[Show abstract][Hide abstract]ABSTRACT: Many of the microalgae have immense potential in aquaculture as a means of enriching zooplankton for feeding fish and shellfish larvae. In addition to protein and energy supply, they provide other key nutrients such as vitamins, essential polyunsaturated fatty acids (PUFA), pigments and sterols, which are transferred through the food chain. Development of marine finfish larviculture depends on very complex food and feeding behaviour. The challenges and hurdles in larval fish nutrition hinder progress in hatchery technology of many species. The microalgae play a vital role here to meet the nutritional requirement of many of the finfish and shellfish larvae. Apart from the commonly mass cultured and used microalgae in aquaculture, many of potential microalgal species occur natural waterbodies like backwaters and estuaries, which can be utilized for better larval survival and health. For the isolation of potential microalgal species from an estuarine area (Muttukadu, Tamil Nadu, India) the microalgal biodiversity has been studied based on certain diversity indices for the past one year. Various isolation techniques were applied for the isolating the microalgal strains. Pure isolates were developed in indoor laboratory and analyzed the nutrient profiles of the biomass. Based on the profile, potential species were selected to use in larval rearing of finfish and shellfish. Trials were conducted and evaluated the suitability of different microalgal isolates in Mud crab (Scylla serrata) and Milk fish (Chanos chanos) larval rearing, two important species for brackishwater aquaculture. Results indicated the scope for using mixed algal culture for better larval survival.
[Show abstract][Hide abstract]ABSTRACT: To evaluate the effect of periphyton based system, an on-station grow-out trial of black tiger shrimp, Penaeus monodon was carried out for 130 days using with (Ts) and without (Tc) submerged substrates. P. monodon was stocked at 8 nos. m(-2), and bamboo substrates (1.8 x 0.06 m) were fixed in treatment ponds @ 2000 numbers ha(-1) for development of periphyton. Provision of substrate increased the transparency (p<0.01) and reduced the turbidity (p<0.05) in treatment ponds compared to control. Similarly, comparatively lower level of total ammonia -N and nitrate -N were recorded in substrate based ponds compared to control. Periphyton biomass in terms of dry matter and ash free dry matter over substrates were 5.9 +/- 0.7 and 3.0 +/- 0.4 mg cm(-2) respectively. Chlorophyll a level in water column was 15.22 +/- 6.97 and 19.06 +/- 8.68 mu g L-1 in Ts and Tc ponds respectively. At the end of the grow out trial, a higher average production of 1640 kg ha' with an average body weight (ABW) 25.85 +/- 2.62 g was obtained in Ts compared with control, Tc (1390 kg ha(-1) production and 22.00 +/- 2.83 g ABW). About, 29% improvement in feed conversion ratio (1.15 +/- 0.42) noticed in substrate based ponds compared to control ponds (1.48 +/- 0.02). Regression trend for length weight analysis indicated that growth exhibited an isometric pattern with better Fulton condition factor (0.83) in tiger shrimp reared in substrate based system than in control ponds (0.82). Better growth performance of tiger shrimp in substrate based system indicates utilisation of available natural food and natural productivity as periphyton by cultured shrimps.
Article · Oct 2015 · Indian Journal of Geo-Marine Sciences
[Show abstract][Hide abstract]ABSTRACT: It has been widely accepted that the growing future demand for aquatic products will have to be met by aquaculture. By year 2020, worldwide aquaculture is projected to supply about 120–130 million tonnes of fish to meet the estimated demands (Rana et al. 2009; FAO 2012). Since feed is the single largest operational expense (between 50 and 60 %) in aquaculture, feed cost determines the profitability and sustainability of this agribusiness activity. Although aquaculture supplied more than 63 million metric tonnes of fish to the world’s human food basket in 2011, only two-thirds of this is produced from artificial feeding, and the rest is contributed by non-fed species. However, the percentage contribution by non-fed species is showing a declining trend from more than 50 % in 1980 to the present level of 33.3 %, indicating the significance of the formulated feed in global aquaculture industry and the further increase in demand for formulated feed and ingredients (FAO 2012).
