Positive Control Treatment Groups Research Articles

Effect of Metformin on Interleukin-6 Expression in Human Fibroblast Cell Aging Model

During skin aging, there is excessive secretion of inflammatory cytokines such as interleukin-6 (IL-6), which can make the ageing process more severe. Metformin has been known to have good anti-inflammatory activity through various pathways, one of which reduces the expression of inflammatory cytokines. This study aimed to analyze the effect of metformin treatment on IL-6 gene expression in an in vitro human fibroblast cell. Human fibroblast cells were obtained through foreskin isolation, and 72 cultured human fibroblast cells were divided into six groups based on cell passages, ranging from the third to the eighth. The expression of IL-6 was assessed in three treatments: negative control (normal cells), metformin 100 µM, and positive control (Vitamin E 50 µM). Treatment and measurement of IL-6 gene expression were carried out using qRT-PCR and calculated using the Livak-Schmittgen method. The results were then compared and analyzed using One-Way Analysis of Variance (ANOVA) and followed by post-hoc analysis. The negative control group had the lowest IL-6 gene expression compared to the metformin group and positive control group. The negative control IL-6 expression showed the highest value at passage 3 (0.166 ± 0.04) and the lowest at passage 6 (0.048 ± 0.04). Meanwhile, the expression of IL-6 positive control passage 4 (5.590 ± 3.34) showed the highest value and passage 7 (0.000 ± 0.00) showed the lowest value. In the metformin group, IL-6 gene expression was highest in passage 5 (0.836 ± 0.15) and lowest in passage 3 (0.078 ± 0.02). Based on treatment, there is a difference in IL-6 gene expression at passage 4 (p-value <0.05) and passage 5 (p-value <0.001). Metformin treatment passage 5 showed a significant difference with negative control (p-value <0.05) and with positive control (p-value <0.05). Our study concluded that the administration of metformin had no effect on IL-6 gene expression in human fibroblasts. However, metformin demonstrated anti-aging potential, as evidenced by a statistically significant difference in IL-6 expression between the negative control and positive control treatment groups.

Evaluation of the Protective and Healing Effects of Heracleum lasiopetalum Boiss on a Modified Acetic Acid-Induced Ulcerative Colitis Model in Rats

Background: Ulcerative colitis (UC), a chronic inflammatory condition of the colon with no definitive cure, necessitates the exploration of innovative therapies. Herbal remedies combined with conventional drugs may offer complementary benefits, enhancing treatment outcomes. Objectives: This study investigates the therapeutic effects of Heracleum lasiopetalum Boiss in a rat model of acetic acid-induced UC. Methods: Forty-eight adult female Wistar rats were randomly allocated to six groups (n = 8 per group) for each of two experiments. UC was induced by intracolonic administration of 1 ml of 4% acetic acid for 10 minutes. In the treatment groups, female rats received an oral gavage of 5%, 10%, and 40% aqueous plant extract, sulfasalazine (100 mg/kg), and distilled water for 6 days, starting 3 days after acetic acid administration. The protective groups received substances via oral gavage from 7 days before to 3 days after acetic acid administration. The extent of mucosal ulcers, hyperemia, inflammation, and mucosal bleeding was evaluated based on the Gerald Classification System Score (Macroscopic). Pathological assessment was conducted on prepared slides using the modified Wallace method (Microscopic). Changes in body and colon weight, along with food and water intake, were examined. Results: Significant changes in food intake were observed in both the extract and positive control treatment groups, exhibiting a notable difference compared to the negative control group (P < 0.05). Body weight changes experienced a significant increase in the positive control treatment group compared to the negative control group (P < 0.05), while no significant difference was evident between the extract and negative control treatment groups (P > 0.05). In terms of water and food intake, as well as weight changes, no significant differences were detected among the various protective groups (P > 0.05). Both microscopic and macroscopic examinations revealed a substantial enhancement in the colon of the extract and positive control treatment groups compared to the negative control group (P < 0.05), with no significant difference observed between the protective groups (P > 0.05). Conclusions: Heracleum lasiopetalum extract demonstrates a dose-dependent reduction in colon hyperemia, mucosal ulceration, inflammation, and fibrosis. This highlights its potential as a supplementary treatment option for UC, emphasizing the need for further investigation.

