Survival, Growth and Production of Penaeus monodon in Modified- Extensive and Semi Intensive Culture Systems of Andhra Pradesh, India

An analysis was made on the stocking density, survival, growth and production of Penaeus monodon in semi intensive (SI) and modified extensive (ME) shrimp culture ponds located in East Godavari district of Coastal Andhra Pradesh, India. Survival of shrimp in the ME systems with low stocking densities is higher (56 - 88%) than in the SI systems (12.3 – 52%) with higher stocking densities. Growth of shrimp is dependent not only on the stocking density but also on the management practices. Although the percent survival is more in ME system the growth is much faster in SI system owing to better management practices. Weight gain of shrimp was more rapid in the SI system than in the ME system initially up to 90 days of culture (DOC) but the trend was reverse in the later age of culture period. The optimum stocking density for achieving maximum production in the area is suggested as 10-15 individuals / m2 in SI ponds and 3-5 individuals / m2 in ME ponds

Characterization of Vibrio spp. associated with Diseased Shrimp from Culture Ponds of Andhra Pradesh(India)

Surveys undertaken on diseases caused by Vibrio spp. in Penaeus monodon from culture ponds of coastal Andhra Pradesh recorded the occurrence of five types of diseases : tailnecrosis,shelldisease,reddisease,looseshellsyndrome(LSS), and white gut disease(WGD). Amongthese,LSS,WGD,and red disease caused mass mortalities in shrimp cultureponds. Six species of Vibrio V.harveyi,V.parahaemolyticus,V.alginolyticus,V.anguillarum,V.vulnificus,and V.splendidus are associated with the diseased shrimp. The number of Vibrio spp. associated with each disease ranged from two to five. Additionally,shrimp with red disease had concurrent infections with white spot syndrome virus.Vibrio harveyi in the case of LSS and WGD, V. parahaemolyticus for reddisease, and V.algino-lyticus for shell disease are the major etiologcalagents. Differences occur in the degree of virulence of different species of Vibrio and also different isolates of the same species. Vibrioharveyi isolated from LSS shrimp is the most virulent.Ingeneral, allthe Vibrio isolates from LSS shrimp tend to be more virulent as compared to their counter parts fromo the diseased shrimp.It is apparent that the degree of virulence of various Vibrio isolates depends on its source and the pond environmental conditions. Most of the Vibrio isolates showed susceptibility to oxy-tetracycline, norfloxacin, and ciprofloxacin. The luminous V.harveyi exhibited resistance to many antibiotics and susceptibility to only three drugs. Considering the emergence of antimicrobial resistant strains of Vibrio, the need for using probiotics in place of antibiotics for disease control is stressed

Characteristics, Pathogenicity and Antibiotic Sensitivity of Bacterial Isolates from White Spot Diseased Shrimp

A bacteriological study was undertaken on white spot diseased shrimp collected from extensive, modified-extensive and semi-intensive ponds located at Visakhapatnam and East Godavari districts of North Coastal Andhra Pradesh. The diseased shrimp exhibited white spots and red discoloration of the body. Four species of bacteria, V. alginolyticus, V. parahaemolyticus, V. anguillarum and Pseudomonas aeruginosa were isolated from the hemolymph of the diseased shrimp. V. alginolyticus was found to be the most dominant and virulent species. All the bacterial isolates showed sensitivity towards oxytetracycline which is a commonly used antibiotic in culture ponds

Biochemical Constituents of Shrimps from Semi-Intensive and Modified-Extensive Culture Ponds

A quantitative study on the occurrence of major biochemical constituents including protein, carbohydrate, lipid and cholesterol in the muscle of different growth stages of Penaeus monodon collected from semi-intensive (SI) and modified-extensive (ME) culture ponds of coastal Andhra Pradesh, adopting different feeding schedules was undertaken. The objective was to determine the effects of the age of shrimp and the stocking density on the biochemical composition of the muscle. Protein was found to be the major biochemical constituent and an increase in protein content with advancement of shrimp age was recorded. Glycogen occurred only in traces. Lipid and cholesterol occurred in moderate quantities with concentrations slightly higher in shrimps of SI ponds as compared to those of ME ponds. Overall, the stocking density had little impact on protein and glycogen concentration in the muscle

Collaural fistula: a case report

Cervico-aural [collaural fistula] fistula is rare and it accounts for less than 5% of branchial cleft anomalies. In this paper, we report one such case of a 9 year old girl who was presented to us with two discharging cutaneous openings on the right side; one in the floor of the external auditory canal and another in the neck at the junction of the upper 2/3rd and lower third of the sternomastoid muscle along its anterior border

