Now showing items 1-11 of 11

    • Book

      Breeding and seed production of the giant freshwater prawn (Macrobrachium rosenbergii) 

      MLA Cuvin-Aralar, MA Laron, EV Aralar & UC de la Paz - 2011 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension manual; No. 52
      An extension manual describing biology, broodstock management, hatchery and nursery operations, feeding management, packing and transport, and health management of the giant freshwater prawn.
    • Article

      Culture of Macrobrachium rosenbergii (De Man 1879) in experimental cages in a freshwater eutrophic lake at different stocking densities 

      ML Cuvin-Aralar, EV Aralar, MA Laron & W Rosario - Aquaculture Research, 2007 - Blackwell Publishing
      Macrobrachium rosenbergii (de Man 1879) juveniles (0.4 g) were cultured in experimental cages (L × W × H: 2.5 × 1 × 1 m) in Laguna de Bay, the largest lake in the Philippines. The following stocking densities at four replicates each were used: 15, 30, 60 and 90 prawns m−2 of cage bottom. The mean sizes at harvest after 5 months of culture ranged from 14.3 g for the highest stocking density to 26.3 g for the lowest. The mean size at harvest, daily growth rate and size class distribution were significantly influenced by stocking density, with those at the lowest stocking density showing significantly better growth and overall proportion of larger prawns. Heterogeneous individual growth (HIG) was fairly evident in all treatments. The percentage of blue-clawed males was not influenced by treatment but the mean weight was significantly higher in the lower stocking densities. Both the percentage and mean weight of berried females were significantly higher in the lowest stocking density. Survival was the highest in the lower stocking densities (55.3%, 54.0%, 52.7% and 36.9% for 15, 30, 60 and 90 prawns m−2 respectively). Feed conversion ratio (FCR) improved with decreasing stocking density, ranging from 2.1 to 3. As expected, yield per cropping increased with stocking density and ranged from 450 to 1089 g m−2 yr−1 of actual cage area. Production values obtained in the cage cultured M. rosenbergii were comparable to or even higher than those reported from pond culture, given that the stocking densities used in this study were generally higher than in ponds. The results show that the farming of M. rosenbergii in cages in lakes is a viable alternative to pond culture and has the potential of improve aquaculture production in lakeshore fish farming communities.
    • Article

      Dietary crude protein requirement of Tilapia nilotica fry 

      CB Santiago, M Bañes-Aldaba & MA Laron - Kalikasan: The Journal of Philippine Biology, 1982 - University of the Philippines at Los Baños
      Tilapia fry were stocked at three per liter in wooden tank compartments or glass aquaria filled with 50 or 35 l of fresh water in three separate feeding trials. The fry were fed isocaloric practical diets containing 20, 25, 30, and 35% crude protein at 15% of fish biomass daily for seven weeks in the first tow trials. Another set of diets containing 20, 25, 30, 35, 40, 45, and 50% crude protein were fed to fry for eight weeks in trial 3.

      Although treatment means were not significantly different (P< 0.05), weight gains of the fry in trials 1 and 2 were related directly to increasing crude protein levels up to 35%. Weight gain in trial 3, however, was significantly high (P < 0.05) at 35% protein level. Moreover, maximum increases in total length and most efficient feed conversions were invariably attained at 35% protein. Higher protein levels gave much poorer growth. Survival rate at 35% protein was significantly high (P < 0.05) compared to 20% (trial 1) or 30% (trial 2) protein level. In trial 3, survival at 35% protein was not significantly different from all other treatments. Maximum growth, best feed conversion, and high survival were attained with the 35% protein diets.
    • Article

      Effects of human chorionic gonadotropin (hCG) and handling stress on spermiation of silver perch Leiopotherapon plumbeus (Kner, 1864) 

      PJT Denusta, EGT de Jesus-Ayson, MA Laron & LMB Garcia - Journal of Applied Ichthyology, 2014 - Wiley
      This study determined the effect of human chorionic gonadotropin (hCG) and handling stress on the spermiation and milt response of silver perch Leiopotherapon plumbeus based on the measurement of spermatocrit, sperm density, and milt production. Compared to saline-injected fish, the mean spermatocrit (or packed sperm) of hCG-treated fish was significantly lower at 18 h (47.9%) and 30 h (40.2%) post-injection while mean sperm density was significantly lower at 30 h post-injection (3.6 × 106 cells μl−1) but not at 18 h. At 18 h (1.8 μl g-BW−1) and 30 h (2.5 μl g-BW−1) post-injection, mean milt production of hCG-treated fish was significantly higher than in the saline group. Milt consistency was also thinner in the hCG-treated group. Mean sperm density of handled fish (18.0 × 106 cells μl−1) was significantly lower than control fish (23.4 × 106 cells μl−1). However, mean sperm density of handled plus saline-injected (16.2 × 106 cells μl−1) and handled plus hCG-treated fish (8.4 × 106 cells μl−1) was significantly lower than in the control goup. Having thicker milt consistency, mean spermatocrit and milt production of handled (77.5%; 1.1 μl g-BW−1, respectively) and handled plus saline-injected fish (75.4%; 1.1 μl g-BW−1, respectively) were not significantly different from the control fish (76.2%; 1.3 μl g-BW−1, respectively). Handled plus hCG-treated fish had the lowest mean sperm density (8.4 × 106 cells μl−1) and spermatocrit (54.7%), but had the highest mean milt production (5.5 μl g-BW−1) among the treatment groups. These results demonstrate that the hCG injection effectively induces spermiation and milt expression and that handling-related stress negatively affects such responses. The spermatocrit method may be used to assess the spermiation and milt response of silver perch.
    • Conference paper

