Location: Warmwater Aquaculture Research Unit
2019 Annual Report
Objectives
1) Evaluate alternative feedstuffs and optimize feed formulations using traditional and alternative feedstuffs for cost-effective production of catfish, and determine if nutrient requirements differ for hybrid and channel catfish.
Sub-objective 1.1 Evaluate diets using alternative feedstuffs in low-protein diets for pond-raised hybrid catfish.
Sub-objective 1.2 Evaluate fortification of alternative diets with lysine and methionine to improve processing yield of channel catfish.
Sub-objective 1.3 Complete replacement of soybean meal using a combination of lower-cost protein sources for pond-raised hybrid catfish.
Sub-objective 1.4 Evaluate 32% or 36% protein, traditional or alternative feeds for fingerling hybrid catfish.
Sub-objective 1.5 Evaluation of growth and disease resistance of fish fed diets supplemented with taurine.
2) Develop more cost effective feeding and production strategies for hybrid and catfish production.
Sub-objective 2.1 Evaluate effects of maintenance feeding on growth and processing yield of market-size hybrid catfish.
Sub-objective 2.2 Compare hybrid fry production when feeding immediately at stocking with fry fed under an alternative feeding strategy of waiting six weeks before offering commercial diets.
3) Evaluate co-culture of alternative species for effects on water quality, biological control of disease vectors, and supplemental income for catfish producers.
Sub-objective 3.1 Co-culturing redear sunfish with channel catfish under commercial conditions.
Sub-objective 3.2 Extensive production of prawn Macrobrachium rosenbergii in fallow catfish production ponds for crop diversification.
Approach
Three 24% protein diets containing 30, 20, and 15% soybean meal will be compared with a 28% protein control diet. Hybrid catfish fingerlings will be stocked in ponds at 6,000 fish/acre. Each diet will be fed to five replicate ponds. All ponds will be harvested in October/November. A partial budget analysis based on feed and fish prices will be conducted to determine the economic benefit (if any) of using low-protein alternative diets versus the traditional control diet.
This study will evaluate five 28% protein diets fortified with varoious supplements. Experimental design, diet analyses, procedures for stocking, feeding, pond management, data collection and statistical and economic analysis will be the same as described for Sub-objective 1.A.
All soybean meal in hybrid catfish feeds will be replaced with various combinations of cottonseed meal, distiller’s grains with solubles, peanut meal, and porcine meat and bone meal. Pond will be stocked with hybrid catfish fingerlings, and diet analyses, experimental design, procedures for stocking, feeding, pond management, data collection and statistical analysis, and economic analysis will be the same as described for Sub-objective 1.A.
Four thousand small hybrid catfish fingerlings will be stocked into 20 tanks with 200 fish each. Four diets of 32% or 36% protein using either soybean meal or soybean substitutes will be evaluated. Diet, statistical, and economic analysis will be the same as described for Sub-objective 1A.
Growth and disease resistance of juvenile channel catfish will be evaluated in fish fed diets with varying levels of taurine in replicated aquaria.
The proposed study will evaluate effects of no feeding, maintenance feeding, and re-feeding on growth, feed conversion ratio, and processing yield of hybrid catfish. Market-size hybrid catfish (1.5 lb) will be stocked into ponds at the end of May or early June. The experimental design, procedures for stocking, feeding, pond management, data collection and statistical analysis will be the same as described for Sub-objective 1.A.
This study will compare production of hybrid fry fed immediately at stocking in 0.4 ha ponds with that of fry not fed until 6 weeks after stocking.
Four ponds will be stocked with channel catfish (600 fish/pond) and redear sunfish (10 fish/pond); four ponds will be stocked with redear sunfish only (10 fish/pond); four ponds will be stocked with catfish only (600 fish/pond). The study will be repeated yearly with the same stocking rates but with varying fish size. Catfish will be fed and managed according to standard industry practices and cultured through one production season.
Each treatment will consist of 4 replicate ponds to evaluate using hay, planted wheat, or rice as substrates to increase freshwater prawn production. Ponds with no substrate addition will served as controls. Ponds will be stocked with 10,000 prawn/ac. All ponds will be fed range cubes. Prawns will be harvested in the fall. All prawns will be counted and collectively weighed, and production will be compared among the treatments.
Progress Report
Research was conducted to examine growth efficiency of fingerling hybrid catfish fed diets containing varying levels of crude protein. Four diets were evaluated in experimental ponds containing 35% protein and 7.5% fish meal (standard commercial fingerling diet), all plant diets containing 32 and 28% protein and a 28% protein diet formulated with porcine meat bone and blood meal (PMBB). Fish with a mean initial weight of 2.9 g/fish were fed once daily to apparent satiation for 107 days. No significant differences were observed for total diet fed, gross yield, final weight, survival, or condition factor among dietary treatments. However, fish fed the 28 and 32% all-plant-protein diets had a slightly, but significantly higher feed conversion ratio than fish fed the 35% protein fish meal diet. There were no significant differences in chlorophyll a and nitrite concentrations in the pond water, but ponds receiving the 35% protein diet had significantly higher ammonia than those receiving 28% protein diets. Economic analysis suggested potential cost savings by using low-protein and all-plant-protein diets for hybrid catfish fingerling production. Data demonstrates hybrid catfish fingerlings can be efficiently raised on all-plant based lower protein diets. Information generated from this study is being used by commercial feed mills in least-cost feed formulations.
