Now showing items 1-5 of 5

    • Article

      Effect of storage temperature on the quality of diets for the prawn, Penaeus monodon Fabricius 

      MC de la Cruz, G Erazo & MN Bautista - Aquaculture, 1989 - Elsevier
      The effect of storage temperature was evaluated on the basis of growth response of prawns fed for 10 weeks with diets stored at 0°C, 10°C, 28°C-31°C (ambient temperatures) and 40°C for a period of 10 weeks. Prawns were stocked at 15 pieces per 60-1 oval thank supplied with water at 28°C and 32 ppt in a flow-trough aerated system.There were five replicate tanks per treatment. Lowest weight gain (20 g) was observed for prawns fed the diet stored at 40°C and significantly higher growth response was observed as the storage temperature decreased (30.2g at 28-31°C; 37.7g at 0°C and 10°C). Body size was significantly (P<0.05) affected by diet after 6 weeks of feeding and highly significantly (P<0.01) after 8 weeks of culture.Peroxide values for diets exposed for 10 weeks to 28°-31°C (2.9 meq/kg). The highest survival rate (76%) and feed conversion (8.9%) were observed for prawns fed diets stored at low temperatures (0° or 10°C). Severe necrosis of the hepatopancreatic cells was observed in P. monodon fed with diet stored at the high temperature.
    • Article

      The effects of Vibrio anguillarum extracellular products on Japanese eels 

      MC de la Cruz & K Muroga - Aquaculture, 1989 - Elsevier
      To test the effect of Vibrio anguillarum extracellular products (ECP) on Japanese eels (Anguilla japonica ), test fish were injected intramuscularly with ECP at a dose of 1 mg protein/100 g body weight of fish.At 3,6,12,24 and 36 h post-injection, blood samples were collected for haematocrit, haemoglobin, and serum protein determinations and tissues were fixed in Bouin's solution. Histopathological observations 24 h post-injection revealed that the ECP caused severe damage to muscle tissue, characterized by extensive muscle liquefaction and haemorrhaging. In addition, extensive haemosiderin deposits were observed in the spleen, with lesser deposits occurring in the kidney and liver. Haematocrit, haemoglobin, and serum protein values were lower in ECP-treated fish than in the untreated controls.
    • Article

      Growth and mid-gut cells profile of Penaeus monodon juveniles fed water-soluble-vitamin deficient diets 

      MR Catacutan & M de la Cruz - Aquaculture, 1989 - Elsevier
      Growth and changes in the mid-gut cell morphology of Penaeus monodon juveniles were evaluated after feeding for 35 days with semi-purified diets deficient in water-soluble vitamins. Diets were prepared by deleting one vitamin at a time from the vitamin supplement consisting of cyanocobalamine, folic acid, thiamine, riboflavin, pyridoxine, niacin, choline, inositol and ascorbic acid. Controls were the complete vitamin diet (control diet 1) and the no vitamin diet (control diet 2). Growth rate was poorest for treatment without vitamin supplement and the inositol and choline-deficient diets. Enhanced growth was observed in prawns fed with the riboflavin-deficient diet. All treatments except control diet 1 showed histopathological changes in the mid-gut cells. Detachment or destruction of the epithelial cells were observed in most cases but more severely in treatments without vitamin supplement followed by inositol, choline and vitamin C.
    • Article

      Linoleic (ω6) and linolenic (ω3) acids in the diet of fingerling milkfish (Chanos chanos Forsskal) 

      MB Teruel & MC de la Cruz - Aquaculture, 1988 - Elsevier
      Feeding trials were conducted to determine the effects of linoleic acids on growth, survival, fatty acid composition and liver histology of milkfish. Five isocaloric semi-purified diets were formulated, either lipid-free or containing the following lipids: 7% lauric acid (LA), 6% LA + 1% linoleic, 6% LA + 1% linolenic acid, and 6% LA + 0.5% linoleic + 0.05% linolenic acids, and fed to milkfish with an average weight of 1.55 ± 0.25 g. there were no significant differences in growth or survival between fish fed the lipid-free and the LA diets in the five treatments tested. However, growth of fish fed with linoleic and linolenic acids was significantly higher (P<0.05) than that obtained in fish fed lipid-free and LA diets. The best growth response (233%) was attained with fish fed linolenic acid alone. Fatty acid analyses of the total lipid showed that lipid-free and LA diets increased the levels of monoenoic acids in the fish. The addition of linoleic and linolenic acids, alone or in combination, suppressed the levels of these monoenes and increased the levels of polyunsaturated fatty acids (PUFA). Histological analyses using light microscopy revealed slight abnormalities in the hepatocytes of fish fed lipid-free and LA diets. Both linoleic and linolenic acids are effective for good growth and survival of fingerling milkfish; however, the effect of linolenic acid on the growth of this species is better than that of linoleic acid.
    • Article

      Occurrence of Vibrio sp. infection in grouper, Epinephelus suillus 

      CR Lavilla-Pitogo, AR Castillo & MC de la Cruz - Journal of Applied Ichthyology, 1992 - Blackwell Publishing
      Vibrio sp., was consistently isolated from grouper, Epinephelus suillus, with bacterial infection. Fingerlings, which were challenged with the bacterium by injection, were highly susceptible. Immersion challenge resulted in 100% mortality within 48 hrs in fish subjected to combination of injury and exposure to the bacterium. Mortality in uninjured fish was observed in the long bath subgroup, but not in the short bath subgroup. These results are correlated with the present practices in the grouper fingerling industry in the Philippines.