Citric Acid Group Research Articles

Expression of Genes Related to Glycolysis in the Liver and Skeletal Muscle of Rats after Citric Acid Administration

Citric acid is known to alleviate physical fatigue and improve athletic performance; however, the underlying mechanism is unknown. Therefore, we aimed to investigate the effect of citric acid administration on the expression of key glycolysis-related genes in the liver and skeletal muscle of rats. Eight-week-old male Sprague-Dawley rats were divided into two groups—control and citric acid groups. The rats were fasted overnight, after which distilled water or citric acid solution was administered intragastrically; after 150 min, the rats were sacrificed, and the liver and skeletal muscle were collected. In the skeletal muscle, namely soleus and gastrocnemius muscles, the phosphofructokinase and pyruvate kinase gene expression were significantly decreased by citric acid administration. In contrast, the glucokinase and pyruvate kinase gene expression in the liver was significantly increased. These results suggest that exogenous dietary citric acid suppresses glycolysis in the skeletal muscle at the transcription level.

The Evaluation of Dentin Microhardness After Use of 17% EDTA, 17% EGTA, 10% Citric Acid, MTAD Used as Chelating Agents Combined With 2.5% Sodium Hypochlorite After Rotary Instrumentation: An In Vitro SEM Study.

Introduction:The smear layer removed during root canal instrumentation enables penetration of irrigant solution and adhesion of root canal sealants providing a fluid tight seal of obturated root canals, necessitating its removal. The aim of the study was to compare the effect of smear layer removal by 17% Ethylene diamine tetraacetic acid (EDTA), 17% Ethylene glycol tetraacetic acid (EGTA),10% Citric acid and (MTAD solution) a Mixture of tetracycline isomer, an acid and a detergent applied as final rinse , when used along with 2.5% (NaOCl) Sodium hypochlorite and its effect on dentin microhardness.Materials and Methods:Sixty single-rooted human mandibular premolars with minimum curvature (<5°) were instrumented using rotary instrumentation till apical enlargement size 35 RaCe file 0.04 taper. During instrumentation, the canals were irrigated with 2-mL 2.5% NaOCl. After instrumentation, teeth were rinsed with distilled water and were divided into 5 groups (n = 12) according to final rinse for 1 min with 5-mL 17% EDTA followed by 5-mL 2.5% NaOCl (group 1, control group), 17% EGTA (group 2), MTAD solution (group 3), 10% citric acid (group 4), and 17% EDTA (group 5). Teeth were split through the groove prepared, and one-half of specimen were evaluated for smear layer removal using scanning electron microscopy. A score system was followed to evaluate the images and comparisons among groups were performed using Kruskal–Wallis one-way analysis. Multiple comparisons were performed using Mann–Whitney U test. The other half was evaluated for dentin microhardness using Vickers microhardness testing machine. Microhardness values were statistically analyzed using parametric one-way analysis of variance test.Conclusion:Irrigation regimen following the use of 2.5% NaOCl during instrumentation followed by application of 5-mL 17% EDTA solution for 1 min resulted in efficient smear layer removal and less decrease in dentin microhardness compared with 17% EGTA, 10% citric acid, and MTAD solution.

