Prolonged ecological changes can affect morphometrics and gene expression profile? Focusing on Hsp-70 and NLHS-induced Hsp-70 of Artemia urmiana.

BACKGROUND: In recent years, many aquatic ecosystems, including Urmia Lake, have undergone severe ecological tensions. This lake, the largest natural habitat of the brine shrimp Artemia urmiana, has progressively desiccated and its salinity has dramatically increased over the last three decades. In the face of the long period environmental stresses, understanding the adaptation and ecological plasticity mechanisms is the most interesting challenges in genetic and applied ecology. These mechanisms may probably be driven by inducing expression of some genes involved in adaptation such as Hsp-70 and also adjusting morphological parameters. But they are yet to be understood. Hence, the present work aimed to study the mechanisms, along with testing the hypothesis that non-lethal heat shocked nauplii originating from drought period can evoke Hsp-70 expression more than those from rainy period. METHODS: This study measured and analyzed morphometrical characters of adult male and female Artemia urmiana over three decades. Then, the influence of three-decade ecological crisis on Hsp-70 and non-lethal heat shock (NLHS)-induced Hsp-70 expression levels of nauplii of Artemia urmiana habiting Urmia Lake using Real-time PCR technique, based on cyst collections in 1994 (rainy period) to 2020 (drought period), was evaluated. RESULTS: The morphometrics results showed that the morphological characters were significantly shrunk in 2020 compared to 1994 (CI 95%, p < 0.05). Furthermore, our results depicted that, Hsp-70 expression level was significantly upregulated in response to the prolonged ecological crisis, (CI 95%, P < 0.0001), and also interestingly, the nauplii exposed to longe-term ecological crisis (belong to 2020) were able to increase Hsp-70 expression more than other ones in response to environmental stressors including heat. CONCLUSIONS: The present results showed the involvement of Hsp-70 in the adaptation of Artemia urmiana to long term ecological alteration at the cost of shrinking morphometric parameters.

Effects of dietary soybean lecithin on growth performance, blood chemistry and immunity in juvenile stellate sturgeon (Acipenser stellatus).

An eleven weeks feeding trial was conducted to determine the effects of different levels of dietary soybean lecithin (SBL) on growth performance, blood chemistry and immunity in juvenile stellate sturgeon (Acipenser stellatus). Fish were fed seven isoproteic (44% crude protein) and isolipidic (17% crude fat) diets containing graded levels of SBL: 0 (control), 1, 2, 4, 6, 8 and 10%. Results showed that dietary SBL supplementation significantly improved the final body weight (BW) and weight gain (WG). Fish fed 6% SBL showed the highest BW and WG values in comparison to fish fed the control diet (P < 0.05), whereas increasing SBL levels above 6% had little practical benefit in terms of somatic growth performance. The inclusion of SBL in diets significantly improved the immune response as data from lysozyme, total Ig levels, alternative complement, phagocytic and bactericidal activities indicated (P < 0.05). The broken-line regression analysis of immunological variable revealed that depending on the parameter considered, the optimal SBL levels in diets for stellate sturgeon juveniles varied. In particular, dietary SBL levels requirements in stellate sturgeon when considering the phagocytic activity rate were determined at 3.3%, whereas 4.1-4.2% were recommended when considering data from lysozyme, alternative complement and bactericidal activities. In contrast, the highest minimum dietary SBL content was estimated at 6.9% when data from total Ig levels were considered. These results indicated that dietary PLs are required for boosting innate immunity in stellate sturgeon, although their minimal level changed depending on the immunological parameter considered. Therefore, we assume that SBL levels comprised between 3.3 and 6.9% may be used as a prophylactic measure to improve the health status in stellate sturgeon. Red blood cell count, hemoglobin and hematocrit levels increased with increasing dietary SBL levels, especially in those sturgeons fed the diet with 6% SBL (P < 0.05). In addition, white blood cell counts significantly increased as dietary SBL levels increased from 4 to 8% in comparison to the control group. Blood biochemistry was also affected by different dietary SBL levels. In particular, significantly higher levels of glucose, cholesterol, HDL and triglycerides were detected in fish fed >6%, >4%, >2% and 2% SBL, respectively (P < 0.05). Based on somatic growth parameters, blood chemistry and systemic immunity parameters, diets containing ca. 6% SBL are recommended for juvenile stellate sturgeon.

