Spermatophore cryopreservation and artificial insemination of black tiger shrimp, Penaeus monodon (Fabricius)

To develop an appropriate cryopreservation protocol for spermatophores of black tiger shrimp, Penaeus monodon, three cryoprotectants (dimethyl sulphoxide (DMSO), methanol (MeOH) and ethylene glycol (EG)) at two concentrations (5% and 10%) were examined. Artificial implantation of spermatophores was also carried out to assess the fertilizing ability of fresh and post‐thaw spermatophores. Spermatophores were collected during consecutive regenerations (15‐day intervals) and assessed for qualitative and quantitative changes and also for fertilizing ability by implantation. The mean fertilization rate for artificial insemination using post‐thaw spermatophore was 79.9±3.7%, lower than the fertilization rates observed for artificial implantation using fresh spermatophore and natural mating. Mean hatch rates for fresh spermatophore, frozen‐thawed spermatophore and natural mating were 88.8±0.6%, 87.8±0.4% and 88.3±0.5%, respectively; and there was no difference among the three groups. The mean fertilization rate of spermatophores collected during the first stripping was higher (90.6±0.6) than during the second stripping (85.7±2.6), but the mean hatch rate was not different between the two strippings. The highest mean sperm viability (79.7±0.4%) was obtained from DMSO (5%), with no survival observed in the 10% MeOH treatment. Spermatophore weight, total sperm count and percentage of abnormal sperm were not different between spermatophores collected at the first and second stripping. This is the first study to report high fertilization and hatch rates from cryopreserved spermatophore using artificial implantation of spermatophore before spawning.     

Zingiber officinalis an herbal appetizer in the tiger shrimp Penaeus monodon (Fabricius) larviculture

Penaeus monodon postlarvae were fed with different percentages (0%, 25%, 50%, 75% and 100%) of the herbal appetizer Zingiber officinalis enriched Artemia. After 30 days of culture (i.e. PL‐1–30), a very positive result was found in Z. officinalis‐enriched Artemia‐fed postlarvae. The unenriched Artemia‐fed postlarvae consumed 91.0 mg/animal/30 days of feed, whereas the Z. officinalis‐enriched Artemia increased their consumption to 127.9 mg/animal/30 days. A similar pattern was noticed in feed absorbed (110.2 mg), dry weight growth (26.7 mg) and feed catabolized (83.2 mg) in Z. officinalis‐enriched Artemia because of enzymatic activities. The conversion efficiency of unenriched postlarva was 17.19%, whereas in 100%Z. officinalis‐enriched Artemia, the maximum conversion efficiency was 20.85%. The net production efficiency increased significantly (P < 0.05) to 22% from that of the unenriched Artemia‐fed postlarvae. The administration of Z. officinalis in all levels produced significantly (P < 0.05) higher weight gain and specific growth rate. The utilization efficiency of feed increased proportionately to the percentages of Z. officinalis. Digestive enzyme activity (amylase, protease and lipase) increased significantly (P < 0.05) in the 50%, 75% and 100% enrichment. Among the different percentages of enrichment, the 100%Z. officinalis‐enriched Artemia‐fed postlarvae performed better in the overall status.     

The use of passive acoustics to measure feed consumption by Penaeus monodon (giant tiger prawn) in cultured systems

The feeding inefficiencies associated with intensively cultured prawn systems have a significant financial cost and environmental impact. Initial trials of a commercial system using sound to manage feeding within cultured systems have achieved promising results with an impressive food conversion (food weight/biomass) ratio of 1.42. Whilst these results demonstrate the potential benefit of employing passive acoustics for feed management, the underlying technologies are not well understood by industry or the research community. Consequently, a sound based study of feeding tiger prawns is conducted to investigate the key challenges associated with passive acoustic approaches; sound detection and feed demand estimation. The study finds that tiger prawns produce impulsive sound signatures during feeding that can be used as a proxy of feeding activity. Spectral features of the feeding signatures can be used to detect feeding activity within acoustically complex farm ponds (feeding signal to noise ratios less than −40 dB), given they are largely disjoint from the background noise spectrum (aerators) across all farm recordings. One of the potential challenges identified with sound based feed detection is that other sources of event driven interference arise (i.e. rain and faulty aerators), which can be misclassified as feeding. Whilst our investigation indicates that sound based detection of feed events are plausible, it is unclear how accurate it is to estimate the quantity of consumed pellets from feeding sound. Our study provides evidence to support its feasibility, given the temporal evolution of feeding sounds and pellet consumption were linearly related across tank and pond based feeds, respectively (R² = 0.95 and R² = 0.96).     

