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| ORIGINAL ARTICLE |
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| Year : 2015 | Volume
: 6
| Issue : 1 | Page : 38-43 |
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Histopathological alterations in the vital organs of Indian Major Carps with parasitic infestation in fish farms West Bengal, India
Kurva Raghu Ramudu, Gadadhar Dash
Department of Aquatic Animal Health, West Bengal University of Animal and Fishery Sciences, Kolkata, West Bengal, India
| Date of Web Publication | 8-Jan-2015 |
Correspondence Address:
Kurva Raghu Ramudu
Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, 5, Budherhat Road, Chakgaria, Kolkata - 700 094, West Bengal
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2394-2002.148893
The study was conducted to investigate the histological changes of vital organs such as kidney, gills and brain with the mixed infestation of parasites in Indian Major Carps (IMC). The parasites such as Myxobolus spp., Thelohanellus spp., Trichodina spp., Dactylogyrus spp., Gyrodactylus spp. and Nematodes were observed in three IMC. Several histological alterations were observed in the kidney of Catla catla, Labeo rohita and Cirrhinus mrigala, which includes vacuolar degeneration in the epithelium of renal tubules, focal areas of necrosis, proliferation of bowman's capsule and many cases the renal tubules lost its shape and canalculi formation was observed. The gills showed focal areas of necrosis, exacerbated swelling of gill arch, deposition of distinct black melanin pigmentation at the basal point of the gill arch, loss of primary and secondary lamellae, prominent vacuolar degeneration and formation of vacuoles. The presence of protozoan parasites in brain tissue resulted necrosis of the brain tissue, black pigmentation, vacuolization of myelin sheath of nerve fibers and common degenerative changes. Aims: To study histological changes of vital organs such as kidney, gills and brain with the mixed infestation of parasites in Indian Major Carps (IMC). Settings and Design: The organs fixed in 4% formalin are transferred to 50% ethyl alcohol and stored for further analysis. Materials and Methods: Histopathological analysis was made as described by Roberts. Statistical Analysis Used: Nil. Results: Described in text. Conclusions: The present study brings about conclusion that impact of mixed infestation of the parasites on their hosts was severe. Histopathological changes were observed in vital organs which might be due to toxins released by different parasites or physical damage of tissue with the presence of parasites. Keywords: Histological alterations, Indian major carps, vital organs
How to cite this article:
Ramudu KR, Dash G. Histopathological alterations in the vital organs of Indian Major Carps with parasitic infestation in fish farms West Bengal, India. Drug Dev Ther 2015;6:38-43 |
How to cite this URL:
Ramudu KR, Dash G. Histopathological alterations in the vital organs of Indian Major Carps with parasitic infestation in fish farms West Bengal, India. Drug Dev Ther [serial online] 2015 [cited 2017 May 23];6:38-43. Available from: http://www.ddtjournal.org/text.asp?2015/6/1/38/148893 |
| Introduction | |  |
The Indian major carps, namely Catla catla, Labeo rohita and Cirrhinus mrigala contribute as much as 87% of total fresh water aquaculture production. Parasitic infestations, especially ectoparasites like protozoans, monogenetic and digenetic flukes are the most devastating groups affecting skin and gills that induces sliminess of the skin, irritation, destruction of gills, anorexia and impaired breathing (Lom [1] and Abbas et al. [2] ). The synergistic action of the parasites may cause mortalities (Abbas et al., [2] Osman [3] ) Ectoparasitic ciliates are the most common parasites found in fishes (Lom and Dykova [4] ). Trichodina spp. as well as Chilodonella spp. causes 70% mortality among 2-months old fry of cultured grass carp (Uzbilek and Yilidiz [5] ). Trichodina spp. glides rapidly over the gills and skin, affects all fish species causing direct or indirect death (Durborow). [6] Trichodinids commonly occur in association with other ectoparasites, especially, monogenic and digenic flukes (Pearse). [7] Monogenetic flukes are a group of parasites best described as flatworms commonly found on the gills, skin or fins of fishes have a series of hooks that attach to the fish causing irritation, excessive mucus production (Reed et al.[8] and Soulsby [9] ). Severe infestation of monogenean flukes may cause dyspnea and die of condition of cultivable fishes (Moeller). [10] Digenetic trematodes require several hosts to complete their life cycle. The majority of digenetic trematodes that infect fish by metacercaria larvae or "grub" stage (Bowser). [11] Metacercarial larval infestation in fish causes economic losses to the farmers due to mass mortality (Paperna). [12]
It is important to mention here that the parasitic infestations were reportedly playing a major role in disease occurrences (78%) in Indian freshwater aquaculture (Lakra). [13] Scientist reported that ectoparasitic diseases are the main problem in freshwater fish farms of Andhra Pradesh (Mohan et al.). [14] The freshwater fish farmers of Andhra Pradesh, India (Vineetha and Abraham [15] ) and West Bengal, India (Sil et al.) [16] were estimated to produce about 21% and 26% less, respectively than the expected production due to diseases, poor farm management practices and impaired growth. It is important to mention here that parasitic infestations caused stress at initial stages then followed by mortalities. So it is very important to study parasitic infestations and histological changes in vital organs of parasitized fishes. Histological alterations used as indicators for entire health of overall population in the ecosystem. The objectives of present work was to study the histological changes of vital organs such as kidney, gills and brain due to mixed infestation of parasites in Indian major carps (IMC).