Rancidity development of refrigerated rainbow trout (Oncorhynchus mykiss) fillets: comparative effects of in vivo and in vitro lycopene.

BACKGROUND: The problem of lipid oxidation in fish during storage is well known and is related to both temperature and storage time. Antioxidants could have a main role in limiting the deteriorative effects of lipid oxidation in fish. The present study aimed to investigate the effect of dietary supplement against postmortem addition of lycopene on the deterioration of trout fillets during storage at 4 ± 1 °C for 12 days. RESULTS: At the end of the feeding trial, no significant differences were observed with respect to the fatty acid composition of different dietary groups. However, a strong positive correlation (r = 0.96) was observed between fillet and diet lycopene levels. Lower indices of lipid oxidation (peroxide value and thiobarbituric acid) and lipid hydrolysis (free fatty acids) were observed in fillets that received lycopene (P < 0.05). Although exogenous lycopene was more effective (P < 0.05) than endogenous lycopene in delaying lipid oxidation, the fatty acid composition of fillets that received dietary lycopene supplement showed a higher stability (P < 0.05) during refrigeration storage. CONCLUSION: Accordingly, based on the time of appearance of off-odors and discoloration in fish fillets, exogenous lycopene, especially at higher levels, was more effective in terms of quality parameters. © 2017 Society of Chemical Industry.

Effects of diazinon on adaptation to sea-water by the endangered Persian sturgeon, Acipenser persicus, fingerlings.

To replenish the depleting populations of sturgeon fishes especially Persian sturgeon, Acipenser persicus in the Caspian Sea, millions of Persian sturgeon fingerlings are farmed through artificial propagation and released into the Iranian river estuaries annually. Fish osmoregulation is a vital physiological process that can be affected during the release. Many Iranian river estuaries are under the influence of pesticides originating from farming activities that may affect osmoregulation. In this study, Persian sturgeon fingerlings were exposed to sublethal concentrations (0, 0.18, 0.54, 0.9mgL(-)(1)) of diazinon for 96h (short-term trial) and 12 days (long-term trial) in fresh water (FW) and then fish were exposed in brackish water (BW) for 24h. After 96h and 12 days of exposure in FW, the lower levels of plasma triidothyronine (T3), thyroxine (T4), Na(+), Cl(-), K(+), gill Na(+)/K(+)- ATPase activity and number of chloride cells were observed in exposed fish (0.54 and 0.9mgL(-)(1) diazinon) compared to control group and 0.18mgL(-)(1) diazinon treatment. Also, higher levels of plasma cortisol (except 0.18mgL(-)(1) diazinon treatment in long-term trial) were observed in diazinon exposed fish compared to control group. However, gill Na(+)/K(+)-ATPase activity and the number of chloride cells were higher in fingerlings exposed to diazinon compared than control. When fish were exposed in BW for 24h, the following changes occurred: (a) in short-term trial: increases in cortisol and Cl(-) levels (0.54mgL(-)(1) diazinon ), Na(+) (0.9mgL(-)(1) diazinon ) and gill Na(+)/K(+)-ATPase activity (0.18mgL(-)(1) diazinon ). In control group, cortisol, T4, Na(+), gill Na(+)/K(+)-ATPase activity and the number of chloride cells increased significantly. (b) In long-term trial: increases in K(+) levels in fish exposed to 0.9mgL(-)(1) diazinon, Na+ in all diazinon concentrations and decreases in chloride cells number in fish exposed to 0.18mgL(-)(1) diazinon. In control group, significant increases were observed in cortisol, T3, Na(+) and chloride cells number. Finally, gill showed many histopathological damages during exposure in FW and BW. Our results suggest that the contamination of river estuaries with diazinon may alter the osmoregulation ability of released Persian sturgeon fingerlings, which could lead to a failure in their restocking program in the Caspian Sea.

