Replacing Soybean Meal with Alternative Protein Sources in Diets for Pond‐raised Hybrid Catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus

The present study investigated the replacement of soybean meal with combinations of two or three alternative protein sources in diets for pond‐raised hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus. Alternative protein sources evaluated included cottonseed meal, distillers dried grains with solubles (DDGS), peanut meal, and porcine meat and bone meal (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 d. No significant differences were observed for total diet fed, net yield, weight gain, survival, carcass yield, fillet yield, or fillet proximate composition among dietary treatments. Results show soybean meal may be completely replaced by combinations of cottonseed meal and one or two 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. These alternative diets may be used during foodfish production when prices are favorable.     

Use of Corn Germ Meal in Diets for Pond‐Raised Channel Catfish,Ictalurus punctatus

Corn germ meal (CGM) is a by‐product of corn milling. On the basis of its nutrient composition and digestibility values, it appears to be a suitable ingredient for use in channel catfish, Ictalurus punctatus, diets. A study was conducted to examine the use of various levels of CGM in diets for pond‐raised channel catfish. Four 28% protein diets containing 0, 15, 25, and 35% CGM were evaluated. Fingerling channel catfish (mean initial weight: 71 g/fish) were stocked into 24, 0.04‐ha ponds at a rate of 14,826 fish/ha. Fish were fed once daily to apparent satiation for a 167‐d growing season. No significant differences were observed in total amount of diet fed, diet consumption per fish, net yield, weight gain, feed conversion ratio, survival, fillet yield, and fillet protein, fat, and moisture concentrations among fish fed diets containing various levels of CGM. Carcass yield decreased linearly as dietary CGM levels increased. Depending on prices, CGM can be used interchangeably with corn gluten feed in channel catfish diets as replacements for corn, wheat middlings, and soybean meal to reduce feed cost.     

Evaluation of Corn Gluten Feed and Cottonseed Meal as Partial Replacements for Soybean Meal and Corn in Diets for Pond‐raised Hybrid Catfish,Ictalurus punctatus×I. furcatus

This study examined the use of corn gluten feed (CGF) and cottonseed meal (CSM) to partially replace soybean meal and corn in diets for pond‐raised hybrid catfish, Ictalurus punctatus×I. furcatus. Five 28% protein diets containing various combinations of CGF and CSM were evaluated. Fingerling hybrid catfish (mean initial weight: 45 g/fish) were stocked into 25, 0.04‐ha ponds at a rate of 14,826 fish/ha. Fish were fed once daily to apparent satiation for a 179‐d growing season. CGF at 30% of the diet (10% CSM) and a combination of CGF and CSM up to 25% each did not affect physical quality (percentages floatability and feed dust) of the diet. No significant differences were observed in total amount of diet fed, net yield, diet consumption, weight gain, feed conversion ratio (FCR), survival, and fillet proximate nutrient composition among fish fed various diets. Results show that hybrid catfish can utilize CGF at levels up to 30% of the diet (10% CSM), and a combination of CGF and CSM up to 25% each without significantly affecting growth, diet consumption, FCR, and fillet proximate nutrient composition. However, a combination of CGF and CSM at 20% each and above reduced carcass yield.     

Efficacy of Crystalline Lysine in Alternative Diets for Pond‐raised Hybrid Catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus

A study was conducted to examine the efficacy of crystalline lysine in alternative diets for pond‐raised hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus. Two 28% protein alternative diets supplemented with l ‐lysine HCl at the required level based on 62% (previously published value) or 100% lysine availability were compared with a traditional 28% protein control diet. Hybrid catfish fingerlings (mean initial weight = 43 g/fish) were stocked into 15 earthen ponds (0.04 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‐d 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 and fillet lysine concentration among treatments. 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 that crystalline lysine can be considered 100% available when used to supplement lysine‐deficient diets for pond‐raised hybrid catfish.     

