Private Fish Farm Research Articles

EFFECT OF DIETARY METHIONINE ON GROWTH AND UTILIZATION OF CLARIAS GARIEPENIUS FINGERLINGS

The growth response and feed utilization of Clarias gariepinus fed with diet containing different level of dietary synthetic methionine was investigated to determine the effect of diet on their growth rate and its utilization by fish. (108) fingerlings of Calrias gariepinus (2.1+0.5g) obtained from a private fish farm in Benin City were stocked in eighteen (18) 25L plastic tank. 6 diet (40%) crude protein consisting of a control (0% methionine supplementation) and five DIT other diet (3.2%, 4.23%, 7.30%, 8.70% and 9.79% synthetic methionine supplementation) were compounded and fed to the fish till satiation. Each diet was fed to the fish twice daily (9.00hrs and 17.00hrs). Data on the weight gain and feed consumed were taken on weekly basis. There was no significant difference in term of relative weight gain (RWG), specific growth rate (SGR), total weight gain (TWG) and weekly weight gain (WWG). The control with (0% methionine) showed a higher weight gain with diet 5 (8.76% methionine) having a lower weight gain. However, the feed intake (FI) was significantly different (P<0.005) with the control midway the highest feed intake but diet 2 (4.25%) with a step downward showed lowest feed intake. The protein efficiency ratio (per) value were significantly different with diet 1 having the highest value which was different from all other which with diet 4 having a lowest per. In terms of survival there was significant difference (P<0.05) with diet 3(0% methionine). Supplementation has the highest and a reduced survival at diet 2 synthetic methionine. In this study synthetic methionine had not been sufficiently utilized by Clarias gariepinus fingerling since the control did perform better than those supplemented with various level of methionine.

Some Physiological and Biochemical Studies on Marine Fishes Rearing in Suez Canal Fish Farms

The present work was done to elucidate the impact of water quality in private fish farm in Suez Canal area and agricultural drainage water supply source (sectors A and B), Samples of three different fish species: seabream (Sparus aurata), Seabass (Dicentrarchus labrax), and Meagre (Argyrosomus regius) (sectors C, D and E), on the fish physiology, blood picture, biochemistry and accumulation of heavy metals in flesh and gills of the reared fishes. It was found that, water temperature in the different fish farm sectors around the year were significantly different, however, the pH was slightly basic. In spite of the water dissolved oxygen was around the suitable limits, its minimum value was recorded in the fish farm sector (C). Nonetheless, in this fish farm the maximum levels of salinity and total dissolved salts were recorded. Similarly, the ammonia, nitrite and nitrate concentrations were revealed in this fish farm. The relative dominance of heavy metals in the pond's water of the three investigated fish farm sectors all over the period of the study was Fe, Cu, Pb and Cd. However, heavy metals are highly accumulated in fish flesh of all fish farm sectors than in its water column. The muscle content of the detected heavy metals which accumulate in all examined fish species muscle and gills not exceeded the permitted value suggested by FAO/WHO. Metal pollution index realized its minimum levels in water and fish tissue. It is obvious that, the levels of all heavy metals detected in water samples and S. aurata, D. labrax and A. regius muscle tissues (the edible portion of fish) were under the notified permissible limits. Some of the measured parameters slightly exceeded the permissible limits recommended by regulatory agencies

Catastrophic mass mortalities caused by Photobacterium damselae affecting farmed marine fish from Deeba Triangle, Egypt