Effect of nano zinc oxide or chelated zinc as alternatives to medical zinc oxide on growth performance, faecal scores, nutrient digestibility, blood profiles and faecal Escherichia coli and Lactobacillus concentrations in weaned piglets

A total of 144 weaned piglets (6.80 ± 0.46 kg, [Landrace × Yorkshire] × Duroc) were used in a 4-week feeding trial to determine the effect of nano zinc oxide or chelated zinc as alternatives to medical zinc oxide (ZnO) in weaned piglets. The pigs were randomly distributed to one of 6 treatment groups (4 pigs in a pen, 6 replicate pens per treatment). The dietary treatments were negative control (NC), no additional zinc oxide in the diet; positive control (PC), NC + 2500 mg/kg ZnO; 100 mg Chelate (NC + 100 zinc chelate); 200 mg Chelate (NC + 200 mg/kg of zinc chelate); 100 mg Nano (NC + 100 mg/kg ZnO nanoparticles), and 200 mg Nano (NC + 200 mg/kg nanoparticles). The growth performance of pigs fed the PC and Nano diets were significantly higher than that of pigs in the Chelate treatment groups (p < .05). In the overall periods, the faecal scores were significantly increased (p < .05) in the PC treatment group compared to the 100 mg/kg Chelate and Nano treatment groups. The apparent total tract digestibility (ATTD) of crude protein and faecal Lactobacillus concentrations were significantly decreased (p < .05) in the NC group compared to the other groups. The ATTD of zinc was significantly increased (p < .05) in the Chelate treatment groups compared to the other treatment groups. In conclusion, 200 mg/kg Nano showed similar effects on growth performance, nutrient digestibility, and faecal Lactobacillus concentrations in weaning pigs as medical ZnO. HIGHLIGHTS To evaluate the effects of nano zinc oxide or chelated zinc as an alternative to medical zinc oxide in weaned piglets High-dose zinc oxide and 200 mg/kg zinc oxide nanoparticle supplementation showed beneficial effects on growth performance and crude protein digestibility Supplementation with zinc chelated with glycine resulted in significantly higher (p < .01) the ATTD of zinc than other treatments groups. Faecal Lactobacillus concentrations were significantly decreased (p < .05) in the no additional zinc oxide diet group compared to the other treatment groups. Nano-ZnO at 100 or 200 mg/kg had similar effects on growth performance and nutrient digestibility with lower zinc excretion than that of weaned pigs given medical zinc oxide.

Wound Healing Activity of Galam Flower (Melaleuca Cajuputi Subsp. Cumingiana (Turcz.) Barlow) Methanol Extract Wistar Rats

Wound is an incontinence condition of skin or mucosal epithelial tissue due to physical or thermal damage. One of the plants that has the potential as a wound healer is gelam (Melaleuca sp). Gelam flower methanol extract has antibacterial activity with a minimum inhibitory level of 1.7 mg/mL. This study aimed to analyze the wound healing activity of gelam flower methanol extract (Melaleuca sp.) in Wistar strain rats that were initiated by the wound seen from the histology of the rat skin. This research uses posttest only method with control group design. Thirty male wistar rats were divided into five groups consisting of a positive control group, a negative control group, 1% gelam flower extract gel, 2% gelam flower extract gel, and 4% gelam flower extract gel. Based on histological data, the positive control treatment group and 4% gel treatment group gave the same results. Both indicate that the skin tissue has begun to connect. The conclusions the three gelam flower methanol extract gel formulas showed wound healing activity and the 4% gelam flower methanol extract gel (Melaleuca Sp.) gave the greatest wound healing activity.&#x0D; Keyword: Melaleuca sp, antibacterial activity, wound initiated healing

