فهرست مطالب v. razavilar

Regarding to the roles of prebiotics and probiotics in feeding the aquatic animals, the aim of this study was to evaluate the effects of Pediococcus acidilactici, Mannan-oligosaccharide prebiotic and Beta-glucan on hematologic and immunologic parameters of the trout. 720 healthy rainbow trout were divided into four groups as the control group and groups treating with prebiotics, probiotics and both. After the treatment, immunologic, hematologic, growth-nutritional parameters were measured with various stressors indicating the positive effects of simultaneous probiotic and prebiotic treatment on all above-mentioned parameters and stress prevention in the trout.

This study was carried out to evaluate the feasibility of chitosan, a natural antimicrobial substance to improve the caviar shelf life. The effect of chitosan coating was carefully studied within 150 days storage time at -3°C in a standard situation. Both the caviar wrapped  by chitosan and the control sample, were packed in commercial glass Jars. Chemical, microbiological and sensory analyses were done during storage time. Results showed that the effect of chitosan coating on caviar samples was to maintain their good quality characteristics and extend the shelf life of caviar significantly (p<0.05) about 60 days in contrast with standard sample.

Aflatoxins (AFs) released by fungi are observed in the cow’s milk even after pasteurization. Aflatoxin M1 (AFM1) has particularly an incredible clinical significance, as a critical carcinogenic agent for humans. Several strategies have been implemented for lowering the AFM1 amount, such as the employment of probiotics, particularly lactobacilli or lactic acid bacteria (LAB). However, this strategy has not been applied routinely until today. This study aimed to evaluate the effect of three LABs on the reduction of AFM1 in traditional milk and cheese samples. In total, 85 milk (n=45) and cheese (n=40) samples were obtained from the open markets of Shiraz, Iran, from February to June 2018. Additionally, the AFM1 levels were evaluated, compared to those of the National Iranian Standard. The data were then analyzed in SPSS software (version 20) through the Chi-square test. Statistical analysis was performed at a 95% confidence level (p-value of <0.00001). Out of 50 purchased LABs, the efficient antifungal property and resistance to bile salts were observed in five strains. The mean value of these five strains was calculated after adding 5 ppm AFM1, compared to natamycin. The strains with a reduction in AFM1 level were sequenced and registered in the NCBI database.In total, 15 samples with contamination higher than the allowed limit included Penicillium spp, Aspergillus niger, Saccharomyces cerevisia, Saccharomyces paradoxus, and Yarrowia lipolytica.The results also showed reduced AFM1 levels in three LAB-treated strains. Lactobacillus fermentum CECT562 (T), Lactobacillus brevis ATCC14869 (T), and Enterococcus faecium LMG 11423 (T) had this capability to 0.05, 0.03, and 0.03 respectively. The National Iranian Standard should be implemented to have control over traditional dairy products with more care. The three LABs selected in the current study revealed a significant effect on reducing AFM1 levels in traditional milk and cheese.

One of the subjects attracted the interest of researchers in recent years in the field of biology is marine algae, due to their nutritional value, their benefits for health and their biological activities. In this study, steroid fractions of acetone extract of Colpomenia sinuosa (Phaeophyceae alga) from the Persian Gulf and Oman sea (Iran) have studied and evaluated for their antibacterial activity against pathogenic bacteria: one gram-positive bacterium (Staphylococcus aureus) and two gram-negative bacteria (Escherichia coli, Pseudomonas aeroginosa). Antimicrobial susceptibility tests have expressed in terms of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) of the test organisms with respect to the acetone extracts of Colpomenia sinuosa. Extracts of all tested marine algae have showed inhibition against all of the pathogenic microbes. In addition, the highest inhibition activity among all the extracts was shown from Cholestane fraction to S.aoreus and lower inhibition activity was shown from Oleic acid fraction to P. aeruginosa.

