Red Nile Research Articles

Nile red staining of polyethylene and polystyrene in Daphnia magna tests

Microplastics pollution represents a stringent global issue. Their accumulation in the aquatic environment remains complicated due to the abundance, distribution, and resulting environmental effects they induce. Recently, assessing the toxicity level of aquatic organisms has gained scientific interest. Due to the diverse types and sizes of polymers present in the environment, the detection and evaluation of their effects are still a challenging issue. Polyethylene (PE) and polystyrene (PS) are the most commonly used polymers and are therefore predominantly detected in both marine and freshwater aquatic environments. This paper aims to evaluate the effects of Red Nile-stained PE and PS, tested in different particle sizes (PE 40-48, 125, >125 µm, and PS 20, 200, 430 µm) on Daphnia magna, and highlight them through microscopic analysis. Acute toxicity tests conducted over a 48-hours exposure did not reveal significant toxicity effects in terms of mortalities compared to the controls. Red Nile staining allowed the visualization of the shapes and sizes of the tested microplastics and their entry pathways into the Daphnia bodies. PS of 20 µm size was detected in the digestive tract of Daphnia, indicating as primary pathway of entry into the body of aquatic organisms. No acute toxic effects were recorded as a result of direct exposure to PE and PS particles. However, sub-lethal effects such as feeding and growth disturbances, which could affect organisms in the long term, are suspected.

Introducing of high rich lysine, arginine, and unsaturated fatty acids microalga as a food supplement.

Microalgae are powerful source for nutritionally valuable components as proteins, carbohydrates and especially unsaturated fatty acids. Microalgae may be employed in pharmaceutical, food, cosmetic, health industries, and biofuels. In this study for looking at high-level unsaturated fatty acids species, from 31 strains, by comparing growth curves, the best strain with a high growth rate and lipid content was selected by red Nile staining. It was determined by molecular identification that this strain belongs to the genus Chlorella sp. and is deposited into the Agricultural Biotechnology Research Institute of Iran Culture collection with culture collection number ABRIICC 30,041. Biomass analysis after growth optimization by response surface methodology showed that the selected strain had a specific growth rate of 0.216 ± 0.008 d-1, biomass productivity of 142.58 ± 4.41mg/Ld, and lipid content of 13.9 ± 0.26% with a high level of unsaturated fatty acids of 53.15%. It also included 51.3 ± 0.53% protein with a very high quality essential amino acids of 40.36%, the most lysine (8.77%) and arginine (13.31%) has been reported until now, and 26.9 ± 0.23% carbohydrates in photoautotroph condition. By MTT assay, there is no effect of cytotoxicity. This research introduces a potent native strain comparable with commercial strains that can be a hopeful source for food supplements and valuable bioactive ingredients in functional foods.

Heavy atom effect through chalcogen substitution in Red Nile dye: a theoretical investigation

Heavy atom effect through chalcogen substitution in Red Nile dye: a theoretical investigation

Effectiveness of Collagen Extracted From the Skin of Nile Tilapia Fish (Oreochromis niloticus) to Accelerate Wound Healing in vivo: A Narrative Review

Developing wound dressings with good properties to accelerate wound healing has always been challenging. Mammal collagen is well known as the desired choice among naturally produced dressings despite experiencing major drawbacks. Therefore, researchers have explored the by products of Oreochromis niloticus fish or red Nile tilapia, such as the scales and skin as alternative source of collagen. This narrative review analyzes the effectiveness of collagen extracted from Oreochromis niloticus skin and its beneficial properties to accelerate wound healing in vivo. Recent studies were compiled to provide a compact review on the effectiveness of the collagen in hastening wound healing process. Faster wound closure with upregulation of multiple growth factors, and high hydroxyproline content are some of the findings. The collagen extract could also promote the formation of epidermal layers, fibroblasts proliferation, and dermal reconstitution. Thus, Oreochromis niloticus skin collagen extract has the potential to be developed as an effective wound dressing.

