1999, 23(3).
Abstract:Ultrastructure of compound eye was investigated by TEM and SEM in the larval stages of Penaeus chinensis .The result indicated :The compound eye is in photoreceptive rudiment at Z1 stage .During Z2 stage , the main components of every ommatidium of compound eye were completed .The surface of ommatidium had the appearance of hexagonal facetting before post-larval stage .But the facet was square when the length is 0 .7 ~ 0 .8cm at post-larval stage .Some main organelles of corneagenous cell , such as mitochondia , rough endoplasmic reticulum, etc .decreased gradually .Crystalline tract secreted by crystalline cells began at Z2 stage and became thick gradually .Iris pigmental cells didn' t produce pigmental granules before the post-larval stage .Retina pigments slight increased gradually as developing .The rhabdom was formed at Z2 stage and lengthened gradually .
1999, 23(3).
Abstract:The morphology and structure of thelycum and sperm storage in Penaeus chinensis and Trachypenaeus curvirostris were studied using laser scanning confocal microscope .They all have closed thelycum.The thelycum of T .Curvirostris is covered with fore-and-aft two carapace slices , between the slices in center aperture , which is usually stoppered by jelly substance after male .At the center of thelycum is one single cavity and there are two sack-like vesicle at rear end of thelycum in which sperm sacs are stored .The thelycum of P .chinensis has single cavity covered with two semi-round , right-left symmetry carapace slices .There are three tapers shaped prominences stick out from front into the cavity .In maled female Chinese shrimp , the prominences were mosaicked into spermatophore , which could firm the spermatophore .
1999, 23(3).
Abstract:The effects of mandibular organ (MO)in ovarian development were studied using implantation method .A pair of MO were implanted into the abdominal muscle of crayfish at an interval of 5 days .MO implantation for 7 times caused increase of gonadosomatic index(GSI)and promoted the enlargement of oocyte diameter .The effects of mandibular organ extracts (MOE)at different developmental stage of ovaries in crayfish were also studied in vitro .It was found that MOE at vitellogenesis stage had highly significant effect on enlarging oocyte diameter at primary and secondary vitellogenesis stages , but had no effect on enlarging oocyte diameter at pre-vitellogenesis stage .MOE at early ovarian developing stage had no effect on total RNA enhancement of ovarian fragment at vitellogenesis stage .MOE at pre-vitellogenesis , vitellogenesis and redeveloping stages had highly significant enhancement on total RNA of ovarian fragment at vitellogenesis stage .The effect of MOE is similar to juvenile hormone analogue -ZR515 .The results indicate that the ovary during the vitellogenesis is more sensitive to MOE ;the biological effect of MOE at vitellogenesis stage is biggest .The function material of MO has promotive effect on oocyte development .
1999, 23(3).
Abstract:Using the sandwich enzyme-linked immunosorbent assay(ELISA)for grass carp growth hormone , plasma kinetics of rcGH in Clarias batrachus after administrations of rcGH were investigated .After intramuscular injections of rcGH (0 .2 and l μg g)into C .batrachus , the plasma rcGH levels were increased , peak values were seen at the end of 2 and 3 hours post-injection , and rcGH in plasma was undetected on the 2nd and 4th days post-injection , respectively .Similar uptake and clearance patterns were seen after intraperitoneal injections rcGH(0 .2 and l μg g)into C .batrachus . Intraperitoneal injections of rcGH (0 .5 , 1 and 2 μg g)to walking catfish , rcGH in plasma was all undetected on the 7th day post-injection .When rcGH(0 .2 and 0 .5 μg g)was injected into intracaudal vessel of C .batrachus , plasma rcGH levels decreased by way of exponential decay , rcGH in plasma was detectable 24h postintra-caudal vessel injection .
1999, 23(3).
Abstract:To produce tripoids , fertilized eggs of Chlamys(Azumapecten)farreri were treated with 6 -dimethylaminopurine (6 -DMAP)to inhibit the extrusion of the second polar body .Using dihydrochloride (DAPI ) stain and fluorescence microscopic observation , the relation between chromosome karyotype and triploid induction and larval survival percentage , the effects of egg maturation and spawning temperature on the synchronous development of fertilized eggs were analyzed . It was concluded that the optimism induction parameters for farming industry are as following : completely mature eggs , initial treatment time when the first polar body occupied 40 %, 60mg L of drug concentration , 15 min of treatment duration and water temperature kept at 20 ℃ from spawning to the end of treatment .Under the conditions , triploids can be obtained with an induction rate higher than 80 % and an hatching rate up to 70 %.
1999, 23(3).
Abstract:By the secretory action analysis of hypophysis gonadotropic hormone ( GTH ) cell of long snout catfish ( Leiocassis longirostris ) captured in the estuary of Changjiang River, it was verif ied that combinative injection of LRH - A 50ugPkg and DOM 50mgPkg could stimulate the secretion of GTH, induce the maturation and ovulation of oocyte. The results also indicate that there are two kinds of secretory granules in the GTH cell, one granule is bigger with diameter about 1 200- 2 000nm and lower electron-density ; the other one is smaller with diameter about 300- 500nm and higher electron-density. The release of bigger granule ( secretory gloube) was relative to development and maturation of oocyte while the release of smaller granule ( secretory granule ) was relative to ovulation.