Farmed marine fish constitute 20% of the total farmed fish production in Egypt, and the Deeba Triangle produces a relatively large portion of this percentage. Last year, several private fish farms in the Deeba Triangle have suffered severe economic losses due to acute fish mass kills. This study aimed to investigate the hidden aetiologies behind these colossal mass fish kills and to propose an emergency control strategy. Several tons of dead farmed fish were remarkably scattered throughout affected ponds and at the vicinity of impacted fish farms. Moribund farmed European seabass (Dicentrarchus labrax), thin-lipped grey mullet (Liza ramada) and gilthead seabream (Sparus aurata) have exhibited skin darkness, emaciation, congested gills and fins, ascites, skin erosions and ulcerations. Internally, moribund fish emitted unpleasant odour upon opening the abdomen together with severe congestion and haemorrhages in kidneys and brain. Mottled atrophied spleens were the most prominent findings, while the gastrointestinal tracts were filled with whitish caseous material. The liver was pale with multiple whitish nodules. Photobacterium damselae was the most retrievable bacterial pathogen from most infected fish and trash fish. Photobacterium damselae subspecies piscicida and Photobacterium damselae subspecies damselae were definitively identified from examined moribund fish using both conventional morpho-chemical and molecular assays. Data analysis has revealed that the poor water quality was profoundly incriminated in triggering the bacterial infections with a fate of mass mortalities. Conclusively, adopting various strict biosecurity strategies will be the key factors in prevention of future episodes of mass kills.

Heavy metals bioaccumulation in marine cultured fish and its probabilistic health hazard.

In aquacultures, heavy metals could be accumulated in fish tissues from natural and human-related sources depending on different factors. This study aims to estimate the level of bioaccumulation of heavy metals in cultured Gilt-head sea bream Sparusaurata. In this regard, heavy metals concentrations were measured in both water and fish musculature that were collected from a private fish farm in Kafr ElSheikh, Egypt. Regarding the water samples, heavy metals were within the permissible limits with exception of Cd, Cu, and Zn. In fish musculature, all heavy metals were within the WHO/FAO permissible limits. The bioaccumulation factor (BAF) indicated that mostly all heavy metals accumulation in the Gilt-head sea bream musculature decreased with time which may be correlated with the increase in water pH, calcium, and other cations concentrations. The hazard index (HI) calculations indicate no adverse health effects of heavy metals on humans through daily fish consumption so far. However, health risks are not negligible making the regular monitoring of metal contaminants in the studied area a necessity.

Ultrastructural morphology of the Myxobolus dermatobius Ishii 1915 (Mixosporea: Myxobolideae) microspores infecting eyes of Nile tilapia (Oreochromis niloticus) in Egypt.

A total of 1,000 cultured Nile tilapia (Oreochromis niloticus) were collected from different governmental and private fish farms and examined for detection of myxosporean parasites infection. The infected fishes showed slight unilateral exophthalmia with whitish cyst in the eye. Numerous white cysts like plasmodia of Myxobolus dermatobius were recovered from the eye of the examined fishes with low prevalence rate (1%). Small intact cyst was isolated, fixed in 3% glutaraldehyde in 0.1 M sodium cacodylate (pH 7.4) and prepared for transmission electron microscopy examination. Ultrathin sections myxospores of M. dermatobius revealed pair of capsulogenic cells at the apical pole of the developing myxospore. Single sporoplasm containing a single nucleus and sporoplasmosomes fills nearly all the space beneath the polar capsules. The later were pyriform in shape, each one had homogenous dense core and 4 turns of polar filaments. Ultrastructural characteristics of the present myxospore were described and discussed in detail.

