Now showing items 1-20 of 26

    • Article

      Arginine and threonine requirements of milkfish (Chanos chanos Forsskal) juveniles 

      IG Borlongan - Aquaculture, 1991 - Elsevier
      Growth studies were conducted with milkfish (Chanos chanos Forsskal) juveniles to determine the quantitative requirements for arginine and threonine. The amino-acid test diets (40% crude protein) contained casein and gelatin supplemented with crystalline L-amino acids to provide an amino-acid profile similar to milkfish protein except for the test amino acid. Each set of experimental diets consisted of six isonitrogenous and isocaloric diets containing graded levels of the essential amino acid to be tested. Break-points in the growth curves which represent the optimum dietary concentration of arginine and threonine for fish growth were determined by the broken-line regression method. Based on dry diet, the requirement of milkfish juveniles for arginine is 2.10% and for threonine, 1.80%. These values correspond to 5.25% arginine and 4.50% threonine when expressed as a percentage of dietary protein.
    • Conference paper

      Changes in lipid and fatty acid content during early larval development of milkfish (Chanos chanos): influence of broodstock diet 

      CL Marte, IG Borlongan & AC Emata - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The influence of amount and type of lipid given to milkfish broodstock by developing larvae was investigated by feeding broodstock commercial diets that differed in lipid content and composition. The two commercial feeds used had the following proximate composition: RFP - 28.16% crude protein, 2.40% crude fat, 7.58% crude fiber, 53.94% N-free extract; RCP - 43.28% crude protein, 4.58% crude fat, 6.18% crude fiber, 37.0% N-free extract.

      The lipid content and fatty acid composition of spawned milkfish eggs reflected that of the broodstock feed. Percent lipid in egg from broodstock fed RFP and RCP dropped by 22.5% and 26.9% in newly-hatched larvae and by 53.0% and 65.0% in day 2 larvae (>90% yolk resorbed), respectively. Decreases in total PUFA and increase in monoenoic fatty acids during yolk resorption indicate that milkfish as in other marine fishes utilize PUFA during early larval development. While differences in rate of utilization of individual n-3 and n-6 FA in two groups of larvae seem to be influenced by levels of the fatty acids in eggs, the influence of other nutrients on fatty acid utilization need to be investigated.
    • Book chapter

      Chapter 2. Detection of pesticide residues in aquaculture products 

      IG Borlongan - In Laboratory manual of standardized methods for the analysis of pesticide and antibiotic residue in aquaculture products, 2004 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Agricultural chemicals such as fertilizers and pesticides have made an important contribution to agriculture. Pesticides protect crops from pests and diseases. They have brought about large yield increases, and have helped ensure that the rise in food production has kept well ahead of the rise in population. However, there is a growing concern about the safe use of these chemicals, and the potential dangers to farmers who use them, the environment, and consumers. There is particular concern about pesticides, since almost all chemicals that can kill pests are also potentially damaging to human health.

      Legislation requires that pesticide use is appropriately controlled and maximum residue levels (MRLs) not be exceeded. The level of pesticide residues in food raw materials is a measurable standard. But while residue analysis is essential for companies wishing to assure themselves that their products have been produced in accordance with best practice and within the law, it can be used to greatest effect when targeted at samples most likely to contain residues.

      Reliable residue analytical methods are necessary to measure the magnitude of residue in a seafood, and to enforce legal residue limits (tolerances). Sample preparation and extraction, clean up of extracts and pesticide detection are the main procedures in pesticide residue analysis. There is an interplay among these factors which should be considered in the choice of a particular method.
    • Article

      Dietary phosphorus requirement of juvenile milkfish, Chanos chanos (Forsskal) 

      IG Borlongan & S Satoh - Aquaculture Research, 2001 - Blackwell Publishing
      Seven isocaloric and isonitrogenous diets with graded levels of monopotassium phosphate to yield total phosphorus levels of 0.28 (no P supplementation), 0.43, 0.58, 0.73, 0.88, 1.03 and 1.18% were prepared and fed to five replicate groups of 10 juvenile milkfish (initial weight = 2.5 g). After 16 weeks of feeding, significant differences in growth (300–570%), survival rates (70–100%), and bone and scale mineralization were found among treatment groups. Weight gains of milkfish increased linearly up to the 0.88% dietary phosphorus concentration and levelled off beyond this dietary level. Bone and scale ash, calcium and phosphorus concentrations showed similar patterns as weight gain in response to dietary phosphorus concentration. Broken-line regression analyses of these data indicated that the dietary phosphorus level required for optimal growth and mineralization of juvenile milkfish is ≈ 0.85% of dry diet.
    • Article

