جستجوی مقالات مرتبط با کلیدواژه "بایوفلاک" در نشریات گروه "شیلات"

In this study, growth performance, antioxidant enzymes activity, and bacterial load were investigated in recirculating aquaculture system (RAS), biofloc-RAS (BRAS) and biofloc system. Common carp juveniles with initial body weight of 70.99±0.91 g and stocking density of 6.25 kg/m3 were farmed in nine designed systems for three months. The mean weight, specific growth rate (SGR), weight gain, and food conversion ratio (FCR) were measured once every 15 days, bacterial load at the beginning, middle and end, and antioxidant enzymes at the end of the study period. Results showed the mean weight, weight gain and SGR in the biofloc system were significantly lower than other systems (p<0.05). However, the fish in the RAS and BRAS did not show any statistical difference in terms of the mentioned indicators. The FCR in the biofloc system (1.96) was significantly (p<0.05) higher than the RAS (1.59) and the BRAS (1.55). The highest amount of total antioxidant capacity and catalase enzyme activity was observed in the biofloc system and the lowest amount of superoxide dismutase enzyme activity was in the BRAS. In terms of bacterial load, a significant difference was observed amongst the three systems. So that the lowest value was observed in the RAS and the highest value was in the biofloc system. In general, it can be concluded that growth performance and feeding efficiency of common carp in the RAS and BRAS were better than the biofloc system in conditions of low water exchange.

The basis of biofloc technology is biomaterials, dead organic particles, microbes, algae, protozoa and other organisms. The present study was conducted to evaluate the effect of biofloc system on blood indices in juvenile H. huso in the International Sturgeon Research Institute of the Caspian Sea during one year. For this purpose, 120 fish with an initial weight of 168.2 ± 2.9 g were introduced in 6 fiberglass tanks with volume 2000 liter. Treatments included control treatment and one biofloc treatment and each treatment had 3 replications. During the experiment blood and immunological indices of fish were measured. In terms of blood indices, biofloc treatment was better. The lowest number of white blood cells, neutrophils and the highest number of red blood cells, hematocrit and Measn corposcular volume (MCV) were observed in the biofloc treatment and there was a significant difference with the control treatment (P<0.05). Immunological results showed the levels of immunoglobulin M, lysozyme and total immunoglobulin in biofloc treatment improved compared to the control, but were not significant difference (P <0.05). In addition, biofloc treatment had more bacteria than the control and showed a significant difference (P<0.05). Therefore, biofloc treatment can be selected as the superior treatment according to its performance. Because it improved the conditions and increased the efficiency of the breeding system and also improved the living conditions.

The aim of this study was to investigate the effect of different carbon to nitrogen ratios and its method for rearing common carp (Cyprinus carpio) in the biofloc system through immunological parameters. A total of 750 fish species with a mean weight of 17 ± 0.5 g were selected and randomly divided into 30 fiberglass tank with a volume of approximately 250 liters of water. The treatments included three levels of carbon to nitrogen with different levels of 15, 20 and 25 with three levels of dietary protein including 25%, 30%, and 35% by three replications during the 56-day period of trial. Also, a control group was fed with 35% dietary protein in usual system with water exchange. Based on the results, The amount of total protein, albumin, and globulin showed significantly a numerical increase with increasing the percentage of dietary protein in biofloc treatments compared to the control treatment (P<0.05). Also, the lowest serum total protein and albumin were observed in the control treatment. Furthermore, the lowest serum bactericidal activity, lysozyme, and total complement (ACH50) were in control treatment that significantly different from the biofloc treatment with 30% protein and the ratio of C/N 15 (p<0.05). As a result, using the optimal ratio of carbon to nitrogen 15 with 30% protein due to the activity of lysozyme and complement is a good strategy for the production of common carp juveniles at the early stage in this system.

