Now showing items 1-2 of 2

    • Article

      Development of larval diets for milkfish (Chanos chanos) 

      IG Borlongan, CL Marte & JN Nocillado - Journal of Applied Ichthyology, 2000 - Blackwell Publishing
      This study aimed to develop nutritionally balanced and costeffective processed diets for milkfish larvae (Chanos chanos). Two larval diets (feed A and feed B) were formulated and prepared to contain 45% protein and 10% lipid. Several larval diet preparations were tried such as microbound/unpelleted (freeze-dried), microbound /pelleted (oven-dried) and microbound/flaked (drum-dried) and assessed in terms of feed particle size and buoyancy, water stability and feed acceptability. The preparation that gave the best particle size and buoyancy as well as good water stability was prepared as the microbound diet (using K-carrageenan as a binder) and flaked using a drum drier. A series of feeding experiments were conducted to determine the growth and survival of milkfish larvae reared on various feeding schemes using these processed larval diets which were fed either solely or in combination with live feed. Larvae in control treatments were reared on live foods such as Brachionus plicatilis and Artemia nauplii. Larvae were observed to ingest the diets, indicating that the feeds had suitable physical characteristics and were attractive to the larvae. The overall results of the feeding trials showed that the artificial diets could be fed to milkfish larvae in combination with Brachionus rotifers starting on day 2 or day 8, and could be fed alone starting from day 15. These promising results would reduce the dependence of milkfish larvae on live feed and would have significant economic benefits in the form of simplified milkfish hatchery procedures.
    • Article

      Measures of egg quality in induced spawns of the Asian sea bass, Lates calcarifer Bloch 

      JN Nocillado, VD Peñaflorida & IG Borlongan - Fish Physiology and Biochemistry, 2000 - Springer Verlag
      The egg morphometry and lipid and protein components were determined in induced spawns (n = 14) of the sea bass, Lates calcarifer, to identify measures of egg quality. Based on fertilization and hatching rates, the spawns were classified either in Group I, (zero fertilization) or Group II (where fertilization and hatching occurred). The egg morphometry did not differ between the two groups (p > 0.05). The total lipid was higher in Group II than in Group I, although the difference was not significant (p > 0.05). The EPA and linoleic acid were significantly higher in Group II (p < 0.05). There were positive correlations between the total saturated fatty acids and fertilization rate (p < 0.05; r = 0.58), the total saturated fatty acids and percentage of normal zygotes (p < 0.02; r = 0.62), and DHA and the percentage of normal zygotes (p < 0.04; r = 0.56). The total protein and FAAs were higher in Group I than in Group II, but the differences were not significant (p > 0.05). Proline, glycine, p-ethanolamine, and aspartic acid were significantly higher in Group II (p < 0.05), while tyrosine and glutamic acid were significantly higher in Group I (p < 0.05). Phosphoserine and fertilization rate were positively correlated (p < 0.03; r = 0.60), as well as aspartic acid and hatching rate (p < 0.05; r = 0.54). Arginine was negatively correlated with fertilization rate (p < 0.03; r = -0.61) and the percentage of normal zygotes (p < 0.03; r = -0.63). Serine was inversely correlated with yolk volume of the newly-hatched larvae (p < 0.03; r = -0.77). The moisture content of the eggs, which was significantly higher in Group II than in Group I (p < 0.03), was directly correlated with the FAAs:protein ratio (p < 0.03; r = 0.76). The present results reveal egg components that may be used as quality measures in induced spawns of sea bass, a euryhaline teleost that spawn pelagic eggs containing an oil globule.