Effect of Final Irrigation Protocol on Dentin Microhardness

Endodontic therapy is essentially a debridement procedure that requires the removal of the irritants of the canal and periapical tissue if success is to be gained. The debridement may include instrumentation of the canal, placement of medicament and irrigants. Complete cleaning of the root-canal system requires the use of irrigants that dissolve organic and inorganic material. The study aimed to evaluate changes in dentin microhardness after canal irrigation with different solutions. Twenty four freshly extracted human mandibular molars (distal roots with single canals) were used. 10mm root length was taken as standard length. The roots were embedded into auto polymerizing acrylic resin using plastic molds before the canals preparation and micro hardness test. The distal roots were prepared with one shape rotary file. Before the preparation each root was irrigated with 1ml distilled water. Then the roots were divided into four groups according to the final irrigation protocol: Group A: NaOCl 2.5%, Group B: EDTA 17%, Group C: Citric Acid 40%, Group D: Distilled Water. For (Vicker microhardness test) the same load and time 500 g test load for 20 seconds, will be conducted three times at distance 0.5mm from canal lumen ; thus there will be 9 indentations on each specimen surface. An average of the three readings for each test condition will be recorded as the VHN value of a specimen. Comparing all four groups statistically there was no significant difference among them. The mean values were found more reduced in EDTA group followed by NaOCL group, and then Control and Citric Acid groups. All the groups showed reduction in dentin microhardness. EDTA group showed the maximum reduction followed by NaOCL group, and least with Citric Acid group.

Citric acid reduces oral biofilm and influences the electrochemical behavior of titanium: Anin situandin vitrostudy

Citric acid (CA) has been suggested as an effective antimicrobial agent against biofilms formed on titanium. However, the antimicrobial effect of CA in biofilms formed in the oral environment and its effects on the physical properties of titanium surface remain unknown. Therefore, this study evaluated the antimicrobial effect of CA on in situ biofilm, whether this treatment favors the bacteria recolonization and its effect on the electrochemical properties of titanium. In the in situ test, volunteers wore a palatal appliance containing titanium discs. After 7 days, the discs (N=21) were exposed in vitro to the following treatments: immersion in 0.9% sodium chloride (control); 40% CA immersion; and 40% CA rubbing. Afterwards, these discs (N=18) were exposed in vitro to new bacterial adhesion with Streptococcus sanguinis. New discs (N=18) without biofilm were exposed to the treatments and subjected to electrochemical tests and surface characterization. Data were analyzed by one-way ANOVA followed by Tukey's HSD test. The CA groups showed a significant reduction (≈ 5-log reduction) in the biofilm formed in situ compared with the control group (p<0.05), but no difference was found between CA application methods (p=0.680). The acid treatment did not favor the recolonization of bacteria (p=0.629). CA treatment did not influence the polarization resistance and capacitance of the oxide film, but statistically enhanced the electrochemical stability of titanium. Citric acid appears to be an effective clinical alternative for treatment of the main etiologic factor in dental implant failure, biofilm formation, enhancing electrochemical behavior of titanium.

Effect of chemical modification with citric acid on the physicochemical properties and resistant starch formation in different starches

Potato, cassava, sweet potato, banana and lentil starches were modified with citric acid (CA) with the main objective of enhancing the resistant starch (RS) and slowly digestible starch (SDS) fractions and to compare starches of diverse botanical origins. The percentage CA substitution of modified starches ranged from 3.84 to 15.06 and showed similar type of XRD patterns, but with variation in intensity and percentage crystallinity. The peaks around 1705 cm−1 and 1150 cm−1 in FT-IR spectra of modified starches confirmed the presence of CA group. Scanning electron microscopy confirmed that there were no noticeable changes in granular structure and morphology. No peaks could be observed in RVA pasting profiles of modified starches, confirming cross-linking reaction. The SDS and RS were significantly higher in modified starches of all origins and consequently there was a lower estimated glyceamic index (EGI). Modified starches were associated with lower setback viscosity indicating their lower temperature stability.

Effect of chitosan on sealer penetration into the dentinal tubules.

