Effect of mixed feeding statageis on growth performances of striped cat fish (Pangasianodon hypothalamus) and catla (Catla catla) under polyculture

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1 AJASTHE ASIAN JOURNAL OF ANIMAL SCIENCE The Volume 9 Issue 1 June, e ISSN Open Access RESEARCH ARTICLE Effect of mixed feeding statageis on growth performances of striped cat fish (Pangasianodon hypothalamus) and catla (Catla catla) under polyculture SWETA PRADHAN, S. NANDA, TULSANKAR SMITA SADANAND, G.C. KUND, D. CHOUDHURY AND R.K. RATH Author for Correspondence - S. NANDA P.G. Department of Aquaculture, College of Fisheries (O.U.A.T.), Rangailunda, BERHAMPUR (ORISSA) INDIA saumyendra.nanda@rediffmail.com See end of the article for Coopted authors ABSTRACT... A 120 days feeding trial was conducted in triplicate in the cement cistern to investigate the effect of mixed feeding statagies on growth performances of striped cat fish ( Pangasianodon hypothalamus) and catla (Catla catla) under polyculture system. Both the species of uniform size and initial weight were stocked at a ratio of 60:40 (striped cat fish 60% and catla 40%) by adopting a total stocking density of 30,000 numbers of fingerlings per ha. Experimental diets were prepared containing varying levels of proteins from the plant source like soybean, sesame oil cake, mustard oil cake following the standard procedures for formulation of pelleted feed. The feed ingredients like mustard oil cake, sesame oil cake. soybean, de-oiled rice bran, corn flour, vegetable oil, vitamin and mineral premix were procured and utilized for the purpose. Five experimental diet were prepared as T 0 : Control diet with the mixture of mustard oilcake and de-oiled rice bran, Low protein diet (T 1 ) with 15 per cent crude protein, High protein diet (T 2 ) with 30 per cent crude protein,t 3 One day low protein and one day high protein on alternate day and (T 4 ) Two days low protein and two days high protein on consecutive manner. The feed was provided to the experimental animals at a rate of 4 per cent of their body weight daily. Among all the different treatments, striped cat fish and catla attended maximum average weight gain under the influence of one day low protein and one day high protein diet in alternate manner (T 3 ) followed by T 2 (with high protein diet) and T 1 (with low protein diet).the growth performances under the treatment (T 4 ) was considered to be least. The analysis of variance revealed a significant difference ( =0.05) between the treatments and a highly significant difference was reported between the days of culture irrespective of fish species. The treatment (T 3 ) was considered to be the best out of all other treatments in term of average weight gain (g), increment in length, minimum FCR and PER with higher specific growth rate. KEY WORDS... Striped cat fish, Catla, Growth performance, Polyculture HOW TO CITE THIS ARTICLE - Pradhan, Sweta, Nanda, S., Sadanand, Tulsankar Smita, Kund, G.C., Choudhury, D. and Rath, R.K. (2014). Effect of mixed feeding statageis on growth performances of striped cat fish (Pangasianodon hypothalamus) and catla (Catla catla) under polyculture. Asian J. Animal Sci., 9(1) : ARTICLE CHRONICLE - Received : ; Revised : ; Accepted : INTRODUCTION... Pangasianodon hypopthalmus formerly known as Pangasius sutchi is popularly known as striped cat fish or Pangas or Thai-Pangas in some part of the Asian countries. The exotic species gained much popularity in Bangladesh because of its rapid growth, easy culture system, high disease resistance and tolerance to a wide fluctuation of environmental changes. P. hypopthalmus is omnivorous in nature, feeding on algae, higher plants, zooplankton and insects. Some of the larger specimens also take fruit, crustaceans, and fishes too. HIND INSTITUTE OF SCIENCE AND TECHNOLOGY

2 SWETA PRADHAN, S. NANDA, TULSANKAR SMITA SADANAND, G.C. KUND, D. CHOUDHURY AND R.K. RATH Thai-Pangas has emerged as a commercially significant candidate fish species in freshwater fish farming in Andhra Pradesh, the premier fish producing state in India. P. hypopthalmus is currently cultured in the state under mono as well as poly farming systems. Two types of culture systems have been practiced in Bangladesh for P. hypophthalmus farming: viz., like monoculture (following intensive culture strategy) and polyculture (following semi-intensive culture strategy). In the polyculture systems, the production of P. hypophthalmus is about tons/ha. In the case of the intensive commercial culture, production is about tons/ ha with animal protein rich diets and water exchange (BFRI, 1998). The