Now showing items 985-1004 of 1074

    • Article

      Tank culture of Gracilaria heteroclada (Zhang et Xia) 

      MRJ Luhan, J Tanaka & Y Aruga - Philippine Agricultural Scientist, 2003 - College of Agriculture and Central Experiment Station, University of the Philippines Los Baños
      Culture conditions in tanks were manipulated to improve the growth and agar quality of Gracilaria heteroclada Zhang et Xia. Specific growth rates during culture ranged from -0.51% to 1.40% and gel strength of agar from 439 to 2155 g cm-2. G. heteroclada at a stocking density of 2kg ton-1 and fertilized with ammonium chloride at 40 mg L-1 grew best when water was changed once a month and ammonium chloride was replenished at 20 mg L-1 after water change. When water was not changed, good growth was observed in plants supplied with 1 mg L-1 diammonium phosphate on the 3rd wk of culture.
    • Article

      Taxonomy and phylogeny of Nephroselmis clavistella sp. nov. (Nephroselmidophyceae, Chlorophyta) 

      DG Faria, A Kato, MR de la Peña & S Suda - Journal of Phycology, 2011 - Wiley-Blackwell
      Nephroselmis clavistella D. G. Faria et S. Suda sp. nov. is collected from coastal sand samples from the eastern and western coasts of Okinawa-jima Island, Japan. The description of the cultured strains is based on light and electron microscopic observations. The cultured strains are phylogenetically analyzed based on 18S rDNA sequences. The cells are remarkably right–left flattened and appear round or ellipse when viewed from their right or left side, and are ∼5.0 μm in diameter. The posterior flagellum curved around the cell body at rest. A single, parietal, crescent chloroplast is yellowish green and contains one conspicuous eyespot in its anterior-ventral edge near the short flagellum base. A pyrenoid with one starch sheath is located dorsal of the chloroplast. The cells are divided by transverse binary cell division, as is common in other species of this genus. The cell body is covered with five types of scales, and among them four scale types are similar to Nephroselmis rotunda. The fifth scale type is a distinctive spiny and club-shaped stellate scale with 10 spines, four of the 10 spines extended ∼150 nm and each are slightly curved with a hook at the end, whereas six spines are club-shaped blunt ended. This scale morphology, an important taxonomic characteristic, has never been described before for the genus Nephroselmis. The cell’s morphology is distinctive from previously described Nephroselmis species, and its unique scale characteristics led us to name this newly proposed species “clavistella,” meaning club star.
    • Article

      Techniques on algae harvesting and preservation for use in culture and as larval food 

      OM Millamena, EJ Aujero & IG Borlongan - Aquacultural Engineering, 1990 - Elsevier
      A method of algae harvesting and preservation was developed. Test algal species consisted of two diatoms: Chaetoceros calcitrans and Skeletonema costatum, and two flagellates: Tetraselmis chui and Isochrysis galbana. Chemical flocculation using alum and lime were evaluated as methods of harvesting algae. Freezing and sun-drying were used as methods of preservation with viability tests done on frozen samples. The usefulness of sun-dried algae was evaluated through its ability to support survival of Penaeus menodon larvae. Results showed that alum and lime flocculation were effective for Chaetoceros, Tetraselmis and Skeletonema but ineffective for Isochrysis. Optimum pH for algae removal with alum was found to be 6.5. With lime, algae removals increased with pH and was optimum at pH 9.5. A simple freezing technique preserves the viability of algal concentrates for culture purposes. Good performance of sun-dried Chaetoceros and Tetraselnlis suggests that these algae may be used as larval feed for Penaens monodon alone or supplementarily to eliminate complete dependence on carefully-timed live algal production.
    • Article

      Temperature and size range for the transport of juvenile donkey's ear abalone Haliotis asinina Linne 

