similar decreases in C 14：0 were 23.83, 24.85, and 31.48% in WFS, MIX, and FPS treatments, respectively. Feeding vegetable oilseeds increased the proportion of healthy FAs （mainly CLA）, whereas decreased the concentratiofi of C12：0 and C14：0. Therefore, milk and dairy products would have higher nutritive and therapeutic value.

Fatty Acids and Triglycerides Composition in Uruguayan Cow, Sheep and Goat Cheeses

Adverse health consequences are associated with consumption of so-called trans fatty acids （FAs） generated during chemical hydrogenation processes. Naturally-occurring trans fats, including trans vaccenic acid （TVA） derived from a conjugated isomer of linoleic acid （18：2 cis-9, trans-11）, （CLA） in contrast, are recognized as having potentially beneficial effects on human health. These natural trans FAs are found in fat from dairy products and meat of ruminants, and have distinct effects compared with trans FAs industrially produced. The lipid composition of cheeses depends on the milk used. In this work was determined CLA and TVA content in milk fat of sheep and cow to be 1.4% and 3.2%, respectively, and from goat, 0.7% and 1.8%. Also, differences in CLA and TVA content were found in fat extracted from samples of the same cheese type made from cow＇s milk from the same company but with different production dates during a year. The levels of CLA and TVA found in Uruguayan cheeses were generally higher than levels reported in previous studies with comparable cheeses produced in other countries. Milk fat is well-known to confer specific properties to foods. This in turn will affect the rheology and sensory attributes as food. For this reason, it is of interest to determine the triglyceride （TAG） composition in milk-derived foods. Results show that there are characteristic differences in the TAG composition of the different cheeses. We found minimal differences between cheeses from goat and sheep but found distinct characteristics for TAGs from cow milk-derived cheese.

Studies on mechanism of cis9,trans11-CLA and trans10,cis12-CLA inducing apoptosis of human breast cancer cell line MCF-7

Objective： The aim of the study was to explore the activities of cis9, trans11-CLA （C9, t11-CLA） and transl0, cis12-CLA （t10, c12-CLA） inhibiting tumor, and investigate their relationships with PPARy and apoptotic proteins, and mechanism of anti-cancer. Methods： The inhibitory rate, cell growth curve and apoptotic morphological observation of MCF-7 cells were obtained by MTT assay, trypan blue staining and Hoechst33342 fluorescence staining. The apoptotic rate and cell cycle were detected with flow cytometry. Transcriptional level of genes was detected with RT-PCR semi-quantitative method, and Western blot was performed to detect proteins levels. Results： The two CLA isomers could reduce cell proliferation （P 〈 0.05）, increase apoptotic rate （P 〈 0.05）, and increase obviously the transcriptional and protein levels of PPARy （P 〈 0.01）. The synchronism and correlation between the effects of CLA to PPARy and apoptotic proteins Bax, Bcl-2, Caspase 3 changes were found with the dose- and time-dependent manners. There was cooperative relation between the levels of PPARy and the rates of Bax/Bcl-2, Caspase 3 （small fragment） by experiments of PPARy inhibitor GW9662 and ligand Rosiglitazone. Conclusion： The apoptotic pathway of PPARy-Bcl-2-Caspase 3 signaling was found. The C9, t11-CLA and tl0, c12-CLA could inhibit MCF-7 cell proliferation and promote apoptosis via activating PPARy-Bcl-2-Caspase 3 pathway. CLA may be a kind of activator of PPARv.

A Proposed Stereochemical Mechanism for the Improved Preparation of Maleic Anhydride Cycloadduct of CLA

The fatty acid derivatives, prepared from renewable natural oils, can be used as highly promising and potential substitutes for petrochemicals. The study of process improvement and stereochemical mechanism for preparing these derivatives would be beneficial for their industrial production. Conjugated linoleic acid (CLA) containing 9cis-11trans (9c, 11t) and 10trans-12cis (10t, 12c) isomers was prepared from Salicornia herbacea seed oil. Maleic anhydride cycloadduct of CLA (MAC) was prepared by an improved process, and it was characterized by FTIR, 1H and 13C NMR, etc. A new method to calculate conformers-ratio of CLA or MAC was also developed. Furthermore, the stereochemical mechanism for the improved preparation of MAC was proposed primarily by the calculation method above. The following observations were made: 1) The yield of MAC could reach as high as 96.7% under mild reaction conditions and with an easy and efficient product separation;2) The trans-trans CLA in the s-cis conformation acted as a predominant reactant to Diels-Alder [4 + 2] cycloaddition of maleic anhydride, which was the main reaction occurred simultaneously with catalytic configurational isomerizations of CLA in one step;3) From all studied CLA conformers, the most stable conformation was the s-trans conformation of trans-trans CLA, while the s-cis conformation of trans-trans CLA had the most favorable structural parameters for cyclohexenyl ring formation;4) Four MAC conformers derived from 9c, 11t- and 10t, 12c-CLA, were obtained as final main products that were determined to be cis-cycloadducts;5) The endo/exo ratios of the cis- cycloadducts derived from 9c, 11t- and 10t, 12c-CLA, were 2.14:1 and 1.99:1, respectively;and 6) The results obtained from the calculation method above were in excellent accordance with those from our experiments.

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 28 d 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,in vitro experiment was further conducted by treating rumen epithelial cells without or with IL-17A+TNF-αfor 12 h 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.

Influence of yeast on rumen fermentation,growth performance and quality of products in ruminants:A review

This review aims to give an overview of the efficacy of yeast supplementation on growth performance,rumen pH,rumen microbiota,and their relationship to meat and milk quality in ruminants.The practice of feeding high grain diets to ruminants in an effort to increase growth rate and weight gain usually results in excess deposition of saturated fatty acids in animal products and increased incidence of rumen acidosis.The supplementation of yeast at the right dose and viability level could counteract the acidotic effects of these high grain diets in the rumen and positively modify the fatty acid composition of animal products.Yeast exerts its actions by competing with lactate-producing(Streptococcus bovis and Lacto-bacillus)bacteria for available sugar and encouraging the growth of lactate-utilising bacteria(Mega-sphaera elsdenii).M.elsdenii is known to convert lactate into butyrate and propionate leading to a decrease in the accumulation of lactate thereby resulting in higher rumen pH.Interestingly,this creates a conducive environment for the proliferation of vaccenic acid-producing bacteria(Butyrivibrio fibrisolvens)and ciliate protozoa,both of which have been reported to increase the ruminal concentration of trans-11 and cis-9,trans-11-conjugated linoleic acid(CLA)at a pH range between 5.6 and 6.3.The addition of yeast into the diet of ruminants has also been reported to positively modify rumen biohydrogenation pathway to synthesise more of the beneficial biohydrogenation intermediates(trans-11 and cis-9,trans-11).This implies that more dietary sources of linoleic acid,linolenic acid,and oleic acid along with beneficial biohydrogenation intermediates(cis-9,trans-11-CLA,and trans-11)would escape complete bio-hydrogenation in the rumen to be absorbed into milk and meat.However,further studies are required to substantiate our claim.Therefore,techniques like transcriptomics should be employed to identify the mRNA transcript expression levels of genes like stearoyl-CoA desaturase,fatty acid synthase,and elon-gase of very long chain fatty acids 6 in the muscle.Different strains of yeast need to be tested at different doses and viability levels on the fatty acid profile of animal products as well as its vaccenic acid and rumenic acid composition.