Now showing items 839-858 of 1075

    • Article

      Quality assessment of newly hatched mud crab, Scylla serrata, larvae 

      ET Quinitio, JJ dela Cruz-Huervana & FD Parado-Estepa - Aquaculture Research, 2018 - Wiley
      Starvation and exposure to formalin were investigated as possible stress tests for evaluating the quality of mud crab, Scylla serrata, larvae. For the starvation stress test, newly hatched zoeae stocked in 150-ml containers were either starved or fed rotifers. Similarly, newly hatched zoeae were stocked in containers with seawater of 0 (control), 20, 30 and 40 mg/L formalin for the formalin stress test. The zoeae from the same batches were used for seed production to monitor their performance and validate the results of stress tests. Starvation was found to be unsuitable for larval quality evaluation. However, the impact of initial food deprivation on the newly hatched larvae indicates that feeding immediately after hatching is necessary for mud crab larvae. Exposure of larvae to 40 mg/L formalin for 3 hr appeared to be a reliable and practical method for larval quality assessment as the survival of larvae in the mass production tanks validated the classification of good and poor quality batches in the stress tests. On this basis, a hatchery operator can decide which batch should be cultured further. Finally, there appears to be a link between the quality of larvae and the performance at the megalopa and early juvenile crabs.
    • Article

      Quality of hatchery-reared juveniles for marine fisheries stock enhancement 

      L Le Vay, GR Carvalho, ET Quinitio, JH Lebata, VN Ut & H Fushimi - Aquaculture, 2007 - Elsevier
      The potential for stock enhancement by release of hatchery-reared juveniles continues to be a topic of interest to researchers and fisheries managers. While, in many studies, the focus has tended to be on the technology for production of juveniles, the need for a more multidisciplinary approach is now becoming accepted. Ideally, this includes studies of population dynamics and recruitment-limitation of wild stocks, environment–stock interactions, habitat availability, genetic studies of wild and released stocks and integration with appropriate fisheries management. While it may be relatively straightforward to culture large numbers of seed animals, the quality of hatchery-reared juveniles may limit the effectiveness of any release programme. The quality of juveniles may be defined either by their ability to attain the age and size to recruit to a commercial fishery or their fitness to survive to contribute to the spawning stock. Many factors will inevitably influence batch–batch variability in the viability of hatchery-reared juveniles and their ability to recruit and compete in the wild. Some effects of nutrition and environment in the hatchery are well-known or at least recognised and their manipulation offers the potential for improvement of survivorship of juveniles post-release. The choice and utilisation of broodstock also represent a crucial stage in enhancement programmes, and considerations of bottleneck effects arising from reduced effective population size due to skewed parental and family contributions must be given careful consideration. A broodstock design that encompasses sufficient numbers of animals that reflect the genetic, and preferably ecological, identity of the stocks to be enhanced should be adopted. In addition, environmental conditions and husbandry practices within the hatchery as well as broodstock and larval nutrition can all influence the quality of offspring. Further conditioning and/or selection during nursery culture may also be critical in maximising the physiological and behavioural fitness of hatchery juveniles post-release. Although evaluation of long-term performance of individual batches of juveniles requires considerable effort or may be impossible in some cases, this type of quantification is likely to be an important component in the determination of the effectiveness of release programmes. This paper reviews the effects of hatchery and nursery practice on larval and juvenile fitness for stock enhancement and presents examples of comparisons of the quality of wild and hatchery-reared juveniles and the effect of pre-release conditioning on subsequent survival and growth.
    • Article

      Quantitative and qualitative analyses of the bacterial microbiota of tilapia (Oreochromis niloticus) cultured in earthen ponds in the Philippines 

