Glass Tank Research Articles

Performance of Different Biomaterials as Carbon Sources on the Immunological Response and Oxidative Status of African Catfish Clarias gariepinus in Biofloc Systems

A trial was performed to investigate how carbon sources can affect the welfare status of African catfish (3.8±0.2g and 8±0.11 cm) juveniles in biofloc systems. Inocula was prepared in glass tanks (5L) by adding 20g of pond bottom soil in well aerated water (1L) containing 10mg L-1 ammonium sulphate (NH)4SO4 and 400mg L-1 of four different carbon sources (tapioca, wheat offal, brewery and cassava peel) for 24 hours. Each treatment group (carbon sources and control) were replicated and each tank contained 1000 Clarias gariepinus juvenile, fed with commercial feed (Crude protein 42%) at 5% of their body weight 72 days. The water quality showed that all water parameters remained at concentrations suitable for Clarias gariepinus culture in the studied systems. The enzymes activities were noticed to be different across the biofloc and the selected organs. There were significant differences in serological content in fish between the treatment’s groups (P<0.05). The significant difference was found between the treatments in case of enzymes activity (P<0.05). The study shows that the welfare status with reference to digestive enzymes activity, oxidative status and extent of the immune system stimulation in BFT system is carbon source dependent.

Effects of feeding rate and sediment depth on the survival, growth performance, and biomass of mud polychaete Marphysa iloiloensis from early juvenile to adult in grow-out tanks

Polychaete aquaculture has progressed in some countries to meet the high demand of fish bait and aquaculture industries. However, knowledge on the aquaculture requirements of polychaetes in the grow-out is still scarce. The present study aimed to determine the optimal feeding rate (FR) and sediment depth (SD) for the grow-out culture of mud polychaete Marphysa iloiloensis from early juvenile to adult stage. The effects of two FRs (50 and 100 g m−2) with three different levels of SD (2, 3, and 5 cm) on M. iloiloensis survival, growth performance, and biomass were evaluated. The study was performed in a 2 × 3 factorial experiment using completely randomized design with four replicates per treatment that lasted 120 days. Early juveniles (30 days old) were stocked in glass tanks at 1000 individuals m−2 and grown for 120 days (herein refer as ‘adult’, with musculature and capable of reproduction). Regardless of FR, M. iloiloensis had the highest survival of 45 ± 2% in 5 cm SD but statistically comparable to 3 cm SD (34 ± 5%), while survival was significantly lowest in 7 cm SD (26 ± 3%). The levels of nitrite (NO2) and total ammonia nitrogen (TAN) was significantly higher in the rearing water of 100 g m−2 FR than in 50 g m−2 FR. Higher FR resulted to poor water quality and appeared to contribute to the low M. iloiloensis survival in 100 g m−2 FR. Growth performance was similar among treatments. There was a significant interaction between FR and SD on M. iloiloensis biomass (p < 0.05). In 50 g m−2 FR, no difference was observed in the different levels of SD while in 100 g m−2 FR, biomass was significantly higher in 5 cm SD than in 7 cm SD (p < 0.05). M. iloiloensis biomass in 50 g m−2 FR was higher compared to 100 g m−2 FR, regardless of the SD. Overall, the culture of M. iloiloensis using 50 g m−2 FR in 3–5 cm SD showed the best survival and biomass. Based on these findings, it is recommended that the grow-out culture of M. iloiloensis from early juvenile to adult should follow the 50 g m−2 FR and should be done in tanks with 3–5 cm SD to improve production.

Effect of The Type of Solvent in Azolla Extracts Added to The Ratio on The Growth of Common Carp Cyprinus Carpio L

The study was conducted in the fisheries laboratory of the Department of Animal Production in the College of Agriculture and Forestry/the University of Mosul. The experiment included feeding common carp fish using ten experimental diets containing azalea plant extract in proportions (0.5, 1, 1.5%) of each solvent, ether, acetone, and ethanol, and the control was free of additives. Glass tanks were used in the growth experiment of carp fish for a period of 49 days. The results of the statistical analysis of the final weight values, total and daily weight gain (gm/fish), and the relative and qualitative growth rate % showed that there were significant differences (P≤ 0.05) for the experimental treatments, and the third treatment (ether 1%) was significant compared to the rest of the treatments. While the results of the analysis of the amount of food consumed and the ratio of food efficiency in the presence.

