International Journal of Aquatic Biology
Volume:10 Issue: 6, Dec 2022

This work aimed to investigate the effect of dietary Lactococcuslactisand Bacillus subtilison the immune responses, intestinal microbiota, and resistance to pathogens of Oscar, Astronotus ocellatus. During 70 days trial, 300 juveniles (8.96±0.033 g) were fed diets enriched with L. lactisand B. subtilis. The treatments included 150, 300, 450 mgkg-1of dietary L. lactis(LL150, LL300, LL450); 150, 300, 450 mg kg-1of dietary B. subtilis(BS150, BS300, BS450); 150, 300, 450 mg kg-1of diet an equal mixture of L. lactisand B. subtilis(MIX150, MIX300, MIX450); and a non-supplemented control group. At the end of the rearing period, histological, immunological, and intestinal microbiota indices in treatments were investigated. To evaluate disease resistance, 15 fish in each treatment were infected in each treatment by Aeromonas hydrophila. The results showed that adding B. subtilisand L. lactis, particularly in MIX300, reduced the anaerobic heterotrophic bacterial microbiota and increased lactic acid bacteria (LAB) in fish. The highest white blood cell (WBC) level was recorded in the LL150 group. The lymphocytes in fish fed LL150, LL300, MIX150, and MIX300diets were changed andneutrophils of LL150, LL300, LL450, MIX300, and MIX450were significantly increased. Monocytes in fish fed MIX300and MIX450diets raised significantly. The IgM, ACH50, and lysozyme levels in fish-fed diets enriched by bacteria, especially in LL450, were significantly higher than the control treatment. The intestinal villi in LL450, BS150, and MIX450were significantly higher, showing lower damages than the other treatments. The survival rates of the infected fishes were higher in MIX150and MIX300 groups.

Current work aimed to isolate and characterize symbiont bacteria of Stylissa massa inhabitingRote Island of East Nusa Tenggara, Indonesia. The symbiont bacteriaare potential candidates for producing antimicrobial bioactive compounds. A total of 22 bacteria were isolated from S. massa with different characteristics. These isolates were screened to understand their capability to inhibit the growth of Escherichia coliand Staphylococcus aureus. Further, the secondary metabolites of the SM10 isolate, with the best inhibition results. This isolate could inhibit pathogenic bacteria of E.coli (11.24 mm) and S. aureus(12.11 mm). The molecular identification using 16 S rRNA, revealed that the SM10 isolate is Pseudomonas aeruginosa. Based on the GC-MS results, the SM10 isolate had produced two alkaloid compounds, pyrrole alkaloid (hymenialdisine) and bromopyrrole alkaloid (agelongine and spongiacidin D), and 2 unknown compounds. This finding showed that S. massahas symbiont bacteria isolates that can be used in the biochemical industry

The current study was conducted to determine the effect of dietary fat sources on fish growth, resistance, and antioxidant ability in common carp. The experimental diets were based on various fat sources, including fish oil (FO), linseed oil (LO), sesame oil (SO), and a mixture of LO and SO (SLO). The common carp (23.8±0.7 g) were distributed into a 100 L-tank system at a density of 25 fish per tank. Fish were fed experimental feed to satiation for seven weeks, and the consumable feed amount was recorded daily. After a 7-week trial, fish were infected with Aeromonas veroniiat a dose of 0.43×106CFU/mL and monitored for 14 days. The fish mortality was checked daily. Fish livers were sampled after feeding and on the second day post-bacterial injection to analyze the antioxidant parameters. The results indicated that the fat sources did not affect the fish growth, feed conversion rate, survival, and cumulative mortality in the challenge test but modified the antioxidant ability in fish liver. The malondialdehyde activity in SLO-fed fish was lower than that in FO group at the end of the feeding trial, while the glutathione activity in SO-fed fish was higher than those in other plant oil-fed fish after the bacterial challenge. The highest values of superoxide dismutase activity were recorded in LO fish after the nutritional trial and FO ones after the challenge test

