Enhancing Growth of Common Carp, Rohu and Mozambique Tilapia through Plant Substrate: The Role of Bacterial Biofilm

Experiments were conducted to enhance the growth of common carp (Cyprinus carpio), rohu (Labeo rohita) and Mozambique tilapia (Oreochromis mossambicus) through use of sugarcane bagasse as substrate. Bagasse was suspended in water with or without supplementation with fertilizers. Bagasse supplemented with cattle dung and urea favoured higher zooplankton production and significantly (p < 0.05) increased fish growth by over 50% compared to bagasse or fertilizers on their own. This higher production of fish is attributed to bacterial biofilm promoted on the substrate which, apart from forming food for zooplankton and fish, contributed to improved water quality by lowering ammonia.     

Comparison of Tilapia Monoculture and Carp Polyculture in Fertilized Earthen Ponds

A comparison of a monoculture of Nile tilapia Oreochromis niloticus and a polyculture of carps (silver carp Hypophthalmichthys molitrix; rohu Labeo rohita; and mrigal Cirrhinus mriga la; ratio 4:3:3) was carried out in 200-m² earthen ponds fertilized with cattle manure and supplemented with inorganic fertilizer at 3-kg nitrogen and 1.5-kg phosphorus/ha per day. A control treatment of a tilapia monoculture without fertilizer inputs was included to assess the effect of pond basal fertility. Net yields of 23.5 kg/pond per 112 d (3.8 t/ha per 1 yr) in the tilapia monoculture and 19.2 kg/pond per 112 d (3.1 t/ha per yr) in the carp polyculture were not significantly different; net yields from unfertilized tilapia monoculture ponds were negative. In the carp polyculture, silver carp was the dominant species at harvest contributing 73% of the total net fish production compared to 9% and 19% by rohu and mrigal, respectively. Water quality data suggested that tilapia yields could have been further improved by increasing fertilization rate but that critical dissolved oxygen concentration constrained this option for carp polyculture.     

Water Quality and Growth of Rohu,Labeo rohita,in a Biofloc System

We evaluated the technical feasibility of reducing water dependency of rohu, Labeo rohita, culture with biofloc under light-limited indoor culture. Biofloc and control treatments were conducted in 700-L indoor tanks at three different stocking densities (STD): 1.3, 2.6, and 3.9 Nos. fish m^?2 of surface area of tank for a period of 90 days. In biofloc treatment, fish were fed 20% crude protein feed and extra organic carbon in the form of wheat flour, whereas in case of control treatment they were fed 30% crude protein feed only. Fish survival was 100% in both the treatments. Lower stocking density produced larger fish, but growth was similar within stocking densities among control and biofloc treatments. The nutritional quality of biofloc was found to be quite suitable for rohu. Frequency of water exchange was significantly less in biofloc treatments as compared to the control ones.     

Immune response, growth and survival of Labeo rohita fingerlings fed with levamisole supplemented diets for longer duration

The study was to determine the effect of long-term administration of different dosages of levamisole on growth, immune response and disease resistance against Aeromonas hydrophila & Edwardsiella tarda in Labeo rohita fingerlings. Fish were fed with four different dosages of levamisole (0, 125, 250 and 500 mg kg⁻¹ diet) for 56 days. Different serum biochemical and haematological parameters such as serum total protein content, albumin content, globulin content, albumin/globulin ratio, glucose content, leucocytes count; cellular immune parameters including superoxide anion production, phagocytic activities, lymphokine production index; humoural immune parameters including lysozyme, complement and serum bactericidal activities were evaluated after 14 days interval. After 56 days, fish were divided into two subgroups under each treatment group for challenge with pathogens A. hydrophila and E. tarda . The cumulative mortality (%) and agglutinating antibody titre was recorded on 28th day postchallenge. WBC count, phagocytic ratio, lymphokine production index, lysozyme activity and serum bactericidal activity were increased upon administration of levamisole dosages for long term. However, the growth performance and survival against pathogens was not significantly changed over 56 days administration of levamisole. But incorporation of moderate dosage of levamisole for 42 days results better immune response without effect on growth and survival of L. rohita fingerlings.     