Response of Pond‐raised Fingerling Hybrid Catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus,to Dietary Protein Concentrations and Sources

This study examined four experimental diets with different protein concentrations and sources for pond‐raised fingerling hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus. A 35% protein diet with fishmeal was used as the control diet. Test diets were 32 and 28% all‐plant‐protein diets and a 28% protein diet with porcine meat, bone, and blood meal. Small fingerlings with a mean initial weight of 2.9 g/fish were stocked into 20 earthen ponds (0.04 ha) at a density of 172,970 fish/ha. They were fed once daily to apparent satiation for 107 d. 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 significantly higher feed conversion ratio than fish fed the 35% protein diet with fishmeal. 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.     

Effect of Dietary Protein Concentration on Growth and Processing Yield of Channel Catfish Ictalurus punctatus1

Abstract.— This study was conducted to evaluate the effect of dietary protein concentration and an all‐plant diet on growth and processing yield of pond‐raised channel catfish Ictalurus punctatus. Four diets were formulated using plant and animal proteins to contain 24%n, 28%, 32%, or 36% crude protein with digestible energy to protein (DE/P) ratios of 11.7, 10.2, 9.0, and 8.1 kcal/g, respectively. An all‐plant diet containing 28% protein with a DE/P ratio of 10.2 kcal/g was also included. Channel catfish fingerlings averaging 40 g/fish were stocked into 24, 0.04‐ha ponds at a density of 18,530 fish/ha. Five ponds were used for each dietary treatment except for the all‐plant diet which had four replicates. The fish were fed once daily to apparent satiation for 160 d. No differences were observed in feed consumption, weight gain, survival, carcass and nugget yield, or fillet moisture and protein concentrations among treatments. Fish fed the 28% protein diet had a lower feed conversion ratio (FCR) than fish fed diets containing 24% and 32% protein, but had a FCR similar to fish fed the 36% protein diet. Fillet yield was higher for fish fed the 36% protein diet than fish fed the 24% protein diet. Visceral fat was lower in fish fed the 36% protein diet than fish fed other diets. Fish fed the 32% and 36% protein diets exhibited a lower level of fillet fat than fish fed the 24% protein diet. The 36% protein diet resulted in a lower level of fillet fat than fish fed the 28% protein diet. There was a positive linear regression in fillet yield and fillet moisture concentration and a negative linear regression in visceral fat and fillet fat against dietary protein concentration. No differences in any variables were noted between the 28% protein diets with and without animal protein except that fish fed the 28% protein diet without animal protein had a higher FCR than fish fed the 28% protein diet with animal protein. This observation did not appear to be diet related since FCR of fish fed the 32% protein diet containing animal protein was not different from that of fish fed the 28% all‐plant protein diet. Data from the present study indicate that dietary protein concentrations ranging from 24% to 36% provided for similar feed consumption, growth, feed efficiency, and carcass yield. However, since there is a general increase in fattiness and a decrease in fillet yield as the dietary protein concentration decreases or DEP ratio increases, it is suggested that a minimum of 28% dietary protein with a maximum DEIP ratio of 10 kcal/g protein is optimal for channel catfish growout.     

Comparison of Channel Catfish,Ictalurus punctatus,and Blue Catfish,Ictalurus furcatus,Fed Diets Containing Various Levels of Protein in Production Ponds

A comparative study was conducted on growth and protein requirements of channel catfish, Ictalurus punctatus, and blue catfish, Ictalurus furcatus. Four diets containing 24, 28, 32, or 36% protein were fed to both channel (initial weight 6.9 g/fish) and blue (6.6 g/fish) catfish for two growing seasons. There were significant interactions between dietary protein and fish species for weight gain and feed conversion ratio (FCR). No significant differences were observed in weight gain of channel catfish fed various protein diets, whereas higher protein diets (32 and 36%) resulted in better weight gain in blue catfish than lower protein diets (24 and 28%). No consistent differences were observed in the FCR of channel catfish fed various levels of dietary protein, whereas significantly higher FCRs were noted in blue catfish fed the 24 and 28% protein diets compared with fish fed 32 and 36% protein diets. Regardless of dietary protein levels, blue catfish had higher carcass, nugget, and total meat yield, and higher fillet moisture and protein, but lower fillet yield and fillet fat. Regardless of fish species, fish fed the 36% protein diet had higher carcass, fillet, and total meat yield than fish fed the 28 and 32% protein diets, which in turn had higher yields than fish fed the 24% protein diet. It appears that blue catfish can be successfully cultured by feeding a 32% protein diet.     