      Evaluation of different live food organisms on growth and survival of river catfish, Mystus nemurus (C&V) larvae 

      MA Laron, MS Kamarudin, FM Yusoff & CR Saad - In CI Henry, G Van Stappen, M Wille & P Sorgeloos (Eds.), Larvi 2001 : 3rd Fish & Shellfish Larviculture Symposium, Gent, Belgium, September 3-6, 2001, 2001 - European Aquaculture Society
      Series: Special Publication No. 30
      Mystus nemurus is one of the most commercially important freshwater fish in Malaysia. Even though artificial breeding or reproduction of M. nemurus is done in private hatcheries around Peninsular Malaysia, inadequate seed supply coupled with relatively high fingerling prices limits its production. Presently, the supply of fingerlings cannot satisfy the demand for fish farming due to some constraints on the larval rearing, so larval rearing of M. nemurus has yet to be improved in terms of nutrition requirement and suitable size of food for the larvae.

      At present, the conventional method of fish larviculture using live food such as Artemia nauplii is being practiced by most Malaysian catfish hatchery operators. Using expensive live food like Artemia has made the mass production of catfish fry/fingerlings less profitable. Alternative measures are necessary in order to help minimize importation and use of Artemia. Indigenous species of live food organisms, which are great potential as feed and can easily be cultured and mass-produced at low cost, may be used as substitutes. Studies on those live foods are lacking, hence this study was conducted to determine the effect of different live foods on growth and survival of Mystus nemurus larvae.
    • Article

      Growth and fry production of Nile tilapia, Oreochromis niloticus (L.), on different feeding schedules 

      CB Santiago & MA Laron - Aquaculture Research, 2002 - Blackwell Publishing
      The effect of scheduled use of high-protein and low-protein diets on body weight and fry production of Nile tilapia, Oreochromis niloticus (L.), was determined. A preliminary feeding trial was first conducted on fingerlings. These were fed a high-protein diet (H, 25% protein) or a low-protein diet (L, 18% protein) daily, or diet H for 1–3 days followed by diet L for 1–4 days. Final body weight was significantly higher (P < 0.05) in fish fed diet H daily and in fish fed diet H for 2–3 days followed by diet L for 1 day (2H−1L and 3H−1L). Fingerlings on 1H−1L and 3H−2L had slightly lower growth. Based on the response of the fingerlings, five feeding schedules were tested with the broodstock. A high-protein diet (HP, 40%) and a low-protein diet (LP, 25%; same as H for fingerlings) were used. Feeding schedules significantly influenced body weight of female but not the male fish. Fry production was not significantly affected by the feeding schedule for broodstock. When growth, fry production and saving in feed cost were all considered, the broodstock on 1HP−1LP and 3HP−2LP feeding schedules both gave the highest overall performance. These findings give fish farmers an option in the management of feeding of tilapia broodstock.
    • Conference paper

      Growth response and carcass composition of red tilapia fry fed diets with varying protein levels and protein to energy ratios 

      CB Santiago & MA Laron - In SS De Silva (Ed.), Fish Nutrition Research in Asia. Proceedings of the Fourth Asian Fish Nutrition Workshop, 3-8 September 1990, Vijayawada, Andhra Pradesh, India, 1991 - Asian Fisheries Society
      An 8-week feeding experiment was conducted with red tilapia (Oreochromis ) fry of 0.160 plus or minus 0.035 g initial weight. Twelve diets of 4 protein levels (25, 30, 35 and 40%) and 3 protein to energy (P/E) ratios (111, 100 and 80 mg protein/kcal) at each protein level were used. The highest growth was attained by fry fed a 40% protein diet with a P/E ratio of 111 mg/kcal. A lower but not a significantly different growth response was attained by fry on a 35% protein diet with a P/E ratio of 111 mg/kcal and a 30% protein diet with a P/E ratio of 100. Protein efficiency ratio was affected by the dietary protein level. Feed conversion ratio was not significantly influenced by the dietary protein level nor the P/E ratio. Carcass moisture content (%) was affected only by the P/E ratio. Carcass moisture content was directly related to the P/E ratio of the diets and was inversely related to the digestible energy (DE) level. Both protein level and P/E ratio significantly influenced carcass lipid content (%) on a dry matter basis but not the ash content. Carcass lipid (5) increased with increasing dietary protein and increasing DE levels of the diet, but decreased with increasing P/E ratio. Carcass protein content decreased significantly with the decrease of P/E ratio and increase of DE level of the diet.
    • Article

      Larval and early juvenile development of silver therapon, Leiopotherapon plumbeus (Actinopterygii: Perciformes: Terapontidae), reared in mesocosms 