The optimum dose and period of 17α-methyltestosterone immersion on masculinization of red tilapia (Oreochromis spp.)

This study was carried out to examine the effect of combining factors for immersion technique on masculinization of red tilapia (Oreochromis spp.). Three selected doses (1000, 1,500, and 2000 μg/L) of 17α-methyltestosterone (17 MT) immersion, 2 exposure times (3 and 6 h) once or twice a week, and interaction of these factors were tested. A total of 12 treatment combinations under 3 × 2 × 2 factorial experiments in randomized complete block design were conducted to compare with the negative control group (no 17 MT-treated) and positive control group (17 MT-treated feed administration). One hundred red tilapia larvae (14 days post-hatch) were randomly allocated in each treatment and were operated in a 10-L glass jar for 21 days. At the end of the treatment regime, the survival rate was determined. Then, fish were raised in a 150-L glass tank using normal commercial feed for 2 months and sex ratios were determined via the gonad squash technique. None of the immersion treatments tested resulted in a statistically significant (p > 0.05) decrease in survival rate. All 17 MT-treated groups produced progenies with a significantly higher (p < 0.001) proportion of males than the predicted 1:1 sex ratio. Influences of some factor combinations in the masculinization of red tilapia were observed. The male ratio was significantly affected by the dose-period and dose-frequency treatments (p < 0.05). The highest male proportion (95.33% ± 0.58%) was recorded at 1000 μg/L of 17 MT for 6 h once a week which was significantly higher (p < 0.05) than other groups. The production cost of the best group was the cheapest (THB0.0066/fish) and decreased from the traditional procedure by about 10.81%. Therefore, this technique could be implemented for decreasing cost and operating process in commercial tilapia farms.

Improving Keeping for Octopuses by Testing Different Escape-Proof Designs on Tanks for “Big Blue Octopus” (Octopus cyanea)

Octopus cyanea has a wide range of natural distribution and is interesting for scientific research. However, unlike Octopus vulgaris, the species is poorly studied, and few data exist on best practices for keeping them. One of the most common reasons for losing octopuses in human care is their ability to escape from holding tanks. Adult Octopus cyanea (n = 33) were locally collected in Okinawa throughout the year. All animals were housed at the laboratory facilities at the Marine Station of the Okinawa institute of Science and Technology. Animals were kept in a flow-through saltwater system in three different types of holding tanks ranging from 550 L to 600 L tanks or in 2000 L tanks, all with an environment enriched with clay pots or natural rocks as dens. They were fed a daily diet of dead fish or live or dead crustaceans ad libitum. To characterize the effectiveness of different keeping conditions, we compared escape attempts and non-natural deaths during the animals’ time under human care. We found that two types of tanks, the 600 L transparent acrylic glass tanks with weighted lids and the 2000 L tanks with synthetic grass lined walls, had significantly fewer escapes than the 550 L tanks.

Effect of adding phytase enzyme and formic acid to diets of common carp Cyprinus carpio L. on coefficient of digestibility and growth rates.

The study aimed to add phytase enzyme and formic acid at different percentages of control (0) and (1, 2, 3)% in the diets of common carp Cyprinus carpio L.to know their effect on the total digestibility coefficient and growth rates of fish.Common carp fish were used at weight rates of 230±1.53 g/fish, which were randomly distributed in (40×60×40) cm3 glass tanks equipped with aeration and air filtration system and in controlled laboratory conditions. The results showed significant differences (P≤0.05) between treatments and there was a decrease in the coefficient of digestion of protein, fat, carbohydrates and ash for the control treatment T1 compared to all experimental treatments and it amounted to (60.54, 70.39, 32.95, 51.84), respectively. The two treatments T2 and T3 excelled in the coefficient of protein digestion, reaching (85.22 and 86.63), respectively, while no significant differences were recorded between treatments T3, T4, T5, T6, and T7 in the coefficient of fat digestion, and the coefficient of carbohydrate digestion increased (71.43, 74.94, 67.23, respectively, and the ash digestibility factor (84.28, 89.63, 79.21), respectively, for each of the treatments T2, T3, T4.The T1 control treatment recorded the lowest results in weight gain rates of 46.71 g, daily growth rate of 0.57 g/day, relative growth rate of 19.36%, specific growth rate of 0.12 g/day, and food conversion efficiency of 21.19% compared to the experimental treatments, and T3 treatment significantly outperformed the rest of the treatments in daily growth rates. 1.73 g/day, and the relative growth rate and feed conversion efficiency were increased for T3 and T4 treatments.We conclude from this research that it is possible to use diets supplemented with phytase enzyme and formic acid with 1%, 2% and 3% acid as a source of animal protein in the diets of common carp without negative effects on digestion and growth rates.