The present study was conducted to evaluate the effects of nanochitosan with sodium acetate and none-sodium acetate coating on Pseudomonas fluorescens and the shelf life of refrigerated rainbow trout (Onchorhynchus mykiss). 45 samples of rainbow trout filet in five positive and negative treatments including a control, 1% NCH(T2), 2% NCH(T3), 1% NCH+5% NaOAC1 (V/V, T4), 2%NCH2%+ 5%NaOAC1(V/V,T5), the negative groups  incubated by P. fluorescens bacteria (PF+NCH (1 and 2%) +5% NaOACl (V/V) (PF+NCH(1 and 2%)) and a negative control during the 16 days. Comparisons of microbial, chemical and sensory analyses were purely done on safe treatments periodically using one way ANOVA and Duncan tests. Results detected significant differences between the control group and both NCH+5% NaOAC1 (V/V), and NCH free of 5% NaOAC1 (V/V) in all amounts of microbial and chemical indices (p<0.05) and there were no significant differences between the two NCH groups (p>0.05). Sensory indices illustrated that filets treated with each groups of NCH±5% NaOAC1(V/V) received good points and their shelf life was 16 days, but control group settled in this status on sixth day of the test. For the two other treatments, shelf life storage increased and remained on 12 th and 16 th day, respectively. Furthermore, third day of the test showed high amounts of bacteria in the PF incubation treatment.  High levels of bacteria same as that in the control group were determined on sixth day in desirable samples and in NCH+ P. fluorescens, while there was an obvious bacterial reduction in bacterium mixed with NCH+NaOAC and kept for 12 days. Overall, utility of NCH+NaOAC increased the shelf life in refrigerator storage and decreased the amount of P. fluorescens in it.

There is a growing concern regarding the recurrent observation of aflatoxins (AFs) in the milk of lactating animals. Regarding this, the present study was conducted to assess the aflatoxin M1 (AFM1)-binding ability of three species, namely Lactobacillus rhamnosus, L. plantarum, and Saccharomyces boulardii, inAFM1-contaminatedmilk. The mentioned species were administeredatthe concentrations of107 and 109 CFU/mLto skimmed milk contaminated with 0.5 and 0.75 ng/mL AFM1 within the incubation times of 30 and 90 min at 4°C and 37°C. Lactobacillus rhamnosus was found to have the best binding ability at the concentrations of 107 and 109 (CFU/ml), rendering 82% and 90% removal in the milk samples with 0.5 and 0.75 ng/ml AFM1, respectively. Accordingly, this value at 107 and 109 CFU/ml of L. plantarum was obtained 89% and 82% with 0.75 ng/ml of AFM1, respectively. For S. boulardii at 107 and 109 CFU/ml, the rates were respectively estimated at 75% and 90% with 0.75 ng/ml of AFM1. The best AFM1-binding levels for L. rhamnosus, L. plantarum, and S. boulardii were 91.82±10.9%, 89.33±0.58%, and 93.20±10.9, respectively, at the concentrations of 1×109, 1×107, and 1×107 CFU/ml at 37, 4, and 37°C, respectively. In this study, the maximum AFM1 binding (100.0±0.58) occurred while a combination of the aforementioned probiotics was employed at a concentration of 1×107 CFU/ml at 37°C with 0.5 ng/ml AFM1, followed by the combination of L. rhamnosus and L. plantarum (95.86±10.9) at a concentration of 1×109 CFU/ml at the same temperature with 0.75 ng/ml AFM1. It was concluded that the use of S. boulardii in combination with Lactobacillus rhamnosus and L. plantarum, which bind AFM1 in milk, can decrease the risk of AFM1 in dairy products.

This study examines the antibacterial effects of Arum conophalloides on S. typhimurium bacteria at different temperatures (–18°, 8°, 16°, 24°, and 32°C) and time intervals (1, 2, 3, 6, 12, 24, and 48 days). This local plant was studied to determine the greatest effect caused by the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) as well as the antimicrobial effects of the extract. The Arum conophalloides essence was extracted via distillation or vapor using Clevenger hydro-distillation, using alcohol, chloroform, and water to extract the essence from Arum plant leaves (leading to three different extracts for comparison). In order to determine whether the extract used had minimum inhibitory and bactericidal effects, a microbial test method (isolate; 4, disk diffusion) was used in which two given dilutions (17,000 ppm and 35,000 ppm) were obtained and one of the two groups (dilutions) was selected as the control. Three groups of MIC and MBC and a control group were evaluated on plate-count agar using pour-plate technique at the designated temperatures and time intervals. Total numbers of bacterial colonies were counted. The resulting data were statistically analyzed with SPSS, with pS. typhimurium bacteria and based on our result, a connection can be made between Arum conophalloides extraction method and MIC, MBC.