Now showing items 1-4 of 4

    • Conference paper

      Dietary manipulation to control the chronic soft-shell syndrome in tiger prawn, Penaeus monodon Fabricius. 

      Bautista M.N. & MCL Baticados - In R Hirano & I Hanyu (Eds.), The Second Asian Fisheries Forum. Proceedings of the Second Asian Fisheries Forum, 17-22 April 1989, Tokyo, Japan, 1990 - Asian Fisheries Society
      Penaeus monodon collected from brackishwater ponds in Iloilo, Philippines, were induced to become soft-shelled in the laboratory for 3-4 weeks. Eight isocaloric and isonitrogenous diets containing 0:0; 0:1; 1:0; 1:0.2; 1:1; 1:2; 0.2:1; and 2:1 ratios of Ca to P were fed to the soft-shelled prawn. Shell quality, survival and growth of prawn were observed biweekly. Prawn fed a diet with 1:1 Ca to P ratio (Diet 5) gave the best response in terms of weight gain (62%) and recovery from soft-shelling (89%). Soft-shelled prawn fed Ca-P-deficient diet did not improve in shell quality. Survival ranged from 50 to 100%, ans was significantly low with prawn fed the Ca- or P- deficient diets. The highest levels of both Ca and P occurred in the exoskeleton of normal prawn. The increased levels of these minerals in the exoskeleton in soft-shelled prawn indicated impaired mobilization of these mineral elements from the former to the latter for use in formation and hardening of shell.
    • Article

      Histopathology of the chronic soft-shell syndrome in the tiger prawn Penaeus monodon 

      MCL Baticados, RM Coloso & RC Duremdez - Diseases of Aquatic Organisms, 1987 - Inter Research
      One of the disease problems that affect the production of tiger prawn Penaeus monodon Fabricius in brackish-water ponds is the chronic soft-shell syndrome, a condition in which the prawn shell is persistently soft for several weeks. To determine the extent of damage in affected prawns, the histopathology of this syndrome was studied using light microscopy, transmission and scanning electron microscopy, and histochemical determination of calcium. Light microscopic studies of the exoskeleton of soft and normal hard-shelled prawns showed several distinct layers: an outer epicuticle, a thick exocuticle and a thinner endocuticle overlying the epidermis. The cuticular laters of the soft shell oftern had a rough or wrinkled surface and were usually disrupted and separated from the epidermis while those of the hard shell were generally intact and attached to the epidermis. The exocuticle and endocuticle of the hard shell were considerably thicker than those of the soft shell. Ultrastructural observations revealed the presence of a very thin membranous later under the endocuticle. Tegumental ducts and pore canals traversed the 4 cuticular layers and were distinctly observed as pore openings on the epicuticle surface. The epicuticle had a bilaminar and non-lamellate structure. The exocuticle had more widely-spaced lamellae consisting of fibers arranged in a more compact pattern than in the endocuticle. Histochemical determination of calcium was done in exoskeleton and hepatopancreas of soft- and hard-shelled prawns. The hepatopancreas of soft-shelled prawn stained more intensely for calcium than that of the hard-shelled one. There was no great difference in calcium content of hard and soft shell, although the former stained slightly more intensely. Histopathological changes in the hepatopancreas of soft-shelled prawns were also observed.
    • Article

      In vitro effects of fungicides on the fungus Haliphthoros philippinensis 

      GD Lio-Po, MCL Baticados, CR Lavilla & MEG Sanvictores - SEAFDEC Aquaculture Department Quarterly Research Report, 1981 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Pure cultures of Haliphthoros philippinensis, isolated from infected Penaeus monodon larvae, were exposed for 24 hours to varying concentrations of antifungal agents. The efficiency of each agent to inhibit sporulation and mycelial growth was measured. Effects on P. monodon eggs and larvae were also investigated. It is concluded that preliminary bioassay of larval tolerance to the suggested effective doses should always be made prior to prophylaxix or therapeutic applications.
    • Book

      Recommended practices for disease prevention in prawn and shrimp hatcheries 

      GD Lio-Po, RD Fernandez, ER Cruz, MCL Baticados & AT Llobrera - 1989 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Series: Aquaculture extension pamphlet / SEAFDEC Aquaculture Department; No. 3
      Disease in prawn is any abnormal condition which may affect adversely the appearance, growth, and function of the animal. It may or may not result in mortalities. Disease outbreaks occur commonly in different culture systems such as hatcheries and grow-out ponds.

      Disease develops through the interaction of the prawn (the host), the causal agent (the pathogen), and the environment. In the presence of a susceptible host, a pathogen and predisposing environmental conditions (poor water quality, inadequate food, frequent handling, overstocking), disease is very likely to occur. Improved environmental conditions, healthy prawns and absence of disease agents would therefore lessen the chance of a disease outbreak.

      The causal agents may be pathogenic organisms (viruses, bacteria, fungi, protozoa, helminths, microcrustaceans) or nonpathogenic adverse environmental conditions (extreme temperatures, low oxygen levels, chemical poisons). Living disease agents cause infectious disease which generally result in gradual mortalities. Non-living disease agents cause non-infectious diseases that result in sudden mass mortalities.

      The environment determines the balance between the prawn as host and the disease agent. Microorganisms are always present in the water and some of them cause disease only when the prawn has been weakened through exposure to stressful environmental conditions.

      Hatchery personnel should realize that they themselves could transmit disease through their contaminated hands, clothing, and footwear. Equipment such as water pumps, blowers, pipes, and materials such as scoop nets, water hoses, pails, glasswares are also possible carriers of disease agents. Spawners, live natural food like diatoms, rotifers and brine shrimp, and artificial diets could also be vehicles of disease transmission.

      The prawn culturist, thus, must be able to manage the environment and make it favorable for the prawn. Hatchery management should, therefore, include operation procedures that will reduce the possibility of disease development during larval rearing. This manual recommends practices for disease prevention to prawn hatchery operators and technicians.