      Dietary requirement of milkfish (Chanos chanos Forsskal) juveniles for total aromatic amino acids 

      IG Borlongan - Aquaculture, 1992 - Elsevier
      The phenylalanine requirement of milkfish at two dietary tyrosine levels was determined using a 2× 6 factorial feeding experiment. The amino acid test diets (45% crude protein) contained vitamin-free casein and gelatin supplemented with crystalline L-amino acids to provide an amino acid profile similar to milkfish tissue protein except for the test amino acid. The experimental diets consisted of 12 isonitrogenous and isocaloric diets containing six graded levels of phenylalanine (1.18, 1.3, 1.6, 1.9, 2.2, and 2.5% of dry diet) at two levels of tyrosine (0.45 and 1.2% of dry diet). Each of the 12 diets was fed to triplicate groups of 15 milkfish juveniles (initial mean weight = 0.58 ± 003 g) for 12 weeks.

      Breakpoint linear regression analysis of the growth data estimated the phenylalanine requirement to be 1.90% of the dry diet (4.22% of dietary protein) at 0.45% dietary tyrosine. In the presence of 1.2% dietary tyrosine, the phenylalanine requirement was estimated to be 1.26% of the dry diet (2.80% of dietary protein), suggesting that tyrosine can supply a portion of the total aromatic amino acid requirement thereby sparing phenylalanine. The optimum total aromatic amino acid requirement of milkfish obtained in the study was 5.22% of dietary protein and the replacement value of tyrosine for phenylalanine was computed to be about 46%. Total aromatic amino acid levels higher than 6.88% caused a significant depression of growth in milkfish juveniles.
    • Article

      Dietary vitamin C and E supplementation and reproduction of milkfish Chanos chanos Forsskal 

      AC Emata, IG Borlongan & JP Damaso - Aquaculture Research, 2000 - Blackwell Science Ltd
      Milkfish Chanos chanos Forsskal broodstock (11 years old, average body weight 5.23–5.73 kg) reared in 10-m-diameter by 3-m-deep floating net cages (31–36 fish per cage) at SEAFDEC AQD's Igang Marine Substation in Guimaras Island, central Philippines, were fed daily at 3% of total body weight formulated diets (36% protein, 7–8% lipid) supplemented with 0.1% vitamin C, 0.05% vitamin E, both vitamin C and E or no vitamin supplementation (control) for 3 years. Reproductive performance was assessed in an attempt to determine the optimum nutrition for successful spawning of milkfish. The total egg production, mean number of eggs per spawning, number of spawns and mean egg diameter were not affected by dietary vitamin C and E supplementation. However, broodstock given dietary supplementation of vitamin C alone or in combination with vitamin E had a higher percentage of spawns with higher (> 90%) percentage egg viability, hatching and cumulative survival rate than those of the control. Broodstock given dietary vitamin E supplementation alone had few spawns, which made the results difficult to analyse. The results confirm the essentiality of vitamin C supplementation in producing more spawns with good egg and larval quality. The production of an adequate volume of good quality eggs and larvae to support hatchery operation is necessary to offset the huge investment in broodstock development, as it takes at least 5 years for milkfish to attain sexual maturation and spawning.
    • Article

      Effect of dietary lipid sources on growth, survival and fatty acid composition of sea bass (Lates calcarifer, Bloch) fry 

