فهرست مطالب m. hedayatifard

The purpose of this study is to evaluate the effects of Sodium diformate (NDF) and Formic acid salt on the growth performance, nutrition indices, innate immune system, and digestive enzymes activity of 420 Huso huso (30.55±1.72 g) were randomly divided into seven experimental treatments. All groups were fed with the experimental diets for 60 days. The experimental diets contained 0.05%, 0.1% and 0.15% NDF and 0.05%, 0.1% and 0.15% Formic acid. Diet control was without any Acidifier. Results show that the best FCR and SGR were observed in the group fed with 0.1% supplemented food by NDF and formic acid (p<0.05) on the 30th and 60th day , respectively. The results show that the immunological parameters including total immunoglobulin (by 0.1% NDF), serum bactericidal activity (by 0.1 %NDF and 0.1 %Formic acid), and lysozyme activity (by 0.05 and 0.1% NDF) were affected significantly by Acidifier (p<0.05). The highest activity of trypsin and chymotrypsin was significant in groups 0.1 % supplemented food by NDF (p˂0.05) in the first 30 days. It can be concluded that the addition of 0.1% of NDF to beluga diets improves growth parameters decreases FCR, increases immunity levels and digestive enzymes activity.

This work is mainly concerned with the changes of amino acids and proximate compositions of Caspian Sea Beluga sturgeon (Huso huso) caviar after culture in freshwater. Proximate compositions did no differ between wild and farmed Beluga caviar (p>0.05). Eighteen amino acids were identified in wild and farmed Beluga caviars, but they had significant differences in some amino acids content. Isoleucine was the most abundant amino acid among total amino acids, which was 50.17±2.75 (mg/g) in wild caviar and was 26.83±0.82 (mg/g) in farmed ones (p<0.05). The essential amino acids content (EAA), in wild and farmed caviar were 132.66±6.8 and 110.16±7.35 (mg/g), nonessential amino acids (NEAA) were 107.92±5.68 and 121.79±4.08 (mg/g) and total amino acids (TAA) were 240.58±12.48 and 231.95±11.43 (mg/g) respectively (p>0.05). But the ratio of EAA/NEAA in wild samples 1.23±0 was significantly higher than farmed ones 0.9±0.03 (p<0.05). Functional amino acids (FAA) in wild and farmed samples were 96.1±8.66 and 116.8±9.65 (mg/g) (p>0.05), but the ratio of (FAA/TAA) in wild caviar was 0.40±0.02 and in farmed one was 0.50±0.02, which was significantly higher in farmed caviar (p<0.05). Delicious amino acids (DAA) were 54.9±1.89 and 54.86±2.01 (mg/g) in wild and farmed caviar and the ratio of (DAA/TAA) were 0.23±0 and 0.24±0 (p>0.05) respectively. The present study indicated that, farmed Beluga caviars were well balanced with the essential amino acids, functional amino acids and had a good EAA/NEAA ratio, so can be considered as a valuable food resource as well as the wild ones.

The present study was conducted to evaluate the effect of antimicrobial and antioxidant chitosan coating enriched with rice-bran extract on the shelf-life extension of trout fillet. Rice-bran extract was extracted with 80% methanol. Samples were separated into three groups; uncoated and without rice-bran extract (Control), coated with chitosan and coated with chitosan containing 2% rice-bran extract. Fish fillets were stored at refrigerated condition (4±1˚C) for 20 days. Lipid contents, chemical characteristics (peroxide value, thiobarbituric acid, free fatty acids, pH) and microbial (total bacteria and psychrophilic counts) and organoleptic properties (odor, color, texture, and general acceptability) were compared in fillets at various days of cold storage (0, 4, 8, 12, 16 and 20 days). Chitosan coating and chitosan coating containing rice-bran extract had positive effect in reducing the peroxide value, thiobarbituric acid, free fatty acids and pH. Microbial analysis indicated that coating enriched with rice-bran extract had a significant effect in the reducing the total bacteria and psychrophilic counts. Results showed that chitosan coatingand using rice-bran extract in coating had significant effects in reducing the chemical indices of spoilage and microbial properties and extension the shelf-life of trout fillets

In this study, shelf life of brined vacuum-packed (VP) Golden Mullet (Liza aurata) of Caspian Sea was assessed, considering its protein and lipid deterioration with effect of microbial population during 90 days of storage at 4ºC. Total Volatile Nitrogen (TVN) was measured to determine protein deterioration, Peroxide Value (PV) was analysed to determine lipid deterioration. Total Count (TC), Halophilic Bacterial Count (HBC) and possibility of Clostridium botulinum existence were measured to determine microbial population. TVN increased from 14.5 to 30.80 mg/100g, PV increased from 3.89 to 28.86(meqo2/kg), TC increased from  log 4.40 CFU/gr to log 5.70 CFU/gr and HBC increased from  log 4.75 CFU/gr to log 6.30 CFU/gr. Increasing in some of parameters, was found to be statistically significant in the VP brined golden mullet through out storage (P<0.05). No trace of Clostridium botulinum existence was detected during the period of storage. The results from this study clearly suggested that a combination of brining, vacuum packaging and storage at refrigerated temperature prolongs the shelf life of golden mullet. Based on data the best shelf life was found 30 days for VP brined golden mullet stored at 4ºC.