Growth performance and survivability of the Asian seabass Lates calcarifer (Bloch, 1790) reared under hyper-saline, hypo-saline and freshwater environments in a closed aquaculture system

Abstract Salinity is one of the most critical environmental parameters regarding fish physiology, modifying food intake and growth performance in many fish species. The present study has investigated the effects of different salinity levels on growth performance, feeding and survival of Asian seabass Lates calcarifer juveniles. Asian seabass juveniles were reared at 0 (T1), 5 (T2), 22 (T3), 36 (T4), and 42 (T5) ppt salinity. Approximately eight hundred thirty fish individuals with an average weight of 1.24±0.52 g were randomly distributed (166 fish/Tank) in 5 concrete tanks (each tank 30×6×4 ft, volume 19,122 L) for forty days. Juveniles were initially fed 42% crude protein-containing diets at a rate of 6% of their body weight per day. The results showed that salinity level had a significant effect on the weight gain (WG), average daily weight gain (ADWG), specific growth rate (SGR), feed conversion ratio (FCR), survival rate (SR), total biomass and health indices (p 0.05). The highest WG (39.11±1.49 g), ADWG (1.00±0.12 g), SGR (8.74±0.03% d-1) and lowest FCR (0.96±0.20) were observed with T3 treatment, which was significantly higher compared to other treatment groups (p 0.05). Among the health indices, the highest hepatosomatic index and viscerosomatic index were found with T3 treatment, significantly higher than the other groups (p 0.05). No significant differences were found among the treatments in terms of survival rate (p>0.05), but the maximum survival rate (98.89±0.0%) was observed in the T3 and T2 treatments. The maximum level of crude proteins (19.99±1.4%) was found in the whole-body biochemical composition of Asian seabass juveniles in the T3 treatment group. The second-order polynomial regression showed that 20 ppt salinity is optimum for the best growth of Asian seabass. Thus, the present study recommends 20 to 36 ppt salinity for the commercial farming of Asian seabass under a closed aquaculture system.

Resumo A salinidade é um dos parâmetros ambientais mais críticos em relação à fisiologia dos peixes, modificando a ingestão de alimentos e o desempenho de crescimento em muitas espécies. O presente estudo investigou os efeitos de diferentes níveis de salinidade no desempenho de crescimento, alimentação e sobrevivência de jovens espécies de robalos asiáticos Lates calcarifer, as quais foram criadas sob salinidade 0 (T1), 5 (T2), 22 (T3), 36 (T4) e 42 (T5) ppt. Aproximadamente 830 indivíduos de peixes com peso médio de 1,24 ± 0,52 g foram distribuídos aleatoriamente (166 peixes / tanque) em cinco tanques de concreto (cada tanque tinha 30 × 6 × 4 pés (9,1 x 1,8 x 1,2 metros), com volume de 19,12 litros) por 40 dias. Os peixes foram inicialmente alimentados com uma dieta contendo 42% de proteína bruta a uma taxa de 6% do seu peso corporal por dia. Os resultados mostraram que o nível de salinidade teve um efeito significativo no ganho de peso (GP), ganho de peso médio diário (GPMD), taxa de crescimento específico (TCE), taxa de conversão alimentar (TCA), taxa de sobrevivência (TS), biomassa total e índices de saúde (p 0,05). O maior GP (39,11 ± 1,49 g), GPMD (1,00 ± 0,12 g), TCE (8,74 ± 0,03% d-1) e o menor TCA (0,96 ± 0,20) foram observados com o tratamento T3, que foi significativamente superior em comparação com os outros tratamentos (p 0,05). Entre os índices de saúde, os maiores índices hepatossomáticos e viscerossomáticos foram encontrados no tratamento T3, significativamente superior do que os demais grupos (p 0,05). Não foram encontradas diferenças significativas entre os tratamentos quanto à TS (p > 0,05), mas a TS máxima (98,89 ± 0,0%) foi observada nos tratamentos T3 e T2. O nível máximo de proteína bruta (19,99 ± 1,4%) foi encontrado na composição bioquímica dos corpos dos jovens robalos asiáticos no grupo T3. A regressão polinomial de segunda ordem mostrou que a salinidade de 20 ppt é ótima para o melhor crescimento do robalo asiático. Assim, o presente estudo recomenda salinidade de 20 a 36 ppt para o cultivo comercial de robalo asiático em sistema de aquicultura fechado.