      IG Borlongan & MM Parazo - The Israeli Journal of Aquaculture-Bamidgeh, 1991 - Society of Israeli Aquaculture and Marine Biotechnology
      Soybean oil, cod liver oil and coconut oil were tested singly or in combination (1:1) as a source of dietary lipid for sea bass fry. Growth and survival rates of fry fed a diet containing cod liver oil and soybean oil (1:1 ratio) were highest, followed by those fed cod liver oil alone and soybean oil alone. Fry growth and survival rates were low in the coconut oil diet and lowest in the diet containing no lipid supplement. The fatty acid profiles of the sea bass fry were influenced by the fatty acid composition of the dietary lipid sources they were fed. Sea bass fry appear to favor lipid over carbohydrate as a major source of energy and a blend of cod liver oil and soybean oil was an effective dietary lipid source. Thus, a substantial savings in feed costs can be achieved if soybean oil is substituted in part for fish oil as a dietary lipid source for sea bass fry.
    • Article

      The essential fatty acid requirement of milkfish (Chanos chanos Forsskal) 

      IG Borlongan - Fish Physiology and Biochemistry, 1992 - Springer Verlag
      The essential fatty acid (EFA) requirement of milkfish was examined by a 12-week feeding trial using defined, purified diets at water temperature of 28–29°C and salinity of 32‰. The test diets contained varying levels of 18:0 (triglyceride form, TG), 18:3(n−3), 18:2(n−6) and (n−3) highly unsaturated fatty acids (n−3 HUFA). Milkfish juveniles were starved for 7 days and were than fed lipid-free diet for 30 days before the initiation of feeding trials. Low growth and feed efficiency together with high mortalities were observed in fish fed the lipid-free diet as well as in the EFA-deficient diet. Supplementation of 2% 18:2(n−6) to the tristearin based diet did not improve growth rate of milkfish as effectively as feeding with (n−3) fatty acids. The highest weight gain was obtained in milkfish fed a combination of 5% 18:0 + 1.0% 18:3(n−3) + 0.5% 20:5(n−3) + 0.5% 22:6(n−3) although the supplementation of 2% 18:3(n−3) alone or combination of 0.5% 20:5(n−3) + 0.5% 22:6(n−3) to the tristearin based diets were also effective for improvement of growth. Thus, (n−3) fatty acids, such as 18:3(n−3) and (n−3)HUFA were nutritionally more important than 18:2(n−6) for milkfish. The fatty acid composition of the polar lipids from whole body of milkfish juveniles fed the various test diets were influenced by the composition of the dietary fatty acids.
    • Article

      Essentiality of phosphorus, magnesium, iron, zinc, and manganese in milkfish diet 

      MGG Miñoso, IG Borlongan & S Satoh - Fisheries Science, 1999 - Japanese Society of Fisheries Science
      Six semi-purified casein based diets were formulated to contain either a complete mineral mixture (control) or mineral premixes from which a specific test mineral was deleted to obtain phosphorus(P)-free, magnesium(Mg)-free, iron(Fe)-free, zinc(Zn)-free, or manganese(Mn)-free diets. These diets were fed to juvenile milkfish (mean initial weight 2.60±0.08g) for a 22-week experimental period. Final mean percent weight gain ranged from 1022 to 1379% with P-free (1022%) and Fe-free (1066%) diets obtaining a significantly lower weight gain (p<0.01) than the control diet (1270%). Survival was greater than 90% and did not differ significantly among treatments.

      Upon termination of the growth experiment, milkfish flesh, bones, and combined samples of head, skin, and scales were dissected and analyzed for ash, P, Ca, Mg, Fe, Zn, and Mn content. The deletion of P or Fe from mineral mixture lowered P content in flesh and bone. Zn content in bone of fish was also lowered by exclusion of Zn, Mn, Mg or Fe. The result of this study demonstrated that it is necessary to supplement P and Fe even to semi-purified casein based diets.
    • Book chapter

      Feeding habits and digestive physiology of fishes 

      IG Borlongan, RM Coloso & NV Golez - In OM Millamena, RM Coloso & FP Pascual (Eds.), Nutrition in Tropical Aquaculture: Essentials of fish nutrition, feeds, and feeding of tropical aquatic species, 2002 - Aquaculture Department, Southeast Asian Fisheries Development Center
      This chapter provides basic information on the feeding habits and behavior, and physiology of fishes and crustaceans. The mechanisms that control the movement and digestion of food, methods of assessing digestibility of feed, factors affecting digestion and absorption of food nutrients, and feeding processes in fish are discussed. An understanding of the feeding habits, feeding mechanisms, and the digestion and absorption processes can help fish farmers and nutritionists maximize the use of feed. The rate at which fish digest their food is of primary importance in determining feeding rates, frequency, and ration size. Knowledge of the digestive physiology of fish is also necessary for an effective feed formulation and in choosing a proper feeding regime.

