Concrete Ponds Research Articles

The effect of different growing conditions to proximate composition and fatty acid profiles of rainbow trouts (Oncorhynchus mykiss)

ABSTRACTThe experiment was carried out using escaped rainbow trout (weights between 268 and 310 g) caught in Seyhan Dam Lake, Adana, Turkey and three groups of rainbow trout (weights between 226 and 277 g) cultured in concrete freshwater ponds, in freshwater cages in Seyhan Dam Lake and in marine cages in Black Sea by private companies. Proximate composition and the fatty acid profiles of the fishes were determined. Analysis of the proximate composition of the present study revealed that the escaped rainbow trout flesh to have the highest water (74.23%) and the lowest lipid (4.47%) content while lowest level of moisture and highest levels of lipid was observed in farmed fish in ponds (68.69% and 7.78%). According to the results of fatty acid analysis, the highest saturated fatty acid (31.3%) and the lowest polyunsaturated fatty acids (PUFA) (26.51%) levels were in the escaped group obtained from wild, while PUFA levels were higher in the cultured groups. On the other hand, the levels of n3/n6 ratio were higher in escaped and marine cages groups (2.71 and 2.58) than in ponds and Dam Lake cages groups (1.75 and 1.33). According these results, rainbow trout from all groups studied are a desirable food item for human consumption.

Acoustical deterrence of Silver Carp (Hypophthalmichthys molitrix)

The invasive Silver Carp (Hypophthalmichthys molitrix) dominate large regions of the Mississippi River drainage and continue to expand their range northward threatening the Laurentian Great Lakes. This study found that complex broadband sound (0–10 kHz) is effective in altering the behavior of Silver Carp with implications for deterrent barriers or potential control measures (e.g., herding fish into nets). The phonotaxic response of Silver Carp was investigated using controlled experiments in outdoor concrete ponds (10 × 4.9 × 1.2 m). Pure tones (500–2000 Hz) and complex sound (underwater field recordings of outboard motors) were broadcast using underwater speakers. Silver Carp always reacted to the complex sounds by exhibiting negative phonotaxis to the sound source and by alternating speaker location, Silver Carp could be directed consistently, up to 37 consecutive times, to opposite ends of the large outdoor pond. However, fish habituated quickly to pure tones, reacting to only approximately 5 % of these presentations and never showed more than two consecutive responses. Previous studies have demonstrated the success of sound barriers in preventing Silver Carp movement using pure tones and this research suggests that a complex sound stimulus would be an even more effective deterrent.

PREDICTING THERMAL PERFORMANCE OF ROOFING SYSTEMS IN SURABAYA

Traditional roofing systems in the developing country likes Indonesia are still be dominated by the 30o, 45o, and more pitched angle roofs; the roofing cover materials are widely used to traditional clay roof tiles, then modern concrete roof tiles, and ceramic roof tiles. In the 90’s decay, shop houses are prosperous built with flat concrete roofs dominant. Green roofs and roof ponds are almost rarely built to meet the sustainable environmental issues. Some tested various roof systems in Surabaya were carried out to observe the roof thermal performances. Mathematical equation model from three references are also performed in order to compare with the real project tested. Calculated with equation (Kabre et al.), the 30o pitched concrete-roof-tile, 30o clay-roof-tile, 45o pitched concrete-roof-tile are the worst thermal heat flux coming to room respectively. In contrast, the bare soil concrete roof and roof pond system are the least heat flux streamed onto room. Based on predicted calculation without insulation and cross-ventilation attic space, the roof pond and bare soil concrete roof (greenery roof) are the appropriate roof systems for the Surabaya’s climate; meanwhile the most un-recommended roof is pitched 30o or 45o angle with concrete-roof tiles roofing systems.

