AQUATIC OXYGEN UPTAKE OF THE FRESHWATER FEATHERBACK, NOTOPTERUS CHITALA (HAM.) IN RELATION TO BODY WEIGHT.

The rate of metabolism in fishes is measured by determining the oxygen consumption. The present investigation has been carried out to see oxygen uptake through the gills in relation to body weight in Notopterus chitala at 27.5 ± 1.0oC using continuous water flow system. In Notopterus chitala the oxygen uptake increased from 0.394 to 4.640 mlO h with gradual increase in body weight from 1.166 to 98.750g. the weight specific oxygen uptake decreased from 345.967 to 46.990 mlO2.Kg. h. for the same weight range. The log-log plot of oxygen uptake(mlO h) in relation to body weight gave a straight line with the slope (b) value 0.558. The estimated intercept (a) value was found to be 0.446. The relationship between oxygen uptake and body weight was found to be highly significant. However, the weight specific oxygen uptake decreased by a power of -0.444. Key WordsAquatic oxygen uptake, Body weight, Notopterus chitala. INTRODUCTION Fishes are generally aquatic and require oxygen to meet up theirmetabolic demand. The rate of oxygen consumption in fishes is related to the magnitude of their energy requirement per unit body weight. The relationship between the body weight and the oxygen uptake in detail has been studied by Zeuthen (1947,1953). The oxygen consumption in relation to body weight is specific for different fish species suggested by Moss and Scott (1961) and Beamish (1964). A great deal of work have been done on relationship between oxygen uptake and body weight in some purely aquatic breathing Indian fishes by Roy and Munshi (1984), Kunwar et al., (1989), Ojha and Singh (1981), Singh et © 2020 JETIR October 2020, Volume 7, Issue 10 www.jetir. org (ISSN-2349-5162) JETIR2010265 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir. org 2040 2 2 al., (1991) and Jha et al., (2008), Neelima et al., (2016). The relationship have also been studied in some Indian air-breathing fishes viz, Anabas testudineus (Munshi and Dube ,1973), Colisa fasciatus (Ojha et al., 1977), Channa punctatus (Pandit,2001), Notopterus notopterus (Kumari et al., 2010). Bimodal Oxygen uptake in relation to body weight in Notopterus chitala and Notopterus notopterus have been studied by Ghosh et al., 1986 and kumari et al., 2015 respectively. However, so far no attempt has been made to study the aquatic oxygen uptake in relation to body weight in Notopterus chitala. Therefore, the present work is an endeavour to establish the relationship between the aquatic oxygen uptake and body weight in Notopterus chitala. MATERIALS AND METHODS Live specimens of different weight groups (1.166 to 98.750 g) of Notopterus chitala were collected form river Ganga through fisherman and they were transferred to the large plastic pool of departmental Aquarium House. They were acclimatized for about two weeks feeding live shrimps and pieces of small fish with continuous aerator on. The oxygen consumption through gills was measured by using cylindrical glass respirometer of various capacity depending upon the size of the fish similar to that used by Ghosh and Munshi (1987). The respirometer was connected to large constant level water tank to maintain the water flow under constant hydrostatic pressure. The respirometer was covered over with black cloth to avoid visual disturbance to the fish. The flow of water through the respirometer was adjusted according to the size of the fish to provide stress free condition. The oxygen uptake was determined by the difference in the concentration of dissolved oxygen between inspired and expired water, the rate of water flow and the body weight of the fish using Winkler’s volumetric method (Welch, 1948). RESULTS Aquatic oxygen uptake per unit time (mlO .h ). The oxygen uptake of Notopterus chitala increased from 0.394 to 4.640 mlO . h with gradual increase in body weight from 1.166 to 98.75 (Tab.1). The relationship between oxygen uptake and body weight was found to be highly significant (r=0.962; p<0.001). When the data for the oxygen uptake per unit time where plotted against body weight on log-log graph, it gave a straight line with a slope ‘b’ value of 0.558 and intercept ‘a’ value of 0.446 (Tab.2, fig.2). The rate of oxygen uptake of Notopterus © 2020 JETIR October 2020, Volume 7, Issue 10 www.jetir. org (ISSN-2349-5162) JETIR2010265 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir. org 2041 2 2 chitala have been calculated to be 0.446, 1.612, 5.832 and 21.035 for a 1.0, 10.0, 100.0 and 1000.0 g respectively (Tab.3). The relationship between the oxygen uptake per unit time (mlO .h ) and the body weight may be expressed by the following equation. VO 2 = 0.446. W Figure 1. Experimental setup for the measurement of aquatic oxygen uptake in Notopterus chitala. Aquatic oxygen uptake per unit body weight (mlO2.Kg.h) The weight specific oxygen uptake in Notopterus chitala decreased from 345.967 to 46.99 mlO2.Kg. h. with gradual increase in body weight from 1.166 to 98.750 g. The loglog plot between the body weight and oxygen uptake per unit body weight gave a straight line with a slope ‘b’ value of -0.444 when different scores were fitted by the least square regression method (Tab.2, Fig.2). There is a negative and highly significant correlation between these two variables (r=0.942; p<0.001). The relationship between the weight specific oxygen consumption and body weight may be expressed as follows:VO = 449.086 * W The estimated value of a fish of 1.0, 10.0, 100.0 and 1000.0 g, the oxygen uptake per unit body weight were calculated to be 449.086, 161.661, 58.194 and 20.949 mlO2.Kg. h. respectively. (Tab.3)