Pratap Kumar Mukhopadhyay

Larval survival and growth in Wallago attu (Bloch and Schneider): effects of light, photoperiod and feeding regimes

Abstract An in-door rearing study was conducted for 11 days with Wallago attu larvae fed on live zooplankton alone (control) or combinations of zooplankton and dry feed containing either fish meal (F1), meat meal (F2) or shrimp meal (F3) under 24 h continuous light (24L), 12 h light–12 h dark (12L:12D), 24 h red light (24RL) or complete darkness (0L). The percent survival of larvae was significantly different (P

Nutrient digestibility and intestinal enzyme activity of Clarias batrachus (Linn.) juveniles fed on dried fish and chicken viscera incorporated diets

A feeding trial was conducted for 56 days to study the effect of replacement of fish meal by dried fish and chicken viscera, and a combination of oil cakes, in the diet of Clarias batrachus juveniles. The nutritional values of these by-products were studied through a digestibility experiment. No significant difference in nutrient digestibility was observed in different diets. Even 19.59% lipid in the diet of catfish did not affect the nutrient digestibility. Both amylolytic and proteolytic enzymes in the intestine of juveniles were studied. A decreased protease activity due to replacement of animal protein by plant protein and a decreased (P < 0.01) aspartate aminotransferase (ASAT) activity could be observed after inclusion of 22% of dried fish viscera in the diet of the catfish. Though body lipid content increased in fish fed a high level of lipid, fat-free body composition did not vary among the fish fed on different diets.

Utilization of fermented silkworm pupae silage in feed for carps.

Fermented silkworm pupae (SWP) silage or untreated fresh SWP pastes were incorporated in carp feed formulations replacing fishmeal. The feed formulations were isonitrogenous (30.2-30.9% protein) and isocaloric (ME = 2905-2935 kcal/kg). Feeding under a polyculture system consisting of 30% each of catla (Catla catla), mrigal (Cirrhinus mrigala) and rohu (Labeo rohita) with 10% silver carps (Hypophthalmychthys molitrix) was carried out in ponds to evaluate the nutritive quality of SWP silage. Survival rate, feed conversion ratio and specific growth rate, respectively, were 84.2%, 2.10 and 2.39 for fermented SWP silage, 65.8%, 2.98 and 2.26 for untreated SWP and 67.5%, 3.16 and 2.20 for fishmeal indicating clearly that the fermented SWP silage was nutritionally superior to untreated SWP or fishmeal. The dietary influence on the proximate composition of whole fish was marginal.

Evaluation of fermented fish offal in formulated diet of the Indian major carp, rohu, Labeo rohita [Hamilton]

There has been a considerable research effort towards utilization of less expensive renewable ingredients in fish diet formulations to alleviate problems related to shortage of quality fish meal (Pongmaneerat et al. 1993, El Sayed 1994, Rangacharyulu et al. 2003, Yang et al. 2004, Mukhopadhyay and Mitra 2007). Fish offal, which is generated in large quantities on a daily basis in the urban and sub-urban markets in India, has immense potential to be used as a predominant nutrient source in fish diet formulations. Very few studies have evaluated its efficacy, so far (Giri et al. 2000). In a preliminary investigation we observed the viscera of carps, which are discarded in bulk as offal in the retail fish markets contain a substantial amount of crude protein (31.5%–38.9%) and lipid (40.6%–43.8%) on a dry matter basis (Mondal et al. 2006). Collection of these wastes from the urban and suburban markets, treating them suitably to preserve their nutrients and finally recycling them into fish diet production can have a significant benefit in terms of abatement of pollution of environment as well as reduction in the recurring cost of fish production. Although dried fish, chicken viscera, and related animal by-products have been evaluated previously as protein resource in fish diet formulations (Saha and Ray 1998, Giri et al. 2000), efficacy of fish offal as such has not been ACTA ICHTHYOLOGICA ET PISCATORIA (2007) 37 (2): 99–105 DOI: 10.3750/AIP2007.37.2.06

Modulation of digestive enzyme activities during ontogeny of Labeo rohita larvae fed ascorbic acid enriched zooplankton