[Show abstract][Hide abstract]ABSTRACT: To evaluate the effect of periphyton, an on-station grow out trial was conducted for 130 days with tiger shrimp, Penaeus
monodon @ 8 nos. m
in zero water exchange ponds. Bamboo poles (1.8×0.06 m) were fixed @ 2000 nos. ha
ponds for periphyton development. Total bacterial count (TBC) in water was significantly lower (p<0.05) in periphyton
based ponds (83.50±11.86×10
) compared with control (288.00±90.15×10
). The total Vibrio count
(TVC) in water had similar pattern which was 35.3% lower in treatment group compared to control. The TBC and TVC
in periphyton biomass over the submerged substrate were 333.13±114.14×10
respectively. At the end of the culture period, higher haemocyte count (p>0.05) (10.83±0.71×10
) and prophenol
oxidase activity (p<0.05) (8.65±0.47 U) was recorded in treatment ponds compared to control (9.38±0.47×10
and 5.18±0.51 U). In pathogen clearance test, treatment group recorded significant reduction (p<0.05) of Vibrio harveyi,
3 h post-inoculation. At the end of the trial, 17.90% gain in production and 22.29% reduction in FCR was observed in
periphyton group compared to control.
[Show abstract][Hide abstract]ABSTRACT: The predictions of climate change during the recent decades viz., consistent warming trends (increase in frequency of hot days and multiple-day heat wave), increase in extreme rains, and more frequent and intense extreme weather events (flood, cyclone and drought) has greater impact on aquaculture. This impact has been disproportionately felt by small-scale farmers who are already amongst the poor and vulnerable members of the society. The present study in West Godavari District of Andhra Pradesh documented the climate change events experienced by aqua farmers in brackishwater and freshwater areas and their perceptions, attitudes, risk management behaviour, adaptive capacities and impacts on aquatic farming systems through focus group discussion (FGD), extensive survey of 120 farmers through standard questionnaires, and stakeholder workshop (SW). Assessment based on consequence and livelihood scores revealed that seasonal variations with 20- 40% loss in production was the highest risk in both the areas followed by cyclone in brackishwater and high temperature in freshwater areas. Though not very common in every year, cyclones, the major extreme climatic event results in 50 to 100% loss in production. Among the studied aqua farmers, 14% were highly vulnerable to climate change, whereas 55% were moderately vulnerable. Farmer’s adaptation measures, science and technology solutions and policy adaptation measures are discussed to make aquaculture as climate resilient.
Full-text available · Article · Dec 2013 · Journal of agrometeorology
[Show abstract][Hide abstract]ABSTRACT: This article presents the nutritional value of shrimp on the strength of its nutrient composition and daily value (DV%). With its relatively lower lipid content (~ 1%), the DV (%) of 100 g shrimp for an adult human is 75%, 70% and 35% for eicosapentanoic acid + docosahexanoic acid, essential amino acids (methionine, tryptophan and lysine) and protein respectively. The lower atherogenic (0.36) and thrombogenic (0.29) indices of shrimp show its cardio-protective nature. The controversy relating to shrimp cholesterol and the overall health benefits of eating shrimp are discussed to indicate that shrimp should be a regular item in the diet of normolipidemic peoples.
[Show abstract][Hide abstract]ABSTRACT: An eight week growth trial was conducted to study the effect of replacement of fish meal with processed chicken waste meal (CWM) in the diet of Asian seabass, Lates calcarifer. Analysis of CWM showed that it has 53% crude protein and 32% crude lipid. Effect of replacement of fish meal (FM) with CWM was carried out by including CWM at 0, 5, 10, 15 and 20% (W/W) levels in an isonitrogenous (40%) and isolipidic (10%) diet. The experiment was carried out in a completely randomised design with three replicates for each treatment and each replicate containing ten animals (average initial body weight of 3.09 +/- 0.04 g). The results showed that there was no significant (p>0.05) difference in the final body weight (FBW), weight gain %, feed intake, feed conversion ratio (FCR), condition factor (CF) and average daily gain (ADO) in the fish, fed with diets containing CWM upto 10%. Inclusion of CWM at more than 10% level showed a significant (p<0.05) reduction in the growth parameters, compared to control diet. There was no significant difference in survival rate among the fish fed with different experimental diets. Similarly, hepatosomatic index (HSI) and viscerosomatic index (VSI) showed no significant difference (p>0.05) among the treatment groups. The results from this study indicate that the CWM is a potential ingredient in the diet of Asian seabass L. calcarifer and it can be included up to 5-10% levels, replacing fish meal. However further studies are needed to optimise the level of CWM in the diet of seabass.
