Practical Diets (practical + diet)

Distribution by Scientific Domains


Selected Abstracts


Evaluation of Alternative Protein Sources to Replace Fish Meal in Practical Diets for Juvenile Tilapia, Oreochromis spp

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2009
Tri N. Nguyen
Two feeding experiments were conducted to evaluate if methionine is limiting in practical grow-out diets for tilapia, Oreochromis spp. Four diets containing 32% protein and 5% lipid were designed to compare the use of diets high in dehulled solvent-extracted soybean meal (DSESM) and expeller pressed soybean meal (EPSM) compared with a diet containing 6% fish meal (FM). Tilapia (4.78 ± 0.07 g, mean ± SD) were randomly stocked into twelve 600-L flow-through tanks at 20 fish per tank. After 6 wk, there were no notable trends or statistically significant differences (P > 0.05) in final mean weight, survival rate, and feed conversion ratio (FCR) among the treatments. Because results of this study indicated that DSESM could totally replace FM in practical diets for juvenile tilapia, a second batch of diets were formulated using other protein sources. Typical levels of cottonseed meal (CSM), DSESM, and meat and bone meal (MBM) were used to evaluate whether methionine could be limiting. Two basal diet formulations were tested either without or with methionine supplement (0.06/100 g diet). The first diet contained 15% CSM, 27% DSESM, and 10% MBM and the second diet contained 15% CSM and 37% DSESM. These diets contained 28% protein and 5% lipid. Tilapia (3.90 ± 0.05 g) were randomly stocked into twelve 60-L glass aquaria of a recirculation system at 18 fish per aquarium for 5 wk and then moved to the 600-L flow-through tanks for five more weeks. After 10 wk, there were no statistically significant differences (P > 0.05) in final mean weight, survival rate, and FCR among the four treatments. Results of the present study indicated that DSESM and EPSM could totally replace FM's inclusion rate in commercial diets for juvenile tilapia. Furthermore, methionine did not appear to be limiting in practical diets using typical levels of CSM, DSESM, and MBM as primary protein sources. [source]


Evaluation of Experimental and Practical Diets for Walleye Stizostedion vitreum

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2002
Anant S. Bharadwaj
Culture of walleye Sfizostedion vitreum is one of the largest components of public sector aquaculture in the eastern U.S. and there is increasing interest in private sector culture. However, the nutritional requirements of walleye are unknown and experimental diets for use in quantifying nutritional requirements have not been identified. We formulated four experimental and four practical diets and fed those to triplicate groups of walleye with an initial weight of 13 g per fish. The experimental diets contained either casein (CAS), casein + gelatin (CG), casein + arginine (CA), or casein + gelatin + crystalline amino acids (CGAA) as sources of amino acids. The practical diets were formulated to mimic salmon grower (SG) and trout grower (TG) diets, a fish meal-free diet for trout (TFMF), and a walleye grower (WG) diet. Fish were fed twice daily to satiation for 9 wk. Feed consumption, percent weight gain, specific growth rates, feed efficiency, protein efficiency ratio, and protein retention efficiency were not significantly different among fish fed CGAA, SG, and TG, but those values were significantly higher than in fish fed other diets. Weight gain of fish fed CGAA was approximately 80% of that in fish fed SG and 91% of that in fish fed TG. Protein retention efficiency of fish fed CGAA was approximately 69% and 81% of that observed for fish fed SG, and TG, respectively. In general, the carcasses of fish fed diets CGAA, SG and TG had significantly lower moisture and ash concentrations, and higher lipid levels than fish fed other diets. There were no significant differences in carcass protein concentration, muscle proximate composition, or liver lipid concentration among treatments. Livers from fish fed all diets were characterized by microvesicular degeneration and glycogen accumulation in hepatocytes. Results from the study indicate that CGAA can be used as a basal experimental diet in future nutritional research with juvenile walleye and confirms the benefits of trout and salmon grower diets. Fish meal-free diets formulated around the requirements for rainbow trout were consumed at approximately 80% of the values in fish fed TG and SG, but weight gain was approximately 20% of that in fish fed TG and SG. It appears the nutritional requirements for walleye are different than those of rainbow trout. [source]


Bioavailability of Ascorbyl-2-Monophosphate to Channel Catfish Fed Purified and Practical Diets