Integrated Duck-cum-Fish Farming in Bangladesh

An experiment on integrated duck-cum-fish farming was conducted in 11 ponds of 0.1 ha each at the Fisheries Research Institute, Mymensingh, Bangladesh. Khaki Campbell layer ducks Anas platyrhychos were housed directly over the pond water surface at 200, 400 and 500 dncks/ha. Each density had three replicate ponds and two ponds had no ducks. Fish fingerlings were stocked at a total density of 8,850/ha. The species composition was silver carp Hypophthalmicthys molitrix 33.9%; catla Catla catla 12.4%; rohu Labeo rohita 18.1%; mrigal Cirrhina mrigala 28.8%. grass carp Ctenopharyngodon idella 1.4% and sor puti Puntius gonlonotus 5.4%. The fish were not given any supplemental feed, and the ponds were not fertilized except for the split duck feed and duck manure falling directly into the ponds. Ducks were fed with a feed formulated from locally available ingredients.
After one year the fish were harvested. The yield of fish increased with an increase in duck density. Highest net fish production of 4,250 kg/ha/yr was obtained from ponds with 500 ducks/ ha, compared to 490 kg/ha/yr from the control ponds. Manure of each duck contributed a net fish yield of 6.9–7.5/yr. Average egg production was 237 eggs per female duck per year. Economic analysis of the technology showed a net profit of about 100% of the total costs, indicating the economic viability of the technology.     

Larval fish movement in the River Lohajang,Tangail, Bangladesh

Larval fish drift and distribution patterns were studied in the River Lohajang, a tributary of the River Jamuna, Bangladesh, during the monsoon seasons (June - October) of 1992, 1993 and 1994. Larval fish drift peaks with the water levels of the River Jamuna. In all three years, the Indian carp, Catla catla, Labeo rohita L. and Cirrhinus mrigala, were associated with the first pulses, but were absent from drift samples after September. Hilsa species and other non-identified fish species were found throughout the monsoon season. The highest larval fish densities were found in the upper strata of the river, near the shore. The drift densities of these fish became evenly distributed through time. Water turbidity probably influenced the vertical and horizontal distribution, and the absence of diel patterns. The most important species in the larval drift were Hilsa spp., followed by Labeo rohita L., Glossogobius giuris L. and Rasbora daniconius. Among the major carp, Labeo rohita was the dominant species, contributing 80-90%. The impact of flood control programmes on the reproduction of riverine and larval fish drift is discussed.     

Effect of understocking density of channel catfish fingerlings in intensively aerated multiple‐batch production

Multiple‐batch production is the most widely practiced method of raising channel catfish. Producers are increasingly adopting intensified production practices in multiple‐batch systems by increasing stocking density and aeration rates as a means to improve cost efficiencies. Proven stocking recommendations are required for the efficient implementation of recent developments in multiple‐batch production. Twelve 0.4‐ha ponds were understocked with 17,484, 20,612, and 26,124 fingerlings/ha (mean weight = 40 g/fish) over equal weights of carryover fish (0.46 kg/fish @ 4,589 kg/ha). Fish were fed once daily to apparent satiation with a 28% protein floating feed and aerated with a single 7.4‐kW electric paddlewheel aerator. Density‐dependent significant differences were absent for gross, net, daily net yields, marketable yields (≥0.54 kg), growth (g/day), and survival. Sub‐marketable yield (<0.54 kg) and feeding rate increased significantly with increased understocking density. Economic analysis revealed increased breakeven prices and diminished net returns with increased stocking density when sub‐marketable fish were not considered as revenue. These differences in production costs and profits among the three treatments became minimal when sub‐marketable fish were included as revenue. All three density treatments attained positive annual net cash flows. This study validates channel catfish understocking densities of 17,000–26,000 fish/ha to improve cost efficiency in intensively aerated, multiple‐batch production systems.     