Modern features of aquaculture of cyprinids in the republic of Iraq

It is shown that the leading role in the aquaculture of Iraq belongs to Cyprinids, which account for over 80 % of all fish farming production. The most widespread in the country are four main world species of carp aquaculture: common carp (Cyprinus carpio), grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis). Basically, the traditional technology of growing Cyprinids in ponds is used, which includes the main fish farming processes: care of broodstock to prepare them for spawning, collecting eggs and milt, eggs fertilization and incubation of embryos, raising juveniles and marketable fish. Currently, there are about 2 thousand private fish farms, which have ponds of various sizes from 4 to 100 hectares. Cultivation of Cyprinids in Iraq is carried out mainly by extensive methods: the use of the natural food base of reservoirs with low fish stocking density in polyculture. The fish productivity of ponds varies greatly in different fish farms from 1,5 to 6 t/ha, which is due to economic reasons. The data on changes in the temperature of pond water during the year and hydrochemical indicators are given, which shows favorable conditions for Cyprinids rearing. Information on the use of compound feeds for growing carp in ponds is provided, and data on the composition and nutritional value of the feed used. The fish culture indicators for the main biotechnical processes of the rearing of four Cyprinid species in Iraq are described in detail. In the conclusion, it is indicated that for the effective development of aquaculture in Iraq, government support is needed in the form of a developed long-term program and legislative acts.

Emerging MDR-Pseudomonas aeruginosa in fish commonly harbor oprL and toxA virulence genes and blaTEM, blaCTX-M, and tetA antibiotic-resistance genes

This study aimed to investigate the prevalence, antibiogram of Pseudomonasaeruginosa (P.aeruginosa), and the distribution of virulence genes (oprL,exoS, phzM, and toxA) and the antibiotic-resistance genes (blaTEM, tetA, and blaCTX-M). A total of 285 fish (165 Oreochromisniloticus and 120 Clariasgariepinus) were collected randomly from private fish farms in Ismailia Governorate, Egypt. The collected specimens were examined bacteriologically. P. aeruginosa was isolated from 90 examined fish (31.57%), and the liver was the most prominent infected organ. The antibiogram of the isolated strains was determined using a disc diffusion method, where the tested strains exhibited multi-drug resistance (MDR) to amoxicillin, cefotaxime, tetracycline, and gentamicin. The PCR results revealed that all the examined strains harbored (oprL and toxA) virulence genes, while only 22.2% were positive for the phzM gene. On the contrary, none of the tested strains were positive for the exoS gene. Concerning the distribution of the antibiotic resistance genes, the examined strains harbored blaTEM, blaCTX-M, and tetA genes with a total prevalence of 83.3%, 77.7%, and 75.6%, respectively. Experimentally infected fish with P.aeruginosa displayed high mortalities in direct proportion to the encoded virulence genes and showed similar signs of septicemia found in the naturally infected one. In conclusion, P.aeruginosa is a major pathogen of O.niloticus and C.gariepinus.oprL and toxA genes are the most predominant virulence genes associated with P.aeruginosa infection. The blaCTX-M,blaTEM, and tetA genes are the main antibiotic-resistance genes that induce resistance patterns to cefotaxime, amoxicillin, and tetracycline, highlighting MDR P.aeruginosa strains of potential public health concern.

Stocking density, Survival rate and Growth performance feed utilization and economic evaluation of Litopenaeus vannamei (Boon, 1931) in different cultured shrimp farms in Suez Canal Region

Two studies were conducted to evaluate growth performance, feed utilization, survival and the economic production of white shrimp (P. vannamei) in Suez Canal region. The first study was conducted in Eldebba farm in western region of Port Said Governorate collaboration with a private fish farm. The second study was conducted in Suez Canal Fish Farm with an area of 1feddans. The pond was stocked with white shrimp (P. vannamei) at the rate of 70000 P26 /feddan in eldebba Port-Saied Governorate. In Suez Canal ponds stocked with 150000 P26/ feddan white shrimp (P. vannamei) with average initial 0.002g . A good quality (38% protein) commercial feed was provided. Growth performance, feed utilization , survival and comical evaluation was the best in Eldebba farm than Suez Canal farm. It could be concluded that stocking white shrimp at density 70000/feddan was the best in terms of growth performance, feed utilization, survival and economic evaluation under this experimental conditions.

Bioremediation effect of pomegranate peel on subchronic mercury immunotoxicity on African catfish (Clarias gariepinus).

