Loading...
Theses
Browse
8 results
Search Results
ThesisItem Open Access Utilization of prawn waste as pig feed(Department of Animal Nutrition, College of Veterinary and Animal Sciences, Mannuthy, 1991) Syam, Mohan K M; KAU; Sivaraman, EAn investigation was carried out to assess the feeding value of prawn waste as a partial or complete replacement of unsalted dried fish in the rations for growing – finishing pigs. Thirty – two Large White Yorkshire weanling pigs with an average body weight of 9.1 kg were distributed randomly and uniformly as far as possible to four groups (Groups 1, 11, 111 and IV) of eight animals each, with regard to age, sex and body weight and housed in pairs of the same sex. The four dietary treatments A, B, C and D were allotted to the pigs in the groups 1, 11, 111 and IV respectively. Of the total protein, 25 per cent in the diets A, B and C and 12.5 per cent in the diet D were provided as animal protein. Unsalted dried fish was used as animal protein source in the diets C and D. Diet C formed the control diet. In the diets A and B, 50 per cent and 100 per cent replacements respectively of animal protein from unsalted dried fish were made using dried prawn waste. All the animals were maintained on the respective diets with 18 per cent total protein upto an average live weight of 50 kg and with 14 per cent protein till they attained a body weight of 70 kg or 8 months of age, whichever was earlier, when they were slaughtered to study carcass characteristics.ThesisItem Open Access Studies on depuration of edible oyster Crassostrea madrasensis (Preston)(Department of processing technology, College of fisheries, Panangad, 1993) Usha, P T; KAU; Damodaran, NamboodiriOysters crassostrea madrasensis harvested from cochin back waters are commonly contaminated with low levels of food poisoning organisms such as E.coli, Salmonella, Shigella, Vibrio cholera, V-parahaemolyticus etc, heavy metals like cadmium, lead, copper, zinc, mercury etc and sand content. Depuration studies were conducted to find out any changes in the biochemical constituents such as total Nitrogen, salt soluble Nitrogen, Non protein Nitrogen, Ash and sand content. The studies revealed that there were no significant changes in the biochemical constituents during the 48th depuration period. Oysters were laboratory contaminated to levels in excess of 10000 cells /g with E.coli and it was cleansed from such oysters during purification in a laboratory depuration unit that used ultraviolet light and chlorination for sterilizing the depuration water. Depuration in sterilized water using ultra violet light treatment was found to be more efficient in cleansing the oyster of pathogen, E.Coli than using chlorination. Of the two salinity tested depuration of oyster in seawater at 35 ppt salinity gave better results compared t that in 30ppt salinity sea water both sterilised with uv light. Depuration of oyster in unsterile seawater and in seawater sterilised 10 ppm chlorination was found to be least effective in cleansing the oyster to the acceptable international standard of less than 2.3 E.Coli/g oyster meat within 48h depuration. There was no appreciated change in the sensory characteristics of oysters such as aroma, taste, and flavor. However there was significant change in the grittiness characteristics of oyster after 48h depuration. Depuration was not effective in removing heavy metals such as cadmium, lead, zinc, Tin and Mercury from the oyster within the depuration period of 48h.ThesisItem Open Access Breeding biology of Villorita cyprinoides (Gray) in relation to salinity gradients(Department of Fishery Biology, College of Fisheries, Panangad, 1991) Sudha, B Nair; KAU; Jose, T MThe present study was undertaken to investigate the influence of salinity variations on the breeding biology of populations of black clam Villorita cyprinoides (Gray), inhibiting two different cological zones of the Vembanad Lake. Two stations with perennial clam beds, but differing greatly in salinity conditions were selected for the study. Station I, in the northern side of Thanneermukkam barrier, has more influx of sea water and Station II, in the southern side has low saline influx. Monthly collections of black clams and bottom and surface waters were made from May 1989 to June 1990. Major environmental parameters such as salinity, temperature, dissolved oxygen and pH of bottom and surface waters were estimated with a view to understand the circannual variations within and between the stations. Among these, salinity was found to be the most important parameter showing prominent variations. At Station I, the bottom salinity values ranged from 0.0 to 18.12%0 and in Station II from 0.0 to 2.12%0. Histological studies of the clams collected from the two stations revealed that animals inhabiting Station I, a predominantly brackish water zone, have a protracted, almost year round breeding season extending from September to June with peak spawning during March to June and coinciding with the peak salinity levels and temperature. At Station II, a predominantly freshwater zone, the clams have a short duration spawning season extending from March to June with peak spawning during Apirl and May, again coinciding with the peak salinity levels