[Show abstract][Hide abstract]ABSTRACT: Changes in the free and total amino acids in embryonic stages of eggs from captive bred greasy grouper, Epinephelus tauvina (Forskal), were analyzed. The fertilized grouper eggs contained 4.08±0.06 μg/egg free amino acids and 23.22±0.31 μg/egg total amino acids. Indispensable leucine, lysine, valine, and dispensable alanine, glutamic acid, and proline were the most prevalent total amino acids while indispensable isoleucine, leucine, lysine, and dispensable alanine, glutamic acid, and serine dominated the free pool. Free amino acids constituted 17.56±0.32% of the total amino acids in the fertilized eggs, decreasing to 14.75±0.25% and 7.48±0.24% in the gastrula and pre-hatch stages, respectively, due to catabolic and anabolic utilization of the free amino acids in embryonic development. There were wide variations in the loss of individual free amino acids during embryonic development: losses of arginine, lysine, threonine, alanine, aspartic acid, glutamic acid, and glycine were very high (>70%) compared to losses of methionine, phenylalanine, valine, cystine, and proline (<40%). Approximately 50% of the disappeared free amino acids was used for anabolic purposes, i.e., protein synthesis, and the remaining 50% was used for catabolic energy. Retention of indispensable amino acids for protein synthesis was higher than retention of dispensable amino acids.
Article · Jan 2013 · The Israeli journal of aquaculture = Bamidgeh
[Show abstract][Hide abstract]ABSTRACT: Silk cotton cake (SCC) was incorporated in the practical diets of tiger shrimp, Penaeus monodon at 5 different levels (0,2.5, 5.0, 7.5 and 10.0%) by replacing fish meal. Growth cum digestibility study was conducted for 45 d in 5001 experimental tanks using shrimps weighing 2.09 ± 0.06 g with three replications for each treatment. There was significant (p<0.05) reduction in specific growth rate (SGR) and daily growth coefficient (DGC) in shrimps fed diets having more than 2.5% SCC compared to other treatments. Apparent crude protein, lysine and methionine digestibilities decreased (p<0.05) in shrimp fed with more than 2.5% SCC incorporation. The free amino acid profiles of shrimp muscle at 4 h post-feeding indicated significantly (p<0.05) lower levels for lysine and methionine in shrimp fed with higher levels of SCC. Post-prandial ammonia nitrogen excretion (PPANE) on hourly basis revealed that incorporation of SCC has greatly influenced the N excretion. SCC incorporation has not affected the haemolymph protein concentration up to 7.5% and the haemocyanin content up to 5% inclusion. The experimental results indicate that SCC can be incorporated up to 2.5% in the diet of black tiger shrimp P. monodon.
Full-text available · Article · Oct 2012 · Indian Journal of Fisheries
[Show abstract][Hide abstract]ABSTRACT: Among the emerging diseases in shrimp aquaculture, monodon slow growth syndrome (MSGS) is a major concern in South and Southeast Asia. Shrimp farming in Thailand was severely affected during 2000-2002 due to MSGS, which caused an economic loss, of about US$ 300 million. MSGS is characterized by abnormally slow growth with coefficients of size variation of >35 %, that has impacted P. monodon production in Thailand. A new shrimp virus, Laem-Singh virus (LSNV) was identified to be associated in MSGS affected shrimp. LSNV a RNA virus of about 25 nm diameter is phylogenetically related to the insect-borne viruses in the families Barnaviridae, Tymoviridae and Sobemoviridae an important histopathological observation is exclusively noticed in growth-retarded shrimp. The LSNV infections have been confirmed in various organs of infected shrimp such as lymphoid organ, gills and nervous tissues by various diagnostic techniques such as reverse transcription polymerase chain reaction (RT-PCR), in situ hybridization, quantitative real-time RT-PCR and reverse transcription loop-mediated isothermal amplification combined with a lateral flow dipstick (RT-LAMP-LFD) and these tools are available for the diagnosis of LSNV. Recently, an integrase containing element has been identified in absolute association with LSNV in stunted growth shrimp. The transmission of LSNV through horizontal and vertical routes has been experimentally demonstrated. The known natural host-range of LSNV includes P. monodon and other penaeid shrimp. The putative RdRp gene involved in replication of LSNV was targeted for dsRNA-mediated gene silencing and appeared to be effective in a dose-dependent manner. Since the discovery of LSNV in 2006 in Thailand, it has been added to the list of viruses to be excluded from domesticated specific pathogen-free stocks of P. monodon and it has been recommended that shrimp farmers avoid stocking post larvae positive for LSNV to prevent MSGS in their farms.