The effect of various dietary MUFA content and n-6/n-3 ratios on rainbow trout (Oncorhynchus mykiss) fed on a whole plant protein based diet: growth performance, digestive enzymes activity, intestinal morphometry and fatty acids profile of muscle and liver.

The effect of diets with various dietary MUFA content and n-6/n-3 ratios, diets 1 (55.33, 1.00), 2 (25.30, 1.00), 3 (55.13, 2.05), 4 (24.92, 2.03), 5 (54.94, 8.06) and 6 (24.91, 8.06) and a control diet with fish oil (FO), diet 7 (33.60, 5.97), was studied on growth and digestive physiology of rainbow trout, Oncorhynchus mykiss. Juveniles, 14.65 g ± 0.17, were fed the experimental diets for eight weeks. Those fish fed diet 1 (55.33, 1.00) had the lowest growth and nutritional indices, while fish fed diet 6 (24.91, 8.06) possessed the highest indices. However, fish fed D7 (33.60, 5.97) was intermediate in this regard. Proximate body composition results revealed no significant differences among various experimental groups (P > 0.05). Fish fed on diet 1 possessed the highest alkaline protease activity, while fish raised on diet 2 showed the lowest enzyme activity (P < 0.05). Fish fed on diets 1, 3 and 4 had the highest lipase activity (P > 0.05). Amylase activity and intestinal parameters did not differ among groups (P > 0.05). MUFA contents of liver and muscle reflected the MUFA contents of the diets; however, liver PUFA contents was not affected by dietary PUFA contents (P < 0.05). However, 18:3n-3 contents of liver decreased as dietary n-6/n-3 ratio increased (P < 0.05). Furthermore, the liver 20:4n-6 contents considerably increased as dietary n-6/n-3 increased to 8.06 (P < 0.05). Muscle 22:6n-3 content of groups 1 to 6 was lower than group 7 (P < 0.05). In conclusion, rainbow trout was considerably capable of de novo synthesis of 22:6n-3. Meanwhile, increasing dietary n-6/n-3 ratio to 8.06 decreased the muscle 22:6n-3 content which requires further considerations regarding fish immune competence and nutritional quality for human consumption.

Life-history omnivory in the fairy shrimp Branchinecta orientalis (Branchiopoda: Anostraca).

Very little is known about the feeding of naupliar and juvenile life stages of omnivorous fairy shrimps (Crustacea: Anostraca). Here, we aim to reveal whether the fairy shrimp Branchinecta orientalis is an ontogenetic omnivore and at which age and ontogenetic stage they gain the ability to feed on zooplankton. We assess how food uptake rates change with age until reaching maturity by providing algae (pico- and nanoplanktonic unicellular algae) and zooplankton (rotifers and copepod nauplii) as food in individual experiments. We found that the fairy shrimp B. orientalis started to feed on both types of algal prey immediately after hatching. Nanoplanktonic algae likely represented the most important food source until reaching maturity. Moreover, fairy shrimps started to feed on zooplankton already when they were 7 days old. Slow-moving rotifers gradually gained importance in the fairy shrimp diet with time. Our results reveal an ontogenetic change in the prey spectrum of fairy shrimp. The systematic shift towards omnivory likely affects both phyto- and zooplankton community composition, possibly contributing to temporal changes in food web dynamics in fairy shrimp habitats, and temporary ponds, which may warrant more detailed investigations in future studies. Supplementary Information: The online version contains supplementary material available at 10.1007/s10750-022-05132-z.

Assessing nitrogen dynamics model and the role of artificial lagoon in effluent loading of shrimp farms in Gomishan wetland, southern Caspian Sea.

