Histopathological changes in gill, kidney and liver of an estuarine mullet, Liza parsia, induced by sublethal exposure to DDT

Liza parsia were exposed to sublethal (0.02 ppm) concentration of DDT for 15 days. The gill responded initially with copious secretion of mucus, oedematous separation of epithelial cells from the basement membrane and fusion of secondary gill lamellae. Hyperplasia of the cells lining primary gill lamellae and lamellar telangiectases (or aneurysms) was frequently seen after day 10 of exposure. Kidney exhibited hypertrophy of the epithelial cells lining proximal convoluted tubules which was followed by shrinkage in glomerular tufts, increase in Bowman's space, appearance of amorphous eosinophilic materials in the lumina of the tubules and focal necrosis on day 10 of the treatment. Hyaline droplets and casts were also encountered in the epithelial cells and lumina of the proximal tubules. Liver revealed an initial dilation of canaliculi and increased secretion of bile. Thereafter, the displacement of nuclei towards periphery of the hepatocytes, disorganization of blood sinusoids, pyknotic changes in nuclei, cytolysis and vacuolation as well as focal necrosis were noticed after day 10 of the intoxication.

Observation on the production performance of Penaeus monodon with Liza parsia under different cropping system

Study was conducted in six ponds each with an area of 0.1 ha in the pond complex of Brackishwater Station, Paikgacha, Khulna from February to October '96, to find out the variation of production rate in two culture system viz., single and double crop of P. monodon with L. parsia. In treatment T1 wild fry of P. monodon (0.006g) and L. parsia (0.20g) collected from nearby river were stocked at a rate of 40,000 and 10,000/ha, respectively, for a culture period of 120 days. In treatment T2, the rate was 20,000/ha for bagda fry in 1st and 2nd crop each and 10,000 for parsia fry/ha for an extended period of 225 days. The highest survivability and growth of P. monodon and L. parsia were 57.08% (1st crop of T2) and 75.26% (T2), and 27.08g (1st crop of T2) and 47.78g (T2), respectively with a significant variations (P>0.05) with other treatment. The net profit (Tk. 93,134) and cost benefit ratio of 1:1.76 were also found higher in T2.

Preliminary success on hormone induced captive breeding of goldspot mullet, Liza parsia (Ham.)

An attempt was made to breed goldspot mullet, Liza parsia in captivity through hormone induction. The fish started spawning 35-36 hours after a single dose of 2ml ova prim per kg body weight. Hatching of fertilized eggs completed within 42-48 hours after spawning. The mean hatching rate (%) was 71.33±12 corresponding to the fertilization rate (%) of 64±12. The larvae started its first external feeding on the third day and attained a length 2.5±0.25 mm. The salinity of both breeding and rearing cisterns was 20‰ and temperature was maintained at 22-23°C.

Studies on the effect of steriod hormones on the gronth and biochemical composition of the mullet liza.parsia (hamilton)

The present study has helped in finding out an efficient growth promoting substance for the fry of Liza garsia. 1Zfimethyltestosterone at the dosages of 2 mg/kg diet is the most effective anabolic agent for Liza parsia. The study also shows that by incorporating 8 mg MT/kg of diet the protein level in the diet could be reduced from 35 to 30%. thereby a significant saving in the cost of feed could be obtained. Further, the anabolic effect of MT helps to reduce the rearing period during the production of fingerlings from the fry stage.

Studies on the digestive enzymes of the cultivable grey mullet liza parsia (hamilton buchanan, 1822)

Culturing of fish in captivity demands a detailed knowledge on well balanced diet and adequate feeding. Formulation and production of nutritionally balanced diets for fish require research, quality control and biological evaluation. It is often assuemed that what is ingested is also digested, but this is not always be the case. Digestion depends upon both the physical state of the food and the kind and quantity of enzymes in the digestive tract. The ability of fish to digest a particular component of diet can be ascertained by investigating the complement of digestive enzymes present along the digestive tract. Investigations on the basic digestive physiology will not only enhance our present knowledge on nutrition and feed development, but will also contribute in understanding the digestive functions of lower vertebrates. It is against this background that the present topic of investigation "Studies on the digestive enzymes of the cultivable grey mullet Liza parsia Hamilton Buchanan, l822" has been selected. The thesis is arranged and presented in eight chapters.