Growth performance and survivability of the Asian seabass Lates calcarifer (Bloch, 1790) reared under hyper-saline, hypo-saline and freshwater environments in a closed aquaculture system / Desempenho de crescimento e sobrevivência do robalo asiático Lates calcarifer (Bloch, 1790) criado em ambientes hipersalinos, hipossalinos e de água doce em um sistema de aquicultura fechado

Salinity is one of the most critical environmental parameters regarding fish physiology, modifying food intake and growth performance in many fish species. The present study has investigated the effects of different salinity levels on growth performance, feeding and survival of Asian seabass Lates calcarifer juveniles. Asian seabass juveniles were reared at 0 (T1), 5 (T2), 22 (T3), 36 (T4), and 42 (T5) ppt salinity. Approximately eight hundred thirty fish individuals with an average weight of 1.24±0.52 g were randomly distributed (166 fish/Tank) in 5 concrete tanks (each tank 30×6×4 ft, volume 19,122 L) for forty days. Juveniles were initially fed 42% crude protein-containing diets at a rate of 6% of their body weight per day. The results showed that salinity level had a significant effect on the weight gain (WG), average daily weight gain (ADWG), specific growth rate (SGR), feed conversion ratio (FCR), survival rate (SR), total biomass and health indices (p<0.05). The highest WG (39.11±1.49 g), ADWG (1.00±0.12 g), SGR (8.74±0.03% d-1) and lowest FCR (0.96±0.20) were observed with T3 treatment, which was significantly higher compared to other treatment groups (p<0.05). Among the health indices, the highest hepatosomatic index and viscerosomatic index were found with T3 treatment, significantly higher than the other groups (p<0.05). No significant differences were found among the treatments in terms of survival rate (p>0.05), but the maximum survival rate (98.89±0.0%) was observed in the T3 and T2 treatments. The maximum level of crude proteins (19.99±1.4%) was found in the whole-body biochemical composition of Asian seabass juveniles in the T3 treatment group. The second-order polynomial regression showed that 20 ppt salinity is optimum for the best growth of Asian seabass. Thus, the present study recommends 20 to 36 ppt salinity for the commercial farming of Asian seabass under a closed aquaculture system.

A salinidade é um dos parâmetros ambientais mais críticos em relação à fisiologia dos peixes, modificando a ingestão de alimentos e o desempenho de crescimento em muitas espécies. O presente estudo investigou os efeitos de diferentes níveis de salinidade no desempenho de crescimento, alimentação e sobrevivência de jovens espécies de robalos asiáticos Lates calcarifer, as quais foram criadas sob salinidade 0 (T1), 5 (T2), 22 (T3), 36 (T4) e 42 (T5) ppt. Aproximadamente 830 indivíduos de peixes com peso médio de 1,24 ± 0,52 g foram distribuídos aleatoriamente (166 peixes / tanque) em cinco tanques de concreto (cada tanque tinha 30 × 6 × 4 pés (9,1 x 1,8 x 1,2 metros), com volume de 19,12 litros) por 40 dias. Os peixes foram inicialmente alimentados com uma dieta contendo 42% de proteína bruta a uma taxa de 6% do seu peso corporal por dia. Os resultados mostraram que o nível de salinidade teve um efeito significativo no ganho de peso (GP), ganho de peso médio diário (GPMD), taxa de crescimento específico (TCE), taxa de conversão alimentar (TCA), taxa de sobrevivência (TS), biomassa total e índices de saúde (p < 0,05). O maior GP (39,11 ± 1,49 g), GPMD (1,00 ± 0,12 g), TCE (8,74 ± 0,03% d-1) e o menor TCA (0,96 ± 0,20) foram observados com o tratamento T3, que foi significativamente superior em comparação com os outros tratamentos (p < 0,05). Entre os índices de saúde, os maiores índices hepatossomáticos e viscerossomáticos foram encontrados no tratamento T3, significativamente superior do que os demais grupos (p < 0,05). Não foram encontradas diferenças significativas entre os tratamentos quanto à TS (p > 0,05), mas a TS máxima (98,89 ± 0,0%) foi observada nos tratamentos T3 e T2. O nível máximo de proteína bruta (19,99 ± 1,4%) foi encontrado na composição bioquímica dos corpos dos jovens robalos asiáticos no grupo T3. A regressão polinomial de segunda ordem mostrou que a salinidade de 20 ppt é ótima para o melhor crescimento do robalo asiático. Assim, o presente estudo recomenda salinidade de 20 a 36 ppt para o cultivo comercial de robalo asiático em sistema de aquicultura fechado.

