Now showing items 1-15 of 15

    • Article

      Aflatoxin B1 contamination of shrimp feeds and its effect on growth and hepatopancreas of pre-adult Penaeus monodon 

      MN Bautista, CR Lavilla-Pitogo, PF Subosa & ET Begino - Journal of the Science of Food and Agriculture, 1994 - Society of Chemical Industry
      A survey of aflatoxin B1 (AFLB1) levels in commonly used commercial shrimp finisher feeds in the Philippines showed a various range of values from not detected to 120 μg kg−1 using high-performance thin-layer chromatography. Six experimental diets were prepared to contain various levels of AFLB1 based on survey results to determine the effects of such contamination in pre-adult shrimp Penaeus monodon (17.5 ± 0.6 g). Results showed that shrimps fed diets containing AFLB1 greater than or equal to 73.8 μg kg−1 gave comparatively poor growth rate and higher susceptibility to shell diseases. No AFLB1 residues were detected in sampled whole shrimp tissues after 62 days of exposure to AFLB1 containing diets indicating a low potential for transmission of the toxin from edible shrimp tissues to consumers. Histopathological alterations in the hepatopancreas of shrimp chronically exposed to AFLB, were observed in all samples. The degree of alterations correlated with the level of AFLB1. Based on growth performance, pre-adult shrimps can tolerate AFLB1 levels of up to 52.3 μg kg−1 in the feeds although histopathological changes were already evident in the tissues of shrimps given diets with 26.5 μg kg−1 AFLB1.
    • Article

      Analysis of nitrite in aqueous solutions containing concentrated matrix ions using an octadecyl-poly(vinyl alcohol) gel microbore column and an electrochemical detector 

      S Rokushika, K Kihara, FM Yamamoto & PF Subosa - Journal of High Resolution Chromatography, 1991 - Dr. Alfred Huethig Publishers
      The importance of the analysis of low level nitrite concentrations in aqueous samples is increasing in various fields such as environmental, food, and aquaculture chemistry. Recent progress in ion chromatography paved the way to the direct analysis of nitrite in water samples at ppm to sub ppb levels. However, analysis of low level nitrite in highly concentrated salt matrix still remains a difficult problem. The presence of a large amount of the matrix ion makes establishment of an ion exchange equilibrium very difficult in the column, often resulting in bad peak shapes [1].

      In previous papers, we reported the analysis of a nitrite and other anions in chloride matrix on a conventional low capacity anion-exchange column by means of a heart-cut and recycling method [1] and by using a potassium chloride eluent [2]. To monitor the nitrite peak, both a UV detector and a conductimetric detector has been used [3]. Several groups have demonstrated the potential of an electrochemical detector for a specific and sensitive detection of nitrate. [4-6].

      Poly(vinyl alcohol) (PVA) gel have been introduced recently as a chemically stable HPLC column packings [7-9]. It was found that when an acidic eluent was employed, a PVA gel and its acylated gel columns produced large capacity factors for nitrite [10].
    • Article

      Butylated hydroxytoluene: its effect on the quality of shrimp diet stored at various temperatures and on growth and survival of Penaeus monodon juveniles 

      MN Bautista-Teruel & PF Subosa - Aquaculture, 1999 - Elsevier
      Shrimp diets with and without the antioxidant, butylated hydroxytoluene (BHT) were stored at 10°, 20°, 28°–30°, and 40°C for 10 weeks. To monitor lipolysis and lipid oxidation, free fatty acid (FFA) content, peroxide values (PVs), and malonaldehyde (MAL) levels were measured from the extracted lipids of the stored diets. Fatty acid levels of the diets increased between the initial and final samplings and the increase was higher (8.4%) in diets without BHT stored at 40°C after 10 weeks. Peroxide values of the extracted lipids were low and fluctuated monthly between 2.2 and 7.4 mmol/kg fat. MAL levels increased in diets with and without BHT except those stored at 10°C for 4 weeks. Diets with BHT stored at 10°C had the lowest (8.7 mg MAL/kg fat) MAL levels and diets without BHT stored at 40°C for 10 weeks had the highest (16.9 mg MAL/kg fat). Shrimp fed diets with BHT gained 5.7–6.4× their initial weight after 10 weeks of rearing. Their growth was significantly better than those fed diets without BHT (4–6×) during the 60-day culture period. Survival was significantly higher in those fed diets with BHT (87–88%) than those without BHT (75–85%). No hepatopancreatic lesions were seen in shrimp samples fed diets with and without BHT and stored at various temperatures. The incorporation of BHT in shrimp feed is necessary if the feed is to be stored at 40°C for 10 weeks.
    • Article