A second food fish production pond study evaluated the effects of varying levels (0, 10, 15, 20, and 25%) of porcine meat and bone meal (PMB) in diets on production and processing characteristics and body composition of pond-raised hybrid catfish. There were no significant differences in total feed fed, weight gain, or survival among dietary treatments, but fish fed diets containing 10% or more PMB had significantly greater net yield (live weight) and a lower feed conversion ratio than fish fed the control diet without PMB. Although no significant differences were detected for carcass yield and fillet yield among dietary treatments by analysis of variance, carcass yield (dressout yield) and fillet yield decreased and fillet fat levels increased linearly with increasing PMB levels. Results from the study demonstrate 10% PMB could be used in the diet for an entire growing season without marked impacts on growth, processing yield, or body composition of pond-raised hybrid catfish. Higher PMB levels up to 25% may be used for short-term feeding when its price is favorable compared with soybean meal. However, caution should be taken when using high PMB levels during the latter part of growth cycle because of the negative effects on processing yield and fillet fat levels. Information generated from this study is being used by commercial feed mills in least-cost feed formulations.
Research developed from the previous Specific Cooperative Agreement “Improving Production Strategies in Catfish Farming” led to nursery pond management practices promoting desirable zooplankton populations serving as a natural food source and sparing the use of prepared diets during the initial stages of production. While previous work demonstrated properly fertilized ponds can support channel catfish fry growth without the addition of supplemental fry feed (pulverized diet), the contribution of natural and supplemental feed to catfish fry growth is not known. Stable C and N isotope ratios were used to quantify the contribution of zooplankton and commercial diets to growth of channel catfish and hybrid catfish. Channel and hybrid catfish were stocked in fertilized 0.04 hectare (ha) experimental ponds at a rate of 10,000 fry/pond. Pulverized diets containing 35 protein were administered daily to each pond until fry were observed feeding on the prepared diets at the pond water surface. After one week fish were fed a pelleted floating diet sized to accommodate gape size. Fish were collected from ponds twice weekly using a 9-m minnow seine (3-mm mesh) for 4 weeks during June and July. Thereafter, fish were collected once weekly for an additional three weeks during late July and August. Fish, zooplankton, and feed samples (N=201) were dried for 24 h, ground into fine powders, packed for solid samples. Stable carbon (C) and nitrogen (N) isotope ratios of all samples were measured at the University of California at Davis Stable Isotope Facility. Channel and hybrid catfish fry had no differences in the timing and extent of zooplankton and feed use in ponds. Both fish types used zooplankton and feed equally to support growth (~50% from each source) from the time of pond stocking, and there were no differences in growth rates by length or weight.
Objective 3, “co-culture of alternative species for effects on water quality, biological control of disease vectors, and supplemental income for catfish producers” was removed from the project due to dynamic changes in industry practices and subsequent research priorities. As such, research focused on adoption and economics of alternative production practices which is a continuation of the previous specific cooperative agreement “Improving Production Strategies in Catfish Farming”. U.S. catfish farmers have been exploring alternate production technologies (intensive aeration, in-pond raceways, and split-pond systems) for several years. A multi-state (Arkansas, Alabama, Mississippi) survey identified split pond as the most rapidly adopted technology, with 1,600 acres in 2013, followed by intensively aerated ponds (1,200 acres). High yield, ease of adoption, and greater control over the production process associated with the alternate- production technologies were the major reasons for technology adoption. High investment costs and increased risk associated with these technologies were the main reasons for not adopting the new technologies. Technology adopters had significantly larger farms, greater numbers of ponds, and a significantly greater percentage used hybrid catfish.
Successful industry-wide adoption of newly developing technologies like split-pond systems and intensively aerated ponds were possible as they brought cost efficiencies. Two economic studies showed that these alternative production technologies were able to spread the higher fixed costs over greater volumes of production. Estimates of cost of production of hybrid catfish raised in split-ponds and intensively aerated systems showed long-term profitability. The cost of catfish production in these systems were sensitive to yield, fish prices, and feed prices and their variations contributed the most to downside risk. A fifth study provided an economic comparison of cost efficiencies in alternative technologies such as split-pond systems, intensively aerated ponds, and in-pond raceway systems under a uniform set of economic assumptions using a standard enterprise budget analysis. Cost of production of hybrid catfish raised in these systems was the highest in in-pond raceways and the lowest from split-ponds. Risk analysis showed stochastic dominance of intensively aerated ponds and split-pond systems over in-pond raceway systems.
