Myrna N. Bautista

The response of Penaeus monodon juveniles to varying protein/energy ratios in test diets

Abstract Two sets of factorial experiments were conducted for 8 weeks to determine the response of Penaeus monodon juveniles (average weights = 0.60 ± 0.16 g and 0.80 ± 0.05 g) to diets containing various protein/energy ratios. The first experiment used casein as the sole source of protein, while the other used a combination of 70%:30% casein:gelatin for its protein source. A two-fold increase in the body weight was achieved for prawns fed diet combinations of 40–50% protein, 5–10% lipid and 20% carbohydrate with energy values of 285–370 kcal/100 g, regardless of the protein source used. Reduction in protein content of the diet from 50% to 40% while maintaining the total energy level at 330 kcal/100 g resulted in a non-significant decrease in growth. The inclusion of 15% lipid in the diet produced adverse effects on the animal while sucrose levels beyond 20% resulted in a decreased growth rate. An increase in energy level, at constant dietary protein level, resulted in improved utilization of protein and feed conversion efficiency. Survival of the prawn was higher with diets containing casein and gelatin as the protein source than with those containing casein as the sole source of protein.

Threonine requirement of juvenile marine shrimp Penaeus monodon

The threonine requirement was determined for juvenile marine shrimp. Penaeus monodon postlarvae, PL20, were stocked in 30-1 fiberglass tanks at ten shrimp per tank arranged in a completely randomized design with six replicates per treatment. They were fed amino acid test diets (40% protein) with casein-gelatin as natural protein sources and supplemented with crystalline L-amino acids to simulate the amino acid profile of shrimp muscle except for threonine. Graded levels of threonine were incorporated to obtain 0.72, 1.0, 1.28, 1.56, 1.84, and 2.12 g per 100 g diet or 1.8, 2.5, 3.2, 3.9, 4.6, and 5.3% of dietary protein. Relationship of weight gain with dietary threonine level was analyzed by the quadratic regression method to derive the threonine requirement. Results showed that the quantitative threonine requirement for growth is 1.4% of the diet or 3.5% of dietary protein. This requirement for growth conforms with the threonine level in the shrimp muscle.

Linoleic (ω6) and linolenic (ω3) acids in the diet of fingerling milkfish (Chanos chanos Forsskal)

Abstract Feeding trials were conducted to determine the effects of linoleic and linolenic acids on growth, survival, fatty acid composition and liver histology of milkfish. Five isocaloric semi-purified diets were formulated, either lipid-free or containing the following lipids: 7% lauric acid (LA), 6% LA + 1% linoleic acid, 6% LA + 1% linolenic acid, and 6% LA + 0.5% linoleic + 0.5% linolenic acids, and fed to milkfish with an average weight of 1.55 ± 0.25 g. There were no significant differences in growth or survival between fish fed the lipid-free and the LA diets in the five treatments tested. However, growth of fish fed with linoleic and linolenic acids was significantly higher ( P

Use of kappa-carrageenan microbound diet (C-MBD) as feed for Penaeus monodon larvae

The performance of an artificial practical diet, kappacarrageenan microbound diet (C-MBD) was assessed on Penaeus monodon larvae at the SEAFDEC Broodstock and Maturation Experimental Laboratory in March 1986. Shrimps were reared from zoea1 to post-larvae1 using five dietary treatments: (a) natural food — Chaetoceros calicitrans and Artemia salina (b) C-MBD; (c) combination of natural food and C-MBD; (d) commercial diet (microencapsulated, MED); (e) combination of natural food and commercial diet. Results showed slow development with larvae fed the commercial diet. Feeding with C-MBD in combination with natural food resulted in the highest % survival among treatments (69.6), but this was not significantly different (P>0.05) from those obtained with larvae fed natural food alone, C-MBD alone or their combination. While mean values for survival of larvae fed the commercial diet, either alone or in combination, was significantly lower (p<0.05) than all other treatments, their mean growth indices were comparable with larvae fed C-MBD alone or in combination. The low levels of protein, lipid and essentially fatty acids (which are considered important nutrients during larval development) contained in the commercial diet may well justify the results on metamorphosis, survival and growth of the larvae fed this diet. The good performance of C-MBD in this experiment suggests that this kind of diet can be used as partial or total replacement to the traditional algal food.