      SMA Buen-Ursua & G Ludevese - Aquaculture Research, 2011 - Blackwell Publishing
      Live transport of hatchery-produced juvenile donkey's ear abalone Haliotis asinina Linne was examined to evaluate the effect of transportation on the survival of juvenile abalone. Simulated transport experiments were conducted to determine the appropriate temperature using 5, 10 and 20 g L−1 of ice to air volume for 8 h and the appropriate size using two size groups (Size A, 15–20 mm, 0.5–1.3 g, and Size B, 30–35 mm, 5.3–8.5 g) up to 24-h out-of-water live transport. Survival was significantly higher (P<0.001) when 10 g L−1 of ice was used to decrease the temperature to the range of 17–23 °C. At this temperature, both size groups subjected to simulated transport for 8 and 10 h had 100% survival after 48 h, while mortality occurred in abalones subjected to 16 and 24 h of simulated transport. The Size B abalone subjected to 24 h of transport had significantly higher survival (64.4 ± 2.9%) (P<0.001) than the Size A abalone (5.5 ± 1.6%) after 48 h. Live juvenile abalone were successfully transported to the field applying the protocols developed in the lab experiment. This study serves as a guide for handling and shipping live juvenile abalone.
    • Article

      Temperature fluctuation, low salinity, water microflora: Risk factors for WSSV outbreaks in Penaeus monodon. 

      EA Tendencia & JAJ Verreth - The Israeli Journal of Aquaculture-Bamidgeh, 2011 - Society of Israeli Aquaculture and Marine Biotechnology
      White spot syndrome virus (WSSV) has been devastating the shrimp industry for almost a decade. This study compares water parameters, alkalinity, and microflora in three ponds on a farm on Negros Island (Philippines) during two production cycles where WSSV infection resulted in an outbreak in 2006 but not in 2005. The total bacterial count of the pond water in 2005 was about twice as high as in 2006. However, luminous bacterial counts were twice as high in 2006 than in 2005 and total presumptive Vibrio, as counted on Vibrio selective thiosulfate citrate bilesalt sucrose (TCBS) agar, was over ten times higher, with a greater percentage of green colonies. More green colonies might indicate a higher concentration of harmful Vibrio bacteria. Total alkalinity for both production cycles was within the normal range while temperature, salinity, pH, and dissolved oxygen varied and sometimes fell below or exceeded the acceptable range. In 2006, there were more instances during which the temperature fluctuated 3-4°C within the period of 07:00-17:00, and salinity more often dropped below 15 ppt. Our survey suggests that WSSV outbreak are triggered by water temperature fluctuations of 3-4°C, coupled with low salinity and a high presumptive Vibrio count
    • Article

      Temporal changes in innate immunity parameters, epinecidin gene expression, and mortality in orange-spotted grouper, Epinephelus coioides experimentally infected with a fish pathogen, Vibrio harveyi JML1 

      EC Amar, JP Faisan Jr., MJS Apines-Amar & RV Pakingking Jr. - Fish and Shellfish Immunology, 2017 - Elsevier
      Changes in innate immunity parameters and epinecidin mRNA transcript levels were examined to characterize the non-specific immune response of E. coioides to pathogenic V. harveyi JML1 isolated from affected cage-cultured fish. After fish had been injected with bacteria at a dose causing 30% mortality, blood and tissue samples were collected at 0, 6, 12, 24, 48, 72, 96, 120, and 240 h post-infection (hpi) for assessment of indices such as the oxidative burst (OB) and phagocytic index (PI) of head kidney cells, and lysozyme activity (LYS) and total immunoglobulin (Total Ig) levels of the plasma. The epinecidin mRNA transcript levels (EGE) from skin, gills, liver, kidney, and spleen tissues were also determined by gelbased RT-PCR. Lastly, daily mortality (DM), liver total bacterial load (TBC), and presumptive Vibrio count (TVC) were monitored up to 240 hpi. The results revealed that bacteria proliferated rapidly in fish tissue, reaching peak densities at 24 hpi for both TBC and TVC but was on a downward trend thereafter. The pattern in fish mortality closely correlated with TBC and TVC. Total Ig, OB, and PI in E. coioides were suppressed in the early part of infection when V. harveyi load was high but recovered and later increased as bacterial density declined. LYS and EGE were consistently high and their activities were not hampered by bacterial infection. The study demonstrated that V. harveyi JML1 interacts with E. coioides by transiently inhibiting some immune parameters resulting in mortalities. However, consistently high LYS, upregulated EGE, and resurgent PI, OB and Total Ig conferred resistance and subsequent recovery in the fish. The study provides new insights on the interaction between E. coioides and V. harveyi JML1 that can aid in formulating health management strategies for groupers. Further studies on prophylactic interventions to enhance the innate immune response in grouper during infection with V. harveyi JML1 are suggested.
    • Article

