Review of SEAFDEC/AQD fish nutrition and feed development research

Research on fish nutrition and feed development at SEAFDEC Aquaculture Department has focused on three major areas: nutrient requirements and their interrelationships, digestive enzymes and digestibility, and practical feed development for important species such as milkfish (Chanos chanos Forsskal), sea bass (Lates calcarifer), Nile tilapia (Oreochromis niloticus), bighead carp (Aristichthys nobilis), and tiger shrimp (Penaeus monodon). Early studies on the nutrient requirements were mainly on protein, lipid and carbohydrate. Studies on essential amino acids and fatty acids, and optimum proteln:energy ratio in the diets for cultured species were conducted later. Likewise, requirements for other essential nutrients in shrimps, like phospholipid and cholesterol, were studied. Dietary calcium and phosphorus required to prevent soft-shelled shrimps were determined. Requirements for water-soluble vitamins and bioavailability of stable forms of vitamin C were evaluated. Little is known of the vitamin and mineral requirements.The major digestive enzymes in milkfish have been studied. The apparent digestibility of common feedstuffs were determined in vivo and in vitro for milkfish and tiger shrimp, and presently, for sea bass. Development of cost-effective practical feed continues to be a major research undertaking at SEAFDEC/AQD. Diet refinement emphasizes on use of inexpensive and indigenous materials in diet formulations. The feasibility of using legumes, leaf meals, and agricultural by-products and wastes as feed components has been demonstrated. Feed and feedstuff quality control and proper processing techniques were found to improve the nutritional value of low-grade raw materials. Improved feeding techniques and practices have been pursued to minimize feeding costs. Studies on the effect of feeds on the environment are being initiated. Economically feasible grow-out diets for semi-intensive culture of milkfish, Nile tilapia, and tiger shrimp, and diets for broodstock and larvae of these species have been developed

Immune and bacterial toxin genes expression in different giant tiger prawn, Penaeus monodon post-larvae stages following AHPND-causing strain of Vibrio parahaemolyticus challenge

Acute Hepatopancreatic Necrosis Disease (AHPND), a disease caused by Vibrio parahaemolyticus (V-PAHPND), kills Penaeid shrimps worldwide, resulting in severe economic losses during aquaculture. To further understand how Penaeus monodon post-larvae (PL) respond towards infection of this pathogenic bacterium, the expression of several important immune and bacterial toxin genes in three stages of P. monodon PL (PL15, PL30 and PL45) upon V-PAHPND challenge, were determined. A 20-hrs challenge test with 2.7 x 10(7) cfu ml(-1) of V-PADPND resulted 81, 65 and 1.7% mortality respectively for PL30, PL15 and PL45, indicating that PL30 was most vulnerable to V-PADPNEP The immune response of shrimp PL at this stage was robust, with Toll-like receptor (TLR), prophenoloxidase (proPO), lysozyme (lyso) and penaeidin (PEN) augmented approximately 10.7, 4.7, 6.5 and 3.2-fold, respectively. The expression initiated at one hour post-infection (h.p.i), peaked at 16 h.p.i and 20 h.p.i, and decreased at 18 h.p.i, indicating the crucial involvement of these immune related genes in the defence and recovery of the first-line defence mechanisms during V-PADPND infection. This work also revealed that toxR gene represents a good indicator gene for Vibrio detection whereas PIR A, for V-PADPND pathogenicity determination of P. monodon. Overall, these findings provided novel insights into the immune response and V-PADPND No susceptibility of different P. monodon PL stages during infection, with outcomes potentially useful in enhancing the application of health therapy and biosecured aquaculture practices to minimize the damaging risk of AHPND towards sustainable production of P. monodon

Use of enriched live prey in promoting growth and maturation of tiger shrimp (Penaeus monodon)