Effect of Dietary Protein Concentration and Feeding Rate on Weight Gain,Feed Efficiency,and Body Composition of Pond-Raised Channel Catfish Ictalurus punctatus1

Two experiments were conducted in earthen ponds to evaluate the effect of dietary protein concentration and feeding rate on weight gain, feed efficiency, and body composition of channel catfish. In Experiment 1, two dietary protein concentrations (28% or 32%) and four feeding rates (≤ 90. ≤ 112, ≤ 135 kg/ha per d, or satiation) were used in a factorial arrangement. Channel catfish Ictalurus punctatus fingerlings (average size: 27 g/fish) were stocked into 0.04-ha ponds at a rate of 24,700 fish/ha. Fish were fed once daily at the predetermined maximum feeding rates for 282 d (two growing seasons). In Experiment 2, three dietary protein concentrations (24, 28, or 32%) and two feeding rates (≤ 135 kg/ha per d or satiation) were used. Channel catfish (average size: 373 g/fish) were stocked into 0.04-ha ponds at a rate of 17,300 fish/ha. Fish were fed once daily for 155 d. In both experiments, five ponds were used for each dietary treatment. Results from Experiment 1 showed no differences in total feed fed, feed consumption per fish, weight gain, feed conversion ratio (FCR), or survival between fish fed diets containing 28% and 32% protein diets. As maximum feeding rate increased, total feed fed, feed consumption per fish, and weight gain increased. There were no differences in total feed fed, feed consumption per fish, or weight gain between fish fed at ≤ 135 kg/ha per d and those fed to satiation. Fish fed the 28% protein diet had a lower percentage carcass dressout and higher percentage visceral fat than fish fed the 32% protein diet. Dietary protein concentrations of 28% or 32% had no effect on fillet protein, fat, moisture, and ash. Feeding rate did not affect FCR, survival, percentage carcass dressout, or fillet composition, except fillet fat. As feeding rate increased, percentage visceral fat increased. Fish fed at ≤ 90 kg/ha per d had a lower percentage fillet fat than fish fed at higher feeding rates. In Experiment 2, dietary protein concentration or maximum feeding rate did not affect total feed fed, feed consumption per fish, weight gain, FCR, or survival of channel catfish. Feeding rate had no effect on percentage carcass dressout and visceral fat, or fillet composition. This was due to the similar feed consumption by the fish fed at the two feeding rates. Fish fed the 24% protein diet had lower carcass dressout, higher visceral fat and fillet fat than those fed the 28% or 32% protein diet. Results from the present study indicate that both 28% and 32% protein diets provide satisfactory fish production, dressed yield, and body composition characteristics for pond-raised channel catfish fed a maximum rate of 90 kg/ha per d or ahove.     

Effects of varying dietary compositions using common feed ingredients on growth and feed efficiency of pond‐raised channel catfish Ictalurus punctatus (Rafinesque)

Two experiments were conducted to evaluate various ingredient combinations in a 28% or 32% protein diet for optimum performance of channel catfish Ictalurus punctatus. All diets contained soybean meal and corn, but with or without cottonseed meal, wheat middlings or fish meal (FM). Channel catfish fingerlings were stocked into 0.04 ha earthen ponds at 18 530 fish ha^?1. Fish were fed one of eight diets once daily to apparent satiation for two growing seasons. Results demonstrated that the dietary ingredient composition used had significant effects on fish performance, but magnitude of differences was relatively small. Overall, diets containing FM resulted in greater weight gain (Experiments 1 and 2) and lower feed conversion ratio (Experiment 1) than fish fed all‐plant diets. However, certain combinations of plant ingredients provided the similar fish growth as some diets containing FM. There were no significant differences in weight gain between fish fed soybean meal–corn or soybean meal–corn–wheat middlings‐based diets with cottonseed meal or FM. The use of wheat middlings in the diet had no significant effects on fish production characteristics.     

