Studies on the Survival and Growth of Fry of Catla catla ( Hamilton , 1922 ) Using Live Feed

Effect of live feed on the survival and growth of fry of Catla catla using three different live feeds namely, Cyclopoid (Thermocyclops decipiens), Cladoceran (Moina micrura), and mixed diet (Cyclopoid and Cladoceran) were studied. Commercial feed (Sunder’s feed) was used as control. Feeding experiments were carried out in 100 L tanks for 40 days. Fish fry fed with the mixed diet showed significantly better survival rate (54.80± 2.43%) than those fed with other food types (P < 0.001). Fish fry fed with Cyclopoid had significantly (P < 0.001) better growth (26.03± 1.88mm, weight 61.07± 3.53mg) than those fed with other food types. Biochemical studies showed higher level of protein, carbohydrate, and lipid content inCatla fry fed with Cyclopoid diet.The results are discussed in the light of the literature available. It could be suggested that the Cyclopoid diet can be used as live feed for effective production of Catla fry.


Introduction
Availability of live food organisms in sufficient quantities is a major factor in the cultivation of early stages of shellfish and finfish.Only a few live feed organisms have been used in hatcheries [1].In aquaculture, an increasing demand exists for live zooplankton in spite of the availability of Artemia nauplii and rotifers [2][3][4].The zooplankton forms ideal food usually in the larval stages of prawns and in early larval stages of fishes [5].Zooplankton are the preferred food of fishes, particularly, fry and fingerling stage [6].Being a natural food of fish and prawn larvae, zooplankton collected from natural resources are used as diet for the larvae of ornamental fish in many hatcheries [7].
Zooplankton have been widely used for rearing fish larval stages, and most studies indicated that the fry performed better when fed live zooplankton than dry artificial diets [8,9].In larviculture, artificial diet may perform poorly due to poor digestibility and deficiency of growth factors [10].Common carp and Atlantic salmon grew faster when fed on zooplankton than those fed on formulated diets [11].Many authors have emphasized zooplankton as live food in general, particularly, Copepods and Cladoceran [12][13][14][15][16]. Nutritional quality of Copepods is reported to have high protein content and a good amino acid profile.The fatty acid composition with regard to HUFA is high in Copepods [17].Zooplankton growth in nature may depend on the quality of the food available as the phytoplankton community changes.Phytoplankton may stimulate zooplankton development by production of vitamin E (-tocopherol) and releasing "odour" into water [18].Feeding rates of zooplankton are mainly dependent on food concentration, food quality, and water temperature [19,20].It has been shown by several workers that feeding among Copepods was related to chemoreceptors [21,22], mechanoreceptors [23] and taste of the particular food [24].
The Cladocerans are considered to be suitable live feed for fish larvae and they were mass cultured successfully by many investigators, using different cheap organic waste products [9,[25][26][27].Daphnia are small freshwater Cladoceran crustaceans commonly called "water fleas." This common name is the result of not only their size but also their short, jerky, and hopping movement in water.The genera Daphnia and Moina are closely related.
Moina is a common and widely distributed freshwater cladoceran.Adult Moina are longer than newly hatched brine shrimp and approximately two to three times the length of adult rotifers.However, young Monia are approximately the same size as or only slightly larger than adult rotifers and smaller than newly hatched brine shrimp.In addition, brine shrimp die quickly in fresh water.As a result, Moina are ideally suited for feeding freshwater fish fry.Newly hatched fry of most freshwater fish species can ingest young Moina as their initial food [28].
Copepods are microscopic zooplankton inhabiting both fresh water and marine environment.They include free living orders: Calanoida, Cyclopoida, and Harpacticoid.Of these three, Calanoids and Cyclopoids are more dominant than Harparcticoids (Alfred et al., 1973).Copepods are the most important components of aquatic ecosystem and play vital role as primary consumers.This group directly transfers energy from primary producers to secondary consumers.They range in size from less than 1 mm to more than 5 mm.In the aquatic habitat, their small size is compensated by their occurrence in large numbers [29].Copepods are the dominant and most abundant secondary producers among marine and fresh water zooplankton and hence are of major ecological significance [30].They are an excellent food of high nutritional value for zooplanktivorous fish and shrimps [31].
Copepods constitute an important component of the food chain in aquatic systems.The nutritional quality of Copepods is accepted to be highly satisfactory for larvae of prawn and finfish species.Biochemical studies have shown that Copepods are rich in proteins, lipids, essential amino acids (EAAs), and essential fatty acids (EFAs), which can provide enhanced reproduction of brood stock, augmented growth, immune stimulation, and color enhancement in prawns and fishes [13,16].Copepods show wide occurrence from wild sources throughout the year [32,33].However, fluctuations in quality and quantity and drawbacks of collecting methods are major problems for their commercial utilization.In view of the growing needs for the production of large quantities of larval shrimp and fish for aquacultural practices, the culture of Copepods has been attempted [31].Copepods constitute important live food in the rearing of larvae of fishes [34,35].Many authors have reported the utilization of Copepods from wild and cultured sources for higher yields of prawns in ponds [36][37][38].Cyclopoid Copepods are physically diminutive, yet their presence in aquatic system can be great.Cyclopoids usually range in length from 0.5 to 2.0 mm and are primarily benthic, although a few species thrive in the pelagic zones of lakes, seas, and oceans.Within these larger bodies of water, Cyclopoid biodiversity tends to be the highest in the littoral zone.Their diversity and abundance can also be great in shallower bodies of water, such as wetlands and temporary ponds [39].Some species are euryhaline and occur in brackish water and fresh water [40].Cyclopoid copepod plays an important role in aquatic food webs as either primary consumers or predators.They can also be an important source of food for larval, juvenile, and adult fish of many species.
The aim of the present study was to evaluate the effect of three different live feed organisms such as Cyclopoid (T.decipiens), Cladocerans (M.micrura), and mixed diet (Cyclopoid and Cladoceran) on the survival, growth, and the biochemical composition of the fry of Catla catla.