Growth performance and survivability of the Asian seabass Lates calcarifer (Bloch, 1790) reared under hyper-saline, hypo-saline and freshwater environments in a closed aquaculture system.

Salinity is one of the most critical environmental parameters regarding fish physiology, modifying food intake and growth performance in many fish species. The present study has investigated the effects of different salinity levels on growth performance, feeding and survival of Asian seabass Lates calcarifer juveniles. Asian seabass juveniles were reared at 0 (T1), 5 (T2), 22 (T3), 36 (T4), and 42 (T5) ppt salinity. Approximately eight hundred thirty fish individuals with an average weight of 1.24±0.52 g were randomly distributed (166 fish/Tank) in 5 concrete tanks (each tank 30×6×4 ft, volume 19,122 L) for forty days. Juveniles were initially fed 42% crude protein-containing diets at a rate of 6% of their body weight per day. The results showed that salinity level had a significant effect on the weight gain (WG), average daily weight gain (ADWG), specific growth rate (SGR), feed conversion ratio (FCR), survival rate (SR), total biomass and health indices (p<0.05). The highest WG (39.11±1.49 g), ADWG (1.00±0.12 g), SGR (8.74±0.03% d-1) and lowest FCR (0.96±0.20) were observed with T3 treatment, which was significantly higher compared to other treatment groups (p<0.05). Among the health indices, the highest hepatosomatic index and viscerosomatic index were found with T3 treatment, significantly higher than the other groups (p<0.05). No significant differences were found among the treatments in terms of survival rate (p>0.05), but the maximum survival rate (98.89±0.0%) was observed in the T3 and T2 treatments. The maximum level of crude proteins (19.99±1.4%) was found in the whole-body biochemical composition of Asian seabass juveniles in the T3 treatment group. The second-order polynomial regression showed that 20 ppt salinity is optimum for the best growth of Asian seabass. Thus, the present study recommends 20 to 36 ppt salinity for the commercial farming of Asian seabass under a closed aquaculture system.

Cystic echinococcosis of livestock and humans in central Sudan.

New information was collected on cystic echinococcosis in livestock (camels, cattle and sheep) and humans in the central region of Sudan. The livestock data were collected in abattoir-based surveys in the towns of Omdurman, Tamboul and Wad Madani, between 1998 and 2001, and covered a total of 8205 animals. The highest prevalence of infection was found in the camels (44.6% of 242 infected), followed by the sheep (6.9% of 5595) and cattle (3.0% of 2368). Records were made of the sizes of the 1320 hydatid cysts detected in the livestock (907 in sheep, 71 in cattle, and 342 in camels), whether or not each cyst was fertile, and where it occurred in the body of the host. Cysts collected from cattle and camels where much more likely to be fertile (22% and 24%, respectively) than those from sheep (1%). Camels and cattle therefore appear to be the principal intermediate hosts for Echinococcus granulosus in central Sudan, whereas sheep apparently play a marginal role in transmission. In 2002, as a preliminary assessment of the public-health impact of the disease, 300 residents of a rural village 60 km west of Wad Madani were surveyed using a portable ultrasound scanner. Only one (0.33%) of the villagers investigated was found infected. The implications of these finding are discussed in terms of the various strains of E. granulosus and the role of each in human disease.

Cost saving with ultrasonography in a developing country district hospital.