Low-Quality Diets for Growout of Channel Catfish,Ictalurus punctatus

Abstract

A feeding trial was conducted to evaluate low-quality diets for growout of pond-raised channel catfish. Five practical diets containing various levels of protein (10-28%) of varying quality (with or without animal protein and/or soybean meal), and with or without certain nutrient supplements (vitamin, minerals, lysine, or fat) were fed to channel catfish, Ictalurus punctatusstocked in 0.04-ha earthen ponds at a rate of 17,290 fish/ha. The diets were as follows: (1) 28% protein, nutritionally complete control; (2) 28% protein without supplemental vitamins, minerals, or fat; (3) 18% protein + supplemental lysine, vitamins, and minerals, but without animal protein; (4) 10% protein without animal protein, soybean meal, or supplemental vitamins and minerals; and (5) 10% protein + supplemental lysine, vitamins, and minerals, but without animal protein or soybean meal. Each diet was fed once daily to apparent satiation to fish in five replicate ponds for a single growing season. Fish fed diets containing 18% or 28% protein without supplements had similar diet consumption rates and weight gain as those fed the 28% control diet, but the fish fed the control diet converted diet more efficiently. Fish fed the 10% protein diet without supplements consumed less diet, converted diet less efficiently, and gained less weight than fish fed diets containing higher levels of protein. The addition of supplements to the 10% protein diet increased weight gain and processing yield as compared to fish fed the 10% protein diet without supplements. Body fattiness increased, fillet protein decreased, and carcass, fillet and nugget yields decreased as dietary protein decreased. The data show that pond-raised channel catfish can be grown effectively on a diet containing 18% protein that is of relatively low quality, but fattiness is increased and processing yield is decreased. However, because of the negative aspects of this diet, we would not recommend it for general use in commercial catfish culture. It could be used where fattiness and processing yield are not of consequence, such as recreational ponds. For that matter, the 10% diet without supplements could be used as well in these situations if maximum growth is not desired.     

Performance of Alternative Diets Containing Solvent‐Extracted Distillers Dried Grains with Solubles Compared to Traditional Diets for Pond‐Raised Channel Catfish,Ictalurus punctatus,and Hybrid Catfish,Ictalurus punctatus × Ictalurus furcatus

Two concurrent pond studies were initiated in April 2011 to evaluate feeds containing solvent‐extracted distillers dried grains with solubles (SE‐DDGS) in both 28 and 32% protein catfish feeds. Channel catfish, Ictalurus punctatus, were stocked in multiple‐batch production ponds at the University of Arkansas at Pine Bluff (UAPB) and hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus, in single‐batch production ponds at the National Warmwater Aquaculture Center (NWAC), Mississippi State University, Stoneville, Mississippi, USA. The experimental design was a 2 × 2 factorial with two protein levels (32 and 28% protein), with and without 20% SE‐DDGS. Fish were fed once daily to apparent satiation, and managed similarly to a commercial farm for 186 d at UAPB and 172 d at NWAC. For channel catfish, two‐way ANOVA showed significant effects of both protein level (28% being better than 32%) and protein source (20% SE‐DDGS diets being better than traditional diets) on yield, survival, total diet fed, and feed conversion ratio (FCR), due primarily to effects on the understocked fingerlings. Partial budget analysis suggested that the 28% protein diet with the 20% SE‐DDGS was preferred economically for the prevailing feed costs. For hybrid catfish, two‐way ANOVA did not show significant differences in total diet fed, yield, survival, and processing yields, but use of SE‐DDGS resulted in a lower FCR. Results showed that both channel and hybrid catfish can utilize 20% SE‐DDGS in the diet without adversely affecting production or processing characteristics.     

