Theses

Browse

Search Results

Now showing 1 - 9 of 11

Open Access
Effect of eyestalk ablation on growth and reproduction of macrobrachium equidens (Dana)
(Department of Aquaculture, College of Fisheries, Panangad, 1994) Bijulal, P S; KAU; Thampy, D M
The objective of the present study is to evaluate the effect of eyestalk ablation on survival, growth, food conversion and reproduction of adult Macrobrachiumequidens. In the first experiment conducted for 35 days, unilateral eyestalk ablation, bilateral ablation and control treatments were employed at four level of salinities viz 5, 10, 15 and 20 ppt. Complete mortality in bilateral ablation and survival rates of 40.625 % and 68.75% for unilateral and control treatments were recorded at the end of the experiment, the values ranging significantly. The four salinity levels applied did not significantly affect survival. The difference in growth between ablated and unablatedtreatments was insignificant in terms of percentage gain, specific growth rate and average daily percentage gain in terms of length and weight. Salinity levels also showed insignificant difference in growth. Food conversion rate was significantly better in ablated treatment. The different salinity levels tried showed significant difference with regard to food conversion, being better at 20 ppt. In the second experiment conducted for 60 days on females, eyestalk ablation was found to enhance ovarian. In the second experiment conducted for 60 days on females, eyestalk ablation was found to enhance ovarian development in terms of the number of spawns per female. Fecundity, absolute fecundity, and incubation period were not significantly affected although a marginal increase in absolute fecundity could be observed . In the experiments conducted on males it was found that growth rate and cheliped development were significantly better in ablated ones. The number of spines in the appendix masculine, length and biomass of the androgenic gland and width of vas deference, did not show significant variation, although a marginal increase in the biomass of the androgenic gland and the number of spines in appendix masculine was observed in ablated treatment. The different eyestalk ablation experiments have shown that in females destalking does not stimulate growth but there is better response for reproduction, whereas in males there is better growth and only marginal response to reproduction.
Open Access
Conditions for oxygen-packed transportation of penaeus indicus seed
(Department of Aquaculture, College of Fisheries, Panangad, 1994) Geetha Rani Mani, V; KAU; Jayasree Vadhyar, K
The effect of four levels of packing density, (200PL/1, 300PL/1, 400PL/1 and 500PL/1), three levels of salinity (20ppt, 25ppt and 30ppt) and two levels of temperature (30_+ 1°C and 23 + 2°C) on the oxygen consumption rate of Penaeus indicus post-larvae (PL20) was investigated in a closed type respirometer. The dissolved oxygen in the test chamber decreased with the oxygen consumption of the animals. Oxygen consumption was found to vary with ambient oxygen levels at the different packing densities. Among the three salinities, and two temperatures, the lowest rate of oxygen consumption was recorded at 25ppt and 23 +_ 2°C. The effect of these factors on the duration and survival of transportation of the shrimp seed in specially designed hard plastic containers fitted with facilities for oxygen packing under uniform pressure (0.2 Kg/cm2) showed that oxygen packing in hypothermal conditions could help in increasing duration and survival. Salinity of 20-25ppt was found to give longer duration of survival. With increase in packing density, there was considerable reduction in the duration and survival of transportation of the seed. Cannibalism was observed as the major cause of mortality and it could be reduced by lowering of temperature. 200PL/1 could be transported with 100% survival within 6.5-8.5h at ambient temperature of 30+- 1°C under the afore-mentioned type of oxygen-packing. By lowering the temperature to 23 +-_ 2°C it was possible to safely transport with 100% survival the same numbers for more than 20h. Corresponding duration at 500PL/1 with 100% survival was 1-1.5h at ambient temperature and 4-5h at lowered temperature. To reduce cannibalism at ambient temperatures, hollow plastic translucent habitat material was incorporated into the oxygen-packed jars. This experiment was conducted at 25ppt salinity at different packing densities of 200PL/1, 300PL/1, 400PL/1 and 500PL/1. Relatively longer duration and higher survival was observed only at higher packing densities of 400PL/1 and 500PL/1 with the introduction of the habitat material. Water quality parameters in the experimental jars were analysed initially and finally at 70% survival rate. The reduction in dissolved oxygen levels in the oxygen-packed jars was well above the lethal limits even at the highest packing density of 500PL/1 at 70% survival. The decrease in dissolved oxygen levels and increase in ammonia-N and free carbon dioxide, differed with the duration of packing, temperature and packing density.
