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A 90‐day feeding trial was carried out to examine the influence of fish oil (FO) substitution with blends of vegetable oils (VOs) on reproductive efficiency of female brooders and fluctuation in fatty acid (FA) profile of embryos in Oncorhynchus mykiss. A basal diet was formulated in which 20% (80FO/20VO), 50% (50FO/50VO), 75% (25FO/75VO) and 100% (100VO) of FO were replaced by mixture of VO. Reproductive performance of brooders was not affected by drastic alternations in FA profile of diets. The level of saturated and monounsaturated FAs (MUFAs) significantly increased, whereas the levels of long‐chain polyunsaturated FAs (LC‐PUFAs), mainly docosahexaenoic acid, profoundly decreased during embryogenesis. The concentrations of MUFA and n−6 PUFA increased in the eggs with increasing the incorporation of VO mixture in diets; however, the concentration of LC‐PUFA and n−3/n−6 PUFA ratio decreased. Haematological parameters and humoral immune responses including total immunoglobulin content, lysozyme and alternative complement pathway activities in brooders fed with the experimental diets did not statically different. In summary, incorporating mixture of various VO sources especially linseed and sunflower oils as good sources of α‐linolenic and linoleic acids, respectively, along with low levels of residual fat from fish meal in diet suggested a good strategy for providing the appropriate essential FA requirements of O. mykiss brooders for their successful reproduction. [ABSTRACT FROM AUTHOR]

In the present study, the effects of Artemia supplemented with 2‐β‐mercapto‐ethanol (β‐ME) treated yeast cell, Saccharomyces cerevisiae, on growth and reproductive performance, lysozyme activity, and disease resistance to Aeromonas hydrophila of freshwater ornamental species, Poecilia latipinna, were investigated. Within 60 days, molly fish were fed with three treatments including commercial food (T1), un‐supplemented Artemia (T2), and Artemia supplemented with β‐ME‐treated yeast cell (at concentration of 4 × 107 CFU/L of water) (T3). After the feeding period, the fish were exposed to 100 μl of a suspension (1.1 × 107 cells/ml) of A. hydrophila (BCCM5/LMG3279) and the cumulative mortality rates were recorded for 12 days. No significant difference was found between survival rate and growth performance of P. latipinna except for weight gain that was higher in fish fed through Artemia supplemented with β‐ME‐treated yeast cell compared to control group. Fecundity rate was significantly improved in fish fed using T3 with the maximum amount of 49.5 ± 2.29 per female (p < 0.05). Besides, lysozyme activity was significantly increased in group 3 (p < 0.05). Moreover, lowest fish mortality was significantly observed in this treatment (p < 0.05). In addition, the number of colonies formed by yeast cell in T3 (634 × 103 CFU/g intestine) showed significant difference with other treatments (p < 0.05). In sum, Artemia enriched with β‐ME‐treated yeast improved reproductive indices, immune responses, and resistance against A. hydrophila of P. latipinna. [ABSTRACT FROM AUTHOR]

In this study, metabolic responses of Persian sturgeon fingerlings to hyperosmotic condition were investigated by NMR-based metabolomics. Persian sturgeon fingerlings ( n = 2010, mean total weight: 3.2 ± 0.6 g; mean total length: 8.5 ± 1.5 cm) were held in freshwater ( FW) for 96 hr and then acclimated in brackish water ( BW) (12 g/L) for 24 hr. Blood samples were taken before and after salinity acclimation. The major metabolite changes corresponding to salinity acclimation were related to amino acids, osmolytes and energy metabolites. The plasma glucose levels increased significantly after 24 hr acclimation in BW ( p < .05). Other energetic metabolites (acetate, acetoacetate, beta-hydroxybutyrate, phosphocreatine, creatine, glycerol) showed no significant changes after 24 hr salinity challenge ( p > .05). The osmolytes (taurine, trimethylamine-N-oxide, choline, N,N-dimethylglycine) and amino acids (aspartate, glutamate, glutamine, leucine, phenylalanine, β-alanine, histidine, threonine, cysteine) declined significantly after 24 hr acclimation in BW ( p < .05). However, the levels of glycine elevated after 24 hr acclimation in BW ( p < .05). Other amino acids including aspargine, isoluecine, Tyrosine, Tryptophan, Valine, and Lysine showed no significant changes after salinity challenge ( p > .05). The considerable decreases in almost all plasma amino acids and all osmolytes showed specific importance of these metabolites in osmotic adaptation of fish in BW. Also, it seems that Persian sturgeon fingerlings rely more on oxidation of glucose to meet energetic requirements of osmoregulation than oxidation of lipids, as we observed no detectable changes in metabolites associated with lipid oxidation during osmotic acclimation in BW. Our results may help to understand osmoregulation in a chondrostei fish species from a metabolic approach. [ABSTRACT FROM AUTHOR]