Reduced In-Plane, Low Frequency Helicopter Noise of an Active Flap Rotor

Results from a recent joint DARPA/Boeing/NASA/Army wind tunnel test demonstrated the ability to reduce in-plane, low frequency noise of the full-scale Boeing-SMART rotor using active flaps. Test data reported in this paper illustrated that acoustic energy in the first six blade-passing harmonics could be reduced by up to 6 decibels at a moderate airspeed, level flight condition corresponding to advance ratio of 0.30. Reduced noise levels were attributed to selective active flap schedules that modified in-plane blade airloads on the advancing side of the rotor, in a manner, which generated counteracting acoustic pulses that partially offset the negative pressure peaks associated with in-plane, steady thickness noise. These favorable reduced-noise operating states are a strong function of the active flap actuation amplitude, frequency and phase. The associated noise reductions resulted in reduced aural detection distance by up to 18%, but incurred significant vibratory load penalties due to increased hub shear forces. Small reductions in rotor lift-to-drag ratios, of no more than 3%, were also measure

Multiple Antibiotic Resistance pattern of Vibrio harveyi from Luminous Vibriosis affected cultured Tiger Shrimp, Penaeus monodon in Andhra Pradesh, India

An investigation was undertaken to determine the extent of antibiotic resistance exhibited by Vibrio harveyi, isolated from diseased Penaeus monodon, collected from culture ponds located in East Godavari District of Andhra Pradesh. A total of 159 isolates of Vibrio harveyi, of which 110 are from four Modified-Extensive ponds (ME1, ME2, ME3, ME4) and 49 are from four Semi-Intensive ponds (SIA, SIB, SIC, SID), were screened for their susceptibility to 22 antibiotics. All the isolates from ME and SI ponds were resistant to penicillin G and 100% susceptibility was observed in the case of all the isolates of ME ponds towards Ciprofloxacin and Norfloxacin. The isolates from ME ponds were more resistant than those from SI ponds and the isolates of ME 1 pond exhibited 100% resistance towards eight antibiotics, whereas those of SI ponds were 100% resistant to only one antibiotic. A significant difference was observed in the Multiple Antibiotic Resistance (MAR) of the isolates from ME ponds, whereas the difference was not significant in the case of isolates from SI ponds. MAR against 4 - 10 antibiotics was highest in the isolates from pond ME 4 (90.5%), followed by those from ME 3 (76.7%) and ME 2 (11.4%) and it was highest with 40 % in the isolates from SI D pond. The study revealed the occurrence of highly virulent strains of Vibrio harveyi in shrimp culture ponds, which developed resistance to many antibiotics due to indiscriminate usage of antibiotics

Probiotic activity of Pseudomonas aeruginosa (PIC-4) isolated from Visakhapatnam coast, Bay of Bengal, India, against Vibrio harveyi in Penaeus monodon

Pseudomonas aeruginosa (PIC 4), isolated from coastal waters of Visakhapatnam (Gen Bank Accession no: KF803248) was tested for its antagonistic activity against Vibrio harveyi as probiotic in cultured Penaeus monodon. Pseudomonas aeruginosa PIC 4 has proved to be non-pathogenic to the shrimp by pathogenicity tests. Vibrio counts in probiotic fed shrimp and the surrounding water medium were significantly lower when compared to the control group of shrimp and water during 50 days of culture. Mean weight of probiont fed shrimps after 50 days of culture was (2.21 + 0.15 g) , significantly higher than that of normal diet fed ones (1.33+0.18 g). Survival percent was also significantly higher in probiont fed shrimp (47.33% + 5.55%) than that of the control diet fed shrimp (26.33% + 7%). Percent survival in probiotic fed and normal diet fed shrimp after the challenge with V. harveyi was 93.04 and 38.87 respectively

Occurrence of concurrent infections with multiple viruses in Penaeus monodon from culture ponds of north coastal Andhra Pradesh

A histopathological study of Penaeus monodon show-ing external symptoms of white spot disease, collected from culture ponds at Mulakuddu and Rambilli villages (Visakhapatnam District) during May and July 2001, provided evidence for the occurrence of multiple viral infections. Each diseased shrimp carried concurrent infections with four different viruses, identified on the basis of nuclear changes, resulting in the formation of characteristic inclusion/occlusion bodies, as WSSV, YHV, MBV and IHHNV. The iden-tification of the various viruses needs confirmation through molecular diagnostic methods. This consti-tutes a report recording concurrent infections with multiple viruses in a single shrimp

Blade vortex interaction noise reduction techniques for a rotorcraft

An active control device for reducing blade-vortex interactions (BVI) noise generated by a rotorcraft, such as a helicopter, comprises a trailing edge flap located near the tip of each of the rotorcraft's rotor blades. The flap may be actuated in any conventional way, and is scheduled to be actuated to a deflected position during rotation of the rotor blade through predetermined regions of the rotor azimuth, and is further scheduled to be actuated to a retracted position through the remaining regions of the rotor azimuth. Through the careful azimuth-dependent deployment and retraction of the flap over the rotor disk, blade tip vortices which are the primary source for BVI noise are (a) made weaker and (b) pushed farther away from the rotor disk (that is, larger blade-vortex separation distances are achieved)