      Changes in shrimp feed quality and effects on growth and survival of Penaeus monodon juveniles 

      MN Bautista & PF Subosa - Aquaculture, 1997 - Elsevier
      Five practical shrimp diets were formulated to contain 1, 10, 20, 50, and 100 g tetraethoxypropane (TEP) kg−1 diet. A diet with no added TEP served as the control. Diets were fed to Penaeus monodon (average weight 4.84 ± 0.11 g) juveniles to determine the level of fat oxidation tolerable to shrimp. Changes in shrimp feed quality were monitored by physical evaluation, thiobarbituric acid (TBA) values, fatty acid composition, and histological examination. Effects of feed quality on growth and survival of shrimp were evaluated. Results showed significant differences (P < 0.05) in TBA values among treatments. Animals fed on diet 6, which contained 100 g TEP kg−1 diet, showed signs of physical deterioration after 6–8 weeks. This diet had a significantly higher TBA value (1262 mg malonaldehyde kg−1 fat) than the other treatments. The unsaturated fatty acid content of the diet decreased as its TEP content increased. Weight gains of shrimp fed diet 5 (50 g TEP kg−1 diet) and diet 6 were significantly lower than those fed the other diets while survival was similar. Hepatopancreatic lesions were not evident in all samples. Fat oxidation levels expressed in terms of TBA values of up to 828 mg mal kg−1 fat can be tolerated by Penaeus monodon juveniles in terms of growth response.
    • Article

      Chicken manure, rice hulls, and sugar-mill wastes as potential organic fertilizers in shrimp (Penaeus monodon Fabricius) ponds 

      PF Subosa - Aquaculture, 1992 - Elsevier
      Shrimp (Penaeus monodon Fabricius) were cultured (3000 juveniles/ha) in 50-m2 earthen ponds fertilized with composted agricultural and industrial wastes at a basal application rate of 2 ton/ha. The following materials were tested: chicken manure, rice hulls, and three types of sugar-mill wastes: mudpress, boiler ash, and bagasse.

      After 66 days significant differences existed among treatments (P < 0.05) in mean body weight and gross production of shrimp. A significantly higher mean body weight (28.8 g) was obtained with boiler ash than with chicken manure (26.05 g) and these were followed by mudpress (25.8 g) and rice hulls (25.05 g) which were not significantly different from each other. The mean body weight using bagasse (22.0 g) was significantly lower than in the other treatments followed by the control (no fertilizer, 19.6 g). High survival rates were obtained in all treatments. The pond yields ranged from 53.7 to 86.4 kg/ha after 66 days with daily weight increments of the shrimp ranging from 0.18 to 0.41 g.
    • Article