      R Pakingking Jr., P Palma & R Usero - World Journal of Microbiology and Biotechnology, 2015 - Springer Verlag
      The quantity and composition of the bacterial microbiota in the rearing water, sediment, gills and intestines of tilapia Oreochromis niloticus collected every 2 weeks from Day 30 to Day 120 after stocking for grow-out culture in 6 earthen brackish water ponds in the Philippines were examined. The total heterotrophic aerobic bacterial counts obtained in the water, sediment, gills and intestines of tilapia ranged from 103 to 104 c.f.u. ml−1, 103–105, 105–107 and 104–107 c.f.u. g−1, respectively. In terms of composition, a total of 20 bacterial genera and 31 species were identified with the preponderance of gram-negative bacteria constituting 84% of all bacterial isolates examined. Aeromonas hydrophila, Bacillus spp., Plesiomonas shigelloides, Shewanella putrefaciens, Pseudomonas fluorescens, Staphylococcus spp. and Vibrio cholerae were the dominant bacteria identified in the gills and intestine of tilapia. These bacteria also dominated in the pond sediment and rearing water, except for the nil isolation of S. putrefaciens and V. cholerae in the water samples examined, indicating that resident bacteria in the pond water and sediment congruently typify the composition of bacterial microbiota in the gills and intestine of tilapia which under stressful conditions may propel the ascendance of disease epizootics.
    • Article

      The quantitative dietary protein requirements of Penaeus monodon juveniles in a controlled environment 

      VR Alava & C Lim - Aquaculture, 1983 - Elsevier
      Penaeus monodon juveniles (average weight = 1.32 g) were kept in individual 2 l perforated plastic containers, 10 of which were placed in each of the twenty-four 50 l rectangular wooden-glass aquaria supplied with seawater filtered through a sand-gravel filter (32–34 ppt; 26.5–29.0°C; pH, 7.6–8.2) at 0.8–1.01 l/min. Eight diets were prepared containing 25–60% protein and fed at 10% of the body weight/day for the first 2 weeks and 8% for the succeeding 4 weeks.

      Shrimps fed the 40% protein diet produced the best growth, feed conversion ratio (FCR), protein efficiency ratio (PER) and survival rate. However, shrimps fed the 30, 35 and 45% protein diets produced comparable results. The protein content of the shrimps was directly related to the level of protein diet up to 50%; whereas fat content seemed to be inversely related up to 50% protein diet.
    • Article

      Quantitative dietary requirements of postlarval tiger shrimp, Penaeus monodon, for histidine, isoleucine, leucine, phenylalanine and tryptophan 

      OM Millamena, MB Teruel, A Kanazawa & S Teshima - Aquaculture, 1999 - Elsevier
      The quantitative requirements of postlarvae Penaeus monodon for essential amino acids were determined through a series of feeding experiments. Test diets contained casein–gelatin as natural proteins supplemented with crystalline L-amino acids (CAAs) at levels based upon the tissue amino acid profile of postlarvae tiger shrimp. Each set of experimental diets contained graded levels of the test amino acid in a range below and above those found in shrimp muscle protein. The dietary CAA mixture was pre-coated with carboxymethylcellulose (CMC), and the diets were additionally bound with CMC, corn starch, and K-carrageenan to prevent leaching of amino acids and other nutrients. P. monodon postlarvae, PL20, mean body weight of 20 mg, were randomly distributed to 30-l fiberglass tanks at a density of 10/tank and each group was fed a particular diet for 56 days. A one-way analysis of variance was used to determine if there were any significant differences in weight gain, survival, and feed conversion among the dietary treatments for each experiments. Regression analysis of the weight gain responses against dietary amino acid levels was used to estimate the amino acid requirements. The optimum dietary requirements for essential amino acids, in percent of the diet, were: 0.8% histidine, 1.01% isoleucine, 1.7% leucine, 1.4% phenylalanine, and 0.2% tryptophan. Expressed as percent of the dietary protein, the requirement values were: 2.2% histidine, 2.7% isoleucine, 4.3% leucine, 3.7% phenylalanine, and 0.5% tryptophan. This information is crucial in optimizing growth and feed efficiency and in developing cost-effective diets for P. monodon.
    • Article