OBJECTIVE: To estimate the potential monetary reduction induced by the introduction of an ultrasound unit in a major district hospital in a developing country. DESIGN: Propective study. SUBJECTS: Patients referred with abnominal diseases and pregnancy. SETTING: Wad Medani Teaching Hospital, Central Sudan. RESULTS: Local specialists referring the patients stated that an estimated 792 radiologic procedures would have been carried out to obtain the same amount of information as achieved by ultrasound. Such procedures budgeted approximately 8100 US dollars, in terms of equipment, material and personnel by 1987 rates. Such savings have benefited all departments of the hospital. CONCLUSION: The authors consider this as evidence for the fact that despite its initial high investment (15,000 US dollars), availability of ultrasound virtually reduced expenditure on other radiological diagnostic procedures. This is of special benefit for the limited budgets of hospitals in non-industrialised countries.

Echogenicity of the fetal telencephalic choroid plexus as a second trimester developmental landmark: a preliminary report.

Echogenicity of the normal fetal telencephalic choroid plexus was characterized anatomically in 102 consecutive antenatal abdominal ultrasonographic examinations. Echogenicity of the plexus was observed only during the second trimester, first appearing at week 13 and disappearing after week 23. We suggest that this echogenicity may be due to different stages of glycogen chemistry in the plexus. The knowledge that telencephalic echogenicity is confined to the second trimester should help detect diseases that cause focal areas of echogenicity in fetal life.

Patterns of skull base fracture: a three-dimensional computed tomographic study.

Three-dimensional (3D) computed tomographic (CT) reconstructions were studied retrospectively in 14 patients with skull base fractures. Our aim was to assess the clarity of visualisation and pattern of these fractures. The reformations were obtained from 3 mm thick two-dimensional (2D) CT images. The 2D data stored on optical discs were retrieved and reformatted using the scanner's software. The 3D technique could demonstrate the presence of fractures as well as 2D images. It was of special value in defining the depth and extent of fractures in the floor of the cranial fossae. Undisplaced and displaced fractures could both be demonstrated. Fractures in the anterior fossa run diagonally towards the midline and then cross the cribriform plate of the ethmoid bone. Fractures of the middle fossa run obliquely anteroposterior. Fractures in the lamina papyracea and cribriform plate were difficult to reconstruct due to the thinness of these bones and threshold definitions. The volume of the 3D block determines the angles suitable for viewing the fractures. In spite of present technical difficulties, the 3D images are of greater anatomical and diagnostic value, particularly in anterior fossa fractures. There is no additional radiation risk to the patient, since reconstructions are made from routine 2D images.

Echogenicity of the foetal telencephalic choroid plexus as a developmental landmark: a preliminary report.

Echogenicity of the telencephalic choroid plexus was observed in 34% of foetuses examined consecutively in routine obstetrical sonograms. Foetuses with echogenic were all aged between 13 and 23 weeks. 70% of the foetuses showing the echogenic plexus were in the second trimester. 80% of these foetuses were scanned during the fifth month of pregnancy (aged between 15 and 19 weeks). The biparietal diameter of 87% of the skulls with echogenic plexus ranged between 22 and 50mm. The characteristic appearance of the normal plexus during a certain period in the second trimester confirms its transient nature and suggests an underlying developmental mechanism. It appears and disappears well before the disease entities presenting in similar cephalic echogenicities.

Sonographical morphometrical findings of the liver and spleen in Sudanese patients with Schistosoma mansoni induced periportal fibrosis.

Sonographic measurements of the liver, spleen and related blood vessels were performed in 87 healthy controls and in 50 patients with periportal fibrosis (pF) as well as in 52 patients with pF and at least one episode of gastro-oesophageal bleeding due to chronic Schistosoma mansoni infection. There was a progressing shrinkage of the liver paralleled by an increasing rate of patients with a larger left than right liver lobe as involvement of pF due to S. mansoni infection progressed. This was accompanied by an increasing percentage of pathological gallbladder wall enlargement, splenomegaly and an increasing portal vein diameter. It is suggested that organomorphometrical parameters of the liver and spleen can be used for sonographical evaluation of patients with S. mansoni infection as these may be useful for their clinical assessment of the progression of disease.

Three-dimensional CT of the middle ear and adjacent structures.

