Shrimp Penaeus Stylirostris Research Articles

Toxicity and Residue Studies of Cultured Blue Shrimp Treated with the Algicide Cutrine-Plus

Abstract Laboratory bioassays on the blue shrimp (Penaeus stylirostris) were conducted with Cutrine-Plus, a chelated copper algicide registered for use in fish hatcheries but not for shrimp culture facilities. The 24- and 96-h LC50's for blue shrimp were found to be 151.3 and 19.5 mg/L copper as Cutrine-Plus, respectively. Cutrine-Plus was found to be safe (i.e., produced no statistical mortality) at a use rate of 1.0 mg/L for a 24-h static exposure. The 24-h EC50 for gill melanization was 0.64 mg/L copper. In residue studies no accumulation of copper in whole-body tissue due to the treatments could be shown.

Histopathology of aflatoxicosis in the marine shrimp Penaeus stylirostris and P. vannamei

The acute and subacute toxicity of aflatoxin B 1 to the marine shrimp Penaeus stylirostris and P. vannamei (Order: Decapoda, Class: Crustacea) was investigated. Experimental shrimp were exposed to a range of concentrations of the toxin directly by intramascular injection (from 2 to 160 μg aflatoxin B 1/g body weight), or by multiple per os dosing with the feed (from 53 to 300 μg aflatoxin B 1/g feed) for up to 25 days. The histopathogenesis of aflatoxicosis in the aflatoxin-exposed animals was followed and found to be time and dose dependent in the hepatopancreas, mandibular organ, and in the hematopoietic organs. Less significant and/or inconsistent lesions were also observed in other organs and tissues, but a time-dose dependency was not noted. The principal lesions of aflatoxicosis in penaeid shrimp occur in the hepatopancreas and the mandibular organ. In the former organ, subacute and acute aflatoxicosis is expressed as necrosis of the hepatopancreatic tubule epithelium that proceeds from the proximal (older) portion of the tubules, in the center of the organ, to the peripheral (younger) tubule tips. A marked intertubular hemocytic inflammation followed by encapsulation and fibrosis of affected tubules follows in subacute aflatoxicosis, but is not as developed as in acute aflatoxicosis. The mandibular organ in aflatoxicosis displays a necrosis of the peripheral epithelial cells of the cords within the gland that progresses proximally to the central vein. Only a slight hemocytic inflammation accompanies the degenerative changes in this latter organ.

Absence of formaldehyde residues in penaeid shrimp exposed to formalin

Cultured blue shrimp ( Penaeus stylirostris) were treated with normal therapeutic amounts of formalin (50 and 150 ppm) for 6 or 24 h. Analyses for extractable formaldehyde residues were run on the tails from these shrimp immediately after death and after storage at ambient (24°C) and refrigerated temperatures. No formaldehyde residues in these shrimp were found to result from the therapeutic use of formalin. However, shrimp tail muscle was found to produce small amounts (up to 4.8 ppm) of extractable formaldehyde during postmortem decomposition.

STAGGERED STOCKING OF Penaeus stylirostris IN BRACKISH‐WATER PONDS RECEIVING POWER PLANT COOLING WATER

ABSTRACTBlue shrimp (Penaeus stylirostris) were cultured in 11 0.1‐ha earthen ponds during the spring and summer of 1979 to compare conventional and staggered stocking techniques. Three batches of post‐larval shrimp (stocks I, II and III) were stocked at intervals of about 3.5 weeks. Seven thousand eight hundred stock I shrimp were introduced into each of 3 ponds, 7,800 stock II shrimp into each of 3 more ponds, and 2,435 stock III shrimp into each of 2 more ponds. Two additional ponds received approximately equal increments of the 3 batches to reach final stocking densities of 7,635. The final pond received only the first 2 increments for a final stocking density of 5,200.Survival and yield ranges were 18.4–63.2% and 3.3–45.0 kg/0.1 ha, respectively. Ponds that received 3 stocking increments had mean survival rates and yields (36.8%, 32.3 kg/0.1 ha) higher than expected values (32.2%, 22.5 kg/0.1 ha) calculated using the mean values from the single‐stocked control ponds.Salinities were near 2 ppt (range, 1–6 ppt) for most of the 53‐ to 106‐day culture period. This may have depressed shrimp growth.

STATUS, POTENTIALS AND PROBLEMS OF MARICULTURE IN COSTA RICA

ABSTRACTDespite the existence of important fishery resources and a considerable potential for aquaculture the present annual fish consumption in Costa Rica amounts to about 4 kg per capita, which represents only about 2% of the total consumed protein. Due to a low rating of aquatic organisms among the food preferences Costa Rica has in the past shown only a relatively little interest in mariculture.However, a favorable political climate, limited legal restrictions, production incentives, an existing basic infrastructure, and suitable sites for mariculture, especially for the farming of the blue and white shrimp (Penaeus stylirostris and P. vannamei) and of the freshwater prawn (Macrobrachium rosenbergii), have in the last years attracted the interest of private companies for investment in mariculture, and for the production of luxury food for exportation, mainly to the United States.The intensive use of fertilizers and pesticides in agriculture endangers many of the existing and potential sites for aquaculture. The lack of trained manpower, willing to do practical work in mariculture enterprises, adds to the difficulties for expanding and intensifying mariculture in Costa Rica.