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2002
Wendy M. Sealey
[source]


Nutritional value of feed peas (Pisum sativum) in practical diet formulations for Litopenaeus vannamei

AQUACULTURE NUTRITION, Issue 2 2002
D.A. DAVIS
Dry peas of mixed Canadian prairie varieties which were commercially obtained and processed to provide a variety of meals were evaluated in practical shrimp feeds. Whole and de-hulled peas were pin milled to produce raw flours. A portion of these meals were processed to produce whole extruded and de-hulled extruded meals. Additionally, a portion of the whole pea meal was processed by infrared cooking to produce a micronized meal. The five meals were evaluated in practical diets for Litopenaeus vannamei under controlled laboratory conditions. The first experiment was designed to estimate apparent protein and energy availability of the various meals. Using a practical reference diet, the meals were substituted using a 70:30 ratio to produce the test diets. Based on contrasts, both extruding and micronizing the pea meals resulted in significant improvements in both apparent protein digestibility and apparent energy digestibility values. Apparent energy digestibility values for the various ingredients expressed as percentage ± SD were: whole raw, 72.3 ± 8.1; whole extruded, 86.0 ± 8.9; de-hulled raw, 88.4 ± 4.4; de-hulled extruded, 94.4 ± 10.0; whole micronized, 94.1 ± 10.2. To evaluate the response of shrimp to the diets containing pea meal, two 7-week growth trials were conducted in the laboratory using a practical diet formulated to contain 360 g kg,1 protein and 90 g kg,1 lipid. In the first growth trial the shrimp had a mean initial weight of 0.66 g and six test diets were evaluated that included the basal diet and five diets for which the pea meals were included in the diet at 250 g kg,1 dry weight replacing whole wheat. In the second growth trial the shrimp had a mean initial weight of 1.1 g and only the whole raw and whole extruded meals were evaluated at 50, 100 and 200 g kg,1 inclusion in the diet. At the conclusion of the first growth trial weight gain ranged from 718 to 862% and at the conclusion of the second growth trial weight gain ranged from 394 to 502%, with no significant differences or discernible trends observed as a result of the various dietary treatments. Based on the observed results, the continued evaluation of feed peas as a potential ingredient of shrimp feeds is warranted. Additionally, if feed peas are suitably priced, commercial producers are encouraged to evaluate feed peas as an alternative protein and energy source. [source]


Use of commercial fermentation products as a highly unsaturated fatty acid source in practical diets for the Pacific white shrimp Litopenaeus vannamei

AQUACULTURE RESEARCH, Issue 7 2010
Tzachi M Samocha
Abstract Removal or reduction of marine ingredients (MI) from feed formulations is critical to the sustainability of the aquaculture industry. By removing MI, diets may become limiting in several nutrients including highly unsaturated fatty acids (HUFA) such as docosahexaenoic acid (DHA) and arachidonic acid (ArA). To reduce reliance on MI in shrimp diets, two trials were conducted with Litopenaeus vannamei juveniles to determine the feasibility of using fermentation meals rich in DHA and ArA as the primary source for HUFA. A practical diet with no MI was formulated with/without DHA and ArA supplements and fed in the first trial. A diet with menhaden fish oil or a combination of plant oil with/without DHA and ArA supplements was used in the second trial. To determine whether HUFA is only needed in the early growth stages, we also fed one group a HUFA-supplemented diet to 5 g and then switched them to a HUFA-supplement-free diet. In both trials, the weights were reduced when HUFA supplements were not provided either throughout the trial or from 5 g to harvest (<16 g). These results suggest that supplementation of plant oils with DHA- and ArA-rich oils from fermented products is a viable option to replace marine fish oil for L. vannamei. [source]


Effects of feeding levels on growth performance, feed utilization, body composition and apparent digestibility coefficients of nutrients for juvenile Chinese sucker, Myxocyprinus asiaticus