Neuronal cell membrane protective effects of &lt;I&gt;Combretum micranthum&lt;/I&gt; methanol leaf extract on lead-induced brain damage in Swiss albino mice

Combretum micranthum is used traditionally for many therapeutic purposes such as fatigue, liver ailments, headache, convalescence, blood disease, weight loss among others. Studies suggested that free radical production may be one main reason behind stress induces neurochemical changes that include neurotransmitter imbalance and histopathological alterations in the brain cell. Thus this study examined the relationship between brain histopathological alterations and neurotransmitter imbalance (gamma aminobutyric acid - GABA) in lead exposure, and possible neuroprotective role of Combretum micranthum methanol leaf extract in mice. Thirty six (36) Swiss Albino mice (19 - 22g body weight) were used for the study, randomized equally into six groups and treated for the period 14days: a) Normal Control (Distilled water), b) Negative control (40 mg/kg lead acetate), c) lead acetate + 100 mg/kg b.w. extract, d) lead acetate + 50 mg/kg b.w. extract, e) lead acetate + 25 mg/kg b.w. extract and f) positive control (lead acetate + diazepam 0.5 mg/kg b.w). The study assayed for protective potential of Combretum micranthum on neuronal cell membrane through determination of the brain cells malondialdyhyde (MDA) levels, morphology and GABA levels. Result of the study showed a significantly increase level of GABA in the brain of mice administered doses of the extract with a decreased level of MDA, as compared to those mice treated with 40 mg/kg lead acetate alone, which showed decreased level in GABA (310.83pg/ml), but an increased level of MDA (30.03μmolTBARS/mg). Also the mice administered doses of the extract showed normal neurons while intensive neuronal necrosis was observed on those mice treated with 40mg/kg lead acetate alone. However, mice administered with the doses of the extract shows no any significant difference with those in the normal control and positive control treatment groups. Also the Combretum micranthum methanol leaf extract was found, using GC-MS, to contain propargylamine, a compound known to possess anti-apoptosis functions, and also those with GABAergic functions 3,4-dichlorophenylhydrazine, guanidine and aminooxyacetic acid. Findings of the present study has proven Combretum micranthum to be a potential plant in managing and preventing brain structural damage induced by lead administration.&#x0D; Keywords: Lead, Combretum micranthum, GABA, malondialdyhyde (MDA) and histopathology

Effects of Feeding Different Postbiotics Produced by Lactobacillus plantarum on Growth Performance, Carcass Yield, Intestinal Morphology, Gut Microbiota Composition, Immune Status, and Growth Gene Expression in Broilers under Heat Stress.