semi intensive farming of P. hypothalamus with other species of carps stocked at a ratio 84.3:14.54:1.16 for Thai-pangas, rohu and catla, respectively suggests that the Thai-pangas can be stocked a rate of 5 10 no/m 2 in still water earthen ponds having > 2 m water depth by adopting the latest management methods of feeding fishes with nutritionally balanced soy meal- based extruded floating feeds, and with or without aeration. In the farmers ponds fishes re-fed with traditional de-oiled rice bran based feeds in different combinations either as mash or farm cooked feed with crude protein level varying from 12 to 22 per cent yields good growth. The freshwater catfish requires relatively high protein level (>40%) in its diet for optimal growth, but the major problem associated with culturing of catfish is high operating cost which accounts more than 50 per cent of the total cost of production. The only possible way to reduce the feed cost is to develop appropriate feeding management strategies (De Silva, 1985). De Silva (1985) opined that adoption of mixed feeding schedules where a high protein is alternated with a low protein diet is cost effective in semi-intensive system of culture. The study on the similar lines has been conducted in the past for murrels, rohu, Indian major carps, common carps and tilapia (Haashim, 1994; Nandeeshaet al., 1994, 1995; Patel and Yakupitiyage, 2003). Fishes fed with alternatively of high protein and low protein indicated on one day alternative and two day alternative as in case of rohu (Labeo rohita) and catla (Catla catla) by Nandeesha et al. (1993) with common carp. Alternate feeding schedule also helps to reduce the nitrogen input substantially compared to continuous feeding of high protein diet (Nandeesha et al., 2002). Polyculture is undertaken with Indian major carps. One of the important facts is that the fish can be easily acclimatized with artificial feed under controlled conditions. It can be cultured in cage and pen culture. Pangasid catfish is cultivated both under monoculture as well as polyculture with Indian major carps and Chinese carps. Poly farming is undertaken with Indian major carps due to its excellent growth rate; feed conversion efficiency, multiple harvests, yielding quick economic returns, unique texture with export potentiality and with possibility of farming even in small ponds. It is expected that polyculture may produce a better result if the fishes with different feeding habits are stocked in proper ratios and combinations. The productivity of the aquatic system is thus increased more efficiently due to utilization of available ecological niches within the environment. Adoption of mixed feeding schedules where a high protein diet alternated with low protein diet is cost effective in semi-intensive culture. Mixed feeding schedule is based on the concept that digestibility of feed varies from day to day, following an appropriate cyclic pattern. The usefulness of mixed feeding schedules for reducing feed cost has been pointed out for the species, Pangasianodon hypophthalmus and Catla catla, under poly culture system. Hence, in the present investigation an attempt has been made to study the growth performance of Thai-pangas and catla under polyculture system in cement cisterns with a stocking density of 30,000 fingerlings/ha with provision of formulated feed under different treatments following the mixed feeding strategies. RESEARCH METHODS... Considering the importance and growth performances of Pangasianodon hypophthalmus, an attempt has been made in the present investigation to study the growth performance of the fingerlings of P.hypopthalmus and Catla catla under polyculture system with a stocking density of 30,000 fingerlings / ha with provision of supplementary feeding. Experimental diets were prepared containing varying levels of proteins from the plant source like soybean, sesame oil cake, mustard oil cake following the standard procedures for formulation of pelleted feed. The feed ingredients like mustard oil cake, sesame oil cake. soybean, de-oiled rice bran, corn flour, vegetable oil, vitamin and mineral premix were procured and utilized for the purpose. Five experimental diet were prepared as T 0 : Control diet with the mixture of mustard oil cake and de-oiled rice bran, Low protein diet (T 1 ) with 15 per cent crude protein, high protein diet (T 2 ) with 30 per cent crude protein, T 3 One day low protein and one day high protein on alternate day and (T 4 ) two days low protein and two days high protein on consecutive manner. Each experimental tank of 21 m³ was stocked with 60 numbers of 30 days old fingerlings comprising of 60 per cent striped cat fish and 40 per cent catla with more or less similar body weight and length. The experiment was conducted for a period of 120 days with periodical replenishment of water at every fortnight intervals. The fishes were fed at a rate of 4 per cent of their body weight per day in two equal installments. The water quality parameters like ph, temperature, dissolved oxygen; alkalinity was measured from each of the experimental containers at fortnightly intervals by following the standard procedures (APHA, 1985). During monthly interval, minimum 50 per cent of the cultured fishes were sampled species wise. 8