AQUACULTURE RESEARCH, Issue 7 2010
Yong-Chao Yuan
Abstract An experiment was conducted to determine effects of feeding levels on growth performance, feed utilization, nutrient deposition, body composition and apparent digestibility coefficients (ADCs) of nutrients for juvenile Chinese sucker (initial weight, 11.77±0.22 g). Chinese sucker were fed a practical diet from 0% (starvation) to 4.0% (at 0.5% increments) body weight (bw) day,1 for 8 weeks. The results showed that growth performance, feed utilization, nutrient deposition, body composition and ADCs of dry matter, protein and energy were significantly (P<0.05) affected by feeding levels. Survival was the lowest for the starvation group. Final mean body weight, growth rate, thermal-unit growth coefficient (TGC) increased with feeding rate from 0% to 3.0% bw day,1 (P<0.05) and showed no significant differences above the level (P>0.05). Feed conversion rate was significantly lower at a feeding level of 2.5% bw day,1 than above and below the level (P<0.05). Protein efficiency ratio was markedly highest at the 2.5% bw day,1 ration level (P<0.05). Fish fed at the feeding level (1.0% bw day,1), which represented a maintenance ration (energy gain was less than 2.27 kJ fish,1 day,1), showed positive protein deposition but negative lipid deposition. This indicates that fish fed a maintenance ration mobilize body lipid reserve to support protein deposition. Lipid contents of whole body, muscle and liver increased with increasing feeding rates from 0.5% to 3.0% bw day,1 and showed no significant differences above the level (P>0.05). Protein contents of whole-body composition increased with feeding rate from 0.5 to 3.0% bw day,1 (P<0.05) and showed no significant differences above the level (P>0.05), whereas muscle and liver remained relatively stable with the different ration amount with the exception of fish fed a ration of 0.5% bw day,1, at which Chinese sucker possessed significantly lower body protein concentration (P<0.05). The ADCs of dry matter, protein and energy decreased with increasing feeding levels from 0.5% to 3.0% bw day,1 and then remained relatively constant over the level. Based on the broken-line regression analysis using WG data, the optimum and maintenance feeding levels for Chinese sucker were 3.10% bw day,1 and 0.45% bw day,1 respectively. [source]


Effects of temperature, density and early weaning on the survival and growth of Atlantic ditch shrimp Palaemonetes varians larvae

AQUACULTURE RESEARCH, Issue 13 2009
Jorge Palma
Abstract This investigation examined the effects of temperature, density and early weaning on the survival and growth of Palaemonetes varians larvae. Survival of larvae raised at 17.5 °C was not significantly different (average + standard deviation) (94 ± 5%) from the survival of those raised at 19.5 °C (95 ± 5%) and at 21.5 °C (94 ± 4%). However, the duration of the larval stage was significantly longer for shrimp reared at 17.5 °C (17.3 ± 0.8 days) compared with shrimp reared at 19.5 °C (14.3 ± 0.7 days) and at 21.5 °C (11.3 ± 0.6 days). No significant differences (P>0.05) were found in the survival rate, final weight and length of larvae reared at the densities of 5, 10, 20 and 50 larvae L,1. The survival of P. varians larvae fed solely on Artemia was significantly higher (P<0.05) than larvae weaned with an artificial practical diet from Zoea II stage (94 ± 4% and 82 ± 1%, respectively, for Artemia and artificial diet-fed larvae), but no significant differences (P>0.05) were observed in the final larval weight or length between these two treatments. The survival and growth of the larvae fed with the practical diet tested is a promising step ahead in the development of the culture of this species as it eliminates both the need for Artemia throughout all larval stages, and the need for more expensive artificial diets. [source]


Terrestrial leaf meals or freshwater aquatic fern as potential feed ingredients for farmed abalone Haliotis asinina (Linnaeus 1758)

