Measurements of caloric content of Metapenaeus dobsoni were in<ade

(1) from organic carbon (2) using Karzinkin and Tarkovskaya method and

(3) from proximate composition of body tissues. The results showed that any

one of the three methods could be used with reasonable accuracy. Caloric

content can also be worked out from the carbon values. The conversion factor

for Metapenaeus dobsoni is 1 mg carbon = 14.57 calories

Vijayakumaran, M

Vijayaraghavan, Sumitra

CMFRI Digital Repository

CALORIC CONTENT OF METAPENAEUS DOBSONI SUMITRA VlJAYARAGHAVAN A N D M . VIJAYAKUMARAN Central Marine Fisheries Research Institute, Coc/im-682018. ABSTRACT Measurements of caloric content of Metapenaeus dobsoni were in<ade (1) from organic carbon (2) using Karzinkin and Tarkovskaya method and (3) from proximate composition of body tissues. The results showed that any one of the three methods could be used with reasonable accuracy. Caloric content can also be worked out from the carbon values. The conversion factor for Metapenaeus dobsoni is 1 mg carbon = 14.57 calories. INTRODUCTION The caloric content of the entire animal is an important variable to be determined in energy flow studies, for its knowledge makes it possible to ex-press dry weight in terms of energy units. Hence, much effort has been made earlier to measure the caloric content of the tissues of many organisms (Slo-bodkin and Richman 1961, Paine and Vadas 1969, Cummins and Wuycheck 1971, Snow 1972, Qasim and Jacob 1972, Piatt and Irwin 1973 and Qasim et al 1973). Biochemical constituents of animals are known to vary with seasons, size of the animals, stages of maturity and the availability of food. These in turn aflect the caloric content of the animal. In the present study, an attempt has been made to estimate the caloric content of different size groups of male and female prawns, Metapenaeus dobsoni using three available methods. This was done to evaluate the extent to which the caloric values of this species vary with size and sex. MATERIAL AND METHODS Freshly collected Metapenaeus dobsoni were obtained from the Cochin Backwater and washed with distilled water to remove any adhering material. After washing, the sexes were identified and separated. The total length of each specimen was then measured. In the males the size ranged from 26 mm to 100 mm and in females from 26 mm to 115 mm. Based on the length measure-ments, the prawns were grouped at 5-mm intervals. About 10 to 15 specimens of smaller length groups and 5 of larger length groups were collectively used for the analysis. The different size groups were dried in an oven at 70°C to constant weight. After drying, the samples were homogenised info a fine powder and stored in glass tubes in a desiccator until analysed. CALORIC CONTENT OF M. DOBSONl 121 Total carbohydrate was estimated by the method of Dubois et al (1955) and lipid content by the methanol-chloroform method (see Raymont et al 1964). For the total protein estimation, a known quantity of the sample was first dissolved in 0.5 ml of 40% NaOH solution and then made up to a known volume. From this, subsamples were drawn and treated with biuret reagent. Wakeel and Riley's (1957) method was followed for the determination of organic carbon. The caloric values of the samples were estimated by the method of Karzinkin and Tarkovskaya (1964). The caloric values were also calculated from the biochemical components (major metabolites) using the following con-version factors: 4.2 cal mg-1 for carbohydrate, 4.19 for protein and 0.5 for lipid (Prosser and Brown, 1961). For each estimation triplicate analyses were carried out and the values were averaged. RESULTS The values for carbohydrate, lipid, total protein, organic carbon and caloric contents are given in Table 1. The variations in the percentages of car-bon between the two sexes were found to be non-significant at 5% level (Value = 1.036). Table 2 gives the caloric values determined by the three different methods (1) Karzinkin and Tarkovskaya method (2) calculated from the pro-ximate composition and (3) caloric values calculated from the simple regression using the percentages of carbon and measured caloric values. The caloric con-tent (measured) and that computed from the biochemical constituents in the two sexes were also found to be non-significant at 5% level (values = 0.0054 and 0.132 