Effect of Penaeus monodon-type baculovirus (MBV) on survival and growth of larval Penaeus monodon Fabricius

Abstract. The present study attempts to investigate the effect of Penaeus monodon -type baculovirus (MBV) infection on growth and survival of the larval stages of Penaeus monodon Fabricius. The results showed that MBV may significantly retard larval growth and cause mortalities during the larval stage. The MBV-infected larvae of P. monodon varied more in body size than uninfected control shrimp, and were discoloured. To detect the presence of MBV in larval prawn, histopathological techniques and an enzyme-linked immunosorbent assay ( elisa ) were used. Positive diagnoses were routinely detected as early as the zoea 1 stage when ELISA was used.     

Fusarium incarnatum isolated from black tiger shrimp, Penaeus monodon Fabricius, with black gill disease cultured in Vietnam

Fusarium incarnatum was isolated from gill lesions of cultured black tiger shrimp, Penaeus monodon, in every crop during 2000-2002 in Nghe An province, Vietnam. Infected shrimps showed typical signs of black gill disease and mortalities about a month prior to harvest. Detailed morphological examinations, as well as molecular phylogenic analyses based on partial nucleotide sequences of ribosomal DNA, were made on the isolates. An artificial infection of kuruma prawn, Penaeus japonicus, using two selected isolates was also conducted and their pathogenicity determined.     

Effects of dietary mannan oligosaccharide on growth,survival, physiological,immunological and gut morphological conditions of black tiger prawn (Penaeus monodon Fabricius 1798)

The aim of this experiment was to determine the effects of dietary inclusion with mannan oligosaccharide (Bio‐Mos, Alltech, Nicholasville, KY, USA) on growth, survival, physiological and immunological conditions and gut morphology of the black tiger prawn (Penaeus monodon). Five diets supplemented with MOS at 0 g kg^?1 (control diet), 1, 2, 4 and 8 g kg^?1 were fed to the prawn juveniles (0.4 ± 0.06 g, total weight) for the duration of 63 days. Growth was the highest (P < 0.05) when the prawns were fed the 1 g kg^?1 MOS included diet. Wet tail muscle index (Tw/B), dry tail muscle index (Td/B) and tail muscle protein (Tmp) were higher (P < 0.05) in the prawns fed MOS included diets MOS compared with the prawns fed the control diet. Total haemocyte counts (THCs) of the prawns fed MOS included diets were higher (P < 0.05) than THCs of the prawns fed the control diet. Epithelium layer and epidermal cell density of the gut of the prawns fed 1 g kg^?1 and 2 g kg^?1 MOS diets were better than the prawns fed the control and other MOS diets. The results imply a positive effect of dietary supplementation of 1–2 g kg^?1 MOS in the culture of black tiger prawns.     

Pathological changes in the tiger prawn, Penaeus monodon Fabricius, associated with culture in brackishwater ponds developed from potentially acid sulphate soils

Abstract. Abnormal brown discoloration of the gills, soft shells and decreased survival were identified among problems affecting Penaeus monodon Fabricius adults cultured in growout ponds developed from potentially acid sulphate mangrove soils in Johor, Malaysia. A histological and ultrastructural study showed that lamellar ferric hydroxide accumulation and associated gill changes, which led to hypoxic damage in other tissues, were probably responsible for many of the clinical abnormalities observed in the prawns.     