AQUACULTURE RESEARCH, Issue 8 2003
Ofelia S Reyes
Abstract Three terrestrial leaf meals, Carica papaya, Leucaena leucocephala, Moringa oliefera and a freshwater aquatic fern, Azolla pinnata were evaluated as potential ingredients for farmed abalone diet. All diets were formulated to contain 27% crude protein, 13% of which was contributed by the various leaf meals. Fresh seaweed Gracilariopsis bailinae served as the control feed. Juvenile Haliotis asinina (mean body weight=13.4±1.6 g, mean shell length= 38.8±1.4 mm) were fed the diets at 2,3% of the body weight day,1. Seaweed was given at 30% of body weight day,1. After 120 days of feeding, abalone fed M. oliefera, A. pinnata -based diets, and fresh G. bailinae had significantly higher (P<0.01) specific growth rates (SGR%) than abalone fed the L. leucocephala- based diet. Abalone fed the M. oliefera -based diet had a better growth rate in terms of shell length (P<0.05) compared with those fed the L. leucocephala -based diet but not with those in other treatments. Furthermore, protein productive value (PPV) of H. asinina was significantly higher when fed the M. oliefera -based diet compared with all other treatments (P<0.002). Survival was generally high (80,100%) with no significant differences among treatments. Abalone fed the M. oliefera -based diet showed significantly higher carcass protein (70% dry weight) and lipid (5%) than the other treatments. Moringa oliefera leaf meal and freshwater aquatic fern (A. pinnata) are promising alternative feed ingredients for practical diet for farmed abalone as these are locally available year-round in the Philippines. [source]


Estimating digestible protein requirements of silver perch, Bidyanus bidyanus Mitchell

AQUACULTURE RESEARCH, Issue 5 2001
G L Allan
Abstract In this study, we estimated requirements for digestible protein, using intact protein sources, at one digestible energy content. Using digestibility data for silver perch (Bidyanus bidyanus Mitchell) for a large number of ingredients, we formulated a ,summit' diet to contain between 1.4 and 1.8 times the ,expected requirements' for digestible essential amino acids (based on requirements for channel catfish, Ictalurus punctatus Rafinesque). A ,diluent' diet was formulated to contain 0.4,0.5 times the expected requirements of digestible essential amino acids. Both ,summit' and ,diluent' diets contained similar digestible energy (14.7 MJ digestible energy kg,1 for the summit and 13.4 MJ digestible energy kg,1 for the diluent). Six diets were prepared with the following amounts of summit,diluent diets: 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100. A practical diet widely used by commercial farmers was also included as a control. Ten juvenile fish (2.1,2.6 g) were stocked into each experimental 70-L acrylic aquarium, and each dietary treatment was randomly assigned to five replicate aquaria. Fish were fed twice daily to apparent satiation for 54 days. Final individual fish weight ranged from 4,15.5 g. Results were analysed using intersecting linear regression analysis. The optimum digestible dietary protein for diets with 13.4,14.7 MJ digestible energy kg,1, after which protein deposition did not increase significantly, was 28%. Although this study did not determine requirements for individual amino acids, for diets with the digestible energy content used here, requirements for individual amino acids obviously did not exceed the content in the 28% protein diet. These contents are useful as an estimate of ,recommended levels' for silver perch diets with 13.4,14.7 MJ digestible energy kg,1. The proximate composition of fish was affected by diet. Whole body protein and moisture increased, whereas lipid content decreased with increasing dietary protein content (and increasing protein,energy ratio and decreasing lipid). Fish size was also affected by diet; however, the changes in whole carcass proximate composition also occurred for fish fed diets 60:40, 80:20 and the summit diet which were a similar final weight. [source]


Fermentation characteristics and microbial growth promoted by diets including two-phase olive cake in continuous fermenters

JOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1 2008
A. Moumen
Summary Two-phase olive cake (2POC) is the by-product obtained from the so called ,two-phase' procedure to extract olive oil by mechanical methods. After the mechanical extraction the 2POC is dried and most of the remaining oil extracted by chemical means. The production of the crude by-product may reach more than 4 millions t/year in Spain (MAPA, 2003), most of it in areas (Southeast) with shortage of pastures and conventional feeds for ruminants. Six continuous fermenters, inoculated with ruminal liquor from wethers or goats, were fed lucerne hay (LH); LH plus a concentrate including dried two-phase olive cake (LHCO) and; diet LHCO added with polyethylene glycol (LHCOP). The highest pH values and ammonia N (NH3 -N) output were found in fermenters fed diet LH (6.19 and 6.35 for pH, and 53.7 and 68.9 mg NH3N/day, respectively, in fermentes inoculated with rumen liquor from sheep and goats) without differences due to the inoculum origin. The digestibility of carbohydrates (CHO) was affected (p < 0.001) by inoculum (67.0 and 58.8%, respectively, for goats and wethers) the lowest values being for diet LHCO (53.2 and 57.0% with inoculum from wethers and goats, respectively). The main volatile fatty acid (VFA) was acetic acid with higher (p < 0.01) values in fermenters with inoculum from goats than from wethers (80.2 and 63.0 mmol/day respectively). The efficiency of bacterial protein synthesis (EBS) was not different (p > 0.05) with inoculum from wethers and goats [26.4 and 28.1 and 35.2 and 33.5 g bacterial N/kg digested CHO, respectively, obtained by using diamino pimelic acid (DAPA) and purine bases (PB) as microbial markers]. The lowest (p < 0.05) values were found in fermenters fed diets LHCOP and LH, estimated, respectively, from DAPA and PB (21.9 and 29.0 g bacterial N/kg digested CHO). The substitution of a part of lucerne hay by a concentrate including dried 2POC does not seem to cause important differences in efficiency of VFA production. Results concerning bacterial protein synthesis are not so clear since values estimated from DAPA and PB did not show similar trends. Neither inoculum origin nor PEG had important effects on fermentation characteristics. The DAPA could be an adequate marker in continuous fermenters, with comparative purposes, as protozoa are not present and, estimated protein synthesis values are similar to those obtained in vivo with similar diets using urinary excretion of PD (Yáñez Ruiz et al., 2004b). Further research is needed to state the optimal proportion of 2POC in practical diets for ruminants at both maintenance and production stages. [source]


Nutritional evaluation of various plant protein sources in diets for Asian sea bass Lates calcarifer

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2000
By P. S. Eusebio
A biological assay was conducted to evaluate the suitability of various leguminous seed meals and leaf meals as dietary protein sources for Asian sea bass, Lates calcarifer. In the growth experiment, fish (initial mean weight ±,standard error (SE) of 3.8 ± 0.5 g) were fed isonitrogenous and isocaloric diets containing test ingredients to replace 13,18% of the diet. The same diet formulations were used in a digestibility experiment, except that 1% Cr2O3 was added as an external indicator. The growth of the control fish was comparable to fish fed leguminous seed meal-based diets, and better than those given leaf meal-based diets. The control diet had the highest apparent protein digestibility (APD) value. No significant differences were observed between the APD of white cowpea (Vigna unguiculata), green mungbean (V. radiata) and papaya (Carica papaya) leaf meal-based diets. However, the cassava (Manihot esculenta) leaf meal-based diet had the lowest APD value. The present findings suggest that white cowpea and green mungbean meals can be used as protein sources in practical diets to replace 18% of the sea bass diet without affecting their growth. [source]


Evaluation of Glycerol from Biodiesel Production as a Feed Ingredient for Channel Catfish, Ictalurus punctatus

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2010
Menghe H. Li
Glycerol is the main by-product of biodiesel production from vegetable oils and animal fats. It has been evaluated as an energy source for several farm animals. A study was conducted to examine the effects of various levels of glycerol in channel catfish, Ictalurus punctatus, diets. Fish with mean initial weight of 6.8 ± 0.1 g were stocked in 110-L flow-through aquaria and fed practical diets containing 0, 5, 10, 15, and 20% glycerol for 9 wk. There were no significant differences in feed consumption, weight gain, feed efficiency ratio, and liver lipid level among fish fed diets containing 0, 5, and 10% glycerol. However, fish fed diets containing 15 and 20% glycerol had reduced weight gain, feed efficiency, and liver lipid content. Survival was not affected by dietary glycerol levels. Blood glucose level was significantly higher in fish fed 5% glycerol than fish fed other diets. Fillet protein and fat generally decreased and fillet moisture increased as dietary glycerol level increased. It appears that channel catfish can utilize about 10% glycerol in the diet without adverse effects on feed consumption, weight gain, feed efficiency ratio, hemoglobin, hepatosomatic index, and liver lipid. [source]


Effects of Carbohydrate-Rich Alternative Feedstuffs on Growth, Survival, Body Composition, Hematology, and Nonspecific Immune Response of Black Pacu, Colossoma macropomum, and Red Pacu, Piaractus brachypomus