| Materials and Methods | | |
The samples of (Catla catla, Labeo rohita and Cirrhinus mrigala) were collected in live condition and brought to the laboratory with water filled buckets. Vital organs like kidney, gill and brain were thoroughly observed under microscope for the presence of parasites. These organs were infested by different parasites such as Myxobolus spp., Trichodina spp., Thelohanellus spp., Dactylogyrus spp. and Gyrodactylus spp. Vital organs from these naturally infested fishes were taken for histopathological observations.
The vital organs were fixed in 4% formalin, transferred to 50% ethyl alcohol and stored for further analysis. Histopathological analysis was made as described by Roberts. [17] The sections were screened and color microphotographs were taken from the selected slides at different magnifications with the help of binocular phase contrast microscope with in-built digital camera and attached monitor (Motic: Model BA400).
| Results and Discussion | | |
The vital organs were infested by different parasites like Myxobolus spp., Trichodina spp., Thelohanellus spp., Dactylogyrus spp. and Gyrodactylus spp., showed in [Figure 1]a-f. These parasites caused internal damage to the tissues of different organs. All the major organs like kidney, gill, brain and muscle were thoroughly studied under microscope for histopathological changes.  | Figure 1: (a) Cyst of Myxobolus spp. (arrow) present in the gills of Catla catla (b) Cyst of Myxobolus spp. (arrows) present on the caudal fin of Labeo rohita (c) Trichodina sp. present on the skin of Labeo rohita (Wet mount, 20x) (d) Two different Thelohanellus spp. from the gills of IMC, and with clear long polar filament (arrows) (Giemsa stained, 20x) (e) Magnified view of Dactylogyrus sp. present in the gills with clear anchor, (arrow) of IMC (Wet mount, 20x) (f) Gyrodactylus sp. with clear attachment site (arrow) and attached to the body of IMC (Wet mount, 10x)
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Kidney
Kidney is a target organ in many diseases due to the affinity of the organ for circulating particulate antigens. Yu and Wu [18] observed severe lesion of the glomeruli capsules and fat deposits on the kidney tubules of Hypophthalmicthys molitrix.
In the present study the kidney of the Catla catla showed distinct black melanin pigmentation, necrosis of nephric tubules and vacuole formation [Figure 2]a and hind kidney showing enlargement of bowman capsule [Figure 2]b. The necrosis of the renal tubules affects the metabolic activities and promotes metabolic abnormalities in fish (Yokote), [19] which was similar with the present observations.  | Figure 2: (a) The kidney of the Catla catla showing distinct black melanin pigmentation (yellow arrow), necrosis of nephric tubules was also evident (light blue arrow) and vacuole formation (green arrow) at some places (H&E, 40x) (b) The kidney of the Catla catla showing distinct black melanin pigmentation (yellow arrow), prominent vacuole formation (green arrow) in some places and enlargement of bowman capsule (pink arrow) (H&E, 40x) (c) The kidney of Labeo rohita showing the prominent circular vacuolar spaces filled with damaged cells (blue arrow) and necrosis of the kidney tissue (light blue arrow) observed. The nephric tubules showed distinct interstitial spaces (red arrow) (H&E, 100x) (d) The kidney of Labeo rohita showing proliferation of bowman capsule (pink arrow) and many cases the renal tubules lost its shape (yellow arrow), (H&E, 100x) (e) The kidney of Cirrhinus mrigala showing black pigmentation (yellow arrow) and distinct vacuole formation (green arrow) normal structure of renal tubules were lost (H&E, 40x) (f) The kidney of Cirrhinus mrigala showing distinct canalculi within the tissue (red arrow) and in some places few black pigments (yellow arrow) were observed (H&E, 40x)
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The head kidney of Labeo rohita showed the prominent circular vacuolar spaces filled with damaged cells, necrosis of the tissue. The nephric tubules showed distinct interstitial spaces [Figure 2]c. Enzootic nature of myxosporidians in Indian Major Carps causing degenerative and necrotic changes in the kidney tubules have been described by Mishra et al., [20] which was similar with present study. The hind kidney showing proliferation of Bowman's capsule and many a cases the renal tubules were deshaped [Figure 2]d.