Evaluation of dietary coffee Coffee canephora husk supplementation on the growth, blood chemicals, and antioxidative activity of red Nile tilapia Oreochromis sp.

Coffee by-products can be used as a feed additive for red Nile tilapia. This study aimed to evaluate the utilization of different dietary coffee husk supplementation dosages on the growth and antioxidative activity of red Nile tilapia (Oreochromis sp.). This study was designed following the completely randomized design experimental method, containing five dietary supplementation treatments, namely P0 (control, 0%), P1 (1%), P2 (2%), P3 (3%), and P4 (4%). Fish were reared for 8 weeks and fed three times a day. Parameters observed contained growth performance and antioxidative activity. The results showed that dietary coffee husk powder supplementation treatments provide higher growth than control treatment. Based on blood chemicals, coffee husk-supplemented diets could enhance the HDL content and reduce cholesterol, triglycerides, and LDL (P<0.05). Superoxide dismutase enzyme was also found higher in coffee husk supplemented diets than in control diet (P<0.05). The MDA level decreased on the coffee husk-supplemented diet treatment and was lower than the control treatment (P<0.05). Dietary supplementation of coffee husk could positively affect liver performance, based on hepatosomatic index and glycogen level. This study concludes that 4% coffee husk in the diet is considered the best treatment to improve the growth and antioxidation level of red Nile tilapia. 
 
 Keywords: antioxidant, coffee husk, diet, growth, tilapia
 
 
 ABSTRAK
 
 Coffee by- product dapat digunakan dalam pakan ikan nila sebagai feed additive. Penelitian ini bertujuan untuk mengevaluasi pemanfaatan tepung kulit dengan dosis berbeda terhadap kinerja pertumbuhan dan antioksidan ikan nila merah (Oreochromis sp.). Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap yang terdiri dari lima perlakuan pakan, yaitu P0 (Kontrol), P1 (1%), P2 (2%), P3 (3%) dan P4 (4%). Pemeliharaan dilakukan selama 60 hari dengan frekuensi pemberian pakan sebanyak 3 kali sehari. Parameter yang diamati adalah kinerja pertumbuhan dan antioksidan. Hasil menunjukkan bahwa pemberian tepung kulit kopi dalam pakan memberikan pertumbuhan yang lebih tinggi dari perlakuan kontrol. Profil biokimia darah menunjukkan bahwa penambahan tepung kulit kopi meningkatkan HDL dan menurunkan kolesterol, trigliserida dan LDL pada ikan yang diberi pakan perlakuan yang mengandung kulit kopi lebih tinggi dibandingkan dengan control (P<0,05). Enzim SOD lebih tinggi pada ikan yang diberi pakan perlakuan kulit kopi dibandingkan control (P<0,05). Kadar MDA menurun pada perlakuan penambahan tepung kulit kopi dan lebih rendah dari perlakuan control (P<0,05). Suplementasi tepung kulit kopi berpengaruh positif terhadap kinerja hati yang ditunjukkan pada nilai indeks hepatosomatik dan glikogen hati. Penelitian ini menyimpulkan bahwa, penggunaan tepung kulit sebesar 4% dalam pakan dianggap paling baik dalam meningkatkan kinerja pertumbuhan dan antioksidan pada ikan nila.
 
 Kata kunci: antioksidan, kulit kopi, pakan, pertumbuhan, ikan nila

In vivo application of Oreochromis niloticus scales collagen as alternative wound healing therapy

