Location: Warmwater Aquaculture Research Unit
2017 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
A pond nutrition study was conducted to evaluate effects of lysing and methionine fortification of alternative diets on processing yield of channel catfish. A traditional all-plant 28% protein control diet was compared to alternative diets with and without lysine and methionine supplementation. Lysine and methionine was added to the alternative diets equivalent to a 32% protein diet to determine the benefit of elevated protein levels related to each supplement. Channel catfish fingerlings (mean initial weight = 43 gram (g)/fish) were stocked into 25 ponds (0.04 hectare, ha) at a density of 14,826 fish/ha with five ponds per treatment. Fish were fed once daily to apparent satiation for a 173 day growing season. There were no significant differences in total diet fed, net yield, weight gain, and survival among dietary treatments. There were also no significant differences in carcass yield, fillet yield, and fillet proximate composition. Fish fed the traditional control diet had slightly, but significantly, lower feed conversion ratio than fish fed alternative diets, which is likely related to higher dietary fiber levels in the alternative diets. Results from this study show there is no benefit to fortification of lysine and methionine in alternative diets on processing yield of pond-raised channel catfish.
A second pond nutrition study was conducted to evaluate using combinations of two or three alternative protein sources to replace soybean meal in diets for channel catfish. Six 28% protein diets containing various combinations of alternative protein feedstuffs: cottonseed meal, corn distillers dried grains with solubles (DDGS), corn germ meal, peanut meal, and porcine meat and bone meal (PMBM) were evaluated. Channel catfish stockers (mean initial weight = 87 g/fish) were stocked into 30 earthen ponds (0.04 ha) at a density of 14,826 fish/ha with five ponds per dietary treatment. They were fed once daily to apparent satiation for a 183-day growing season. There were no significant differences in total diet fed, net yield, weight gain, survival, processing yield, and fillet proximate composition among dietary treatments. Results from this study show that all soybean meal could be replaced by two or three moderate- and high-protein alternative feedstuffs without significantly affecting growth performance, processing yield, and fillet proximate composition of pond-raised channel catfish during food fish grow out.
A third pond nutrition study was conducted to evaluate the replacement of soybean meal with combinations of two or three alternative protein feedstuffs in diets for pond-raised hybrid catfish. Alternative protein sources evaluated included cottonseed meal, DDGS, peanut meal, and PMBM. Hybrid catfish fingerlings with a mean initial weight of 35 g/fish were stocked into 25 earthen ponds (0.04 ha) at a density of 14,826 fish/ha. Fish were fed once daily to apparent satiation for 166 days. No significant differences were observed for total diet fed, net yield, weight gain, survival, carcass and fillet yield, or fillet proximate composition among dietary treatments. Results show all soybean meal may be replaced by combinations of cottonseed meal and one or two of other alternative protein sources including DDGS, peanut meal, and PMBM in the diet without markedly affecting production and processing characteristics and fillet proximate composition of pond-raised hybrid catfish.
Production variables between hybrid catfish (Ictalurus punctatus x I. furcatus) nursery ponds fed immediately after stocking (industry standard) versus delayed feeding after stocking were compared. Nine 0.04 ha ponds were fertilized and stocked with swim-up fry at 10,000/pond (250,000/ha). Ponds were randomly assigned to the standard feeding protocol or the delayed feeding protocol. At 2 week post-stocking, fish in the delayed feeding treatment were significantly smaller than fish in the standard feeding protocol. Therefore, all ponds began receiving commercial diets after 2 week (wk). At 2 week post-stocking and continuing through 5 week post-stocking, average individual fish length and weight was greater in the standard feeding protocol compared to the delayed feeding protocol. At harvest, there were no differences in production variables between the two feeding protocols. Unlike a previous study with channel catfish fry, where feed was withheld for 6 week without compromising production, noticeable deficiencies in hybrid fry growth were observed after only 2 weeks of feed restriction. Although compensatory growth was observed, and restricting feed did not result in differences in production variables observed 6 week post-stocking, delayed feeding of hybrid catfish is not recommended past 2 weeks. At the feeding rate and prices during this study, we observed feed savings of $38.75/ha by delaying feeding for 2 weeks.