Validation of a coupled 3D CFD simulation model for an oxy-fuel cross-fired glass melting furnace with electric boosting

Glass furnaces represent a continuous challenge for CFD simulations, which is attributed to the complex description of multiple phases: the turbulent gas phase, raw materials from a solid glass batch and the laminar liquid phase of the glass melt. Prevalence of unsuitable oxy-fuel combustion models, like the eddy-dissipation model, and the lack of advanced coupling methods for the coupling of combustion chamber and glass tank domains have been identified as research gaps in glass furnace simulations. These are tackled in a 3D CFD simulation model for an oxy-fuel glass furnace with electric boosting by introducing two significant improvements compared to previous approaches: (1) The partially-premixed steady diffusion flamelet model in combination with a skeletal25 reaction mechanism was used for combustion modelling. (2) An advanced iterative coupled simulation method is presented, which introduces damping of the solution and a rigorous termination condition. By employing the presented models, the respective temperatures in the combustion chamber and the glass tank were predicted within less than 1.93% and 3.81% of the experimental data.

Modulation of growth, skin mucus and serum immunities, and disease resistance of Nile tilapia fed host‐associated probiotic (Lactobacillus paracasei l61‐27b)

The experiment was performed to examine the effect of Lactobacillus paracasei l61-27b (LP) isolated from Nile tilapia intestine on the growth rate, skin mucus and serum immune parameters and disease resistance. Fish (25.40 ± 0.33 g) were distributed into glass tank (150 litres tank−1) at 20 fish tank−1 and fed with different levels of dietary L. paracasei l61-27b: 0 (LP1), 106 (LP2), 107 (LP3), 108 (LP4) and 109 CFU mL−1 (LP5) for 8 weeks. The results indicated that SGR, WG and FW significantly improved, while FCR significantly decreased, in fish fed LP supplemented. Dietary L. paracasei significantly increased SMLA and SMPA with the highest values recorded for fish in LP4 and LP5 groups. Similarly, SL, SP, ACH50, PI and RB were significantly stimulated in fish fed LP diet compared with fish fed control diet. Challenge study showed that in comparison with the control diet (20% survival), the survival rates of fish fed the L. paracasei were significantly (p < 0.05) higher; by 63.33% (LP2), 66.67% (LP3), 80.00% (LP4) and 83.33% for LP5. The relative per cent survival (RSP) was 54.17%, 58.33%, 75% and 79.17% in LP2, LP3, LP4 and LP5, respectively. In conclusion, the dietary inclusion of L. paracasei can be potentially used in Nile tilapia to improve its growth and health status.

Effects of Carbohydrate and Artificial Substrate Integration on Growth Performance of Mudskipper (Pseudapocryptes elongatus)

The carbon and artificial substrate integration was applied in mudskipper (Pseudapocryptes elongatus) culture to evaluate its effect on growth and enzyme activity. Wild mudskipper fries (6.9–7.3 cm; 3.88–4.12 g) were obtained in the coastal area of the Mekong delta. Fish were reared in 1 m3 fiber glass tanks containing 600 L of 15 ‰ seawater for 60 days in outdoor conditions. Mud was added to the tank bottom around 15 cm to simulate the culture condition as would be found in an earthen pond. Molasses (38% Carbon) was added daily to the culture water based on TAN level to balance C/N to 10. The results showed that the survival was in the range of 80.6–85%, and no significance in term of survival was found when comparing treatments. The individual weight of fish was 11.93–14.11 g/ind in range, fish in the culture where carbon and both carbon and substrate addition had significantly better growth and productivity than fish in the culture where molasses and substrates were not applied. The results of this study demonstrate that the growth performance and production of mudskipper significantly increased when the biofloc and substrate integration was applied.