Effect of dietary Houttuynia cordata leaf meal and leaf extract on the growth performance,nutrient utilization and expression of IGF‐I gene in Labeo rohita

A 60‐day feeding trial was conducted to evaluate the effects of feeding Houttuynia cordata leaf meal and extract on the growth performance, nutrient utilization and expression of insulin‐like growth factor‐I (IGF‐I) in Labeo rohita fingerlings. Two hundred seventy fingerlings were randomly distributed in six experimental groups in triplicates. Six isonitrogenous (350 g/kg CP) and isocaloric (17 MJ/kg DE) diets were prepared with graded levels of leaf meal (LM) and leaf extract (LE), namely C (control, without LE and LM), LE‐0.25 (2.5 g/kg LE), LE‐0.5 (5 g/kg LE), LE‐1.0 (10 g/kg LE), LM‐1.0 (10 g/kg LM) and LM‐2.0 (20 g/kg LM). Significantly (p < 0.05) higher IGF‐I expression, weight gain %, specific growth rate and lower feed conversion ratio were observed in LM‐1.0 followed by LE‐1.0 group compared to control group. Higher protease activity was observed in LE‐1.0 compared to other experimental groups, while no significant changes were found for amylase and lipase activities. Compared to control, muscle alanine aminotransferase and aspartate aminotransferase activities were significantly higher in treatment groups except for LM‐2.0. These results suggest that either LE‐1.0 or LM‐1.0 can be supplemented in the diet to improve the growth of L. rohita. However, the supplementation of 10 g H. cordata leaf meal/kg feed can be the better option considering the cost of extraction.     

Relative status and contribution of sediment phosphorus and nitrogen in carp culture system fertilized with various combinations of rockphosphate

Growth performances of advanced fry of Indian major carps. Labeo rohita (Hamilton). Catla catla (Hamilton) and Cirrhinus mrigala (Hamilton), were examined in simulated pond systems using monthly application of the following fertilizers in six treatments: Mussoorie rockphosphate (MPR) in low (100 kg P₂O₅ ha^?1) and high doses (200 kg P₂O₅ ha^?1), single superphosphate (SSP) (50 kg P₂O₅ ha^?1), single superphosphate mixed with rockphosphate (1:1 by weight: 50 kg P₂O₅), compost (C) (water hyacinth and cattle manure) and composted rockphosphate (MPR-C). The amount of available P in surface sediment of MPR-C did not differ from that in either the SSP or the MPR + SSP treatment, whereas the total and available N contents differed greatly. There was an inverse relationship between the time to reach phosphate peak of water and the retention time of fertilizer in surface sediments. It is evident that total P of surface sediment was the most significant contributor to fish growth in exclusively MPR treatments, whereas total P and total N of surface sediments are involved in the MPR treatments in combination with compost or SSP.     

Microbial Phytase Supplementation in Rohu, Labeo rohita, Diets Enhances Growth Performance and Nutrient Digestibility

Abstract.— A feeding trial was conducted for 60 d to study the effect of dietary microbial phytase on growth performance and nutrient digestibility of rohu, Labeo rohita , fingerlings. One hundred and twenty fingerlings (average initial weight: 9.17 g/fish) were equally distributed into five experimental tanks, each with four replicates. Five isonitrogenous (35%) and isocaloric (16.79 kJ/g) diets were prepared from plant-based ingredients, supplemented with microbial phytase at the level of 0, 250, 500, 750, and 1000 U/kg diets and fed to T₀, T₁, T₂, T₃, and T₄ groups, respectively. Weight gain %, food conversion ratio, protein efficiency ratio, and apparent net protein utilization were significantly ( P  < 0.05) improved in groups fed phytase-supplemented diets compared to control, the highest being observed in T₃ group. Maximum apparent digestibility of phosphorus and crude protein was recorded in T₃ group. Bone ash, phosphorus (P), and calcium (Ca) contents were also significantly ( P  < 0.05) increased in phytase-fed groups. However, maximum was recorded in T₃ group. Results from the present study indicated that addition of 750 U microbial phytase/kg diets effectively improved nutrient utilization, bone mineralization, and hence growth of L. rohita fingerlings.     