3 EFFECT OF MIXED FEEDING STATAGEIS ON GROWTH PERFORMANCES OF STRIPED CAT FISH & CATLA UNDER POLYCULTURE The growth parameters in term of increment in length (cm), increment in weight (g), specific growth rate (%), percentage weight gain, daily weight gain (g), percentage specific growth rate, food conversion ratio (FCR), and protein efficiency ratio were calculated by following the standard procedures which are as follows : Percentage weight gain = Daily weight gain (g) = (loge SGR = Final weight of fish Initial weight of fish Final body weight Total no. of Total dry food intake(g) FCR = Total live weight gain(g) Total weight gain (g) PER = Total protein intake (g) Initial weight of fish Total no. of experimental days 100 Final weight of fish Initialweight of fish loge experimental days Initial body weight 100 Statistical analysis : The data gathered during the process of present investigation were subjected to statistical analysis like analysis of variance by following the standard method to find out difference of mean to know the significant differences between the treatments to arrive at a conclusion with respect to efficacy of the feed. RESEARCH FINDINGS AND ANALYSIS... The proximate composition of the control and experimental diets were analyzed and are presented (Table 1 and 2). The experimental diet under the treatment (T 0, T 1, T 2,) had an average crude protein percentage of 18.52; and 28.49, respectively. The fat percentage varied with slight variation ranging from as minimum to a maximum of The crude fibre content of the experimental diets was estimated to be 7.67, 5.91 and 6.12 per cent for the diets under treatment T 0,T 1 and T 2, respectively (Table 2). Growth performances of striped catfish : Under the treatment T 0 (control diet) the striped cat fish attained 28.63±0.66 g from the initial average weight 6.51± 0.28 g within a culture period of 120 days with corresponding increment in total length. Fishes fed with low protein diet (T 1 ) had a final average weight of 29.93±0.41g from an initial weight Table 1 : Proximate composition of different feed ingredients used for preparation of experimental diets Ingredients Proximate composition Moisture Crude protein Crude fat Total ash Crude fibre Deoiled rice bran Mustard oil cake Soybean meal Sesame oil cake Corn flour Table 2 : Ingredient proportion and proximate composition of experimental diets used in the study (% on dry matter basis) Diets T 0 (control) T 1 (15%) T 2 (30%) Ingredients Sesame oil cake Soybean meal Corn flour Deoiled rice bran Mustard oil cake Oil Vitamin/mineral premix Proximate analysis Moisture Crude protein Crude fat Ash Crude fibre NFE GE(Kcal/100g)

4 SWETA PRADHAN, S. NANDA, TULSANKAR SMITA SADANAND, G.C. KUND, D. CHOUDHURY AND R.K. RATH of 8.40± g during the experimental period. The striped cat fishes under the treatment T 2 fed with high protein diet performed slightly better than the previous treatment. At the end of 120 days of experimentation period, the striped cat fish attained an average weight of ±0.66 g from an initial average weight of 8.78±0.25 g with a significant increment in weight between 60 to 90days and 90 to 120 days of culture period (Table 3). Under the treatment (T 3 ) striped cat fishes fed with one day low protein and one day high protein diet alternatively showed a significant difference from that of the other treatments. The species attained an average weight of ±0.64 g at the end of 120 days of experimentation period from an initial average weight of 10.70± g. In the treatment (T 4 ), the striped cat fish fed with two days low protein diet and two days high protein diet consecutively exhibited poor growth. At the end of 120 days of experimentation period, the species had attained a maximum of 39.80±0.52 g with corresponding increment in average length. The two way classification of analysis of variance without replication indicated a significant difference between treatment and experimental days ( =0.05). A highly significant difference was noticed between experimental days and between treatments the difference was calculated to be significant. Growth performance of catla : It is evident from Table 4 that under the treatment T 0 (control diet) the catla had attained ±1.13 g from the initial average weight 10.73± 0.11 g within a culture period of 120 days with increase in average length from 5.40± cm to 22.40±0.75 cm during the experimental period. But under the treatment T 1 (low protein diet) catla attained ±1.04 g from the initial average weight 10.66±0.61 g within a culture period of 120 days. The treatment growth performances of catla fed with high protein diet (T 2 ) performed slightly better than the previous treatment with a gradual increase in average weight. At the end of 120 days of experimentation period, catla had attained an average weight of ±1.83 g from an initial average weight of 10.46±0.41 g. Catla fed with one day low protein and one day high protein diet alternatively under the treatment T 3 attained an average weight gain ±1.66 g at the end of 120 days of experimentation from an initial average weight of 10.26±0.25 g. Between 30 to 60 days of culture period, the average increment in weight was very fast and it was reported to be ±0.75 g. On an average, the best growth performance in terms of increment in average weight was recorded under the treatment T 3. The corresponding increment in average length between 60 to 90 days and 90 to 120 days of culture period was reported to be 16.70±0.96 cm to 19.83±0.92 cm and from 19.83±0.92 cm to 23.43±1.00 cm, respectively. In the treatment T 4, catla fed with two days low protein diet and two days high protein diet consecutively exhibited poor growth performances in comparison to the other treatments. Between 90 to 120 days of culture period, the average the weight of catla was reported to increase from 81.76±0.88 g to ±0.66 g (Table 4). The two way classification of analysis of variance without replication indicated a significant difference between treatment and experimental days ( =0.05). A highly significant difference was noticed between experimental days and between treatments and the difference was calculated to be significant. Table 3 : Average increment of length and weight of striped cat fish under different treatments in poly culture systems T 0 T 1 T 2 T 3 T 4 Days Length (cm) Weight (g) Length (cm) Weight (g) Length (cm) Weight (g) Length (cm) Weight (g) Length (cm) Weight (g) ± ± ± 8.40± 6.63± ± ± ± 6.50± 9.42± ± ± ± ± ± 19.0± ± ± ± 15.90± ± ± ± ± ± ± ± ± ± ± ± ± ± 29.93± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±0.52 ± indicates standard deviation Table 4 : Average increment of length and weight of catla under different treatments in poly culture systems T 0 T 1 T 2 T 3 T 4 Days Length (cm) Weight (g) Length (cm) Weight (g) Length (cm) Weight (g) Length (cm) Weight (g) Length (cm) Weight (g) ± 10.73± ± 10.66± ± ± ± 10.26± ± 10.50± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± 75.50± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±0.66 ± indicates standard deviation 10

5 EFFECT OF MIXED FEEDING STATAGEIS ON GROWTH PERFORMANCES OF STRIPED CAT FISH & CATLA UNDER POLYCULTURE Growth parameters of fish species under treatment : The increment in total length from the day of initiation of the experiment to the day of termination of the experiment was calculated to be 10.07±0.48 cm and 16.63±0.50 cm for striped cat fish and catla, respectively under the influence of one day low and one day high protein diet. The final weight gains for the species under polyculture were also reported to be 73.36±0.37 g and ±0.95 g with daily weight gain (g) values of 0.61and 1.28 for striped cat fish and catla, respectively. The specific growth rate (%) for striped cat fish and catla under the treatment (T 3 ) fed with the experimental diet was calculated to be 1.87 and 2.30, respectively. The food conversion ratio of 1.07 and protein efficiency ratio of 0.96 were also obtained for the species fed with diet (T 3 ). In contrast, the specific growth rate (%) for striped cat fish and catla, under the treatment (T 2 ) fed with high protein diet were calculated to be 1.44 and 1.89; respectively. The food conversion ratio of 1.37 and protein efficiency ratio of 1.29 were also obtained for the species fed with high protein diet (Table 5). Out of all the treatments, the fishes under polyculture system fed with low and high protein diet (T 3 ) on one day alternate was significantly different from other treatments in terms of average weight gain, higher growth rate, feed utilization, better feed conversion