      Terrestrial leaf meals or freshwater aquatic fern as potential feed ingredients for farmed abalone Haliotis asinina (Linnaeus 1758) 

      OS Reyes & AC Fermin - Aquaculture Research, 2003 - Blackwell Publishing
      Three terrestrial leaf meals, Carica papaya, Leucaena leucocephala, Moringa oliefera and a freshwater aquatic fern, Azolla pinnata were evaluated as potential ingredients for farmed abalone diet. All diets were formulated to contain 27% crude protein, 13% of which was contributed by the various leaf meals. Fresh seaweed Gracilariopsis bailinae served as the control feed. Juvenile Haliotis asinina (mean body weight=13.4±1.6 g, mean shell length= 38.8±1.4 mm) were fed the diets at 2–3% of the body weight day–1. Seaweed was given at 30% of body weight day–1. After 120 days of feeding, abalone fed M. oliefera, A. pinnata-based diets, and fresh G. bailinae had significantly higher (P<0.01) specific growth rates (SGR%) than abalone fed the L. leucocephala-based diet. Abalone fed the M. oliefera-based diet had a better growth rate in terms of shell length (P<0.05) compared with those fed the L. leucocephala-based diet but not with those in other treatments. Furthermore, protein productive value (PPV) of H. asinina was significantly higher when fed the M. oliefera-based diet compared with all other treatments (P<0.002). Survival was generally high (80–100%) with no significant differences among treatments. Abalone fed the M. oliefera-based diet showed significantly higher carcass protein (70% dry weight) and lipid (5%) than the other treatments. Moringa oliefera leaf meal and freshwater aquatic fern (A. pinnata) are promising alternative feed ingredients for practical diet for farmed abalone as these are locally available year-round in the Philippines.
    • Article

      Test of refined formulated feed for the grow-out culture of tropical abalone Haliotis asinina (Linnaeus 1758) in concrete land-based tanks 

      MN Bautista-Teruel, JRH Maquirang, MR de la Peña & VT Balinas - Journal of Shellfish Research, 2016 - National Shellfisheries Association
      A refined formulated feed for the grow-out culture of tropical abalone Haliotis asinina was evaluated to assess its suitability for a shorter culture period (<8 mo). Refinement procedures focused on the application of additional binder (sodium alginate), use of different feed forms (molo and noodle forms), and incorporation of Spirulina spp. as alternate protein source in partial replacement of other protein sources. Groups of 22 postlarval abalone with mean initial shell length (SL, 29 ± 0.01 mm) and weight (5.67 ± 0.06 g), harvested from the mollusc nursery of Southeast Asian Fisheries Development Center, Aquaculture Department in Tigbauan, Iloilo, were stocked each as replicate in five plastic trays measuring 31.7×43.5×9.0 cm. The trays were suspended in five 1×2×1-m concrete land-based tanks representing the five dietary treatments. Abalone were fed either the refined formulated diet,molo form(RF-M), refined formulated diet, noodle form(RF-N), unrefined formulated diet, noodle form(UF-N), unrefined formulated diet, molo form (UF-M), and seaweed (NF), as the reference diet. Formulated diets and natural food were given at 2%-3% and 10%-15% (wet weight) of the body weight, respectively, once daily at 1600 h for 180 days. Water quality measurements were maintained at desired levels. A flow-through filtered seawater systemwith continuous aeration was provided in each tank. A parametric one-way analysis of variance (ANOVA) and Tukey's post hoc test were used to test the differences in abalone SL, weight gain (WG), and specific growth rate (SGR) while nonparametric Kruskal-Wallis test was used for daily growth increase in SL (DGSL) and feed conversion ratio (FCR) among the various dietary treatments. Percent diet water stability and apparent digestibility coefficient for dry matter (ADMD) and apparent digestibility of seaweed as ingredient were, likewise assessed. A Hedonic scale taste test analysis was done to assess differences in abalone meat quality. Highest mean WG (239.17% ± 26.05%), mean SL increase (91.51% ± 3.28%), DGSL (2,296.67 µm/day), SGR (4.04 ± 0.27) were attained with abalone fed RF-N. Values, however, were not significantly different (P > 0.05) for all growth parameters in RF-M except for percent increase in SL at 74.25 ± 3.11. Abalone given UF-N and UF-M showed significantly lower mean WG and SL. Survival was high and was significantly different (P < 0.05) between treatments. The highest FCR was obtained with abalone fed seaweeds. Apparent digestibility for dry matter of both the RF and UF were high at 95.67% ± 1.17% and 95.95% ± 0.45%, respectively. Apparent digestibility of ingredient seaweed was 99.4% ± 1.38%. Regression analysis of data showed better percent water stability for RF (57%; R2 = 0.954) compared with UF (38%; R2 = 0.790) after 24 h. Meat quality of the final product assessed through Hedonic scale taste testing and one-way ANOVA did not show any significant variations in taste, texture, color, odor, and general acceptability. Results have demonstrated that the refinement done on the formulated feed may enable the abalone to grow to its marketable size of about 5-6 cm in a shorter culture period (180 days) in concrete land-based tanks.
    • Article