Changes in shrimp feed quality and effects on growth and survival of Penaeus monodon juveniles

Abstract Five practical shrimp diets were formulated to contain 1, 10, 20, 50, and 100 g tetraethoxypropane (TEP) kg −1 diet. A diet with no added TEP served as the control. Diets were fed to Penaeus monodon (average weight 4.84 ± 0.11 g) juveniles to determine the level of fat oxidation tolerable to shrimp. Changes in shrimp feed quality were monitored by physical evaluation, thiobarbituric acid (TBA) values, fatty acid composition, and histological examination. Effects of feed quality on growth and survival of shrimp were evaluated. Results showed significant differences ( P −1 diet, showed signs of physical deterioration after 6–8 weeks. This diet had a significantly higher TBA value (1262 mg malonaldehyde kg −1 fat) than the other treatments. The unsaturated fatty acid content of the diet decreased as its TEP content increased. Weight gains of shrimp fed diet 5 (50 g TEP kg −1 diet) and diet 6 were significantly lower than those fed the other diets while survival was similar. Hepatopancreatic lesions were not evident in all samples. Fat oxidation levels expressed in terms of TBA values of up to 828 mg mal kg −1 fat can be tolerated by Penaeus monodon juveniles in terms of growth response.

Lipid and fatty acid composition of brackishwater- and freshwater-reared milkfish (Chanos chanos Forskal)

Abstract Lipid and fatty acid composition of the various sections of brackishwater- and freshwater-reared milkfish were determined by chromatographic methods. Lipids consisted mainly of the neutral type, which in turn was composed primarily of triglycerides and cholesterol esters. Palmitic and stearic acids were the predominant saturated fatty acids in both types of fish, although the brackishwaterreared milkfish contained more palmitic acid and the freshwater-reared milkfish more stearic acid. Unsaturated fatty acids of C16 and C18 were more characteristic of the freshwater-reared milkfish lipid, while those of C20 and C22 were the major acids of the brackishwater-reared milkfish lipid. Saturation and unsaturation in the fatty acid composition characterized both types of fish although the brackishwater-reared milkfish lipids had fatty acids of higher unsaturations (C20 and C22).

Yield of Penaeus monodon Fabricius in brackishwater ponds given different fertilizer combinations

Abstract Yields of Penaeus monodon Fabricius in brackishwater earthen ponds were determined using different fertilizer combinations in two sets of experiments. Results indicated that the use of fertilizers was vitally needed to sustain growth of shrimps at a stocking density of 5000 individuals/ha. Application of urea (45-0-0) and diammonium phosphate (18-46-0) fertilizers at nitrogen to phosphorus fertilizer rates (N:P 2 O 5 ) of 15:15 and 30:15 kg/ha, together with 1 t/ha of chicken manure, was inexpensive and resulted in better yields. In another experiment, increase in the amount of nitrogen and phosphorus fertilizers did not significantly improve prawn yields, but did increase the cost of production. Different salinity levels affected survival in both experiments.

Effect of storage temperature on the quality of diets for the prawn, Penaeus monodon Fabricius

Abstract The effect of storage temperature was evaluated on the basis of growth response of prawns fed for 10 weeks with diets stored at 0°C, 10°C, 28°–31°C (ambient temperatures) and 40°C for a period of 10 weeks. Prawns were stocked at 15 pieces per 60-l oval tank supplied with water at 28°C and 32 ppt in a flow-through aerated system. There were five replicate tanks per treatment. Lowest weight gain (20 g) was observed for prawns fed the diet stored at 40°C and significantly higher growth response was observed as the storage temperature decreased (30.2 g at 28–31°C; 37.7 g at 0°C and 10°C). Body size was significantly ( P P P. monodon fed with diet stored at the high temperature.