The objective of this study is to compare the effectiveness of final irrigation with chitosan, ethylenediaminetetraacetic acid (EDTA), and citric acid (CA) on a resin-based sealer (AH plus sealer [Dentsply DeTrey, Konstanz, Germany]) penetration into dentinal tubules using confocal laser scanning microscopy. Seventy recently extracted human mandibular premolars were instrumented and irrigated with sodium hypochlorite (NaOCl), then divided into four groups according to the final irrigation regimen used: (1) the EDTA group: 17% EDTA + 2.5% NaOCl, (2) the CA group: 10% CA + 2.5% NaOCl, (3) the chitosan group: 0.2% chitosan + 2.5% NaOCl, and (4) the control group: 2.5% NaOCl. All teeth were obturated using the cold lateral condensation technique with gutta-percha and AH Plus sealer labeled with fluorescent dye. The apical 2 mm of specimen was discarded, and slices were obtained for apical, middle, and coronal thirds of the root with 1 mm intervals. Maximum, mean, and percentage of sealer penetration (SP) inside tubules were measured using confocal laser scanning microscopy. The percentage of SP was significantly higher in chitosan, EDTA, and CA group than control group for coronal thirds (P < 0.05), whereas there was no significant difference among all groups for middle and apical thirds. Chitosan and EDTA showed increased mean values of SP depth for middle thirds (P < 0.05). In all sections, the maximum depth of SP was significantly lower in EDTA group than other groups (P < 0.05). Chitosan, EDTA, and CA significantly improved the percentage of SP for coronal thirds.

Preparation and characterization of thermally crosslinked poly(vinyl alcohol)/feather keratin nanofiber scaffolds

Electrospun keratin nanofiber fabricated with non-toxic solvents and crosslinking reagents are promising scaffolds for tissue engineering applications. Keratin from chicken feathers was solubilized in aqueous alkaline conditions and electrospun using aqueous poly(vinyl alcohol)(PVA)/citric acid solution as electrospinning polymer aid. Keratin/PVA nanofibers were successfully prepared containing 10, 20 and 30% keratin to PVA mass ratio. The increase in keratin concentration from 0 to 20% resulted in decreased viscosity of keratin/PVA solutions leading to a reduction in the fiber diameter from 565nm in to 274nm. Further decrease in viscosity with 30% keratin resulted in beads-on-fiber type of morphology. Nanofibers were thermally cross-linked through esterification reaction between carbonyl groups in citric acid and hydroxyl groups in PVA. Cross-linked nanofibers maintained their morphology and pore structure after soaking in water. The incorporation of keratin in PVA nanofiber was confirmed by FTIR and XPS results. Proliferation of fibroblasts after 14days was higher in scaffolds containing 20% keratin which was attributed to the superior biological properties of keratin and higher surface area to volume ratio compared to 30% keratin/PVA scaffolds. Safer extraction, electrospinning and crosslinking conditions of keratin/PVA nanofiber are important for potential uses in tissue engineering.

Folate-conjugated and pH-responsive polymeric micelles for target-cell-specific anticancer drug delivery.

Negatively charged nano-carriers prolonged anti-cancer drugs' blood circulation. However it is difficult to be internalised. Therefore, a negative-to-positive charged micelle surface could improve selectivity for tumour cells and increase uptake chance. In this study, we developed a folate (FA)-conjugated and pH-responsive active targeting micellar system for anti-cancer drug delivery. The FA receptor-mediated active targeting and electrostatic interaction between micelles and cell membrane due to a negative-to-positive charge reversal was combined in one micellar anti-cancer drug delivery system to enhance the tumour targeting and cellular internalisation of micelles. In vitro and in vivo anti-cancer studies demonstrated that the doxorubicin-loaded, FA-conjugated and pH-responsive polymeric micelles possess an enhanced and effective cancer efficiency.

Effect of acidic agents on the wear behavior of a polymer infiltrated ceramic network (PICN) material