Open Access
Evaluation of growth in Penaeus Monodon Fabricius by incorporation of selected nonhormonal growth promoters in the diet
(Department of Aquaculture, College of Fisheries,Panangad, 1997) Vinodh, M P; KAU; Susheela, Jose
The effect of three growth promoters viz. Chitin, chitosan and glucosamine each at three levels (0.25, 0.5 and 1g per 100g diet) were evaluated in P.monodon early juvenile for a period of 70 days. The three growth promoters at three level were tested with 3 replicates for each treatment. The growth promoters were incorporated into a soyflour clam meal based practical diet containing 40% protein and fed to the shrimps adlibitum. The results showed that the overall growth was not affected by dietary inclusion of chitin though the growth rate at 0.25g chitin per 100g diet was comparatively better than that of the control diet. Chitin does not seem to have any effect on specific growth rate of the juveniles although incorporation at 0.25g/100g diet improved the food conversion of the animal significantly over the control. Percentage survival values were also not significant at any level of incorporation. It does not seem to improve protein efficiency ratio and productive protein value too. Incorporation of chitosan at 0.25 and 0.5g/100g diet significantly improved the weight gain, specific growth rate, food conversion ratio, protein efficiency ratio and productive protein value. However inclusion of chitosan at 1g/100g diet did not have any effect on growth though it significantly improved food conversion ratio, protein efficiency ratio and productive protein value. None of these treatments had any effect on survival of the animal. Incorporation of glucosamine into the diet at 0.25g/100g diet was found to be the most efficient amongst the different treatments as evidenced by various growth parameters. It was significantly different from all other treatments in terms of growth, productive protein value and protein efficiency ratio. However it was not significantly different from glucosamine incorporation at 0.5g/100g diet in terms of specific growth rate and food conversion ratio. Enhancement of glucosamine level to 1g/100g diet was found to give poor result compared to the control. The survival rate of shrimps were not significantly different among the treatments. Hence in the present study, glucosamine was found to be superior to chitin and chitosan as a growth promoter and the optimum level was identified as 0.25g/100g diet for P.monodon juveniles
Open Access
Effect of different dietary levels of lecithin on growth,survival,moulting and body phospholipid levels in Macrobachium Rosenbergii postlarvae
(Department of Aquaculture, College of Fisheries, Panangad, 1996) Mahesh, S; KAU; Sebastian, M J
The effect of dietary levels of lecithin on growth, survival moulting, FCR and body phospholipid levels of early postlarval freshwater prawn macrobrachium rosen bergii was examined using semi-purified diets in a 56 day feeding experiment. Five casein-egg albumin based semi-purified diets incorporated with 0,2.5,5,7.5 and 10% of purified soy lecithin (60% phosphatidylcholine) were formulated and fed to prawns (ten numbers per treatment) with an initial mean weight of 0.05386g. In order to examine the influence of lecithin at different growth stages of postlarvae the assessment was made every fourteen days during the study period. The result showed that although the overall growth performance was not affected by dietary inclusion of lecithin, SGR% of the prawns fed with the diet containing 2.5% of lecithin showed a significant difference at P<0.01level during the first fourteen days of growth. Similarly the FCR also showed significant variation (P<0.01) between the diets tested in the first and second fortnights (14th and 28th day). In the first fortnight the diets (D1, D2 and D3) produced consistent FCR, while the diets supplemented with higher levels produced higher values. No significant differences (P<0.01) between treatments were