Shrimp farming increases the nutrients, especially nitrogen in the water resources reducing water quality. This study was conducted to evaluate the nitrogen dynamics in white shrimp (Litopenaeus vannamei) farms and the role of artificial lagoon (24 ha) in reducing nitrogen levels in Gomishan coastal wetland, the eastern Caspian Sea. The results indicated that at the end of the 4-month breeding period, the amounts of nitrogen and phosphorus introduced into Gomishan wetland were calculated as to 220.157 and 39 tons, respectively in a breeding area covering 830 hectares. Nitrogen values (based on nitrate) calculated based on the relationship between the basin and the discharge of the outlet channel of the site at the time of complete emptying of the farms, were calculated to be approximately 121.8 tons per breeding time that it had an important role in eliminating about 45% of nutrient pollution and reducing the concentration of dissolved nitrogen. Moreover, nitrogen isotopic trace was observed in shrimp samples, in similar levels in the samples of both shrimp pond and lagoon, which emphasizes the role of feeding from natural food, especially benthic fauna. Overall, due to the decline of Caspian Sea water level, Gomishan coastal wetland is drying, and the output of shrimp farms is currenly the only source supplying water for the wetland. Hence, appropriate management strategies could minimize the amounts of nutrients into the natural water whilst aiding wetland's survaival.

Effect of replacement of fish oil with different plant oils in Oncorhynchus mykiss broodstocks diets on egg and larval antioxidant defense development.

This study was undertaken to investigate the effects of feeding rainbow trout (Oncorhynchus mykiss) broodstocks with different ratio of plant oils to evaluate the changes in antioxidant defense status in the progenies. In the experimental diets, fish oil was replaced with different combination of plant oils including corn oil, olive oil, sunflower oil, and coconut oil, to gain different levels of polyunsaturated fatty acids (PUFA) and highly unsaturated fatty acids (HUFA) in the experimental diets. Fish fed eight weeks with experimental diets before reproduction. After spawning, samples were taken on days 0, 5, 10, 15, 20, 25, 30 and 35 after fertilization. The samples were homogenized, centrifuged and the supernatant was removed for determination of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) activity and malondialdehyde (MDA) content. Results showed that SOD activity was significantly increased from the first sampling to day 35 in all treatment groups. The CAT activity showed a downward trend, as the highest CAT activity was observed in the eggs immediately after fertilization. The GPX activity declined until day five and then showed an increasing trend. The MDA content did not show significant changes in different groups and at different sampling times. The antioxidant enzymes activity was significantly influenced by the dietary PUFA level in the experimental groups but no change in MDA content was recorded, suggesting that the different percentages of fish oil replacement used in this study could not result in oxidative stress in early life stages of O. mykiss.

Evaluation of the Impacts of Long-Term Enriched Artemia with Bacillus subtilis on Growth Performance, Reproduction, Intestinal Microflora, and Resistance to Aeromonas hydrophila of Ornamental Fish Poecilia latipinna.

The present study investigated the effect of enriched Artemia with Bacillus subtilis on growth performance, reproductive factors, proximate composition, intestinal microflora, and resistance to Aeromonas hydrophila of ornamental fish, Poecilia latipinna. Using a completely randomized design, the experiment included three groups. The first group was fed with commercial food without any probiotic. The second group was fed with unenriched Artemia, and the last group consumed long-time enriched Artemia with Bacillus subtilis. The bacteria B. subtilis with a density of 1 × 105 CFU mL-1 was added daily to Artemia culture medium. The total microflora and Bacillus subtilis counts were significantly increased in enriched Artemia compared to the unenriched group (P < 0.05). In fish fed groups, growth factors did not show any significant difference (P > 0.05). The maximum relative fecundity (28.65 ± 2.52 egg number g-1), fry production (62.93 ± 4.6 individual per female), and fry survival (70.97 ± 1.56%) obtained in the third group were found to be significantly more than those in the first and the second groups. Moreover, intestinal bacterial count for Bacillus revealed that the higher concentration of bacteria was significantly related to the third group (6.24 ± 0.11 log CFU g-1) (P < 0.05). Maximum protein and fat contents were observed in fish fed with Bacillus-enriched Artemia; however, no significant difference was found between control and unenriched Artemia groups (P > 0.05). The highest amount of ash was observed in fish fed with commercial food without any probiotic (P < 0.05). At the end of the feeding period, each of the three groups along with positive group (oxytetracycline 100 mg kg-1 of commercial food) was exposed to A. hydrophila (BCCM5/LMG3770) bacteria intraperitoneally. Based on the results, the lowest cumulative mortality was significantly found in group three (68.75 ± 3.6%) and positive group (62.5 ± 7.0%) compared to control and unenriched Artemia groups (P < 0.05). Hence, B. subtilis with a concentration of 1 × 105 CFU mL-1 during the period of Artemia culturing can improve the reproductive parameters, intestinal microflora, and resistance to pathogenic bacteria of Poecilia latipinna.