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2009
Rebecca Lochmann
To facilitate economical culture of black pacu, Colossoma macropomum, and red pacu, Piaractus brachypomus, in the Amazon region of South America, we assessed locally available alternative energy sources for practical diets. We tested the effects of control diets (containing wheat products) versus diets with different Amazonian feedstuffs (yucca, Manihot sculenta, plantain, Musa paradisiaca, or pijuayo, Bactris gasipaes) on the performance of the pacus in three feeding trials. Black pacu (22.5 ± 0.03 g; Trial 1) or red pacu (2.56 ± 0.01 g; Trial 2) were fed diets containing 30% wheat bran (control) or cooked or uncooked yucca, plantain, or pijuayo for 12 wk. In Trial 3, larger black pacu (86.9 ± 6.4 g) were grown to market size in 24 wk on similar diets. Weight gain, feed conversion, survival, alternative complement activity, and lysozyme were similar among diets. Hepatosomatic index, liver glycogen, and dry matter were affected by diet in Trials 1 and 2, but effects were not consistent among trials. In Trial 3, protein efficiency ratio was lower in fish fed the diet containing wheat middlings. However, relative to wheat bran or wheat middlings, all feedstuffs tested were effective energy sources for juvenile black pacu and red pacu. [source]


Evaluation of Alternative Protein Sources to Replace Fish Meal in Practical Diets for Juvenile Tilapia, Oreochromis spp

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2009
Tri N. Nguyen
Two feeding experiments were conducted to evaluate if methionine is limiting in practical grow-out diets for tilapia, Oreochromis spp. Four diets containing 32% protein and 5% lipid were designed to compare the use of diets high in dehulled solvent-extracted soybean meal (DSESM) and expeller pressed soybean meal (EPSM) compared with a diet containing 6% fish meal (FM). Tilapia (4.78 ± 0.07 g, mean ± SD) were randomly stocked into twelve 600-L flow-through tanks at 20 fish per tank. After 6 wk, there were no notable trends or statistically significant differences (P > 0.05) in final mean weight, survival rate, and feed conversion ratio (FCR) among the treatments. Because results of this study indicated that DSESM could totally replace FM in practical diets for juvenile tilapia, a second batch of diets were formulated using other protein sources. Typical levels of cottonseed meal (CSM), DSESM, and meat and bone meal (MBM) were used to evaluate whether methionine could be limiting. Two basal diet formulations were tested either without or with methionine supplement (0.06/100 g diet). The first diet contained 15% CSM, 27% DSESM, and 10% MBM and the second diet contained 15% CSM and 37% DSESM. These diets contained 28% protein and 5% lipid. Tilapia (3.90 ± 0.05 g) were randomly stocked into twelve 60-L glass aquaria of a recirculation system at 18 fish per aquarium for 5 wk and then moved to the 600-L flow-through tanks for five more weeks. After 10 wk, there were no statistically significant differences (P > 0.05) in final mean weight, survival rate, and FCR among the four treatments. Results of the present study indicated that DSESM and EPSM could totally replace FM's inclusion rate in commercial diets for juvenile tilapia. Furthermore, methionine did not appear to be limiting in practical diets using typical levels of CSM, DSESM, and MBM as primary protein sources. [source]


Replacement of Fish Meal with Soybean Meal in the Production Diets of Juvenile Red Snapper, Lutjanus campechanus

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2005
D. Allen Davis
The replacement of fish meal with soybean meal in fish diets has met with varying degrees of success. Quite often, poor responses to high soybean meal diets are either due to shifts in the nutrient profile or a reduced palatability of the diet when fish meal is removed. The present research was designed to evaluate the replacement of menhaden fish meal with solvent-extracted soybean meal in practical diets containing 10% poultry by-product meal and formulated to contain 40% protein, 8% lipid, and a total sulfur amino acid content of > 3.0% of the protein. The response of red snapper (mean initial weight 10.9 g) to diets containing graded levels of fish meal (30,20, 10, 0%) as well as the response to a low fish meal diet (10%) without poultry by-product meal were evaluated over a 6-wk growth period. Significant (P± 0.05) differences in final mean weight, percent weight gain, and feed conversion were observed. Final weights (percent gain) ranged from 30.9 g (185.5%) for fish offered diets with 30% fish meal to 12.6 g (16.3%) for fish offered diets with 0% fish meal. Corresponding feed conversion efficiencies ranged from 60.1% to 7.7%. No significant differences were observed for survival between treatment means. Although there was a clear reduction in performance as the fish meal was replaced with soybean meal, the use of 10% poultry by-product meal or 10% fish meal resulted in similar performance of the fish. This is a good indication that poultry by-product meal does not have palatability problems and could be used as a substitute. The present findings suggest that replacing fish meal with high levels of soybean meal appears to reduce the palatability of the diet. While the cost reducing benefit, with respect to the replacement of fish meal, has been shown with other species, before high levels of inclusion can be efficiently utilized further research is needed to address the palatability problems observed with red snapper. [source]