      This chapter aims to teach the reader: the feeding habits and behavior of fishes and crustaceans; the structural adaptation in the anatomy of the digestive tract; the various organs of the digestive systems of fishes and crustaceans and their functions; nutrient digestion and absorption by fishes and the fate of digested and undigested food; the factors that affect the rate of digestion and absorption; and the feeding process in fish.
    • Article

      Growth and production of milkfish (Chanos chanos) in brackishwater ponds: effects of dietary protein and feeding levels 

      NS Sumagaysay & IG Borlongan - Aquaculture, 1995 - Elsevier
      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 (α = 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. The higher growth at the 4% feeding level could be due to the higher amount of amino acids available for protein synthesis. Higher energy assimilated by milkfish at higher feeding rate demonstrates that energy supply also influences growth. Partial budgeting analysis shows that bigger profits can be earned by using a 24% protein diet with balanced amino acids at a feeding rate of 4% of body weight. The greater amount of feed given at higher rate can be compensated by faster growth and higher production.
    • Book

      Laboratory manual of standardized methods for the analysis of pesticide and antibiotic residue in aquaculture products 

      IG Borlongan & JNP Chuan - 2004 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The manual contains guidelines on the detection of antibiotic and pesticide residues in aquaculture products. Different methods for the analysis of the two chemicals are discussed. The manual is expected to benefit all those who are involved in the monitoring and enforcement aspects of chemical residue limits in aquaculture products in the region.
    • Article

      Lipid and fatty acid composition of milkfish (Chanos chanos Forsskal) grown in freshwater and seawater 

      IG Borlongan & LV Benitez - Aquaculture, 1992 - Elsevier
      The lipid and fatty acid compositions of the various organs of milkfish fed with an invariant diet and reared in seawater (SW) and freshwater (FW) were determined using column chromatography and gas chromatography. Phospholipid content of the gills, kidney, liver, intestines and depot fat was higher in SW than in FW while the organs from fish in FW had higher contents of neutral lipid. Fatty acid patterns of total lipids in the liver, intestines and depot fat of milkfish reared in FW and SW were similar. There were marked differences in fatty acid patterns of gills and kidney. The proportions of saturated to unsaturated fatty acids in gills and kidney were lower in SW than in FW. Likewise, the ratio of n-3 to n-6 fatty acids and total polyunsaturated fatty acids (PUFAs) of gills and kidney were higher in SW than in FW. The fatty acid patterns of the phospholipid fractions showed that SW-reared milkfish have higher total PUFAs, especially of the n-3 fatty acids, than the FW-reared milkfish not only in gills and kidney but in all organs examined. The differences in lipid and fatty acid composition reflect a physiological response to the salinity in which milkfish were reared.
    • Article

      Lysine and arginine requirements of juvenile Asian sea bass (Lates calcarifer) 