Polymer infiltrated ceramic network (PICN) materials exhibit desirable properties for replacement of tooth structure. However, their durability and their integrity in various oral environments, remain relatively unknown. The primary objective of this study is to investigate the effect of acidic agents on the wear behavior of PICNs. Twenty specimens were randomly assigned to four groups and then immersed in either deionized water (control) or acidic agents (2% acetic acid, citric acid or lactic acid solutions) at 37℃ for 4 weeks. Changes in the surface microhardness (SMH) and roughness were measured. Reciprocating wear tests were performed under artificial saliva to 10,000 cycles, and the coefficient of friction (COF) and wear depth were quantified to assess the wear behavior. Scanning electron microscopy (SEM) was used to analyze the wear morphology. Acid erosion decreased the SMH and increased surface roughness of the PICN, especially in lactic acid solution. For less than 2800 cycles, the acetic acid and citric acid groups showed higher COF and wear depths due to combined ceramic and polymer wear; the lactic acid group showed smaller COF and wear depth, due to a wear debris layer that acted as solid lubricant. Beyond 2800 cycles, all four groups exhibited similar COF values, as well as wear depth and wear morphology. Overall, acid erosion had a significant effect on the surface wear history of the PICN, but no effect on its long-term wear properties. Overall, the depth of acidic degradation of the PICN was rather limited.

Spray-dried chitosan/acid/NaCl microparticles enhance saltiness perception

The composition, physicochemical properties and salinity of spray-dried chitosan/acid/NaCl microparticles were tested to ensure a low-sodium and high-salinity salty agent. The spray-dried chitosan/acid/NaCl microparticles were hollow and had a favourable hygroscopicity, and increased NaCl content and decreased organic acid content. Their size of the microparticles was 15.4–32.0μm and increased with NaCl concentration. The microparticles of acetic and lactic acid groups had a NaCl crystal size of 1–2 and 1–4μm, respectively. The NaCl crystals of acetic, lactic and citric acid group microparticles were distributed on the microparticle matrices, mostly on the microparticle surface and mainly on the inner walls of the microparticles walls, respectively. The acetic and lactic acid group microparticles were relatively smaller than general salt, with NaCl crystals distributed on the particle surfaces. Consequently, they were perceived as saltier than general salt and could potentially be regarded as a low-sodium salt for surface-salted foods.

Decontamination of Anodized Implant Surface With Different Modalities for Peri-Implantitis Treatment: Lasers and Mechanical Debridement With Citric Acid.

Although oral rehabilitation with dental implants is a very promising and effective procedure, peri-implantitis is an emerging concern. Surgical and non-surgical methods have been applied to treat peri-implantitis together with various implant surface decontamination methods. However, there is no consensus concerning the most effective treatment for peri-implantitis. The aim of the present study is to evaluate the effects of erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser, photodynamic therapy (PDT), and titanium bur with and without citric acid on ligature-induced peri-implantitis around an anodized implant surface. Thirty dental implants with anodized surface (3.3 × 10 mm) were installed in the mandibles of five beagle dogs. After 3 months, peri-implantitis was induced by applying cotton ligatures subgingivally. After ligature removal (baseline), the implants were divided into the following treatment groups: 1) Er:YAG laser, 2) PDT, 3) titanium bur alone, and 4) titanium bur with citric acid. Animals were sacrificed after 3 months, and clinical, radiologic, histologic, and histomorphometric evaluations were conducted for all treatment modalities. The data were analyzed using one-way analysis of variance and Tukey test. A value of P <0.05 was considered statistically significant. The titanium bur with citric acid group exhibited statistically significantly greater improvement in vertical bone height than the Er:YAG laser group and significantly better bone-to-implant contact than the PDT group and the bur-alone group. Within the limits of the study, the combination of mechanical and chemical treatment proved to be the most effective treatment for disinfection of the anodized implant surface.

Airway remodeling associated with cough hypersensitivity as a consequence of persistent cough: An experimental study.