      Quantitative lysine requirement of milkfish (Chanos chanos) juveniles 

      IG Borlongan & LV Benitez - Aquaculture, 1990 - Elsevier
      A feeding experiment was conducted to determine the quantitative dietary requirement of milkfish juveniles for lysine. Milkfish (Chanoschanos Forsskal) of mean weight 5.92±0.14 g were fed diets containing 7.0, 11.0, 15.0, 19.0, 23.0 and 27.0 g lysine/kg dry diet for 12 weeks. The amino acid test diets contained white fish meal and zein supplemented with crystalline amino acids to provide an amino acid profile similar to milkfish proteins except for lysine. Each of the six diets was fed to four replicate groups of 25 fish in a completely randomized design and at a feeding rate of 5% of the fish body weight per day. On the basis of the growth response, lysinerequirement of juvenile milkfish was found to be 20 g/kg diet. This value corresponds to 4.0% when expressed as a percentage of the dietary protein. Survival (94–97%) was consistently high in all treatments. Except for loss of appetite resulting in low food intake and depressed growth, no nutritional deficiency signs were observed in fish given the lysine-deficient diets.
    • Article

      Rapid rural appraisal and participatory research in the Philippines 

      WG Gallardo, VC Encena II & NC Bayona - Community Development Journal, 1995 - Oxford University Press
      Rapid Rural Appraisal (RRA) was conducted in the fishing village of Lakaran, in the municipality of Dumangas, Iloilo province to identify the resources, livelihood, problems, opportunities, and socioeconomic condition of the villagers prior to the conduct of farmer participatory research on mussel farming. RRA tools such as the construction of the village transect, seasonal calendar and wealth ranking were used.
    • Article

      Rapid wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid 

      G Erazo-Pagador & MS Din - The Israeli Journal of Aquaculture-Bamidgeh, 2001 - Society of Israeli Aquaculture and Marine Biotechnology
      Wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid was studied under laboratory conditions. Fish weighing approximately 80-110 g were stocked in 500 l aquaria in a static water system and fed one of five test diets containing different levels of microencapsulated ascorbic acid (0, 0.06, 0.10, 0.30 and 0.70 g AsA/100 g feed). After two weeks, all experimental fish were wounded by making a 1 x 1 cm dorso-lateral incision above the lateral line of the fish. Wounded tissues were sampled for histopathological analysis 4, 8, 24, 48 and 96 hours, 6, 8, 10, 12 and 14 days after making the incision. There were significant differences in weight gain, specific growth rate (SGR) and feed conversion ratio among the dietary treatments. Weight gain and SGR of fish fed the ascorbic acid free diet were lower than those of fish fed diets supplemented with ascorbic acid. The wound healing response showed a direct correlation to ascorbate level in the diet. Fibroblasts were present at 96 h irrespective of the ascorbic acid level. As 14 days, fish fed no ascorbic acid had some regeneration of muscle tissues, whereas fish fed diets containing supplemental ascorbic acid had a normal epidermis, dermis and muscle structure. There was no mortality during the experimental period, and fish fed ascorbic acid free diets did not exhibit any deficiency signs. Results of this study indicate that about 0.10-0.70 g AsA/100 g feed is needed for wound repair in African catfish.
    • Article

      Rearing of the larval stages of prawn, Penaeus japonicus Bate, using artificial diet. 

      CT Villegas & A Kanazawa - Memoirs of the Kagoshima University Research Center for the South Pacific, 1980 - Kagoshima University Research Center for the South Pacific
      Survival and growth rates of the zoeal and mysis stages of the prwn, Penaeus japonicus Bate, were studied using natural and artificial diets.

      The highest survival rate, 34.2%, was obtained in the larvae fed with the artificial diet, Diet-B. Larvae fed with the diatom, Chaetoceros gracilis, plus Artemia nauplii did not give the best survival; however, growth was the fastest in this group. The larvae metamorphosed into the mysis3 stage in 8 days. The results thus seem to demonstrate tat Diet-B is an effective diet for the early larval stages of the prawn, P. japonicus.
    • Article

      Reducing and managing disaster risk through coastal resource management: A Philippine case 

      JGB Suyo, A Prieto-Carolino & RF Subade - Asian Fisheries Science, 2013 - Asian Fisheries Society
      Recently, disaster risk reduction and management was adopted by the national and local governments in the Philippines to prevent or mitigate the impacts of hazards. As a consequence, the Local Government Units of the coastal municipalities of Guimbal and Tigbauan, Iloilo Province, initiated disaster risk reduction and management activities. It is contended in this article that the condition of coastal and marine resources is fundamental in fostering community resilience to hazards, as exemplified by activities in Guimbal and Tigbauan. However, five major issues that remain to be addressed by the Local Government Units were identified through Key Informant Interviews and Focus Group Discussions. These include the overlapping roles of personnel, poor data management, weak coordination between Local Government Units and communities, lack of comprehensive plans, and a failure to understand the connection between disasters and the management of coastal and marine resources. Policy recommendations are made for amending the disaster risk reduction and management and coastal and marine resources programmes of municipalities.
    • Article