Detection of Penaeus monodon-type baculovirus (MBV) infection in Penaeus monodon Fabricius by in situ hybridization

Abstract. A digoxigenin-labelled DNA probe was used for in situ detection of the Penaeus monodon -type baculovirus (MBV) derived from cloned MBV polyhedrin genome in cultured Penaeus monodon Fabricius. First, the specificity of the probe against MBV DNA with dot blot hybridization analysis was verified. This probe indicated that cloned MBV polyhedrin fragment can be used as an MBV-specific probe. This was then used to microscopically examine sections of MBV-infected tissues for a blue-purple precipitate indicative of a positive reaction for MBV. MBV-positive cells were located only in the epithelium of the hepatopancreatic tubules and of the midgut. Furthermore, comparison of the susceptibility to MBV infection among several life-stages of the shrimp showed that the MBV genome was found in the zoea, mysis, post-larva, and adult stages, whereas MBV DNA was not detected in either eggs or nauplii. The results were quantified from in situ hybridization with an image analyser to compare the degree of cell infection among groups of cultured P. monodon collected from various farms in Taiwan.     

Penaeus monodon (Fabricius) and Penaeus merguiensis (de Man) biculture in East Java, Indonesia

Shrimp farmers in South-East Java have recently observed a decline in Penaeus monodon (Fabricius) production. To stabilize overall production, some farms have switched partially to biculture of P. monodon and P. merguiensis (de Man). The production from 33 ponds in two of these farms was analysed. In addition, the water quality in 10 ponds was monitored over the entire culture period. Information was also available on the post-larvae (PL) source and feed used per pond. Water quality remained stable during the culture period and there was no accumulation of organic material during the second half of the culture period. Stocking P. merguiensis 2 months after P. monodon partially compensated for the low production of P. monodon, thereby stabilizing overall production. When the production of P. monodon is low, the production of P. merguiensis is high and vice versa (P<0.001). Feed source had no effect on production when stocking density was included as a covariable in the analysis (P > 0.05), while P. monodon PL source caused production to differ by a factor of three (P<0.001). It was concluded that biculture of P. monodon and P. merguiensis is an effective way to stabilize overall shrimp production.     

Effect of high pressure and heat treatments on black tiger shrimp (Penaeus monodon Fabricius) muscle protein

International Aquatic Research - Osmo- and ionoregulatory abilities were examined in the intertidal grapsid crab, Gaetice depressus, transferred from normal seawater (30 ppt) to low (10 ppt) or...     

Astaxanthin profiles and corresponding colour properties in Australian farmed black tiger prawn (Penaeus monodon) during frozen storage

The colour of commercial cooked black tiger prawns (Penaeus monodon) is a key quality requirement to ensure product is not rejected in wholesale markets. The colour, due to the carotenoid astaxanthin, can be impacted by frozen storage, but changes in colour or astaxanthin profile, during frozen storage, have not been studied in detail. Subsequently in this study, the aims were to define the astaxanthin (as cis, trans, mono‐ester and di‐ester forms) content, together with the colour properties, in both pleopods (legs) and abdominal segments. Changes in astaxanthin content and colour properties were further determined during frozen storage (?20°C). Total astaxanthin content was seen to decrease in all samples over time, with the rate of degradation being significantly greater (P < 0.05) in pleopods than abdomen. In both pleopods and abdomen, rate of degradation of esterified forms was significantly greater (P < 0.05) than non‐esterified forms. Hue angle (increase), a* value (decrease) and L value (increase) were all seen to significantly change (P < 0.05) during storage, with changes being more prevalent in the pleopods. The pleopods are the key indicator of astaxanthin and colour loss in cooked black tiger prawns and preservation strategies are required to preserve astaxanthin and colour during frozen storage.     