Simple SummaryHeat stress is a serious issue in commercial broiler production in hot and humid countries, including Malaysia. Exposure of broilers to heat stress affects their health and productivity. In this context, antibiotics are widely used at sub-therapeutic levels as growth promoters to reduce stress and infectious diseases in order to sustain productivity in commercial broiler farms. However, the extensive use of antibiotics as growth promoters for a long time leads to the development of antibiotic-resistant bacteria and the possibility of antibiotic-resistant genes being transferred among organisms. Recently, postbiotics produced by Lactobacillus plantarum have been widely studied as a feed additive in order to replace in-feed antibiotics. However, to date, no studies have investigated the role of postbiotics in feed for broilers under heat stress.The effects of feeding different postbiotics on growth performance, carcass yield, intestinal morphology, gut microbiota, immune status, and growth hormone receptor (GHR) and insulin-like growth factor 1 (IGF-1) gene expression in broilers under heat stress were assessed in this study. A total of 252 one-day-old male broiler chicks (Cobb 500) were randomly assigned in cages in identical environmentally controlled chambers. During the starter period from 1 to 21 days, all the birds were fed the same basal diet. On day 22, the birds were weighed and randomly divided into six treatment groups and exposed to cyclic high temperature at 36 ± 1 °C for 3 h per day from 11:00 to 14:00 until the end of the experiment. From day 22 to 42 (finisher period), an equal number of birds were subjected to one of the following diets: NC (negative control) basal diet; PC (positive control) basal diet + 0.02% oxytetracycline; or AA (ascorbic acid) basal diet + 0.02% ascorbic acid. The other three groups (RI11, RS5 and UL4) were basal diet + 0.3% different postbiotics (produced from different Lactobacillus plantarum strains, and defined as RI11, RS5 and UL4, respectively). The results demonstrated that birds fed RI11 diets had significantly higher final body weight, total weight gain and average daily gain than the birds that received the NC, PC and AA treatments. The feed conversion ratio was significantly higher in the RI11 group compared with the other groups. Carcass parameters were not affected by the postbiotic-supplemented diet. Postbiotic supplementation improved villi height significantly in the duodenum, jejunum and ileum compared to the NC, PC and AA treatments. The crypt depth of the duodenum and ileum was significantly higher in NC group compared to other treatment groups except RI11 in duodenum, and UL4 in ileum was not different with NC groups. The villus height to crypt depth ratio of duodenum and ileum was significantly higher for the postbiotic treatment groups and AA than the PC and NC treatment groups. The postbiotic RI11 group recorded significantly higher caecum total bacteria and Lactobacillus count and lower Salmonella count compared to the NC and PC treatment groups. The Bifidobacterium population in the NC group was significantly lower compared to the other treatment groups. The postbiotic (RI11, RS5 and UL4) and AA treatment groups showed lower Enterobacteriaceae and E. coli counts and caecal pH than the NC and PC treatment groups. The plasma immunoglobulin M (IgM) level was significantly higher in the birds receiving postbiotic RI11 than those receiving other treatments. The plasma immunoglobulin G (IgG) level was higher in the RI11 treatment group than in the NC, AA and RS5 groups. The plasma immunoglobulin A (IgA) level was not affected by postbiotic supplements. The hepatic GHR mRNA expression level was significantly increased in birds fed postbiotics RI11, RS5 and UL4, AA and PC compared to the NC-fed birds. Postbiotic RI11 led to significantly higher hepatic IGF-1 mRNA expression level compared to the NC, PC, and AA treatments. Mortality was numerically lesser in the postbiotic treatment groups, but not significantly different among all the treatments. In conclusion, among the postbiotics applied in the current study as compared with NC, PC and AA, RI11 could be used as a potential alternative antibiotic growth promoter and anti-stress treatment in the poultry industry.

The effect of microbial phytase supplementation of sorghum-canola meal diets with no added inorganic phosphorus on growth performance, apparent total-tract phosphorus, calcium, nitrogen and energy utilization, bone measurements, and serum variables of growing and finishing swine