respectively). Table 2 also includes the ratio of calories to carbon values. The relative effectiveness of each method was determined by calculating the correlation coefficient (Table 3), which were found to be non-significant. This probably indicates that any of the three methods can be applied with reasonable accuracy. DISCUSSION Qasim and Jacob (1972) converted the values of organic carbon of different species of fishes into energy units using the equation of Piatt et al (1969). Subsequently, Qasim et al (1973) have pointed out the limitation in estimating the energy units by applying such an indirect method which was initially determined for zooplankton. Recently, Piatt and Irwin (1973) have indicated that the percentage of carbon in dry tissues is a good indicator of its caloric value and for dried phytoplankton they gave the following equation: cal mg dry wt—'= 0.632 + 0.086 (% C). A similar equation can be worked out for Adf. dobsoru using the carbon values. This was fQund to be 3.7334 + 0.0244 (% C) for males and 1.1598 + 0.1067.(% C) for females. The,.standard error from flie estimated equations were 0.0289 and 0.0456 respectively. 122 VIJAYARAGHAVAN AND VIJAYAKUMARAN TABLE 1. Biochemical values of Metapenaeus dobsoni. 3 26-30 31-35 36-40 41-45 46-50 51-55 56-60 61-65 66-70 71-75 76-80 81-85 86-90 91-95 96-100 101-105 106-110 111-115 1 M F M F M F M F M F M F M F M F M F M F M F M F M F M F M F F F F •fl-O 3.51 3.41 3.55 3.65 3.79 2.94 4.03 3.80 3.13 3.95 3.65 3.24 3.66 3.39 3.81 3.43 2.71 3.67 2.51 2.65 2.88 3.11 2.75 3.38 3.38 3.15 4.14 — 3.25 — 3.63 3.08 3.74 '3 8.65 8.65 7.30 8.13 6.26 8.32 8.90 7.50 6.65 7.53 6.62 6.74 8.19 7.68 14.67 8.41 9.71 6.72 7.59 12.20 11.68 11.64 7.82 7.64 6.28 12.56 17.10 — 12.92 — 12.11 15.05 15.89 _g 66.00 66.00 62.00 69.00 80.00 73.00 83.00 75.50 83.00 72.00 82.50 83.00 79.00 73.50 72.00 83.00 83.00 77.50 60.00 78.70 79.00 49.00 86.00 77.00 79.00 72.50 68.00 — 83.00 — 68.00 68.00 66.00 24.00 35.10 32.80 32.30 28.70 29.00 29.10 29.30 29.70 31.20 31.30 29.00 29.30 31.70 29.00 30.30 32.90 28.40 35.40 33.00 21.60 38.90 29.50 39.90 37.70 33.40 31.50 — 39.70 37.80 33.20 42.10 34.30 3.921 4.059 4.151 4.146 5.267 3.680 3.565 4.853 6.187 3.565 5.704 4.381 3.657 4.381 3.956 4.025 3.599 4.025 4.266 4.349 4.473 4.899 3.473 4.704 4.427 6.055 5.609 — 4.981 5.624 4.358 5.658 6.267 CALORIC CONTENT OF M. DOBSONl 123 TABLE 2. .a 1 26-30 31-35 36-40 41-45 46-50 51-55 56-60 61-65 66-70 71-75 76-80 81-85 86-90 91-95 96-100 101-105 106-110 111-115 X M F M F M F M F M F M F M F M F M F M F M F M F M F M F M F F F F Comparison of measured values of Metapenaeus h 3.921 4.059 4.151 4.146 5.267 3.680 3.565 4.853 6.187 3.565 5.704 4.381 3.657 4.071 3.956 4.025 3.599 4.025 4.266 4.349 4.473 4.899 3.473 4.704 4.427 6.055 5.669 5.428 4.981 5.624 4.358 5.658 6.267 en tJ u 8 Ml 8 1 | 3.695 3.610 3.441 3.816 4.106 3.972 4.493 4.037 4.241 3.898 4.239 4.255 4.240 3.952 4.573 4.421 4.514 4.039 3.340 4.560 4.834 3.285 4.442 4.094 4.049 4.367 4.648 — 4.850 — 4.151 4.408 4.433 and calculated 1 dobsoni. 4.319 4.977 4.534 4.612 4.434 3.819 4.444 4.222 4.458 4.469 4.497 3.819 4.449 4.534 4,441 4.352 4.536 4.104 4.597 4.731 4.261 4.169 4.453 4.821 4.654 4.756 4.502 5.265 4.702 5.356 4.730 5.889 4.873 caloric TJ 16.34 11.56 12.66 12.84 18.35 12.69 12.25 16.56 20.84 11.43 18.23 15.11 12.48 12.84 13.64 13.28 10.94 14.17 12.05 13.18 20.71 16.95 11.77 13.88 11.74 18.13 18.00 14.63 12.84 14.88 13.13 13.44 18.27 124 VIJAYARAGHAVAN AND VIJAYAKUMARAN TABLE 3. Correlation coefficients using the three methods. (I. Karzinkin and Tarkovskaya method, II. Calculated from the proximate composition and III. Calculated from the simple regres-sion using % of carbon and measured caloric values.) Method I Method II Method III Method I 0.0109 0.1635 Method II -0.0435 A comparison of the caloric content per unit carbon for some of the organisms for which data are available has been made in Table 4. From the Table 4, it is evident that the values obtained in the present study come closer to that recorded by Piatt and Subba Rao (1970). Piatt and Irwin (1973) pointed out that their values are lower as compared to that of Piatt and Subba Rao (1970). The difference in the values was attributed to the wet oxidation method. However, some of the values of Qasim et al (1973) agree well with those of the present study and also of Piatt and