Nutritional Requirements Of The Fry Of Gold-Spot Mullet Liza Parsa (Hamilton)

Most tropical aquatic environments are naturally fertile and their natural fertility is renewed very rapidly. Natural food for many cultivable organisms can be grown to the maximum by proper management. However, enrichment of the environment can be done through rational fertilization. Still further increase in stocking rates, can yield increased crop if adequate feeding is done. Thus fish and shellfish nutrition is an important aspect of the multidisciplinary subject of aquaculture. The oldest and most classical studies in physiology have investigated the nutritional needs of the species of interest to aquaculture. The alimentary requirements for proteins, lipids, mineral salts and vitamins have been established for some temperate species. But, the nutritional requirements of only few tropical species have been studied. Before formulating a diet, a thorough knowledge of the nutrient requirement of the species is essential. It is against this background that the present area of investigation has been identified. "Nutritional requirements of the fry of gold-spot mullet Liza parsia" is a comprehensive attempt to quantify the nutritional factors that are essential for producing healthy fingerlings for stocking the farms. Aspects such as the protein and lipid requirements of the fry, the vitamin essentiality, nutritive evaluation of protein and lipid sources suitable for compounding diets were covered in this research project. The ultimate aim has been to evolve practical diets which could be applied in the nursery phase for juvenile production.

Effect of farm made feeds on polyculture of shrimp (Penaeus monodon) and three brackishwater finfish species

A study was conducted to evaluate the effects of feed made from locally available ingredients on polyculture of shrimp and three brackishwater finfish species. Hatchery produced post-larvae (PL) of shrimp Penaeus monodon (0.005g) were stocked at the rate of 15,000 PLs/ha. Brackishwater finfish species Liza parsia, Mugil cephalus and Rhinomugil corsula of 0.63-1.4lg collected from local rivers were stocked at the rate 8,000, 1,000 and 2,000/ha, respectively in four treatments. Shrimp and finfishes were fed four different experimental diets composed of fish meal, mustard oil cake, rice bran, oyster shell power and vitamin premixes at the rate of 3-5% estimated crop/day for 195 days. Among four treatments, P. monodon showed comparative better growth in T4 and T3. Finfish L. parsia showed its better performance in treatment T2. Species M. cephalus and R. corsula showed insignificant production. P. monodon showed better growth with diet of fish meal and mustard oil cake@ 28.84 and 33.65%, respectively in T 3 and 19.22 and 43.27%, respectively in treatment T4.

Smoking of shrimp and fish from coastal village of north-west Bangladesh

Traditional smoking of mixed shrimp species is a method of preservation in coastal region of Bangladesh. Besides traditional smoked shrimp, attempt had been made to produce smoked shrimp from brown shrimp, Metapenaeus monoceros and fish from mugil, Liza parsia and the quality of smoked product was found good very on the basis of physical properties, proximate composition and mineral contents of the products.

Studies on amylolytic bacteria in Cochin backwaters

This thesis Entitled Studies on amylolytic bacteria in cochin backwaters.This thesis presents a detailed account of the disribution of amylolytic bacteria in water. sediment. fishes ( Etroplus suratensis and Liza parsia) • prawns ( Penaeus indicus and Metapenaeus dobsoni) and clams ( Sunetta scripta and Meretrix casta) from Cochin backwaters. genera-wise distribution of amylolytic bacteria, ability of selected strains to grow and produce amylase at various physico-chemical conditions. Regulation of amylase synthesis anrt characters of amylases producer by these halophilic bacteria.Amylolytic bacteria are distributed widely in water. sediment. fishes. prawns and clams of Cochin back waters. 53% of the total isolates tested were capable of producing amylase. Maximum number of arnylolytic bacteria were present in Metapenaeus dobsoni. In general, the gut region of aquatic animals harboured more amylolytic bacteria than the gill or surface. These bacteria may help in the digestion of starch present in their food.Presence of ions in the medium was found to be essential for growth and amylase production. It was found that this ionic requirement is not highly specific. Sorlium chloride could be replaced by potassium chloride. or magnesium chloride to some extent I without affecting growth and amylase production. The important function of these ions may be to maintain the osmotic balance between the cells and their environment.All the isolates showed the ability to grow and produce amylase using raw-starches from cassava. plantain and potato .This property suggests their role in the rdegradation of native starches in the environment