ratio, protein efficiency ratio etc. The best growth performances of the fishes was observed in the treatment (T 3 ) followed by the treatment (T 2 ). The highest average weight gain was reported for striped cat fish (82.06±0.64 g) than catla (164.03±1.66 g). In the present investigation, the water quality parameters from the experimental units like temperature, dissolved oxygen, ph, total alkalinity were reported to vary from 28.5± C to ± C; 5.20 ± 0.46 to 7.80 ± 0.40 mg/l; 8.10 ± to 8.60±0.48 and ± to ± 2.25 mg/l of calcium carbonate, respectively. The fluctuation in the above water quality parameter in the present investigation was mainly attributed due to the increased rate of photosynthesis, over population of phytoplankton, consumption of oxygen through respiration by the cultured fish species, nature of bottom deposits and accumulation of residual content of the feed. Earlier work also reveals that, the ideal temperature, transparency, dissolved oxygen content and ph value ranging from 20 to 35 0 C, 25 to 35 cm, 5.0 to 8.0 mg/l and 6.7 to 8.6, respectively are considered to be ideal for culture of Thaipangas (Islam, 2008; Zannatul and Farhana, 2006; Sayeed, 2008). The values of water temperature, transparency, dissolved oxygen content, ph and total alkalinity as discussed earlier suggest that the environmental conditions maintained are well within the ideal range to boost the production of striped cat fish and carps from the culture systems. The finding of the present investigation is in agreement with the earlier results. Mixed feeding schedules with varying dietary protein levels on the growth of sutchi cat fish and silver carp indicated a better growth performance of the species fed with low protein diet alternate with high protein diet on alternate days resulting with best growth, feed utilization and production (Ali et al., Table 5 : Growth parameters of striped catfish and catla under polyculture fed with different diets T 0 T 1 T 2 T 3 T 4 Parameters Pangas Catla Pangas Catla Pangas Catla Pangas Catla Pangas Catla Initial length (cm) 6.36 ± 0.15 Final length (cm) ± 0.90 Initial weight (g) 8.51 ± 0.28 Final weight (g) ± 0.66 Increment in length (cm) 9.84 ± 0.50 Weight gain (g) ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± Percentage weight gain Food conversion ratio Daily weight gain (g) Specific growth rate (%) Protein efficiency ratio Overall survival (%) ± indicates standard deviation

6 SWETA PRADHAN, S. NANDA, TULSANKAR SMITA SADANAND, G.C. KUND, D. CHOUDHURY AND R.K. RATH 2005). Polyculture of Thai pangas with carps and prawn using low cost formulated feed under different combinations of stocking density indicated that, the polyculture of pangas was more profitable than its monoculture (Islam et al., 2008). The study also revealed that, when pangas, catla, rohu and prawns are stocked at a rate of 10,000: 2,500: 5,000 and 3,750 numbers per ha gave best result in terms of net weight gain, survival (%), FCR, PER, MDW gain, total production when compared to other treatments. Sayeed et al. (2004) opined that, significantly higher growth rate of Thai Pangas with the highest SGR (1.60% per day) was achieved along with a FCR value of 1.96 while fed with diet containing 32 per cent protein. Ali et al. (2005) conducted a field trial to investigate the effect of alternate feeding schedules on the growth and production of Thai pangas. The study revealed that, feed conversion ratio and protein efficiency ratio were lower in regular feeding with high protein diet (H) and other mixed feeding schedules compared to continuous feeding with a low protein diet (L) and further strengthened the fact that, the protein efficiency ratio did not reflect the growth trend, instead it varied inversely with the amount of crude protein in the diet. The higher protein efficiency ratio recorded in the low protein diet suggests the efficient utilization of the small quantity of protein provided for growth. Effect of mixed feeding schedules with varying dietary protein levels on the growth of sutchi cat fish and catla in ponds clearly reveals that, mixed feeding schedule of a low protein diet alternate with a high protein diet resulted with best growth, feed utilization and production compared to feeding striped cat fish and catla with a high protein diet continuously. Acknowledgement : Authors are thankful to the Director, College of Fisheries, Rangeilunda, Berhampur for providing all the facilities for the present investigation. COOPTED AUTHORS SWETA PRADHAN, TULSANKAR SMITA SADANAND AND R.K. RATH, P.G. Department of Aquaculture, College of Fisheries, Orissa University