      DP Murillo-Gurrea, RM Coloso, IG Borlongan & AE Serrano Jr. - Journal of Applied Ichthyology, 2001 - Blackwell Publishing
      Two separate experiments were conducted to determine the dietary requirements of juvenile Asian sea bass Lates calcarifer Bloch for lysine and arginine. Fish (average initial weight: lysine experiment, 13.12 ± 0.12 g; arginine experiment, 2.56 ± 0.13 g) were given amino acid test diets for 12 weeks containing fish meal, zein, squid meal, and crystalline amino acids. Each set of isonitrogenous and isocaloric test diets contained graded levels of L-lysine or L-arginine. The feeding rate in the lysine experiment was at 4–2.5% of the body weight day−1, while in the arginine experiment it was at 10–4% of the body weight day−1. The fish (20 per tank, lysine experiment; 15 per tank, arginine experiment) were reared in 500-L fibreglass tanks with continuous flowthrough sea water at 27 °C and salinity of 31 ppt in the lysine experiment and at 29 °C and salinity of 29 ppt in the arginine experiment. The experiments were in a completely randomized design with two replicates per treatment. Survival was high in fish given adequate lysine or arginine. Mean percentage weight gains were significantly different in fish fed varying levels of lysine or arginine. Fish fed high levels of L-arginine suffered high mortalities. No significant differences were obtained in the feed efficiency ratios (FER, g gain g−1 feed) of fish fed graded lysine, although the values tended to increase as the dietary lysine level was increased up to the requirement level. In contrast, in the arginine experiment, significant differences in FER of fish among treatments were obtained; the highest FER was observed in fish fed the diet containing an optimum arginine level. On the basis of the growth response, survival, and FER, the lysine and arginine requirements of juvenile Asian sea bass were estimated to be 20.6 g kg−1 dry diet (4.5% protein) and 18.2 g kg−1 dry diet (3.8% protein), respectively. These data will be useful in the further refinement of practical diet formulations for the Asian sea bass.
    • 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.
    • Article

      Molluscicidal activity of tobacco dust against brackishwater pond snails (Cerithidea cingulata Gmelin) 

      IG Borlongan, RM Coloso, EF Mosura, FD Sagisi & AT Mosura - Crop Protection, 1998 - Elsevier
      Toxicity tests on the effect of tobacco dust against brackishwater pond snails (Cerithidea cingulata Gmelin) of various stages or size ranges were conducted under controlled laboratory conditions. The 72-h LC50 for the juveniles, sub-adult and adult snails are 30, 87 and 166 kg ha−1, respectively, while the 72-h LC99 are 290, 522 and 712 kg ha−1, respectively. The nicotine content of the tobacco dust used was 2.8%. Lethal concentration increased as the life stages or size of the snail increased. Molluscicidal activity also progressively increased with time of exposure. The nicotine content and toxicity of different types of tobacco [flue-cured (neutral), flue-cured (full-flavor), burley and batek (full-flavor)] were determined on adult snails. Lethal concentrations (LC50) and (LC99) decreased as nicotine content of the tobacco dust increased indicating a higher molluscicidal activity. The effective application rate is affected by the nicotine content of the tobacco dust. An equivalent nicotine concentration of ca 24 kg ha−1 corresponded with the 72-h LC99 under laboratory conditions. Sevenday bioassay experiments on the effect of tobacco dust on two size groups of milkfish juveniles (0.5 and 2–3 g) showed no mortalities up to the concentration lethal to the pond snails.
    • Article

      Potential of feed pea (Pisum sativum) meal as a protein source in practical diets for milkfish (Chanos chanos Forsskal) 

      IG Borlongan, PS Eusebio & T Welsh - Aquaculture, 2003 - Elsevier
      A 12-week feeding trial was conducted to evaluate the use of feed pea meal as a dietary protein source for juvenile milkfish. Six isonitrogenous (30% crude protein) and isocaloric (16.5 kJ/g) practical diets were formulated. The control diet contained fish meal, soybean meal, meat and bone meal and copra meal as principal protein sources. Feed pea meal was progressively substituted at 0%, 5%, 10%, 15%, 20%, 25% and 30% of total protein. A leading commercial milkfish feed was also tested as an additional control. The experimental diets were fed to triplicate groups of milkfish fingerlings (mean initial weight of 0.42±0.01 g) at 10% body weight/day. Growth performance (expressed as percentage of weight gain and SGR), survival, feed conversion ratio (FCR) and protein efficiency ratio (PER) of milkfish fed diets with up to 10% substitution of the dietary protein with feed pea meal were not significantly different (P>0.05) compared to fish fed the control diet. Replacement with feed pea meal at 15% and higher levels led to milkfish fed these diets showing a significantly lower growth response compared to fish fed with the control without any feed pea meal. Nevertheless, it was observed that milkfish fed diets with up to 20% of total dietary protein substitution with feed pea meal showed better growth rates and feed conversion ratios than the commercial feed control. Whole body composition (crude protein, crude fat, crude fiber, nitrogen-free extracts and ash content) of milkfish fed the various test diets was not significantly different. Apparent digestibility coefficients of feed pea meal and experimental diets in milkfish were also determined. Results indicate that feed pea meal is an acceptable protein source and can replace up to 20% of the total dietary protein in milkfish diets.
    • Article

