Studies on food and feeding of marine demersal finfishes with special reference to trophic interactions

Food and feeding habits of fourteen demersal finfishes exploited off the Karnataka coast were studied to investigate trophic interactions within the marine food web. Index of Relative Importance (lRI),Ontogenetic, seasonal (pre-monsoon, monsoon and post-monsoon) variation in feeding and prey-predator relationship studies were conducted.The results of prey-predator trophic interaction studies identified four major trophic guilds based on the predators feeding similarity.Trophic guild I is 'copepod and detritus fceders'with an average group similarity of 61.4%. The second trophic guild, 'prawn and crab feeders'with an average similarity of 52.7%. 'Acetes feeders', the largest trophic guild with an average group similarity of 62.5%, composed of six demersal finfish species.The guild 'piscivores' is constituted by C. limba/us and P. arsius with an average similarity of 45%.For each predator, ontogenetic diet shift is common and is characterized by prey of low to high trophic level.Strong selection of certain prey types was observed in some predators while most of them avoided abundant prey.In addition to Acetes spp, strong predation impact was observed for penaeid prawns, epibenthic crabs and detritus.This information on trophic guilds and prey-predator interactions can be used to construct trophic model on the benthic ecosystem off Karnataka and to investigate fishery induced changes as well as predation impact of different animals on commercially important demersals

Studies in oleoresins an investigation into food colour from Indian chilli oleoresin

This thesis is essentially concerned with a study of the recovery of pungency-free colour matter from capsicum spice of Indian origin. A spice oleoresin may be defined as the total soluble extract of the spice in a specific solvent and embraces all the active components that contribute to aroma, taste and related sensory factors associated with the spice, together with varying amounts of pigments, plant waxes, resins and fixed oils. Whereas, in general, oleoresins are coveted for their flavour qualities, in some cases, the pigments present therein play a vital role in food technology Of these, capsicum oleoresin is the most outstanding, since it contributes both colour and flavour principles.

Studies on Lactic Acid Bacteria from Tropical Fish and Shellfish

In this study, an attempt has been made to gather enough information regarding lactic acid bacteria from fish and shellfish of tropical regions. The occurrence and distribution of lactic acid bacteria in fresh and frozen marine fish and shellfish, farmed fish and shellfish, cured and pickled fish and shellfish have been investigated. Lactic Acid Bacteria (LAB) have for centuries been responsible for the fermentative preservation of many foods. They are used to retard spoilage and preserve foods through natural fermentations. They have found commercial applications as starter cultures in the dairy, baking, meat, fish, and vegetable and alcoholic beverage industries. They are industrially important organisms recognized for their fermentative ability as well as their nutritional benefits. These organisms produce various compounds such as organic acids, diacetyl, hydrogen peroxide and bacteriocins or bactericidal proteins during lactic fermentations.Biopreservation of foods using bacteriocin producing LAB cultures is becoming widely used. The antimicrobial effect of bacteriocins and other compounds produced during fermentation of carbohydrates are well known to inhibit the growth of certain food spoiling bacteria as well as a limited group of food poisoning and pathogenic bacteria LAB like Lactobacillus plantarum are widely used as starter cultures for the Production of fish ensilage. The present study is the first quantitative and qualitative study on the occurrence and distribution of lactic acid bacteria in fresh and frozen fish and prawn. It is concluded that Lactobacillus plantaruni was the predominant lactobacillus species in fresh and frozen fish and shellfish. The ability of selected Lactobacillus cultures to grow at low temperatures, high salt content, produce bacteriocins, rapidly ferment sugars and decrease the pH make them potential candidates for biopreservation of fish and shellfish.

