ISU for Sustainability

Embracing SDGs towards Quality Education and Academic Experience in the Countryside

Research | SDG 14 – Life Below Water

Technical Research Category

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Doname A. Reyes, Janet p. Cunanan, Dariane Jamaica V. Dacuro


The Rice eel (RE) Monopterus albus preservation has a significant impact on the quality of the final product. It is a highly perishable product and it is important to ensure the quality and safety that reaches the consumer This study aims to develop and evaluate the Quality Indices Method (QIM) scheme to measure the freshness of the raw fillet RE stored at refrigeration temperature (4○C) with different days of storage (DOS). Consumer survey test was also conducted to determine the marketability of RE.

The raw RE fillet was stored from 0 to 14 days at refrigeration with eight treatments with twenty-two (22) panelists in the QIM and thirty (30) respondents in the consumer survey test. The QI score and hedonic scale was used to determine the acceptable level.

There are differences between samples. The deterioration of the raw RE fillet occurred after 10DOS. Additionally, on zero (0) DOS was describing as “Like Very Much” LVM, while 2DOS to 10DOS as “Like moderately”, and 12DOS and 14DOS describe as “Like slightly” LS. The consumer survey shows that RE is not a major commodity in the Mallig region of Isabela.

This information may be used in the quality management of fresh RE fillets stored in the refrigerator to estimate the storage time and consumer survey test.

Floriebelle D. Querubin, Saul M. Rojas, James Kennard S. Jacob, Jose B. Abucay, Jr.


Marine ecosystems are known to hold diverse microorganisms including bacteria. However, the potential of bacteria from marine environments in the northern region of the Philippines, as a source of secondary metabolites with possible antibacterial properties, has not been widely studied. In this study, marine bacteria were isolated from water and sediment samples of Sta. Ana, Cagayan using standard enrichment procedures. The isolates were characterized based on their gram stain reaction and colony morphology and screened on their potential for antibacterial production employing agar plug method. The partial identity of the top-producing antibacterial isolates was determined based on 16S rRNA sequencing. A total of 16 isolates were obtained, 3 were Grampositive and 13 were Gram-negative. Colony characteristics of most isolates have round form, entire margin, convex elevation, and pale yellow to orange in color. Antibacterial screening revealed that 7 isolates have antimicrobial activity against the test organisms, namely Bacillus subtilis, Pseudomonas aeruginosa BIOTECH 1335, Escherichia coli BIOTECH 1634, and Salmonella enterica JCM 1651. Isolates SS3.5, NL1.5, NL4, and SSW1 have antagonistic activity B. subtilis while SS1, SS6, NL4 can inhibit the growth of P. aeruginosa BIOTECH 1335. Isolates SS6 and SS6.5 were active against the growth of E. coli BIOTECH 1634 and S. enterica JCM 1651, respectively. Sequence analysis of top-performing antibacterial isolates (NL1.5 and SSW1) revealed that NL1.5 fits in the same clade with Bacillus safensis with 69% bootstrap support while SSW1 was closely related to Bacillus filamentosus with 86% bootstrap support. Whole genome sequence of the best performing isolates and their bioactive crude extract will be subjected to high performance liquid chromatography in the future to determine their profile and active metabolite fraction. Overall, marine environment of Sta. Ana, Cagayan may have great potential as a source of marine bacteria producing secondary metabolites with antibacterial properties.

Narlyn C. Castillo, Noviel Delos Santos, James Kennard S. Jacob, Ron Patrick C. Campos, Jose Abucay, Jr.


Jagora asperata is an endemic freshwater snail species found in the Philippines. Currently, there is little research elaborating the secondary metabolites of the snail and few extensive studies to assess the bioactivity of this gastropod. The study was conducted to assess the bio-functionality and secondary metabolite constituents of Jagora asperata (locally called agurong). Results indicate the presence of saponins, tannins, cardiac glycosides, flavonoids, terpenoids and steroids in Jagora asperata ethanol extract. The extracts also showed promising antibacterial activities against Escherichia coli and Staphylococcus aureus, with mean zones of inhibition of 18.16 mm and 18.66 mm respectively. Cytotoxicity test also revealed low toxicity to brine shrimp. With these, Jagora asperata can be a candidate for exploitation and isolation of novel natural products with pharmacological importance.

Keywords: antibacterial, cytotoxicity, Jagora asperata, mollusc, secondary metabolites

Isagani P. Angeles, Jr., Levy D. Madrid, Laila M. Gallego, Raymond M. Pascua


This study evaluated dietary effects on growth performance, antioxidant capacity and metabolic response of Nile tilapia Oreochromis niloticus fed diet with raw azolla (RA) and fermented azolla (FA) following thermal stress. Fish were fed diet with different levels of RA [10% (10RA); 20% (20RA); 30% (30RA); 40% (40RA)], FA [10% (10FA); 20% (20FA); 30% (30FA); 40% (40FA)] and a control diet (C) without azolla for ten weeks. Growth and survival were monitored periodically. After rearing, fish were subjected to different temperature (low: 25°C, medium: 28°C and high: 33°C), and after a week, antioxidant capacity [superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR)] and metabolic response [glucose (Gluc), triglycerides (Trig) and lactate (Lac)] were analyzed. The growth performance of fish fed diet with 20RA, 20FD and 30FD were better as compared to C. In addition, fish fed with 10-40% FA had a better FCR as compared to C. Disregarding levels, fish fed with FA showed better %Survival after the feeding trial (74%). No significant difference was found on antioxidant capacity (SOD, GPx, GR) and metabolic response (Gluc, trig, Lac) of fish amon treatments. The activities of antioxidant capacity and metabolic response of Nile tilapia against thermal stress showed no interaction effect between levels and temperature. Overall, inclusion of 20RA and 20-30FD in the diet could be a potential feed ingredient in the diet of Nile tilapia