Estimation of Length-Weight Relationship and Proximate Composition of Catfish (Clarias gariepinus Burchell, 1822) from Two Different Culture Facilities

This study was carried out to determine and compare the proximate composition and length weight relationship of C. gariepinus from two culture systems (earthen and concrete ponds). The fish samples were collected from three fish farms with same cultural condition in different areas of Obio-akpor Local Government Area of Rivers State, Nigeria. Result on the length- weight relationship revealed that C.gariepinus reared in concrete tank had a total length of 15.50- 49.00cm with a mean of 32.71cm and weight of 150-625g, while total length of C. gariepinus reared in the earthen pond ranged from 19.90-58.0cm with a mean of 39.8cm and weight of 195-825g. The T- test shows that the total length of earthen pond were significantly higher than the concrete tank and the weight in the earthen pond was significantly higher than the concrete tank. Parameters of proximate composition analysed were moisture, protein, lipid, carbohydrate, ash and fiber from the fish flesh. Protein content showed a significantly higher in the earthen ponds than the concrete tanks. Ash contents varied from 1.5±1.66-7.4±0.67% in the concrete tanks and were significantly higher than the earthen ponds which ranged from 3.1±0.94-4.5±2.11%. Lipid was significantly higher in earthen ponds than concrete tanks. Generally, the two culture systems have a significant influence on length–weight relationship and nutritional value of C. gariepinus. However, C. gariepinus reared in concrete tank had a heavier body weight than earthen pond and also C. gariepinus reared in earthen pond had highest nutritive values than the concrete tank.

Influence of alum on cyanobacterial blooms and water quality of earthen fish ponds.

Eruption of blue-green algal blooms occurs frequently in eutrophic lakes and fish ponds, with associated unpleasant odor and horrid scums. In the present study, we conducted a pre-test experiment in 3 m(3) outdoor concrete ponds to determine the optimum concentration of aluminum sulfate (alum) required for reduction of the cyanobacterial blooms without negative effect on fish growth. As a consequence, 10 mg L(-1) alum was named as the optimum concentration that was applied in 1000 m(3) earthen fish ponds. Obtained results showed that Secchi disc values significantly increased from 10 to 24 cm after 14 days of alum application. Alum-treated ponds showed a reduction in total phytoplankton counts by 94 and 96% compared to the corresponding controls after 10 and 14 days, respectively. Abundance of blue-green algae in the treated ponds was decreased by 98% compared to the corresponding control after 14 days of alum application. Consequently, dissolved oxygen, pH, total phosphorus, orthophosphate, and chlorophyll "a" content declined significantly. Our study revealed that using 10 mg L(-1) of alum is an effective way to control cyanobacterial blooms in eutrophic waters, especially in fish ponds, without negative effect in water quality.

Effects of inulin and Jerusalem artichoke (Helianthus tuberosus) as prebiotic ingredients in the diet of juvenile Nile tilapia (Oreochromis niloticus)

Abstract This study evaluated the prebiotic effects of dietary inulin and Jerusalem artichoke tuber (JA) on juvenile Nile tilapia ( Oreochromis niloticus ). Five dietary treatments (each diet in four replicates) were formulated to incorporate inulin at 0 (control), 2.5 and 5 g kg −1 and JA at 5 and 10 g kg −1 . Fish were reared in concrete ponds for 8 weeks. Fish fed the inulin diets exhibited better growth performance than fish fed the control diet, and fish fed the JA diets had the best growth performances among all diets tested. Dietary inulin and JA increased red blood cell number. Among the fourteen blood chemicals examined, dietary inulin or JA led to increased glucose, albumin, protein, magnesium, calcium, and iron content ( P −1 improved lysozyme activity and alternative complement haemolytic 50 (ACH50) activity. Dietary JA increased total immunoglobulin content, lysozyme activity, and ACH50 activity. Dietary inulin or JA increased the height of intestinal villi and goblet cell number. These findings indicate that inulin at 5 g kg −1 had beneficial prebiotic effects on juvenile Nile tilapia and that direct supplementation with JA at 10 g kg −1 had positive effects on growth and health. Thus, both inulin and JA have great potential for use as prebiotics in fish feed.