Low Protein Diets for Channel Catfish Ictalurus punctatus Raised in Earthen Ponds at High Density1

This study was conducted to evaluate the use of low protein diets for channel catfish Ictalurus punctatus raised in earthen ponds at high density. Fingerling channel catfish were stocked into 0.04-ha earthen ponds at a rate 24,700 fish/ha and fed experimental diets daily to satiation from April to October 1995. The five diets contained either 32, 28, 24, 20, or 16% crude protein with digestible energy to protein (DE:P) ratios ranging from 8.9 to 16.2 kcal/ g protein. Weight gain was not different among channel catfish fed diets containing 32, 28, or 24% crude protein. Fish fed diets containing 20% or 16% crude protein gained less weight than fish fed the diets containing 28% or 24% crude protein, but not statistically less than the fish fed the 32% crude protein diet. Feed consumption data followed similar trends as weight gain data. Feed conversion ratio increased linearly as dietary protein decreased, but was not significantly different (multiple range test) for fish fed diets containing either 32% or 28% crude protein. There were no differences in survival and hematocrit of fish fed the different diets. No differences (multiple range test) were observed in dressout percentages for fish fed the various diets, but dressout percentage tended to decrease linearly as dietary protein decreased. Visceral fat and fillet fat increased and fillet protein and moisture decreased linearly as dietary protein decreased. Results from this study indicated that dietary protein concentrations as low as 24% are adequate for maximum weight gain of pond-raised channel catfish fed daily to satiation. Fish fed dietary protein levels below 24% grew relatively well, particularly considering that dietary protein was reduced 40–50% below that typically used in commercial channel catfish feeds. However, dietary protein levels below 24% may increase fattiness to an unacceptable level presumably because of the high digestible energy to protein ratio.     

Comparison of Practical Diets with and without Animal Protein at Various Concentrations of Dietary Protein on Performance of Channel Catfish Ictalurus punctatus Raised in Earthen Ponds1

Abstract— A 2 × 5 factorial experiment was conducted using practical-type extruded feeds containing 20, 24, 28, 32, or 36% crude protein with or without animal protein. The animal protein supplement consisted of 4% menhaden fish meal and 4% meat, bone and blood meal. Channel catfish fingerlings (average size: 26.3 g/fish) were stocked into 50 0.04-ha ponds at a rate of 24,700 fishha. Five ponds were used for each dietary treatment. Fish were fed once daily to satiation for 202 d. There were no differences in feed conversion ratio (FCR), percentage fillet moisture, and survival among treatments. In fish fed diets containing no animal protein, feed consumption, weight gain, and percentage dressout were lower for fish fed the 20% protein diet than those fed diets containing 28% and 32% protein. Fish fed 28, 32, or 36% protein diets without animal protein did not differ in respect to percentage dressout and percentage visceral fat; fish fed the 36% protein diet had higher percentage fillet protein and a lower percentage fillet fat than fish fed other diets with the exception of fish fed the 28% protein diet. In fish fed diets containing animal protein, feed consumption, weight gain, percentage fillet protein and ash, and percentage dressout were lower and visceral fat was higher for fish fed the 20% protein diet than those fed other diets. Fish fed diets containing 24% protein and above with animal protein were not different in respect to weight gain and feed consumption, but fish fed the 24% protein diet had a higher percentage fillet fat than fish fed a 32% or 36% protein diet. Fish fed the 32% protein diet had a lower visceral fat. Considering animal protein vs non-animal protein with the data pooled across all diets without regard to dietary protein level, weight gain and FCR of fish fed diets containing animal protein were higher than those fed diets containing no animal protein. However, weight gain of fish fed diets containing 20, 28, or 32% protein with or without animal protein did not differ. Dressout percentage and fillet protein were higher and fillet fat was lower for fish fed diets containing no animal protein than those fed diets containing animal protein. Data from this study indicated that animal protein may not be a necessary dietary ingredient for fish fed 28% or 32% protein diets typically used for grow out of pond-raised channel catfish under satiation feeding conditions. Whether animal protein should be included in catfish diets containing less than 28% protein is unclear, since fish fed the 24% protein diet benefited from animal protein but those fed the 20% protein diet did not benefit from animal protein. Additional studies to provide more information on low-protein, all-plant diets are currently being conducted.     