This study aimed to investigate the nesting area of green turtle, Chelonia mydas, and hatchlings released in Daraan Beach, Jiwani, Pakistan, with providing recommendations for their conservation. Survey trips were conducted along Daran Beach, Jiwani, for the current study from September 2020 to August 2021. We examined the nests, nesting turtles, hatchlings, and turtle tracks during this period. In addition, interviews were conducted with representatives of the local community, fishing industry, and wildlife service to obtain further information. On Daraan Beach, the three green turtle nesting locations (Rindani Taak, Dedalah Taak and Shaheed Taak) were recorded. The results showed that September had the fewest hatchlings and January had the most hatchlings,whereas, in the months of May, June, July, and August, there was no hatchling record. The results also revealed increasing hatchlings during our study during 2020-2021 due to the Wildlife department’s efforts to protect and conservegreen turtles at Daran Beach. The green turtle population in Jiwani is in danger due to human activities such as climate change, global warming, sea level rise, pollution, and poaching.

Duck mussel, Anodonta anatina is a habitat generalist inhabiting both lentic and lotic aquatic ecosystems. Due to high morphological similarity and phenotypic plasticity, A. anatina has sometimes been misidentified as A. cygnea. Here, morphological and molecular studies were conducted on Anodontamussels inhabiting North Iran and Finland. The individuals were collected from Anzali Wetland, Tajan River (North Iran) and Jyväsjärvi Lake (Finland). The COI sequence analysis showed the existence of A. anatinain the sampling areas. The Iranian and Finland specimens showed three and two haplotypes, respectively. The Iranian haplotypes were placed in a single clade, while the Finland haplotypes were clustered with those of Central Europe. The mean P-distance between these two clades was 2.4. The median-joining network showed that the Iranian haplotypes were lumped into a single haplogroup, while the Finland ones were in the same haplogroup as those from Central Europe. The Mediterranean haplotypes were the most divergent haplogroup from both Iranian and Central European haplogroups. In morphological characteristics, the shell pattern of all individuals from both Iranian and Finland specimens was stretched and slightly compact with light/dark brown periostracum. The mean length of the specimens from Anzali Wetland was significantly higher than those of Tajan and Jyväsjärvi. No significant difference was observed in morphometric characteristics betweenTajan and Jyväsjärvi populations. The results did not indicate significant variation in shell morphology in the studied groups. In this regard, the conventional linear measurements can be supplemented using more complex geometric morphology in further studies

Zinc oxide nanoparticles (ZnO NPs) are currently used in several fields, including removingdissolved metals and organic contaminants from wastewater by adsorption and/or photocatalytic mechanisms. Thereafter, ZnO NPs can be released into the environment and reach aquatic ecosystems, where their interaction with dissolved trace metals can alter their solubility and toxicity. For these reasons, the present study aimed to assess the enhanced toxicity of ZnO NPs and dissolved copper (Cu2+), using the littoral rotifer, Lecane papuana as a test organism. The ZnO NPs synthesized in this research are colloidally stable at high concentrations in either distilled water or test media according to their Z-potential and hydrodynamic diameter. Thus,they remain as colloids along the duration of the exposure experiments. Acute toxicity tests showed median lethal concentrations (LC50) of 28.24×10-3mg Cu2+/L, 21.34 mg Zn2+/L, and 78.74 mg ZnO NP/L. Enhanced acute toxicity was elicited at low concentrations of Cu2+(1.42 to 5.68×10-3mg/L) and ZnO NPs (0.841 mg/L). The interaction of dissolved ions, Cu2+and Zn2+, was discarded as the main source of toxicity towards L. papuana as the mixtures tested followed a concentration-addition pattern that produced~50% mortality (1 toxicity unit [TU] = LC50). Thus, we considered that the enhanced toxicity was mainly caused by the synergistic interaction of ZnO NPs and Cu2+. In contrast, chronic exposure to Cu2+and ZnO NPs significantly inhibited the rotifers rate of population growth only in the groups exposed to the higher concentrations tested, representing about 10-20% of their respective LC50 values. Therefore, reports based only on acute tests might bias the ecological significance of the results as long-term and more complex matrices are required for a better understanding of the potential risks that nanoparticles and co-contaminants represent to the aquatic biota.