The primary aim of the present study is to evaluate the highest concentrations of heavy metals (HMs) in Nile catfish (Clarias gariepinus, C. gariepinus) and water samples, as well as to investigate the efficiency of pomegranate peels (PPs) (supplemented either through water or diet) in enhancing fish immunity and counteracting the toxicity of high concentrations of HMs. Water and C. gariepinus samples were collected from two private fish farms in Al Sharkia Governorate. Mercury (Hg) showed the highest concentration (0.13 ppm). The adsorption capacity of PP was evaluated by testing different concentrations, 0.3, 0.6, 0.9, 1.2, and 1.5 g L-1, wherein 1.5 g L-1 revealed the highest Hg adsorption efficiency. The results indicated that Hg concentration was decreased with increased PP concentration until 72 h. In a trial that lasted for 60 days, 240 C. gariepinus (75.12 ± 3.12 g) were randomly divided into eight equal groups with three replicates per group. The first group (CT) served as the negative control (fish fed on a basal diet). The second group (PPW) was fed on a basal diet and supplemented with 0.3 g L-1 of PP via water. The third (PPD1) and fourth (PPD2) groups received basal diets enriched with 1 and 2 g PP powder/kg diet. respectively. The fifth group (Hg) served as the positive control that was fed on a basal diet and exposed to 0.13 ppm of Hg. The sixth (Hg + PPW), seventh (Hg + PPD1), and eighth (Hg + PPD2) groups were exposed to 0.13 ppm of Hg and received the same type of treatment as in second, third, and fourth groups. Hg exposure significantly elevated aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, and creatinine levels, as well as oxidative stress biomarkers, including reduced glutathione (GSH) and malondialdehyde (MDA). Pomegranate supplementation through diet elevated the levels of red blood cells (RBCs), hemoglobin (Hb), packed cell volume (PCV), lysozyme, and anti-protease activity. Moreover, PP supplementation through water revealed minimum urea and creatinine levels, and the highest nitric oxide level. Moreover, Hg residue level in fish muscles noticeably decreased in the PP-treated groups. These results demonstrated the efficiency of PP supplementation (either through water or diet) in enhancing fish immunity and counteracting subchronic Hg toxicity.

Pathological, bacteriological and seasonal prevalence of Aeromonas hydrophila, vibrio vulnificus, Proteus vulgaris and Pseudomonas aeruginosa; infecting Oreochromis niloticus in some Egyptian fish farms

In this study, ninety fish samples showing clinical signs of septicemia were collected from two private fish farms of Oreochromis niloticus; forty fish were sampled from fayoum and fifty were from sharkia governorate, Egypt, during four seasons (autumn 2018 to summer 2019). The sampled diseased fish represented 10% of the fish, showing clinical signs and the mortality rate along the year was 15 %. In the postmortem examination, the signs of septicemia on the affected fishes were clear in most of the internal organs. The histopathological results were fully described in different organs of the affected fish. Bacteriological examination revealed isolation of Aeromonas hydrophila with prevalence rate along the year 77.33 % with the highest prevalence in summer (100%) in El Fayoum and it was 29.72 % along the year with the highest prevalence in autumn 33.33% in El Sharkia governorate. Vibrio vulnificans in El Fayoum governorate was not isolated but it was isolated from El Sharkia with prevalence rate of 16.22%; with the highest prevalence in autumn (33.33%,). Proteus vulgaris was identified in both governorates with overall prevalence rate of 6.67% in El Fayoum and the highest prevalence was recorded in both autumn and spring seasons (11.11%). In El Sharkia it was 27.03% but with the highest prevalence in summer (100%). Pseudomonas aeruginosa was also recorded with the prevalence rate of 20% along the year in El Fayoum governorate with the highest prevalence in winter 55.56% and it was 27.03% in El Sharkia governorate with the highest prevalence in winter 43.75%. In antibiotic sensitivity testing, each microorganism showed resistance against erythromycin except Vibrio vulnificus that showed sensitivity. Aeromonas hydrophila and Proteus vulgaris showed resistance to colistin sulphate and susceptibility to sulpha-trimethoprime. Vibrio vulnificus and Pseudomonas aeruginosa showed resistance against sulpha-trimethoprime and sensitive against colistin sulphate.