This study was undertaken to determine the effect of nutritional management of broodstock of Penaeus monodon on growth and maturation. Test specimens were obtained from a grow-out pond before attainment of maturity and were reared in hatchery tanks. Four types of dietary treatments (M1–M4) were given to separate batches that were run in duplicate. Feeding trials continued for five months. A diet with live bloodworm, bioencapsulated to contain tricalcic phosphate as its major component, was found to be the most efficient. Specimens of this particular batch assimilated food more efficiently, grew at a faster rate and attained maturity earlier than other groups. Bloodworm provided the lipid fractions for which there is no de novo synthesis in shrimp. The enrichment product acted by promoting somatic growth and increasing transfer of biochemical constituents needed by the ovary for develo

Effect of temperature and salinity on the hatching of eggs and larval development of sugpo, Penaeus monodon

Abstract only.Incubation of Penaeus monodon eggs and rearing of different larval stages were undertaken at nine temperature-salinity combinations. The eggs, nauplii, zoea and mysis from one spawner kept as stock culture at ambient temperatures of 26-30°C and salinity of 32-33 ppt were exposed to temperature levels of 23, 28 and 33°C and salinity levels of 23, 28 and 33 ppt. Eggs and nauplii survived the sudden change of temperature and salinity (from ambient to experimental) but the zoea and mysis did not. However, salinities of 23 and 28 ppt in combination with any of the temperature levels produced weak larvae. Highest mean hatching rate was obtained at the temperature-salinity combination of 23°C-33 ppt, followed by 28°C-33 ppt and 33°C-33 ppt. Incubation periods for these treatments were 22, 16 and 14 hr, respectively. Survival rate of nauplius (taken from stock cultures) to first zoeal stage was highest at 28°C-33 ppt, followed by 33°C-33 ppt and 23°C-33 ppt with molting time of 50, 45 and 75 hr, respectively. The nauplii exposed to 33°C-33 ppt molted to zoea stage within 38 to 40 hr but later died. Those exposed to 23°C-33 ppt and 28°C-33 ppt reached zoea stage within 57 to 60 hr and 48 to 50 hr, respectively. Similarly, the nauplii taken from the stock cultures and reared until postlarval stage (P1) under experimental conditions completed the zoea and mysis stages in 9 to 11 days at 28°C C-33 ppt, 7 to 9 days at 33°C-33 ppt, and 13 to 15 days at 23°C-33 ppt. Statistical analysis showed that salinity had highly significant effect on rates of hatching of eggs and survival from nauplius to first zoeal stage but not temperature although the latter had an apparent effect. However, both factors affected time of hatching of eggs and time of molting from nauplius to zoea. Interaction effect was significant only on rate and time of hatching. Different sources (spawners) of eggs and nauplii did not have significant effect on time of hatching and molting from nauplius to zoea, but significantly affected the hatching rate of eggs and survival rate of nauplii to zoea stage

The scope of the crustacean immune system for disease control

The culture or wild capture of marine and freshwater shellfish, including crustaceans, is without doubt a key source of protein for a burgeoning world population. Historically the expansion of aquaculture has, however, been accompanied by the increased incidence of economically significant diseases, most notably of viral and bacterial origin. Since the late 1970s great progress has been made in our understanding of the generalized protostome innate immune system. Distinct pathways, pathogen receptor proteins and effector molecules have since been identified that are not ancestral or homologous to those of the deuterostomes, including vertebrates. Within the past decade progress has accelerated with the rapid characterisation of new classes of recognition proteins, immune effectors and regulatory pathways. This paper provides a broad overview of our current understanding of invertebrate immunology, taking the crustacean decapod immune system as its focus. Recent developments in the field are described briefly and their implications and potential considered. These advances offer fundamental new insights in our efforts to understand disease in cultured populations and also to develop knowledge of environmental effects on host/pathogen interactions within a fishery context. Of course, challenges do remain, including the lack of an immortal cell line and the limited publically-available genomic resources. These are considered in this review as priorities for future research effort. With the continued application of more insightful technologies, coupled with associated investment, it is expected that the speed at which some of these issues are resolved will accelerate