Biochemical Effect of Dicarboxylic Acids on Oxalate Metabolism in Experimental Rats and Studies on Oxalate Degrading Bacteria

The current study is an attempt to find a means of lowering oxalate concentration in individuals susceptible to recurrent calcium oxalate stone disease.The formation of renal stone composed of calcium oxalate is a complex process that remains poorly understood and treatment of idiopathic recurrent stone formers is quite difficult and this area has attracted lots of research workers. The main objective of this work are to study the effect of certain mono and dicarboxylic acids on calcium oxalate crystal growth in vitro, isolation and characterization of oxalate degrading bacteria, study the biochemical effect of sodium glycollate and dicarboxylic acids on oxalate metabolism in experimental stone forming rats and To investigate the effect of dicarboxylic acids on oxalate metabolism in experimental hyperoxaluric rats. Oxalic acid is one of the most highly oxidized organic compound widely distributed in the diets of man and animals, and ingestion of plants that contain high concentration of oxalate may lead to intoxication. Excessive ingestion of dietary oxalate may lead to hyperoxaluria and calcium oxalate stone disease.The formation of calcium oxalate stone in the urine is dependent on the saturation level of both calcium and oxalate. Thus the management of one or both of these ions in individuals susceptible to urolithiasis appears to be important. The control of endogenous oxalate synthesis from its precursors in hyperoxaluric situation is likely to yield beneficial results and can be a useful approach in the medical management of urinary stones. A variety of compounds have been investigated to curtain endogenous oxalate synthesis which is a crucial factor, most of these compounds have not proved to be effective in the in vivo situation and some of them are not free from the toxic effect. The non-operative management of stone disease has been practiced in ancient India in the three famous indigenous systems of medicine, Ayurveda, Unani and Siddha, and proved to be effective.However the efficiency of most of these substances is still questionable and demands further study. Man as well as other mammals cannot metabolize oxalic acid. Excessive ingestion of oxalic acid can arise from oxalate rich food and from its major metabolic precursors, glycollate, glyoxylate and ascorbic acid can lead to an acute oxalate toxicity. Increasedlevels of circulating oxalate, which can result in a variety of diseases including renal failure and oxalate lithiasis. The ability to enzymatically degrade oxalate to less noxious Isubstances, formate and CO2, could benefit a great number of individuals including those afflicted with hyperoxaluria and calcium oxalate stone disease.

STUDIES ON TAXONOMY, DISTRIBUTION, ECOLOGY AND REPRODUCTIVE POTENTIAL OF ROTIFERS FROM SELECTED CENTRES IN COCHIN BACKWATER SYSTEM, KERALA

The studies were conducted in nine stations with varying ecological characteristics along Cochin backwaters and adjoining canals. Many workers opined that the distribution of rotifers is cosmopolitan. The significance of rotifers as first food for early larvae was indicated by Fujita. Aquaculture is a fast growing field in fisheries sector and it is gaining more importance as the fish landings and supply are getting irregular. A consistent supply of fish/shellfish can only be achieved through aquaculture. The success of any culture activity depends on the timely production of seeds of finfishes/shellfishes. The availability of wild seed is seasonal and erratic. So, a dependable source of seed of fishes and shellfishes is possible only through large scale production in hatchery. A successful seed production activity depends on the availability of a variety of suitable live feed organisms in sufficient quantities at the proper time for use in the larval stages. As the live feeds promote high growth rates, easy digestion, assimilation and the quality of not contaminating the culture water when compared to other artificial feeds, make the culture of live feed organisms the principal means of providing food for the larvae of finfishes and shellfishes. Rotifers are considered to be an excellent and indispensable food for larvae of many finfishes and crustaceans. It (1960) was the first to culture Brachionus plicatilis for feeding marine fish larvae, and now it is being extensively used as live feed in hatcheries all over the world. They are a group of microscopic organisms coming under the Phylum Rotifera which comprises of about 2000 species. Their slow swimming habits, ability to tolerate a wide range of salinities, parthenogenetic mode of reproduction and ability to get enriched easily, make rotifers an ideal live feed organism. The major factors such as temperature, salinity and food that influence the reproductive potential and thereby the population size of rotifer, Salinity is one of the most important aspect influencing the reproductive rate of rotifers. The feed type and feed concentration play a vital role in influencing the reproductive rate of rotifers. For culture of rotifers, the commonly used micro algae belong to Chlorella, Nannochloropsis, Isochrysis and Tetraselmis. While some studies have suggested that, algal diet has little effect on reproductive rates in 1979 while using the rotifer, Brachionus plicatilis as feed for the larvae of red sea bream, Pagrus major. It is generally accepted that rotifers play a pivotal role in the successful rearing of marine fish larvae.

