Evaluation of Mixed-Feeding Schedules with Varying Dietary Protein Content on the Growth Performance and Reduction of Cost of Production for Sutchi Catfish,Pangasius hypophthalmus (Sauvage) with Silver Carp,Hypophthalmichthys molitrix (Valenciennes)

Abstract

An on-station pond trial was conducted for 6 months to investigate the suitability of mixed-feeding schedules with varying protein levels on the growth of sutchi catfish, Pangasius hypophthalmuswith silver carp, Hypophthalmicthys molitrixwith a view to minimizing the cost of production. Five different feeding regimes employed were: high protein diet (30% protein, H), low protein (15% protein, L), one day low protein diet followed by one day high protein diet (1L/1H), 7 day low protein diet followed by 7 day high protein diet (7L/7H), and 14 day low protein diet followed by 14 day high protein diet (14L/14H). Ten experimental ponds each of 0.008 ha size were divided into 5 treatment groups each with two replicates. Fishes were stocked at the ratio of 80:20 (sutchi catfish:silver carp) at the total rate of 25,000/ha. Feeding rate was calculated only on the basis of sutchi catfish weight only and fish were fed at the rate of 15,10, 8, and 5% of their body weight for 1st, 2nd, 3rd months, and the rest of the experimental period, respectively. The ranges of water quality parameters during the study period were: temperature 22°C to 32.8°C, dissolved oxygen 4.30 to 7.44 mg/L, pH 6.85 to 7.50, and transparency 21.9 to 32.2 cm. The result of the study showed that significantly (P < 0.05) higher fish weight gain was achieved in feeding schedules of H and 1L/1H and lowest with 14L/14H. The feed conversion ratio (FCR) values ranged between 2.06 and 2.51 with H and 1L/1H showing significantly the best FCR. The FCR values were very low when weight of silver carp was considered which ranged between 1.58 and 1.68. The survival (%) of sutchi catfish were lower (78.1 to 82.5%) compared to that of silver carp (90–95%). The total production of sutchi catfish ranged between 3594 and 7095 kg/ha and silver carp ranged between 1777 and 2220 kg/ha. A simple economic analysis showed that fish in 1L/1H fed alternately with low and high protein diets resulted in the highest net profit. The result of the study suggest that for profitable sutchi catfish farming in Bangladesh, farmers can adopt a mixed-feeding schedule of alternated low and high protein diet instead of continuously feeding a high protein diet.     

Effects of Phosphate Type on the Quality of Vacuum-Tumbled Catfish Fillets

The objective of this study was to determine the effects of various agglomerated phosphate blends on the quality of vacuum-tumbled catfish fillets. Catfish fillets were tumbled with a brine solution at 15% over initial, raw weight prior to tray-packing and storage at 4°C for 10 days. Fillets were evaluated for protein exudate, tumbling yield, color, pH, cooking loss, tenderness, purge loss, and shelf life. A specific blend of agglomerated sodium phosphates (AGSP) that contains mono-, tri-, and polyphosphates had significantly less protein (p < 0.05) exudate and significantly higher pH (p < 0.05) than other treatments. All phosphate treatments significantly increased (p < 0.05) tenderness and significantly decreased (p < 0.05) purge loss, but agglomerated phosphate blends significantly decreased (p < 0.05) cooking loss and yellowness. Psychrotrophic plate counts for all phosphate treatments were similar to the control at each storage time. All phosphate treatments improved the yield and quality of catfish fillets, but the use of AGSP may optimize quality attributes.     

Postmortem Changes in Blast,Brine and Brine-Coil Frozen Albacore

This study investigated effects of bleeding or dressing, freezing at sea in refrigerated brine, coil refrigeration or air blast systems, and vacuum packaging on albacore quality. Analytical procedures at 0, 3, 6, 9, and 12 months determined aerobic plate counts, flesh pH, salt, dimethylamine nitrogen (DMA-N), thiobarbituric acid reactive substances, and nucleotides. Sensory evaluation at 9 months storage suggested that processing at sea many improve flesh appearance. No significant differences were evident in microbial or chemical indices between handling, freezing or packaging treatments. DMA-N increased only slightly during frozen storage.     