A sixth study provided understanding of the best investment plan that allowed the transition an entire farm to alternative systems. The 6-year mixed-integer-recursive programming model developed included traditional ponds, re-working existing ponds to make them more productive, converting traditional ponds to split-ponds or adding additional aeration. The model selected primarily adoption of split-ponds as the profit-maximizing strategy under favorable market conditions and unlimited availability of investment capital. Higher feed prices and lower fish prices shifted the profit-maximization strategies from split-ponds to intensively aerated systems and traditional single-batch systems. Restricted availability of investment capital had a strong negative effect on those farms with greater percentages of older ponds that required re-working. Farmers that had reworked ponds more recently were able to invest the greater profits from the higher yields to transition more rapidly to new technologies. Larger farms could transition greater proportions of the farm to new technologies than could smaller farms.
Accomplishments
1. Reduction of animal protein in catfish production diets. Feed costs represent about one-half of the variable cost of production and in an environment of high grain and energy prices careful consideration to feed formulations is critical to maintaining farm profitability. Since animal protein is one of the most costly feed ingredients, relying in all-plant based diets would represent a considerable reduction in feed costs. Experimental pond studies demonstrated juvenile hybrid catfish could be fed all-plant based diets containing 28% protein without reducing total feed fed, final weight gain or survival. However, fish fed the 28 and 32% all-plant-protein diets had a slightly, but significantly higher feed conversion ratio than fish fed the 35% protein fish meal diet. The 35% protein fish meal control diet cost $676 per metric ton, while the 28% and 32% all-plant protein diets and the 28% protein PMBB diet cost $123, $96, and $112 per metric ton less, respectively. Economic analysis showed switching from a 35% protein traditional fingerling diet to alternative diets had an economic benefit, ranging from $1,865 to $2,405/hectare (ha) owing to the relatively lower feed ingredient prices. Similar results were demonstrated with food-fish production diets where total feed fed, weight gain and survival was similar among fish fed all plant based diets or diets containing porcine meat and bone meal (PMB). However, fish fed diets containing 10% or more PMB had significantly greater net yield and a lower feed conversion ratio than fish fed the control diet without PMB and carcass yield and fillet yield decreased and fillet fat levels increased linearly with increasing PMB levels. Data demonstrates catfish in all stages of production can be raised on less expensive all-plant based diets sparing the use of animal protein in animal production. Information generated from this study by ARS scientists in Stoneville, Mississippi, is being used by commercial feed mills in least-cost feed formulations.
2. Reduction in feed costs in fingerling production. Fingerling production begins in spring of the year as catfish fry (4-7 days of age post hatch) are transferred from the hatchery to nursery ponds. Based on research generated from the previous Specific Cooperative Agreement “Improving Production Strategies in Catfish Farming” pond fertilization programs were developed to promote optimal zooplankton communities to serve as a natural food source for newly stocked fry. Channel and hybrid catfish fry had no differences in the timing and extent of zooplankton and feed use in ponds. Both fish types used zooplankton and feed equally to support growth (~50% from each source) from the time of pond stocking, and there were no differences in growth rates by length or weight. The fish used feed to support growth before they were visually observed accepting the feed at the surface of ponds 4 weeks after stocking. Zooplankton are clearly important to support desirable growth of channel and hybrid catfish fry in ponds. Thus, by ARS scientists in Stoneville, Mississippi, recommend managers monitor densities of preferred zooplankton prey in ponds and use inorganic fertilization methods to enhance zooplankton production, as necessary. Although feed partially supported zooplankton production in this study, we caution against overfeeding, because this practice is expensive, inefficient, and risks hypoxia formation in ponds. Finding no differences in diets and growth rates between channel and hybrid catfish, we provisionally recommend managers practice similar pond management strategies for both fish types. Minimizing high protein fry diets during the initial stages of fingerling production can save producers around $500/hectar.
3. Production efficiency of technology adoption. Adoption of alternative catfish production technologies have resulted in achieving economic efficiencies in catfish industry, primarily due to the spreading of fixed costs over greater volumes of production. Current trends are indicative of increased adoption of intensively aerated ponds in catfish industry, primarily due to its relative ease of adoption compared to split ponds. Additionally, the market prices have gone down in recent years. With more favorable and stable market prices, split ponds are preferred over intensively aerated ponds, while reverse holds true when market prices are more unstable and volatile. Hence, market conditions as well as producers’ ability to bear risk determine future trends in adoption of alternative catfish production technologies. This information generated by ARS scientists in Stoneville, Mississippi, is being utilized by integrated and smaller catfish producers to develop information based cost effective production strategies reflecting anticipated market conditions.
Review Publications
Kumar, G. 2018. Aquaculture production and marketing: A peek into the world of producers and consumers. Agricultural Economics. 22(3):279-283.
Kumar, G., Engle, C., Hanson, T., Tucker, C.S., Brown, T., Bott, L., Roy, L., Torrans, E.L., Boyd, C., Recsetar, M., Park, J. 2018. Economics of alternative catfish production technologies. Journal of the World Aquaculture Society. 49:1039-1057.
Kumar, G., Engle, C., Tucker, C.S. 2018. Factors driving aquaculture technology adoption. Journal of the World Aquaculture Society. 49(3):447-476.
Kumar, G., Byars, T., Greenway, T., Khoo, L., Aarattuthodiyil, S., Griffin, M., Wise, D. 2019. Economic assessment of commercial-scale Edwardsiella ictaluri vaccine trials in U.S. catfish industry. Agricultural Economics. 23(2):1-22.