detected with regard to survival rate, moulting frequency and body phospholipid levels of the prawns with the termination of the experiment. The prawns moulted once in every night days and no abnormalitied like exuvia entrapment were noticed in any of the experiment animals . Increment of body phospholipids with respect to levels of dietary lecithin suggests a possible replacement of body PL pool with that of dietary PL. The result of the study suggests that supplementation of lecithin at a level of 2.5% in the diet can accelerate growth and improve FCR during the early postlarval phase of Macrobrachium rosenbergii (ie, upto 4 weeks after larval settlement) beyond this, supplementation of lecithin is not needed in the diet. No other deficiency of excess symptoms was detected in the experimental prawns and it is found that lecithin is not responsible for Exuvia Entrapment Disease in Macrobrachium rosenbergii postlarvae.
Open Access
Effect of different diets on growth and survival of angel fish Pterophyllum scalare (Lichtenstein) fry
(Department of Aquaculture, College of Fisheries, Panangad, 1997) Neelakanteswar, A; KAU; Mathew, P M
The effect of different diets on the growth and survival of Angel fish, Pterophyllum sealare (Lichtenstein) larvae was studied. One day old free swimming hatchlings were used in the study for a period of 30 days. The different diets used were Artemia nauplii, Moina micrura, artificial diet, Artemia nauplii + Moina micrura and Artemia nauplii + artificial diet, with four replicates for each treatment. The experiment was repeated twice in order todetermine the consistency of the result. The results showed that the growth of larvae, in terms of gain in length and weight and specific growth rate, was maximum with the mixed diet of live foods. The differences in growth between artificial diet and mixed diet of Artemia nauplii + artificial diet were not consistent. No significant difference was found in the survival rate of larvae fed different diets. O:N ratios showed that the nutritional state of the larvae fed artificial diet was more or less similar to that fed mixed diet of Artemia nauplii + artificial diet, which in turn was comparable with that fed live foods. Thus, the artificial diet has been found to be an effective replacement diet in the larval rearing of Angel fish.
Open Access
Differential growth in the giant freshwater prawn Macrobrachium rosenbergii (De Man) during nursery rearing phase
(Department of Aquaculture, College of Fisheries, Panangad, 1997) Mainuddin, Ahmed; KAU; Thampy, D M
The present study was conducted on freshwater prawn Macrobrachiumrosenbergii (De Man) to find the effect of stocking density and provision of additional substrates in rearing tanks, on differential growth among different size groups of juveniles during early growth phase. The first experiment conducted with various stocking densities ranging from 25 to 800 nos/m2 had revealed that the differential growth and the average size of the post larvae were inversely proportional to the stocking density; however the total biomass production was directly related to the stocking density. The survival rate was not much affected by variation in the stocking density, being almost uniform (87 – 100%) among various treatments. The second experiment has shown that provision of additional substrates could not help to reduce differential growth, rather it enhanced it. However it helped to enhance the average growth, total biomass production and the survival rate. The size grading of juveniles after an initial nursery rearing period of 35 days, into four groups such as small, medium, large and a recombined control group and growing them separately for another 35 days has revealed that the size grading helped in reducing the differential growth and increasing the total biomass production, but could not help to increase the survival rate. It was found that the total biomass production in large size group was about four times higher than that of the small size group and about two times than that of the control group, indicating that growing M. rosenbergii juveniles in grow out systems after size grading and discarding the smaller size group, will be advantageous for increasing production. The male secondary sex character, the appendix masculine was found to appear after 154 days of metamorphosis, when the prawn had reached a size of 6.2 cm and 1.75 g. An allometric pattern of growth was observed in case of appendix masculine wherein a higher ratio of 1:1.34 was recorded in comparison to 1:1.14 of that of the endopod of the second pleopod, in the subsequent moult.