Fish collagen derived from its skins, scales or bones are known to have many advantages in medical and pharmaceutical applications. This study evaluates the effectiveness of collagen extracted from the scales of local Malaysian Oreochromis niloticus or red Nile tilapia fish, on wound healing in an animal model. 21 male BALB/c mice were divided into three different groups namely the control group, Oreochromis niloticus acid-solubilized collagen extracts treated group; and acriflavine treated group. A full thickness surgical wound of about 1.5 cm were inflicted on the dorsal area of the animal. Treatment with collagen extracts and acriflavine were applied daily on the wounds and measured every day for 9 days. The mice were randomly sacrificed on day 3, 6, and 9, and the skin samples were taken for histological assessment. After 3 days, treatment with collagen extracts and acriflavine recorded an average wound measurement of 7.84±0.32 mm and 7.14±0.32, respectively. On day 9, the progress of wound healing showed significant differences. Mice treated with collagen extracts recorded an average wound measurement of 1.27±0.08 mm, as compared to 3.26±0.05 mm of acriflavine treated, and 3.36±0.18 mm of the control group. The wound assessment showed that collagen extracted from the scales of local Oreochromis niloticus fish produced significant results based on the skin re-epithelialization process and formation of new blood vessels. This finding indicates that collagen extracted from the local Oreochromis niloticus scales possessed effective wound healing properties for surgical wounds as demonstrated on the skin of the animal model.

Effect of Different Cooking Methods on Selenium Content of Fish Commonly Consumed in Thailand.

Although fish are good sources of selenium (Se), an essential trace element for the human body, very limited data exist on Se content in commonly consumed fish in Thailand. Consequently, this study investigated selenium content and the effect of cooking among 10 fish species (5 freshwater and 5 marine) most-commonly consumed by the Thai people. The fish were purchased from three representative wholesale markets within or nearby to Bangkok. All fish species were prepared to determine their edible portions (EP) and moisture contents. Total Se in fresh, boiled, and fried fish were analysed using Inductively Coupled Plasma-Triple Quadrupole-Mass Spectrometry (ICP-QQQ-MS). In general, higher levels of Se were found in marine fish (37.1–198.5 µg/100 g EP in fresh fish, 48.0–154.4 µg/100 g EP in boiled fish, and 52.9–262.4 µg/100 g EP in fried fish) compared to freshwater fish (6.9–29.4 µg/100 g EP in fresh fish, 10.1–26.5 µg/100 g EP in boiled fish, and 13.7–43.8 µg/100 g EP in fried fish). While Longtail tuna showed significantly higher Se content than other fish (p < 0.05), boiled Longtail tuna had significantly lower true retention of Se than the other fish (p < 0.05). Most fish species retained a high level of selenium (ranged 64.1–100.0% true retention in boiling and frying). Longtail tuna, Short-bodied mackerel, Indo-pacific Spanish mackerel, Nile tilapia, and red Nile tilapia–cooked by boiling and frying–are recommended for consumption as excellent sources of selenium.

Effect of miRNA: MRE Complementarity for SBP‐1 Gene Silencing in a Caenorhabditis Elegans Apoptosis Model

Small Interfering RNAs (siRNA) are a type of post‐transcriptional gene regulator with perfect complementarity to its target gene/mRNA. microRNAs (miRNA) are a type of post‐transcriptional gene regulator that silences a number of genes based on sequence complementarity to the miRNA Response Element (MREs) on the target mRNA. siRNAs of varying complementarity to their target sequence will be used as a proxy to [investigate/disprove] the existence of a miRNA complementarity level that maximizes gene silencing of SBP‐1 which regulates lipid homeostasis in C. elegans.The lipid homeostasis and fatty acid synthesis pathway in C. elegans is homologous to the human SREBP pathway. Red Nile staining and body size measurements provide proxy measurements for C. elegans lipid homeostasis and fatty acid synthesis in response to glucose feeding and siRNA introduction via soaking. SBP‐1, fat‐2, fat‐5, fat‐6, fat‐7, and elo‐2 mRNA expression in C. elegans is measured via RT‐PCR.In this study, we determine whether higher siRNA:mRNA complementarity increases siRNA silencing of the Bcl‐2 and Sbp‐1 pathways in C. elegans following the introduction of high and low complementarity siRNAs as a proxy for investigating the gene silencing effects of miRNA:MRE complementarity.

Effects of Different Cooking Methods on the Vitamin D Content of Commonly Consumed Fish in Thailand.