Production of recombinant great sturgeon (Huso huso, Linnaeus, 1758) growth hormone (GH) by Pichia pastoris (Guillierm, 1956)

In this research, the encoding cDNA of growth hormone (GH) was cloned from the pituitary gland of great sturgeon Huso huso (three adults: two females and one male, 7–9 years old, 70–90 kg, reared in concrete ponds). In order to obtain the great sturgeon recombinant GH expression in Pichia pastoris, the mature encoding cDNA was first cloned in TA vector PTZ57R and then sequenced. After confirmation of the correct GH sequence, the GH coding sequence was subcloned into pHILS1 expression vector. The yeast Pichia pastoris GS115 strain was transformed with the expression plasmid. Results obtained from this study showed that great sturgeon GH recombinants were expressed upon induction with methanol and exported into the medium. The level of expression was examined using RNA analysis, SDS-PAGE, and western blot analysis. RNA analysis of the recombinant strains showed a sharp, specific band in 800 bp. The specific band in transformants indicated the presence of GH RNA in the yeast. SDS-PAGE and western blot analysis showed a specific 21 kDa band for the growth hormone. Culture conditions were optimized for pH = 6 and incubation time (after 24 h induction, peaking at 72 h) for maximal protein production. The results provide useful information for the future production of recombinant growth hormones in other sturgeon species.

Effects of dietary protein and lipid levels on growth, feed utilization, body and plasma biochemical compositions of hybrid grouper (Epinephelus lanceolatus ♂×Epinephelus fuscoguttatus ♀) juveniles

Abstract An 8-week growth trial was conducted to determine the effects of dietary protein and lipid levels on growth, feed utilization, body and plasma biochemical compositions of hybrid grouper ( Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀ ) juveniles. Twelve experimental diets with the same estimated gross energy (360 kcal per 100 g dry matter) were formulated to contain 40%, 45%, 50%, or 55% dietary crude protein (CP) level (dry-matter basis) together with either 7%, 10%, or 14% dietary crude lipid (CL) level, being abbreviated as P40/L7, P45/L7, P50/L7, P55/L7, P40/L10, P45/L10, P50/L10, P55/L10, P40/L13, P45/L13, P50/L13 and P55/L13, respectively. Juvenile fish (average initial weight of 4.68 ± 0.05 g/fish) were stocked as groups of 22 fish in floating cages (L 120 cm × W 70 cm × H 50 cm) placed in indoor 6-m 3 concrete ponds with continuous sea water flow (salinity: 33.1 g/L). From week 1 to week 8, fish in triplicate cages were fed each dietary treatment at rates of 9%, 7%, 5%, 5%, 4%, 4%, 3% and 3% of body weight (BW)/day, respectively. Weight gain (WG) of hybrid grouper fed the diet with 40% crude protein was significantly lower (P

English

The microbial profile of some concrete and earthen fish ponds within the Niger delta region was evaluated. The results of physico-chemical properties of the water samples showed that alkalinity values were significantly higher in concrete ponds (99.7±47.1 to 150±69.7) than (18±6.9 to 24±14.5 mg/L) in earthen ponds. Electrical conductivity values varied significantly between the ponds with (200±84.1 to 290±74.9 µs/m) in concrete ponds and (18±6.9 to 24±14.5 µs/m) in earthen ponds. Sulphate concentrations were higher in concrete ponds (0.25±0.36 to 1.53±14.9 mg/L) than (0.25±0.36 to 0.4±0.77 mg/L) in earthen ponds. The mean total heterotrophic bacteria count was higher in concrete ponds (6.5×105 to 7.4×105 cfu/ml) than in earthen (6.3×105 to 6.5x105 cfu/ml) ponds. The mean fungal count ranged from 2.11×105 to 2.25×105 cfu/ml in concrete pond and (1.8×105 to 2.4×105 cfu/ml) in earthen ponds. The bacterial genera isolated from the ponds were Escherichia coli, Staphylococcus sp., Aeromonas sp., Streptococcus sp., Salmonella sp., Vibrio sp., Shigella sp., Proteus sp., Pseudomonas sp., Klebsiella sp. Enterobacter species occurred only in concrete pond, while Serratia species occurred in earthen ponds. The fungal genera isolated from both the concrete and earthen ponds were Aspergillus sp., Penicillum sp. and Cladosporium sp. The genera, Fusarium sp. and Mucor sp were isolated only from earthen ponds. The study revealed that the ponds were grossly contaminated with pathogenic microorganisms which poses a risk to human health, thus of significant public health concern. Key words: Heterotrophic bacteria, fish ponds, fungal isolates, pathogens, physico-chemical properties.