Chronic cough involves airway remodeling associated with cough reflex hypersensitivity. Whether cough itself induces these features remains unknown. Guinea pigs were assigned to receive treatment with citric acid (CA), saline (SA), or CA+dextromethorphan (DEX). All animals were exposed to 0.5M CA on days 1 and 22. On days 4-20, the CA and CA+DEX groups were exposed to CA, and the SA group to saline thrice weekly, during which the CA+DEX group was administered DEX pretreatment to inhibit cough. The number of coughs was counted during each 10-min CA or SA exposure. Terbutaline premedication was started to prevent bronchoconstriction. Bronchoalveolar lavage and pathology were examined on day 25. Average cough number for 10 CA exposures was examined as "cough index" in the CA group, which was divided into frequent (cough index>5) and infrequent (<5) cough subgroups for lavage and pathology analysis. The number of coughs significantly increased in the CA group from day 13 onwards. In the CA+DEX and SA groups, the number of coughs did not differ between days 1 and 22, while average number of coughs during days 4-20 was significantly lower than at days 1 and 22. Bronchoalveolar cell profiles were similar among the four groups. The smooth muscle area of small airways was significantly greater in the frequent-cough subgroup than in the other groups (in which it was similar), and highly correlated with cough index in CA group. Repeated cough induces airway smooth muscle remodeling associated with cough reflex hypersensitivity.

Effect of manual dynamic activation with citric acid solutions in smear layer removal: A scanning electron microscopic evaluation

Background/purposeChelating agents have been used for the removal of the smear layer on teeth. However, due to inadequate volume and/or penetration of the solutions during irrigation, smear layer removal is less effective in the apical third. The purpose of this study was to compare the efficacy of three chelating solutions with and without manual dynamic irrigation in smear layer removal. Materials and methodsSixty-six single-root canal teeth were decoronated, instrumented, and divided into six experimental groups (n = 10) and two control groups (n = 3). The groups received a final rinse with 1 mL of 17% EDTA and 5% or 10% citric acid (CA) for 1 minute, with or without manual dynamic activation, followed by a final 3-mL rinse with 4.2% NaOCl (5 minutes). The teeth were then longitudinally split and prepared for environmental scanning electron microscopy analysis. Digital images (500×) were taken for smear layer removal evaluation at 2 mm, 6 mm, and 10 mm from the working length. ResultsThe most effective smear layer removal occurred with 5% and 10% CA combined with manual dynamic activation (Groups 7 and 8), where significant differences were observed when compared with the EDTA groups (Groups 2 and 6; P < 0.05). We found no significant differences between manual dynamic activation with 5% and 10% CA (Groups 7 and 8) in smear layer or debris removal (P > 0.05). ConclusionManual dynamic activation of CA improves smear layer removal, and a reduction in CA concentration to 5% does not compromise smear layer removal in comparison with higher concentrations.

Effect of citric acid, herbal feed additive and their combination on the performance of broiler

The experiment was conducted with 108 day old straight-run Hubbard Classic broiler chicks for a period of 35 days to investigate the effects of citric acid, commercial herbal additive (Keqinling) and their combination on growth and carcass traits of broiler. The dietary treatments were control (T0), 0.5% citric acid (T1), 0.2% Keqinling (T2) and combination of 0.5% citric acid +0.2% Keqinling (T3). Final live weight was 1615, 1710, 1707 and 1795g in control, 0.5% citric acid, 0.2% Keqinling and their combination groups respectively. The highest live weight gain (1748g) was found in combination group followed by 0.5% citric acid (1664g), 0.2% Keqinling (1660g), and the lowest (1568g)in control group. The highest feed consumption and feed conversion efficiency was observed in T3 and the lowest in group T0. Significantly (p&lt;0.05) the highest dressed yield (%) was found in 0.5% citric acid group (56.65) than combination (55.73) and Keqinling (55.18) and lowest in control group (54.59). Citric acid reduced the pH of the both feed and faces. The cost of production (Tk/kg broiler) was lowest in citric acid group (Tk. 76.22). Net profit per broiler production was found in 0.5% citric acid group (Tk. 10.03/broiler) followed by combination (Tk. 9.28), Keqinling (Tk. 7.31) and control group (Tk. 6.98) respectively. The addition of 0.5% citric acid and 0.2% Keqinling individually or their combination increase the performance of broiler but citric acid showed better response than Keqinling.Bang. J. Anim. Sci. 2015. 44 (3):143-150

Influence of Citric Acid on the Pink Color and Characteristics of Sous Vide Processed Chicken Breasts During Chill Storage.