      Test of size-specific mass selection for Nile tilapia, Oreochromis niloticus L., cage farming in the Philippines 

      ZU Basiao & RW Doyle - Aquaculture Research, 1999 - John Wiley and Sons
      One generation of mass selection based on the collimation procedure (early culling of large fry) was applied on Nile tilapia, Oreochromis niloticus L., in net cages set in Laguna de Bay, Philippines. The objective was to test the effectiveness of a low-cost, small-scale broodstock improvement procedure in this culture environment. Directional selection was performed in two steps after initial removal of large fry at 21 days. Selection of parents and testing of the offspring were also conducted in hapa net cages set up in Laguna de Bay. The selection resulted in a significant positive response of 3% relative to the control, which represents a projected 34% gain over 5 years in Laguna cage culture. The realized heritability is approximately 16%.
    • Article

      Testicular histology and serum steroid hormone profiles in hatchery-bred catfish Clarias macrocephalus (Gunther) during an annual reproductive cycle 

      JD Tan-Fermin, T Miura, H Ueda, S Adachi & K Yamauchi - Fisheries Science, 1997 - Japanese Society of Fisheries Science
      Testicular development, gonadosomatic index (GSI), and related steroid hormones (testosterone or T, 11-ketotestosterone or 11-KT, 17α, 20β-dihydroxy-4-pregnen-3-one or DHP) in serum were monitored during an annual reproductive cycle in tank-reared, hatchery-bred male catfish Clarias macrocephalus to established the season optimum for its artificial propagation. GSI values were highest in June (0.80%), and lowest in December, February, April (0.36%). At most times of the year, lobules in the testis and seminal vesicles were mostly lined with spermatogonia B (SGb) and spermatocytes (SC) and few spermatogonia A (SGa); spermatids (SD) and spermatozoa (SZ) were the least and most abundant of the spermatogenic cells, respectively. In January however, almost equal counts of SGa, SGb and SC were observed, as well as a significant increase in the percentage of SD and corresponding decrease in SZ. Serum 11-KT fluctuated at high levels, with the lowest level in January (159.42 ng/ml), and peak in September (434.72 ng / ml). Serum T levels ranged from 15-25 ng/ml, and were not markedly different throughout the annual cycle. Serum DHP levels were extremely low in January-May, and reached maximum levels in July (0.18 ng/ ml). Seasonal changes in the percentage of spermatogenic cells, GSI and serum steroid hormone profiles showed that captive, hatchery-bred male C. macrocephalus have a continuous reproductive cycle. Although milt release was not observed, males can readily be used as source of milt for artificial propagation at any time of the annual cycle, except in January.
    • Article