This study was carried out to compare the effect of different culture systems on the growth performance and body composition of common carp (Cyprinus carpio). Fish juvenile was selected by initial average weight of 21.5 ±0. 3 after designs the systems and adaptation period were randomly distributed in fiberglass tanks (with 100 liters capacity). The experiment lasted for 2 months.  At the end of experiment, growth parameters including final weight, weight gain percentage, specific growth rate, survival; and whole body proximate analyses including protein, fat and ash levels were examined. Finally, there were significant differences in final weight, specific growth rate, and feed conversion ratio and survival rate between experimental treatments (p<0.05). There was no significant difference between treatments (biofloc, recirculating aquaculture system) for whole body’s moisture, fat and protein (p>0.05). But there was a significant difference among body protein, ash and fat among control 2 treatment and other treatments (p<0.05). Also there was no significant difference between biofloc and recirculating aquaculture system for lysozyme and complement activity in treatments whereas the fish in biofloc showed a significant higher superoxide dismutase than the others (p<0.05). The results obtained in this experiment, suggest that biofloc improves growth parameters, immune response even with decreasing percentage of daily feeding in common carp.

In the present study, the effect of different carbon sources on water quality and growth performance of common carp (Cyprinus carpio) fingerlings by adding synbiotic into biofloc system (BFT) were investigated for 45 days. Three experimental treatments (B, C and D) containing corn, wheat and barley flours together with a control group (A) were prepared. The used synbiotic was a mixture of Bacillus circulans and B. lichiformis along with a Celmanax liquid commercial prebiotic at a final concentration of 1.5×108 CFU/ml to each treatment. Fish fingerling (15.98±1.93 g) was distributed randomly into 12 tanks (4 treatments × 3 riplicated) with 30 liters of capacity. At the end of the experiment, the nitrate, total hardness and total suspended solidsin in all treatments significantly increased compared with the control (P<0.05). While, the dissolved oxygen in all treatments was lower than the control (P<0.05). NO3 was measured higher than the control only in corn and barley treatments (P<0.05). The highest final weight (40.31±11.20 g), SGR (1.59±0.27%), TGC (0.98±0.09%), condition factor (2.21±0.17), FCE (106.09±29.47%), PER (4.71±1.31), PEL (18.22±5.04) and PEE (0.13±0.04) were recorded in corn flour treatment. However, the lowest feed conversion ratio (1.01±0.25) and relative feed intake (11.94±3.79%) were observed in corn flour treatment (P<0.05). The highest excretion rates of ammonia (1011.45±14.27 mg.kg-1BW.day-1), urea (25.30±3.57 mg.kg-1BW.day-1) and energy wast by excretion rates of ammonia (25.36±3.50 mg.kg-1BW.day-1) and urea (6.21±0.78 mg.kg-1BW.day-1) were recorded in barley flour (P<0.05). In conclusion, the results demonstrat that the use of corn flour with synbiotic in the BFT system, compared to other carbon sources was more effective to improve the water quality and promoting of growth preformance of common carp fingerlings.

The aim of this study was to evaluate the effects of biofloc (with addition of spoilage date palm extract (SDE) and molasses as sugar sources) on bacterial load of water, growth performance and intestine of Litopenaeus vannamei using diets containing different protein levels. Four biofloc treatments were designated including the biofloc treatment with SDE + a diet containing 25% protein (P25), biofloc treatment with molasses + a diet containing 25% protein (M25), biofloc treatment with SDE + a diet containing 15% protein (P15), biofloc treatment with molasses + a diet containing 15% protein (M15) and the control treatment with a diet containing 38% protein (Control). All treatments were conducted in triplicates. A 35-day study was conducted on 35 juvenile shrimp (with average weight of 5.37±0.33 g) which randomly stocked in fifteen tanks (each 300 L) at a stocking density of 175 shrimp m−3. The highest amounts of growth parameters (weight gain, Feed Conversion Ratio (FCR), growth rate and survival) were observed in P25 treatment and the lowest amounts of growth parameters were observed in the control (P<0.05). Moreover, the highest percentages of body weight index, feed efficiency and specific growth rate were observed in P25 and the lowest percentages of those were observed in M15 treatment (P<0.05). Results showed that the number of total heterotrophic bacteria was increased during the study and the numbers of total heterotrophic bacteria in all biofloc treatments were higher than that of the control. The highest and the lowest numbers of fungi, vibrio and bacillus were found in P25 treatment and the control treatment, respectively. The length of the epithelial cells of the intestine was increased in all biofloc treatments as compared to the control but this difference was significant in the first abdominal segment, only. The result demonstrated that the effects of SDE were better than molasses, which could be due to the presence of useful compounds such as the growth and immunity promoters in it.