Influence of light, water motion, and stocking density on the growth and pigment content of Halymenia durvillei (Rhodophyceae) under laboratory conditions

The tropical red seaweed Halymenia durvillei Bory de Saint Vincent is a potential source of the high-value pigments, r-phycoerythrin (RPE) and r-phycocyanin (RPC). The unique properties of these pigments find many applications—from food to cosmetics, pharmaceuticals, and biomedical research. This study aimed to improve the land-based culture technology of H. durvillei by determining the appropriate combination of light, water motion, and stocking density that would result in high growth performance and high RPE and RPC content. Combinations of two light levels (full light, 100% and reduced light, 67%), two water motion levels (low and moderate), and three stocking densities (50, 100, and 200 g) were studied using 64.5-L glass tanks with flow-through seawater and aeration systems at the outdoor land-based seaweed nursery in Bolinao, Pangasinan, Philippines. After 6 weeks of culture, growth performance (growth rate and productivity) of H. durvillei and phycobiliprotein content were best under a combination of full light (100%), moderate water motion, and 50-g stocking density. The generally low light regime during the experimental period, which coincided with the cold, dry season characterized by shorter days and overcast skies, may have influenced H. durvillei to maximize the use of available resources such as light and possible increased nutrient availability from water motion to promote growth and phycobiliprotein synthesis. Treatments with low stocking densities generally showed satisfactory growth and phycobiliprotein content. This study provides groundwork for future research into mechanisms by which these and other factors affect the growth and physiology of H. durvillei in culture.

Incoherent imaging through highly nonstatic and optically thick turbid media based on neural network

Imaging through nonstatic scattering media is one of the major challenges in optics, and encountered in imaging through dense fog, turbid water, and many other situations. Here, we propose a method to achieve single-shot incoherent imaging through highly nonstatic and optically thick turbid media by using an end-to-end deep neural network. In this study, we use fat emulsion suspensions in a glass tank as a turbid medium and an additional incoherent light to introduce strong interference noise. We calibrate that the optical thickness of the tank of turbid media is as high as 16, and the signal-to-interference ratio is as low as − 17 dB . Experimental results show that the proposed learning-based approach can reconstruct the object image with high fidelity in this severe environment.

Effects of diazinon on olfactory epithelium and genes related to olfactory signal transduction in Caspian roach, Rutilus caspicus

Olfaction in fishes is biologically-essential chemoreceptors. It provokes important behaviors for the survival of fish such as feeding, reproduction, avoiding predator and intraspecific communication. Pesticides can affect the olfactory epithelium and genes related to olfactory transduction and impair olfactory function. The present study aims to determine how toxicity of diazinon impacts olfaction of Caspian roach, Rutilus caspicus in histological and gene levels. We exposed fish (0.7 ± 0.05 g in weight) to 0, 1, 2 and 3 mg L-1 diazinon (60 fish in each 3- replicate 60-L glass tank) for 7 days in freshwater. Diazinon concentrations were chosen based on reports on its concentration in surface waters. Mortality rate, histological events of olfactory epithelium, and genes expression at the 7th day after diazinon exposure included a significant decrease in the number of olfactory receptor cells (ORCs), while increased goblet cells (GCs). In addition, G­protein αi (Gpαi) was significantly upregulated, whereas calmodulin-dependent kinase II α (CaMKIIα) was significantly downregulated after 7 days as compared to the control group. These results indicate that diazinon can impair olfactory function through effect on the olfactory epithelium and olfactory signal transduction pathways in the Caspian roach fingerlings.

