Shrimp (Penaeus monodon Fabricius) production in brackishwater ponds applied varying fertilizer combinations

Details are given of the production of Penaeus monodon in the Philippines reared in brackishwater earthen ponds applied with different fertilizer combinations, namely diammonium phosphate, urea and chicken manure. Results show that the shrimp showed higher yields in fertilized ponds, but increasing the concentration of fertilizers did not give a marked increase in yield - the excess fertilizer was wasted.

Agiis: a bivalve cultivated as live shrimp feed

Live 'agiis' have been proven to be a good feed for shrimp for the past ten years by polyculture fish farmers in the province of Capiz, in the island of Panay, west central Philippines. A brief account is given of culture and feeding operations. Its cultivation period is short and seeds are readily available. It can reduce dependence on trash fish which is now getting to be scarce; it also seems much cheaper. Perhaps this fast-growing tiny bivalve can be scientifically investigated by students of aquaculture as feed for other commercial aquaculture species. Its scientific identification can be a good start.

Detection of viral diseases in shrimp Litopenaeus vannamei in Iran with emphasis on white spot disease prevention by using marine alga extract

Nowadays, following was expanded shrimp breeding and culture; viral diseases have been main problem which threatened shrimp industry in the country. Therefore, shrimp samples were obtained from different stages of Litopenaeus vannmei life cycle (larval, post larval, juveniles, adults and broodstocks) based on clinical signs in the breeding center and shrimp farming from Bushehr, Khozestan and Sistan and Baluchestan provinces. Viral diseases were detected by PCR (Polymerase Chain Reaction), histopathology and transmission electron microscopy (TEM) methods. Results of the PCR were indicated present white spot virus (WSV) in juveniles, sub adults and adults shrimp with medium intensity from three provinces, but it was not showed in larval and post larval stages. Histopathological sections were indicated hypertrophy and basophilic Cowdry type A formation in nucleus cells of gill, haematopoietic, lymphoid and epithelial's cuticles and intestinal tissues which was associated with small vacuoles increased in B cells of hepatopancreas tissue of infection shrimps. Transmission electronic microscopic studies were demonstrated that the length and diameter virus was detected, respectively, 300 ± 20 nm and 75 ± 5 nm. Considerable, results of the PCR were only displayed IHHNV in juvenile, adult and broodstock shrimps from breeding and farming center of Bushehr province. The main lesion pathology was formed eosinophilic Cowdry type A in nucleus cells of gill, haematopoietic, lymphoid and epithelial's cuticles and intestinal tissues. Whereas penaeid shrimps are lack specific immune system, hence, in the present study was used of marine alga (Lurensia snideria) collected from along costal Persian Gulf of Bushehr province for viral diseases were prevented. Powder alga extract were added with a ratio of 1 % to shrimp diet. Total haemocyte count (THC) and total protein plasma (TPP) were increased after 5 days of oral administration diets. When shrimps were infected by with spot virus experimentally, THC and TPP gradually were increased in both two groups (shrimps fed with diet containing alga extract and without alga extract) after 48h. Nevertheless; THC, TPP and survival of shrimp fed with diet containing alga extract were more than shrimp control in 15 days. So, oral administration Lurensia snideria extract was capable prevention infected L. vannamei via stimulant specific immune system.

Investigation on possibility of survival and growth enhancing by selected seaweeds from Persian Gulf in post larvae shrimp Litopenaeus vannamei

The use of antibiotics in aquaculture has been limited. Scientifics seeking for natural substitutes to prevent of aquatic animals diseases. Considering seaweeds are rich of nutritions and bioactive compounds, the purpose of this study is: investigation the potential and use possibility of native seaweeds from Persian Gulf in shrimp aquculture industry to improve growth, survival of postlarvae and to resistance against pathogens such as vibriosis. For this propose 7 macroalgae species from Bushehr province coast, inclouding: green algae (C. iyengarii), brown algae (S. angutifolium and S. ilicifolium) and red algae (L. snyderiae, K. alvarezii and G. corticata) were collected and identified. Then seaweed extracts abtained by Water, Ethanol, Methanol and Chloroform solvents by soaking method. In vitro antibacterial activity of extracts against Gr+ bacteria (S. aureus and B. subtilis) and Gr- bacteria (V. harveyi, V. alginolyticus and E. coli) was conducted by Agar diffusion, MIC and MBC methods. Antioxidant activity also by DPPH and EC50 methods was investigated. According to results of these two tests four seaweeds species (S. angutifolium, L. snyderiae, K. alvarezii and G. corticata) were selected for use in shrimp postlarvae (PL22) diets by Bio-Encapsulation (Artemia enrichment). Before of enrichment, toxicity effect of extracts to Artemia nauplii were evaluated by determination of LC50 24 h method. From results of this section Ethanol extracts were selected to bioencapsulation. After encapsulation shrimp postlarvae divided to 12 groups in triplicate, namely: C-, C+, S (200), S (400), S (600), L(200), L(400), L(600), G(300), G(600), K(300) and K(600). During 30 days of reared period C- and C+ use of basal diet and unenriched Artemia, but the other groups use of basal diet and enriched Artemia. Except C-, the shrimps in first day of culture put in 107 cfu/ml v. harveyi suspension for 30 minutes, and after water exchange 10 ml of this dose was added to reared aquaria. After 30 days survival percentage, obtained weight and SGR% were investigated. To evaluate vibrio loading, every 10 days 5 postlarvae were sampled randomly for vibrio count. Results showed that vibrio count in C- was less than the others and in C+ was more than the others. In treatments vibrio count in L(200) was the most and L(600) was the less. Survival rate in C- was the most and after that G(600) with 79.4±6.6% and then S(300) and K(600) were 73.3±7.3% and 70.6±6.6% respectively that were significantly compare the other (P < 0.01). Also the C+ was the less with 33.3±6.6% that difference was significant (P< 0.01). In this study growth parameters of all groups that fed by enriched Artemia were better than C+ (P<0.05). After cultre period 10 shrimp of every aquarium disinfected and reared for 10 days like before treatment. After 10 days the shrimps were challenged by 3×108 cfu/ml V. harveyi and mortality was recorded for 7 days. The all of animals in C- were survive but more than 90% of C+ were dead. And survival in all of treatments were better the C+ (P<0.05). The study showed the ethanol extracts of selected seaweed from Persian Gulf is a good source for growth, Survival and disease control in shrimp larviculture.