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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
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
Commercial probiotics in tank reared nursery phase of freshwater prawn,Macrobrachium rosenbergii (De man, 1879)
(Department of Aquaculture, College of Fisheries, Panangad, 2005) Beryl, E B; KAU; Mohanakumaran Nair, C
The efficacy of two commercial probiotics, Waves and Epicin on the growth and survival of M. rosenbergii PL and on the chemical and biological characteristics of water and soil were studied. The experimental set up consisted of fiberglass tanks of 70 l capacity with two treatments and a control, each with 5 replicates. Soil from a fishpond was filled to a height of 5 cm and water filled to a height of 25 cm. The post larvae were stocked @ 500 no/m2 and mild aeration provided. Commercial freshwater prawn feed starter 1 (Higashi) was given @ 100% of body weight. Analysis before the introduction of probiotics showed the presence of microorganisms such as E. coli, Salmonella, Hafnia alvei, Faecal Streptococci, Aeromonas caviae, A. sobria, A. hydrophila and Enterobacter aerogenus in the water and soil. Enterobacteria such as Enterobacter aerogenus, Hafnia alvei, Aeromonas sobria and A. hydrophila were present in the PL. The probiotics Waves and Epicin were added @ 0.5 ppm and 0.25 ppm respectively to the experimental tanks once in ten days and the microbiological observations and water quality parameters were studied once in 15 days. The introduction of the probiotics increased the growth and survival and reduced the F.C.R. of M. rosenbergii in nursery system. The species composition of the bacteria in the soil, water and body of the animal were not affected by treatment with probiotics, other than that the E. coli present originally and continued in the control was not detected in the tanks treated with probiotics. The T.P.C. was also less in the treatments compared to the control. Probiotics considerably reduced the level of NH3-N in culture tanks. Epicin was found to have reduced the NH3-N level effectively than the Waves.
Open Access
Cryopreservation of spermatozoa of critically endangered yellow catfish Horabagrus Nigricollaris (Pethiyagoda & Kottelat 1994)
(Department of Aquaculture, College of Fisheries, Panangad, 2007) Rajani Vadthya; KAU; Dinesh, K
In order to develop gene banking techniques aimed at conserving the critically endangered black collared yellow catfish of the Western Ghats, Horabagrus nigricollaris and popularize this species in the aquaculture scenario a study on cryopreservation of spermatozoa was undertaken. Freshly collected milt was observed for its characteristics. Well water was used to activate the milt in various stages of the experiment. There was no significant difference in motility of spermatozoa or percentage hatching from fresh and milt cryopreserved using 10% dimethyl sulfoxide (DMSO). Screening of four extenders (A, B, C and D) containing NaCl, KCl, CaCl2, NaHCO3, KH2PO4, MgSO4.7H2O, Na2H PO4 and Glucose at various proportions clearly indicated that the extender composition had significant effect on the percentage of motility, fertilization and hatching. Selected milt samples were preserved under cryogenic condition and utilized for experimental spawn production. The quality of milt samples was analyzed for the spermatocrit value, sperm density, pH, motility score and time: values obtained ranged from 57.8 to 59.8%; 16.5 x 109 to 20.9 x 109 spermatozoa/ ml of milt; 7.2 to 7.4; 4+ to 5+ (i.e. 80-100%) and 30 to 70 seconds respectively. The most promising combination was extender - A with 10% DMSO as the cryoprotectant. The ratio of milt and diluent was 1:4. Samples were equilibrated at 0°C ± 4°C on ice and vapourised over liquid nitrogen fumes for 10 minutes and finally stored in liquid nitrogen for three months. Stored milt samples were thawed and utilized to fertilize the eggs. Quick thawing procedure (27°C ± 2°C for 7 seconds) was followed. A French straw containing 0.5ml milt was found to be sufficient to fertilize 200 eggs approximately. Average fertilization % obtained was 30.3 ± 2.8 for extender- A against 35.8± 0.4 for the control. Mean hatching % obtained was 35.0 ± 4.7 for extender - A and 41.6± 4.4 for the control. No significant difference in fertilization success was found between cryopreserved sperm and untreated sperm from the same milt samples. Viable hatchlings were produced from milt that had been cryopreserved for three months indicating the feasibility of establishing a cryopreservation protocol to bank the genes and popularize the aquaculture of this critically endangered species. With the rapid global expansion of aquaculture, there is a need for year-round availability of larvae that could, to some extent, be met through cryopreservation of gametes.
Open Access
Utilization of water spinach Ipomoea aquatica leaf meal as protein source in the feed of Macrobrachium rosenbergii post larvae
(Department of Aquaculture, College of Fisheries, Panangad, 2007) Sijimol, A P; KAU; Thresiamma James
The present study aimed to find out the feasibility of using water spinach leaves as a low cost plant protein source and dietary evaluation of the formulated diet through growth trials employing post larvae of Macrobrachium rosenbergii, thus to determine the optimum level of substitution of spinach leaf meal. The experiment was done for a period of 60 days. A comparison has also been made between the diets having various levels of inclusion of water spinach leaf meal over the control diet without spinach leaf meal. Five isonitrogenous test diets T1 to T5 were prepared with 30% crude protein. The feed ingredients used were clam meat, Ipomoea aquatica leaf meal, wheat bran, ground nut oil cake, tapioca flour, vitamin mineral mixture and sunflower oil. The control diet T1 was prepared by using all ingredients mentioned above, without Ipomoea leaf meal. The test diets T2, T3, T4 and T5 were prepared by using all ingredients mentioned above and replacing clam meat with water spinach leaf meal at inclusion levels of 12 %, 24 % 36 % and 48 % respectively. Results showed better growth rates in prawn post larvae fed with diets (T2) containing 12% Ipomoea leaf meal. Among the test diets, T2 recorded highest growth rate (603.63 mg). Specific growth rate, food conversion ratio and protein efficiency ratio also showed better performance of prawn post larvae fed on test diet with 12% inclusion of spinach leaf meal. The highest SGR (3.67) and PER (2.99) were recorded in prawns fed on diet T2 and lowest SGR (2.68) and PER (1.48) were obtained with diet T5. The survival rate of post larval prawns were not found to be significantly influenced by the various test diets used and the survival ranged from 77.5% to 82.5%.