Three-dimensional (3D) computed tomography of the middle ear and adjacent structures has been carried out in two cadaveric heads from axial and coronal high-resolution images. The structures shown on the images of the walls of the tympanic cavity are illustrated. The usefulness and limitations of the technique, in this region, are discussed: use of grey level volumes at the surface of the slices and the inclusion of structural landmarks is emphasized. The 3D representations show the anatomical spacial relationships of the small structures in and around the middle ear to advantage. The information may be of use in surgical orientation.

Sonographic anatomy of the rectus sheath: an indication for new terminology and implications for rectus flaps.

With the aim of standardizing descriptions of lesions on the anterior abdominal wall and definition of reconstructive flaps, the sonographic anatomy of the rectus sheath has been studied in 8 subjects. Anatomic terms have been suggested for the various segments and intersections of the sheath. The linea abla, linea semilunaris, formation of rectus sheath, segments and intersections have been described and illustrated. Identical segments and intersections were found to have characteristic sonographic features in all subjects. The intersection below the umbilicus was observed in 1 out of 8. Ultrasound capability in the determination of size and extent of tissues is discussed. It is hoped that the use of the suggested terminology and the preoperative ultrasonic definition of rectus flaps, may provide basis for objective comparison of results of reconstructive surgery.

Determination of foetal sex by ultrasound: state of the art.

The determination of foetal gender is clinically indicated in sex-linked disorders. The reliability of ultrasound in prediction during the late second and third trimesters is well-established. Few studies attained high success rate in early second trimester. The variations in the success rate are due to the difference in size and gestational age of the published samples. Most studies have concentrated on the visualization of the external genitalia. Differentiation based on internal organs is not pursued. The ethical aspects have received attention by almost all workers in this field.

PIP: Determination of fetal gender by ultrasound may be clinically indicated to rule out sex-linked disorders or a need for amniocentesis. Although ultrasound's predictive reliability in this case varies with the presentation and position of the fetus, fetal genitalia can be visualized in over 60% of examinations performed before the 18th week of gestation and in 100% of those after week 20. Before the 18th week, differentiation is more informative when the sagittal, as opposed to the coronal or transverse, view is used. Between weeks 12-14, determination can be made on the basis of a longer anogenital length in males and its higher ratio to femoral length. After the 18th week, the transverse plane is most effective in showing the penis in cross or oblique section. Through this technique, testicular descent can be observed in about 50% of male fetuses examined at weeks 28-30. In a 24-week-old fetus, the coronal view best reveals the labia and clitoris. In males, a cross section of the umbilical cord can confound findings; thus, the cord should be viewed in longitudinal section passing between the legs in front of the genitalia. To avoid termination of a healthy fetus of unwanted gender, general practice is to withhold gender information from parents unless there is a medical indication.

Sonographic changes following splenectomy for portal hypertension in Schistosoma mansoni.

Eleven patients with portal hypertension due to infection with Schistosoma mansoni underwent splenectomy and devascularization operations. The patients were examined with ultrasound once preoperatively and twice postoperatively over a period of about 6 months. Following surgery there was significant and sequential reduction in the diameter of the portal vein at the hilum and the splenic vein at the pancreas. The liver lengths and index of liver size did not change significantly. No changes in the degree of periportal fibrosis could be detected.

Hepatosplenic schistosomiasis: comparison of sonographic findings in Brazilian and Sudanese patients--correlation of sonographic findings with clinical symptoms.

Twenty-seven Brazilian and 32 Sudanese patients with hepatosplenic schistosomiasis from areas where the disease is endemic were examined with ultrasound (US). Hyperechoic periportal areas indicating periportal fibrosis (PPF) were present in all patients irrespective of their origin. Nonspecific findings were splenomegaly (all patients), gallbladder wall thickening (81% and 92%, respectively, in Brazilian and Sudanese patients), portal vein (74% and 87%, respectively) and splenic vein (59% and 70%, respectively) enlargement, and portosystemic vascular shunts (62% and 61%, respectively). The hepatic alterations were congruent and the frequency of their occurrence was similar in both patient groups. With a standardized grading system, it was shown that grade of PPF was significantly correlated with a history of bleeding from endoscopically proved esophageal varices and with distention of the portal vein as measured with US. It was concluded that sonographic grading may be used in patients with hepatosplenic Schistosoma mansoni infection who originate from completely different endemic areas.

