Effect of polycultured fish on productivity of semi-intensive ponds

  El-GENDY,M.O

 Fish aquaculture; Sakha Aquaculture Research Unit, Central Lab. for Aquaculture Research, Abbassa, Agriculture Research Center, Egypt.

Abstract

                 This experiment was conducted at fish farm belonging to Governorate of Kafr El-Sheikh, ARE during the period from May to November 2009. The study aimed to investigate the effect of artificial feeding alone or combined with fertilization with different sources (organic duck manure or inorganic urea + super phosphate) on growth performance, feed efficiency, carcass traits, while body chemical composition and. In order to fulfill the objectives of the present study four treatment groups are allocated as follows: (T1): has served as control group and fed on 3% artificial diet. (T2): this group received artificial feed as in T1 plus duck manure at rate 5kg/feddan for 5 days weekly (T3): this group received artificial feed as in T1 plus duck manure as in T2 and inorganic fertilizers super phosphate 25kg and urea 20kg per feddan every 15 days (T4): this group received artificial feed plus the inorganic fertilizers as in T3.

           The artificial diet fed to the experimental groups contained 25% crude protein and was fed at a daily rate of 3% of the pond biomass and was fed 7 days weekly. The experimental period lasted 24 weeks after start. The experimental ponds (4200 m2) were stock with gray mullet, Liza ramada , Nile tilapia and common carp at rates of 8820, 1764, 12600 and 882, respectively.

            Results obtained are summarized in the following growth performance Averages of final weights, final length, weight gain(T1,T2,T3and T4 were 307.7,479.93,302.28 and424.49g respectively), length gain, specific growth rate and relative growth rate of T3(225.74,301.99,235.29 and313.52g respectively) and all of these parameters were significantly higher than those of other treatment groups. On the other hand, T3 showed the lowest (P<0.05) condition factor as compared to the other treatment groups.

NTRODUCTION

            In Egypt, few studies were carried out on the Egyptian fish farms and related activities. Imam and Hashem (1960) studies the spawning and development of Cyprinus carpio in Egyptian ponds. Shahen et al. (1960) investigated the carp culture in rice-fields. El-Zarka and Fahmy (1968) reported the effect of fertilization on Mugil cephalus in the Mex experimental fish farm. Bishai et al. (1972 & 1973) studied the biology, food and feeding habits and effect of supplementary food of the C. carpio in Serow fish Farm. The physico-chemical characteristices oif Manzalah fish were investigated by Seliem (1974). The food of C. carpio was reported by Bishai et al. (1973) under natural conditions at Serow fish farm and concluded that carp feeds mainly on food of animal origin. Rice-bran and cotton fedds mainly on food of animal origin. Rice-bran and cotton seeds cake are used as supplementary food for polyculture systems (El-Bolock and labib, 1966). El-Zarka and Fahmy (1968) studied the yield of Mugil cephalus in fertilized or manured ponds. They reported an increase in yields of about 36-77% in fertilized ponds compared to the control. The gut analysis of Mugil cephalus indicated that beside the inorganic particles found frequently in the alimentary canal there were diatoms, plant detritus, filamentous algae and small invertebrates (Ghazzawi, 1933 ; Bishara, 1967 and Hamza, 1974). The rearing of Mugil cephalus  and M. capito in Serow and manzalah fish fram was investigated by Essawy et al. (1974). Borhan (1978) studied fish culture in Abbasa ponds. Hussein (1984) investigated the biology of C. carpio, influence of age of the fish and environmental characters on each of the percentage of fertilizability and over wintering of carp fingerlings by using manure and inorganic fertilizers at Serow fish farm. At the same farm, Hussein (1995) studied the efefcts of organic, inorganic fertilizers and supplementary food for polyculture system.

2-MATERIALS AND METHODS

          The present study was conducted in the Fish Farm affiliated to Kafr El-Shiekh Governorate, Egypt, to evaluate the possibility of increasing fish production under semi-inetsive or polyculture system. The study extended from first May to 30th November, 2009.

