[ effects of iron nanoparticles in combination with Lactobacillus casei on growth parameters and probiotic counts in rainbow trout [Oncorhynchus mykiss] intestine]

Background: Today the use of natural substances plays a major role in improving the growth and immunity of aquatic organisms

Objectives: The purpose of the present study was to evaluate the effects of Iron nanoparticles with Lactobacillus casei as a probiotic on growth parameters and probiotic counts in rainbow trout intestine

Methods: Seven hundred and twenty fish with 12 +/- 0.49 g initial weight were prepared and after acclimatized to the laboratory conditions divided randomly into six groups. First group was selected as control, other groups were fed with a commercial diet supplemented with 108 CFU/g Lactobacillus casei [group 2], 50 micro g/kg Iron nanoparticles [group 3], 100 micro g/kg Iron nanoparticles [group 4], 50 micro g/kg Iron nanoparticles with 108 CFU/g Lactobacillus casei [group 5] and 100 micro g/kg Iron nanoparticles with 108 CFU/g Lactobacillus casei [group 6], respectively. Biometry and intestine bacteriologic examination were carried out at days 0 and 60

Results: Results showed that growth parameters [weight gain, body weight gain, specific growth rate, daily growth rate, and condition factor and food conversion rate] were significantly higher in group 5 compared with the other groups. Also, intestine bacterial counts increased by using Iron nanoparticles in combination with Lactobacillus casei. The fish that received 100 micro g/kg Iron nanoparticles and probiotic had significantly higher bacterial counts in their intestine compared with the other groups

Conclusions: Based on the obtained results we conclude that diet supplementation with Iron nanoparticles and Lactobacillus casei as a probiotic could significantly improve growth parameters in rainbow trout. However, these results would warrant further study on the clinical application of these agents

[Effect of dietary supplementation with zinc enriched yeast [Saccharomyces cerevisiae] on immunity of rainbow trout [Oncorhynchus mykiss]]

Zinc [Zn] is an essential trace element in all living organisms, and the first eukaryotic Zn uptake transporter was discovered in the yeast, Saccharomyces cerevisiae. Zinc-enriched yeast is a currently available Zn supplement. The purpose of the investigation was to compare and evaluate the effect of Zn enriched yeast in rainbow trout. The fish [mean body weight 10 +/- 0.5 g] were fed a commercial diet supplemented with 0 [control], 1 × 106, 1 × 107 and 1 × 108 CFU/g of Zn-enriched yeast for 60-days. Results showed that significant increase in serum lysozyme activity, complement activity and total immunoglobulin were seen in all treatment groups during feeding trial when compared to the control group. On the basis of our findings, Zn-enriched improved rainbow trout growth, some immune parameters and disease resistance.

The effects of short- and long-term diet supplementation with Iranian propolis on the growth and immunity in rainbow trout [Oncorhynchus mykiss]

Propolis, a resinous substance collected by Apis mellifera bees from various plant sources is transformed in the presence of bee enzymes. Short- and long-term effects of diet supplementation with ethanol extract of Iranian propolis [EEIP] was investigated on growth and immunity in juvenile rainbow trout. The fish [mean body weight 30 +/- 3.2 g] were fed a commercial diet supplemented with 0 [control], 1, 2 and 5 g/kg EEIP for 96 h and 0, 0.5, 1 and 2 g/kg EEIP for a 45-days. Rainbow trout growth performance significantly [P<0.05] increased by the dietary supplementation of Iranian propolis. Our results showed that significant increase in serum lysozyme activity, complement activity and total immunoglobulin were seen in all treatment groups during short- and longterm feeding trial when compared to the control group. On the basis of our findings, propolis improved rainbow trout growth performance and some immune parameters. Key words: Rainbow trout, Iranian propolis, Growth performance, Immunity

[ effect of yeast supplementation on the growth and immune system in rainbow trout [Oncorhynchus mykiss]]

Today, uses of natural substances are preferred to chemical and synthetic compounds for growth and immune enhancement of aquatic organisms. The aim of this research was to evaluate the effect of Saccharomyces cerevisiae extract and hydrolyzed powder on growth parameters and resistance of rainbow trout against temperature and hypoxia stresses with a bacterial challenge. For this purpose six hundred rainbow trout [50 +/- 5 g mean weight] were purchased from a local fish farm and transferred to the laboratory. After acclimatization to the laboratory conditions the fish were randomly divided into four groups each with triplicate. The first group was fed with a commercial diet [control] while the other groups received yeast extract, hydrolyzed powder and a mixture of them with the commercial diet. Fish were cultured in a 300 l polyethylene tank for 60 days and growth parameters were analyzed at days 0 and 60. Also, at the end of study the fish were challenged with hypoxia and temperature stresses with an experimental bacterial infection. Results showed that the extract and hydrolyzed powder of Saccharomyces cerevisiae in combination significantly [p=0.021] improved rainbow trout growth parameters compared with the control. The results also proved that fish survival significantly increased following feeding with a mixture of the extract and hydrolyzed powder after thermal [69.55 +/- 4.59], hypoxia [96.55 +/- 5.34] and yersiniosis [49.11 +/- 2.18] challenge than the control. Dietary administration of yeast extract with mixture of hydrolyzed powder of Saccharomyces cerevisiae could improve rainbow trout growth parameters and increase the resistance against stresses and disease

[Effects of bactocell probiotic and manan peribiotic on growth and immunity in rainbow trout [Oncorhynchus mykiss]]

Growth of population and food supply is one of the biggest problems in the world and aquaculture plays an important role in food production and supply for human beings. The aim of this study was to evaluate the effect of commercial probiotic [Bactocell] and prebiotic [Manan] on the growth and immune parameters in rainbow trout. Seven hundred and twenty fish were randomly divided into 6 groups with three replicates. The fish in the first group [control] were fed with commercial pelleted diet. The other five groups were fed with 100 mg of probiotic, 2.5 g [grams] of prebiotic, 5 g of prebiotic, 100 mg of probiotic and 2.5 g of prebiotic, and 100 mg of probiotic and 5 g of prebiotic per kilogram of food for 45 days, respectively. Then, all treatment groups were fed with usual food [without probiotic and prebiotic] for 15 days. Growth parameters were evaluated on days 0 and 60. Blood samples were collected for immunological experiments [level of Lysozyme, total antibody levels of serum, and activity of the complement system] on days 0, 15, 30, 45, and 60. All treatments fed with probiotic and peribiotic showed significant improvements [p<0.05] compared to the control group in terms of growth parameters including weight gain, special growth rate, and food conversion rate. The results of immunology also showed that fish fed with a combination of probiotic and peribiotic had a significant difference with other treatments and the control group [p<0.05]. The use of Bactocell and Manan improved the growth and immune response of rainbow trout