Two experiments were conducted with growing and finishing swine to determine the effect of phytase supplementation of sorghum-canola meal diets without added inorganic phosphorus (iP) on growth performance, apparent total-tract P, calcium (Ca), nitrogen (N), and energy utilization, bone strength, bone ash, serum Ca and P concentrations, and serum phosphatase activity. For Exp. 1, 42 crossbred barrows in individual metabolism cages were fed a P-deficient diet for 7 d before starting a 28-d experiment at 24.8 kg body weight (BW). Experiment 1 had 7 treatments that were a negative control (NC) diet supplemented with 0, 400, 800, 1200, or 1600 U of Aspergillus niger (AN) phytase/kg, a positive control (PC) diet, and the PC diet supplemented with 1200 U of AN phytase/kg. Fecal and urine collections were made from d 21–26. Blood samples were collected on d 0, 14, and 28. For Exp. 2, 126 growing-finishing crossbred swine with an initial BW of 21.6 kg were group-fed (3 pigs/pen) in 3 phases (grower, early-finisher, and late-finisher). Experiment 2 had 6 treatments that were a NC diet for each phase supplemented with 0, 200, 400, 600, or 800 U of AN phytase/kg and a PC diet. Fecal collections were made from d 49–54. Blood samples were collected on d 35, 63, and 91. For both experiments, 400 U of AN phytase/kg of diet was adequate (P ≤ 0.05) for growth performance compared with the PC treatment groups. For Exp. 1, apparent total-tract P absorption and retention plateaued at 1200 U of AN phytase/kg of diet (P < 0.01), with fecal Ca and P excretion reduced 22.4% and 28.6%, respectively, compared with the PC treatment group. However, pigs fed the PC + 1200 U of AN phytase/kg absorbed and retained more P (g/d, P < 0.01) than any other treatment group. For Exp. 2, apparent total-tract P absorption, bone strength, and bone ash weight plateaued at 600 U of AN phytase/kg of diet (P < 0.01), with fecal P excretion reduced 29.4% compared with the PC treatment group. For both experiments, the AN phytase treatments did not increase Ca, N, or energy absorption (amount/d or % of intake), and had no effect on serum Ca and P concentrations, or the serum activity of alkaline phosphatase, total acid phosphatase, or tartrate-resistant acid phosphatase.

Tang Wang Ming Mu Granule Attenuates Diabetic Retinopathy in Type 2 Diabetes Rats.

Aims: This study aimed to determine the influence of Tang Wang Ming Mu granule (TWMM) on the diabetic retinopathy of diabetic rats.Methods: Male Wistar rats were divided into seven groups: normal control, diabetes model(DM), diabetes with TWMM (3.6, 7.2, and 14.4 g/kg) treatment, the positive control treatment groups of Qi Ming granules and Calcium dobesilate capsules. All rats were treated for 8 weeks. The levels of body weight, fasting blood glucose (FBG) and glycosylated hemoglobin (HbA1c) in blood were measured to evaluate the antihyperglycemic activity of TWMM. Furthermore, malondialdehyde (MDA), intracellular adhesion molecule-1 (ICAM-1) and vascular endothelial growth factor (VEGF) in serum were measured to study effects of TWMM on oxidative stress and inflammatory in DM2 rats. VEGF, JAK/STAT signaling pathway and SOCS3 in retina was detected by immunohistochemistry.Results: TWMM and the positive control drugs Qi Ming and Calcium dobesilate showed a remarkable suppression of retinal neovascularization and amelioration of retinal internal limiting membrane morphology. Moreover, TWMM significantly decreased HbA1c, MDA, ICAM-1, and VEGF levels in serum of diabetic rats. However, Qi Ming granules showed significantly reduced MDA and VEGF levels (P < 0.01, and P < 0.05, respectively), Calcium dobesilate showed significantly reduced MDA and ICAM-1levels (P < 0.01 and P < 0.05, respectively) in serum. All drug- treated DM2 rats showed significantly lower levels of VEGF, JAK2, P-JAK2, STAT3, and P-STAT3 in retina than DM group, while TWMM and Calcium dobesilate significantly increased SOCS3 in retina.Conclusion: Our data suggest that the diabetic retina protective effect of TWMM might be related to antiinflammatory, antioxidative, upregulation of SOCS3 expression, inhibition of the JAK/STAT/VEGF signaling pathway.