This study determined vitamin D content in commonly consumed fish in Thailand and the effects of different cooking methods on vitamin D retention. Five species of freshwater fish and four species of marine fish were purchased from three representative markets. All of the fish were individually prepared according to common household practices. Vitamin D2 and D3 were determined using the HPLC standard method (AOAC method 995.05). The results indicated that vitamin D3 was the only detectable form of vitamin D in the fish. Vitamin D content of raw freshwater fish ranged from 2.42 to 48.5 µg per 100 g edible portion (EP), which was higher than that of raw marine fish (2.94 to 4.69 µg per 100 g EP). Common silver barb, Red Nile tilapia, and Nile tilapia (freshwater fish living in the limnetic zone) contained high levels of vitamin D (48.5 ± 26.5, 31.0 ± 7.7, and 19.8 ± 3.5 µg per 100 g EP, respectively). Boiled fish (except for Common silver barb), fried fish (except for Striped snakehead, Walking catfish, and Common silver barb), and grilled fish (except for Common silver barb, Giant sea perch, and Short-bodied mackerel) retained high levels of vitamin D, which were not significantly different (p > 0.05) from raw fish. Common silver barb, Red Nile tilapia, and Nile tilapia—cooked by boiling, frying, and grilling—are recommended for consumption as excellent sources of vitamin D.

Utilization of hydrolyzed corncob as a carbohydrate source in diets for red Nile tilapia Oreochromis niloticus

This study was aimed to evaluate the influence of corncob hydrolysis on its crude fiber content, digestibility level, and utilization in the red Nile tilapia diet. This study was performed in two steps, namely hydrolysis and digestibility test. The first study step was enzymatic hydrolysis using 0.4 g/kg cocktail enzyme, followed by chemical hydrolysis using hydrochloric acid (HCl) at different treatments, i.e. concentration, incubation period, and ratio. The second step was designed using a completely randomized design with five treatments, i.e. Rd (reference diet), TJt15% (15% unhydrolyzed corncob), TJt30% (30% unhydrolyzed corncob), TJh15% (15% corncob hydrolysis), and TJh30% (30% corncob hydrolysis). The average weight of tilapia was 15.86 ± 0.19 g/fish. The hydrolyzed corncob meal used for the second study step from the hydrolysis production could reduce 57.53% of crude fiber, 38.15% of NDF fiber fraction, 6.43% of ADF fiber fraction, and 61.96% of hemicellulose. The digestibility test results showed that the hydrolyzed corn cob diet obtained a higher digestibility level, digestive enzyme activity, and blood plasma protein than the unhydrolyzed corncob diet (P&lt;0.05). This study concludes that the corncob hydrolysis eliminates the crude fiber content, fiber fraction contents (NDF, ADF, and hemicellulose), and improves the digestibility level of red Nile tilapia.&#x0D; &#x0D; Keywords: Corn cobs, crude fiber, digestibility, hydrolysis, tilapia.&#x0D; &#x0D; ABSTRAK&#x0D; &#x0D; Penelitian ini bertujuan mengevaluasi pengaruh hidrolisis tongkol jagung terhadap kandungan serat kasar, kecernaan, dan pemanfaatannya dalam pakan ikan nila merah. Penelitian dilakukan dalam dua tahap, yaitu hidrolisis bahan dan uji kecernaan. Penelitian tahap pertama yaitu hidrolisis secara enzimatik menggunakan koktail enzim 0,4 g/kg dan dilanjutkan dengan hidrolisis kimiawi menggunakan asam klorida (HCl) dengan perlakuan yang berbeda yaitu konsentrasi, lama waktu inkubasi, dan rasio. Penelitian tahap kedua dirancang dengan menggunakan rancangan acak lengkap dengan lima perlakuan yaitu Rd, TJt15% (tongkol jagung tidak dihidrolisis 15%), TJt30% (tongkol jagung tidak dihidrolisis 30%), TJh15% (tongkol jagung dihidrolisis 15%), dan TJh30% (tongkol jagung dihidrolisis 30%). Ikan uji dengan bobot rata-rata sebesar 15,86±0,19 g/ekor. Hidrolisis tepung tongkol jagung dengan konsentrasi HCl 0.1 N, lama waktu inkubasi 8 jam, dan dengan rasio 1:4 yang digunakan untuk penelitian selanjutnya. Hidrolisis terhadap tepung tongkol jagung dapat menurunkan serat kasar 57,53%, fraksi serat NDF 38,15%, ADF 6,43%, dan hemiselulosa 61,96%. Hasil penelitian uji kecernaan menunjukkan bahwan pakan yang mengandung tongkol jagung terhidrolisis menghasilkan nilai kecernaan, aktivitas enzim pencernaan dan protein plasma darah yang lebih tinggi dibandingkan dengan yang tidak dihidrolisis (P&lt;0.05). Kesimpulanya, hidrolisis tongkol jagung menggunakan asam klorida (HCl) 0,1 N, lama waktu inkubasi 8 jam, dan rasio 1:4 dapat menurunkan serat kasar, fraksi serat (NDF, ADF, dan hemiselulosa), serta meningkatkan nilai kecernaan pakan ikan nila merah.&#x0D; &#x0D; Kata kunci : Hidrolisis, kecernaan, nila, serat kasar, tongkol jagung