Effect of vitamin C and astaxanthin on stress and disease resistance of postlarval tiger shrimp, Penaeus monodon (Fabricius)

Postlarvae of tiger shrimp, Penaeus monodon (Fabricius), were fed semipurified diets supplemented with various levels of astaxanthin (AX) and ascorbic acid-polyphosphate (ApP): three groups were fed 230 mg AX kg^?1 diet combined with 100, 1700 and 3400 mg ascorbic acid (AA) kg^?1 diet, respectively; two diets contained 810 mg AX kg^?1 mixed with 200 and 1700 mg AA kg^?1, respectively. Each treatment was run in four replicates. Incorporated levels of AA and AX, production output, and physiological condition were recorded after 4 weeks of feeding. Whole-body AA (21-47 μg g^?1) and AX, concentrations (19-35 μgg^?1) were linked to dietary ApP and AX supply, respectively, although not significantly for the latter. The biomass of the group receiving the lower dietary ApP-AX combination was significantly lower than for all other treatments, i.e. 3.1 versus 3.9 g, respectively. In the groups fed 230 mg AX kg^?1 diet, significant differences in stress resistance were observed according to the dietary ApP level, i.e. raising the vitamin C content in the feed from 100 to 3400 mg AA kg^?1 resulted in a concomitant drop in mortality after an osmotic shock. For the treatments receiving 810 mg AX kg^?1 diet, the beneficial effect of extra dietary vitamin C was not significant. An increase in the dietary AX for shrimp fed comparable ApP levels resulted in a significant drop of the stress index from 56 to 33 (cumulative mortality index). An increased resistance to salinity shock was demonstrated in association with supplementation of high dietary AA or AX levels. No conclusive results regarding possible improved disease resistance could be made since no mortality was observed after a disease challenge with Vibrio harveyi.     

Effects of carbohydrate supplementation on water quality,microbial dynamics and growth performance of giant tiger prawn (Penaeus monodon)

Biofloc technology based 45-day indoor growth trial was conducted to evaluate the effect of carbohydrate (CHO), molasses supplementation on two developmental stages viz, juvenile (J) and sub-adult (SA) of Penaeus monodon in zero-water exchange system. P. monodon juveniles (1.56 ± 0.04 g) and sub-adults (14.32 ± 0.22 g) were stocked in fibre-reinforced plastic tanks (1,000 L) with soil base. Carbohydrate supplementation significantly reduced (p < 0.05) the total ammonia nitrogen (TAN), nitrite-N (NO₂-N) and nitrate-N (NO₃-N) over the time periods in sub-adult group. However, no significant difference in TAN and NO₂-N was observed in juvenile-based treatments. Supplementation of carbohydrate significantly increased (p < 0.05) the water and soil total heterotrophic bacterial (THB) count in both juvenile and sub-adults. Despite increase in total Vibrio count (TVC), lower TVC/THB % was noticed in the water column of J + CHO (0.82) and SA + CHO (0.73) compared to control groups, J ? CHO (1.48) and SA ? CHO (1.21). Supplementation of carbohydrate increased the final body weight in J + CHO (6.51 ± 0.44 g) and SA + CHO (22.52 ± 0.98 g) compared with respective controls, J ? CHO (5.05 ± 0.45 g) and SA ? CHO (20.00 ± 0.33 g). Similarly, significantly lower (p < 0.05) feed conversion ratio and better protein efficiency ratio were recorded in carbohydrate-supplemented juvenile and sub-adults treatment groups. The present study demonstrates that supplementation of carbohydrate reduced the nitrogenous metabolites and significantly enhanced the growth performance of juvenile and sub-adult of P. monodon.     

Hollow sperm syndrome during spermatogenesis in the giant tiger shrimp Penaeus monodon (Fabricius 1798) from eastern Australia