Open Access
Effects of various growth promoters in the diets of macrobrachium rosenbergii post larvae
(Department of Aquaculture, College of Fisheries, Panangad, 1994) Boby Ignatius; KAU; Susheela Jose
The present study was conducted to evaluate the efficiency of various growth promoters on the growth of Macrobrachium rosenbergii post larvae. The various growth promoters tried were antibiotic oxytetracycline, thyroid hormone thyroxine and the enzyme papain. Each growth promoter was incorporated in a casein based purified diet having a protein content of 36%.In the second experiment, the optimum level of growth promoter which showed the best performance in the first experiment was determined. The growth increment of prawns fed on casein based purified diets incorporated with antibiotic oxytetracyc1ine designated as diet T1 was 43.66mg, it was 35.064 mg for diet T2 - containing thyroid, and 32.172 mg for diet T3- containing papain. The growth increment for the control diet was seen to be 26.72 mg. Specific growth rate of the prawns from different treatments ranged from 1.73 to 2.52; with control diet showing the lowest and T1 the highest. Incorporation of the growth promoters in the feed has markedly reduced the food conversion ratio of the animals. Lowest FCR was obtained for the post larvae fed with oxytetracycline, while the highest was for the control, the range being 2.94 to 4.36. The protein efficiency ratio was highest being 0.9770 for the feeds containing oxytetracycline. The PER values for the control diet T0, diet T2 with thyroid, diet T3 with papain were found to be 0.6566, 0.8541 and 0.7576 respectively. Productive protein values were 8.995 for control diet, 13.4763 for diet with oxytetracycline, 11.7710 for diet with thyroid hormone and 10.4266 for diet with papain enzyme. The average survival rate during the experiment was 69.5%. The animals fed on antibiotic incorporated feed gave maximum survival of 72%, while the lowest rate of 66% was observed for thyroxine incorporated feed (T2). Analysis of the data on the various growth parameters in the experiment reveals that the antibiotic oxytetracycline gives better growth amongst the different growth promoters used. In the experiment II, four different levels of oxytetracycline were tested to find out the optimum level. The result of the study showed that, 10 mg/lOOg of feed is the optimum level of oxytetracycline which give maximum growth in Macrobrachium rosenbergii post larvae as indicated by overall growth , specific growth rate, food conversion ratio and protein efficiency ratio.
Open Access
Induced maturation of penaeus indicus using exogenous hormone
(Department of Aquaculture, College of Fisheries, Panangad, 1995) Johnson, D cruz; KAU; Sebastian, M J
The ovarian maturation and spawning of broodstock shrimp play a major role in the development of commercial level seed production of this valuable crustacean. The already proven technology of induced maturation of penaeids in capativity viz. Unilateral Eyestalk Ablation(UESA) has many negative effects which prompted scientists to explore alternative ways of induced maturation like hormone administration. The hormone progesterone alone and in combination with tocopherol were tested for their effectiveness in bringing about ovary maturation and spawning in pond reared penaeus indicus. Progesterone and tocopherol dissolved in ethyl alcohol were injected at three test concentrations of 0.05 ug, 0.10ug and 0.20ug/g body weight . For the preparation of combination test solution the dissolved progesterone and tocopherol were mixed in the ratio of 7:3(V/V). Control shrimps were given alcohol treatment at respective concentrations. The results of the experiment conducted for a period of after 45 days, revealed that the overall survival is not affected (89%) and that progesterone singly or in combination with tocopherol is capable of giving stimulation for ovarian development in P.Indicus Though there was not much observable difference in ovarian development by external viewing, both progesterone alone and in combination with tocopherol at higher dosages have yielded significant GSI difference and ovarian growth, compared with the ethanol treated controls, when the ovaries were dissected out and subjected to detailed study. The percentage somatic growth which was high for control shrimps in contrast to the hormone treated animals have more ovarian growth, suggests an antagonism between these two energy demanding processes. The failure in producing an external visible change in ovarian development, in comparison to eyestalk ablation (ESA) treatment may be due to the existence of the gonad inhibiting hormone (GIH) produced in the eyestalk which would have blocked / suppressed further development of ovary. It is likely that if a GIH inhibitor is also administered along with steroid hormones or tocopherol the stimulus given by them may result in full ovarian development in penaeid shrimp.