      Relationship between diet composition and growth rate of the zoeal and mysis stages of Penaeus japonicus Bate 

      CT Villegas & A Kanazawa - Fisheries Research Journal of the Philippines, 1979 - Fisheries Research Society of the Philippines
      Feeding experiments were conducted on Penaeus japonicus larvae using Chaetoceros gracilis plus Artemia nauplii, an artificially prepared diet (Diet-B), and two commercial feeds (Tapes and mysid meals) in a randomized complete block design with two replicates per diet. The artificially prepared diets were dried and ground to size 10 to 50 microns and fed to the larvae. The larvae were reared in round plastic aquaria each containing 5 liters of filtered seawater. Each aquarium was stocked with 250 larvae and provided with aeration. The larvae were reared from zoea (Z1) to mysis (M3) stage and growth was measured daily.

      The highest survival rate of 34.2% was obtained when the larvae were fed with Diet-B. C. gracilis plus Artemia nauplii feeding gave a survival rate of 21.6%. On the other hand, growth measured in terms of development, was fastest using C. gracilis plus Artemia nauplii. Larvae metamorphosed into stage in 7 days with an average gain in length of 0.46 mm/day. Diet-B feeding resulted in a comparable growth, the larvae reaching M3 stage in 8 days with an average gain in length of 0.30 mm/day. Analyses of the chemical composition of the diets showed no definite relationship between diet composition and growth and survival rates of the early larval stages of P. japonicus.

      Results obtained in this study demonstrate that the early larval stages of P. japonicus can be reared with feeding of Diet-B. Since the chemical composition of the diet is known, it can be used as supplemental data for larval feed development and nutritional requirements studies for the early larval stages of P. japonicus and/ or other penaeids.
    • Article

      Replacement of fish meal by animal by-product meals in a practical diet for grow-out culture of grouper Epinephelus coioides 

      OM Millamena - Aquaculture, 2002 - Elsevier
      A feeding trial was conducted to evaluate the potential of replacing fish meal with processed animal by-product meals, meat meal and blood meal (4:1 ratio), in practical diets for juvenile grouper (Epinephelus coioides). Eight isonitrogenous diets were formulated to contain 45% protein and 12% lipid. Fish meal was replaced by 0%, 10%, 20%, 30%, 40%, 60%, 80%, and 100% of meat meal and blood meal (4:1) mixture (diets 1–8). The diet with 100% fish meal (diet 1) or trash fish as feed (diet 9) were used as controls. Grouper juveniles were reared in 250-l circular fiberglass tanks maintained in a flow-through seawater system. Each dietary treatment was tested in quadruplicate groups of 25 fish per tank arranged in a completely randomized design. Fish were fed the diets twice per day at a daily feeding rate of 5–6% of biomass and trash fish at 10–12% of biomass for 60 days. Percentage weight gain, specific growth rate (SGR), survival, feed conversion ratio (FCR) and body composition of grouper juveniles were measured. There were no significant differences (P>0.05) in growth performance among fish fed diets 1–7 (0–80% fish meal replacement) with those fed diet 9 (trash fish as feed). However, fish fed diet 3 had significantly higher (P<0.05) growth than those fed diet 8 (100% fish meal replacement). Survival among fish fed the experimental diets did not significantly differ (96–100%) but was significantly higher (P<0.05) than survival (90%) of fish fed trash fish. These results showed that up to 80% of fish meal protein can be replaced by processed meat meal and blood meal coming from terrestrial animals with no adverse effects on growth, survival, and feed conversion ratio of E. coioides juveniles.
    • Article