Chicken breast dipped with citric acid (CA) was treated by sous vide processing and stored in a refrigerated state for 0, 3, 6, 9, and 14 d. A non-dipped control group (CON) and three groups dipped in different concentrations of citric acid concentration were analyzed (0.5%, 0.5CIT; 2.0%, 2CIT and 5.0%, 5CIT; w/v). Cooking yield and moisture content increased due to the citric acid. While the redness of the juice and meat in all groups showed significant increase during storage, the redness of the citric acid groups was reduced compared to the control group (p<0.05). The percentage of myoglobin denaturation (PMD) of the CA groups was also increased according to the level of CA during storage. Total aerobic counts, Enterobacteriaceae counts, volatile basic nitrogen and thiobarbituric acid reactive substances (TBARS) were generally lower in the citric acid-treated samples than in untreated ones, indicating extended shelf life of the cooked chicken breast dipped in citric acid solution. The shear force of the 2CIT and 5CIT groups was significantly lower (p<0.05). The findings indicated positive effects in the physicochemical properties and storage ability of sous vide chicken breast at 2% and 5% citric acid concentrations.

Fatigue Alleviation Mechanism of Citric Acid Determined by Gene Expression Analysis in the Mouse Liver

Citric acid has been recognized for its ability to alleviate fatigue; however, the mechanism contributing to this effect has not yet been elucidated. Our previous study suggested that the alleviation of fatigue by citric acid intake might be induced by the acceleration of gluconeogenesis. In this study, we tested this hypothesis and evaluated whether the intake of citric acid accelerates gluconeogenesis in the mouse liver through microarray analysis. Because the microarray of focus includes 200 metabolic genes, it could be used to provide information on genes related to glucose metabolism as well as other pathways such as inflammation. Eight-week-old male C57/BL6J mice were divided into the distilled water and citric acid groups (n = 6), and were administered distilled water or a citric acid solution (20 mg/30g body weight) intragastrically with a probe, respectively. Forty minutes after administration, the mice were sacrificed by decapitation. The blood glucose level of the citric acid group was significantly higher (P = 0.001) than that of the distilled water group. The expression levels of genes related to glucose metabolism (Gck, Pfkl, Pklr, Pck1, G6pc) were not changed by the intake of citric acid. On the other hand, some transcriptional differences were observed in several other genes, including those related to inflammation, blood pressure, the electron transport system, uncoupling proteins, and anti-oxidation. The expression levels of genes related to inflammation were reduced in the citric acid group; e.g., the Il6 expression level was 0.78 times lower in the citric acid group than that in the distilled water group. In conclusion, the results of this study suggest that citric acid intake could accelerate gluconeogenesis and suppresses inflammation. Therefore, the fatigue-alleviation effects of citric acid might be induced by an additive effect between the maintenance of blood glucose levels and the suppression of inflammation.

An in vitro scanning electron microscope study to evaluate the efficacy of various root conditioning agents.

Aim:The purpose of present study was to investigate the scanning electron microscopic alterations produced on scaled and root planed dentin surfaces after application of different etching modalities namely citric acid, tetracycline hydrochloride and ethylenediaminetetraacetic acid (EDTA).Materials and Methods:Eighty specimens of teeth were collected and categorized into four groups. In group 1, control group specimens were treated with normal saline for 3 min, group 2 specimens were treated with citric acid, group 3 specimens were treated with tetracycline hydrochloride for 3 min and group 4 specimens were treated with 15% EDTA.Results:Opening of dentinal tubules was seen in all specimens except for control group that was treated with normal saline. The total number of tubules seen was highest in citric acid group as compared to tetracycline hydrochloride and EDTA Group. The total number of patent tubule opening was highest in citric acid as compared to EDTA and tetracycline. The diameter of patent dentinal tubules in citric acid group was more than EDTA and tetracycline.Conclusion:The study showed that all the three agents were effective in removing the smear layer however number of patent and wider diameter dentinal tubules was seen in vitro best in citric acid than EDTA and then in tetracycline hydrochloride. Hence, citric acid group is more efficient than EDTA and tetracycline HCl group in removing the smear layer and in opening of number of patent dentinal tubules.