Analysis of fluctuating asymmetry of black strain tilapia oreochromis niloticus and red strain tilapia Oreochromis niloticus in Kabat Fish Hatchery Center Banyuwangi, East Java

Fluctuating asymmetry of bilateral meristic traits is one of the simple methods to calculate phenotype variation and discover the stability of fish development. The aims of this research are analyzing quantitative information about the level of asymmetry of Black Nile Tilapia and Red Nile Tilapia in Kabat Banyuwangi Fish Hatchery Center (BBI) as reference breeding program at Kabat Banyuwangi Fish Hatchery Center. The length of Black Nile Tilapia and Red Nile Tilapia was 50 – 150 gram with 100 samples of fish for each strain so the total is 200 samples of fish. Bilateral meristic traits that have been observed was the number of soft pectoral fins, the number of soft ventral fins, the number of scales on the lateral line, and the first-gill filter of Nile Tilapia. The results show that the highest value of the fluctuating asymmetry of number (FAn) and the fluctuating asymmetry of magnitude (FAm) are 0.65 and 1.38 for Black Nile Tilapia and 0.6 and 1.04 for Red Nile Tilapia. However, the lowest value of FAn and FAm are in soft ventral fins which are 0.22 and 0.22 for Black Nile Tilapia and 0.37 and 0.37 for Red Nile Tilapia.

Acute-lethal toxicity test on juvenile Oreochromis niloticus exposed to Piper betle extract under static exposure

Purpose This study aims to evaluate the effect of Piper betle leaf extract towards the acute-lethal toxicity, LC50 of red Nile tilapia juveniles (Oreochromis niloticus). Design/methodology/approach Ten red Nile tilapia juveniles per tank (in triplicate) were used as an experimental fish for the LC50 bioassay. Five different concentrations of P. betle extract; 80 ppm, 90 ppm, 100 ppm, 110 ppm and 120 ppm, were tested on the red Nile tilapia juveniles and one tank was acting as a control. The progress of the LC50 and lethal time of fish mortality were observed and recorded within the random interval of 96 h. The value for LC50 was determined as 100 ppm of P. betle leaf extract. Higher number of fish mortalities was observed when concentration higher than 100 ppm was tested on to the red Nile tilapia juveniles. Findings Data obtained shows that the P. betle concentration of 120 ppm accelerated the fish mortality period. Originality/value However, adaption of P. betle extract occurred after 50 h, as there was no fish mortality observed within the time.