Materials and Methods
Fry of Catla was obtained from Tamil Nadu Fisheries Department Seed Farm at Bhavanisagar, Tamil Nadu, in May 2011 and were maintained in the laboratory for further studies.For fry rearing and feeding experiments, freshly hatched out early fry stages (average length 6.10 ± 0.10 mm and average weight: 10.37 ± 0.25 mg) were carefully selected.Fry rearing and feeding experiments on C. catla were conducted with different feeds.Artificial pelletized commercial feed (Saunders's feed with proximate composition of protein 60%, lipid 20%, carbohydrate 10%, ash 8%, and moisture 5%) served as control feed.The Cladoceran, M. micrura, and the copepod, T. decipiens, were fed separately as well as in the form of mixed feed (50% M. micrura and 50% T. decipiens) which constitutes an experimental diet.A batch of 250 early fry of C. catla of similar length were introduced in the cement experimental tank (75 cm (length) × 40 cm (diameter) in 35 liters of water) for control as well as experimental diet.The experiments were repeated to obtain triplicate values.The fry of C. catla commenced their exogenous feeding on the 4th and 5th day, respectively.Food was offered to the different batches of Catla fry at the rate of 30% of their body weight in a similar schedule of 3 times a day (7 am, 2 pm, and 6 pm) and experiments were conducted for 40 days.During the course of experiment, increased feed was offered as per the following formula [9]: Feed increase = average body wt.
× approximate survival × % of body wt. ( During experimental period, water temperature and pH were recorded daily and were found in normal range (26 ± 1 ∘ C and pH 6.8-7.1).Other physicochemical parameters such as dissolved oxygen, calcium, magnesium, total hardness, alkalinity, ammonia, nitrite, nitrate, phosphate, sulphate, and chloride were analyzed on stocking day, 8th, 16th, 24th, 32nd, and 40th day following the procedures of APHA (1998) and IAAB (1998).Daily at morning hours, excess feed and fecal matter were removed from the fry rearing tank and 50% of water was replenished.Except during water exchange and feeding time, the fry rearing tank was continuously aerated.Length and weight of the fry from all tanks were recorded every day for 12 days and then on the 17th, 24th, 31st, 37th, and 40th day of experiments.Survivals of fry of both the fishes were calculated on the 8th, 16th, 24th, 32nd, and 40th day.Percentage survival (%) was calculated (dead fishes were removed).At the end of the experiments, analysis of bodyhomogenate of the fry of Catla was carried out for protein [41], carbohydrate 6 [42], and lipid [43].
Mean and standard deviation were calculated for length and weight, body weight gain, survival, and SGR (specific where   is final weight,   is initial weight, and  is time (number of days).