Digestibility of dietary components and amino acids in plant protein feed ingredients in striped catfish (Pangasianodon hypophthalmus) fingerlings

The apparent digestibility (AD) of dietary components, energy and essential amino acids (EAA) of selected locally available plant protein feed ingredients in striped catfish (Pangasianodon hypophthalmus) fingerlings was studied. The AD of the test ingredients (ADi) differed (P < 0.05) and ranged from 66.2 to 89.6% for ADi_DM, from 63.6 to 91.3% for ADi_CP, from 65.4 to 85.3% for ADi_OM and from 69.8 to 89.3% for ADi_GE. The highest ADi_DM, ADi_OM and ADi_GE in the test ingredients was obtained for broken rice, maize meal and soybean meal, while the lowest values were obtained for duckweed meal. Soybean meal and duckweed meal had the highest ADi_CP, while there were no differences (P > 0.05) between the other test ingredients. The AD of total and individual EAA was higher in soybean meal, duckweed meal and broken rice than in the other test feed ingredients (P < 0.05). The lowest AD of individual EAA was found in maize meal, followed by cassava leaf meal and sweet potato leaf meal (P < 0.05). The low AD of individual plant feed ingredients may limit their potential to be used as replacement for fish meal in the feed.     

Digestibility of dietary components and amino acids in animal and plant protein feed ingredients in striped catfish (Pangasianodon hypophthalmus) fingerlings

The apparent digestibility (AD) of dietary components, energy and essential amino acids (EAA) of selected locally available animal and plant protein feed ingredients in striped catfish (Pangasianodon hypophthalmus) fingerlings was studied. The AD of the test ingredients (ADi) differed (P < 0.05) and ranged from 81.1% to 90.8%, for ADi_DM, from 84.0% to 95.0% for ADi_CP, from 78.4% to 86.9% for ADi_OM and from 79.0% to 87.8% for ADi_GE. The highest ADi_DM, ADi_CP and ADi_OM in the test ingredients were found for shrimp head meal, catfish by‐product meal, golden apple snail and groundnut cake, while the lowest values were obtained for earthworm meal and rice bran. The highest ADi_GE was found in rice bran, followed by golden apple snail and catfish by‐product meal, while there were no differences (P < 0.05) between the other test ingredients, except for earthworm meal. The AD of total and individual EAA was high in catfish by‐product meal and shrimp head meal, followed by decreasing AD in golden apple snail, groundnut cake, rice bran and earthworm meal ingredients (P < 0.05). The low AD of earthworm meal may limit its potential to be used as replacement for fish meal in the feed.     

EFFICIENCY CHANGE AND TECHNOLOGICAL PROGRESS IN THE U.S. CATFISH-PROCESSING SECTOR, 1986 TO 2005

Productivity growth of the catfish-processing sector in the United States was measured over the time period of 1986 through 2005. The analysis evaluated the efficiency with which products are produced by catfish processing plants. The Malmquist index is employed to decompose the total factor productivity into growth associated with technical efficiency change and technological progress. The relationship between Farrell's measure of technical efficiency and the Shepard's distance function provides the theoretical foundation for estimating the Malmquist production index using data envelopment analysis. The results indicate that, between 1986 and 2005, there was no technical progress or adoption of new techniques with significant impact on catfish processing. Technical efficiency change, which is associated with input use efficiency, varied with type of fish size processed. It decreased from 1985 to 1995 as the industry struggled to establish the most efficient fish size to process. Between 1995 and 2005 the fluctuation continued but at a higher mean. Productivity growth and long-term competitiveness are likely to result from adoption of new processing innovations by the catfish-processing sector.     