Isolation and characterization of Botryococcus braunii from a freshwater environment in Tenggarong, Kutai Kartanegara, Indonesia

Abstract. Nugroho RA, Subagyono DJN, Arung ET. 2020. Isolation and characterization of Botryococcus braunii from a freshwater environment in Tenggarong, Kutai Kartanegara, Indonesia. Biodiversitas 21: 2331-2336. The use of microalgae as an alternative source of oil has gained much attention in recent years. The present study was conducted to isolate and characterize microalgae Botryococcus braunii from a freshwater environment, located in Tenggarong, Kutai Kartanegara, East Kalimantan, Indonesia. B. braunii were cultured and determined their growth in terms of biomass yield and the presence of lipid globules by red Nile staining. Dry biomass, phosphate, and protein content of cultured B. braunii were measured at 3 days of intervals for 24 days. Biomass yield, hydrocarbon, carotenoid, and chlorophyll content were determined at the pH range of 6, 6.5, 7, 7.5, and 8 and various CO2 concentrations. The result showed that B. braunii collected from freshwater in Tenggarong can produce lipid globules. The highest growth of B. braunii was reached at day 15, while the optimal phosphate content was on the 12th day, and the protein was relatively stable during culture. The optimal weight of B. braunii biomass was reached at pH 7 and 4% CO2 and the highest hydrocarbon content was obtained at pH 8 and 4% CO2. The highest chlorophyll and carotenoid contents were obtained 4% CO2. In conclusion, B. braunii collected from Tenggarong was successfully cultured and able to produce lipid globules. The optimal conditions for its growth and production of hydrocarbon, phosphate, protein, chlorophyll, and carotenoid were at pH of 7-8 and 4% CO2.

Carbonized Rice Husk and Cocopeat as Alternative Media Bed for Aquaponic System

The study evaluates the suitability of carbonized rice husk and cocopeat substrates as alternative media bed in aquaponics unit for cultivation of red Nile tilapia and Gynura procumbens. Area occupied by the aquaponics unit is about 4.5 m2 and it was operated under equatorial climate conditions. Various substrates namely lightweight expanded clay aggregate (LECA), cocopeat, carbonized rice husk and a mixture of cocopeat-rice husk at ratio 1:1 were prepared using polybags for growing of the longevity spinach. The resultant effects from fish cultivation and plants growth on the water qualities and nitrification efficiency of the aquaponics unit were reported. The aquaponics unit were operated for twelve weeks and the values of pH, temperature, and dissolved oxygen level were measured to be within the range of 6.4-6.9, 27.7-29oC, and 5.5-7 mg·L-1, respectively. Survival rate for fish was 98% with specific growth rate (SGR) and food conversion ratio (FCR) of 6.9% per day and 1.13, respectively. Nutrient deficiency was not evident and plants showed healthy growth with harvest yield ranging between 3.6 and 3.9 kg·m-2. Results attained signified the suitability of utilizing carbonized rice husk and cocopeat as alternatives media bed compared to commercial media bed such as LECA.

Larva of greater wax moth Galleria mellonella is a suitable alternative host for the fish pathogen Francisella noatunensis subsp. orientalis

BackgroundFrancisella noatunensis subsp. orientalis (Fno) is the etiological agent of francisellosis in cultured warm water fish, such as tilapia. Antibiotics are administered to treat the disease but a better understanding of Fno infection biology will inform improved treatment and prevention measures. However, studies with native hosts are costly and considerable benefits would derive from access to a practical alternative host. Here, larvae of Galleria mellonella were assessed for suitability to study Fno virulence.ResultsLarvae were killed by Fno in a dose-dependent manner but the insects could be rescued from lethal doses of bacteria by antibiotic therapy. Infection progression was assessed by histopathology (haematoxylin and eosin staining, Gram Twort and immunohistochemistry) and enumeration of bacteria recovered from the larval haemolymph on selective agar. Fno was phagocytosed and could survive intracellularly, which is consistent with observations in fish. Virulence of five Fno isolates showed strong agreement between G. mellonella and red Nile tilapia hosts.ConclusionsThis study shows that an alternative host, G. mellonella, can be applied to understand Fno infections, which will assist efforts to identify solutions to piscine francisellosis thus securing the livelihoods of tilapia farmers worldwide and ensuring the production of this important food source.