Hispathology of Coronary artery of male rat (Ratus Norvegicus) with high fat diet after being given ethanol extract of Indian acalypha (Acalipha indica. L)

This research aims to know the effect of ethanol extract of Indian acalypha (Acalipha indica L) to histopathology of coronary artery of male rat (Ratus norvegicus) with high fat diet. Twenty male rats (Rattus Norvegicus) males aged 3-5 months with mean weight 200 grams were divided into 5 groups and 4 replications. Group 1 (negative control) was only given standard feed and distilled on ad libidum. Four groups (Positive control, Treatment 1, 2 and 3) were made hypercholesterolaemia by administering 1 mL peroral pork oil for 56 days. On day 14, the cholesterol levels were checked. After hypercholesterolaemia, from day 15 to day 56, each group was given ethanol extract of Indian acalypha peroral with a dose of 200 g / kg BW (P1), 400 g / kg BW (P2) and 800 g / kgBW (P3), whereas the positive control groups were not given ethanol extract of Indian acalypha. On day 57, the dying rat was dissected for the removal of the cardiac organ and the making of coronary artery histopathological preparation. Data on histopathologic observation of coronary artery were analyzed by the Kruskal Wallis test, and if there was a significant difference between treatment groups (p &lt;0.05), then it continued with the Mann-Whitney test. The results showed that in infiltration of fat cells and endothelial cells that experienced damage treatment P1, P2, and P3 which were given extracts of Indian acalypha experienced decrease compared to positive control treatment groups. The result of statistical test of fat cells and endothelial cells in the coronary artery that experienced damage showed significant differences between treatment groups (p &lt;0.05), whereas in the statistical test of coronary artery foam cells showed no significant differences between treatment groups (P&gt; 0 , 05). From the research, it can be concluded that ethanol extract of Indian acalypha (Acalipha indica L) can improve histopathology coronary artery of rat fed high fat diet.

Effectiveness of banana leaves extract (Musa paradisiaca L.) for wound healing

Banana leaves (Musa Paradisiaca, L.) has not been widely used in the treatment purpose of this study was to examine the wound healing activity of the gel of banana leaves (Musa paradiasiaca L.) and determine the most effective concentration for wound healing.Target research is to provide natural wound treatment alternatives. The method used is eksperimental.Prosedur research study began with the identification of a banana leaf, banana leaf extraction, formulation of banana leaf extract gel with a concentration of 1%, 5%, 10% and testing to the test animals were harmed .Animal test are grouped into 5 groups the negative control group (base gel), a positive control (bioplacenton), and 3 groups treatment. Measuring of diameter wound on day-1 through day 7. The observation was tested by using ANOVA and Post Hoc Tukey HSD. ANOVA test results showed a significant difference between the mean percentage of wound healing all groups Treatment .The result of Post hoc Tukey HSD at the 95% confidence level showed significant differences in the negative control group when compared to the positive control group and the treatment group gel 5% and 10% .It indicates that the positive control, gel 5% and 10% have a wound healing effect. Positive control group compared with the group treated gel 5% and 10% showed significant differences that the average value of the percentage of wound healing is higher than the positive control treatment group. It means the difference meant that the positive control has better activity. While the group gel 5% when compared with the 10% gel group no significant difference in this case means the group gel 5% with 10% having a comparable effectiveness of wound healing.

Luoyutong Treatment Promotes Functional Recovery and Neuronal Plasticity after Cerebral Ischemia-Reperfusion Injury in Rats.

Luoyutong (LYT) capsule has been used to treat cerebrovascular diseases clinically in China and is now patented and approved by the State Food and Drug Administration. In this retrospective validation study we investigated the ability of LYT to protect against cerebral ischemia-reperfusion injury in rats. Cerebral ischemia-reperfusion injury was induced by middle cerebral artery occlusion followed by reperfusion. Capsule containing LYT (high dose and medium dose) as treatment group and Citicoline Sodium as positive control treatment group were administered daily to rats 30 min after reperfusion. Treatment was continued for either 3 days or 14 days. A saline solution was administered to control animals. Behavior tests were performed after 3 and 14 days of treatment. Our findings revealed that LYT treatment improved the neurological outcome, decreased cerebral infarction volume, and reduced apoptosis. Additionally, LYT improved neural plasticity, as the expression of synaptophysin, microtubule associated protein, and myelin basic protein was upregulated by LYT treatment, while neurofilament 200 expression was reduced. Moreover, levels of brain derived neurotrophic factor and basic fibroblast growth factor were increased. Our results suggest that LYT treatment may protect against ischemic injury and improve neural plasticity.