Replacing Dietary Fish Oil with Vegetable Oil Blends in Female Rainbow Trout Brood Stock Does Not Affect Breeding Quality.

To determine the effects of replacing fish oil (FO) with a mixture of vegetable oils (VO) in plant protein-rich diets on reproductive performance, the fatty acid profile of embryos as well as health indices of female rainbow trout (Oncorhynchus mykiss) brooders (initial mean body weight, 1.8 ± 0.1 kg), a 3-month feeding trial was conducted. Four isoproteic (ca. 42%) and isoenergetic (ca. 20 MJ/kg) diets were formulated in which 50% (FO50/VO50), 75% (FO25/VO75), and 100% (VO100) of FO were replaced by a mixture of VO, whereas the control diet (FO100) was prepared with FO as the major source of lipid. Fish fed the VO100 had the lowest fertilization (73.0 ± 2.5%), survival at eyed-embryo stage (62.5 ± 5.0%), and hatching rate (56.0 ± 4.7%) rates. Brood fish fed the FO50/VO50, FO25/VO50, and VO100 diets had higher levels of saturated and monounsaturated fatty acids in embryos in comparison with fish fed FO100 diet. The levels of docosahexaenoic acid of embryos gradually decreased during embryogenesis in all treatments, whereas the concentrations of eicosapentaenoic acid was greatly increased at hatching day (35 days after spawning). Regarding serum biochemical parameters, fish fed the VO100 diet had the highest serum glucose, cholesterol, and low-density lipoprotein levels. The results of the current study revealed that replacement of dietary FO with a mixture of VO up to 75% did not have any adverse effects on reproductive performance and health indices of O. mykiss females.

Growth Performance, Hemato-Immunological Responses, and Digestive Enzyme Activities in Silvery-Black Porgy (Sparidentex hasta) Fed Dietary Bovine Lactoferrin.

An 8-week study was conducted to evaluate three different diets supplemented with bovine lactoferrin (LF) at 0 (control), 800, and 1200 mg LF kg-1 diet on somatic growth, hemato-immunological parameters, antioxidant status, and digestive enzyme activities in silvery-black porgy (Sparidentex hasta) juveniles. Fish fed the 800 mg LF kg-1 diet had higher growth performance and feed utilization parameters than the other groups. Hematological and liver antioxidant parameters were not affected by dietary LF supplementation. Fish fed the 800 mg LF kg-1 diet had higher plasma lysozyme activity values than the other groups. Total protease activity was higher in fish fed LF-supplemented diets than the control group. Results indicated that diet supplemented with 800 mg kg-1 for 8 weeks enhanced somatic growth performance, lysozyme activity, and proteolytic digestive enzyme activities in S. hasta, as well as improving feed efficiency parameters like the protein efficiency and feed conversion ratios.

NMR-based metabolomic study on the toxicological effects of pesticide, diazinon on adaptation to sea water by endangered Persian sturgeon, Acipenser persicus fingerlings.