The Effect of some Dietary Medicinal Herbal Extracts on Growth Performance and Economic Efficiency of Nile Tilapia

This experiment was performed to study the effect of ginger and licorice extracts on to the diets on growth performance, feed utilization and economic efficiency besides water and fish quality. The experiment started at 15 May to 15 September 2019 for a period of 120 days at a private fish farm in Fayoum Governorate, Egypt. 1680 monosex Nile tilapia (Oreochromis niloticus) fingerlings with an average weight of 18.26 g ± 0.34 have been randomly distributed in 12 net hapa in six experimental groups (4×7×1.5 m with a water volume of 28 m3 and 140 fingerlings) suspended in an earthen pond. The diets was (T1) control group, fed on the basal diet only; T2 and T3 the basal diet sprayed with aqueous ginger extract at a rate of 2 and 4 ml/kg feed; T4 and T5 the basal diet sprayed with aqueous licorice extract at a rate of 2 and 4 ml/kg feed and T6 mix group, fed on the basal diet sprayed with 2 ml ginger plus 2 ml licorice aqueous extracts/kg feed. The results showed that ginger and licorice extract supplements were able to minimize heavy metal accumulation in the body of the fish (levels of cadmium, lead and copper) Special to expand adding. While 4 ml of licorice or ginger was better than 2 ml and combining extract better than both. Fish fed mixed diet (T6) achieved the best significant final body weight followed by dietary fish groups (T5), (T4), (T3) and (T2), respectively, Whereas control group (T1) obtained the lowest values. The best FCR and higher levels of feed intake (FI), protein efficiency ratio and PPV were obtained when fish were fed on T6 diet. Which the best significant values in all parameters. T6 showed significantly higher net yields and economic efficiency compared with other tested diets. While control diets T1 had the least economic output significantly (P≤0.05).

Evaluation of some Essential and Toxic Metals in farmed Ctenopharyngodonidella in relation to Body Size and Condition Factor

Basic aim of this research was to determine levels of some metals (Ca, Cd, Cr, Co, Cu, Fe, K, Mn, Ni, Na, Pb Zn) and their relationships to body size and condition factor in the whole body of Ctenopharyngodon idella (Grass carp). Concentrations of these elements were assessed in 55 fish samples of different size, randomly collected in January, 2015, from a private fish farm by ICP-OES after wet digestion method. Results of the study showed that analyzed elements were found within normal ranges. Ca, Cu, Fe, K, Mn, Na and Zn had highly significant relationships with fish size. Cd, Pb, Cu, K, Mn, Ni, Na, increased isometrically while Cr, Co, Zn, had negative allometric relationship and Fe and Ca showed positive allometric relationship with rise in weight of C. idella. Moreover, Ni, Mn, Pb and Cd represented isometric increase whereas Na, K, Zn, Fe and Ca had positive allometry; and Co, Cu, Cr had negative allometry with increase in total length of the fish. Most of inter-elemental relationships showed. Multiple regressions analyses showed positive correlation for Fe, Cu, Zn, Mn, Pb, Na, K, Ca and Ni had highly significant relations with total length and body weight.