      Effects of antioxidants on feed quality and growth of Penaeus monodon juveniles 

      MN Bautista, PF Subosa & CR Lavilla-Pitogo - Journal of the Science of Food and Agriculture, 1992 - Wiley-Blackwell
      Four practical diets were formulated to contain 0.05%, of the following antioxidants: butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA), propyl gallate (PG) or ethoxyquin (ETHQ). A fifth diet, with no added antioxidant, served as a control. The diets were fed to Penaeus monodon juveniles to determine the effects of antioxidants on feed quality and growth of the animals. The results showed no significant difference (P> 0.05) between the control and the feeds containing antioxidants in 2-thiobarbituric acid values after 0, 30, 60, and 90 days storage, respectively. There was a significant difference by the 120th day of storage, but no signs of physical deterioration were observed in any of the diets. The highest weight gains (704% and 742%) were obtained with shrimps fed diets with BHT and BHA, respectively, as antioxidants. Hepatopancreatic lesion formation was evident with shrimps fed diets containing antioxidants but not with shrimps fed a diet without antioxidant. Shrimps fed with BHT-added feed showed fewest lesions in the hepatopancreas. Although all shrimp samples given feed containing PG and ETHQ showed lesions, these were patchy in nature and did not affect the growth rates of the animals.
    • Article

      Evaluation of organic and inorganic fertilizers in brackishwater milkfish ponds 

      I Bombeo-Tuburan, RF Agbayani & PF Subosa - Aquaculture, 1989 - Elsevier
      The study was conducted in twelve 144-m2 ponds to evaluate the effect of different organic and inorganic fertilizers on the growth, survival, gross production, and profitability of marketable milkfish. The following treatments were used: Treatment I, SEAFDEC traditional fertilization practice (16-20-0 at 50 kg/ha and 45-0-0 at 15 kg/ha); Treatment II, half-dosage of Treatment I; Treatment III, chicken manure at 0.5 ton/ha; and Treatment IV, MASA (processed from agricultural and industrial wastes) fertilizer at 0.5 ton/ha. All treatments were applied once in every 2 weeks.

      No significant difference (P > 0.05) existed in the harvest and production of milkfish among the treatments. However, economic indicators such as return-on-investment (ROI), payback period, and marginal analysis ranked the performance of the fertilizer treatments in the order of I, II, III and IV.

      Fish kills occurred in three ponds applied with chicken manure and MASA fertilizer. This could have been due to a heavy build-up of organic matter in the pond bottom which led to the collapse of the benthic algal community, depletion of dissolved oxygen and the presence of hydrogen sulfide. It is therefore suggested that a lower dosage of organic fertilizer should be applied in ponds especially during the rainy season.
    • Article

      Influence of stocking density and fertilization regime on growth, survival and gross production of Penaeus monodon Fabricius in brackishwater ponds 

      PF Subosa & MN Bautista - The Israeli Journal of Aquaculture-Bamidgeh, 1991 - Society of Israeli Aquaculture and Marine Biotechnology
      Twelve 0.1 ha earthen ponds were stocked at 3,500 or 7,000/ha with 1-month old nursery reared Penaeus monodon Fabricius (1.73 g). Fertilizer treatments were 125 kg chicken manure plus 4.1 kg diammonium phosphate (18-46-0) and 6.56 kg urea (45-0-0) per application for treatments U3500 and U7000 and 125 kg chicken manure plus 8.15 kg diammonium phosphate and 0.89 kg urea per application for treatments P3500 and P7000. Fertilizers were broadcast 10 days after pest eradication and every two weeks thereafter. Water was exchanged (20%) one day before fertilization throughout the 86-day culture period. Shrimp yields at harvest were: P7000, 193.6 kg/ha; P3500, 119.4 kg/ha; U3500, 97.5 kg/ha; and U7000, 82.4 kg/ha. Mean survival for each treatment was 96.2%, 97%, 89.3% and 75%, respectively. There were significant differences in shrimp yields at harvest among treatments (p < 0.05).
    • Article

      Ion chromatography of inorganic anions in brine samples 

      PF Subosa, K Kihara, S Rokushika, H Hatano, T Murayama, T Kubota & Y Hanaoka - Journal of Chromatographic Science, 1989 - Oxford University Press
      An ion chromatographic method for separating and detecting anions in brine samples is described. Nitrite, bromide, nitrate, and sulfate ions in brine samples are well separated when chloride ion concentration in the sample solution is below 2000 ppm. However, at higher chloride concentrations, nitrite and chloride peaks are not resolved. Low level nitrite ion in the brine sample is separated from a major chloride ion by a heart-cutting and recycling system. After elution, the unresolved portion, including the nitrite ion, is cut and trapped in a 10-mL sample collecting loop and reinjected on the column by using 6- and 4-port valve systems. The detection limit of nitrite spiked in the seawater samples is 0.5 ppm.
    • Article