The head kidney of Cirrhinus mrigala showed black pigmentation and distinct vacuole formation and normal structure of renal tubules were lost [Figure 2]e. The hind kidney showed distinct canalculi formation within the tissue. Canalculi formation may be due to toxins released by parasites or exposure of kidney to lethal concentrations of the toxins which showed enlargement, vacuolar degeneration, necrosis of cells that corroborated with the works of Gupta and Dalela, [21] Csepai, [22] Konar and Hazards, [23] Bakthavathsalam et al., [24] Duable and Shah, [25] Rashatwar et al.[26] and Perisetti. [27] The vacuolar spaces in top corner being occupied by damaged mass of the cells and the normal shape of renal tubules were not observed [Figure 2]f.{Figure 2}
Gills
Gills of Catla catla showed exacerbated swelling of gill arch with complete loss of primary and secondary lamellae which was similar to the works of Dey et al. [28] The arch swelled maximum at middle point compare to basal and proximal point [Figure 3]a. At high magnification, gill tissue showed the exacerbated swelling of gill arch which was similar to the reports of Ghosh et al.[29] and Sanaullah and Ahmed. [30] Depositions of distinct black melanin pigmentation at the basal point of the gill arch were also observed [Figure 3]b. In the present study mixed infestation of parasites were found in the gills. The gill cells respond to the parasites with abnormal production of mucus, also epithelial hyperplasia was observed.  | Figure 3: (a) Gill of Catla catla showing the exacerbated swelling of gill filament (blue arrow) with complete loss of primary and secondary lamellae. The arch swelled maximum at middle point compare to basal and proximal point (H&E, 40x) (b) High magnification of the gill tissue of Catla catla showing the exacerbated swelling of gill filament (blue arrow), deposition of distinct black melanin pigmentation (yellow arrow) at the basal point of the gill arch is one of the feature of the present slide. (H&E, 100x) (c) The gill of the Labeo rohita showing excessive proliferation of gill arch with massive loss of primary and secondary lamellae (orange arrow), the arch shown granulation and vacuoles (light green arrow) (H&E, 40x) (d) High magnifications the gill of the Labeo rohita showing excessive proliferation of gill arch (black arrow) with complete loss of primary and secondary lamellae, prominent vacuolar degeneration were also observed (H&E, 100x) (e) The gill of the Cirrhinus mrigala showing complete degeneration of gill arch (orange arrow), damage of gill arch to very high degree leading to the formation of vacuoles (blue arrow) (H&E, 40x) (f) The gill of the Cirrhinus mrigala showing degeneration and necrosis of arch (light blue arrow) leading to the formation of vacuum space (yellow arrow) (H&E, 40x)
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The gill of the Labeo rohita showing excessive proliferation of gill arch with massive loss of primary and secondary lamellae and the arch showed granulation and vacuoles. The symmetry of arrangement of primary lamellae has been lost, inter digitations were damaged prominently [Figure 3]c. Due to heavy infestation of parasites the gill structures were totally damaged and the swelling might be due to the presence of toxins released by the parasites or pollutants which supported by works of Ramudu and Dash [31] and Perisetti, [27] respectively. High magnifications of the gill showed excessive proliferation of gill arch with complete loss of primary and secondary lamellae, prominent vacuolar degeneration [Figure 3]d, which were similar with results as found in Catla catla (Dey et al).[28]
The gills of the Cirrhinus mrigala showed complete degeneration of gill arch with excessive proliferation of primary lamellae. Similar abnormalities in the gills were observed in fishes exposed to miscellaneous pesticides (Lowe, [32] Eller, [33] Jauch, [34] Nowak, [35] Rijijohn [36] ), metals (Cerqueira and Fernandes [37] and Martinez et al.[38] ) and organic contaminants (Rosety-Rodriguez et al.[39] and Fanta et al.[40] ). The secondary lamellae were almost lost and damage of gill arch was very high, leading to the formation of vacuoles [Figure 3]e. The gill showed degeneration and necrosis of arch leading to the formation of vacuum space and the primary, secondary lamellae were damaged to great extent. The primary lamellae showed excessive proliferation [Figure 3]f. Cirrhinus mrigala being the bottom dweller was in continuous contact with deterioted pond bottom and gills were the primary organs of inflammation of various toxicants, irritants and other hazardous wastes leading to such proliferative changes. These results corroborated with works of Dykova and Lom, [41] McCraren et al.