      Threonine requirement of juvenile marine shrimp Penaeus monodon 

      OM Millamena, MN Bautista, OS Reyes & A Kanazawa - Aquaculture, 1997 - Elsevier
      The threonine requirement was determined for juvenile marine shrimp. Penaeus monodon postlarvae, PL20, were stocked in 30-1 fiberglass tanks at ten shrimp per tank arranged in a completely randomized design with six replicates per treatment. They were fed amino acid test diets (40% protein) with casein-gelatin as natural protein sources and supplemented with crystalline L-amino acids to simulate the amino acid profile of shrimp muscle except for threonine. Graded levels of threonine were incorporated to obtain 0.72, 1.0, 1.28, 1.56, 1.84, and 2.12 g per 100 g diet or 1.8, 2.5, 3.2, 3.9, 4.6, and 5.3% of dietary protein. Relationship of weight gain with dietary threonine level was analyzed by the quadratic regression method to derive the threonine requirement. Results showed that the quantitative threonine requirement for growth is 1.4% of the diet or 3.5% of dietary protein. This requirement for growth conforms with the threonine level in the shrimp muscle.
    • Article

      Thyroid hormone surges during milkfish metamorphosis. 

      EG de Jesus - The Israeli Journal of Aquaculture-Bamidgeh, 1994 - Society of Israeli Aquaculture and Marine Biotechnology
      Both thyroxine (T4) and triiodothyronine (T3) were detected in fertilized eggs and larvae of milkfish. The concentration of T4 was lower than that of T3 only in fertilized eggs and newly-hatched larvae. The total body concentrations of both thyroid hormones decreased after hatching. The T4 concentration fluctuated at relatively low levels during the first week after hatching, increased gradually during the next 2 weeks and was highest in 4-week-old larvae. On the other hand, T3 was undetectable in samples taken between days 3 and 11, showed a gradual increase beginning on day 13 and was highest in 27 day old larvae. The concentrations of both T4 and T3 declined again in 31-day-old juveniles. The peak corresponds with the development of silver coloration in hatchery-reared milkfish and the inshore milkfish and the inshore migration of larvae in the wild, suggesting a role for thyroid hormones during early development of this species.
    • Article

      Thyroid hormones promote early metamorphosis in grouper (Epinephelus coioides) larvae 

      EGT de Jesus, JD Toledo & MS Simpas - General and Comparative Endocrinology, 1998 - Academic Press
      The response of grouper larvae to the thyroid hormones, thyroxine (T4) and triiodothyronine (T3), was examined. Two-, 3-, and 4-week-old grouper larvae were reared in seawater containing either T4 or T3 at 0.01, 0.1, and 1 ppm. T4 or T3 induced metamorphosis in all age groups in a dose-dependent manner. Regardless of the size of the larvae, metamorphosis was completed in 2 days in larvae treated with 1 ppm of either T4 or T3; 3–4 days in larvae exposed to 0.1 ppm; and 5–6 days in larvae immersed in 0.01 ppm. None of the fish in the control group completed metamorphosis during this period. Compared with the control fish, survival rates were higher in groups exposed to 0.01 ppm and lower in those exposed to 1 ppm of T3. In 4-week-old larvae, T4 treatment (0.01 to 1.0 ppm) resulted in higher survival compared to the control. These results suggest that a dose of 0.01 ppm is appropriate for acceleration of metamorphosis and improvement of survival in 3- and 4-week-old grouper larvae. A lower dose may be apropriate for earlier stages.
    • Article

      Thyroxine injection of female rabbitfish (Siganus guttatus) broodstock: changes in thyroid hormone levels in plasma, eggs, and yolk-sac larvae, and its effect on larval growth and survival 

      FG Ayson & TJ Lam - Aquaculture, 1993 - Elsevier
      The thyroid hormone levels in female rabbitfish, Siganus guttatus, plasma, eggs, and yolk-sac larvae were measured before and after thyroxine (T4) injection in female spawners at doses of 1, 10, and 100 μg T4/g body weight (BW) fish. T4 and triiodothyronine (T3) levels in maternal plasma, eggs, and yolk-sac larvae were elevated following T4 administration. Apparently, there is conversion of T4 into T3 in the broodfish which suggests the presence of the enzyme, 5′-monodeiodinase, in rabbitfish. T4 and T3 in maternal circulation were easily transferred into the oocytes and subsequently into the larvae. Larvae from spawners treated with 10 and 100 μg T4/g BW tended to be longer and showed sornewhat better survival compared to the control and those injected with 1 μg T4/g BW 7 days after hatching. These findings suggest that thyroid hormones may play an important role during early larval development of rabbitfish.
    • Article

      Tilapia (T. nilotica) and Azolla (A. pinnata) cage farming in Laguna Lake 

      JB Pantastico, SF Baldia & DM Reyes Jr. - Fisheries Research Journal of the Philippines, 1986 - Fisheries Research Society of the Philippines
      Four batches of Azolla were grown in cages in Laguna lake between 1981 to 1983. Percent increase in weight per day ranged from 35% (Feb. 24 - March 2, 1981) to 5% (May 8 - May 12, 1983.) Best growth was attained during the cold months.