Impact of Aluminum Phosphide on the Transferases in Liver and muscle of Parophiocephalus obscurus

This study assessed the effect of aluminum phosphide on transferases in liver and muscle of Parophiocephalus obscurus (with mean weight of 42.20±1.5 gSD and mean length of 16.50± cmSD, respectively). The fish were obtained from a private fish farm in Yenagoa Metropolis, Nigeria, and the fish was allowed acclimatized to laboratory condition for 7 days, and then exposed to sublethal concentrations (0.00mg/L, 4.20mg/L, 6.30mg/L and 8.40mg/L) of aluminum phosphide for 14 days. Renewal bioassay was adopted in this study. At the end of the experimental period, the fish was dissected and the muscle and liver were collected, processed and analyzed for alanine aminotransferase and aspartate aminotransferase using colorimetric method. Results of the phosphatase at 0.00mg/L, 4.20mg/L, 6.30mg/L and 8.40mg/L were 94.50±6.44µ/L, 134.47±15.27 µ/L, 106.47±9.21 µ/L and 31.00±3.46 µ/L, respectively (liver), 107.50±9.24, 92.00±6.93 µ/L, 116.50±8.95 µ/L and 146.33±9.33 µ/L respectively (muscle) for aspartate aminotransferase; and 40.00±1.15µ/L, 26.50±3.18µ/L, 14.50±2.02µ/L and 9.80±1.44 µ/L, respectively (liver) and 17.00±1.75µ/L, 8.50±0.87µ/L, 21.00±2.89µ/L and 5.50±0.87 µ/L, respectively (muscle) for alanine aminotransferase. Statistically, there were significant variations (p<0.05) among the various concentration in the transferances. In addition, at some concentration, there was significant variations (p<0.05) between the level of the transferases in the muscle and liver. The significant alteration observed in the various concentrations is an indication that aluminum phosphide is lethal to fish. Therefore, caution should be exercise during the use of aluminum phosphide near biological system.

High mortalities caused by Aeromonas veronii:identification, pathogenicity, and histopathologicalstudies in Oreochromis niloticus

The current study planned to identify suspected causes of mass mortalities in Oreochromis niloticus at private fish farms in Port Said Governorate, Egypt, during the 2017 summer season. One hundred twenty diseased moribund O. niloticus fish were randomly collected from different locations. The examined fish showed lethargy, dark skin, bilateral exophthalmia with corneal opacity, and varying degrees of ulcers. Internal examination revealed generalized inflammation, congestion, hemorrhaging, and enlargement of most internal organs. Identification was accomplished through analytical profile index (API) 20E and polymerase chain reaction (PCR) and confirmed by sequencing and phylogenetic analysis. An antibiogram was constructed based on results from a disc diffusion test. Experimental infection was also performed and showed 80% mortality. Virulence genes were also assayed. Histopathological examination of experimentally challenged fish revealed prominent pathological lesions (mainly necrosis), degenerative changes, and cellular vacuolation. In conclusion, Aeromonas veronii can be considered one of the main causes of summer mass mortalities in O. niloticus in the study area.

Molecular Characterization of Vibrio Harveyi and Vibrio alginolyticus with the Impact of Stressful Environment on Some Naturally Infected Marine Fish

Cultured seabass (Dicentrarchus labrax L.) and seabream (Sparus aurata L.) are marine species of high economic important especially in Mediterranean aquaculture. Among bacterial diseases of marine cultured and wild fish, vibriosis caused by Vibrio species is one of the most prevalent diseases. In the present work, we report the isolation and identification of the V. harveyi and V. alginolyticus, based on biochemical and molecular characterization, from cultured seabass and seabream native to private fish farms at Mathalath-El Diba region, Domitte City at Domitte Governorate, Egypt during summer season. The most prominent clinical signs of diseased fish were hemorrhagic ulceration on the dorsal musculature and caudal peduncle area as well as sever protrusion of the eye outside the orbital cavity. Histological examination of seabass revealed haemorrhage on the liver and nodular formation on different organs especially in kidney and liver. While, diseased seabream showed marbling appearance of gill with nodular formation and necrotic area distributed over the liver. Physico-chemical characteristics of water samples collected parallel to fish samples indicated that pH and organic matter of the water sample was within the permissible limits. However, the unionized ammonia, nitrate, and hydrogen sulphate concentrations were higher than the acceptable limits. Moreover, the heavy metals (copper, zinc, cadmium, lead, mercury, nickel, and iron) contained of water samples were higher than permissible limits. In regards to the haematological parameters associated with diseased and apparently healthy seabream and seabass. The total protein, albumin, and globulin were lower in diseased seabass and seabream than apparently healthy fish. Serum lysozyme and bactericidal activity was lower in the diseased fish than apparently healthy seabass and seabream. Levels of aspartate amino-transferase (S.AST) and alanine amino transferase (S.ALT) in plasma of diseased seabass and seabream were higher than apparent healthy seabass and seabream. Altogether, higher level of heavy metal concentrations in water samples than the permissible limits act as chemical stressors that help in increase the prevalence of V. harveyi and V. alginolyticus species in seabass and seabream.