Penaeus monodon Shell Powder Extract as A Candidate for Dental Material Restoration

The prevalence of dental caries in Indonesia is still high. One of the dental caries treatments is direct restoration. Biomaterial, often used as a restorative material, is glass ionomer cement which has a silica content of 35%. Silica is found in Penaeus monodon shells which have been a waste of production. This research aims to study the characteristic of Penaeus monodon shell powder extracts as candidates for dental materials restoration. The research sample used was Penaeus monodon shell powder extract which was then carried out by a depigmentation process by mixing acetone 1:10 (w/v) ≤ 20 hours. Samples were tested with the XRD test (x-ray diffraction). SEM assessment was performed to evaluate the morphology of the particle. Data were analyzed using Mann-Whitney. The result demonstrated a significant silica content in Penaeus monodon shell powder extract before and after the depigmentation process with a p-value of 0,00 (p0,05). The depigmentation process can decrease silica content in Penaeus monodon shell powder extract. There was a different comparison of silica content in Penaeus monodon shell powder extract before and after depigmentation as a candidate for dental materials restoration

Use of enriched live prey in promoting growth and maturation of tiger shrimp (Penaeus monodon)

This study was undertaken to determine the effect of nutritional management of broodstock of Penaeus monodon on growth and maturation. Test specimens were obtained from a grow-out pond before attainment of maturity and were reared in hatchery tanks. Four types of dietary treatments (M1–M4) were given to separate batches that were run in duplicate. Feeding trials continued for five months. A diet with live bloodworm, bioencapsulated to contain tricalcic phosphate as its major component, was found to be the most efficient. Specimens of this particular batch assimilated food more efficiently, grew at a faster rate and attained maturity earlier than other groups. Bloodworm provided the lipid fractions for which there is no de novo synthesis in shrimp. The enrichment product acted by promoting somatic growth and increasing transfer of biochemical constituents needed by the ovary for development.Shrimp culture, Feeding experiments, Nutritional requirements, Diets, Growth, Sexual maturity Penaeus monodon

Factors determining spawning success in Penaeus monodon Fabricius

Spawning success in relation to the size of spawner, clumping of eggs, percentage of spawning and frequency of spawning was studied in Penaeus monodon collected off Tamil Nadu, India. The results indicated positive correlation between the size of spawner and the fecundity and hatching percentage, but not the start of hatching. Hatching characteristics were influenced by clumping of eggs or abortive spawning; the greater the clumping, the longer the time taken for hatching, resulting in a lower hatching percentage. The start of hatching time increased when the frequency of spawning increased. Lower hatching rate was observed as the frequency of spawning increased

Evaluation of artificial feeds for shrimp (Penaeus monodon) production in brackishwater ponds

Abstract only.The experiment was conducted in fifteen 500-m2 brackishwater ponds to determine the response of Penaeus monodon juveniles fed with various artificial diets. Five treatments with three replicates each were: two commercial feeds containing 45% and 40% crude protein (treatments I and II), two experimental diets formulated to contain 35% crude protein (treatments III and IV) and control, without feeding (treatment V). Shrimp were fed twice daily at feeding rates based on shrimp consumption. Highest mean harvest weight was attained in treatment I (23.47 g) > III (19.25 g) > II (18.86 g) > IV (11.29 g) > V (9.27 g). Statistical analysis showed that differences in growth were significant at 5% probability level. However, growth in treatments I, II and III are comparable, also growth in treatments II, III and IV. Growth in treatments I, II, III and IV was significantly different from treatment V. Highest mean survival was attained in treatment III (91.82%) > I (88.93%) > II (86.95%) > IV (83.62%) V (82.62%). Statistical analysis showed no significant differences among treatments at 5% probability level. Projecting on a hectare basis, mean yield for each treatment was: I (628.37 kg) > II (496.35 kg) per crop in 120 days culture. Good yield was attributed to provision of formulated feeds, use of pumps in addition to tidal change for water exchange and control of predators, and pest eradication through proper pond preparation