1999, 23(3).
Abstract:Genetic population structures of Protosalanx chinensis , Neosalanx taihuensis , and N .oligodontis in Lake Taihu were assayed using RAPD method .P .chinenesis and N .taihuensis were collected in six regions throughout the whole lake , and N .oligodontis was collected in two of the six regions.Results demonstrated that these three Salangid fishes did not reveal any structural differentiation .Genetic similarity indices suggested that P .chinensis has to lost genetic variation a greater degree because in history it suffered a greater loss in population quantity than N .taihuensis and N .oligodontis resulted from fishing pressure , while N .taihuensis and N .oligodontis have maintained somewhat larger genetic variation .
1999, 23(3).
Abstract:Common and different morphological aspects , discriminant methods of Nile tilapia (Oreochromis niloticus), blue tilapia(O .aureus)and their hybrid (O .niloticus ♀×O .aureus ♂) were reported .Morphological differences of hybrid and their parents were comprehensively analyzed by χ2 -test of 8 meristic characters , and by clustering analysis , discriminant analysis and PCA of 9metric plus 24 truss network characters .The hybrid resembled blue tilapia from body color , but it resembled Nile tilapia from the results of three multivariate analysis in body shape by different combination of genes.Genetics of body color and body size were controlled by different combination of genes . Discriminant functions were formed to identify Nile tilapia , blue tilapia and their hybrid .
1999, 23(3).
Abstract:Diurnal dynamics of DOC and POC in two shrimp ponds were studied. It was shown that: DOC concentration decreased from 14: 00 to 18: 00, increased from 18: 00 to 22: 00, then decreased again, and ranged from 3. 22 mgPL ( Pond 1) to 1. 24 mgPL ( Pond 2) ; while POC concentration increased gradually in daytime( 6: 00- 18: 00) and decreased gradually at night( 18: 00- next 6: 00) , and ranged from 1. 28 mgPL( Pond 1) to 1. 26 mgPL( Pond 2) . The pond with a high POC concentration was also with a high DOC concentration. The rates of DOCPPOC decreased gradually in daytime( 6: 00- 18: 00) , increased gradually at night( 18: 00- next 6: 00) , and peaked at 2: 00( Pond 1) and 6: 00( Pond 2) . The diurnal ratios of DOCPPOC averaged 1. 6P1. 0( Pond 1) and 1. 9P1. 0( Pond 2) . CPN ratios of suspending organic particulated matters were the biggest at 18: 00 and decreased gradually at night( 18: 00- next 6: 00) .
1999, 23(3).
Abstract:One of strains were isolated from the liver of diseased soft-shelled turtle of furunculosis , red neck and red spot complicating diseases , which was proved to be the pathogen of the disease by the challenge test .The isolate was tested for more than 30 unit morpholohic , physiological and biochemistric characteristics , and classified as Aeromonas hydrophila .It was short straight rods (0 .36 ~ 0 .71μm×1 .0 ~ 1 .4μm), Gram negative ,single polar flagellum, neither capsule , nor spores but motible .ONPG test , arginine dihydrolase , indole production , Voges-proskauer reaction , gelatinase , oxidase and esculin were positive .Acid production from glucose ,mannitol , sucrose and Darabinose .Lysine decarboxylase , ornithine decarboxylase , utilization of sodium citrate , H2S production , urease and indolylpyruvic acid(IPA)were negative .The LD50 of the isolatod bacteria on Crucian carp is 9 .17 ×105CFU, and the LD50 on mice is 1 .59 ×107CFU .Optimum growth temperature , pH and salinity ranges from 25 ℃ to 35 ℃, 6 .5 to 7 .5 , and 5 to 15 sodium chloride , respectively . This isolate was highly sensitive to Ciprofloxacin , Ofloxacin , Amikacin , Chloramphenicol , Doxycycline , Tetracycline , Kanamycin , Aztreonam , Netilmicin , Cefuroxime , Piperacillin , Cefotaxime , Ceftriaxone and Ceftazidime , etc .
1999, 23(3).
Abstract:Juvenile Penaeus japonicus were experimentally infected by feeding minced shrimp tissue of WSSV-infected .The experimental shrimps were sampled everyday and whole body of the shrimp was cryosectioned then WSSV was detected by FAT method using monoclonal antibodies in order to explain the virus development in shrimp body .The results indicated that in the first three days post-infection the virus was not detected in any samples ;on the forth day the virus was first detected in hemacyte in gill cavity ;on the fifth day it developed to gill tissue , epidermal tissue and hemal sinus ; on the sixth day to stomach and heart ;on the seventh day to lymphoid organ and mid-gut ;on the eighth and ninth days to all the detected tissues but not to the hepatopancreas .
1999, 23(3).
Abstract:Minced meat from herring was defatted , then extruded by a twin-screw extruder together with soybean protein isolate .This operation was carried out at a feed rate of 33kg h , a screw speed of 120r min and a barrel temperature of 160 ℃.The results indicated that the defatted fish meat with fat contents of 2.8 % and 1.6 %(dry base)respectively showed better texturization properties .The extrudates appear a sponge structure , and have the chewiness properties of meat .The results of scanning electron micrograph show that the fine structure of extrudates consists of a well-aligned fibrous structure , and the fibers parallel to the entrusion direction .