Results
Overall growth parameters of Catla fry fed with different feeding regimes are shown in  1).SGR values of Catla fry were higher in Cyclopoid diet (0.13), followed by mixed diet (0.09), in Cladoceran diet (0.08) and in control (0.03).It is clear that Cyclopoid diet showed higher SGR in Catla fry followed by mixed diet.However, the highest survival rate of Catla fry after 40 days was recorded in mixed diet (54.8%), followed by Cladoceran diet (49.33%) and Cyclopoid diet (43.33%) when compared to that of control diet (36.67%) (Table 2).Statistical analysis revealed that the effects of 3 diets on length and weight of Catla fry are significantly different ( < 0.001).
The biochemical parameters of fry of Catla fed with different feeding regimes are given in Figure 1.It is evident that the carcass composition of Catla fry showed highest protein, carbohydrate, and lipid levels in Cyclopoid diet followed by mixed diet and least in Cladoceran diet.Protein level in the fry of Catla was 4.00 ± 0.15 mg/gm in Cyclopoid diet followed by mixed diet (4.00 ± 0.10 mg/gm).In Cladoceran diet, it was 3.69 ± 0.12 mg/gm compared to 2.817 ± 0.10 mg/gm in control diet.With respect to carbohydrate, the highest levels were obtained in control diet (0.94 ± 0.03 mg/gm) and Cyclopoid diet (0.90 ± 0.03 mg/gm).In the fry fed Cladoceran diet, the carbohydrate content was 0.84 ± 0.02 mg/gm, whereas, in the mixed diet, it was 0.82 ± 0.02 mg/gm.Lipid composition of Catla fry was the highest in   Cyclopoid diet (0.16 ± 0.00 mg/gm).In the fry fed with mixed diet and Cladoceran diet, it was 0.14 ± 0.01 mg/gm, whereas, in the control diet, it was 0.12 ± 0.06 mg/gm.
Chemical parameters of the water samples of Catla fry rearing tanks are shown in Tables 3 and 4. The dissolved oxygen content in the fish fry rearing tank with Cyclopoid diet ranged between 3.98 and 4.90 mg/L.As shown in Table 3, the calcium content of the water sample showed gradual increase and attained maximum level (48 mg/L) on the 40th day of experiment with control diet and the Cyclopoid diet showed the maximum (41.00 mg/L).All other chemical parameters (magnesium, total hardness, alkalinity, ammonia, nitrite, nitrate, phosphate, sulphate, and chloride) showed a narrow fluctuation during the period of experimentation.The chemical parameters of the fry rearing tank with Cladoceran diet occurred in normal range and the values did not vary widely during the different period of the experiment.In the fry rearing tank with Cyclopoid and Cladoceran diet, the dissolved oxygen showed narrow fluctuation during the course of experimentation.All other parameters showed a very narrow range of fluctuation.
Pearson correlation matrix showed weak correlation coefficient value "r" for most of the parameters in Catla fry rearing tank.However, high positive correlation ( = 0.704) was recorded between phosphate and chloride, sulphate and chloride ( = 0.673), and calcium and chloride ( = 0.539).Ammonia and nitrite showed a moderate positive correlation ( = 0.440).
Correlation between dissolved oxygen and survival of Catla fry had a positive correlation ( = 0.063).Similarly, positive correlation was obtained between the level of magnesium and survival of Catla fry ( = 0.386).Negative correlation between sulphate and survival was observed ( = −0.741)and nitrate and Catla fry survival was recorded ( = −0.410)(Table 5).All other water quality chemical parameters and survival rate showed negative correlation.

Discussion
In intensive rearing of fish larvae, feeding constitutes the major factor, since fish obtain their entire nutritional requirement through the food consumed [45].Various studies highlight the fact that fish and prawn larvae prefer live feed compared to formulated feed [46][47][48].Nutritional of live feed further enhanced by 7 bioenrichment and therefore the nutritional status of fishes and prawn can be increased.In the present study, it is clearly evident that Catla fry showed significant increase in growth parameters, survival, SGR, FCR, and protein, when fed with live feed like Cyclopoid singly or combination of Cyclopoid and Cladoceran which is in agreement with the previous reports [47,49].It is possible that growth increment seen in Catla fry in the present study could be due to high protein content and amino acid profile of live feed organism reported earlier [47].In the present study, it was demonstrated that both control feed (artificial pellets) and live feeds were accepted by the fry of both the fishes as evidenced by their development of late fry stage.These diets supported varying degrees of growth and survival of the fish fry in a forty-day fry rearing experiment.Further, results of present study suggest that fry rearing up to late fry stage is better with live feed than the control (artificial pellets) as evidenced by the higher growth and survival of the fry of Catla.
With regard to the chemical parameters of the culture system, higher dissolved oxygen content was recorded in the rearing system of Catla fry with Cladoceran as the live feed.Dissolved oxygen levels are improved due to photosynthesis, while ammonia levels are reduced through assimilation by phytoplankton.Different levels of dissolved oxygen content were reported in fish rearing system of larvae of Cyprinus carpio (8.77 mg/L to 10.85 mg/L) [49].Generally, cyprinids are capable of tolerating low oxygen levels of 3 mg/L [50].The level of dissolved oxygen content in the Catla fry rearing system of present study was found between 3.9 mg/L and 5.3 mg/L.This level of dissolved oxygen is adequate to promote normal growth and development [51].It is interesting to note that with similar intensity and duration of aeration, lower dissolved oxygen content in the koi carp tanks might be due to their higher oxygen consumption which is indicative of higher metabolism in the larvae of koi carp than the goldfish [9].
Temperature is one of the important parameters, which has a definitive influence on the growth and duration of larval period of carps.In the present study, even though better development of Catla fry was recorded in a temperature range of 30 ± 2 ∘ C to 32 ± 1 ∘ C, Jhingran (1991) observed that carps thrive well in the temperature range of 18.3 ∘ C to 37.8 ∘ C [51].Temperature is also suggested to be optimum for the larval development of freshwater fishes.It is reported that the optimum development of W. attu is at a temperature range of 28.5 ∘ C−30 ∘ C [52,53].It is quite evident that the duration of larval development of fishes is longer in temperate waters [54,55].pH ranges between 7.9 and 8.2; however, the values of pH in the present study are in agreement with the earlier work [49].
Many other chemical parameters such as total hardness, alkalinity, nitrate, phosphate, sulphate, chloride, and magnesium in the culture tanks of Catla fry did not show wide variations.Total alkalinity was significantly greater where organic fertilization and feeds were applied to ponds [9].Alkalinity increases with organic fertilization because bacterially generated CO 2 from manure decomposition dissolves calcium and magnesium carbonate in pond water into calcium and magnesium bicarbonate.In Catla fry rearing tanks, calcium level ranged between 34 and 48 mg/L, which is in agreement with the previous results [9].Thus, successful hatchery production of fish larvae depends on many factors, the most important being the type of rearing system, physical and chemical parameters, and the type of diet used [9].However, the values of ammonia recorded in the present experiments showed low level when compared to previous study [49].Sugiyama and Kawai (1978) reported that higher concentration of dissolved oxygen decreases ammonia level through oxidation [56].Higher concentration of ammonia nitrogen is often noticed in fish culture ponds [57].Experiment of Pilar Olivar et al. (2000) on sea bass larval rearing illustrated that the survival and growth of reared larvae were a direct function of diet and that the type of rearing system did not adversely affect these parameters [54].Nevertheless, they point out that unionized ammonia and nitrate are the most dangerous metabolites for fry development and are very important in the first phases of ontogeny and hence should be maintained at a lower level.In the present study, the level of nitrite in the rearing system of Catla fry is lower when compared to the earlier results [49].Hence, the water quality should be maintained at optimum levels for the normal development of fish fry.