ASSORBIC ACID: NUTRITIONAL REQUIREMENT AND ROLE IN WOUND REPAIR IN PENAEID SHRIMP

ABSTRACTAscorbic acid (AsA) has been identified as a dietary requirement for cultured juvenile penaeid shrimp (Penaeus californiensis and Penaeus stylirostris). A dietary intake of 0.1% was sufficient to prevent nutrition‐related deaths among these shrimp. Without sufficient dietary AsA, a deficiency death, Black Death, occurred. This disease is characterized by melanized hemocytic lesions distributed throughout the collagenous tissues of the shrimp' body. The specific requirement for AsA was demonstrated by feeding a special AsA supplement which resulted in the cessation of Black Death among an AsA‐deficient population. Normal collagen metabolism and wound repair in two penaeid shrimp (Penaeus californiensis and Penaeus stylirostris) was shown to be dependent upon ascorbic acid (AsA) nutrition. A significantly greater number of mortalities occurred among wounded AsA‐deficient shrimp of both species due to poor wound repair than among wounded controls.

DEPLETION/REPLETION OF ASCORBIC ACID IN TWO SPECIES OF PENAEID: Penaeus californiensis AND Penaeus stylirostris

AbstractDepletion/repletion of ascorbic acid in whole body tissue was studied in 2 populations of shrimp (Penaeus californiensis and Penaeus stylirostris) using potentiometric titration. Biological half‐life (T1/2) for ascorbic acid (AsA) in P. californiensis and P. stylirostris was 12.5 days and 4 days, respectively. Depletion values for both species were in the range of 0.03 to 0.04 mg AsA g whole body tissue, while the repletion rate, given feed containing 9 and 14 g AsA/kg feed, was 0.01 mg AsA/g tissue per day. A supersaturation or “flush” phenomenon (0.06 mg AsA/g tissue per day and 0.04 mg AsA/g tissue per dayl followed by a swift depletion was observed when the shrimp were fed high doses of ascorbic acid (90 and 141 g AsA/kg feed for P. californiensis and P. stylirostris, respectively). Swift repletion of ascorbic acid tissue levels (0.08 mg AsA/g tissue per day) was also observed in P. stylirostris with access to algae.The shrimp were maintained in flow‐through fiberglass aquaria containing no primary productivity or in a controlled environment aquacell which supported a flora of predominantly Enteromorpha sp.

SUSPECTED BLUE‐GREEN ALGAL POISONING IN THE BLUE SHRIMP

AbstractBlooms of a marine blue‐green alga, Spirulina subsalsa, were found to cause a particular disease syndrome, called hemocytic enteritis, in tank or raceway‐reared blue shrimp (Penaeus stylirostris). The disease was characterized by necrosis of the lining epithelium of the midgut and occasionally of the dorsal caecum and hindgut gland. Bacterial infections, due predominantly to Vibrio alginolyticus, were common in affected shrimp and were presumed to be a secondary condition resulting from necrosis of the gut epithelium. Intestinal lesions were induced in blue shrimp fed living cultures of S. subsalsa sp. as a diet supplement, but not in shrimp fed fresh cultures of other algal forms (Oscillatoria sp. and Nitzchia sp.) indigenous to the shrimp culture tank and raceways. Blue shrimp reared in tanks in which S. subsalsa was the dominant algal form showed reduced growth rates, reduced biomass, and reduced survival compared to shrimp reared in tanks in which Enteromorpha sp. and various diatom species were dominant.Recent findings indicate that blooms of certain Oscillatoria sp. and possibly other blue‐green species may also produce the syndrome in tank or raceway‐reared blue shrimp.

Microbial Flora of Pond-Reared Shrimp (Penaeus stylirostris, Penaeus vannamei, and Penaeus setiferus)

Aerobic plate counts of fresh pond-reared shrimp (Penaeus stylirostris, Penaeus vannamei, and Penaeus setiferus) ranged from 1.5 × 103 to 1.3 × 104 per gram. Coryneform bacteria and Vibrio spp. dominated the microbial flora of shrimp. Aerobic plate counts of pond waters ranged from 6.1 × 102 to 2.2 × 104 per milliliter. Vibrio spp. usually were dominant in pond waters. Enterococci and coliform levels in shrimp were low. Fecal coliforms were present in only one of 11 shrimp samples. No Escherichia coli was recovered from pond-reared shrimp. Salmonella, Vibrio parahaemolyticus, Bacillus cereus, and Clostridium perfringens were not recovered from either shrimp or pond waters. No relationship could be established between changes in numbers and types of microorganisms in pond-reared shrimp or pond waters and changes in characteristics of the pond waters such as temperature, salinity, dissolved oxygen, and pH.