Normal haematological and blood biochemistry values of cultured Clarias gariepinus in Southeast, Nigeria

This study investigated the normal haematological and blood biochemistry profile of apparently healthy sharp-tooth catfish (Clarias gariepinus) raised in concrete ponds in Southeast, Nigeria. A total of 28 fish of two age ranges and equal sexes were used, and determination of haematological and blood biochemistry profiles followed standard procedures. Results obtained for the parameters assessed for the young adults and adults are summarized as follows: mean ± standard error: packed cell volume—31.22 ± 0.96 and 35.89 ± 1.44 %, haemoglobin concentration—11.24 ± 0.40 g/dl and 11.35 ± 0.26 g/dl, red blood cell count—2.47 ± 0.03 × 106/μl and 2.45 ± 0.05 × 106/μl, mean corpuscular volume—125.43 ± 4.52 fl and 142.12 ± 2.11 fl, mean corpuscular haemoglobin—45.83 ± 1.72 and 45.60 ± 1.44 pg, mean corpuscular haemoglobin concentration—35.00 ± 1.34 and 31.94 ± 1.00 g/dl, white blood cell count—18.52 ± 0.69 × 103/μl and 28.33 ± 1.64 × 103/μl, alanine amino transferase—37.52 ± 0.87 and 39.58 ± 0.17 IU, aspartate amino transferase—54.77 ± 0.22 and 50.52 ± 0.44 IU, alkaline phosphatase—5.29 ± 0.51 and 8.65 ± 0.66 IU, plasma blood glucose—141.67 ± 10.62 and 164.00 ± 11.97 mg/dl, total proteins—1.74 ± 0.06 and 3.55 ± 0.13 g/dl, albumin—0.81 ± 0.04 and 1.23 ± 0.04 g/dl, globulin—0.94 ± 0.07 and 2.21 ± 0.12 g/dl, calcium—4.41 ± 0.40 and 9.34 ± 0.53 mg/dl, total cholesterol—65.70 ± 4.06 and 161.95 ± 15.50 mg/dl, blood urea nitrogen—1.78 ± 0.22 and 0.98 ± 0.13 mg/dl, body weight—245.00 ± 11.67 and 675.00 ± 43.31 g. Results obtained showed significant (p 0.05) between the sexes in all the parameters assessed except the young adult males that have significantly (p < 0.05) higher mean bodyweight than their female counterparts and adult females that have significantly higher mean total cholesterol than the males. Data generated from this study were considered important tools for diagnosis of diseases, for monitoring of therapeutic interventions and for prognostic values in diseases of this species.

Development of aquaculture on Сhirkeyskoe reservoir in the republic of Daghestan

In the article is given the description of Chirkeyskoe reservoir located in the republic of Dagestan. Are shown the prospects for development and the results of researchers on the organization of market salmon and sturgeon aquaculture. The unique experience of the use of the not specialized concrete ponds for the cultivation of trout and hybrids of sturgeon with the year-round feeding is presented.