Effects of available lysine concentrations in 28 and 32% protein diets on growth,feed efficiency,processing yield,and fillet composition of pond-raised channel catfish,Ictalurus punctatus

A study was conducted in earthen ponds to investigate the effects of available lysine (AL) concentrations in 28 and 32% protein diets on production and processing characteristics, proximate composition, and lysine concentrations in the fillet of channel catfish, Ictalurus punctatus. Diets were formulated to contain 28% protein with 1.22 and 1.43% AL, and 32% protein with 1.43 and 1.63% AL, which were equivalent to 4.37, 5.1, 4.46, and 5.1% AL of protein, respectively. Fingerlings with a mean initial weight of 32 g/fish were stocked into 20 ponds (0.04 ha) at 19,760 fish/ha. Fish were fed once daily to apparent satiation for 181 days. No significant differences were observed for total diet fed, net yield, weight gain, survival, or fillet proximate composition among dietary treatments. However, the 28% protein with low AL diet (1.22% AL of diet or 4.37% AL of protein) resulted in significantly lower carcass and fillet yield and fillet lysine level compared with fish fed the 28% protein diet with 1.43% AL (5.1% AL of protein) and 32% protein diets with 1.43 and 1.63% AL (4.47 and 5.1% AL of protein). Results suggest 1.43% AL of diet is adequate for both 28 and 32% protein diets for optimum growth, processing yield, and lysine retention in fillets for pond-raised channel catfish.     

Effect of Dietary Protein Concentration and Stocking Density on Production Characteristics of Pond-Raised Channel Catfish Ictalurus punctatus

Diets containing 28% and 32% crude protein were compared for pond‐raised channel catfish Ictalurus punctatus stocked at densities of 14,820, 29,640, or 44,460 fish/ha. Fingerling channel catfish with average initial weight of 48.5 g/fish were stocked into 30 0.04‐ha ponds. Five ponds were randomly allotted for each dietary protein ± stocking density combination. Fish were fed once daily to satiation for two growing seasons. There were no interactions between dietary protein concentration and stocking density for any variables. Dietary protein concentrations (28% or 32%) did not affect net production, feed consumption and weight gain per fish, feed conversion ratio, survival, processing yields, fillet moisture, protein and ash concentrations, or pond water ammonia and nitrite concentrations. Fish fed the 32% protein diet had slightly but significantly lower levels of visceral and fillet fat than fish fed the 28% protein diet. As stocking density increased, net production increased, while weight gain of individual fish, feed efficiency, and survival decreased. Stocking densities did not affect processing yield and fillet composition of the fish. Although highly variable among different ponds and weekly measurements, ponds stocked at the highest density exhibited higher average levels of total ammonia‐nitrogen (TAN) and nitrite‐nitrogen (NO₂‐N) than ponds stocked at lower densities. However, stocking density had no significant effect on un‐ionized ammonia‐nitrogen (NH₃‐N) concentrations, calculated based on water temperature, pH, and TAN. By comparing to the reported critical concentration, a threshold below which is considered not harmful to the fish, these potentially toxic nitrogenous compounds in the pond water were generally in the range acceptable for channel catfish. It appears that a 28% protein diet can provide equivalent net production, feed efficiency, and processing yields as a 32% protein diet for channel catfish raised in ponds from advanced fingerlings to marketable size at densities varying from 14,820 to 44,460 fish/ha under single‐batch cropping systems. Optimum dietary protein concentration for pond‐raised channel catfish does not appear to be affected by stocking density.     