OPTIMAL SIZE OF FINGERLING TO UNDERSTOCK IN CATFISH GROW-OUT PONDS: AN APPLICATION OF A MULTI-PERIOD INTEGER PROGRAMMING MODEL

This article developed a multi-period linear programming model to identify the optimal size of fingerling to understock to maximize multi-period returns on a catfish grow-out farm. Grow-out production alternatives included understocking three different sizes (7.6 cm, 12.7 cm, and 17.8 cm) of fingerlings in multiple-batch production at 15,000 fingerlings per hectare. Fingerlings were produced either with or without thinning at different stocking densities. Results showed that the optimal size of fingerling to understock was 12.7 cm. On-farm production of fingerlings was optimal across all farm sizes but the fingerling production technique selected varied with farm size. Models of larger farm sizes indicated that it is optimal to thin fingerlings, while for smaller farm sizes, producing fingerlings without thinning was optimal. When farm size was treated as an endogenous variable in the farmer's profit-maximizing decisions, the optimal size of a catfish farm was 404 water-ha. Sensitivity analyses suggested that net returns were sensitive to changes in the key parameters of the model (such as interest rates, feed conversion ratios, survival rates, catfish prices, harvesting costs, and the availability of operating capital), whereas the optimal size of fingerlings to understock was robust to variations in the model's parameters.     

PRODUCTIVE EFFICIENCY OF CATFISH FARMS IN CHICOT COUNTY,ARKANSAS

Technical, allocative, and cost efficiency measures of a sample of small-and medium-sized catfish farms in Chicot County, Arkansas were estimated using a weight-restricted data envelopment analysis technique. A measure of cost efficiency is used to determine operator characteristics, farm practices, and institutional support services that are likely to lead to higher levels of efficiency. Experience of the operators and extension contacts were important factors positively influencing farm level efficiency. Extension services in Chicot County generated about $5.2 million in cost savings among catfish farms or about $2,737 per contact. Importantly, higher cost efficiency of catfish farm efficiency in Chicot County, Arkansas, can be achieved by adjusting inputs used in production to optimal levels rather than by adjusting the scale of operation.     

ARKANSAS CATFISH FARMERS AND MARKETING CONTRACTS: SOME INSIGHTS INTO MOTIVATIONS

Interest in sales contracts in the catfish industry increased in the late 1990s and early 2000s as a result of increased import pressures and lower product prices. The study uses survey data fitted to a probit model to examine the motivations for contracting sales, and whether farm size is an important determinant of sales contracts usage. The article concludes that Arkansas catfish farmers with large acreages and therefore large volumes of production have a high probability of utilizing contracts to handle their sales but not necessarily with privately-owned independent processors. The farmers are not motivated to engage in sales contracts by reduction in income or price risks. They are motivated by production and management issues, which appear consistent with reductions in transactions costs relating to asset specificity and quality measurement as the reason for contracting.     

PERCEPTIONS OF RISK AND RISK MANAGEMENT IN VIETNAMESE CATFISH FARMING: AN EMPIRICAL STUDY

Although Vietnamese catfish farming has grown at a rapid rate in recent years, the industry has also faced many problems that affect its sustainability. This paper explores the perceptions of catfish farmers regarding risk and risk management strategies in their production activities. The relationships between farm and farmer socioeconomic characteristics and perceptions of risk and risk management are also examined. Data for the study were collected in 2008 from a sample of 261 catfish farmers in the Mekong Delta, Vietnam using a questionnaire survey. The results show that, in general, price and production risks were perceived as the most significant risks. Farm management and technical measures were perceived to be more effective than other kinds of risk management strategies in risk reduction. Although price risks were rated as important, price risk management strategies were not perceived as important measures for risk mitigation. The results of the study are discussed to identify the implications for various industry stakeholders, including policymakers, processors, advisors, and developers of new risk management strategies.