and temperature. It is also observed that there exists a positive correlation between the bottom salinity and gondal maturation and spawning. Size – frequency studies of the calms collected from the two stations revealed that at Station I, the clam fishery was dominated by small sized animals, when compared to Station II. This may be related to the differences observed in the extend of spawning activity between the population of the two stations, resulting in the divergent apportionment of energy resource for somatic growth versus reproduction.ThesisItem Open Access Investigations on head drooping In head-on processed prawns(Department of Processing Technology, College of Fisheries, Panangad, 1994) Jose, V T; KAU; Sherief, P MHead drooping is the major quality problem associated with processing of headon prawns. The head drooping in head on prawns refers to the condition of oozing out of hepatopancreatic juice resulting from the breakage of the arthrodial membrane, which connects cephalothoraz of prawn to abdomen dorsally. The susceptibility of prawns to head drooping depends on the stability of the arthrodial membrane which in turn is determined by its biochemical composition. In this connection various biochemical constituents of the arthrodial membrane such as protein, phospholipid, moisture, calcium and cholesterol were analysed for two specied of prawn, Penaeus indicus and Penaeus monodon under three size groups (30/40, 50/60, and 70/80 pieces /kg). The activities of various hydrolytic enzymes of the hepatopancreas were also studied. The various biochemical constituets showed significant difference between species. Within the same species a size wise variation in the constituents of the arthrodial membrane and enzyme activity of hepatopancreas was observed. The various unit process such as hauling time, ice storage durations, freezing methods, cold storage durations and thawing methods were studied individually for their influence on head drooping. The study shows that the major determinants of head drooping in prawns are the biochemical composition of the arthrodial membrane and the easiness with which the hydrolytic enzymes of the hepatopancreas are released on postmortem handling and processing.ThesisItem Open Access Vitamin C requirement and its deficiency syndromes in Macrobrachium Rosenberg II juveniles(Department of Aquaculture, College of Fisheries, Panangad, 1996) Gijo Ittoop; KAU; Sebastain, M JAn experiment was conducted to study the influence of dietary vitamin e on growth, survival, food conversion ratio, moulting rate and whole body ascorbic acid content of juvenile Macrobrachium rosenbergii, to determine the optimum dietary requirement of vitamin e and to characterise the deficiency syndromes, if any. Juvenile prawns kept under defined environmental conditions were fed casein based semipurified diets containing eight levels of vitamin C. CVC - F 90, a hydrogenated vegetable oil coated form of vitamin C with 90% available ascorbic acid was used as the vitamin source. Growth, survival, food conversion ratio, moulting rate and whole body ascorbic acid content were found to be significantly affected by dietary vitamin C (P≤ 0.01). Below a level of 75 mg CVC - F 90 per kg of dry diet, deficiency syndromes like poor growth, survival and food conversion, incomplete moulting and black lesions at the tip of walking legs were noticed. The maximum weight gain of 194.92% was obtained with a dietary level of 150 mg eve - F 90 per kg dry diet. Non-linear regression estimate based on percentage weight gain showed the optimum requirement to be 200.3 mg CVC - F 90 per kg dry diet which is equivalent to 182.97 mg AAE / kg dry diet. The tissue ascorbic acid level seemed to reflect dietary levels of Vitamin C. About 15 µ gm tissue ascorbic acid / g was required for maximum growth and survival.ThesisItem Open Access Effect of sedatives on penaeus monodon fabricus seed under oxygen packing for transportation(Department of Aquaculture, College of Fisheries, Panangad, 1991) Joshi, K; KAU; Jayasree Vadhyar, KThe study was performed with the objective of selecting a sedative at a suitable dose and testing its effect along with other factors viz. packing density, salinity and temperature on the P.mondon seed under oxygen – packed transport conditions. The selection of a sedative at an appropriate dose, from those tried viz. chloral hydrate, MS-222 and tertiary butyl alcohol, was made by conducting statistically designed experiments on the survival of the treated and untreated prawn seed for 72 hours in open containers and on the metabolic activities of the treated and untreated prawn seed for 2 hours. The experiment to find out the effect of the selected sedative was carried out in specially designed hard plastic containers fitted with facilities fpr packing oxygen under uniform pressure. The experiment was conducted as an asymmetrical factorial experiment with 4 levels of packing density (200/1, 400/1, 600/1 and 800/1) and 2 levels of sedation (without and with sedation), salinity (25 ppt and 20ppt) and temperature (29+ 10C and 23 + 20C). Chloral hydrate was selected at a dose of 400 ppm for application on P.monodon post –larvae under oxygen – packed conditions. The application of chloral