Parasites of Nile tilapia (<i>Oreochromisniloticus</i>) from selected fish farms and Lake Koftuin central Ethiopia

This study was conducted from October 2016 to January 2017 at Lake Koftu, Sebeta ponds and selected private fish farms in Wonchi area, Ethiopia. The main objective was to identify the major parasites of Oreochromis niloticus to the lowest possible Taxa, thereby determine the prevalence, mean intensities and mean abundances of parasites. A total of 302 O. niloticus (101 from Lake Koftu, 127 from Sebeta pond and 72 from selected small scale fish farms) were collected and examined for the presence of parasites.The overall prevalence of all parasites in Lake Koftu, Sebeta ponds and private fish farms were found to be 100%, 71.0% and 82.2% respectively. There was statistically significant difference (p<0.05) between the study sites in overall prevalence. Nine Taxa of parasites were identified in Lake Koftu, the Trematode Tylodelpyes spp. being the most prevalent parasite (93.1%). In Sebeta fish ponds, 11 Taxa of parasites were recovered from O. niloticus with the most prevalent parasite being Trichodina (37.5%) and four Taxa of parasites from small scale fish farms were identified and the highest prevalent parasite being with Trichodina spp (53.25%). The study showed that fingerlings from Lake Koftu had high prevalence of parasitic infestation and hence may be source of parasites for others when used for stocking small scale fish farms requiring intervention measures such as deworming before being stocked to other farms.Keywords: Ethiopia; Fish farms; Lake Koftu; Oreochromis niloticus; Parasites, Prevalence

SEASONAL VARIATION OF GILL, SKIN, MUSCLE, LIVER AND KIDNEY PATHOLOGY OF MRIGAL (Cirrhinus cirrhosus) IN CULTURAL POND FISHERIES, MYMENSINGH, BANGLADESH

An investigation on the seasonal variation of gill, skin muscle, liver and kidney pathology of Mrigal (Cirrhinus cirrhosus) was carried out from four Government (Govt.) and four Private (Pvt.) fish farms, Mymensingh, Bangladesh during June, 2010 to May, 2012. Fish sampling and water quality parameters were monitored monthly basis. For histopathological studies skin, muscle, gill, liver and kidney were collected, processed and stained in Haematoxylin and Eosin. Histologically, Mrigal of different fish farms were more affected in colder months. All the investigated organs of Mrigal were exhibited few abnormalities during summer, however, mild hyperplasia, haemorrhage, partial loss of secondary gill lamellae, marked and hypertrophy was observed during the rainy season. Several pathological changes like necrosis, fungal granuloma, protozoan and monogenean cyst, vacuolation, melanomacrophase, haemorrhage, hypertrophy, hyperplasia and clubbing were recorded in all the investigated organs. Among them fish gills and skin were more affected followed by liver and kidney. In some cases, large bacterial colony and protozoan cyst were observed in the secondary gill lamellae of Mrigal. The ectoparasites were very common in gills and skin of all fishes. Water quality parameters were taken and management practices were investigated fortnightly interval in different farms. These were almost similar for all experimental ponds. The risk of being infestation by parasites of carp significantly (p<0.001) increased when the water quality parameters such as temperature, dissolved oxygen, pH, ammonia, hardness, alkalinity, transparency and depth of water etc. were not maintained the optimum level.

