An estimation of optimum dietary concentration of soy bean meal for carps (Catla catla, Labeo rohita and Cirhinus mrigala)

Soybean meal is an inexpensive plant origin protein which has been used in practical diets as a replacement of animal protein such as fish meal or chicken meal, due to the uneconomical price of animal protein diets. Consequently, a research study was conducted on some commercial species of Indian major carps i.e. Catla (Cattla cattla), Rohu (Labeo rohita) and Mrigala (Cirhinus mrigala) (Hamilton, 1822) to estimate optimum dietary protein requirement of soy bean meal in diet in an intensive polyculture. Three different diets (SBM I, SBM II and SBM III) were formulated by 80%, 50% and 20% replacement of fish meal with soybean meal from a 45% fish meal diet (control).Highest monthly mean weight gain was obtained by SBM II (with 35% CP and about 50% substitution of fish meal), while SBM III (45% Crude Protein and about 20% substitution of fish meal) was stood second. All tested diets respond enormously by producing high yield as compare to control diet, though SBM II generated highest yield among all. On the bases of the following research, it was revealed that the SBM can surrogate even50% fish meal without any augmentation of other amino acids in the diet of Indian major carps.

Lernaeid parasites prevalence in commercial freshwater fish species at various fish farms in Pakistan

Reports abound on Lernaea parasitizing the brood stock, fingerlings, and marketable-sized culturable freshwater fish species in various parts of the world. We investigated seven small-scale aquaculture farms and how the prevailing Lernaea is impacting them. Randomly seven fish farms were selected to determine the prevalence percentage of lernaeid ectoparasites. Relevant information of the fishponds to estimate the various aspects such as effects of water source and quality, feed, stocking density, treatment used, and weight and length of fish, concerned with Lernaea infestation and prevalence was gathered. The results indicated that Catla catla (F. Hamilton, 1822) showed highest prevalence (41.7%) among the seven fish species, whereas Oreochromis niloticus showed zero. Other five fish species Ctenopharyngodon idella, Cirrhinus cirrhosis, Cyprinus carpio, Labeo rohita and Hypophthalmichthys molitrix showed 13.2%, 8.1%, 7.7%, 7.4%, 0.9% prevalence, respectively. In Royal Fish Farm 84.3% lernaeid infestation was observed, while no parasite was observed in the Vicent’s Chunnian fish farm. The water source, quality, feed, fertilizers, stocking density, water temperature, and potential treatment options displayed varying tendencies among fish farms and prevalence. Depending on the weight and length, the highest prevalence (56.7%, and 66.7%) was observed in 3501-4000 g and 81-90 cm groups. The infestation rate varied in various fish body parts with the dorsal fin the most vulnerable organ and showed 2.3% overall prevalence (while 18.4% contribution within total 12.6% infestation). Out of 147 infected fish samples, 45 were extensively contaminated by Lernaea spread. In conclusion, our findings confirm that Lernaea could pose a considerable threat to marketable fish, and various treatment options should be educated to the farmers to help mitigate the spread and potential losses. Furthermore, Catla catla is more vulnerable to Lernaea infestation (41.7%), so are the fish species being cultured at higher stocking densities.

Occurrence of Infestation with the Isopod, Alitropus Typus M. Edwards (Crustacea: Flabellifera: Aegidae) on Commercially Important Freshwater Fishes of Kerala, India

Rapidly rising temperatures and increasing organic load in the inland and coastal waters has led to a significant increase in parasite population. The isopod Alitropus typus infestation on fish in these waters have become more frequent, causing mortalities in both wild and cultured fishes. The present study was aimed to investigate the infestation on different fish hosts, mean intensity, prevalence, environmental influences on the parasite abundance and the histopathological changes it causes in the host. A total of 219 isopod specimens were collected from 149 infested fishes in two districts of Kerala, India. Among the different fish hosts, Channa striata was found to be the most susceptible, followed by Catla catla, Cyprinus carpio, and Wallago attu, with 81%, 10%, 7%, and 2% occurrence, respectively. The prevalence and mean intensity of infestation were found to be 69.8%, 44.4%, 68.2%, 62.5% and 1.33, 4.25, 1.26, 1.80 in C. striata, W. attu, C. catla, and C. carpio, respectively. The parasite abundance was directly influenced by temperature and rainfall patterns. The histopathology of affected gill tissues showed epithelial lifting, rupture of secondary gill filaments, vacuole formation and hemocytic infiltration. The findings indicated that the isopod parasite, A. typus had a negative impact on fish health and appearance, causing economic losses to the small scale farmers/fishermen. This is the first reported record of the infestation of isopod parasite, A. typus on the Indian major carp C. catla and C. carpio from India.