Ecto-parasites Infestation of Nile Tilapia (&lt;i&gt;Oreochromis niloticus&lt;/i&gt;) in Concrete Ponds in Tamale, Ghana

The demand of concrete pond culture in the Northern Ghana is increasing. The safety and health of Nile tilapia produced in concrete ponds is of public concern. The study was to investigate the prevalence and mean intensities of ecto-parasites on the gills, skin mucus and the fin of Nile tilapia ( Oreochromis niloticus ) in some concrete ponds in Tamale, Northern Ghana. Two hundred and forty (240) randomly sampled specimens of comprising fingerlings, juveniles and adult fish of Nile Tilapia were examined using microscope and hand-held lens from November, 2013 to April, 2014 for ecto-parasites. Thirty five (35) of the specimens examined were infested with ecto-parasites representing 15% prevalence during the study period. The prevalence rate encountered was Ichthyophthirius multifilis (60%) ≥; Trichodina sp (23%) ≥; monogeneans (17%). Out of 155 fingerlings examined, 14.8% were infested while 85 adult fish examined had 14.1% infested with ecto-parasites. The mean intensity of Trichodina spp ranged from 0 to 2.5. Monogeneas and Ichthyophthirius multifilis mean intensity ranged from 0 to 1.7. Physico-chemical characteristics of the pond were suitable for culture. The mean temperature was 28.48 o C ± 2.31, the mean value for dissolved oxygen was 4.32 mg/l ± 0.38, the mean pH was 6.17 ± 0.23 and mean nitrate was 30.60 ppm ± 1.0286. The low prevalence and intensities of ecto-parasites recorded indicates that with good water quality, ecto-parasites may not pose a threat to O. niloticus production in concrete pond.

Culture Mixed-Sex and Monosex of Tilapia in Ponds in Mexico City

In this study, the growth of Oreochromis niloticus both mixed sex and males sexually reversed were analyzed in concrete ponds in the FES Zaragoza, UNAM, under the environmental conditions of the Mexico City. The experiment was carried from May to November 2013, in two concrete ponds of 50 m2. Similar feeding regime and stocking density of fish were maintained for the culture systems. Different growth parameters like body weight, length, daily weight gain (DWG), specific growth rate (SGR), feed conversion rate (FCR), Fulton’s condition index (K) and survival were analyzed during six months culture period. It was found that culture with monosex males tilapias yielded the highest weight, length, DWG and SGR compared to mixed sex populations tilapias. Water quality was monitored along the experiment. Based on the results, there were statistically significant differences in size (W = 20942.5, p 5 mg/L), warm water (>20°C), productive ( 8). Acceptable growth of fish and a yield of 3 ton/ha/6 months were obtained in both two ponds; therefore, the culture of tilapia under conditions of Mexico City was recommended.

Pathological alterations due to motile Aeromonas infection in red swordtail fish (Xiphophorus helleri).

A herd of red swordtail fish (Xiphophorus helleri) was reared in outdoor concrete ponds and suffered from occasional mortality. Moribund fishes showing abdominal dropsy and fin rots were sent for diagnosis. Gross necropsy findings showed enlargement of liver, spleen, and kidney in concurrence with congestion, and a severe accumulation of peritoneal fluid. Histopathological findings revealed an alteration of hepatocytes, with a severe diffuse accumulation of fat vacuoles in the cytoplasm. In the trunk kidney, severe accumulation of mononuclear cells together with cloudy swelling of the renal tubular epithelium was observed. From internal organs of the fish motile Aeromonas spp. were identified. The pathological findings might be associated with a long-term infection of affected fish fostered by common stressors such as improper feeding and poor pond environment condition (water temperature). Effective therapeutic measures comprised an advancement of keeping conditions and appropriate feeding to improve the health status in combination with the application of antibiotic substances.

Impacts of Hill Torrents’ Management on Socio-Economic Conditions of Arid Land Farmers: a Case Study of Tehsil D.G. Khan

The study conducted in arid areas of Dera Ghazi Khan occasionally affected by hill torrents (Suri-Lund, Vidore, Sakhi-Sarwar, Mithawan) coming from Koh-e-Suleman range. The study found that hill torrent water is used for agriculture, domestic and livestock. The management of this water significantly affects on income, crop yield, soil fertility, health conditions and living standard of farmers. The local cost effective methods to store this water include wah, dubba and bundh but most of water is wasted as they are insufficient. The water distribution mechanism fosters cooperation and helps to form new relations with co-farmers. The study suggested that government and NGOs should help people to construct concrete diversions, bundhs, ponds and dams to manage hill torrent water.

