Studies on the digestive lipases of milkfish, Chanos chanos
Abstract
Milkfish grown on two natural foods were examined to determine the distribution pattern of the digestive lipases along the digestive tract and to identify the optimum condition for lipase activity. One food consisted of a biological complex of unicellular algae and diatoms (Food A) and the other consisted of fibrous filamentous green algae, predominantly Chaetomorpha brachygona (Food B). The major sites of lipase secretion in milkfish digestive tract were the intestines, pancreas and pyloric caeca. Lipase activity was somewhat higher for fish grown on Food A than those grown on Food B. Intestinal lipase activity was observed to be maximal at 45°C and at pH 6.8 and 8.0. Activity of pancreatic lipase was observed to be maximal at 50°C and at pH 6.4 and 8.6. The detection of two well-defined pH optima, one at slightly acidic and the other at alkaline pH for both the intestinal and pancreatic lipases suggests a physiological versatility for lipid digestion in milkfish.
Citation
Borlongan, I. G. (1990). Studies on the digestive lipases of milkfish, Chanos chanos.Publisher
ElsevierSubject
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- Journal Articles [1046]
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Conference paper
Milkfish nutrition: a review
- In RD Fortes, LC Darvin & DL de Guzman (Eds.), Fish and crustacean feeds and nutrition : Proceedings of the seminar-workshop on fish and crustacean feeds and nutrition held on 25-26 February 1985 at UPV, Iloilo City, 1989 - Philippine Council for Aquatic and Marine Research and DevelopmentThis paper reviews recent work on milkfish nutrition. Substantial progress had been made towards understanding the digestive physiology of milkfish. Major enzaymes envolved in the digestions of carbohydrates, protein and lipids had been detected in the pyloric caece, intestines and pancreas of milkfish. The most active carbohydrates were involved in the hydrolysis of α - glocosidic bonds. Intestinal amylase activity consistently reached the peak at about noon when milkfish gut was full. This confirms that milkfish is s daytime feeder. No cellulase activity was detected in any region orf the digertive treat although the fish relies heavily algae and other plant source for food. Trypsin, chymotrypsin and general proteases were also detected in milkfish digestive tract. A powerful milkfish trypsin inhabitor was detected in the filementous algae, Chaetomorpha brachygona which is predominant species in lumot. Lipass in the pancreas and intestines had two pH optima, suggesting a physiologic versatility for lipid digestion in milkfish. There is a limit information on the nutrient requirement of milkfish. Most studies showed that milkfish fry has a dietary requirement of 40% protein, and 7-10 lipid. Studies on the protein-energy requirement of fingerlings suggested that 30-40% protein, 10% fat and 25% carbohydrates are required. Subsequent studies showed an optimum protein energy to total metabolizable energy ratio of 44.4%. Amino acid test diets for milkfish had been formulated to contain white fish meal, gelatin and approprate amino acid mix. -
Article
Lactate dehydrogenase isozyme patterns during the development of milkfish, (Chanos chanos (Forskal))
-Kalikasan, The Philippine Journal of Biology , 1981 - University of the Philippines at Los BañosPolyacrylamide disc gel electrophoresis was done to determine the lactate dehydrogenase (LDH) isozyme patterns for fry (5-3 mg), fingerling (6-12 g), pond-size (150-250 g) and adult (6-9 kg) milkfish. The patterns were tissue specific; the different tissues examined, viz., eye, liver, heart, and skeletal muscle had different expressions of LDH isozymes. The resolved patterns appeared to be products of LDH gene loci A, B, and C. Subunits A and B were present in all tissues. A4 and B4 were predominant in skeletal and heart muscle, respectively; the two associated non-randomly in vivo and formed only the heteropolymers A3B and AB3. A liver band, L4, was most conspicuous in the fingerling, pond-size, and adult; it was assumed to be coded by locus C. A negatively charged band, X4, was detected in fully developed ovary and in fry homogenized as whole individuals, but it could not be resolved in tissues of fingerling. Six-mo old stunts and 3-mo old fingerlings had similar LDH patterns for all tissues examined. The patterns for 11-mo old stunts and fingerlings also were similar but the one for the eye of the former was the same pattern resolved for the eye of adults. There was no change in the LDH isozyme patterns of milk fish stunted for 6 mo under different salinity levels (0-5, 15-20, 32-35 ppt). -
Conference paper
Larviculture of marine fishes at SEAFDEC/AQD
- In CT Villegas, MT Castaños & RB Lacierda (Eds.), Proceedings of the Aquaculture Workshop for SEAFDEC/AQD Training Alumni, 8-11 September 1992, Iloilo, Philippines, 1993 - Aquaculture Department, Southeast Asian Fisheries Development CenterThe recent glut in the world market for shrimp dealt a heavy blow to the aquaculture industry. It is thus apparent that fish farmers should not depend on only a single species for culture. The popularity and market demand for grouper, sea bass, and snapper make them obvious choices as alternative culture species. On the other hand, milkfish and rabbitfish are cheaper sources of protein and they already contribute substantially to fish production from aquaculture--56.2% from milkfish for example (Rabanal 1988). However, culture and production of marine fishes are hindered by the unpredictable and seasonal seed supply. Research on larviculture at SEAFDEC/AQD are geared towards hatchery production of fry to augment supply from the wild.