The variable quality and high price of Artemia (Leach 1819) cyst products, used worldwide as live food, motivate aquaculturists to find an appropriate alternative, especially for fresh/brackish water organisms. In this study, Branchinecta orientalis (G. O. Sars 1901), a common fairy shrimp in north-western Iran, was reared for 15 days using effluent from trout ponds enriched with effluent filtrate as sole feed, or co-fed with microalgae ( Scenedesmus sp.). The effluent filtrate was replaced by algae at different ratios (25% and 50%), and feeding experiments were designed at densities of 100, 200 and 400 individuals/L in 3-L containers and at 100 individuals/L in 20-L containers. The results indicated that, at a certain density, the final length and survival were not significantly affected by different feeding regimes ( p > .05). In 3-L containers, the highest length and survival were observed at the lowest density. B. orientalis contained the highest amounts of proteins, carbohydrates and lipids, though, when co-fed algae, although the differences with the treatment fed solely effluent filtrate were often limited. Inclusion of algae in the diet also resulted in higher levels of a number of PUFAs. Our study proves that B. orientalis can be mass-cultured successfully using trout effluent as culture medium without additional microalgae. Fish pond effluent is massively available as a cheap food source. Recycling aquaculture effluent for this type of live food production contributes to lowering the use of natural resources and to less discharge of nutrient loads into natural water bodies. [ABSTRACT FROM AUTHOR]

We investigated the effects of concentration of the microalga Dunaliella tertiolecta on the growth and survival of fairy shrimp, Phallocryptus spinosa. Newly hatched nauplii were stocked into containers, maintained at different concentrations of D. tertiolecta (at 18, 36, 54, 72 and 90 × 106 cells mL−1). All treatments were in quadruplicate and each replicate was stocked with 100 larvae in a 2-L cylindrical bowl. We studied the survival and growth of the fairy shrimp after 3, 6, 9, 12 and 15 days of culture. The results indicated significant differences, in terms of growth and survival, of fairy shrimps fed at different algal densities. The highest and lowest growth and survival among the treatments were observed on Day 15, the highest in animals fed at a concentration of 90 × 106 cells mL−1 and the lowest in animals fed at a concentration of 18 × 106 cells mL−1. We conclude that the growth and survival of the P. spinosa increased with increasing density of algae, to a threshold level. Within certain concentration limits, the addition of D. tertiolecta substantially improved the performance of larval culture of P. spinosa, suggesting that this fairy shrimp has potential in terms of aquaculture development. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of dietary lactoferrin (Lf) on growth, haematology and non-specific immune response of rainbow trout Oncorhynchus mykiss ( Walbaum). Fish were fed an experimental diet containing 0 (as control), 50, 100, 200 and 400 mg Lf kg−1 diet twice daily for 8 weeks and sampled at 2, 4, 6 (immune function and growth), and 8 weeks (immune function, haematology and growth). Statistical analyses revealed no significant effects of dietary Lf on growth performance (specific growth rate, weight gain, feed conversion ratio, feed intake and condition factor) or haematological parameters (red and white blood cell count, haemoglobin, haematocrit, serum iron and total iron binding capacity [ TIBC]). Among the serum non-specific immune parameters, lysozyme activity increased significantly in fish fed 100, 200, or 400 mg Lf kg−1 feed for 8 weeks, whereas haemolytic complement activity increased in fish fed 100 and 400 mg Lf kg−1 diet after 6 weeks. The antiprotease activity increased in groups fed 100, 200 or 400 mg Lf kg−1 diet after 8 weeks. However, no significant effect was observed on serum peroxidase level. It can be concluded that feeding of rainbow trout on the diet supplemented with 100 mg kg−1 or higher for 8 weeks enhances the non-specific immune response. [ABSTRACT FROM AUTHOR]