Open Access
Effect of eyestalk ablation on the rematuration of female macrobrachium rosenbergii (De Man) in captivity
(Department of Aquaculture, College of Fisheries, Panangad, 2003) Vadher Kailashkumar Hirabhai; KAU; Aneykutty, Joseph
The giant freshwater prawn, Macrobrachium rosenbergii is one of the commercially important spccces widely cultured throughout the tropics, subtropics and some parts of the temperate region. Non- availability of brood stock in sufficient numbers at appropriate time has been the greatest constraint for successful operations of prawn hatcheries. To avoid entire dependence on natural sources, development of brood stock of female prawns in captivity is essential. The objectives of the present study were to find out the role of eyestalk ablation on rematuration of spent female of M. rosenbergii in captive conditions and to study the histology of the ovary during rematuration of eyestalk ablated and unablated spent female of M. rosenbergii. In the rematuration experiment the effect of eyestalk ablation on moulting frequency, spawning frequency, larval hatch fecundity, incubation period, ovarian development and ovarian index of spent female of M. rosenbergii was evaluated for 60 days. The histology of ovary in M. rosenbergii during rematuration was also studied. The analysis of the result was done with student's t-test and paired t- test. A significant difference was observed in moulting frequency and spawning frequency of ablated and 'unablated spent female of M. rosenbergii. Larval hatch fecundity of ablated and unablated spent female of M. rosenbergii was not found to vary significantly. Significant difference was found in larval hatch fecundity after first time and second time hatching of both ablated and un ablated individuals. The incubation period was not found to vary significantly among ablated and unablated. However, slight reduction in incubation period was observed in ablated ones. Five histological stages of ovaries viz. previtellogenic stage, early vitellogenic, vitellogenic and late vitellogenic and matured oocytes were observed. In the histological sections of the ovaries, starting from spent ovary to the ripe ovary at weekly interval, similar type of oocyte development stages were observed in both ablated and unablated. IIowever, the size of largest oocyte in ablated was slightly higher than the size of oocyte in unablated at each week of development. It was observed in the present study that ovarian index of ablated spent female was higher than unablated at each week of development. The rematuration experiment has shown that eyestalk ablation significantly enhanced moulting frequency and spawning frequency but the effect was insignificant in terms of larval hatch fecundity and incubation period in spent female of M. rosenbergii. Insignificant increase in ovarian development and ovarian index were also observed in ablated spent female of M. rosenbergii.
Open Access
Biomodulation of non-specific immune response in the tiger shrimp Penaeus monodon fabricus with spirulina iccorporated diet
(Department of Aquaculture, College of Fisheries, Panangad, 2002) Jadhav vishal Shripatrao; KAU; Devika, Pillai
Black tiger shrimp; Penaeus monodon is an important species cultured all over the world. However, disease outbreaks have caused senous economic losses in several countries. For successful farming of shrimps disease prevention is a prime necessity The present study was designed to assess the immunostimulating potential of Spirulina and to see its effect on growth as well as colour of P. monodon juveniles. In this study, juveniles of P. monodon were used for evaluating the effect of different levels of Spirulina on growth, food conversion ratio, food conversion efficiency, survival as well as prophylactic potency of Spirulina evaluated by proPhenoloxidase activity, antibacterial assay, haemagglutinin assay, phagocytosis and challenge study Effect of Spirulina on colour of shrimps was also studied. Five experimental diets designed as T I to T 5 were prepared by using clam meat, Spirulina, rice bran, cod liver oil and vitamin- mineral mix. The total protein content of all diets were kept near to 40% and Spirulina was incorporated at 0%, 10%, 20%, 30% and 40% in diets by replacing clam meat. Completely randomized design with five treatments each having four replications was used for analyzing the results. In each tank ten numbers of Penaeus monodon juveniles were kept. Feeding was done for a period of 35 days. The test animals fed with diet containing Spirulina up to 30% incorporation showed better growth, food conversion ratio and food conversion efficiency. But survival during experiment was not affected by the addition of Spirulina. Spirulina incorporated treatments showed higher phenoloxidase activity than control. Antibacterial activity was also observed in the treatments incorporated with Spirulina, while in control no antibacterial activity was observed. Result of agglutinin activity was not 99 clear as control also showed agglutination in undiluted haemolymph sample and partial agglutination in 1:2 dilution of haemolymph. Spirulina incorporated treatments showed agglutination up to 1:4 dilution of haemolymph. But in 1:4 dilution only partial agglutination was observed. Increased adherence of haemocyte to yeast cells was observed indicating higher phagocytic activity in the treatment incorporated with Spirulina, while adherence of haemocyte was rarely observed in control. On challenge with Vibrio parahaemolyticus, shrimps treated with Spirulina incorporated diet showed delayed mortality as compared to control. Spirulina treated shrimps showed darker colouration than control.

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