Total sulphur amino acid requirement of the Indian major carp, Labeo rohita (Hamilton)

The quantitative dietary sulphur amino acid requirement of the Indian major carp, Labeo rohita (Hamilton), was determined by conducting a growth study. The experimental diets contained 400 g crude protein kg⁻¹ from casein, gelatine and supplemental crystalline amino acids. Diets containing six graded levels of methionine (3.2, 6.5, 9.0, 11.5, 14 and 16.5 g kg⁻¹) with a constant level of cystine (1.4 g kg⁻¹) were formulated and fed to triplicate groups of Labeo rohita fingerlings twice a day to satiation for 60 days. The optimum dietary requirement for methionine was estimated using the break-point regression analysis at 11.5 g kg⁻¹ of diet or 28.8 g kg⁻¹ of dietary protein. Thus the total sulphur amino acid (Met + Cys) requirement was determined to be 12.9 g kg⁻¹ of diet or 32.3 g kg⁻¹ of protein. Higher survival, specific growth rate and food conversion efficiency values were observed for fish fed the diet containing optimum levels of sulphur amino acids.     

Effect of pig dung on water quality and polyculture of carp species during winter and summer

Theeffect of pig dung, as pond manure [at 18 and 36 tha^–1 yr^–1] and as fish feed ingredient[replacing traditional diet composed of solvent extracted rice bran and mustardcake (1:1) at 25, 50, 75 and 100% levels], was observed on water quality, pondproductivity and survival and growth of carp in polyculture system during winter(12–18 °C) and summer (18–36 °C)months. The studies on water quality parameters viz pH, dissolved oxygen andalkalinity revealed that pig dung even at higher levels (both as manure and /oras feed ingredient) did not deteriorate the quality of water, as all the waterparameters remained within the optimum ranges required for carps. The nutrient(phosphates and nitrates) status of water was significantly better in pondsreceiving pig dung as pond manure at 36 tha^–1 yr^–1. Pond productivity in terms ofplankton production (phyto and zooplankton) was also significantly higher innutrient rich water (36 tha^–1 yr^–1) both during winter andsummer. Further, in all the ponds (including control) phytoplankton levels weresignificantly higher during winter and zooplankton was higher during summer. Thestudies revealed 100% survival of all the fish species in all the treatments.During winter, the growth of carp was higher in treatments where pig dung wasused as feed ingredient (at 25% level), whereas during summer growth was higherwhere pig dung was used either as pond manure and/or as feed ingredient (athigher levels). Further, among carps, the growth of Indian major carps vizCatla catla, Labeo rohita and Cirrhinamrigala was higher during summer and that of exotic carps vizCyprinus carpio and Ctenophayrengodonidella was higher during winter.     

The Costs and Effects of Alternative Winter Feeding Strategies for Channel Catfish Ictalurus punctatus in Multiple-Batch Production

Previous work suggested that feeding catfish, Ictalurus punctatus, more frequently over the winter might reduce weight loss. Twelve 0.10-ha ponds were stocked with 987 kg/ha market-sized fish and 2,960 kg/ha sub-marketable fish in November 2008 with treatments of: (1) unfed, (2) fed daily (fed 90 d), and (3) temperature-threshold feeding (fed 62 d). Total gross yield was significantly greater for the temperature-threshold feeding treatment than the unfed control, but survival and mean weight of fish at harvest were not. Net yield was negative for all treatments, due primarily to mortality of market-sized fish. Plasma glucose and insulin-like growth factor-1 did not differ significantly, but plasma osmolality was significantly lower in fasted than in fed fish. Mean feed consumption rates in vats provided evidence to support more frequent feeding over the winter. Overwintering costs were $0.11/kg with temperature-threshold feeding. Research on strategies to reduce winter mortality has potential to reduce overwintering costs.     

Effect of dietary L-carnitine supplements on growth and body composition of fingerling rohu, Labeo rohita (Hamilton)

Rohu, Labeo rohita (Ham.), fingerlings (average wt 3.38 g) maintained in 25 m² cement tanks were fed fish-meal-based, 300 g kg⁻¹ protein diets containing different levels (0, 0.25, 0.5, 0.75 and 1.0 g kg⁻¹) of L -carnitine in triplicate over a period of 126 days. Fish that received 0.5 g kg⁻¹ carnitine showed significantly higher growth than those fed the basal diet or the rest of the carnitine diets. Fat digestibility, food conversion efficiency and protein efficiency ratio were better in carnitine-fed fish; however, viscerosomatic and hepatosomatic indices decreased. Muscle proximate composition was affected as a result of carnitine treatment. The results of the present study demonstrate a positive effect of carnitine on the growth and body composition of rohu.     