A review of the literature on the use of ultrasonography in schistosomiasis with special reference to its use in field studies. 2. Schistosoma mansoni.

This review presents an outline of the pathology resulting from Schistosoma mansoni infections, and the ways in which it can be investigated. The use of ultrasonography is covered in detail. Ultrasonography can provide direct information about lesions in internal organs, and thus provide information about patterns of morbidity and about the regression of pathological changes after treatment. The method is non-invasive, and can be used under field conditions. Ultrasonography is valuable for the study of hepatosplenic pathology, to detect lesions such as the development of periportal fibrosis and the enlargement of the portal vein, which can indicate the development of portal hypertension. This may lead to a severe outcome, including bleeding from oesophageal varices, which is a principal cause of death from S. mansoni infection. A problem with the use of ultrasonography is that the mild lesions likely to be observed in population surveys are not always easy to assess. Ultrasonography has already been used in a number of epidemiological studies of S. mansoni infection, and has proved to be feasible and useful. However, the methodology used for ultrasound studies has varied considerably, so that it is difficult to make valid comparisons between results obtained in different places or at different times. A standardized methodology for making observations and recording the results is needed if the full potential benefit of using ultrasound in the monitoring of schistosomiasis control projects is to be realised.

Inter-observer variance in ultrasonographical assessment of Schistosoma mansoni-related morbidity in young schoolchildren.

49 Sudanese schoolchildren aged 6-9 years with Schistosoma mansoni infection were ultrasonographically examined by two independent observers in a double-blind fashion. The first observer recorded normal appearance of the liver in 23 cases, whereas the second observer recorded the appearance as normal in 33 cases. There were 23 concordant observations. For Grade I periportal fibrosis (PF), 13 observations were concordant. PF Grade II was rarely observed (2 versus 3 cases), and Grade III was not recorded at all. In total, 38 out of 49 observations were concordant (77.5%). These preliminary data from two ultrasound observers, from observations on a limited number of patients, can be seen as an indication of a potential inter-observer variation of around 20% for the distinction between the absence of PF and a low level of PF.

Radiography of the auditory ossicles: a review.

Plain films capable of demonstrating the composite shadow of the ossicular chain included the 105 degrees base, the lateral oblique of Meyer or Owen, the anteroposterior transtemporal of Chausse and the anteroposterior transorbital of Guillen. The stapes and the incudostapedial joint can not be shown with plain films. The hypocycloidal anteroposterior or Guillen is the best of tomograms and may be supplemented by lateral, inclined lateral or basal examinations. The individual ossicles, including the stapes can be demonstrated as well as the incudostapedial joint. Axial and coronal cuts with high resolution computed tomography (HRCT) demonstrate with clarity all ossicular parts commonly involved in otologic pathology. Conventional tomography and HRCT are complementary in all other temporal bone structures but the latter proved superior in ossicular visualization.

Ultrasonographic evaluation of gallbladder function in patients with Schistosoma mansoni infection.

Gallbladder function was studied in 22 patients with portal hypertension due to advanced Schistosoma mansoni infection and in 17 healthy adults. The fasting volume of the gallbladder was significantly less in patients than in controls. The gallbladder wall was grossly thickened in the study group. There was a significant difference between the patients and controls in the reduction of gallbladder volume following a fatty meal. Although the portal vein diameter and the splenic volume were significantly larger in study patients, no significant correlation could be detected between the reduction in volume or wall thickness of the gallbladder and any of the relevant sonographic features of schistosomiasis-induced portal hypertension.

The paratemporal segment of the maxillary sinus: a new sign for assessment of size.

The area of the maxillary antrum in Waters' view has been measured in 68 patients using a mechanical planimeter. The mean area was 6.04 +/- 0.25 cm2. The part of the antrum lateral to the innominate line (defined as the paratemporal segment) has a mean area of 0.72 +/- 0.07 cm2. The latter diminishes in small antra and approaches zero when the total antral area falls below 3.48 cm2. It is proposed that the innominate line (Stenvers), or its extension, descends lateral to the field of the small maxillary sinus and may be used as an additional sign of such abnormality.