KESETIMBANGAN ADSORPSI LOGAM BERA T (Zn) DENGAN ADSORBEN PASIR YANG DILAPISI BESI OKSIDA

Sorption to iron-oxide coated sand is a promising technology for removal of dissolved heavy metal fraction in aqueous solution waste industry due to the availability this material in Indonesia and economic considerations. The objective of this experiment was to study the effect of temperature upon equilibrium constant using lsoterm Langmuir adsorption model and lsoterm Freundlich adsorption model. This experiment was started by determining equilibrium time as a basic time running this experiment. Adsorption experiment was conducted at stirred glass tank by making 5 mg!L ZnCl2 solutions. This solution was added with iron oxide coated sand as adsorbent. A few minutes before equilibrium time, sample was drawn and the remaining concentration was measured by AAS. The results showed that the adsorption temperature had significant effect to adsorption Zn2+onto iron oxide coated sand as adsorbent. The effect of temperature upon equilibrium constant using lsoterm Langmuir model followed the equation b [-831.41] = 0.22452exp T with relative error 6.98%. The effect of temperature upon equilibrium constant using lsoterm Freundlich model followed the equation kF = 0.05797 1 exp (-0. 003 T) and n = 3 with relative errors respectively 6. 57% and 4. 52%.

The Roland von Glasow Air-Sea-Ice Chamber (RvG-ASIC): an experimental facility for studying ocean–sea-ice–atmosphere interactions

Abstract. Sea ice is difficult, expensive, and potentially dangerous to observe in nature. The remoteness of the Arctic Ocean and Southern Ocean complicates sampling logistics, while the heterogeneous nature of sea ice and rapidly changing environmental conditions present challenges for conducting process studies. Here, we describe the Roland von Glasow Air-Sea-Ice Chamber (RvG-ASIC), a laboratory facility designed to reproduce polar processes and overcome some of these challenges. The RvG-ASIC is an open-topped 3.5 m3 glass tank housed in a cold room (temperature range: −55 to +30 ∘C). The RvG-ASIC is equipped with a wide suite of instruments for ocean, sea ice, and atmospheric measurements, as well as visible and UV lighting. The infrastructure, available instruments, and typical experimental protocols are described. To characterise some of the technical capabilities of our facility, we have quantified the timescale over which our chamber exchanges gas with the outside, τl=(0.66±0.07) d, and the mixing rate of our experimental ocean, τm=(4.2±0.1) min. Characterising our light field, we show that the light intensity across the tank varies by less than 10 % near the centre of the tank but drops to as low as 60 % of the maximum intensity in one corner. The temperature sensitivity of our light sources over the 400 to 700 nm range (PAR) is (0.028±0.003) W m−2 ∘C−1, with a maximum irradiance of 26.4 W m−2 at 0 ∘C; over the 320 to 380 nm range, it is (0.16±0.1) W m−2 ∘C−1, with a maximum irradiance of 5.6 W m−2 at 0 ∘C. We also present results characterising our experimental sea ice. The extinction coefficient for PAR varies from 3.7 to 6.1 m−1 when calculated from irradiance measurements exterior to the sea ice and from 4.4 to 6.2 m−1 when calculated from irradiance measurements within the sea ice. The bulk salinity of our experimental sea ice is measured using three techniques, modelled using a halo-dynamic one-dimensional (1D) gravity drainage model, and calculated from a salt and mass budget. The growth rate of our sea ice is between 2 and 4 cm d−1 for air temperatures of (-9.2±0.9) ∘C and (-26.6±0.9) ∘C. The PAR extinction coefficients, vertically integrated bulk salinities, and growth rates all lie within the range of previously reported comparable values for first-year sea ice. The vertically integrated bulk salinity and growth rates can be reproduced well by a 1D model. Taken together, the similarities between our laboratory sea ice and observations in nature, as well as our ability to reproduce our results with a model, give us confidence that sea ice grown in the RvG-ASIC is a good representation of natural sea ice.

Banana stem addition during transportation reduces the mortality of African catfish Clarias gariepinus

In order to lower the fish mortality during transportation, the chopped banana stem (BS) was added during the African catfish transport procedure. The fish were packed in plastic bags with a density of 100 fish in 1.5 L water. The chopped BS was added into the plastic bags with different concentrations: 0 (control), 5, 10, and 15 mg L−1. The fish were transported for 5 hours. After transportation, the fish, together with the added chopped BS, were distributed into glass tanks and acclimated for 24 h. After 24 h, the results showed that the BS treatments had lower cumulative mortality compared to the control with the lowest mortality was observed at the 15 mg L−1 concentration (p<0.05). The BS treatments also increased the antioxidant defence and the immune status of the fish thus might be responsible for the reduced mortality.