      Acceptability of Azolla as supplemental feed for tilapia was determined in four experiments conducted between 1981-1984. The stocking densities varied in the four experiments: 25/m2, 50/m2, 100/m2 and 150/m2. All the results showed increase in mean weight of tilapia fed with fresh Azolla over the unfed control. Statistical analysis showed significantly high (p<0.05) mean weights of tilapia fed with Azolla in two experiments only.
    • Article

      Tilapia cage culture and the dissolved oxygen trends in Sampaloc Lake, the Philippines 

      AE Santiago & RP Arcilla - Environmental Monitoring and Assessment, 1993 - Springer Verlag
      The 28-hectare tilapia cage culture that occupied the 104-hectare Sampaloc Lake, a crater lake, shifted to intensive method in 1986 when tilapia growth slowed done at the beginning of 1982. Thus, commercial feeds became the main source of allochthonous organic matter in the lake. Total feeds given annually for the 28-hectare cage culture at 3 croppings per year amounted to 5250 tons. At feed conversion ratio of 1 : 2 a significant portion of the feeds given ended as organic wastes in the lake. In 1988, tilapia cage operators began experiencing their worst occurrences of fishkill, worth millions of pesos. An assessment of the dissolved oxygen condition of Sampaloc lake in late 1989, 1990 and mid-1991 showed ominous trends which might adversely affect the use of Sampaloc lake for fishery.
    • Article

      Tilapia cage farming in freshwater reservoir using artificial diets during dry and wet seasons 

      DD Baliao & NS Dosado - The Philippine Agricultural Scientist, 2011 - College of Agriculture, University of the Philippines Los Baños
      Netcage culture of Nile tilapia, Oreochromis niloticus L., was conducted in a freshwater reservoir in Dingle, Iloilo, Philippines from February to October 2009 using Test diet (SEAFDEC/AQD) vs. Commercial feed A (Tateh) in the dry season and Test diet vs. Commercial feed B (Hoc Po) in the wet season. Percent crude protein for Test diet, Commercial feed A and Commercial feed B were 34–35%, 27–33% and 25–32%, respectively. Values for crude fat, crude fiber, crude ash and moisture were 6.0–6.5%, 3.5–5.0%, 10–12% and 4–12% for Test diet; 5–7%, 4.0–8.0%, 12% and 12% for Commercial feed A; and 7%, 4%, 12% and 12% for Commercial feed B, respectively. All netcages were stocked with tilapia fingerlings at 15 m-3 with mean initial weight of 1.2 g and 1.3 g during the dry and wet seasons, respectively.

      The fish were fed with floating feeds for 87–89 d of culture. For the dry season, tilapia fed with Test diet had significantly higher (P<0.05) average body weight (ABW, 173.0 ± 1.3 g) and % survival (95.3 ± 2.2%) than Commercial feed A (158.0 ± 0.5 g, 92.0 ± 0.6%). Also, the absolute growth rate (AGR) of 1.97 ± 0.02 g d-1, feed conversion rate (FCR) of 1.29 ± 0.01, final biomass of 154.60 ± 2.4 kg per cage and gross income of PhP 13,914 ± 18 for Test diet-fed tilapia were significantly higher (P<0.05) than those given Commercial feed A. For the wet season, tilapia fed with Test diet were not significantly different (P>0.05) in terms of ABW, survival, AGR, FCR, final biomass and gross income from those fed with Commercial feed B. During the dry season, tilapia fed with Test diet had significantly higher net income compared with those fed with Commercial feed A. There was no significant difference in terms of net income obtained for fish fed with Commercial feed B during the wet season compared with those fed with Test diet. The favorable return on investment (ROI), payback period and production cost per kilogram at 67.83%, 0.62 yr and PhP 46.72, respectively, were also shown by Test diet with a break-even price of PhP 67.55 and a break-even volume of 116 kg per crop. The overall production performance indicated that using cost-effective Test diet with high protein level would be a profitable and sustainable aquaculture venture during the dry season in the Philippines. In the wet season, however, the productive performance of tilapia and the efficiency of artificial feeds tested were relatively the same.
    • Article