Laila M. Gallego, Isagani P. Angeles, Jr., Yew-Hu Chien


This study investigated the effects of light source [LED White (LW), fluorescent white (T5) and LED Blue (LB)] and photoperiod (12:12, 16:08, 24:00 light: dark) on growth of duckweed Landoltia punctata and the resulting effects on its water quality for 16 days. The average daily relative growth rate (RGR) reached about 0.519 g d-1. Both light source and photoperiod, had no significant difference on the mean RGR, however, their interaction had significant effects on duckweed’s growth (p≤0.05). Moreover, except T5 (24:00) > [T5 (12:12) ≥ T5 (16:08) ≥ LB (24:00)], LW (12:12) > [T5 (16:08) ≥ LB (24:00)], and LB (12:12) > LB (24:00), there were no differences in RGR in all pair-comparisons of treatment (p≤0.05). Nitrate (NO3-) influenced the most in weight increment (WI), 70 %. For light source and photoperiod effects on water quality, no total ammonia nitrogen (TAN) was detected in all treatments after 16 days while NO3- increased gradually. In addition, results show that most of the total nitrogen (TN) was contributed from NO3- (R2= 0.9999). Overall, our findings could contribute on producing duckweed in a controlled and programmed condition for maximum production and quality. Constructed models and practical application contribute in predicting nutrients sensitivity and proven useful in water management or water quality assessments.

Isagani P. Angeles, Jr., Evelyn C. Ame, Jonie C. yee, Levy D. Madrid, maricel M. Bagayan, Raymond M. Pascua


This study evaluated the dietary effect of Amaranthus spinosus Leaf Meal (ASLM) on growth performance, immune response and survival of Nile tilapia Oreochromis niloticus reared for 10 weeks following Aeromonas hydrophila infection. Fish were fed with a diet containing 25, 50, 75% of ASLM and 0% ASLM served as the Control-basal diet (C). Significant effects of treatments on growth, hematological profile, resistance to disease and survival were observed after 10 weeks of rearing and after infection. Wf, WG and SGR of fish fed with 50% ASLM were higher and FCR was lower than that of C. Wf, WG and SGR of ASLM50 were increased by 10%, 15% and 9% as compared to that of C, respectively. Moreover, FCR of ASLM50 was 10% lower than that of C. Hematological profile of Nile tilapia was comparable after 10 weeks of rearing. However, after challenge test, WBC and HGB of ASLM50 and ASLM75 were increased by 9% and 6% as compared to that of C, respectively while RBC, HGB and HCT of ASLM50 increased by 9%, 6% and 21% as compared to that of C, respectively. No significant difference was found on PLT among treatments after A. hydrophila infection. Fish fed with ASLM50 and ASLM75 had the highest percentage survival after challenge with A. hydrophila. Overall, these results indicated that ASLM enhances growth performance and improves resistance of Nile tilapia against A. hydrophila infection. ASLM could be therefore considered as potential alternative growth promoter and as natural immunostimulant for aquaculture.

Isagani P. Angeles, Jr., May-anne S. Canceran, Noel M. Patricio


The present study aims to evaluate the phytochemical constituents and proximate composition of Padina sp. The Padina sp. were collected by scuba diving and handpicking from the rocky substratum at depth of 1-3 m along the subtidal areas at Matara White Sand Beach and Coral Reefs, Gonzaga, Cagayan, Philippines. The phytochemical screening revealed the presence of flavonoids, alkaloids, saponins, glycosides and tannins. Whereas, Saponins and Glycosides were abundant in ethanol and n-hexane extraction. However, tannins were absent in both n-hexane and dichloromethane extraction. The presence of different secondary metabolites were important indicators of the anti-microbial properties of Padina sp. In dry weight basis of proximate analysis per 100 g of seaweeds showed high content of Moisture (8.99%), Crude Protein (4.28%), Ash (50.09%) and Total Carbohydrates (36.64%) but lowest in Crude Fat (<0.10%). The study reveals that Padina sp. contains essential nutrients that are potential for the growth, survival and as an immune booster for fish. This study concludes that Padina sp. are potential source of bioactive substance. It is a potential agent in developing an anti-pathogenic drugs and/or supplement for stimulating the immune system of fish and shrimps in the aquaculture industry. A further study should be conducted to test the actual performance of Padina sp. extracts in stimulating the immune system or treating diseased aquaculture fish or shrimp species.

Technological Research Category