Novel effective mosquito larvicide DL-methionine: Lack of toxicity to non-target aquatic organisms

Mosquito larvicides are an effective tool for reducing numbers of adult females that bite and potentially spread pathogenic organisms. Methionine, an essential amino acid in humans, has been previously demonstrated to be a highly effective larvicide against four (4) mosquito species in three (3) genera, Anopheles, Culex and Aedes. The aim of the present study was to determine the potential impact on non-target aquatic organisms of methionine applied as a mosquito larvicide. DL-methionine concentrations ranging from 0.06% to 1.00% were used; wherein the highest concentration of 1.00% would result in 100% mortality within 48 h in mosquitoes. Acute toxicity assays were conducted in accordance with the US Environmental Protection Agency (US EPA) guidelines for the water flea (Daphnia magna Straus; Cladocera: Daphniidae) and the fathead minnow (Pimephales promelas Rafinesque; Cypriniformes: Cyprinidae). Water fleas and fish were placed directly into the solutions in glass containers and tanks for 48-hours and 96-hours, respectively. When applied within the above-mentioned range of effective mosquito larvicide concentrations, DL-methionine meets US EPA criteria as a "practically non-toxic" pesticide for both species. These results suggest that methionine is a viable alternative to current mosquito larvicide options, which are typically classified as moderately to highly toxic and may be a valuable addition to a mosquito integrated pest management program.

Compound analysis of gas bubble trajectories with help of multifractal algorithm

Three-dimensional trajectories of gas bubbles were the subject of study in this article. Authors carried out experiments in two glass tanks with dimensions of 300 × 300 × 1500 mm and 300 × 150 × 500 mm, respectively, filled with distilled water with a temperature equal to T = 21 ± 1 °C. The tests were carried out for an air volume flow rate, values from 0.00492 l/min to 0.0645 l/min. Basic characteristics of recorded measurement data like: analysis of the bubble detachment frequency from the nozzle, gas bubble size analysis have been shown. Based on the conclusions from those characteristics the multifractal algorithm analysis has been presented as one that allows comprehensive analysis of such a process. The results as a comparison of the main points on the air volume flow rate showed that: the trajectories of gas bubbles in liquid are multifractal and the width of the multifractal spectrum, and thus the complexity of the process being examined, depends on the air flow, the diameter of the bubble generating nozzle and the height of the liquid column in which the phenomenon is examined. The results of the analysis show that the key impact on the overall observed phenomenon is the deformation of the bubble surface, oscillation of the bubble column and observation of the two-phase flow spatially (three-dimensional).

Potential role of L-ascorbic acid with Field cricket (Gryllus bimaculatus) meal in diets of Nile Tilapia (Oreochromis niloticus) during sex reversal and nursing

A synthetic androgen 17-α methyltestosterone (MT) commonly used in the production of mono-sex fry of Nile tilapia (Oreochromis niloticus) during the first 21 days for sex reversal has been considered to suppress immunity thereby reduce survival. Present trial was conducted to evaluate whether vitamin C (L-ascorbic acid, AA) supplementation would benefit in terms of survival, growth, and stress resistance. Nile tilapia fry were fed with isonitrogenous (57.8±0.2% CP) diets formulated using Field cricket (Gryllus bimaculatus) meal (approx. 79%) and fish meal (approx. 20%) to use as control, and five other diets were prepared by supplementing 10, 20, 30 40 and 50 g of vitamin C (L-ascorbic acid per kg diet). Eighteen aquaria or glass tanks (100 L) were used having three replicates per treatment. Each aquarium was stocked with 300 fish (0.01±0.00 g). Fry were nursed for another 91 days to check their sex-ratio. Gonad histology showed increased number of spermatogonia when L-ascorbic dose was 30g/kg diet. At the end of the feeding trial results indicated significant increase (P&lt;0.05) in growth, feed utilization and survival when fed with vitamin C at the dose of 10 g/kg diet during sex-reversal and nursing periods as compared to the control. Similarly, hematological information also showed 10 g vitamin C dose per kg diet. Polynomial regression showed that the optimum dietary ascorbic acid doses were calculated at 15.9, 10.0 and 12.0 g AA per kg diet for highest survival (83.5% max), weight gain and SGR, respectively, but the doses higher than 20 g of L-ascorbic acid/kg diet was not beneficial. Highest apparent digestibility (AD%) of protein (84.1%) was at 15.37g and AD% of lipid (91.4% max) was 17.8g of vitamin C/kg diet. Salinity challenge test also showed highest survival can be achieved at 15.8 g AA per kg diet. As the survival of fry is the most important parameter at these stages, the dose which resulted highest survival i.e., 15 g/kg diet is recommended.