      Reproductive development of the threatened giant grouper Epinephelus lanceolatus 

      The giant grouper is presumed to follow the reproductive pattern of most Epinephelus species, characterized by protogynous hermaphroditism wherein male maturation is attained through sex reversal of a functional female. This hypothesis, however, has not been verified due to lack of biological data. The present study addresses this gap by investigating the reproductive development of giant groupers from juvenile stage through sexual maturity. Gonad histological analysis of hatchery-bred juvenile giant grouper from Queensland, Australia (0.8–5.2 kg, n = 43) have shown earliest occurrence of primary oocytes (i.e. ovarian differentiation) in 47.8 cm and 2.5 kg fish. Monitoring of sexual maturity by gonadal biopsy was performed in a stock of wild-caught giant groupers (2–52 kg) held in sea cages in the Philippines and Vietnam from 2015 to 2017. Onset of female sexual maturity was at 96.9 ± 1.6 cm and 23.5 ± 1.5 kg in the Philippines, and 103.0 ± 4.1 cm and 33.5 ± 2.5 kg in Vietnam. In both locations, development of primary males was observed wherein fish produced milt (or spermiated) without passing through a functional female phase. The ratio of primary males to females in both locations was about 1:2. Size at maturity of primary males is 86.5 ± 4.8 cm and 17.1 ± 2.1 kg in the Philippines, and 97.3 ± 1.3 cm and 34.3 ± 0.9 kg in Vietnam. To aid in the monitoring of female maturation, we developed a non-invasive method based on immunoassay of vitellogenin in skin mucus and this was shown to be effective in detecting female maturation 9 ± 2 months prior to first observation of oocytes through gonadal biopsy. Our findings suggest that giant grouper is a diandric protogynous hermaphrodite. This study provides novel information on the reproductive biology of giant grouper, an economically important and vulnerable species.
    • Article

      Reproductive performance and growth of Nile tilapia (Oreochromis niloticus) broodstock fed diets containing Leucaena leucocephala leaf meal 

      CB Santiago, MB Aldaba, MA Laron & OS Reyes - Aquaculture, 1988 - Elsevier
      The effects of dietary leucaena leaf meal on reproductive performance and growth of Nile tilapia were determined. In the preliminary trial, sexually mature Nile tilapia were fed with a control diet or a test diet which had leucaena leaf meal as the only protein source for 24 weeks. Fish fed with the leucaena diet lost some weight and had significantly low (P<0.05) gonadosomatic index and fry production compared to those fed with the control diet. Subsequently, four isonitrogenous diets (20% crude protein) containing varying amounts of leucaena leaf meal (0, 20, 40 and 80%) were fed to Nile tilapia broodstock. Mean weight gain of the female fish decreased as the level of leucaena leaf meal in the diets increased. Females fed with the 80% leucaena diet invariably lost weight. Mean weight gain of males fed with the control diet and the 20 and 40% leucaena diets did not differ significantly (P>0.05). However, growth of males fed with the 80% leucaena diet was remarkably low. Fry production was highest for those fed with the control diet and the 20% leucaena diet. Fry production decreased slightly in fish fed with the 40% leucaena diet and was significantly low (P<0.05) for those fed with the 80% leucaena diet. The low fry production was preceded by a decrease in body weight of the female fish. However, the gonadosomatic indices of the females and the males were not markedly affected by the diets. On the basis of both fry production and growth, leucaena leaf meal should not exceed 40% of the diet of Nile tilapia broodstock.
    • Article

      Reproductive performance and larval quality of pond-raised Scylla serrata females fed various broodstock diets 