Immunological response of the Indian major carps to Aeromonas hydrophila vaccine

Abstract. Fingerlings of the three major types of Indian carp, i.e. Catla catla (Hamilton), Labeo rohita (Hamilton) and Cirrhunas mrigala (Hamilton), were immunized using a haemolysin-negative mutant of Aeromonas hydrophila . Very high titres of antibodies were induced in C. catla , followed by C. mrigala and L. rohita . Immunized fish showed good protection against homologous challenge. Moderate protection against heterologous challenge was observed in C. mrigala and L. rohita .     

Intensive polyculture of common carp (Cyprinus carpio L.) and herbivorous fish [silver carp, Hypophthalmichthys molitrix (Val.), and grass carp, Ctenopharyngodon idella (Val.)]

Intensive polyculture of common carp and herbivorous fish (silver carp and grass carp) at high stocking densities and with intensive feeding with fodder and mineral and organic fertilization was carried out without mechanized aeration and automated feeding.Two stocking patterns were tested. The first, in Pond 1 (with an area of 2.5 ha), had the following stocking rates: one-year carp (C₁), 8000 fish/ha; one-year silver carp (S₁), 1500 fish/ha; and one-year grass carp (G₁), 200 fish/ha. The yield was 6292 kg/ha of standard consumer fish (C₁₊ 743 g, S₁₊ 944 g, and G₁₊ 1000 g) at a relatively low food conversion ratio (2.24) and high survival of all fish. Within the total yield, the two-year carp contributed 76%, the silver carp 21%, and the grass carp 3%. The second stocking pattern, in Pond 2 (0.25 ha), had the following rates: C₁, 8500 fish/ha; S₁, 2000 fish/ha; and G₁, 200 fish/ha, and produced a still higher total yield (6629 kg/ha) at a relatively low food conversion ratio (2.10). The two-year carp in Pond 2 contributed 88% of the total yield, and the herbivorous fish only 12% even though they accounted for 20% of the stock.Our results (Pond 2) are compared with other record yield experiments under similar conditions but including tilapia. At a total stocking rate of 10 700 fish/ha and without participation of tilapia, over a period of 186 days (as against 126 days in the other experiment), our experiments gave a total yield which was 347 kg/ha higher at a food coefficient 15% lower. The growth period was 60 days longer in our experiments but it included April and October when water temperature is much below the optimum and only 4% of the total amount of fodder was assimilated.     

Evaluation of a Barrier Confinement System for Channel Catfish,Ictalurus punctatus,Production

An in‐pond confinement system to separate channel catfish, Ictalurus punctatus, by size within a single pond provides an opportunity for improved growth of understocked fish in ponds with larger market‐sized fish. A barrier of polyvinyl chloride–coated galvanized wire mesh was constructed in five 0.10‐ha earthen ponds to partition the pond into one‐third and two‐third sections, while five other 0.10‐ha ponds were left as traditional open ponds for a control. To evaluate catfish performance in this confinement system, fingerlings (25 g) were stocked at 14,820/ha into the smaller one‐third section of the barrier and carryover fish (408 g) at 2580 kg/ha into the larger two‐third section of the barrier. The control ponds were stocked with the same sizes and numbers of fish in a traditional earthen pond without a barrier. Yield, survival, feed conversion ratio (FCR), growth, and economics were compared between treatments. Fingerling yields were greater in the barrier system that allowed fingerlings to be separated physically from larger carryover fish. There were no differences in yield of carryover fish, survival, FCR, or growth between the control and the barrier ponds. Partial budget analysis revealed a positive net change of $367/ha or $38,125 for a 104‐ha catfish farm (at a market price of $1.54/kg of additional stockers produced). The value of the greater weight of understocked fish produced in the barrier system was greater than the annualized cost of installing the barrier, for farmers raising fish in multiple batch. Thus, on an experimental basis, the confinement system was economically profitable; however, trials on commercial farms are needed to evaluate performance on a larger scale.     