Study on the impacts of chemical and green synthesized (Leucas aspera and oxy-cyclodextrin complex) dietary zinc oxide nanoparticles in Nile tilapia (Oreochromis niloticus)

The present study was designed to evaluate the health effects of dietary nanozinc prepared by two methods: conventional chemical method and green method. The parameters evaluated were the extent of bioaccumulation, antioxidant status, histological, immunological changes and DNA damage in Nile tilapia fed nanozinc feed. Zinc oxide nanoparticles were first prepared by green and chemical methods. Before feed preparation, the in vitro antioxidant activity and antibacterial activity of both types of nanoparticle solutions were tested and the results revealed enhanced activities in green synthesized ZnO NP solution. After the acclimatization period, 420 Nile tilapias were distributed randomly into 21 glass tanks with 20 fish per tank in triplicates. Fish were fed control diet without any ZnO NP and (i) GT1—green synthesized ZnO NP diet at 100 mg/kg, (ii) CT1—chemically synthesized ZnO NP diet at 100 mg/kg, (iii) GT2—green synthesized ZnO NP diet at 200 mg/kg, (iv) CT2—chemically synthesized ZnO NP diet at 200 mg/kg, (v) GT3—green synthesized ZnO NP diet at 400 mg/kg and (vi) CT3—chemically synthesized ZnO NP diet at 400 mg/kg for 60 days. After 60 days, gill and liver samples were collected for analysing oxidative stress, histopathological alterations and bioaccumulation of zinc, whereas serum samples were collected for evaluating immune response. The results revealed that the GT3 diet significantly (P < 0.05) enhanced the level of antioxidant enzymes (CAT, SOD, GPx, GR and GSH) than dietary nanozinc prepared by the chemical method. Similarly, the innate immunological parameters were significantly (P < 0.05) augmented in fish fed GT3 diet. Comparative histological study of liver and gill tissues revealed normal architecture in the tissues of fish fed green synthesized NP–enriched feed, whereas the tissues of fish fed chemically synthesized NP feed exhibited histological alterations. Bioaccumulation of zinc was more in the liver followed by the muscle and least in the gills and DNA damage was more evident in fish fed chemically synthesized ZnO NP–enriched feed. In conclusion, the results suggest that the inclusion of 400 mg/kg GT3 diet in fish diet enhanced the level of antioxidant enzymes, boosted immune response and did not cause histological damage to organs, and therefore, GT3 nanofeed can be recommended for fish health improvement.

Microbial Contamination of Diesel-Biodiesel Blends in Storage Tank; An Analysis of Colony Morphology

Fuel contamination is a major issue that comes with the utilization of biodiesel. Microbial growth is one of the primary causes of contamination during fuel handling and storage. This work attempts to identify the types, shapes, and growth profiles of microorganisms on fuel samples. The morphology of microbial colonies presented in order to analyze the potential of fuel contamination. The diesel, biodiesel, and the blends are stored in stainless steel (SS) and glass tanks, where each is placed indoors and outdoors during the 90 days of storage time. The morphology of microbial colonies is observed through a microscope with a magnification of 1000x and the quantity is calculated by a digital colony counter. Microbial contamination in all samples considered as high contamination where the Colony Forming Unit (CFU) is greater than 105 L-1. Colony forms are far more assorted in blends than in pure diesel (B0) and neat biodiesel (B100). The transformation of microbial colonies accelerates after 60 days of storage time. The results reveal that the number of bacterial colonies that grow in B20 is higher and more varied, nevertheless the contamination in B100 is significantly higher. This is indicated by a 1.5-fold rise in B20 acidity and a 2.5-fold increase in water content compared to the initial condition.