[42] in Catla catla. The present observations were supported by Hassan, [43] who reported the epithelial lining cells of the secondary lamellae with proliferative changes, including, hyperplasia and hypertrophy. The histopathological changes in events of massive infections by ectoprotozoans Trichodinella epizootica in carp (Lom) [44] and Tripartiella cichlidarum in cichlids (Paperna) [12] cause some erosion of the gill. The present observations were also supported by Paperna and Van, [45] who reported that the parasitism with Chilodonella hexasticha produced severe gill damage in the form of epithelial hyperplasia. Langdon et al.[46] reported that heavy C. hexasticha infestation caused mass mortality among farmed and wild fish.
Brain
The brain of the Catla catla showed presence of protozoan parasites in the tissues leading to necrosis. Black pigmentation, vacuolization of myelin sheath of nerve fibers were some of the common degenerative changes observed in brain tissue [Figure 4]a. At high magnification the brain of the Catla catla showed the presence of distinct protozoan cyst, vacuolization, degeneration and necrosis [Figure 4]b. | Figure 4: (a) The brain of the Catla catla showing presence of protozoan parasites in brain tissue (red arrow), black pigmentation observed (yellow arrow), vacuolization (black arrow) were observed in the brain tissue (H&E, 40x) (b) High magnification the brain of the Catla catla showing the presence of distinct protozoan cyst (red arrow), vacuolization (black arrow) also observed (H&E, 100x) (c) The brain of the Labeo rohita showing damage of nerve fibers with prominent vacuolization (green arrow), rush of blood cells indicating onset of the primary inflammatory response (yellow arrow) (H&E, 40x) (d) The brain of the Labeo rohita showing complete degeneration and necrosis of nerve fibers with the clear vacuolization (green arrow), presence of protozoan cyst was the characteristic of this slide (red arrow) (H&E, 40x) (e) The brain of the Cirrhinus mrigala showing complete degeneration and necrosis of nerve fibers with clear cut vacuolization (red arrow), presence of protozoan parasite (light blue arrow) were observed (H&E, 40x) (f) The brain of the Cirrhinus mrigala showing presence of protozoan cyst (blue arrow), haemocytic infiltration (yellow arrow) as a mark of inflammatory response was noticed (H&E, 40x)
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The brain of the Labeo rohita showed damage of nerve fibres with prominent vacuolization, rush of blood cells indicating the onset of the primary inflammatory response [Figure 4]c. The brain showed complete degeneration, necrosis of nerve fibres' with the clear vacuolization and presence of protozoan cyst [Figure 4]d.
The brain of Cirrhinus mrigala showed complete degeneration and necrosis of nerve fibres with clear vacuolization. Vacuolization in brain tissue might be the result of glycolysis leading to microsomal and mitochondrial dysfunctions. Severe necrosis of neural fibres evident in this work was also supported by the studies of Loganathan et al.[47] Presence of protozoan parasites was another characteristic feature and the brain cells damaged to great extent [Figure 4]e. The brain tissue showed presence of protozoan cyst with rush of blood cells as a mark of inflamatory response and degeneration of nerve cells were quite evident [Figure 4]f. The protozoan parasites penetrate the skin and migrate through subcutaneous tissue and muscle finally enter to the blood vessels to make their way to the brain region. This was similar with the findings of the migration of Diplostomum spathaceum by Ferguson [48] and Posthodiplostomum minimum by Hoffman. [49] A smaller number probably enter the brain directly through the soft parts of the cranium or by route of the cranial nerves.{Figure 4}
| Acknowledgement | | |
Authors are thankful to the Indian Council of Agricultural Research (ICAR), New Delhi for financial support under the Niche Area of Excellence.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
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