[Show abstract][Hide abstract]ABSTRACT: Replacement of fish meal in marine shrimp feeds is assuming greater importance due to increasing economic and ecological considerations. This study evaluated sunflower cake as a replacement for fish meal in tiger shrimp Penaeus monodon juveniles reared both in tanks and in net cages at 26-33 ppt salinity. Five practical diets were prepared by incorporating sunflower cake at 0, 2.5, 5, 7.5 and 10% level by replacing fish meal. The essential amino acid index (EAAI) of test diets ranged from 0.91 to 0.88. Growth and digestibility study was conducted for 45 d in 500 L experimental tanks shrimp weighing 0.51±0.02 g with three replications for each treatment. There were significant (P<0.05) reductions in daily growth coefficients and protein utilization efficiency in shrimp fed with diets having above 2.5% sunflower cake in experimental tanks. The lysine and methionine digestibility (92.4±0.11 and 93.4±0.01%, respectively) was significantly (P<0.05) higher at 2.5% level inclusion than at 10% level (81.67±0.12 and 83.36±0.17%, respectively). The free amino acid profiles of shrimp muscle at 4 h post feeding indicated significantly (P<0.05) lower levels for isoleucine, leucine, lysine and valine in shrimp fed with higher level of sunflower cake. The decreased levels of these essential amino acids could have hampered protein synthesis and in turn growth. With three dietary treatments (0, 5 and 10% sunflower cake diets) a 10-week growth trial was also conducted in net cages with tiger shrimp juveniles weighing 0.2 g. Significantly (P<0.05) lower daily growth coefficients (%/d) were observed in shrimp fed with 10% sunflower cake diet (1.642±0.017) compared to control (1.774±0.024). The results indicate that sunflower cake can be incorporated up to 5% by replacing 20% of fish meal in marine shrimp P. monodon practical feeds without compromising growth.
Full-text available · Article · Jun 2011 · Indian Journal of Geo-Marine Sciences
[Show abstract][Hide abstract]ABSTRACT: A formulated pellet and ball form feed with 41.6% crude protein, consisting of fish meal, squid meal, shrimp meal, mantis shrimp meal, soyabean meal, bread flour and other additives was evaluated for mud crab, Scylla serrata. Fish meat (tilapia), which is conventionally used for feeding mud crab by farmers was used as control. Crabs with average weight of 151.7 g were stocked in 500 1 oval shaped FRP tanks containing seawater @ 2 crabs per tank with six replicates per treatment. The crabs were fed daily with dry pellets @ 10% of their body weight in a 30-day feeding trial. The crabs showed excellent acceptability of the compounded feed from the start and had shown a weight gain of 36.7% and a feed gain ratio (FGR) of 2.94, compared to 33.5% weight gain and 5.56 FGR shown by the crabs fed with fish meat. The amino acid profiles of the feed, fish meat and the crabs before and after the feeding trial showed that the ratio of indispensable amino acids (IAA) and the dispensable amino acids (DAA) is same (0.8) for both feeds. Performance of dry as well as semimoist form of pelleted feeds also studied. In a 30-day feeding trial, the weight gain of crabs fed dry feeds was significantly higher (p<0.05) compared to moist feeds. It was due to the higher wastage of feed (30.4%) in semi-moist feeds compared to the dry feeds (17.2%). There was no difference in the FGR shown by different feeds. The proximate composition of crabs fed with the different forms of feed also did not show any variation. Dry pellet feed is preferred over the semi-moist form of feed for feeding mud crab.
Full-text available · Article · Apr 2011 · Indian Journal of Fisheries