      OM Millamena & JB Bangcaya - Asian Fisheries Science, 2001 - Asian Fisheries Society
      Scylla serrata females with initial body weight (BW) of 350 to 400 g were previously raised on a defined diet of 75% brown mussel meat and 25% fish bycatch in grow-out ponds at Molo, Iloilo City, Philippines for 120 days. Crabs were stocked in three units of 4 m diameter concrete indoor tanks at the Crustacean Broodstock Wet Laboratory of SEAFDEC Aquaculture Department in Tigbauan, Iloilo, Philippines. Tanks had sand substrates and were supplied with sand-filtered and chlorinated seawater in a continuous flow-through system with adequate aeration. Each female was provided with individual shelter. Before stocking, crabs were tagged on their carapace and half of the females were ablated while the other half remained intact. Broodstock were fed either T1, natural food consisting of mussel and fish bycatch; T2, a mixed diet of natural food and formulated diet; or T3, a formulated diet. Broodstock reproductive ability was measured as percent spawnings, spawnings with hatching, fecundity or number of eggs per g BW of female, egg fertilization rate and total zoea produced. Larval quality was measured as larval stage index or ability to attain the megalopa stage, the highest larval stage. Females fed on all dietary treatments were capable of maturation and spawnings. However, mixed diet feeding (T2) improved broodstock performance and larval quality over those fed either natural food (T1) or formulated (T3) alone. Eyestalk ablation improved fecundity and produced higher total zoea in T1 and T3 although lower in egg fertilization rate than intact females. All zoea larvae in ablated T2 females were successfully reared to megalops. Overall improvement in larval quality of both ablated and intact females compared with previous studies on wild-caught females was attributed to their dietary history in grow-out ponds. Feeding the females with a suitable diet in ponds enabled them to fortify the reserves of nutrients needed for egg development and improve stability in larval production.
    • Article

      Reproductive performance in induced and spontaneous spawning of the mangrove red snapper, Lutjanus argentimaculatus: a potential candidate species for sustainable aquaculture 

      AC Emata - Aquaculture Research, 2003 - Blackwell Publishing
      A reliable breeding technique was developed for the mangrove red snapper, Lutjanus argentimaculatus (Forsskal 1775), to help sustain the aquaculture of this immensely popular species in Southeast Asia. Using standardized indices of female maturity (based on mean oocyte diameter of ≥0.40 mm), time of injection (1000–1130) and sex ratio (one female to two males), a single injection of 100 μg kg−1 luteinizing hormone-releasing hormone analogue (LHRHa) (n=16 fish), but not 50 μg kg−1 (n=five fish), successfully induced egg (62.5% success rate) and larval (43.8%) production. Human chorionic gonadotropin (hCG) at 500 IU kg−1 (n=five fish) also failed to induce spawning, but doses of 1000 (n=22 fish) and 1500 IU kg−1 (n=15 fish) gave spawning (77.3% and 80.0% respectively) and hatching success rates (72.7% and 60.0% respectively) that were not significantly different from those of 100 μg kg−1 LHRHa. No spawning was observed in saline-injected controls (n=seven fish). While mean spawning latency, egg diameter, egg production per spawn, percent egg viability, hatching rate, percent of normal larvae and cumulative survival of eggs to normal larvae did not differ significantly among the effective hormones and doses, 1000 IU kg−1 hCG had a higher percentage (76.5%) of total spawns with egg production per spawn in excess of one million than those of 1500 IU kg−1 hCG (50.0%) and 100 μg kg−1 LHRHa (40.0%). Mangrove red snapper spontaneously spawned from March–April to November–December with a peak of egg collection and spawning in May–June. Egg collection per spawn ranged from 0.05 to 6.35 million. Spontaneous spawning of mangrove red snapper exhibited lunar periodicity with spawns mostly occurring 3 days before or after the last quarter and new moon phases and occurred consistently between 02:00 and 04:00 hours. High fecundity and good egg quality, coupled with the ability to respond to induce spawning or natural spawning in captivity, provide a sound basis for improving the sustainability of red snapper aquaculture in Southeast Asia.
    • Article

      Reproductive performance of four red tilapia strains in different seed production systems 

      MRR Eguia - The Israeli Journal of Aquaculture-Bamidgeh, 1996 - Society of Israeli Aquaculture and Marine Biotechnology
      The reproductive efficiency of one Thai red tilapia strain (NIFI) and three genetically diverse Philippine red tilapia strains (BFS, FAC, and PF) were compared. Breeders from each strain were stocked separately in land-based concrete tanks and lake-based hapa net cages or fine-meshed net cages at densities of 4 males:12 females per enclosure. Spawning activity, seed (egg and fry) production and hatchability data from the four strains in each hatchery system were monitored once every three weeks for twelve months.