      Ion chromatography of nitrite, bromide and nitrate ions in brine samples using a chloride-form anion-exchange resin column 

      S Rokushika, K Kihara, PF Subosa & WX Leng - Journal of Chromatography A, 1990 - Elsevier
      In aquaculture research, maintenance of water culture quality is of great importance. Recent improvement in fishpond management and fish culture systems, such as intensive feeding and fertilization, have created complex problems. Deterrioration of weter quality is primarily the resulting effect of these improvements. Foe example, high-protein feeds and nitrogen fertilizers applied in fishponds produce considerable amount of nitrate in the water. Moreover, their synergistic effects cannot be ignored. Hence the routine determination of nitrite in fishpond water is required.

      Since its introduction by Small et al., ion chromatography has been widely used for the determination of ions in water. However,the presence of very high concentrations of chloride is the main obstacles in the analysis of seawater samples, affecting the separation and detection not only of nitrite but also of other anions.

      Itoh and Shinbori applied ion chromatography to the analysis of seawater using a 125-cm long column and a conductimetric detector. This technique provided by a simple and sensitive analysial method for brine samples. However, nitrite could not be determined owing to the presence of a large chloride peak.

      Attempts to determine nitrite in seawater also led to innovations in the methodology. Lee and Field employeed a post-column cerium flourescence detection system to determine nitrite and nitrite in drinking water and seawater. The use of a pretreatment column in the silver form for removal of chloride has been reported.

      Various detectors have been applied in ion chromatography in addition to the conductimetric detector. The UV detector has been shown to be luseful detector for several kinds of inorganic anions. Selected detection of specified inorganic ions can be achieved by tuning the wavelength of the UV detector in ion chromatography and also in ion-exclusion chromatography. The elemination of the chloride matrix interference in the sub-ppm determination of nitrite in seawater was achieved by a heart-cutting and recycling method using a dual detection system consisting of conductimetric and UV detectors. This method, however, requires valve switching during analysis and needs a long analysis time.

      This paper describes a simple and rapid method of UV-absorbing anions, such as nitrite, nitrite and bromide, in brine samples using a chloride-form anion-exchange resin column combined with a UV detector.
    • Article

      The macronutrient composition of natural food organisms mass cultured as larval feed for fish and prawns 

      OM Millamena, VD Peñaflorida & PF Subosa - The Israeli Journal of Aquaculture-Bamidgeh, 1990 - Society of Israeli Aquaculture and Marine Biotechnology
      The macronutrient composition of natural food organisms that are mass cultured as feed for the larval stages of fish and prawns in the SEAFDEC Aquaculture Department was determined by chemical analysis. The food organisms included five species of marine phytoplanktons (algae): Chaetoceros calcitrans, Skeletonema costatum, Tetraselmis chui, Chlorella vulgaris and Isochrysis galbana, and two zooplanktons: Artemia sp. nauplii (San Francisco Bay strain) and Brachionus plicatilis. The algal species were grown in batches on Guillard and Ryther media and harvested during the exponential phase of growth using a procedure which preserved cellular integrity and prevented cell lysis. The zooplankton were cultured using standard techniques adopted at the SEAFDEC Larval Food Laboratory. Each species was analyzed for proximate composition (protein, fat, fiber and ash) and for mineral content (calcium and phosphorous). Nitrogen-free extract (NFE) was determined by difference. For the five algal species, the protein, fat and NFE contents varied from 22% to 48%, 2% to 16% and 14% to 24%, respectively. The zooplanktons had higher protein and fat contents than any of the phytoplankton species except I. galbana which had the highest fat content. On the other hand, the phytoplanktons, particularly the diatoms which have a siliceous cell wall, contained significantly higher quantities of inorganic matter (ash). C. vulgaris had the highest fiber content which may be attributed to its cellulosic cell wall.
    • Article