      A practical broodstock diet for the mangrove red snapper, Lutjanus argentimaculatus 

      AC Emata & IG Borlongan - Aquaculture, 2003 - Elsevier
      A practical broodstock diet (39% protein, 8.6% lipid) was formulated for the mangrove red snapper as part of a project to ensure consistent production of good quality eggs and larvae through broodstock nutrition. Reproductive performance of mangrove red snapper broodstock fed practical diet (n=14 females) was enhanced in comparison to those fed raw fish (n=12 females). Broodstock fed practical diet had total egg production of 82.34 million from 68 spawns for two spawning seasons while broodstock fed raw fish produced 77.64 million eggs from 66 spawns. Mean percent of egg viability, hatching rates and percent of normal larvae did not vary between the two groups. However, broodstock fed the practical diet had higher mean cumulative survival rate of eggs to normal larvae (40.4%) than that of broodstock fed raw fish (35.2%). Also, survival activity index (4.08) of broodstock fed practical diet was higher than that of broodstock fed raw fish (2.97). The results clearly indicate the improvement of reproductive performance of mangrove red snapper fed practical diet. Further studies should focus on the specific nutrients that can ensure consistent production of high quality eggs and larvae of the mangrove red snapper to support its aquaculture.
    • Article

      Quantitative lysine requirement of milkfish (Chanos chanos) juveniles 

      IG Borlongan & LV Benitez - Aquaculture, 1990 - Elsevier
      A feeding experiment was conducted to determine the quantitative dietary requirement of milkfish juveniles for lysine. Milkfish (Chanoschanos Forsskal) of mean weight 5.92±0.14 g were fed diets containing 7.0, 11.0, 15.0, 19.0, 23.0 and 27.0 g lysine/kg dry diet for 12 weeks. The amino acid test diets contained white fish meal and zein supplemented with crystalline amino acids to provide an amino acid profile similar to milkfish proteins except for lysine. Each of the six diets was fed to four replicate groups of 25 fish in a completely randomized design and at a feeding rate of 5% of the fish body weight per day. On the basis of the growth response, lysinerequirement of juvenile milkfish was found to be 20 g/kg diet. This value corresponds to 4.0% when expressed as a percentage of the dietary protein. Survival (94–97%) was consistently high in all treatments. Except for loss of appetite resulting in low food intake and depressed growth, no nutritional deficiency signs were observed in fish given the lysine-deficient diets.
    • Article

      Requirements of juvenile milkfish (Chanos chanos Forsskal) for essential amino acids 

      IG Borlongan & RM Coloso - Journal of Nutrition, 1993 - American Society for Nutrition
      The dietary requirements of juvenile milkfish (Chanos chanos Forsskal) for essential amino acids were determined in a series of experiments. The fish (< or = 8.0 g) were reared in fiber glass tanks provided with flow-through seawater at 28 degrees C and salinity of 32 g/L for 12 wk. In each experiment, a series of amino acid test diets was formulated containing a combination of intact protein sources (casein-gelatin, fish meal-gelatin, fish meal-soybean meal or fish meal-zein) and crystalline amino acids to simulate the levels found in milkfish tissue proteins except for the test amino acid. Each set of isonitrogenous diets contained 40-45% protein and graded levels of the amino acid to be tested. At the end of the feeding experiment, growth, survival and feed efficiency were determined. The requirement level for each essential amino acid was estimated from breakpoint analysis of the growth curve. The dietary essential amino acid requirements (as the percentage of dietary protein) of milkfish juveniles were as follows: arginine, 5.25; histidine, 2.00; isoleucine, 4.00; leucine, 5.11; lysine, 4.00; methionine, 2.50 (cystine, 0.75); phenylalanine, 4.22 (tyrosine, 1.00) or 2.80 (tyrosine, 2.67); threonine, 4.50; tryptophan, 0.60; valine, 3.55. This information is valuable in developing cost-effective practical or commercial feeds and research diets for milkfish juveniles.