جستجوی مقالات مرتبط با کلیدواژه "اسید سیتریک" در نشریات گروه "دامپزشکی"

Among the various fungal strains screened for citric acid production, Aspergillus niger is known to produce considerable amounts of citric acid and other organic acids when cultivated in submerge fermentation. In this study, optimization of the medium components was carried out using "one-factor-at-a-time" and response surface methods (RSM). One-factor-at-a-time indicated that the amount of citric acid production was increased along with the increasing of agitation speed (from 150 to 200 rpm), raising the incubation temperature (from 17 to 32) and decreasing pH value (to 2). Moreover, in comparison with the other groups, citric acid production in the treatment containing soy bean powder and minerals revealed a significant increase (up to 25 g/l). The results showed that application of ultrasonic wave during the growth phase could remarkably enhance the production of citric acid. Based on the results of one-factor-at-a-time, sucrose and soy bean powder were the selected additives to test their effect on citric acid production using RSM. The two variables were identified to have significant effects on citric acid production and the maximum citric acid production of 58 g/l was resulted from the combination of 230.87 g/l sucrose and 200.81 g/l soy bean powder. In this study, the significant increase in the production of citric acid in the optimal conditions indicated the using of appropriate statistical methods and also the correct levels of selected variables.

Effect of citric, acetic and propionic acid's spray, on some microbial, chemical andorganoleptic properties of packaged fresh chilled beef was studied. Chuck portion of bullsmeat was treated with 1% sterile solutions of each of citric, acetic and propionic acids priorto packaging. Meat samples were kept at 4°C and with 2-day intervals were examinedperiodically for microbial (aerobic mesophillic count, coliform count, psychrotrphic countand anaerobic count), chemical (pH and TVN) and organoleptic (drip, color and odor)properties. The experiment was performed with 20 repetitions. Results showed that thedifference between untreated and citric-acid-treated samples was insignificant (P>0.05) frommicrobial and chemical viewpoints; meanwhile this difference was highly significantbetween untreated and acetic and also propionic-acid-treated samples (P<0.01). But thedifference between acetic-acid-treated and propionic-acid-treated samples were insignificant(P>0.01). With respect to microbial and chemical properties of meat samples, it is possible tokeep untreated samples for 4-days period, meanwhile this period for citric-acid-treated was 5and for lactic-acid and propionic-acetic-treated samples were 7 days. Results also showedthat the organoleptic properties of untreated and treated samples were insignificant (P>0.01).Therefore, it is possible to use 1% concentration of such organic acids in order to increase thestorage time of beef without causing undesirable effects on organoleptic properties.

This experiment was conducted to investigate the effects of citric acid and medicinal plants on growth performance، humeral immunity، serum proteins and intestinal microbial population in broilers. A total number of 225 Ross 308 (one-day old) broiler chickens were randomly divided into 4 treatments with 6 replicates of 3 chicks each. Treatments including: 1- basal diet (without any additives)، 2- basal diet + medicinal plants in equal mounts (0. 5%)، 3- basal diet +medicinal plants in equal mounts (0. 5%) + 0. 5% citric acid، 4- basal diet + 0. 5 % fenugreek + 0. 5 % citric acid، 5- basal diet + 0. 5% fennel + 0. 5% citric acid. Feed intake was significantly higher in treatment 5 compared to control and FCR was significantly higher in treatment 5 and 2 compared to treatment 3 and 4 (P< 0. 05). Total serum protein levels were higher in treatment 2 than in treatment 1 (P< 0. 05). Albumin / globulin ratio was significantly higher in treatment 3 and 4 compared to other treatments. The results indicated that the overall use of fennel and fenugreek plants and citric acid had satisfactory effects on growth and performance of broiler chickens.

Aflatoxin is considered as one of the most dangerous fungal toxins for human and animals. Crops contaminated with aflatoxin، causing economic losses in agriculture، food and livestock industries. In the present study، the effect of different concentrations of citric acid، propionic acid، and BsP4 strain of Bacillus subtilis on production of aflatoxin B1 by Aspergillus flavus was evaluated. Five treatment concentrations (0، 0. 5، 0. 75، 1 and 1. 25 percent of compounds)، in four replications were used to compare the production of aflatoxin. Appropriate concentration of the compounds were prepared and added to the PDA culture medium (Potato dextrose agar). After 21 days، the produced fungi on the PDA environment culture media were transmitted to rice containing flasks. Four flasks allocated to each studied concentration (20 flasks per each compound). The amount of aflatoxin B1 produced by each of the mentioned groups was measured by thin layer chromatography (TLC). The lowest yield of aflatoxin production (1. 2 ppm) was extracted from strain BsP4 of Bacillus subtilis in 1. 25 percent concentration. The highest toxin production was observed in the basal treatment (60. 8 ppm). The study found that along with increasing in the concentration of citric acid، propionic acid، and BsP4 strain of Bacillus subtilis، the production rate of aflatoxin is diminished to lowest possible rate.

The aim of this study was to investigate the effect of three concentration of citric acid on motility patterns of bovine epididymal sperms. For this purpose, 50 pairs of bovine testicles were collected immediately after slaughter form urmia abattoir and transferred to the laboratory alongside 5oc ice pack. Epididymal tail sperms were collected with a few incisions in vascular areas and transferred to hams f10 milieu with 10% fetal calf serum and counted after 15 minutes of incubation at 37oc in Co2 incubator. Concentrations of 50 million sperms per ml were proposal and in the normal sperm pH rang of 6.7-7.4, 0.1, 0.2 and 0.3 normal concentration of citric acid were added to sperm continuity micro tubes (normal concentration of acid equals 7 mg/ml of bovine serum) and at 15, 30, 45, 60, 90, 120, 180, 240 and 360 minutes the motility patterns of epididymal sperms were evaluated using the computer assisted sperms analyzing (CASA) method. Data were analyzed with one-way ANOVA using the SPSS 15 software. The results indicated significant differences in various indices of sperm motility patterns (Curvilinear Velocity, Straight-line Velocity, Average Path Velocity, Mean Angel Degree, Amplitude of Lateral Head Displacement, Beat-Cross Frequency, Linearity, Wobble) particularly at 0.3 normal concentration of citric acid compared with the control.