Conclusion
The results of feeding experiment of Catla fry suggest that Cyclopoid diet can be used as live feed for effective production of fry.The present study suggests that Cyclopoid and Cladoceran can be used as ideal live-feed and its use in the hatchery seed production will lead to sustainable as well as economically viable aquaculture activity.

Figure 1 :
Figure 1: Level of carbohydrate, protein, and lipid of Catla fry fed with different diets.

Table 1 :
Growth parameters of C. catla fry fed with different diets (mean ± SD).Note.* * and * denote significant level at 99% and 95% confident level, respectively.Different alphabet between types of feed denotes significant at 95% confidant level using Duncan Multiple Range Test (DMRT).
[44]e.* * and * denote significant level at 99% and 95% confident level, respectively.Different alphabet between types of feed denotes significant at 95% confidant level using Duncan Multiple Range Test (DMRT).growthrate) of the fry Catla in different feeding regimes.Body weight gain, survival, and SGR were calculated using the formula given by Aliyu-Paiko et al. (2010)[44]:

Table 1 .
The growth parameters pertaining to length and weight showed highest increase in Cyclopoid fed fry.The minimum increase was observed in Cladoceran fed fry.Moderate growth was observed in mixed diet.The length of Catla fry increased from 6.30 ± 0.10 mm to 26.03 ± 1.88 mm in Cyclopoid diet followed by mixed diet where the initial length was 6.10 ± 0.10 and final length was 25 ± 1.32 mm.In Cladoceran diet, Catla fry increased in length from 6.43 ± 0.12 to 22.11 ± 1.57 during the study period.The control diet fed Catla fry (Saunders' feed) showed increase in length from 6.17 ± 0.06 to 14.77 ± 1.63 mm.Similar trends were observed with respect to weight.The Cyclopoid diet fed Catla fry recorded the maximum weight gain of 50.3 mg followed by 38.66 mg in mixed diet, 32.87 mg in Cladoceran diet, and only 11.03 mg in the control diet (Table

Table 3 :
Level of dissolved oxygen (mg/L) in the rearing tanks of Catla fry (mean ± SD).Note.* * and * denote significant level at 99% and 95% confident level, respectively.Different alphabet between types of feed denotes significant at 5% level using Duncan Multiple Range Test (DMRT).

Table 4 :
Level of calcium (mg/L) in the rearing tanks of Catla fry (mean ± SD).
*Note.* * and * denote significant level at 99% and 95% confident level, respectively.Different alphabet between types of feed denotes significant at 5% level using Duncan Multiple Range Test (DMRT).

Table 5 :
Correlation coefficient between different water quality parameters in the Catla fry rearing tanks.* and * denote significant level at 99% and 95% confident level, respectively. *