      FA Aya, MNC Corpuz, MA Laron & LMB Garcia - Acta Ichthyologica et Piscatoria, 2017 - Szczecińskie Towarzystwo Naukowe
      The silver therapon, Leiopotherapon plumbeus (Kner, 1864), is an endemic and economically important freshwater food fish in the Philippines. The natural populations of this species have been declining during the past years, mainly due to intense fishing pressure, habitat degradation, and introduction of invasive alien species. At present, it is considered a target species for domestication and conservation efforts. Despite several attempts of artificial reproduction and larval rearing, little is known on larval and early juvenile development of silver therapon. The presently reported study was therefore intended to fill this gap in the knowledge by determining the growth and describing body proportions, pigmentation, and fin formation of this fish. Newly hatched larvae were reared in mesocosm tanks at a mean temperature of 29.5°C. Larvae up to 30 days after hatching were sampled at irregular intervals and preserved in 5% buffered formalin. Early development stages for 245 preserved specimens were described in detail with reference to changes in morphology, growth and body proportions, pigmentation, and fin formation. Five developmental stages of silver therapon were identified: yolk sac larva (1.88 mm TL), preflexion (2.51 mm TL), notochord flexion (4.50-8.27 mm TL), postflexion larva (6.90-12.21 mm TL), and early juvenile (>13.40 mm TL). Growth was isometric for eye diameter and gape size whereas positive allometry was observed for body depth, head length, and preanal length. Some body proportions showed abrupt changes from preflexion to postflexion larvae before it stabilized during the early juvenile stage. Pigmentation in the form of stellate and punctate melanophores increased with developmental stage, with larvae becoming heavily pigmented from postflexion to early juvenile stage. These morphological changes, together with the full complement of fin rays and squamation observed in specimens larger than 13.4 mm TL, suggest the attainment of the juvenile stage of this species. These morphological changes may explain the food and feeding habits during the early life stages of silver therapon which is critical to their survival and recruitment in the wild and in a mesocosm hatchery environment.
    • Article

      Multiple gonadal maturation and re-maturation after hormone-induced spawning in bighead carp Aristichthys nobilis Rich. 

      AC Fermin, MA Laron & DM Reyes Jr. - The Philippine Scientist, 1991 - San Carlos Publications, University of San Carlos
      Gonadal maturation and rematuration after hormone-induced spawning in cage-reared female bighead carp Aristichthys nobilis were observed. Percent maturation ranged from 54 to 100% for females and 0 to 40% for males. Maturation rates in either sex were high during March (1988) and low during December (1987). No significant differences were observed for monthly mean oocyte diameters ranging from 1.41 to 1.51 mm. Of the 34 females injected with LHRH-a, Domperidone or HCG, either singly or in combinations, 12 females spawned successfully. Three females were spawned twice consecutively at intervals between 71 and 107 days. Fish possessed oocytes of similar characteristics as those obtained from pre-spawning females when sampled after 27 days from spawning. Generally, oocyte diameters of individual fish measured before the first spawning (range: 1.41 to 1.53 mm) were not significantly different from those measured during the succeeding spawnings (range: 1.38 to 1.49 mm). Physico-chemical and biological parameters in the lake did not influence maturation except for zooplankton.
    • Book chapter

      On-farm feed management practices for Nile tilapia (Oreochromis niloticus) in the Philippines 

      MRR Romana-Eguia, MA Laron & MR Catacutan - In MR Hasan & MB New (Eds.), On-farm feeding and feed management in aquaculture, 2013 - Food and Agriculture Organization
      Series: FAO fisheries and aquaculture technical paper; No. 583
      The contribution of the Philippines to tilapia production in Asia has increased steadily in the past five years as it addresses hunger and poverty alleviation in the region. Commercial tilapia aquaculture in the Philippines has improved as farmers have become aware of the importance of adopting innovative husbandry technologies. These include the use of intensive culture, using novel feed ingredients, improving the quality of industrial aquafeeds, adopting cost- effective feeding strategies and efficient pond fertilization methods, and culturing improved genetic strains. A case study was conducted to: a) assess current tilapia feed management practices; b) determine recent nutrition-based innovations that include the use of alternative feed ingredients, the adoption of nutritionally complete commercial tilapia feeds, and improvements to feed management practices; and c) evaluate these factors in terms of improved production efficiencies. Thirty-two farmers from selected tilapia cage hatcheries, pond hatcheries, grow- out cages and ponds in Regions III and IV-A (known major tilapia producing regions in the Philippines) were interviewed. The issues addressed included their farm management practices, with particular focus on tilapia feed preferences; quality, procurement and storage methods; and feeding strategies. Their responses were collated and analysed in the context of information simultaneously gathered from the scientific literature, popular publications and relevant websites. The results from the case study highlight the importance of farmers being trained and remaining well-informed about recent improvements in feed technologies and the use of efficient cost-saving feeding strategies to optimize the production of seed and marketable tilapia. Recommendations on how to increase tilapia production through improved feed and feed management practices are described. Finally, recommendations for local regulatory agencies to implement aquafeed quality and nutrient standards are provided.
    • 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.