Studies on Parasitic Crustaceans among Some Cultured Marine Fishes in Ismailia Governorate

The present study was conducted on a total of 200 marine fishes (100 of Dicentrarchus labrax and 100 of D.punctatus) collected from different private fish farms in Ismailia Governorate. There were no pathognomonic lesions in the naturally infested fishes except marbling appearance of gills infested by Isopoda. Skin lesions were found in opercular cavities of fishes infested by Isopoda. The main P.M lesions were hemorrhagic areas on EBS and emaciation. Some fishes showed Sea lice in the buccal cavity with ulcerative lesions in the area of attachment. The highest crustacean infestation rate was recorded in Dicentrarchus labrax (75%) followed by D.punctatus (42%). The isolated crustacean parasites from both fish species were copepods (Lernanthropus kroyeri, Caligus minimus and C.longipedis) and Isopods (Nerocila spp., Renocila spp. and Anilocra spp.).Total and Seasonal prevalence of crustacean parasites, histopathological picture and identification of copepod parasites using molecular biology (PCR) were also recorded.

Assessment of zinc and lead concentration in water and muscles of Labeo rohita collected from wild and local fish farms of Pakistan

Reasonable evidences suggest that heavy metal pollutants have been added by factories and other industries to our local water bodies. The present study was conducted to determine the heavy metal (zinc and lead) concentrations in muscle tissues of Labeo rohita inhabiting local water bodies as well as those being raised at farms. Sampling was performed to collect Labeo rohita from two different stations along river Ravi, viz. Lahore Siphon (upstream) and Balloki Headworks (downstream). Additionally, samples were also obtained from the government operated as well as private fish farms located in Lahore District, Pakistan. The fish were dissected; their muscles were digested, filtered, and finally analyzed for concentrations of Zn and Pb. Significant variation of heavy metal ions were observed between two sites along river Ravi as well as government operated and private fish farms. Significantly high mean concentrations of Zn (10.7±1.268) and Pb (0.61±0.082) were observed at Balloki Head-works; whereas, the lowest Zn (1.58±0.235) and Pb (0.16±0.008) heavy metal levels were recorded in the muscle samples collected from private fish farms. It was also observed that the heavy metal concentration in the muscles of Labeo rohita, collected from Balloki Head-works was much higher than the permissible limits laid down by WHO/FAO. Further the recorded highest level of heavy metals in water samples collected from River Ravi indicates that the bioaccumulation of heavy metals is severely affecting the aquatic life of fresh water and industries should not be allowed to release their effluent directly into the river Ravi in their vicinity.

Occurrence of functional single-lobed ovary in Cirrhinus mrigala (Hamilton,1822) brood fish from Assam, India

Occurrence of abnormally developed gonads in fish is rather more uncommon in freshwater fish than marine fish. It is therefore worthwhile to disseminate the information of occurrence of a single-lobed ovary in Cirrhinus mrigala brood fish as an abnormal phenomenon. During April 2011 to March 2013, around 500 brood fish samples of Indian major carps (Labeo rohita, Catla and C. mrigala) were collected from different government and private fish farms of Assam and Tripura located in the Northeast of India. Among them, one C. mrigala specimen measuring 41 cm in total length and 640 g in weight collected from Ulubari fish seed farm of Guwahati, Assam during June, 2012 was found to have a single-lobed ovary instead of the normal bilobed structure. The ovary occupied the entire body cavity and the majority of ova were round and translucent. The ovary contributed substantially to the total body weight with gonado-somatic index of 32.81 which was the highest among all the mrigal specimens examined. The study indicates possibility of artificially inducing development of single-lobed ovary in C. mrigala for achieving possible higher spawn outputs in induced breeding of the cultivable species.