      Performance of recirculating systems for prawn hatchery and broodstock maturation tanks 

      OM Millamena, CM Casalmir & PF Subosa - Aquacultural Engineering, 1991 - Elsevier
      The potential use of recirculating systems with facilities for waste removal for prawn (Penaeus monodon) hatchery and broodstock maturation tanks was investigated. Recirculating systems evaluated for larval culture tanks were biological filtration and zigzag stream sedimentation. Systems using airlift and airstones as aeration devices with partial water change but with no provision for recirculation served as control. Results showed successful rearing of Penaeus monodon (nauplii-postlarvae) in systems with facilities for wastewater recirculation. Aeration systems became ineffective in maintaining acceptable water quality as shown by increases in 5-day biochemical oxygen demand (BOD5), ammonia (NH4-N) and nitrite (NO2-N) nitrogen, and decreases in dissolved oxygen (DO).

      For broodstock maturation, a recirculating system with a preconditioned biological filter was compared with a flow-through system. Biological filtration proved to be useful in meeting water quality requirements. Nitrification was satisfactory with ammonia levels lower than 1·0 mg liter−1. The pH values in the biofilter effluent were maintained at 7·8–8·3. BOD5 levels were below 10 mg liter−1 while DO tended to drop due to the nitrifying activity of the filter. Better reproductive performance of Penaeus monodon broodstock was obtained in the recirculating system than in the flow-through system.
    • magazineArticle

      Shrimp (Penaeus monodon Fabricius) production in brackishwater ponds applied varying fertilizer combinations 

      PF Subosa & MN Bautista - SEAFDEC Asian Aquaculture, 1992 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Details are given of the production of Penaeus monodon in the Philippines reared in brackishwater earthen ponds applied with different fertilizer combinations, namely diammonium phosphate, urea and chicken manure. Results show that the shrimp showed higher yields in fertilized ponds, but increasing the concentration of fertilizers did not give a marked increase in yield - the excess fertilizer was wasted.
    • Conference paper

      Trace analysis of nitrite ion in seawater using ion chromatography. 

      PF Subosa, S Rokushika, H Hatano, T Murayama, T Kubota & Y Hanaoka - In Proceedings of the Symposium in Liquid Chromatography, 26-27 August 1988, Kyoto, Japan, 1988 - Kyoto University
      An ion chromatographic method of separating and detecting nitrite in sea water is described. The system includes precolumn, new hydrophilic separation column, suppressor and two-valve system. Nitrite was diverted, trapped and separeted in a 2.6-ml sample loop using 6- and 4-port valves. The eluent used was 14.4 mM sodium hydrogen carbonate at flow-rate oflml/min while the scanvenger was 14 mM sulfuric acid. Nitrite recovery achieved was 100±2%. The minimum detection limit was 0.15 ppm with the signal-to-noise set 2.5 Nitrite recovery obtained using different mixing ratios of sodium hydrogen carbonate and sodium carbonate were lower. Eluent ph and compoosition affected both peak heights and retention timed of nitrite and other anions.
    • Article

      Yield of Penaeus monodon Fabricius in brackishwater ponds given different fertilizer combinations 

      PF Subosa & MN Bautista - Aquaculture, 1991 - Elsevier
      Yields of Penaeus monodon Fabricius in brackishwater earthen ponds were determined using different fertilizer combinations in two sets of experiments. Results indicated that the use of fertilizers was vitally needed to sustain growth of shrimps at a stocking density of 5000 individuals/ha. Application of urea (45-0-0) and diammonium phosphate (18-46-0) fertilizers at nitrogen to phosphorus fertilizer rates (N:P2O5) of 15:15 and 30:15 kg/ha, together with 1 t/ha of chicken manure, was inexpensive and resulted in better yields. In another experiment, increase in the amount of nitrogen and phosphorus fertilizers did not significantly improve prawn yields, but did increase the cost of production. Different salinity levels affected survival in both experiments.