2.1. Experimental ponds:

          The farm consists of several ponds, spawning concrete ponds, nursery pounds and rearing ponds.The experiment was performed in 4 nursery concrete ponds with bottom mud were 4200 m2 (40 x 105 m), the mean depth of all ponds was about 1.25 m.Each of these ponds has inlet and outlet water gates through which the water level is controlled.The feed water of the farm is mainly agricultural drainage water and comes from Elgarbia drain. The water system of the experimental ponds is maintained by gravity.There were four treatments each in a completely randomized design: T1 = feeding, T2 = feeding + manure,T3 = Feeding + manure + fertilizer (urea + super phosphate) and T4 = Feeding + fertilizer (urea + super phosphate).

2.2. Physico-chemical analysis of ponds waters:

          Monthly water samples were collected from each of the experimental ponds for measuring some physico-chemical parameters. The samples were collected from three fixed places at each ponds, then mixed together to form a composite sample. The samples were analyzed within few hours after collection. Some parameters such as temperature, pH and dissolved oxygen were measured in shadow. Five milliters of chloroform were added to each bottle sample as preservative.

          The water temperature was measured using mercury thermometer graduated from 0 to 100oC. Water temperature of the experimental ponds was measured by immersing the thermometer in pond water for 1 minute. Water temperature of different experimental ponds was recorded dialy at noon. Measuring was done at about 50 cm deep.The pH values were measured in situ using pH meter model 3050 Jenway electrochemical products, range from 0 to 14 in the sample afternoon daily.The dissolved oxygen was measured using dissolved oxygen meter model Jenway electrochemical products. The results were expressed in the sample as mg O2/L at early morning and afternoon dawn daily.

 2.3. Experimental fishes:

                    The experimental ponds were stocked with the different fish species, i.e. Oreochromis niloticus, Cyprinus carpio, Liza ramada and Mugil cephalus. O. niloticus fingerlings were stocked at an average initial total length of 5.73, 5.47, 5.47 and 5.06 cm and an average initial total weight of 4.33, 4.13, 3.93 and 4.00 g for the first (T1), second (T2), third (T3) and fourth treatment (T4), respectively. C. carpio fingerlings were collected from the same farm, were stocked with an average total length of 0.12, 0.10, 0.13 and 0.11 cm and an average total weight of 0.34, 0.31, 0.32 and 0.30 g for the T1, T2, T3 and T4, respectively. The average initial total length of M. cephalus fingerlings were 11.01, 10.73, 10.16 and 10.06 cm and an average initial total weight of 34.16, 31.54, 30.99 and 30.31 g for the T1, T2, T3 and T4, respectively. L. ramada fingerlings were stocked at an average total length of 4.65, 4.65, 4.34 and 4.33 cm and an average total weight of 8.85, 8.93, 7.80 and 7.92 g for the T1, T2, T3 and T4, respectively.

          Chemical analysis of experimental diet is presented in Table (1). Fishes were fed six days per week at a rate of 3% of the estimated fish-weight of feeding twice daily for all experimental period. Feed was applied throughout the experiment by broadcasting over pond water surface in the same place and fish were considered satiated when they did not show an interest on the feed.

Table (1) : Composition and proximate chemical analysis of the experimental diet.

* calculated by differences.

** Growth energy was calculated using values of 5.65, 4.1 and 9.45 kcal/g protein, carbohydrate and lipid, respectively. (Brett, 1973 and Jobling, 1983).

 2.4. Fertilizers applications:

          Mono super phosphate (15% P2O5) as a source of phosphorus and urea containing 46% nitrogen were added to the experimental ponds at half monthly rate of 25 kg/feddan, for mono super-phosphate, and 10 kg /feddan, for urea (Abo-Omer, 1998). At the beginning of the experimental period, the experimental ponds No. 3 and 4 were fertilized with pure duck manure (taken from Chinese duck houses at El-Khashaa Duck Farm), at a level of 4 kg/feddan/day, 5 days /week.