Effects of Dietary Protein Concentration and Feeding Regimen on Channel Catfish, Ictalurus punctatus, Production

A factorial experiment was conducted to examine effects of dietary protein concentration (24, 28, 32, or 36%) and feeding regimen (feeding once daily or every other day [EOD]) on channel catfish, Ictalurus punctatus, production in earthen ponds. Compared with fish fed daily, fish fed EOD had lower feed consumption, weight gain, net production, and percentage of market‐size fish but had high feed efficiency and required fewer hours of aeration. Fish fed EOD also had lower carcass yield, fillet yield, and visceral and fillet fat. There was a significant interaction between dietary protein and feeding regimen for weight gain. No significant differences were observed in weight gain of fish fed daily with diets containing various levels of protein, whereas weight gain of fish fed EOD with a 24% protein diet was lower than those fed EOD with higher protein diets. Results suggest that response of channel catfish to dietary protein levels depends on whether the fish were fed daily or EOD. Feeding EOD to satiation improved feed efficiency and required less aeration compared with fish fed daily but also reduced net production and processing yield; therefore, EOD feeding should be examined closely before implementation.     

Effect of Dietary Protein Concentration on Growth and Processing Yield of Channel Catfish,Ictalurus punctatus Raised from Advanced Fingerlings to Large Marketable Size

Abstract

This study evaluated the effects of dietary protein concentration (26, 28, and 32%) and an all-plant protein diet (28% protein) on growth, feed efficiency, processing yield, and body composition of channel catfish, Ictalurus punctatus raised from advanced fingerlings to large marketable size (about 800 to 900 g/fish) for two growing seasons. Fingerling channel catfish (average weight = 56 g/fish) were stocked into twenty 0.04-ha ponds at a density of 18,525 fish/ha. Fish were fed once daily to satiation during the two growing seasons and fed according to recommended winter feeding schedules during the winter. There were no differences in diet consumption, weight gain, feed conversion ratio, survival, processing yields (carcass, shank fillet, and nugget), or fillet composition (moisture, protein, fat, and ash) among fish fed the various diets. These results indicate that a 26% protein diet containing plant and animal proteins or a 28% all-plant protein diet is adequate for channel catfish raised in ponds from advanced fingerlings to large marketable size without adversely affecting weight gain, feed efficiency, processing yield, or body composition. Large marketable-size channel catfish appear to use diets less efficiently but give higher processing yields compared to small marketable-size fish.     

Growth, feed conversion, fillet proximate composition and resistance to Edwardsiella ictaluri of channel catfish, Ictalurus punctatus (Rafinesque), blue catfish, Ictalurus furcatus (Lesueur), and their reciprocal F1 hybrids fed 25% and 45% protein diets

Juvenile channel catfish, Ictalurus punctatus (Rafinesque), blue catfish, I. furcatus (Lesueur), and their reciprocal Fl hybrids were fed practical diets containing 25% and 45% protein during a 10-week trial to determine the effects of genotype, dietary protein level and genotype X diet interactions on growth, feed conversion ratio (FCR), fillet proximate composition and resistance to the bacterium Edwardsiella ictaluri. Rankings of genotypes (best to worst) for absolute weight gain, percentage weight gain and FCR were: channel, channel female X blue male, blue, and blue female X channel male for the 25% protein diet; and channel, channel X blue, blue X channel, and blue for the 45% diet. Diet did not affect growth or FCR of channel catfish, but growth and FCR were better for blue catfish and both hybrids fed the 25% diet compared to those fed the 45% diet. Channel catfish additive genetic and maternal effects were favourable, and heterosis was negative for growth and FCR. After adjusting for effects of fish size, genotype had no effect on fillet composition. Fillet protein was higher for all genotypes, and fillet lipid was lower for blue catfish and hybrids fed the 45% diet than for fish fed the 25% diet. Genotype X diet interactions observed for growth, FCR and fillet lipid appeared to be a result of poor palatability of the 45% diet to blue catfish and hybrids. Survival (76-93%) and antibody levels (0.10-0.24 OD) after exposure to E. ictaluri at the end of the feeding trial were not affected by genotype or diet. Hybridization of blue catfish and channel catfish would not be an effective method for improving the traits measured for the fish strains and diets used in this study.     