Whole cell inactivated autogenous vaccine effectively protects red Nile tilapia (Oreochromis niloticus) against francisellosis via intraperitoneal injection.

Francisella noatunensis subsp. orientalis is a pathogen of tilapia and other warm-water fish for which no vaccines are commercially available. In this study, a whole cell formalin-inactivated vaccine was developedfor the first time using the highly virulent isolate STIR-GUS-F2f7 and the oil-based adjuvant Montanide™ ISA 763A VG. The efficacy of the vaccine was assessed in red Nile tilapia via intraperitoneal (i.p.) injection using homologous experimental infection and correlates of protection such as seral antibody production and bacterial loads in the spleen. For immunization, fish were i.p. injected with 0.1ml of the vaccine, the adjuvant alone or PBS. At 840 degree days post-vaccination, all fish were i.p. injected with 4.0×103 CFU/fish of pathogenic bacteria. The RPS at the end of the trial was 100% in the vaccinated group with significantly higher survival than in the adjuvant and control groups. The RPS in the adjuvant group was 42%, and no significant difference was seen in survival between this and the PBS group. Moreover, significantly higher antibody titres in the serum and significantly lower bacterial loads in the spleen were detected in the vaccinated fish by ELISA and qPCR, respectively. These findings highlight the potential of autogenous vaccines for controlling francisellosis in tilapia.

Bioprospecting of polyhydroxyalkanoates-producing bacteria from Indonesian marine environment

Abstract. Tan WA, Wijaya I, Purwadaria T. 2019. Bioprospecting of polyhydroxyalkanoates-producing bacteria from Indonesian marine environment. Biodiversitas 20: 1309-1315. Polyhydroxyalkanoates (PHA) are potential alternates to conventional synthetic plastics. PHA production in bacteria involves PHA synthase gene encoded by phaC. In this study, we isolated PHA-producing bacteria from the coastline and 1 mile from the coastline of three beaches in Indonesia. Further phaC detection and characterization of PHA production were conducted. The isolates were subjected to phylogenetic analysis based on 16S rDNA. Red Nile staining on minimal agar revealed that twenty-three isolates showed orange fluorescent, which indicated that they accumulated PHA in their cells. PCR detection showed the presence of PHA synthase class I-encoding gene phaC in twelve isolates. One representative amplicon was sequenced to verify its identity, in which it shared 86% similarity with the PHA synthase class I-encoding gene from an uncultured bacterium. Interestingly, the production of PHA in isolate ST.PA.75, which was closely related to Vibrio sp., was 2.1-fold higher than that in the Ralstonia eutropha JMP134 control. Three isolates showed similarity with bacterial genera and/or species for which PHA producing phenotypes had never been described before TP.SWC.20, which was closely related to Microbacterium arborescens, as well as TP.SWC.33 and TP.SWC.85, which were similar to Psychrobacter spp. Phylogenetic analysis showed that the PHA producing isolates were clustered into three phyla: γ-Proteobacteria, Actinomycetes, and Bacilli. A majority of the isolates (75%) were related to γ-Proteobacteria. In this study, we uncovered diverse novel promising strains for use in the production of PHA as a more environmentally-friendly alternative to hydrocarbon-based plastics.

Preferences of Giant Gouramy (Osphronemus gouramy, Lac, 1801.), Walking Catfish (Clarias sp.) and Red Nile (Oreochromis sp.) on Natural Feed in Fish Culture