Induced Breeding of Freshwater Fishes and Cost Benefit Analysis of a Selected Fish Hatchery in Jashore, Bangladesh

An investigation was carried out to know the induced breeding techniques of some firewater fish species such as rui (Labeo rohita), catla (Catla catla), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella), common carp (Cyprinus carpio), bighead carp (Hypophthalmichthys nobilis), sharpunti (Puntius sarana) and bata (Labeo bata) at Ma Fatima Fish Hatchery in Chanchra, Jashore, Bangladesh. The cost-benefit analysis was also performed on this hatchery for three months from May to July, 2016. The brood fishes purchased from different local sources were used for spawning. The hatchery mainly practiced induced breeding by maintaining proper age and weight of brood stock during spawning. The ranges of fertilization and hatching rates of the experimental fishes were 80.04±1.44 % to 94.35±0.54% and 75.34±3.49% to 88.68±2.76%, respectively. Total spawn production was 960, 862 and 734 kg, and the total revenue income from spawn sell was BDT 2,883,500, 2,355,100 and 1,844,800 (BDT 85 = 1 US$) in May, June and July, respectively. Estimated capital cost was BDT 87,90,000, while the operating costs were BDT 1,810,650; 1,555,105 and 1,267,680 in May, June and July, respectively. The calculated cost-benefit ratios in May, June and July were 1.59, 1.51 and 1.46, respectively. The hatchery got the highest net profit of BDT (Bangladeshi Taka) 1,041,906 in May due to the highest production and higher price of spawn, and the lowest profit of BDT 546,176 was obtained in July. So, May was found to be the peak breeding month of Ma Fatima Hatchery. The estimated cost-benefit ratio indicated that the spawn production through induced breeding techniques was profitable for the hatchery owners.

Infectious Fish Disease Occurrence in Carp Culture Ponds of West Godavari District, Andhra Pradesh, India

Aquaculture is one of the fastest growing food producing sector in the world. In India over the last three decades, aquaculture has developed significantly, earning considerable amount of foreign exchange, besides providing employment. India is basically a carp country. Where in the indigenous major carps: Catla (Catla catla), rohu (Labeo rohita), mrigal (Cirrhinus mrigal), exotic carps like common carp (Cyprinus carpio) grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmicthys molitrix) along with air breathing fishes, Clarias batrachus, Heteropneuestes fossils, Pangasius sps. are being widely cultured accounting for bulk of freshwater aquaculture production. In the last few years, the exotic catfish Pangasianodon hypophthalmus and pacu Piaractus branchypomus culure is also increasing. Tilapia and Pangasius are also offer opportunities for cage culture. The focus on the production of genetically improved tilapia for market as cheep source of proteins is also enhancing (Jelte de Jong, 2017). As the scope for horizontal expansion is limited, the current trend in aquaculture development is focused towards intensification of the culture practices. The frequent occurrence of diseases and epizootics are considered to be major bottlenecks for increasing production. The diseases are mostly bacterial and parasitic origin. The diseases account for 10-5 % towards the production cost (Sahoo, P. K. et al., 2017). India is basically a carp Freshwater aquaculture has been the main stay of Indian aquaculture, in terms of total quantity as well as its share in the domestic fish basket. India is called as carp country as carp production contribute in bulk (over 82%). In Andhra Pradesh fish and shrimp culture is income generating profession. The district West Godavari of Andhra Pradesh, is specifically the fish bowl of India, generating an amount of Rs. 15.00 crores annually. Semi intensive culture practice is common, in an area of more than 2.0 lakh acres. In course of expansion and intensification of this semi extensive culture practice of the Indian major carps, over the last three decades, many economically important problems have been identified which are threatening the sustainability of the culture system. Occurrence of diseases is one of such factor affecting the socio-economic status of aqua farmers. To overcome this, an intensive surveillance was carried to document the prevalence of various diseases, season of occurrence, disease diagnosis, etiological agents, mortality rates and controlling measures, so that the severe risk for sustainability and huge economic loss can be arrested. The frequency in occurrence of septicaemia, bacterial gill disease (bacterial), dactylogyrosis, paradactylogyrosis (parasitic) and argulosis are recorded. The incidence of diseases and mortality rate are high in winter season.

Carps, Catla catla, Cirrhinus mrigala and Hypophthalmichthys molitrix Are Resistant to Experimental Infection with Tilapia Lake Virus (TiLV)

Tilapia tilapinevirus, also known as tilapia lake virus (TiLV), is an emerging fish virus that primarily affects tilapines. However, the virus has also been detected in a few non-tilapines. As tilapia is generally farmed in polyculture systems along with carps in South Asian countries, there is a likelihood that TiLV-infected tilapia can transmit the virus to the co-cultured species. In view of the above, the susceptibility of three carp species, namely catla (Catla catla), mrigal (Cirrhinus mrigala) and silver carp (Hypophthalmichthys molitrix) was evaluated vis-à-vis tilapia, following experimental infection with TiLV. No clinical signs and histopathological alterations could be observed in carps. RT-qPCR revealed that TiLV copy numbers in liver and brain of all the three carps were almost negligible and did not show any increase with time, suggesting that the virus did not replicate in liver and brain, the target organs of TiLV. Further, TiLV could not be isolated from pooled liver and brain tissues of carps using permissive CFF cell line. On the contrary, in tilapia, typical clinical signs and histopathological lesions were observed and there was significant increase in TiLV copy number up to 6 days post-injection. Furthermore, the virus was successfully isolated from pooled liver and brain tissue of infected tilapia. From the above findings, it could be concluded that C. catla, C. mrigala and H. molitrix are resistant to TiLV infection and unlikely to be carriers for this virus.