Subba Rao (1970), while a few are lower than those recorded by Piatt and Irwin for phytoplankton. Qasim et al (1973) estimated the caloric values of food and body of several species of fishes and prawns (1) from organic carbon (2) using Kar-zinkin and Tarkovskaya method and (3) by bomb calorimetry. They pointed out that any of the three methods is reliable despite the fact that there were some limitations inherent in each method. However, they did not take into TABLE 4. The absolute values of caloric content per unit carbon in different species of organisms. Species Phytoplankton Phytoplankton Sardi?iella longiceps EtroplUs suratensis Thryssa malabarica Thryssa purava Thryssa mystax Nemipterus japonicus Metapeiiaeus monoceros Metapenaeus dobsoni cal|mg C measured 15.71 11.40 14.05 ^ 9.06 14.07 16.63 11.89 8.53 11.70 14.57 Reference Piatt and Subba Rao (1970) Piatt and Irwin (1973) y Qasim et al (1973) Present work CALORIC CONTENT OF M. DOBSONI 125 consideration the major metabolites (carbohydrate, lipid and protein), which are very important in the estimations of caloric value (Paine and Vadas, 1969). The inclusion of major metabolites in the present study further indicates that any of the three methods can be used with success. However, from the practical consideration, it is easier to determine carbon content which is easier than un-dertaking detailed laboratory analysis (Platt and Irwin, 1973). For M. dobsoni 1 mg C = 14.57 calories. This could be used as a simple conversion factor for this species. It will be of interest to know how far this relationship would vary in other prawns. Similar data on other species are needed for working out the energetics of tropical ecosystems. ACKNOWLEDGEMENT The authors wish to express their deep sense of gratitude to Dr S. Z. Qasim, Director, Central Marine Fisheries Research Institute, Cochin, for his critical reading of the manuscript and unfailing guidance. We are grateful to Mr A. K. Kesavan Nair for his help in statistics. Our thanks are due to Mr K. H. Mohamed and Dr P. Vedavyasa Rao for valuable discussions. REFERENCES CUMMINS, K . W. AND J. C. WUYCHECK. 1971. Caloric equivalents for investigations in ecological energetics. Mitt. Int. Ver. Theor. Angew. Limnol., 18: 158 p. DUBOIS, M. , K. A. GILLS, J. K. HAMILTON, P. A. REBERS AND P. SMITH. 1955. Calori-metrdc method for determination of sugars and related substances. Anal. Chem., 28: 350-356. KARZINKIN, G . S. AND O . I. TARKOVSKAYA. 1964. Determination of caloric value of small samples. In: Techniques, for the investigation of fish physiology, 122-124. E. N. Pavloski (Ed.), Israel Programme for Scientific Translation. PAINE, R. J. AND R. L. VADAS. 1969. Caloric values of benthic marine algae and their postulated relation to invertebrate food preference. Mar. Biol., 4: 79-86. PLATT, T., V. M. BRAWN AND B. IRWIN. 1969. Caloric and carbon equivalents of zoo-plankton bdomass. / . Fish. Res. Bd. Canada, 26: 2345-2349. PLATT, T . AND B. IRWIN. 1973. Caloric content of phytoplankton. Limnol. Oceanogr., 18: 306-309. PLATT, T. AND D . V. SUBBA RAO. 1970. Primary production measurement on a natural plankton bloom. J. Fish. Res. Bd. Canada, 27: 887-899. PROSSER, C . L. AND F . A . BROWN. 1961. Comparative animal physiology, 2nd ed. Saunders. QASIM, S. Z. AND P. G . JACOB. 1972. The estimation of organic carbon in the stomach content of some marine fishes. Indian J. Fish., 19: 29-34. QASIM, S. Z., V. SUMITRA AND D . C. V. EASTERSON. 1973. Caloric values of the in-gested food of some marine fishes and prawns. Indian J. Fish., 20 (2): 318-325. 126 VIJAYARAGHAVAN AND VIJAYAKUMARAN RAYMONT, J. E. G., J. AUSTIN AND E . LINFORD. 1964. Biochemical studies on maxine zooplanfcton. I. The biochemical composition of Neomysis integr. J. Cons. Int. Explor. Mer., 28: 354-363. SLOBODKIN, L . B. AND S. RICHMAN. 1961. Calories|gm in species of animals. Nature, Lond., 191: 299. SNOW, N . B. 1972. The effect of season and animal size on the caloric content of Daphnia pulicaria Forbes. Limnol. Oceanogr., 17: 909-913. WAKEEL, S. K. E L . AND J. P. RILEY. 1957. The determination of organic carbon in marine muds. /. Cons. per. int. Explor. Mer., 22: 180-183. 

Caloric content of Metapenaeus dobsoni

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Caloric content of Metapenaeus dobsoni

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