[Comparison of the effects of a fish-oil containing diet, a diet with a fat composition based on the Iranian fat consumption pattern, and a standard diet on pathologic changes in the wistar rat liver]

Information of the effects of different types of fat on liver pathology is limited. The present study was designed to compare the effects of a fish-oil containing diet, a diet with a fat composition based on the Iranian fat consumption pattern, and a standard diet on pathologic changes in the Wistar rat liver. Thirty female Wistar rats were randomly allocated to one of three diets: a standard diet [containing soy bean-oil], a diet containing fish oil, and one containing mixed oil based on the Iranian population fatty acid intake. Dams in each group were fed one of the diets during pregnancy and lactation, and the pups were weaned onto the same diet. Hepato-cellular pathology in pups was assessed on days 21 and 70 postnatal. Data were analyzed using the SPSS software and Kruskal-Wallis test. Fish oil-fed and Iranian mixed oil-fed pups showed more ductular cell hyperplasia on day 70 postnatal, as compared to the soy bean oil-fed pups [p=0.005]. The pathologic changes increased from day 21 to day 70 in all the 3 groups [p=0.002]. The magnitude of the increase was significant in the fish oil-fed rats [p=0.007]. A diet containing fish oil as the only fat source and a diet with the Iranian population fatty acid intake pattern may lead to pathologic changes in the rat liver. It seems this adverse effect increases by age of the animal

[Comparison of bench-scale production of xanthan by xanthomonas campestris in solid state and submerged fermentation]

Xanthan gum is an important natural biopolymer with numerous applications in various technologies, specially food industry. In this research, microbial production of xanthan by Xanthomonas campestris PTCC1473 from sugarcane molasses and date sugar in submerged fermentation [SmF] and also dried date waste [cake produced after pressing] in solid state fermentation [SSF] were compared. The Plackett-Burmann design [PBD] was used in this study. Chemical composition and characteristics [dried cell weight, nitrogen, moisture, ash and pH] of the substrates were determined. Yeast malt broth [YMB] and yeast malt agar [YMA] were used as maintenance and inoculum preparation media, and incubation was performed in a shaker incubator [at 28degreeC, 72 h and 200 rpm]. The fermentation medium was centrifuged at 5degreeC and 21055 multiplied by g for 50 minutes and the supernatant separated from the pellet for further xanthan extraction. After precipitation of xanthan by isopropanol, resuspension and further purification by centrifuge [at 2056 x g], the xanthan dry weight was determined. The effects of several variables, including the kind and concentration of carbon [date sugar and sugarcane molasses], nitrogen [ammonium nitrate and diammonium phosphate] and phosphorus [KH2PO4], temperature, shaking, and size and age of inoculum, on the yield were determined. The most effective variables were found to be the type of carbon and nitrogen sources in the medium. It can be concluded that both the yield [% w/w of xanthan/consumed sugar] and productivity [g/g.day xanthan/consumed sugar] are higher in SmF [22.4 and 7.46] than in SSF [13.3 and 4.43]. In addition, date extract results in a higher productivity than date waste and sugarcane molasses. The xanthan yield could be increased by changing the composition and physical conditions of the culture medium