Bacteriocins Reduce Campylobacter Colonization and Alter Gut Morphology in Turkey Poults ,

Campylobacter is a leading cause of foodborne illness in the United States. Recent evidence has demonstrated that bacteriocins produced by Bacillus circulans and Paenibacillus polymyxa reduce cecal Campylobacter colonization in broiler chickens infected with Campylobacter jejuni. As Campylobacter coli is the most prevalent Campylobacter isolate recovered in turkeys, the objectives of the present study were to evaluate the efficacy of these bacteriocins against C. coli colonization and their influence on the gastrointestinal architecture of young turkeys. In 3 separate trials, a total of 135 day-of-hatch poults (n = 45/trial) were orally challenged on d 3 with approximately 106 cfu of a mixture of 3 C. coli isolates. Immediately before bacteriocin treatment (d 10), cecal Campylobacter concentrations averaged 1.1 × 107 cfu/ g of cecal contents (n = 15/trial). On d 10 to 12 posthatch, 2 bacteriocin treatment groups were given free access to feed supplemented with purified, microencapsulated bacteriocins, whereas the positive control treatment group had access to untreated feed (n = 10/treatment group per trial). At the end of the 3-d dosing period, ceca and duodenal loops were collected for analysis. In each of the 3 separate trials, treatment with bacteriocin eliminated detectable ceca Campylobacter concentrations (detection limit, 1 × 102 cfu/g of cecal contents) vs. controls (1.0 × 106 cfu of Campylobacter/g of cecal contents). Duodenum crypt depth and goblet cell numbers were also reduced in turkeys treated with either bacteriocin vs. controls (P < 0.05). The dynamic reduction in crypt depth and goblet cell density in turkeys dosed with bacteriocin may provide clues to how bacteriocins inhibit enteric Campylobacter.

Use of conjugated linoleic acid (CLA) enrichments to examine the effects of trans-8, cis-10 CLA, and cis-11, trans-13 CLA on milk-fat synthesis.

Conjugated linoleic acid (CLA) supplements have typically been comprised of 4 isomers (trans-8, cis-10; cis-9, trans-11; trans-10, cis-12; and cis-11, trans-13 CLA). Abomasal infusion of pure isomers has shown that trans-10, cis-12 CLA is a potent inhibitor of milk-fat synthesis, whereas cis-9, trans-11 CLA has no effect. However, there appear to be additional fatty acids that inhibit milk-fat synthesis, and the objective of this study was to investigate the effects of additional CLA isomers present in CLA supplements. Four rumen fistulated Holstein cows (141+/-8 DIM, mean+/-SE) were randomly assigned in a 4 x 4 Latin square experiment. Treatments were abomasal infusion of (1) skim milk (negative control), (2) trans-10, cis-12 CLA supplement (positive control), (3) trans-8, cis-10 CLA supplement, and (4) cis-11, trans-13 CLA supplement. Treatments 2 through 4 were targeted to provide 4 g/d of the CLA isomer of interest. The trans-8, cis-10 CLA supplement had no effect on milk-fat yield, whereas the trans-10, cis-12 CLA supplement reduced milk-fat yield by 35%. The cis-11, trans-13 CLA supplement contained some trans-10, cis-12 CLA, and when data were compared to the positive control treatment group, it was obvious that cis-11, trans-13 CLA also had no effect on milk-fat synthesis. Milk-fat content of specific CLA isomers was significantly elevated within respective treatment groups. Milk yield, DMI, and milk protein yield were unaffected by treatment. Overall, trans-10, cis-12 CLA reduced milk-fat synthesis, whereas the other major isomers present in CLA supplements (trans-8, cis-10 CLA and cis-11, trans-13 CLA) had no effect.