Amino acid analysis of P. monodon muscle

Figures for the amino acid composition of Penaeus monodon, are tabulated, and compared to those for white tuna meat

Growth and survival of juvenile tiger shrimp fed diet where fish meal is partially replaced with papaya (Carica papaya L.) or camote (Ipomea batatas Lam.) leaf meal

Fish meal is the major protein source in shrimp and fish diets but its continuous use would make it scarce and expensive. There are, however, potential substitutes like soybean or leaf meals. Papaya or camote leaf meals have not been tested as partial replacement for fish meal in diets for tiger shrimp. Thus, two feeding trials were made to test diets with leaf meals against a control shrimp diet. Both experiments used 50 mg shrimp stocked at 10 per 40 liters of sea water following standard water management. Trial 1 had diets containing either 17% soaked or unsoaked camote leaf meal or 16% papaya leaf meal. Results indicated that weight gain, specific growth rate and feed conversion ratio of the unsoaked papaya were similar to the control, higher than the unsoaked camote, but not significantly different (α= 0.05) from the soaked camote and papaya groups. Survival was not significantly different among treatments. Trial 2 used the best diet from Trial 1 - unsoaked papaya leaf meal - at 16%, 19% or 22% of the diet. The weight gain (1846%) of the shrimp fed 16% papaya leaf meal was not significantly different (α= 0.05) from the control 2034% but higher than the 22% group (1535%). Therefore, papaya leaf meal can partially replace (10%) animal protein in shrimp diets and serve as a source of exogenous proteolytic enzyme. However, its efficacy in culturing shrimp in ponds must be tested

Amino acid profiles in the midgut, ovary, developing eggs and zoea of the mud crab, Scylla serrata

Culture of the mud crab, Scylla serrata, is beset by low and inconsistent survival of larvae in spite of the high fecundity of crab breeders. The nutrition of the embryo and pre-feeding zoea depends on what is stored in the egg. The protein and free amino acid contents of the midgut gland, ovary, eggs, pre-feeding zoea, live food and a maintenance diet for broodstock were analyzed by HPLC. The maintenance diet had lower arginine, histidine, methionine, threonine and tryptophan than the ovary and egg. The midgut had higher phenylalanine and valine and lower leucine, methionine and tryptophan than the ovary. Amino acid profiles in the ovary, egg and zoea showed that methionine was highest in the ovary and leucine was highest in the zoea. Low val- ues were observed for isoleucine and valine in ovary, arginine in egg, methionine and pheny- lalanine in zoea. When live foods were compared to zoea, histidine in Brachionus, leucine and tryptophan in Artemia, and arginine, leucine and valine in Acartia were low. Essential free amino acids in fertilized eggs were 2.5 times higher than in unfertilized eggs. Arginine, histidine, lysine, methionine, tyrosine and threonine decreased with egg embryogenesis, suggesting that these are the major free amino acids utilized as the egg develops. Information on egg and zoea amino acids can be used to predict viable crab eggs while information on amino acid profiles in the ovary, egg and zoea can be used to develop broodstock diets. Identification of limiting amino acids in live foods can be used to develop larvae diets

Growth, survival and feed conversion of juvenile shrimp (Penaeus monodon) fed a betaine/amino acid additive

Diets low in animal but high in plant protein were enhanced with a chemoattractant FinnStim (FS), a betaine/amino additive. These were fed to juvenile shrimp, Penaeus monodon, in three tank experiments. All diets were formulated to be isonitrogenous (35% protein) and isocaloric. In run 1, where soybean meal was used as the plant protein source (33%), graded levels of FS (0 to 2.0%) were added to the basic mix (B). Shrimp fed the diet with 1% FS had a significantly ( alpha =0.05) higher weight gain than the other treatments and a feed conversion ratio (FCR) which was higher than B and B+2% FS but not significantly different from the other FS levels. However, survival, specific growth rate (SGR) and feed intake were similar. In run 2 diet palatability, which may be affected by plant protein, was considered. Diets with a lower soybean meal content (18%) and 16% papaya leaf meal, with and without 1% FS, were tested. A higher weight gain and SGR were obtained for shrimp fed FS but survival, feed intake and FCR were not significantly different from those without FS. In run 3, where leaf meal was increased to 25%, shrimp fed 1% FS yielded a significantly better weight gain, SGR, feed intake and FCR, but survival rates were not significantly different. FS did not increase feed intake but may have caused faster feed consumption, resulting in less feed disintegration and nutrient loss. It could also have acted as a stimulant and counteracted the palatability problem of the 25% leaf meal diet. However, much of the response was evidently caused by the physiological role of betaine as methyl donor and osmoprotectant

Variation in the biochemical composition of Penaeus monodon tissues during the reproductive cycle.

The gonadosomatic index (GSI) and the hepatosomatic index (HSI) were determined for wild-caught, eyestalk ablated Penaeus monodon at 5 reproductive stages (I to V). Tissues of the muscle, ovary and hepatopancreas in each stage were analyzed for crude protein and amino acid composition. Results showed that the GSI increased from stage I (immature) to IV (fully mature) but declined at stage V (spent) while the HSI did not change significantly (P less than or equal to 0.05). Muscle protein content did not vary markedly from stage I to V except for a slight lowering at stage III (late maturing). Ovarian protein increased from stage I to IV and decreased at stage V while from stage II, the reverse was true for hepatopancreas. Generally, few significant differences in amino acid content were found. Glutamic acid content significantly differed among stages in all three tissues. In addition, phenylalanine in the muscle, histidine and lysine in the ovary and arginine and luecine in the hepatopancreas differed among stages. The muscle had slightly higher arginine and gluatmic acid contents than the ovary and hepatopancreas but was lower in threonine and valine. The ovary had the lowest glycine content. Results showed similar amino acid levels among tissues and maturation stages, suggesting that amino acids are fixed and not affected by much variation

A practical method of extracting mimosine from ipil-ipil, Leucaena leucocephala, leaves and its effect on survival and growth of Penaeus monodon juveniles

Soaking fresh ipil-ipil, Leucaena leucocephala, leaves in tap water (1:1, v/v; or 50 g in 500 ml) for 30-48 hours with a water change after 24 hours extract atleast 90% of its mimosine, a toxic lysine derivative. This extraction procedure is more economical and practical for fish farmers than the use of dry or moist heat or iron compounds. Soaked or unsoaked leaves of Peruvian or Hawaiian ipil-ipil Leucaena leucocephala formed 1/3 of trial diets fed to Penaeus monodon juveniles (1-2 g). Other protein sources consisted of fish and shrimp-head meals. A diet without ipil-ipil leaves (FS) served as the control. After 8 weeks, the mass weight of shrimp fed the FS and soaked Hawaiian leaf diets (HLS) was significantly (α= 0.05) higher than soaked (PLS) and unsoaked (PLU) Peruvian leaves. The HLS group had a significantly higher survival rate than the PLS and PLU groups but not the FS-fed shrimps; survival among shrimp fed unsoaked Hawaiian leaves (HLU) was zero. It was found that the Hawaiian variety of ipil-ipil leaves when soaked for 24 hours can be incorporated in the P. monodon juvenile diet with good survival (87%) under laboratory conditions. However, the optimum amount of leaves to be included in a low cost and efficient diet has yet to be determined