A new high in fish production in India with record yields by composite fish culture in freshwater ponds

Composite fish culture of the Indian major carp, Catla catla, Labeo rohita and Cirrhinus mrigala together with the Chinese silver carp Hypophthalmichthys molitrix and grass carp Ctenopharyngodon idella and the Indonesian strain of common carp (Cyprinus carpio communis) was carried out in experimental ponds in 1971–1972 and 1973–1974. The management techniques adopted aimed at high yields of marketable fish (around 1 kg) in 1 year.In the first year, production varied from 3 889 to 5 600 kg/ha/year and this rose to an average of 8 200 kg/ha/year with a maximum of 9 389 kg/ha/year in the second year. The important changes made to the management schedule in 1973 were increased stocking density, greater use of feed and fertilizers, and provision of more weeds for grass carp.The experimental studies demonstrate the practicability of raising large crops of healthy marketable fish in India.     

Evaluation of Growth,Survival, and Production of an Endangered Fish,Labeo gonius (Hamilton) Fingerlings in Earthen Nursery Ponds

ABSTRACT

Nursery rearing of an endangered fish, Labeo gonius (Ham.) was studied in relation to varying stocking densities in earthen ponds. The experiment was conducted for 8 weeks in nine nursery ponds having an area of 0.012 ha with an average depth of 1 m. Four-day-old hatchling stocked at 0.6 million/ha was designated as treatment-1 (T₁), 0.8 million/ha as treatment-2 (T₂) and 1.0 million/ha as treatment-3 (T₃), respectively. At stocking, all hatchlings were of same age group with a mean length and weight of 0.66 ± 0.08 cm and 0.001 ± 0.0001 g, respectively. Hatchlings in all the experimental ponds were given wheat flour for the first 7 days, finely ground mustard oilcake for the next 7 days and a mixture of rice bran, and mustard oilcake (1:1) for days 15 to 56. The rate of feeding was 20 kg/million hatchling/day for the first two weeks, 25 kg for the second two weeks, 30 kg for the third two weeks and 35 kg for the fourth two weeks. The physicochemical parameters of water and plankton were monitored simultaneously and were within the acceptable range for fish culture. Growth parameters (final weight, final length, weight gain, length gain and specific growth rate) and survival of fingerlings were significantly higher in T₁ (0.6 million hatchling/ha) than those in T₂ (0.8 million/ha) and T₃ (1.0 million/ha), respectively. Feed conversion ratio (FCR) was significantly lower in T₁ followed by T₂ and T₃ in that order. The estimated gross and net productions of fingerlings were significantly higher in T₁ than in T₂ and T₃, respectively. Significantly higher number of fingerlings was produced in T₃ than those in T₂ and T₁. Despite this, consistently higher net benefits were obtained from T₁ than from T₃ and T₂. Overall, highest growth, survival, production and benefits were obtained from T₁ where stocking density of hatchlings was 0.6 million/ha. Hence, of the treatments evaluated, stocking density of 0.6 million hatchling/ha appears to be the most efficient stocking density for rearing of L. gonius fingerlings in earthen nursery ponds.     

Improved Utilization of Pond Carrying Capacity by Increasing Initial Stocking Rates and Subsequent Stock Division1

Fingerling channel catfish Ictaturus punctarus were stocked into eight 0.04-ha ponds at 12,500 fishlha (treatment 1) and 50,000 fish/ha (treatment 2) with four ponds per treatment. At the end of of phase I (59 d) 50% of the fish were removed from each of the ponds in treatment 2 and divided equally into two ponds, forming treatment 3 (eight ponds at a density of 12,500 fish/ha). The remaining fish in treatment 2 (25,000 fish/ha) were maintained in the original ponds until the end of phase II (36 d). At this time, the fish were removed and equally divided at a density of 12,500 fish/ha into separate ponds. These ponds were continued to be denoted as treatment 2. All fish were grown for a total of 188 d. Production characteristics between treatments were compared at phases and at the end of the 188 d. There was no significant difference in feed conversion ratios due to treatment. The individual weights of the fish were higher in treatment I, but the difference occurred only in phase I. Size variabilities in treatments 2 and 3 were also higher than in treatment 1, which may cause a decrease in the percentage of marketable fish. Although there were some adverse effects due to the initial high stocking densities, overall pond production was higher in treatments 2 and 3. Treatment 2 had a daily net production of 49.9 ± 3.43 kg/ha and treatment 3 had 44.6 ± 3.81 kg/ha per d, compared to treatment 1 with only 32.4 ± 1.06 kg/ha per d (mean ± SD).