Influence of Protein Levels and Pond Fertilization during Broodstock Pre-Spawning Period on the Tolerance of Nile Tilapia, Oreochromis niloticus, Fry to Winter Season Temperature

Nile tilapia, Oreochromis niloticus females were fed three commercial diets (20, 25 and 30% crude protein) in 200 m3 earthen ponds fertilized with compost at rate of 25 kg/pond/week to evaluate their growth performance, seed production and survival rate of produced fry throughout winter season. Average initial body weight of females (19.30±1.05g) and males (23.45±2.1g) were stocked separately with density of 1000 fish/pond, and fed to satiation twice daily for 120 days as a pre-spawning period. Both sexes were then transferred to concrete ponds in hothouses with a ratio (6:2 females: male) per tank. During spawning period, broodstocks were fed a diet (25% crude protein) at 1% of their live body weight for 90 days. Last batch of produced fry were nursed in concrete tanks in hothouses, and fed on 30% crude protein diet for 45 days. Fry from each treatment was then transferred to wintering ponds, stocked at 500 fry/m3, and fed twice daily tosatiation for 120 days. Results indicated that final body weight, gain and average daily gain of broodstocks increased significantly (P<0.05) with increasing dietary protein level in fertilized ponds. Feed conversion rate and protein efficiency ratio improved, but insignificantly with increasing dietary protein level and with adding fertilizers. However,number of progeny increased significantly (P<0.05) by increasing protein level in fertilized ponds. Correspondingly, initial and final body weight of the offspring was significantly (P<0.05) triggered with increasing protein level and fertilizers. Also, feed conversion rate of fry improved significantly (P<0.05) with increasing dietary protein level and fertilized treatments. Moreover, survival of fry increased significantly (P<0.05) with fertilization treatments and increasing protein level. Therefore, the study highlights that by feeding O. niloticus broodstocks diets containing 25% crude protein supplemented with compost fertilizers during pre-spawning period, could be sufficient to trigger the production of viable fry that might tolerate low winter season temperatures.

High Infestation by Dawestrema cycloancistrioides in Arapaima gigas Cultured in the Amazon Region, Peru.

The aim of this study was to evaluate the presence of Dawestrema cycloancistrioides in semi-intensive fish farming of fingerlings of Arapaima gigas. Between September and November 2013, 60 individuals of A. gigas born in captivity, were collected in three concrete ponds, from a semi-intensive fish farm in the Peruvian Amazon. For the study of sclerotized structures, parasites were fixed in a solution of ammonium picrate glycerine and mounted in Canada balsam. To visualize internal structures, parasites were fixed in hot formaldehyde solution (4%) for staining with Gomori's trichrome. The parasitic indexes calculated were prevalence, mean intensity, and mean abundance. This study identified a high infestation of a monogenean D. cycloancistrioides in gills of A. gigas. The prevalence was 100%. The mean intensity and mean abundance of the parasite were 144.9 of parasites per individual. This study confirms the necessity of constant monitoring of fish in order to reduce fish mortality.

Normal haematological and blood biochemistry values of cultured Heteroclarias hybrid in South East Nigeria