Digestão nitro-sulfúrica de fígado de peixe Mugil liza em forno de micro-ondas com radiação focalizada para determinar elementos de interesse ambiental por ICPMS

O presente estudo propõe uma metodologia para dissolução de tecidos biológicos em sistema de micro-ondas com radiação focalizada e posterior análise elementar por espectrometria de massas com plasma acoplado indutivamente (ICPMS). Foram determinados os elementos arsênio (As), cádmio (Cd), cobre (Cu), chumbo (Pb), níquel (Ni), vanádio (V) e zinco (Zn). A matriz nitro-peroxo-sulfúrica foi comparada com outra sem o ácido sulfúrico e apresentou melhor padrão de recuperação (acima de 90%) na quantificação dos elementos certificados no material de referência TORT-2. As interferências causadas pela presença do ácido sulfúrico na matriz digestora foram contornadas com o uso da célula de reação/colisão com gás hélio (He) e adição deste ácido na composição da curva de quantificação. O ganho analítico proporcionado pelo método de digestão em matriz sulfúrica, em sistema não pressurizado, baseia-se no incremento da temperatura reacional e na degradação completa da matéria orgânica. As digestões tradicionalmente realizadas para quantificação por ICPMS, compostas unicamente de ácido nítrico (HNO3) e peróxido de hidrogênio (H2O2), não apresentam a mesma eficiência na degradação da matéria orgânica em sistemas abertos. Por fim, este método foi aplicado satisfatoriamente em amostras de tecido hepático de peixe Mugil liza (tainha), comprovando sua eficiência em monitorar a bioacumulação, utilizando-se da sensibilidade da técnica multielementar de ICPMS

Study on biological characteristics, sexual maturation and reproduction of Liza abu in the water of Khozestan Province

As the most of the fish resources are known and exploited, protecting their generation is of the greatest importance. Aquaculture is one of the efficient procedures in protecting and reviving fish resources and knowing about the reproductive cycle and gonads development has an important role in approaching this aim. Liza abu belongs to the family Mugilidae that according to its resistance to the environmental condition and its fast growth , can be introduced as a fish with economical value. As there is no scientific data on the reproductive biology of this species , study on the reproductive biology and gonad development is considered as the aim of this research . For this purpose , 360 samples of this species were investigated during the period from February 2007 to January 2008 in Khozestan Province . After studing morphological and histological characteristics of gonad specimen , they were prepared through histological method. Samples were prepared through usual histological method and studied under light microscope. According to the results, the maturity stages of male and female Liza abu were separated to six different successive stages. In ovaries , these stages were as follow : In stage І, the oocytes were small , this stage was observed from July to October . In stage ІІ, considerable growth was observed in the oocytes . This stage was observed from October to January . In stage III, due to vitellogenesis, the maximum growth was observed and three layers of theca, granullosa and follicle cells were visible. This stage was observed during January and February . In stage IV, migration of germinal vesicle was observed and due to hydration of the oocytes , their diameter was increased. The ovaries were yellowish and in maximum size and ovules could be easily observed with naked-eye . This stage was observed in February and March . In stage V, spawning occured. This stage was observed in April . In stage VI, ovaries consisted of immature and atretic oocytes and also empty follicles. This stage was observed in May and June. In testes , these stages were as follow : In stage I , the testes were small in size and contained the spermatogonia which were the only cellular components.This stage was observed in August and September . In stage II (maturing virgin ) , the spermatogonia and the primary spermatocytes were visible. This stage was observed in October . In stage III (developing), intensive spermatogenesis was occured and the primary and the secondary spermatocytes were the most visible cells during this stage .This stage was observed from November to January. In stage IV(developed), cells of all stages of spermatogenesis could be seen but the secondary spermatocytes and spermatids were in large number. This stage was observed from January to March. In stage V , the testes were filled with sperms. This stage was observed in March and April .In stage VI, residual spermatozoa and the spermatogonia were visible in the testes. This stage was observed from May to August. According to cyclic changes in GSI, sexual maturation in breeding begins in January and spawning occurs in April. The ova diameter ranged from 30.75 μ in stage I to 472.19 μ in stage IV. In this study , the sex ratio was 1:2.7, and male and female percentage were 27.02% and 72.98% respectively. This means that females predominate males. In this study absolute fecundity was calculated and changing between 30805.44 to 431247.3 was observed and absolute fecundity was calculated 111275.3 in average.