During spermatogenesis, giant tiger shrimp (Penaeus monodon) from Queensland, eastern Australia had a high proportion of testicular spermatids that appeared ‘hollow’ because their nuclei were not visible with the haematoxylin and eosin stain. When examined by transmission electron microscopy, the nuclei of hollow spermatids contained highly decondensed chromatin, with large areas missing fibrillar chromatin. Together with hollow spermatids, testicular pale enlarged (PE) spermatids with weakly staining and marginated chromatin were observed. Degenerate‐eosinophilic‐clumped (DEC) spermatids that appeared as aggregated clumps were also present in testes tubules. Among 171 sub‐adult and adult P. monodon examined from several origins, 43% displayed evidence of hollow spermatids in the testes, 33% displayed PE spermatids and 15% displayed DEC spermatids. These abnormal sperm were also found at lower prevalence in the vas deferens and spermatophore. We propose ‘Hollow Sperm Syndrome (HSS)’ to describe this abnormal sperm condition as these morphological aberrations have yet to be described in penaeid shrimp. No specific cause of HSS was confirmed by examining either tank or pond cultured shrimp exposed to various stocking densities, temperatures, salinities, dietary and seasonal factors. Compared with wild broodstock, HSS occurred at higher prevalence and severity among sub‐adults originating from farms, research ponds and tanks. Further studies are required to establish what physiological, hormonal or metabolic processes may cause HSS and whether it compromises the fertility of male P. monodon.     

The effectiveness of a commercial microbial product in poorly prepared tiger shrimp, Penaeus monodon (Fabricius), ponds

The efficacy of a commercial microbial product was tested in commercial tiger shrimp, Penaeus monodon (Fabricius), ponds for one culture period in Kuala Selangor, Malaysia. Four ponds with replicates for treatment and control were used. The pond bottom was dried but the organic sludge was not removed as normally practised in pond preparation. The ponds were stocked with 15 post‐larvae at the rate of 31.m^?2. Physical, chemical and biological parameters of the pond were analysed every 2 weeks during the culture period. Water quality parameters remained within the optimum range for shrimp culture except for ammonia‐nitrogen being significantly higher in control ponds and silica in treated ponds. Benthic organisms were not found in any of the ponds. The average counts of different bacteria were not significantly higher in treated ponds than control. Because of poor health, the shrimp were harvested earlier (72 days) than the usual 120 days. An average of 875.60 ± 67.00 kg shrimp ha^?1 was obtained in treated ponds with a feed conversion ratio (FCR) of 1.57 ± 0.10 and survival rate of 42.35 ± 5.37% compared with 719.50 ± 130.94 kg shrimp ha^?1, 2.99 ± 0.70 and 21.25 ± 3.26%, respectively, in control ponds. Neither the microbial product nor the frequent water exchange was effective in overcoming the problems caused by the poor pond bottom.     

Light and electron microscopic evidence of white spot disease in the giant tiger shrimp, Penaeus monodon (Fabricius), and the kuruma shrimp, Penaeus japonicus (Bate), cultured in Taiwan

Since 1992, mass mortalities among cultured giant tiger shrimp, Penaeus monodon (Fabricius), and kuruma shrimp, Penaeus japonicus (Bate), have been observed in Taiwan. The condition is known as 'white spot disease' (WSD), based on the characteristic white spots on the cuticle of diseased shrimp. With the scanning electron microscope, two sizes of white spots were observed. Each spot represented a protrusion on the inside surface of the carapace. The composition of white spots was similar to that of the cuticule, most calcium, as determined with an energy dispersive spectrometer. Histological studies of moribund, infected specimens revealed degenerated cells, characterized by hypertrophied nuclei, in various meso- and ectodermal tissues. Infected tissues included cuticular epidermis, connective tissue, lymphoid organ, antennal gland, and haematopoietic, gill and nervous tissue. Nuclei were Feulgen-positive and no occlusion body was found in the necrotic tissue. Transmission electron microscopy revealed the presence of rod-shaped and enveloped virions in the hypertrophied nuclei. The virions measured 298 ± 21 × 107 ± 8 nm in the giant tiger shrimp and 248 ± 12 × 104 ± 8 nm in the kuruma shrimp. In an experimental infection trial, cumulative mortality was 40% within 14 days under stress conditions. No mortality was observed in controls or in non-stressed infected shrimp. Experimental infections show that environmental stressors such as ammonia may enhance the severity of WSD virus infections in cultured shrimp.