This study investigated the normal haematological and blood biochemistry profile of apparently healthy cultured hybrid catfish Heteroclarias reared in concrete ponds in South East Nigeria. A total of 20 fish of two age ranges and equal sexes were used, and determination of haematological and blood biochemistry profile followed standard procedures. Results obtained for the parameters assessed for the young adults and adults respectively are summarized as follows (mean ± standard error): packed cell volume, 32.50 ± 1.10 and 37.33 ± 0.75 %; haemoglobin concentration, 11.81 ± 0.45 and 13.00 ± 0.21 g/dl; red blood cell count, 3.14 ± 0.07 × 106 and 3.09 ± 0.07 × 106/μl; mean corpuscular volume, 103.44 ± 3.13 and 122.82 ± 3.97 fl; mean corpuscular haemoglobin, 37.65 ± 1.50 and 42.35 ± 1.47 pg; mean corpuscular haemoglobin concentration, 37.11 ± 1.12 and 33.97 ± 0.47 g/dl; white blood cell count, 18.39 ± 1.04 × 103 and 20.92 ± 0.67 × 103/μl; alanine amino transferase, 30.90 ± 0.18 and 38.17 ± 0.16 IU; aspartate amino transferase, 54.20 ± 0.22 and 50.29 ± 0.25 IU; alkaline phosphatase, 5.00 ± 0.54 and 9.55 ± 0.74 IU; total proteins, 2.20 ± 0.07 and 4.05 ± 0.10 g/dl; albumin, 0.96 ± 0.03 and 1.38 ± 0.04 g/dl; globulin, 1.22 ± 0.07 and 2.70 ± 0.10 g/dl; plasma blood glucose, 94.17 ± 8.16 and 175.89 ± 10.38 mg/dl; total cholesterol, 85.33 ± 4.34 and 153.14 ± 8.63 mg/dl; calcium, 4.80 ± 0.48 and 11.64 ± 0.41 mg/dl; blood urea nitrogen, 1.24 ± 0.27 and 1.03 ± 0.13 mg/dl; and body weight, 287.50 ± 8.18 and 711.11 ± 36.11 g. Results obtained showed significantly higher (p 0.05) due to sex in all the haematological and blood biochemistry parameters assessed. Data generated from this study was considered important as deviations in the normal haematology and blood biochemistry values have a predictive value for general pathological and specific organ changes in the body.

English

This study analysed the profitability of small-scale catfish farming in Kaduna State, Nigeria. Sixty respondents were randomly selected and interviewed using interview schedule to elicit information through multi-stage sampling technique. The data were analysed using frequency, percentages, mean, and ranking while budgetary analysis (gross-margin) was used to determine the profitability of catfish farming. The result shows that majority (70%) used the concrete pond of an average of 200 m2. The source of their capital was mainly from personal savings (48.3%). The quantity of fingerlings raised ranges from 500-6000 at 20 fingerlings/m2. Majority (55%) of the respondents raised between 3000 and 6000 fish per cycle at 6 to 8 tons/ha-1 year-1. Quantity of fish raised and consumed had contributed positively to respondents’ household income. However, savings from catfish farming has contributed about 20 to over 75% of the total income of the respondents. The result of profitability reveals that respondents had an average of about ₦774,223.05 and net gross percentage of 73.4% per production cycle. Inadequate capital, scarcity of fingerlings, and inadequate extension services were the major problems facing catfish farmers. The study recommended that catfish farmers should be encouraged to form and manage functional cooperatives as a way to pool their resources for individual development within the fish farming industry. Also, the government should subsidize the prices of input used in fish farming. Key words: Fish farming, catfish, profitability, Kaduna State.

Water quality and production performance of catfish–prawn co-culture with organic carbon source addition

The objective of this study was to determine the effects of prawn juveniles and organic carbon source on the water quality and production performance of catfish. The experiment consisted of three treatments in triplicates, i.e. catfish monoculture as the control (treatment A); catfish–prawn co-culture at a prawn density of 20 prawn/m2 (treatment B) and catfish–prawn co-culture at a prawn density of 40 prawn/m2 (treatment C). Catfish was reared in a bamboo cage inside experimental concrete ponds at an initial density of 100/m2. Commercial feed pellets were only offered to the fish. In treatments B and C, organic carbon was added at an estimated C/N ratio of 10 to stimulate biofloc growth as the food source for the prawn juveniles. There was no significant difference in catfish growth among treatments. Dissolved inorganic nitrogen concentrations in B and C were generally lower than in the control. Although significantly affected by the initial stocking density, prawn growth was comparable to that fed with formulated feed. Catfish co-culture with prawn with C organic addition resulted in significantly higher feed nitrogen utilization. Overall results suggest that catfish–prawn co-culture with C organic addition may improve total food conversion ratio, reduce nitrogen waste and generate additional income for catfish farmers.