The aim of this study was to determine the preference for plankton as natural feed by giant gourami, walking catfish, and red nile on intensive aquaculture system. The study was designed using Completely Randomized Design (RAL), with two replications. Each fish was kept in six concrete tanks with dimension 2x2x1 m³ and 60 cm water level. Water source were from wells. Commercial pellet feed was given in three times daily ad libitum. Water samples were filtered and two individual fish were collected for plankton samples from pond water and alimentary canal, respectively, every two week, simultaneously with water quality measurements. Plankton samples were preserved using 5% formaldehyde and was observed under a compound light microscope with 100x magnification. The amount of plankton in the alimentary canal was converted to volume. Data were analyzed descriptively. The result showed that the volume contents proportion of plankton in the alimentary canal was less than 1%. The volume of plankton proportion in the alimentary canal of red nile were found the most than other fish. Each fish had the same preference of plankton of Lepocinclis and Scenedesmus, but different from other species of plankton. The plankton that utilized by giant gouramy were Crucigenia, Diadesmis and Navicula, whereas walking catfish was Pediastrum, and red nile was Microcystis. The plankton that preferred by giant gouramy were Crucigenia, Oscillatoria, Splirullina, and Synedra, walking catfish was Navicula, while red nile were Chrysamoeba and Tintinnidium.

Performance of Water Treatment Techniques on Cocopeat Media Filled Grow Bed Aquaponics System

Aquaponics system is an innovative idea which combined both aquaculture and hydroponics systems. In this study performance of four different types of water treatment technique was investigated in cocopeat media filled grow bed aquaponics system. The techniques that had been investigated were mechanical filter, biological filter, combination of both mechanical and biological filters and grow media (cocopeat) itself as filtration media. The effectiveness these techniques were assessed through (i) water quality and nutrients level of circulated water and (ii) growth rates of plant (Gynura procumbens) and Red Nile Tilapia fish (Oreochromis niloticus) The (i) water quality (pH, temperature, total suspended solid and dissolved oxygen) (ii) nutrient level (ammonia, nitrite, nitrate) and (iii) grow rates of plant and fish were weekly measured for this study. The results revealed that cocopeat media filled grow bed only was insufficient to act as water treatment unit in the aquaponics system studied. The aquaponics system required at least a biological or mechanical filter to produce acceptable yields of fish and plant. For the long term, the combination of axial flow and biofilter with superlative ratio was suggested in order to produce the best performance of parameters studied. This integrated technique was able to maintain the water quality within the tolerance limit of fish besides supplying enough amount nutrients (especially nitrate) for the plant growth and easier maintenance work in terms of cleaning and disposal of sludge.

Comparison of lipid extraction methods for the microalgae Acutodesmus obliquus

Microalgae are widely used in the pharmaceutical and energy industries, therefore the conditions for their cultivation and extraction methods play an important role in the profiling and acquisition of lipids. The efficiency of lipid extraction from microalgae has attracted great interest from industry because of the wide variety of lipids and amounts that can be obtained. Acutodesmus obliquus (Scenedesmus obliquus UTEX 393) was used in this study. It was cultivated in Bold 3N medium modified with 75% nitrogen at 25°C, pH 6.8, 125 r/min and a photoperiod of 18/6 h and illuminated with white light provided by a Light-Emitting Diode Surface Mount Device extensions (LED SMD) with an intensity of 1200 µE/(m2•s). The cells were stained with the Red Nile (RN) technique to indicate lipid production. Four extraction methods were compared, classical, microwave (MW), Soxhlet, and ultrasound (US), using the same solvent proportions (hexane: chloroform: methanol=1:2:3). All samples were analyzed with Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography coupled to Mass Spectrometry (GC-MS). The results showed: 1) lipid production detected by RN was consistent with microalgal growth; 2) the MW technique was the best extraction method, according to the statistical analysis through Randomized Complete Block (RCB) design and performance of 4.6%; and 3) the presence of saturated and unsaturated acids was indicated by FTIR spectra. GC-MS was able to identify palmitic and linoleic acids as the likely major constituents of the sample. Keywords: Acutodesmus obliquus, lipid extraction, trans-esterification, Red Nile (RN) DOI: 10.25165/j.ijabe.20181105.3748 Citation: Hurtado D X, Garzon-Castro C L, Cortes-Romero J, Tello E. Comparison of lipid extraction methods for the microalgae Acutodesmus obliquus. Int J Agric & Biol Eng, 2018; 11(5): 211–217.