Studies on Modified Atmosphere Packaging of Pearl Spot (Etroplussuratensis) With Special Emphasis to Biochemical and Microbiological Parameters

A modified atmosphere may be defined as a packaging or storage of a perishable product in an atmosphere other than that of air. A modified atmosphere (MA) applies to food packaged products changes continuously throughout the storage period. The pearl spot (Etroplus suratensis) is an important brackish water fish belonging to the family Cichlidae. The present work was carried out to see the effect of modified atmosphere packaging on the shelf life fresh pearl spot stored in ice to extent the shelf life. The objectives of the present study are to study the suitability of Thermoformed Trays for modified atmosphere packaging, to standardize the most suitable gas mixture for modified atmosphere packaging pearl spot based on sensory evaluation, to find out the effect of modified atmosphere packaging in comparison to air packaging, to study the biochemical, microbiological, sensory and textural characteristics during storage, to study the safety concern regarding the Clostridium botulinum during modified atmosphere packaging, to find out the most suitable chemical quality indices for modified atmosphere stored pearl spot

Comparative Studies on the Abundance of Zooplankton in the Surrounding Sea & Lagoons in the Lakshadweep

Composition and distribution of various groups and species of zooplankton at Kavaratti, Agatti and Suhelipar atolls of the Lakshadweep group of islands are reported . Higher biomass and diversity occur in the sea surrounding atolls compared to lagoons . Copepoda forms the dominant component of zooplankton . Zooplankton washed across the reef into the lagoon may be serving as food to the reef community . No fauna endemic to lagoons are encountered.

Biochemical studies on some Tropical Esturine Zooplankton Species

Percentages of protein, carbohydrate and lipid which form the major biochemical constituents of 10 species of zooplankton from Cochin backwaters were estimated . Protein invariably formed the major constituent in terms of dry weight. Carbohydrate content was in general very poor . Both protein and lipid were low for organisms with higher water content and did not show any reciprocal relationship . The results in general supported the view that protein may function as a metabolic reserve in zooplankton and that the availability of a constant supply of food may render large amount of lipid storage unnecessary in tropical zooplankton.

Studies on the Deep - Water Crab Charybdis (Goniohellenus ) Smithii Macleay From the Seas Around India

The present study deals with a general introduction which outlines the objective of the study providing an exhaustive review of works on crabs with particular reference to deep-sea forms. In the first section, Taxonomy and Geographical disribution of the crab are dealt with. The species is described in detail based on several male and female specimens obtained from the pelagic and bottom collections, and its identity in Indian waters is established. It is also distinguished from a closely allied species so far not reported from Indian waters. The second section comprises the biology of the species and it is dealt with under four subheading, namely Habit and Habitats, Reproduction, Food and feeding and Proximate composition. The different habitats occupied by juveniles, subadults and adults of the species have been described and discussed in the light of available information on differential distribution of other related species. The reproductive biology is described in various details touching on gross anatomy and histology of the reproductive systems, spermatogenesis, oogenesis, size at maturity, ovarian maturation process, fecundity, egg carriage and breeding. The food and feeding habits of the species have been studied with reference to the different life stages such as juveniles, subadults and adults during the different phases of life based on stomach content analysis. The percentage of meat recovery and protein, carbohydrate and lipid content of meat have been described in the section dealing with proximate composition. In section three the distribution and abundance of the crab for the entire Indian EEZ and some contiguous ares have been described and illustrated in detail separately for pelagic and benthic realms. The size frequency disrtibution, sex ratios, length weight relationship and relative abundance of breeding population in the experimental catches have been dealt with in detail and discussed.