Comparative analysis of acetic and citric acid on internal milieu of broiler chickens

The aim of the present study was to analyse the effect of two organic acids (acetic and citric acid) inclusion on serum parameters and the level of antioxidant status of broiler chickens. Some organic acidifiers reduce the growth of many intestinal bacteria, reduce intestinal colonisation and reduce infectious processes, decrease inflammatory processes at the intestinal mucosa, increase villus height and function of secretion, digestion and absorption of nutrients. Broiler chickens hybrid Ross 308 (n=180) were divided into 3 groups: one control (C) and two experimental groups (E1, E2). Experimental animals received acetic and citric acid per os in water in single dose 0.25% for 42 days. After 42 days of feeding blood samples were collected (n=10 in each group). Significant decrease of serum triglycerides in citric acid group when compared with the control group was recorded. Acetic acid administration resulted in increased sodium level. Significant increase of albumin content in both experimental groups and increase of bilirubin content in citric group was recorded. Acids administration had no significant effect on other serum and antioxidant parameters. Acetic and citric acid had no harmful influenced on internal milieu of broiler chickens. The research on the field of organic acid will be worthy of further investigation.

The improvement of growth, digestive enzyme activity and disease resistance of white shrimp by the dietary citric acid

A 45-day feeding trial was conducted to evaluate the effects of dietary citric acid on growth, digestive enzyme and disease resistance of white shrimp, Litopenaeus vannamei. Shrimp with initial body weight of 5.57 ± 0.21 g were fed with basal diet supplemented with 0.0 g kg−1 (control), 1.0, 2.0, 3.0, 4.0 and 5.0 g kg−1 citric acid. Results showed that weight gain was increased by 15.9 % and feed conversion ratio was decreased by 0.17 by 2.0 g kg−1 dietary citric acid compared with control group (P 0.05). The activities of serum phenoloxidase, superoxide dismutase and lysozyme in 2.0 and 3.0 g kg−1 citric acid group were significantly higher, and accumulative mortalities of the two groups on the fourth day after injection of Vibrio alginolyticus were significantly lower than those of control group (P < 0.05). Results above demonstrated that dietary citric acid could improve growth performance, immunity and resistance against V. alginolyticus. The supplementation level of citric acid in diet was suggested to be 2.0–3.0 g kg−1 for white shrimp.

Evaluation of smear layer removal from ultrasonically prepared retrocavities by three agents.

Objectives:To evaluate the efficacy of 35% orthophosphoric acid, 24% ethylenediaminetetraacetic acid (EDTA) and 10% citric acid in the removal of smear layer from retrocavities prepared with ultrasonic retro-tips using scanning electron microscopy.Materials and Methods:Root canals of fifty single-rooted teeth were cleaned, shaped, and obturated with gutta-percha and AH plus sealer. The apical 3 mm of each root was sectioned with a diamond disc and retrograde cavities were prepared with Kis # 1 ultrasonic retro-tips to a depth of 3 mm. Retro cavities in Group I were treated with a gel of 35% orthophosphoric acid for 15 seconds, Group II were treated with a gel of 24% EDTA at neutral pH for 2 minutes, and Group III were treated with a gel of 10% citric acid for 2 minutes, followed by 1 minute rinsing with distilled water for all groups. The samples were prepared for scanning electron microscopic observation. Scoring was performed for the presence of the smear layer on the walls of the retrocavity.Results:In the orthophosphoric acid group, it was observed that all dentinal tubules were open in 70% of the samples. The majority of analyzed samples in EDTA and citric acid group showed dentinal tubules covered with the smear layer.Conclusions:Application of 35% orthophosphoric acid gel for 15 seconds on retrocavities prepared with ultrasonic retro-tips is the most effective means for removal of smear layer.