NMR-based metabolomics was applied to explore metabolic impacts of diazinon on sea water adaptation of Persian sturgeon fingerlings, Acipenser persicus. Fingerlings were exposed to sub-lethal concentrations of diazinon in freshwater (FW) for 96 h (short-term trial) and 12 days (long-term trial) and then exposed in brackish water (BW) (12 mg L-1 salinity) for 24 h. After 96 h and 12 days exposure in FW, identified metabolites (amino acids, osmolytes, energy metabolites) showed different change-patterns compared to control group (P < 0.05) as follow: (A) short-term trial: higher plasma levels of glucose, lactate (in all diazinon-exposed fish), acetate and acetoacetate (in 0.9 mg L-1diazinon treatment); lower levels of creatine (in all diazinon-exposed fish), trimethylamine-N-oxide, choline, taurine, betaine, N,N-dimethylglycine and almost all amino acids in fish exposed to high concentrations of diazinon (0.54 and 0.9 mg L-1 diazinon). (B) Long-term trial: higher plasma levels of lipid oxidation metabolites and almost all amino acids in fish exposed to 0.54 and 0.9 mg L-1 diazinon; lower levels of creatine, trimethylamine-N-oxide, N,N-dimethylglycine, betaine, choline (in all diazinon-exposed fish), glucose (in 0.54 and 0.9 mg L-1diazinon treatments) and taurine (in 0.9 mg L-1 diazinon treatment). When fish were exposed in BW for 24 h, the plasma levels of osmolytes decreased significantly in almost all experimental groups of short-term and long-term trial (P < 0.05). In short-term trial, the plasma levels of glucose in all groups and lactate in 0.18 and 0.54 mg L-1 diazinon treatments increased after salinity challenge (P < 0.05). However, a significant decrease was observed in lactate levels in 0.9 mg L-1 diazinon treatment (P < 0.05). Also, the plasma levels of amino acids decreased mostly in fish of control group than exposed fish (P < 0.05). The plasma glycerol concentration showed a significant decrease only in fish of 0.54 mg L-1 diazinon treatment (P < 0.05). In long term trial, the energetic metabolites (acetate, acetoacetate, glycerol) showed significant increases mostly in fish exposed to high concentrations of diazinon (P < 0.05). Phosphocreatine was detected only in groups exposed to 0.54 and 0.9 mg L-1 diazinon. Some amino acids decreased in control and diazinon-exposed groups while glycine (in control and 0.18 mg L-1 diazinon treatment), glutamine and alanine (in 0.9 mg L-1 diazinon treatment) elevated significantly after 24 h acclimation in BW (P < 0.05). Our results may help to understand the effects of pesticides on fish osmoregulation from a metabolic approach.

Morphometric and preliminary genetic characteristics of Branchinecta orientalis populations from Iran (Crustacea: Anostraca).

Branchinecta orientalis is a fairy shrimp endemic to the Palearctic region, from Mongolia to Spain. The patchy nature of its habitat is thought to result in a high degree of subdivision among populations, potentially promoting speciation. We combined morphometric characteristics with molecular phylogeny of cytochrome c oxidase I (COI) to test whether B. orientalis could be a species complex and whether there is any correlation between the genetic variation, morphometric characteristics and geographical variables. We studied six populations from Iran based on the comparison of morphometric and molecular datasets, we confirmed that the Aigher Goli (AIG) population is biometrically well separated from the Akh Gol, Hassar, Rashakan, Khaslou and Garagojanlou populations in northwestern Iran. The relatively high genetic divergence in the AIG from the other populations and its congruence with morphometric data were observed in B. orientalis populations. However, as these results were generated using a small sample size and on a limited sampling range, they should be considered as preliminary.

Effects of salinity and ultraviolet radiation on the bioaccumulation of mycosporine-like amino acids in Artemia from Lake Urmia (Iran).

We investigated the effects of salinity and artificial UV radiation on the accumulation of mycosporine-like amino acids (MAAs) in sexual and parthenogenetic Artemia from Lake Urmia. The nauplii hatched from the cysts were cultured until adulthood under two salinities (150 and 250 g L(-1) ) and two light treatments (PAR and PAR+UVR) in the laboratory. Finally, the Artemia were analyzed for their concentration of MAAs. In most of the cases, the higher salinity level applied was found to increase the MAA concentrations in both Artemia populations significantly. The acquisition efficiency of MAAs in both Artemia populations increased under exposure to UVR-supplemented photosynthetically active radiation (PAR) compared to those raised under PAR, except for Porphyra-334. It was observed that combination of UV radiation and elevated salinity significantly increased the bioaccumulation of MAAs. Thus, the presence of these compounds in these populations of Artemia may increase their adaptability for living in high-UV and high-salinity conditions prevailing in Lake Urmia. Higher concentrations of MAAs in the parthenogenetic population of Artemia could be probably attributed to its mono sex nature and higher adaptation capacities to extreme environmental conditions.