Open Access
Cold anaesthetization and live storage of Penaeus monodon Fabricius for transportation in chilled saw dust
(Department of Aquaculture, College of Fisheries, Panangad, 1997) Salin, K R; KAU; Jayasree Vadhyar, K
With a view to standardizing the technology of cold –anesthetization and live storage of adult penaeus monodon in chilled saw dust, three cooling rates of 1.38 + 160C/h within 8 hours (slow cooling rate) 2.76 + 0.320C /h within 4 hours (moderate cooling rate), and 5.52 + 0.640C/h within 2 hours (fast cooling rate) were tested to cold – anesthetize farm raised P.monodon (22.25g) at 15ppt salinity, from 250C to 14+ 10C (fixed on the basis of a pilot study) in plastic net boxes kept in a refrigerated chilling tank of 40 litre capacity, provided with aeration. The cold-anaesthetized shrimps at each cooling rate were packed separately in between two layers (about 3cm thick) of saw dust with 10% moisture and chilled previously at 2-30C, in specially prepared card board boxes (33x22x9cm) lined inside with 12 mm thick Styrofoam sheet. The boxes were kept inside a chilled storage cabinet and maintained at 14 + 10C for a duration of 16-36 hours, and the survival of the shrimps observed at four hourly intervals. The temperature was monitored using a six channel, digital, continuous freezer temperature monitor with a precision of 0.10C. The shrimps cold-anaesthetized at each cooling rate and live stored for each duration were revitalized in aerated circular fibre glass tanks of 80 litre capacity, half-filled with brackish water of salinity 15ppt, and temperature 200 C, which was raised @ 2.70C/h to the ambient temperature of 280C, within 3 hours. The shrimps which showed abnormal behavioural patterns by rolling over into their sides, and remained immobilized upon cold anaesthetization, recovered to active movements after revitalization. Although 100% survival of the packed shrimps was obtained for maximum durations of 24, 20 and 16 hours at the slow, moderate and fast cooling rates respectively, the corresponding statistically valid safe durations for obtaining 100% survival were computed to be 22.9 + 1.09, 19.1 + 0.4 and 14.62 + 1.13 hours, using probit analysis. However, for practical purposes, the durations for obtaining 95% survival were determined as 28.18 + 0.54, 25.7 + 0.54 and 21.88 + 0.71 hours for the slow, moderate and fast cooling rates respectively. Analysis of variance of the percentage survival showed significant difference (P<0.005) among the three cooling rates tested, while pairwise comparison revealed that the slow and moderate cooling rates were identical. This suggested that the moderate cooling rate which took only half the time for cold –anaesthetization of shrimp compared to the slow cooling rate can be considered the optimum, though the choice of the different cooling rates depends on the duration of storage desired. The difference in weight before cold anaesthetization and after revitalization of the live shrimp was studied at 12 and 24 hours of live storage at the three cooling rates, separately which indicated a loss of weight (1.49-8.83%) varying with the cooling rates and durations . However, this was not found to be statistically significant among the cooling rates and durations tested. Sensory evaluation of the cold – treated shrimps was conducted to study the effect of cold-anesthitization and live storage on their appearance and meat quality, at the three cooling rates after 12 and 24 hours of live storage, talking untreated shrimp as control. The body colour of the shrimps turned dark brown and the tips and margins of the pleopods and peraeopods became reddish. There was significant difference (P<0.05) in general appearance, and the colour and flavor of the meat between cold treated and untreated shrimps. However, the texture and odour /aroma of the raw/ cooked meat remained unaffected by cold – treatment. The effect of different cooling rates and the durations tested on the sensory quality of shrimp meat was not significant.

Theses

Browse

Thesis Type

Type

Author

Date

Subject

Search Results