          At the beginning and end of the experiment, random samples of fish were taken and frozen for proximate analysis. Also, monthly random samples of at least 600, 42, 84 and 42 fish from O. niloticus, M. cephalus, L. ramada and C. carpio reared, respectively, were caught from each ponds by using fish wheels net. A triple been balance of capacity from 0.1 g to 1600 g was used for weighing the fish samples. Individual measurements of total length and weight of the fish samples were recorded to the nearest 0.1 mm and 0.1 g, respectively. Fish samples were taken in the morning.

3.5.Fish growth measurments:

 3.5.1.Total weight gain (TWG)      TWG (g/fish) = final /weight – initial weight

3.5.2.Condition factor (k):The condition factor (k) of a fish can be the mathemalical equation proposed by Fulton (1902) as follow:

                   W x 100

                K = ـــــــــــــــــــ

                        L3

Where:

K= condition factor, coefficient of condition or Ponderal index.

          W= total weight of fish in grams

          L= total length of fish in cm.

 3.5.3.Specific growth rate (SGR):

                        Ln W2 – Ln W1

              SGR = ـــــــــــــــــــــــــــــــــــــ  x 100

                              T

Where:

Ln = the natural log

W2 = final weight at certain period (g)

W1 = initial weight at same  period (g)

T = period of experimental (day)

3.5.4.Relative growth rate (RGR):

                   Total weight gain (g)

            RGR  = ــــــــــــــــــــــــــــــــــــــــ x 100

                          Initial weight  (g)

 3.5.5.Food conversion coefficient (FCR):

          The food conversion coefficient (ratio) is defined as the amount of dry food fed per unit live weight gain of fish.

                   Amount of feed given . g dry food

        FCR = ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ

                   live weight gain. g wet fish

2.6. Chemical analysis of feed and body composition:

          Proximate composition of dry matter crude protein, fat, ash and energy content were determined on the diet and fish. Fiber was determined on he diet. Dry matter was determined after the samples were dried to constant weight in an Oren at 105oC for diet and 70oC for fish. Crude proteins was analyzed using the Kjieldahl method, crude fat by ether extraction and fiber by drying and ashing after extraction with 0.5 mH2SO4 and 0.5 mNaOH. Ash content was determined after 12 h at 550oC in a muffle Furnace (A.O.A.C., 1990).

2.7. Statistical analysis:

          Statistical comparison between means was made by one way analysis of variance (ANOVA) (Snedector and Cochram, 1982 and SAS, 1993) and differences among means were tested by least significant differences (LSD). The significant level was P>0.05.

4. RESULTS AND DISCUSSION

4.1.chemical characteristics:

          Results of Table (2) shows the physico-chemical characteristics of experimental pond water during 7 successive months from May to November 2005 during this experiment. A large number of water quality parameters including water temperature, Do, pH, total alkalinity ammonia, nitrate, salinity and siccki were measured fortnightly throughout the experiment. Fertilization concomitantly affects wates quality with positive or negative consequences to fish survival and growth. Organic fertilizer acts an energy source for bacterial growth, but the aerobic decomposition of organic matter by bacteria is an important drain of oxygen supplies in ponds (Boyd, 1982).

               Each water quality parameters studies shows a different pattern of changes related to treatment (Table 2). Water temperature the trend of atmospheric temperature. Pond water temperature averaged 26.0oC in treatments T1, T2, T3 and T4 may be attribute to the increase in organic matter contents of these ponds.Table (2): Average physico-chemical characteristics of water ponds during five different treatments.

         Dissolved oxygen values varied from 8.5, 8.25, 8.15 and 8.20 mg/L for treatments T1, T2, T3 and T4. Dissolved oxygen (Do) concentrations in ponds are affected most by phytoplankton biomass, with greater production and consumption occurring at higher phytoplankton biomass (Boyd, 1990a). Diana et al. (1990 and 1991) reported that the oxygen differential (Do at top of water column minus Do at bottom) was significantly greater for inorganically fertilized ponds (7.6 mg/l) than for organically fertilized ponds (3.0 mg/l).pH remained fairly alkaline throughout the study period. Average pH ranged from 7.5, 7.5, 7.6 and 7.7 for treatments T1, T2, T3 and T4.