Studies on Synthesis And Nutritional Evaluation of Prawn Feeds

Chemical Oceanography Division, School of Marine Sciences, Cochin University of Science and Technology

Studies on the Bioactive Natural Antioxidants From Oilseeds

Antioxidants are substances that when present at low concentrations compared to that of an oxidisable substrate significantly delays or inhibits oxidation of that substrate in food products or in living systems. Antioxidants are either endogenous to the body or derived from the diet. Several types of synthetic antioxidants like BHT, BHA, TBHQ etc. are also used in the food industry. However, findings and subsequent publicity has fostered significant consumer resistance to the use of synthetic food additives as antioxidants, colourants etc. and therefore food industry is in search of potential natural antioxidants from edible sources.The major dietary sources of antioxidant phytochemicals are cereals, legumes, fruits, vegetables, oilseeds, beverages, spices and herbs. In the present study, we have focused on rice bran and its byproducts. Rice is one of the oldest of food crops and has been a staple food in India from very ancient times. It is also the staple food for about 60% of the world's population. Rice bran is a byproduct of the rice milling industry and is a potential commercial source of a healthy edible oil viz. rice bran oil and a variety of bio-active phytochemicals.Defatted rice bran (DRB), a byproduct of rice bran oil extraction, is also a good source of insoluble dietary fiber, protein, phytic acid, inosito I, vitamin B and a variety of other phytochemicals. Though the antioxidant potential of DRB has been demonstrated, it still remained a relatively unexplored source material, which demanded further investigation especially with regard to its detailed phytochemical profile leading to practical application. The focus of the present investigation therefore has been on DRB primarily to establish its phytochemical status and feasibility of using it as a source of bio-active phytochemicals and natural antioxidants leading to value addition of DRB otherwise used as cattle feed. To gain a better understanding of the value of rice bran as a source of phytochemicals, five popular rice varieties of the region viz. PTB 50, PTB 39, PTB 38, JA Y A, and MO 10 and a wild variety (oryza nivara) that is mainly used for medicinal applications in traditional ayurvedic system were characterized along with commercial samples of rice bran. The present study also explains the feasibility of a process for the extraction, enrichment, and isolation of antioxidant compounds from DRB. The antioxidant potential of the extracts were evaluated both in bulk oils and in food relevant model emulsions, using standard in vitro models. Radical scavenging effects, indicative of possible biological effects, were also evaluated.

Studies on new processing aids and other compounding ingredients in special purpose rubbers

