Growth and production of milkfish (Chanos chanos) in brackishwater ponds: effects of dietary protein and feeding levels
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The most economical combination of dietary protein and feeding levels for milkfish culture in brackishwater ponds was determined. Milkfish juveniles (average weight, 5 g) were stocked at 7000/ha and fed two diets containing 24% or 31% dietary protein at 2% or 4% of body weight.There was no interaction between feeding level and dietary protein on growth, feed efficiency, and energy assimilation of milkfish. This indicates that the response of milkfish to change in protein levels is not influenced by ration size. Regardless of protein levels, the final weight, weight gain, specific growth rate, and production of milkfish were significantly higher (P < 0.05) when fed at 4% body weight than at 2%. As culture progresses, differences in weights of fish fed varying protein levels were still insignificant. This could be attributed to the balanced amino acid profile of both diets. But, fish weights vary significantly among milkfish fed at different levels. The higher growth at 4% feeding level could be due to the higher amount of amino acids supplied to the fish for protein synthesis. These results suggest that growth will depend on the amount of amino acids supplied when the amino acid profile of the diet is balanced. Higher energy assimilated by milkfish at higher feeding rate demonstrated that energy supply also influences growth. Partial budgeting analysis revealed that bigger profits can be earned by using an amino acid balanced diet with 24% protein at a feeding rate of 4% of body weight. The greater amount of feed given at higher feeding rate can be compensated by faster growth and higher production.
PublisherAquaculture Department, Southeast Asian Fisheries Development Center
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Conference paperLV Benitez - 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.
Lactate dehydrogenase isozyme patterns during the development of milkfish, (Chanos chanos (Forskal)) PD Requintina, LM Engle & LV Benitez -
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).
Book | Conference publication
Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia and Prospects for Seafarming and Searanching, 19-23 August 1991, Iloilo City, Philippines F Lacanilao, RM Coloso & GF Quinitio (Eds.) - 1994 - Aquaculture Department, Southeast Asian Fisheries Development CenterDocuments the presentations at ADSEA '91, the 2nd Seminar-Workshop on Aquaculture Development in Southeast Asia. ADSEA '91 includes reviews of the status of the researches conducted by Southeast Asian Fisheries Development Center, Aquaculture Department (SEAFDEC/AQD) on the following cultured species sea bass, groupers, snappers, milkfish, rabbitfish, mullet, tilapia, carp, catfish, bivalves and the seaweed Gracilaria. Topics on aquaculture development in Southeast Asia and Japan were also discussed. The status and development of seafarming and searanching in different SEAFDEC member countries and their ecological, social and economic implications were also presented. The contributions of the selected participants during the meeting which are contained in this volume are cited individually.