Water pollution is one of the most common global problems resulting from increased industrial and agricultural activities. Petroleum hydrocarbons have extremely dangerous to the aquatic environment. The total petroleum hydrocarbon (TPHs) was investigated in water, sediment, and muscles of Coptodon zilliiat Abu Sakhir and Al-Zubair Bridge stations seasonally in the Shatt al-Basra Canal. The results showed a variation in the TPHs levels in the studied stations. In addition, a significant difference in the TPHs was recorded during the seasons in the water, and sediments between stations. The results showed significant differences in the TPHs in the muscles in the spring but no significant in other seasons between the two stations. The results of the lipid contents of fish revealed significant differences between the two studied stations in the fall, spring, and summer seasons but not significant in winter

Macrobenthos are indicators of the physical and chemical changes in aquatic ecosystems. In this research, the diversity of macrobenthoscommunities in the Ortkand River, Iran, was investigated during four consecutive seasons using the Shannon-Weiner, EPT richness indices, and the Hilsenhoff index for water quality at four sampling stations. In addition, sampling of Nemoura cinerea(Arthropoda, Nemouridae) was done to comparemorphological differencesbetween specimens from two upstream and downstream sites using a geometric morphometric approach. The physicochemical parameters of water were also recorded. The entry of fish farm wastewater significantly affects biotic and abiotic environmental factors according to the Shannon-Weiner and Hilsenhoff indices. The results showed a significant positive correlation between DO and Shannon-Wiener index, TDS and the Hilsenhoff index, and DO and EPT richness index. A significant negative correlation was observed between BOD and the Shannon-Wiener index, DO and Hilsenhoff index, and between BOD and EPT richness index. Geometric morphometrics analyses revealed that the two groups differed mainly in pronotum and metanotum morphology. According to the results, monitoring of macrobenthos can help assess rivers’ water quality, and N. cinerea can bea proper bioindicator.

Groupers are the main component of commercial fisheries in the Red Sea. The reproductive biology of Epinephelus tauvinaand Cephalopholis miniatacollected at the Shalatien landing site in the southern Egyptian Red Sea were investigated from January to December 2017. A total of 212 specimens of E. tauvinawith a total length range of 23.6 to 70.3 cm and 243 specimens of C. miniatawith a total length range of 17.4 to 42.1 cm were examined. Females of E. tauvinaand C. miniata accounted for 61.7 and 61.9% of the total fish sampled, showing a 1:1.61 and 1:1.63 male-to-female sex ratio, respectively. The monthly distribution of maturity stages and gonadosomatic index values showed that the spawning season for both sexes was extended from April to October for E. tauvinaand from April to September for C. miniata. The lengths at first sexual maturity of the males and females of E. tauvinawere estimated at 49 and 48.1 cm, respectively, whilethose for C. miniatawere estimated at 23.2 and 22.7 cm, respectively. All our results can help in the proper management of these valuable resources

Cyanobacteria are photoautotrophic bacteria that can adapt to various environments due to their extensive physiological adaptability. These bacteria are naturally distributed in diverse ecosystems, includingfreshwater, marshes, groundwater, lakes, brackish water (estuaries), salt water, moist soils, and dry land. This study was conducted to enlist cyanobacteria isolates in different waterbodies in Mosul, Iraq.For this purpose, 16 sites were selected and sampled. Based on the results, the Gloeocapsa nigrescens was the dominant species (10.34%), followed byMicrocystis robusta (6.69%),Oscillatoria nigro-viridis (6.69%), andOscillatoria sp. (6.69%).Mosul Dam Lake (station 12) was the most diverse one with six cyanobacteria species, including Schizothrixsp., Aphanocapsa koordesii, G. crepidium, O.trichoides, M. flos-aquae, and Plectonema tomasinianum.