Boyd (1990) reported that application of ammonia and urea-based fertilizers can cause acidification of pond water because of nitrification, which produces two hydrogen ions from each ammonium ion. Salinity ppt and siccki disc reading (cm) was found to be 0.7, 0.68, 0.66 and 0.67 ppt for treatments T1, T2, T3 and T4 and siccki disc reading was found to be 32, 30, 32 and 30 cm for treatments T1, T2, T3 and T4 (Hussein and Abdel-Hakim, 2003).

4.2. Growth performance parameters:

4.2.1.Nile tilapia(o.niloticus)

               Results in Table (3) are in agreement with the finding of Hussin (1995) who reported that the growth in length values of O. niloticus   varied from a maximum of 20.57 cm, in polyculture ponds treated with inorganic fertilizers + 20% artificial feed to a maximum of 12.52 cm in monoculture ponds treated with inorganic fertilizers in the second season, the average growth in length value of this species reached to 16.1 cm this heads to the conclusion that the growth in length of O. niloticus  in polyculture systems in much higher than the monoculture. Also, the application of inorganic fertilizers increased the growth rate of this species. Therefore, the present growth in length values of O. niloticus  was higher that recorded by Badawy (1993). He reported that the average growth in length values of male and female O. niloticus  in polyculture system in seroq fish farm were 14.1 and 13.9, respectively. Also, the result of Table (4) are in accordance with that of Hussein (1995) who indicated that the daily growth rate of O. niloticus  in polyculture treated with inorganic fertilizers + 2% artificial feed was much higher than in other treated ponds.

Table ( 3): Effect of source of fertilization or artificial feeding on body weigh gain, specific growth rate, condition factor and relative growth rate of Oreochromis Niloticus reared in poly culture system (mean±SE).

a,b,c… within each raw bearing the same letters do not differ significantly P<0.05 other wise the do

T1 = Feeding ; T2 = Feeding + manure ; T3 = Feeding + manure + fertilizer (U+SP) ; T4 = Feeding + fertilizer (U+SP)

4.2.2. Common carp (Cyprinus carpio ) :

               Results of growth performance of common carp as affected by the applied treatments are presented in Table (4). Averages of initial weight and lengths had ranged between 0.53 and 0.55 g and 0.16 to 0.17 cm, respectively   with   insignificant   differences   among   the experimental groups at the start. Final body weights of common carp at termination of the experiment was the highest P<0.05 (480.48 g) for T3 group followed in a significant (P<0.05) order by T4, T2 and T1, respectively.

              As presented in Table (4) T3 recorded the highest SGR value (3.15%)   which   differed  significantly  (P<0.05) from the value of T1 (2.94%), however differences in this trait among T3, T2 and T4 were insignificant also differences in SGR among T1, T2 and T4 were insignificant.

Table (4): Influences of sources of fertilizers and artificial feeding on body weight gain, specific growth rate, condition factor and relative growth rate of Mugil cephalus reared in poly culture system (mean±SE).

a,b,c… within each raw bearing the same letters do not differ significantly P<0.05 other wise the do

               Concerning RGR, averages were found to be 55954.07, 65964.14, 87260.00 and 75483.01 percent for T1, T2, T3 and T4, respectively. Analysis of variance of results revealed that T3 had significantly (P<0.05) higher RGR followed by the other treatment groups (Table 4). In general results presented in Table (5) revealed that common carp reared together with mullet species and tilapia in earthen ponds performed in their growth parameters when ponds received artificial diet + duck manure and inorganic fertilizers followed by the other treatment groups. In this connection researchers have shown that common carp production in fertilized ponds in temperate regions was 2 to 20 times higher than that in unfertilized ponds (Mortimer and Hickling 1954).          

4.2.3. Liza ramada  :

     Growth performance parameters of mullet species (Liza ramada ) are presented in Table (5). As presented in this Table average initial weight had ranged between 7.8 and 7.9 g with insignificant differences among the treatment groups at the experimental start indicating that the distribution of the fish at the start was