The effect of supplementation of ascorbic acid through enriched zooplankton [10%, 20% and 30% ascorbyl palmitate (AP) inclusion in diet of zooplankton] on different digestive enzyme activities during ontogeny of Labeo rohita larvae was studied from 4 day to 15 day post hatch. Ascorbic acid (AA) content in different groups of unenriched (8.6+/-0.71) and enriched zooplankton were, 750+/-29.3, 1409.1+/-45.5, 2009.21+/-199.2 mug/g respectively on dry matter basis with differences (P<0.05) between the treatments. A difference (P<0.05) was found in tissue AA level in different dietary groups. Low amylase, protease, lipase and alkaline phosphatase activities were present in rohu larvae from the mouth opening stage which showed increasing trend with the age of larvae and increasing dietary AA content. A clear dose-dependent modulation of digestive enzyme activities in response to 10%, 20% and 30% AP enriched zooplankton feeding was evidenced from positive correlations between dietary AA content with magnitude of elevation of enzyme activity in different groups. There were 57, 55, 29.2 and 2 fold increases in amylase activity; 7.35, 7.02, 4.43 and 2.73 fold increases in protease activity; 45.636, 41.50, 19.83 and 13.69 fold increases in lipase activity and 6, 5, 3, and 2 fold increases in alkaline phosphatase activity observed in the 15th day post hatch larvae fed 20%, 30%, 10%AP enriched and normal zooplankton respectively, than 4-day post hatch larvae of the respective groups. Enzyme activities were also positively correlated with specific growth rates of wet weight of rohu larvae at the 15th day post hatch. Increased AA might have played an important role in advancing morphological transformation of the digestive tract, protecting gastric mucosa and accelerating growth by the process of tissue formation, which necessitated the requirement of more nutrient thereby, increasing digestive enzyme activity. The regulatory role of AA in the modulation of different digestive enzymes activity and its physiological consequences of nutrient digestibility and utilization during ontogenesis could be extrapolated for better nutrient management of the larvae.

Partial Replacement of Fishmeal by Fermented Fish-Offal Meal in the Formulation of Diet for Indian Minor Carp Labeo bata

Fermented fish-offal (FO) meal was used as a protein supplement to replace fishmeal (FM) in the formulation of experimental diets for the Indian minor carp Labeo bata. The two supplementary diets, one containing 25% FM plus 25% FO and the other containing 20% FM and 30% FO, showed significantly higher digestibility, growth, and protein deposition than the reference diet containing 40% FM. Partial budgeting of diet formulation and net return revealed that 50% replacement of FM by fermented fish-offal meal rendered a total positive benefit of 134% as compared with the reference diet.

Supplementation of four non-conventional aquatic weeds to the basal diet of Catla catla and Cirrhinus mrigala fingerlings: Effect on growth, protein utilization and body composition of fish

Background. Our previous study has shown that four aquatic weeds viz. Asian watermoss, Salvinia cucullata ; water spinach Ipomoeareptans ; water chestnut, Trapanatans ; and lesser duckweed ,Lemnaminor ) from northeast India are important sources of proteins, vitamins and minerals, suitable for incorporation in fish diet. The aim of the present study was to compare the efficacy of these aquatic weeds based formulated diets on growth, feed utilization and nutrient turnover from feed to fish flesh of fingerlings of two species of Indian major carps: catla,Catlacatla (Hamilton, 1822), and mrigal,Cirrhinusmrigala (Bloch, 1795) . MaterialandMethods. The fingerlings were hand-sorted and distributed in 15 glass aquaria (each having 50 l capacity) at a stocking density of 5 fishes per aquarium. Five formulated diets (containing 26%–28% of crude protein approximately) were prepared and analyzed for proximate composition. The diets were fed to catla and mrigal fingerlings in triplicate treatments at the rate 3% of body weight for 60 days and fish performance in terms of growth, feed utilization and carcass composition was evaluated. Results. The whole body composition and energy content of C. catla fingerlings before and at the end of feed ing trials did not differ significantly ( P > 0.05), however, the proportion of crude lipid content was high when fed with diet F 2 (P < 0.05). In case ofC.mrigala, crude protein, as well as lipid contents, were significantly high er in all the groups of fish at the end of experiment as compared to the initial fish. The hepatic- as well as the muscle tissues of catla and mrigal fingerlings fed the diet F 2 (containing I. reptans ) displayed high contents of crude protein and vitamin E ( P < 0.01). Interestingly, although no difference in muscle glycogen level inC.mrigala was observed irrespective of the diet fed however, muscle and liver glycogen contents inCatlacatla finger lings fed F 2 diet was significantly higher compared to glycogen contents of these tissues of initial fish or fish fed with control diet. Conclusions. Presently reported study suggests that I. reptans , being a rich source of nutrients, is suitable for incorporation in fish diet forC.catla andC.mrigala fingerlings.

An Overview of Biology And Culture Potentials of Humped Featherback Chitala chitala (Hamilton, 1822) – A New Candidate for Aquaculture Diversification

ABSTRACT The humped featherback, Chitala chitala, a member of the primitive teleost lineage, is also a commercially important food, sport, aquarium and highly priced cultivable fish. It represents an appreciated fishery resource in Southeast Asia, particularly in India. Due to habitat degradation and overexploitation of natural populations, this species has been categorized as endangered (EN). Hence, large-scale farming of this new candidate species would ensure effective resource utilization, biodiversity conservation and widening the choice of the consumer by freshwater aquaculture diversification in India and South East Asia. The successful rearing of a species depends on adequate knowledge of its different biological attributes. This review is a consolidated report on the morphological characteristics, feeding habits, reproductive biology, early developmental ontogeny, and culture of humped featherbacks and explores the scope for future research to improve its present culture techniques.