Work is being conducted in support of research to identify risk factors and putative predictive indicators of a virulent strain of Aeromonas hydrophila (VAh) that is causing significant losses to the catfish industry. The epidemiology of this disease is being investigated to determine if environmental triggers, associated with toxic algal blooms and water quality perturbations, are associated with VAh outbreaks. Water samples have been collected monthly on farms experiencing VAh outbreaks, along with samples collected during the disease epizootic. Zooplankton and phytoplankton communities and water quality variables have been analyzed. This data, along with pathogen prevalence (fish and environment) and disease loss data has been sent to collaborators at Mississippi State University to characterize abiotic and biotic conditions associated with VAh outbreaks.
Accomplishments
1. Nutrition studies were conducted to reduce feed costs using alternative feed ingredients. Soybean meal has been the main protein source for pond-raised catfish because of its high quality protein and balanced essential amino acid profile. However, soybean meal prices have increased dramatically in recent years and have reached U.S. $600/metric ton at times. Recent research with channel catfish and hybrid catfish has generally shown up to 50% soybean meal could be replaced by cottonseed meal and one of the corn-milling by-products corn gluten feed or corn germ meal, in the diet without negatively affecting fish performance. Results from ponds studies by ARS scientists at Stoneville, Mississippi, with both channel catfish and hybrid catfish demonstrate it is possible to replace all soybean meal by two or three moderate- and high-protein alternative feedstuffs in the diet without significantly affecting growth performance, processing yield, and fillet proximate composition of the fish. These data provide flexibility in formulating cost-effective diets for pond-raised catfish. These alternative diets may be used to feed pond-raised catfish during food fish grow out especially during periods of high soybean meal prices.
2. Nursery pond management practices were evaluated in efforts to reduce feed costs by promoting optimal zooplankton populations to serve as a natural food source during the initial stages of fish development. Previous work from this project demonstrated natural pond biota could support optimal growth of channel catfish fry for 6 weeks without supplemental feed. However unlike channel catfish, noticeable deficiencies in hybrid catfish fry growth was observed by ARS scientists at Stoneville, Mississippi, after only 2 weeks. Although, compensatory growth was observed, and restricting feed did not result in differences in production variables observed 6 week (wk) post-stocking, delayed feeding of hybrid catfish is not recommended past 2 weeks. Data indicates hybrid catfish do not have to be fed fry diets for the first 2 weeks of development, provided the recommended fertilization schedule is followed to promote optimal pond productivity. At the feeding rate and prices during this study, we observed feed savings of $38.75/hacter by delaying feeding for 2 wks.
Review Publications
Menghe, L.H., Lucas, P.M., Bosworth, B.G. 2017. Evaluation of various combinations of alternative protein feedstuffs to replace soybean meal in diets for pond-raised channel catfish. North American Journal of Aquaculture. 79(2):163-167.
Mischke, C., Griffin, M., Li, M., Wise, D., Greenway, T. 2017. Postponed feeding does not substantially reduce production expense during pond rearing of hybrid catfish fry. North American Journal of Aquaculture. 79:135-139.
Li, M., Lucas, P. 2017. Evaluation of Peanut Meal as an Alternative Dietary Protein Source for Channel Catfish. North American Journal of Aquaculture. 79(1):95-99.
Li, M., Lucas, P. 2017. Effects of feeding frequency on apparent energy and nutrient digestibility/availability of channel catfish, Ictalurus punctatus, reared at optimal and suboptimal temperatures. Journal of the World Aquaculture Society. 48(1):132-136.
Mischke, C.C., Griffin, M.J., Wise, D.J., Greenway, T.E. 2016. Effects of co-stocking smallmouth buffalo, Ictiobus bubalus, with channel catfish, Ictalurus punctatus. Journal of the World Aquaculture Society. 47:212-219.
Li, M.H., Wise, D.J., Mischke, C.C., Lucas, P.M. 2016. Effects of dietary protein concentrations and sources on production characteristics of pond-raised hybrid catfish fingerlings. North American Journal of Aquaculture. 78:295-300.