hydrate on the prawn seed under oxygen packing at the selected dose evidently showed a negative effect. A lower dose (300 ppm) than the selected dose, studied separately, also showed similar results under oxygen packing . An increase in packing density decreased the time of initial mortality and percentage survival. At packing densities of 200/1, 400/1, 600/1 and 800/1, the safe durations of transport (duration of 100% survival) were 7.5 h,5 h, 3.5h and 2.5 h respectively at ambient temperature of 29+ 10 C. In P.monodon seed transport the number of seed has been found as more important than their weight in deciding the survival. A high salinity of 25 ppt was found better than a lower salinity for P.monodon seed transport. Lowering of temperature of the packing medium, rather than applying sedatives or lowering of salinity, has been found as a suitable method for increasing the survival during oxygen – packed transport of P.mondon seed. At the lowered temperature of 23+ 20C significantly longer duration of 100% survival (15h at 200/1 and 5 h at 800/1) and better percentage survival at 24 hours (92.5% at 200/1 and 83.13% at 800/1) than at the ambient temperature could be observed.ThesisItem Open Access Studies on texture and collagen content of commercially important tropical fishes(Department of Processing Technology, College of Fisheries, Panangad, 1991) Femeena Hassan; KAU; Sajan GeorgeStroma proteins refer to slightly soluble proteins which are obtained after removing water and salt, soluble proteins in the muscle. The main constituent of stroma protein is collagen. The role of collagen in contributing to the texture and gaping of fish fillets has been studied using six commercially important fish species of India VIZ. sardine (SardineIla lonqiceps) ,mackeral ( RastralIiger kanaqurta ) , tilapia ( Oreochromis mossambicus ) , common carp (Cyprinus carpio), tuna (Euthynnus affinis) and shark (Scoliodon sorrakowah). The texture of raw fish meat was found to be influenced by the content of collagen in fish muscle. A significant correlation (P > 0.05) was obtained between soluble, insoluble and total collagen contents, and toughness of raw meat, as determined by sensory evaluation and two types of texturometers. Significant correlation was also obtained between actomyosin content and toughness of raw meat, determined either by subjective or objective methods (P > 0.05), but not to the extent of soluble or total collagen. In the case of cooked meat , although a significant correlation (P> 0.05 ) was obtained between actomysin content and cooked meat toughness ,no such correlation could be established between collagen content and cooked meat toughness. Stroma proteins seem to be important in deciding the texture of raw meat, whereas, In the case, of cooked meat, myofibrillar proteins are probably involved. The gaping phenomenon was studied in frozen fillets stored for a period of three months. A slight increase in gaping was noticed during storage period. However, this was not found to be statistically significant. Further studies have to be carried out to get a clear cut idea about the influence of collagen on gaping phenomenon in frozen stored fish. The two types of texturometers fabricated, spring - operated and weight - operated, were found suitable for assessing the toughness of raw fish meat, but not. Cooked meat.ThesisItem Open Access Studies on the effect of purging the freshwater prawn Macrobrahium rosenbergii in extending its iced storage life(Department of Processing Technology, College of Fisheries, Panangad, 1995) Sudhir, B; KAU; Krishnakumar, SIn this study the effect of purging the prawn Macrobrachiumrosenbergiito improve its quality during iced storage was studied. Various biochemical and sensory changes that occurred during iced storage was observed. Experiments were done both for headless and headon prawns. For the headless prawns the treatments were (1) freshwater purged, and (2) purged and further chlorine dipped and the purging time was 5 hrs in a 500 litre tank. For the headon prawns purging in running water in a 5000 litre tank for 18 hrs was done. Both experiments were done with a control of unpurged prawns. The headless prawns kept longer than the head on product style more so perhaps due to the effect of beheading. Analysis of variance for alpha amino nitrogen, TVB, NPN, pH and sensory evaluation showed significant difference between purged and unpurged samples in the headon product sytle, the purged sample being of better quality. Similar results were not evident in the case of headless scampi. Longer duration of purging for 18 hrs or longer seems to have an influence on quality. For the headon prawns the acid insoluble ash showed a significant difference between treatments indicating the success in flushing the gut contents by purging. Sensory evaluation showed that headless and headon prawns were acceptable for more than 10 and 7 days respectively. Mushiness was not observed in the headless prawns but started from the third day for the headon control and the fifth day for the purged prawn. In headon prawn presence of black vein was reduced considerably by purging. Thus it was seen that there was an improvement in the general quality of the prawn due to purging.