In the first part of the study we probed the effectiveness of rice bran oil as a multipurpose compounding ingredient for nitrile (NBR) and chloroprene (CR) rubbers. This oil has already been successfully employed in the compounding of NR and SBR in this laboratory.In this context we thought it worthwhile to try this oil in the polar rubbers viz, NBR and CR also. The principle of like dissolves like as applicable to solvents is equally applicable while selecting a plasticiser, elastomer combination. Because of the compatibility considerations polar plasticisers are preferred for polar rubbers like NBR and CR. Although plasticisation is a physical phenomenon and no chemical reaction is involved, the chemical structure of plasticisers determines how much physical attraction there is between the rubber and the plasticiser. In this context it is interesting to note that the various fatty acids present in rice bran oil have a long paraffinic chain, characteristic of waxes, with an acid group at the end of the molecule. The paraffinic end of the molecule contributes lubricating effects and limits compatibility whereas the acid end group contributes some polarity and is also chemically reactive. Because of absorption of acid group on the surface of pigments, these acids will have active pigment wetting characteristics also. These factors justifies the role of rice bran oil as a co-activator and lubricating agent for NBR and CR. In fact in our study we successfully replaced stearic acid as co-activator and aromatic oillDOP as processing aid for CR and NBR with rice bran oil.This part of the study has got special significance in the fact that rubber industry now heavily depends on petroleum industry for process oils. The conventional process oils like aromatic, naphthenic and paraffinic oils are increasingly becoming costlier, as its resources in nature are fast depleting. Moreover aromatic process oils are reported to be carcinogenic because of the presence of higher levels of polycyclic aromatic compounds in these oils.As a result of these factors, a great amount research is going on world over for newer processing aids which are cost effective, nontoxic and performanance wise at par with the conventional ones used in the rubber industry. Trials with vegetable oils in this direction is worth trying.Antioxidants are usually added to the rubber compound to minimise ageing effects from heat, light, oxygen etc. As rice bran oil contains significant amount of tocopherols and oryzanol which are natural antioxidants, we replaced a phenolic antioxidant like styrenated phenol (SP) from the compound recipe of both the rubbers with RBO and ascertained whether this oil could function in the role of antioxidant as well.Preparation and use of epoxidised rice bran oil as plasticiser has already been reported.The crude rice bran oil having an iodine value of 92 was epoxidised in this laboratory using peracetic acid in presence of sulphuric acid as catalyst. The epoxy content of the epoxidised oil was determined volumetrically by treating a known weight of the oil with excess HCI and back titrating the residual HCI with standard alkali solution. The epoxidised oil having an epoxy content of 3.4% was tried in the compounding of NBR and CR as processing aids. And results of these investigations are also included in this chapter. In the second part of the study we tried how RBO/ERBO could perform when used as a processing aid in place of aromatic oil in the compounding of black filled NRCR blends. Elastomers cannot have all the properties required for a particular applications, so it is common practice in rubber industry to blend two elastomers to have desired property for the resulting blend.In this RBO/ERBO was tried as a processing aid for plasticisation, dispersion of fillers, and vulcanisation of black filled NR-CR blends.Aromatic oil was used as a control. The results of our study indicate that these oils could function as a processing aid and when added together with carbon black function as a cure accelerator also.PVC is compatible with nitrile rubber in all proportions, provided NBR has an acrylonitrile content of 25 to 40%. Lower or higher ACN content in NBR makes it incompatible with PVC.PVC is usually blended with NBR at high temperatures. In order to reduce torque during mixing, additional amounts of plasticisers like DOP are added. The plasticiser should be compatible both with PVC and NBR so as to get a homogeneous blend. Epoxidised soyaben oil is reported to have been used in the compounding of PVC as it can perfonn both as an efficient plasticiser and heat stabilizer.At present DOP constitute the largest consumed plasticiser in the PVC compounding. The migration of this plasticiser from food packaging materials made of PVC poses great health hazards as this is harmful to human body. In such a scenario we also thought it worthwhile to see whether DOP could be replaced by rice bran oil in the compounding of NBR-PVC blends Different blends of NBR-PVC were prepared with RBO and were vulcanized using sulphur and conventional accelerators. The various physical and mechanical properties of the vulcanisates were evaluated and compared with those prepared with DOP as the control plasticiser. Epoxidised rice bran oil was also tried as plasticiser for the preparation of NBR-PVC blends. A comparison of the processability and cure characteristics of the different blends prepared with DOP and ERBO showed that ERBO based blends have better processability and lower cure time values. However the elastographic maximum torque values are higher for the DOP based blends. Almost all of the physical properties evaluated are found to be slightly better for the DOP based blends over the ERBO based ones. However a notable feature of the ERBO based blends is the better percentage retention of elongation at break values after ageing over the DOP based blends. The results of these studies using rice bran oil and its epoxidised variety indicated that they could be used as efficient plasticisers in place of DOP and justifies their role as novel, nontoxic, and cheap plasticisers for NBR-PVC blends.

Studies on isolation and molecular characterization of plasmids from Vibrios

While the seriousness of the problem of antibiotic resistance is now recognized, the complex web of resistance linking humans, animals, and the environment is getting realized. More often, antibiotics are used as a preventive measure against diseases. Antibiotic use for agriculture leads to the increased resistance in the environment since antibiotics are inevitable element during agriculture/aquaculture and antibiotic residues are excreted as waste that is frequently spread onto farmland as organic fertilizer. Fecal bacteria survive long periods in the environment and spread through runoff into groundwater, rivers, and marine ecosystems.However, horizontal gene transfer occurs in the animals and guts of humans and in a variety of ecosystems, creating a pool of resistance in the rice fields and open waters. Even if people are not in direct contact with resistant disease through food animals, there are chances of contact with resistant fecal pathogens from the environment. Additionally, pathogens that are autochthonous to the environment can acquire resistance genes from the environment. Our study revealed that autochthonous , bacteria Vibrio spp gained antibiotic resistance in the environment. Further, it was evident that horizontal gene transfer occurs in Vibrio by means of plasmids, which further augments the gravity of the problem. Non-pathogenic bacteria may also acquire resistance genes and serve as a continuing source of resistance for other bacteria, both in the environment, and in the human gut. As the effectiveness of antibiotics for medical applications decline, the indiscriminate use of in aquaculture and in humans can have disastrous conditions in future due to horizontal gene transfer and the spread of resistant organisms: We must recognize and deal with the threat posed by overuse of antibiotics.