فصلنامه تغذیه آبزیان
سال ششم شماره 2 (پیاپی 12، تابستان 1399)

The Lavandula angostifolia is a medicinal plant that has the property of strengthening the immune system. In the present study, the effects of different levels of L. angostifolia extract on growth performance, survival rate and blood indices of the grass carp (Ctenopharyngodon idella) (11.01 ± 0.05 g, 15.5 ± 0.3 cm) was investigated. The fish were didtributed in 4 treatments (0 (control), 0.1% (T1), 0.5% (T2) and 1% (T3)). The fish were fed for 8 weeks. The results showed highest and lowest weight in both leaves and lavender groups in T3 and control group, respectively (p < 0.05). The highest and lowest FCR were observed in the control group and T3 treatment, respectively (p < 0.05). WG, BWI and PER values in T3 had the highest value (p < 0.05). CF in treatments containing common lavender was higher than control (p < 0.05). There was no significant difference in HSI (p>0.05). The highest and lowest HSI was observed in control and T2 groups. No mortality was observed in the groups. The hematocrit, hemoglobin, RBC, WBC had significant difference (p < 0.05) but lymphocytes, monocytes, neutrophils, MCH, MCV and MCHC showed no significant difference (p>0.05). The levels of lysozyme, IgM and globulin in experimental treatments were significantly higher than control (p < 0.05). In general, the extract of common lavender has a positive effect on improving the biological status of grass carp.

Effects of the microencapsulated Lactobacillus rhamnosus JCM 1136 on the blood parameters and body composition of rainbow trout (Oncorhynchus mykiss). In this study, first the probiotic bacteria L. rhamnosus JCM1136 were microencapsulated with coatings of sodium alginate and chitosan. Then, they were added to the food pellets and given to the fingerlings. For this purpose, 225 rainbow trout fingerlings (6.23 ± 0.17 g) in 5 treatments and each treatment with 3 replications were placed in California trays (220 × 30 × 15 cm). Treatment 1 (T1): Fish fed with 108 CFU/g microencapsulated probiotics with sodium alginate, treatment 2 (T2): fish fed with 108 CFU/g microencapsulated probiotics with sodium alginate and chitosan, treatment 3 (T3): fish fed with 108 CFU/g capsule-free probiotics, treatment 4 (T4): fish fed with probiotic-free sodium alginate-chitosan capsules and control treatment 5 (T5): fish fed with commercial free-probiotic and capsules pellets. At the end of the course, results indicated that the fishes fed with diet containing sodium alginate-chitosan microencapsulated probiotics in terms of blood parameters such as red blood cells, white blood cells, hemoglobin and hematocrit as well as the amount of carcass protein compared to control and other treatments were in better condition, which These differences were significant with control treatments fishes (p < 0.05).

The current study carried out to investigate the effects of adding salt (NaCl) in the diet of beluga, Huso huso and its impacts both on the function of intestinal enzymes and growth indices and food efficiency. In this regard, 480 species of Huso huso with a mean weight of 173.8 ± 0.49 g stocked in 12 fiberglasses 2000-liter tanks for 12 weeks. They fed a diet containing different levels of NaCl including 0, 3, 6 and 9 percent. Growth indices including final weight, SGR and daily growth showed significant differences in fishes of all treatments, except the fishes fed the diet containing comparing control group (p < 0.05) Weight gain percentage of fed fish at 6% sodium chloride level was significantly higher than fish fed control but no statistically significant difference was observed between other treatments. The mean FCR in fishes of control group was significantly higher than other treatments (p < 0.05). The mean rates ofrate of intestinal enzymes including Alkaline phosphatase, protease, lipase and amylase in the fishes fed by different levels of NaCl were significantly more than control group (p < 0.05). It is suggested to achieve a higher growth rate, improve food efficiency, reduction of production costs and enhancement of intestinal enzymes function. appropriate percentage of added NaCl is to be 3-6% per kilogram of diet for farmed beluga of at 150 to 700 g.

Taurine (2 amino ethane sulfonic acid), is a semi-essential amino acid and an end product of the sulfur amino acid metabolism. The aim of this study was improving Rosy barb (Pethia conchonius) pigmentation. The fish (average weight 32 ± 7 mg and length 12.83 ± 1.82 mm) were divided into five different groups including control (basic diet without taurine and astaxanthin) and four different levels of taurine (0, 100, 250 & 500 mg/kg diet) with constant amount of astaxanthin (100 mg/kg diet) and fed for 60 days. The pigmentation analysis was done using digital camera photography and whole body biochemical carotenoid analysis and showed that the fish fed on 100 + 250 mg/kg of astaxanthin & taurine respectively had the highest levels of pigmentation. Adding taurine up to 250 (mg/kg diet) caused increasing total carcasses lipid, plasma triglyceride, cholesterol, LDL & HDL levels in compression to the fish fed on control diet (p<0.05). It could be concluded that dietary taurine supplementation could affect fish lipid metabolism and improve astaxanthin absorption, which lead to better pigmentation in Rosy barb.

 The aim of this study was to investigate the effect of chitosan nanoparticles containing folic acid in the diet of rainbow trout, Oncorhynchus mykiss on growth and survival indices. For this purpose, rainbow trout with an average weight of 30 ± 2 g were divided into five experimental treatments: 0, 0.1, 0.25, 0.5 and 1 mg of chitosan/folic acid nanoparticles per kg of diet. Each treatment containing 25 fish in 3 repetitions in 15 tanks (500 liter) was designed into a closed-circuit breeding system. After making a manual diet and adapting the fish to the new conditions they were fed for 8 weeks. At the end of the experiment period, growth and survival indices were evaluated. The highest growth rate was recorded in the treatment of 1 mg/kg of chitosan/folic acid nanoparticles at the rate of 69.23 ± 4.34 g. With increasing Ch/FA nanoparticles levels in the formulated diets, the feed conversion ratio decreased linearly, which in fish fed with 1 mg/kg diet supplemented with chitosan / folic acid nanoparticles reached to 1.29 ± 0.08 (p < 0.05). On the other hand, the survival rate was the same in all treatments, but at the end of the period, losses were clearly observed in the control. The results showed that increasing the level of chitosan/folic acid nanoparticles in formulated diets will increase the growth rate and have a positive effect on growth index.

 This study was performed to evaluate the effect of immune system stimulants (vitamins E, C and selenium) on biochemical and immunity indices of Late calcarifer. For this purpose, two treatments were selected. Treatment 1 or control group was fed with food without immune stimulant and treatment 2 with diet containing vitamins E, C and selenium at 2% of the biomass weight. Finally, growth efficiency indices were compared in two treatments. Results showed final weight of the control and treatment groups was 761.33 ± 35.8 g and 850.00 ± 5.77 g, respectively. The specific growth rate of the control and treatment groups was 1.3 ± 0.02 and 1.35 ± 0.01 but the feed conversion ratio did not show a significant difference. Hemoglobin and erythrocytes showed a significant increase compared to the control in treatments containing immune stimulants and supplementation (p < 0.05). White blood cells ranged from 41417 ± 2964.84 in the treatment to 42500 ± 683.13 in the control treatment. The number of red blood cells in the control treatment was 2810000 ± 19.1763 and the recipient treatment was 3951667 ± 14588.84. Immune system stimulants including vitamins E, C and selenium can play a role in improving the growth, blood, biochemical and safety indices of farmed Late calcarifer.