Evaluation of Experimental and Practical Diets for Walleye Stizostedion vitreum

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2002
Anant S. Bharadwaj
Culture of walleye Sfizostedion vitreum is one of the largest components of public sector aquaculture in the eastern U.S. and there is increasing interest in private sector culture. However, the nutritional requirements of walleye are unknown and experimental diets for use in quantifying nutritional requirements have not been identified. We formulated four experimental and four practical diets and fed those to triplicate groups of walleye with an initial weight of 13 g per fish. The experimental diets contained either casein (CAS), casein + gelatin (CG), casein + arginine (CA), or casein + gelatin + crystalline amino acids (CGAA) as sources of amino acids. The practical diets were formulated to mimic salmon grower (SG) and trout grower (TG) diets, a fish meal-free diet for trout (TFMF), and a walleye grower (WG) diet. Fish were fed twice daily to satiation for 9 wk. Feed consumption, percent weight gain, specific growth rates, feed efficiency, protein efficiency ratio, and protein retention efficiency were not significantly different among fish fed CGAA, SG, and TG, but those values were significantly higher than in fish fed other diets. Weight gain of fish fed CGAA was approximately 80% of that in fish fed SG and 91% of that in fish fed TG. Protein retention efficiency of fish fed CGAA was approximately 69% and 81% of that observed for fish fed SG, and TG, respectively. In general, the carcasses of fish fed diets CGAA, SG and TG had significantly lower moisture and ash concentrations, and higher lipid levels than fish fed other diets. There were no significant differences in carcass protein concentration, muscle proximate composition, or liver lipid concentration among treatments. Livers from fish fed all diets were characterized by microvesicular degeneration and glycogen accumulation in hepatocytes. Results from the study indicate that CGAA can be used as a basal experimental diet in future nutritional research with juvenile walleye and confirms the benefits of trout and salmon grower diets. Fish meal-free diets formulated around the requirements for rainbow trout were consumed at approximately 80% of the values in fish fed TG and SG, but weight gain was approximately 20% of that in fish fed TG and SG. It appears the nutritional requirements for walleye are different than those of rainbow trout. [source]


Performance of Juvenile Coho Salmon Oncorhynchus kisutch Fed Diets Containing Meals from Fish Wastes, Deboned Fish Wastes, or Skin-and-Bone By-Product as the Protein Ingredient

JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2001
Cindra K. Rathbone
The suitability of meals derived from fish processing wastes as the protein fraction in practical diets for hatchery-reared coho salmon was investigated. The study compared the performance of coho salmon fed diets containing three products: a skin-and-bone meal (SB), a deboned meal (DM), and a whole-fish meal (WM) made directly from the fish wastes. A commercial trout diet (CO) was fed to a fourth treatment group. Diets were fed at 3% of body weight per day to juvenile coho salmon for 12 wk. Survival (> 94%) was not significantly different among treatment groups. Average fish weight, feed conversion ratio, whole body proximate and mineral composition, and protein and phosphorus retention were compared. There were no significant differences after 12 wk of feeding in fish weight between WM, DM, and CO, but SB had significantly lower weight and whole body lipid, and significantly higher ash. Compared to WM, DM had a significantly lower feed conversion ratio and higher retention of protein and phosphorus, but these indices were not significantly different from CO. It is concluded that DM is a potentially superior protein ingredient compared to WM, while specific characteristics of SB will limit its use as a protein source in feeds for salmonids. However, SB may prove to be a suitable mineral supplement when added at a low level. Utilization of fish processing wastes in salmonid diets could be a commercially viable alternative to direct disposal of processing wastes. [source]


Effects of dietary protein and lipid levels on growth and energy productive value of pacific white shrimp, Litopenaeus vannamei, at different salinities