of Agriculture and Technology, Rangailunda, BERHAMPUR (ORISSA) INDIA D. CHOUDHURY AND G.C. KUND, College of Fisheries, Orissa University of Agriculture and Technology, Rangailunda, BERHAMPUR (ORISSA) INDIA LITERATURE CITED... Ali, M.Z., Haque., M.K.I., Parveen, R., Hussain, M.G. and Mazid, M.A. (2005). Growth and reduction of cost production of Pongasianodon. hypopthalmus. (Sauvage, 1878) with alternate feeding schedules. Indian J. Fisher, 52(4) : Ali, M.Z., Hossain, M.A. and Mazid, M.A. (2005). Effect of mixed feeding schedule with varying dietary protein levels on the growth of sutchi catfish, Pangasius hypophthalmus (Sauvage) with silvercarp, Hypopthalmichthys molitrix (Valenciennes) in ponds. Aquaculture Res., 36(7) : AOAC (1975). Methods of analysis. Association of Official Analytical Chemists, (12 th Edn.). Washington, DC pp. APHA (1985). Standard methods for the examination of water and waste water, (16 th Edn.) American Public Health Association, Washington, DC, 1266 pp. BFRI (Bangladesh Fisheries Research Institute) (1998). Studies on the stress factor in relation to the disease of freshwater fishes. Research progress report. Bangladesh Fisheries Research Institute. Freshwater Station, Mymensingh, Bangladesh. Bhanu, Ch. Prakash, Reddy, D. Ravindra Ku., Reddy, G. Vidya Sagar and Hari Babu, P. (2011). Farming ofpangasius hypopthalmus in ponds. Aqua. Int., 18(11) : De Silva, S.S. (1985). Performance of Oreochromis niloticus (L.) fry maintained on mixed feeding schedules of differing protein content. Aquaculture & Fisheries Mgmt., 16 (4) : Haashim, R. (1994). The effect of mixed feeding schedules of varying dietary protein content on the growth performance of Channa striata fry. Asian. Fisher. Sci., 7 (2&3) : Islam, Md. S., Haq, K.A. and Rahman, Md, A. (2008). Polyculture of Thai-Pangas (Pangasius hypophthalmus) Sauvage 1878 with carps and prawn : a new approach in polyculture technology regarding growth performance and economic returns. Aquacul. Res., 39 (15) : Khan, S., Hossain, M.S. and Haque, M.M. (2009). Effect of feeding schedule on growth, production and economics of pangasid cat fish (Pangasius hypopthalamus) and silver carp (Hypopthalmichthys molitrix) poly culture. J. Bangladesh Agril. Univ., 7(1) : Nandeesha, M.C., De Silva, S.S. and Krishna, M.D. (1993). Evaluation of mixed feeding schedules in two Indian major carps, catla (Catla catla) and Rohu (Labeo rohita), pp In: Kaushik, S.J. and Luquet, P. (eds.) Fish nutrition in practice. INRA Editions, Paris, France. Nandeesha, M.C., De Silva, S.S., Krishna, M.D. and Dathari, K. (1994). Use of mixed feeding schedules in fish culture. I. Field Trials on catla Hamilton Buchanan) Rohu, Labeo rohita (Hamilton) and common carp, Cyprinus carpio L. Aquaculture & Fisheries Mgmt., 25 (6) :

7 EFFECT OF MIXED FEEDING STATAGEIS ON GROWTH PERFORMANCES OF STRIPED CAT FISH & CATLA UNDER POLYCULTURE Nandeesha, M.C., De Silva, S.S. and Krishna, M.D. (1995). Use of mixed feeding schedules in fish culture in fish culture: performance of common carp, Cyprinus carpio L., on plant and animal based diets. Aquaculture Res., 26 (3) : Nandeesha, M.C., Gangadhara, B. and Manissery, J.K. (2002). Further studies on the use of mixed feeding schedules with plant-and animalbased diets for common carp, Cyprinus carpio (Linnaeus). Aquaculture Res., 33 (14) : NRC (National Research Council), (1993). Nutrient requirements of warm water fishes and shellfishes. National Accademy of Sciences, Washington, DC, USA. Patel, A.B. and Yakupitiyage, A. (2003). Mixed feeding schedules in semi-intensive pond culture in Nile tilapia, Oreochromis niloticus L. is it necessary to have two diets of different protein content. Aquacult. Res., 34 (14) : Saroha, P.R. and Garg, S.K. (2007). Growth performance ofcirrhinus mrigala (Ham.) Fingerlings maintained on mixed feeding schedule of diet having different protein content. Indian J. Fish., 54(4) : Sayeed, M.A.B., Hossain, G.S., Mistry, S.K. and Haq, K.A. (2008). Growth performance of thai pangus ( Pangasius hypopthalmus) in polyculture system using different supplementary feeds. Univ. J. Zool. Rajshahi Univ., 27: Sehagal, H.S. and Toor, H.S. (1991). Comparison of feeding strategies based on biomass and biomass-pond interactions. In: Fish Nutri. Res. in Asia, P , S.S. De Silva (Ed.) Asian Fisheries Society, Manilla, Phillipines. Ferdoushi, Zannatul and Haque, Farhana (2006). Effect of different stocking ratio of Pangasid Catfish (Pangasius hypopthalmus) and Silver carp (Hypophthalmicthys molitrix) on better water quality maintenance in cat fish farming. Pakistan J. Biol. Sci., 9(9): t h Year of Excellence 13