Effects of Dietary Protein and Feeding Rate on Channel Catfish Ictalurus punctatus Production, Composition of Gain, Processing Yield, and Water Quality

A 2 ± 4 factorial experiment was conducted to examine effects of dietary protein level (28, 32, 36, and 40%) and feeding rate (satiation or ± 90 kg/ha per d) on production characteristics, processing yield, body composition, and water quality for pond-raised channel catfish Ictalurus punctatus. Fingerling channel catfish with a mean weight of 64 g/fish were stocked into 40 0.04-ha ponds at a rate of 17,290 fish/ha. Fish were fed once daily to apparent satiation or at a rate of ± 90 kg/ha per d for 134 d during the growing season. Dietary protein concentration had no effect on feed consumption, weight gain, feed conversion, survival, aeration time, or on fillet moisture, protein, and fat levels. Fish fed to satiation consumed more feed, gained more weight, had a higher feed conversion, and required more aeration time than fish fed a restricted ration. Visceral fat decreased, and fillet yield increased as dietary protein concentration increased to 36%. Carcass yield was lower for fish fed a diet containing 28% protein. Increasing feeding rate increased visceral fat but had no major effect on carcass, fillet, and nugget yields. Fish fed to satiation contained less moisture and more fat in the fillets that those fed a restricted ration. Nitrogenous waste compounds were generally higher where the fish were fed the higher protein diets. Although there was a significant interaction in pond water chemical oxygen demand between dietary protein and feeding rate, generally ponds in the satiation feeding group had higher chemical oxygen demand than ponds in the restricted feeding group. There was a trend that pond water total phosphorus levels were slightly elevated in the satiation feeding group compared to the restricted feeding group. However, pond water soluble reactive phosphorus and chlorophyll-a were not affected by either diet or feeding rate. Results from the present study indicate that a 28% protein diet provides the same level of channel catfish production as a 40% protein diet even when diet is restricted to 90 kg/ha per d. Although there was an increase in nitrogenous wastes in ponds where fish were fed high protein diets, there was little effect on fish production. The long term effects of using high protein diets on water quality are still unclear. Feeding to less than satiety may be beneficial in improving feed efficiency and water quality.     

Effects of Feeding Diets with and without Fish Meal on Production of Channel Catfish,Ictalurus punctatus,Stocked at Varying Densities

ABSTRACT

Animal protein, generally fish meal, has traditionally been used in the diet of channel catfish. However, our previous research indicates that animal protein is not needed for growing stocker-size catfish to food fish when the fish are stocked at densities typical of those used in commercial catfish culture. Whether this holds when fish are stocked at high densities is not known; thus, we conducted an experiment to evaluate the effect of feeding diets with and without fish meal to channel catfish stocked in earthen ponds at different densities. Two 32% protein-practical diets containing 0% or 6% menhaden fish meal were compared for pond-raised channel catfish, Ictalurus punctatus, stocked at densities of 14,820, 29,640, or 44,460 fish/ha. Fingerling channel catfish with average initial weight of 48 g/fish were stocked into 30 0.04-ha ponds. Five ponds were randomly allotted for each fish meal level?×?stocking density combination. Fish were fed once daily to satiation for two growing seasons. There was a significant interaction between stocking density and fish meal for net production; net production increased in fish fed a diet containing fish meal compared with those fed an all-plant diet at the highest stocking density, but not at the two lower stocking densities. Net production of fish fed diets with and without fish meal increased as stocking density increased. Viewing the main effect means, weight gain decreased and feed conversion ratio increased for fish stocked at the two highest densities, and survival was significantly lower at the highest stocking density. Visceral fat decreased in fish at the two highest stocking densities. Body composition data were largely unaffected by experimental treatment except for a reduction in percentage filet fat in fish at the highest stocking density, and fish that were fed diets containing fish meal had a lower percentage fillet protein and a higher percentage fillet fat. It appears that at stocking densities two to three times higher than generally used, animal protein (fish meal) may be beneficial in the diet of channel catfish. In regard to stocking densities, high stocking results in higher overall production, but the average fish size decreased as stocking density increased.