Quantative and qualitive identification of the fatty acids in the mullet (Liza aurata), sever juga (Acipenser stellatus) and Persian sturgeon (A. persicus), considering of cold storing effects on them

At the fishing season, in 2000, samples of species persian sturgeon (A. persicus), Severjuga (A. stellatus) and Mullet (L. aurata), were caught from the southern coasts of Caspian Sea and were freezes and preserved in the cold storage for one year They have also become biometery. The tissue's fillet were identified in order to determined the Fatty Acids. This was done during one year, frequently, fresh, two weeks after freezing and then monthly, respectively. So, after the extraction of lipids from the tissues and methylation, was injected to the gas-liquid Chromatography. After calibration, identified Fatty Acids were compared with standards according to their Retention Times. Peroxid value, lipid content and humidity were controlled. The unsaturated Fatty acids had The most amount, and a plenty of Polyunsaturated Fatty acids (PUFA) were observed, so that linoleic (C18:2), a-linolenic (C18:3), Arashidonic (C20:4), EPA (C20:5) and DHA (C22:6) Fatty acids had high amounts. The w-3, PUFA were more in comparison with w-6. The effects of freezing and cold storing on the fish fatty acids , were evaluated by the statistical tests , like SPSS, Tukey, Homogenous and Anova, and showed that in some species, a group of Fatty acids, specially PUFA, had some variation. The peroxide value that indicates the lipid deterioration, increased during toring. So, the best term if preserving in the cold storage, were determined and their Nutrition value and Medical applications due to their consumption were investigated.

Feeding level-scaled retention efficiency, growth and energy partitioning of a marine detritivorous fish, redlip mullet (Liza haematocheila T. & S.)

The effects of feeding level on growth, retention efficiency, faeces production and energy partitioning of redlip mullet were studied. A practical diet was used and fed at six levels from starvation, 1%, 2%, 3%, 4% of body weight (BW) to satiation for 3 weeks. The temperature was kept at 24 +/- 1 degrees C. Reducing the feeding amount resulted in significantly lower weight gain, and retention efficiency was significantly affected by feeding levels and attained the maximum at maximum feeding intake. Feeding 2% BW was the minimum required for fish to maintain growth. Fish carcass composition under different feeding levels could be divided into three groups: (1) starvation and FL1; (2) FL2 and FL3 and (3) FL4 and satiation, with significant differences among the groups but no differences in the groups except that ash content remained at constant value. Body composition of fish of group 2 was close to initial fish. The thermal-unit coefficient was 0.0381 at satiation, and significantly increased with increasing feeding levels. In order to accurately estimate basal metabolism (HeE), another trial on the relationship between HeE (kJ) and BW (g) was carried out. An exponential curve as HeE=0.1255BW(0.8386) explained this relationship. Intake energy (IE) increased from 11.30 to 63.08 kJ per fish, matching with different feeding levels. Energy allocated to growth of IE decreased with reducing feeding amount. There was a linear relationship between metabolism energy and retention energy in percentage.

Transporting nutrients from sediments: nitrogen and carbon as indicators to measure scavenging ability of a detritivorous fish, Liza haematocheila

The redlip mullet, Liza haematocheila, is a common species in polyculture as a scavenger in China. Feeding on detritus, redlip mullet transports nutrients from sediments up into the water column and converts them into forms that can be utilized by phytoplankton and affects the relative abundance of detritus and dissolved inorganic nutrients to phytoplankton, zooplankton and other fishes. We used nitrogen and carbon as the indicators in this study to measure the scavenging ability, which means intake of nitrogen or carbon by redlip mullet, and the loss of nutrients. Temperature and body weight significantly affected growth nitrogen, faecal nitrogen and faecal carbon. At a certain temperature, the proportion of growth nitrogen or growth carbon increased while the proportion of excretion nitrogen or respiration carbon decreased with increasing body weight.