      Results showed that seed production in all strains was lower in cages than in tanks. Daily mean seed production in the land-based hatchery system was highest at 12.41 per spawner for FAC followed by NIFI (11.18), BFS (9.49) and PF (5.56). In the hapa net cages, BFS produced 2.19 eggs and fry per female daily while NIFI, FAC and PF gave daily harvests of 1.40, 1.18 and 1.14 eggs and fry per spawner. Analysis of variance showed that seed production was significantly influenced by the strain, type of hatchery system and the interaction between the two factors.
    • Article

      Reproductive performance of hatchery-bred donkey's ear abalone, Haliotis asinina, Linne, fed natural and artificial diets 

      MN Bautista-Teruel, OM Millamena & AC Fermin - Aquaculture Research, 2001 - Blackwell Publishing
      Hatchery-bred donkey's ear abalone, Haliotis asinina, Linne broodstock were given diets consisting of natural food, seaweed (SW), Gracilariopsis bailinae, D1; combination of SW and artificial diet (AD), D2; and AD alone, D3. Equal numbers of 1 : 1 female and male abalone were stocked in 24 units, 60 L tanks with eight replicate tanks per dietary treatment. Reproductive performance, e.g. number of spawnings, instantaneous fecundity and egg hatching rates, was monitored over 270 days. The mean number of spawnings was not significantly different among treatments. The mean instantaneous fecundity and percent hatching rates were significantly higher in abalone fed D2 or D3 compared to those given D1. Survival of abalone broodstock fed D1 was, however, significantly higher at 88% than those fed either D2 or D3 at 75%. Fatty acid analysis showed that the n-3/n-6 fatty acid ratios of abalone hepatopancreas reflected those of their diets. Mature abalone ovary had n-3/n-6 fatty acid ratio of 1.3. A higher amount of essential nutrients in the artificial diet such as protein, lipid and the highly unsaturated fatty acids, e.g. 20 : 4n-6, 20 : 5n-3, 22 : 6n-3 in abalone fed D2 or D3, may have influenced the increased reproductive performance.
    • Article

      Reproductive performance, lipids and fatty acids of mud crab Scylla serrata (Forsskål) fed dietary lipid levels 

      VR Alava, ET Quinitio, JB de Pedro, ZGA Orosco & M Wille - Aquaculture Research, 2007 - Blackwell Publishing
      Natural food (NF, control), artificial diets (AD) containing total lipid levels of 10%, 12% and 14% (AD10, AD12 and AD14) and their combinations (AD10+NF, AD12+NF and AD14+NF) were fed for 112 days to pond-sourced eyestalk-ablated mud crab Scylla serrata (625±6.4 g) in tanks in order to determine their effects on reproduction and lipid profiles in broodstock tissues and zoeae. Crabs fed NF had the highest number of spawning followed by crabs fed AD10+NF and AD14+NF. Higher offspring production (number of zoeae) was obtained from crabs fed NF and AD+NF than from AD. As dietary total lipid levels increased, total lipid of broodstock ovaries, hepatopancreas, muscle and zoeae correspondingly increased in which AD+NF promoted higher levels than AD. Increased dietary total lipid levels enhanced lipid classes such as triacylglycerols and phosphatidyl choline levels in zoeae, all higher in crabs fed AD+NF than in AD. The major fatty acids in zoeae, particularly 16:0, 18:0, 18:1n-9 and 20:4n-6, 20:5n-3 and 22:6n-3, were higher in crabs fed AD+NF than in AD, the contents corresponding to broodstock dietary total lipid levels. A 10% total lipid in AD in combination with NF was sufficient to provide the essential lipids in crabs in the improvement of larval production and quality.
    • Article

      Reproductive quality of male Penaeus monodon 

      LAO Gomes & J Honculada-Primavera - Aquaculture, 1993 - Elsevier
      The reproductive performance of unilaterally eyestalk-ablated wild male Penaeus monodon was compared with that of unablated prawns (controls). After being stocked for 6 weeks in flow-through tanks, ablated males showed significantly higher sperm count (153.6 × 106 vs.77.5 × 106), less abnormal sperm (45.5% vs 73.3%), larger sperm head diameter (6.682 μm vs. 5.568 μm) and longer spike (5.096 μm vs. 4.360 μm) compared to unablated ones. Gonad index, spermatophore weight and percentage of live sperm were not significantly different between ablated and unablated males. No apparent decline in reproductive capacity was detected when comparing unablated prawns at the start of the study and after 6 weeks.