      Tissue distribution of mercury and selenium in minnows, Phoxinus phoxinus 

      MLA Cuvin-Aralar & RW Furness - Bulletin of Environmental Contamination and Toxicology, 1990 - Springer Verlag
      The protective effect of selenium against mercury toxicity has been extensively demonstrated in a number of studies (Burke eta]. 1977; Kasuya 1976). Since mercury uptake is not always diminished by the presence of selenium (Kim eta]. 1977) and neither does selenium enhance the elimination of mercury (Lucu and Skreblin i981; Cuvin and Furness 1988), these findings indicate that the mechanism for the observed protective action of selenium against mercury toxicity lie along different lines. It is believed that the rechanelling of mercury from one organ or tissue to another is one of the general mechanisms involved in the protective action of selenium against mercury toxicity. This is supported by the fact that one of the observed effects of selenium treatment on mercury-intoxicated animals is the apparent modification of the distribution pattern of mercury in the different organs and tissues. Decreased mercury levels in the kidney after selenium treatment has been demonstrated in rats by Chen eta]. (1974) and Potter and Matrone (1974).

      The following study aims to determine the effect of selenium on the distribution pattern of mercury in a common freshwater fish, the minnow Phoxinus phoxinus (Order Cypriniformes; Family Cyprinidae). Conversely, the effect of mercury on the tissue distribution of selenium will also be studied.
    • Article

      Tissue lipid content and fatty acid composition during ovarian maturation of ablated Penaeus monodon 

      OM Millamena, RA Pudadera & MR Catacutan - The Israeli Journal of Aquaculture-Bamidgeh, 1993 - Society of Israeli Aquaculture and Marine Biotechnology
      The total lipid content and fatty acid composition in the hepatopancreas, muscle and gonad of ablated Penaeus monodon females at ovarian maturation Stages I to V were examined. The lipid content was highest in the hepatopancreas, 22.5% to 34.9% dry wt. There was no marked variation with maturation stage in muscle lipid levels. Ovarian lipid content more than doubled the initial value of 7.5% at commencement of maturation Stage II, and progressively increased to a maximum of 21.9% at full maturity (Stage IV), corollary to a rise in hepatopancreas lipid. The findings suggest lipids are stored and utilized for gonadal development and spawning. Fatty acid profiles in the tissues showed a predominance of 20:4n-6, 20:5n-3 and 22:6n-3 polyunsaturated fatty acids (PUFA). The characteristically high levels of PUFA in mature shrimp ovaries and presence in spawned eggs are indicative of their metabolic and physiological importance in penaeid shrimp reproduction.
    • Article

      Tissue lipid content and fatty acid composition of Penaeus monodon Fabricius broodstock from the wild 

      OM Millamena & FP Pascual - Journal of the World Aquaculture Society, 1990 - Wiley-Blackwell
      Tissues (hepatopancreas, muscle, gonad) of wild Penacus mordon females with ovaries in different stages of development and males were analyzed for Upid content and fatty acid composition. Hepatopancreatic tissue had the highest mean levels of lipid at 15.72–25.20% in females and averaged 46.20 ± 1.53% in males. Levels of Lipid in the muscle were low with no marked variation throughout the maturation s-es. Ovarian lipid levels increased significantly at stage II (early maturing ovaries) and remained high through stage IV (fully mature ovaries). Peak lipid level was found at stage III (late maturing ovaries) and coincided with a decline in hepatopancreas lipid. Ovarian and hepatopancreatic lipids declined drastically in spent females. Profiles of fatty acid in the tissues consistently showed the presence of PUFA 204n-6, 20:5n-3 and 22611-3, with high levels in the polar lipid fraction of vitellogenic ovaries. These values were reflected in the male testis and spawned eggs. The finding suggest storage and utilization of lipids for maturation and spawning processes and that the phospholipids were mainly responsible for increases in ovarian lipids. The type of fatty acids present in maturing prawn ovaries is indicative of their importance in reproductive physiology.