AQUACULTURE NUTRITION, Issue 4 2010
X.Z. ZHU
Abstract A 8-week feeding experiment was conducted to evaluate the effect of different dietary protein and lipid levels on growth and energy productive value of juvenile Litopenaeus vannamei, at 30 and 2 ppt, respectively. Nine practical diets were formulated to contain three protein levels (380, 410 and 440 g kg,1) and three lipid levels (60, 80 and 100 g kg,1). Each diet was randomly fed to triplicate groups of 30 shrimps per tank (260 L). The effects of salinity and an interaction between dietary protein level and lipid level on growth and energy productive value of shrimp were observed under the experimental conditions of this study. At 30 ppt seawater, shrimp fed with 440 g kg,1protein diets had significantly higher weight gain (WG) than those fed with 380 g kg,1 protein diets at the same dietary lipid level, and the 60 g kg,1 lipid group showed higher growth than 80 g kg,1and 100 g kg,1 lipid groups at the same dietary protein level. At 2 ppt seawater, the growth of shrimp was little affected by dietary protein treatments when shrimp fed the 80 and 100 g kg,1 lipid, shrimp fed the 80 g kg,1 lipid diets had only slightly higher growth than that fed 60and 100 g kg,1 lipid diets when fed 380 and 410 g kg,1 dietary protein diets. A significant effect of salinity on growth of shrimp was detected with the growth responses at 30 ppt > 2ppt (P < 0.05). Final body lipid content, body protein content and energy productive value of shrimp was significantly higher in animals exposed to 30 ppt than in shrimp held at 2 ppt. [source]


Effects of dietary protein level on growth, feed utilization and digestive enzyme activity of the Chinese mitten crab, Eriocheir sinensis

AQUACULTURE NUTRITION, Issue 3 2010
S. LIN
Abstract A feeding trial was conducted using isoenergetic practical diets to evaluate the effects of the dietary protein level on growth performance, feed utilization and digestive enzyme activity of the Chinese mitten crab, Eriocheir sinensis. Four experimental diets were formulated containing 250, 300, 350 and 400 g kg,1 protein and 16 kJ g,1 gross energy. Each diet was randomly assigned to triplicate groups of juvenile crab with mean initial body weight 3.56 ± 0.16 g and mean shell width 15.31 ± 0.06 mm. Juvenile crab were reared in indoor flow-through system consisting of 12 plastic tanks (1.0 m × 0.6 m × 0.5 m) and fed diets twice daily at 6,8% of body weight for 12 weeks. Performance was judged on the basis of growth (specific growth rate of weight, SGRG; specific growth rate of shell width, SGRSW), feed conversion ratio (FCR) and protein efficiency ratio (PER). A decreased FCR was observed with increasing dietary protein levels. Both SGRG and SGRSW significantly increased with increasing dietary protein levels up to 350 g kg,1, whereas there were no significant differences for protein levels from 350,400 g kg,1. Application of broken line regression analysis to SGRG provided an estimate of 347.8 g kg,1 dietary protein for maximal growth. The highest PER was observed in crab fed the diet containing 350 g kg,1 protein (P < 0.05). The percent survival was not affected (P > 0.05) by the different dietary treatments. No significant differences were observed in the apparent digestibility coefficients of crude lipid and dry matter among dietary treatments (P > 0.05). However, the apparent digestibility coefficients of crude protein and energy in crab fed different protein levels significantly increased with increasing dietary protein level (P < 0.05). Both amylase and protease activities in the intestine of E. sinensis were studied. The amylase activity decreased significantly (P < 0.05) with increased dietary protein level and protease activity increased. Regression analysis showed a negative effect of inclusion of dietary protein level on amylase activity (P < 0.05). However, protease activities were found to be positively correlated (P < 0.05) with dietary protein level. The protein content of the crab significantly increased with dietary protein levels up to 350 g kg,1 (P < 0.05), but no significant differences (P > 0.05) were founded with protein levels higher than 350 g kg,1. [source]


Influence of dietary protein levels on growth performance and body composition of African bonytongue fingerlings, Heterotis niloticus (Cuvier, 1829)

AQUACULTURE NUTRITION, Issue 2 2010
S.-E. MONENTCHAM
Abstract Two experiments were conducted to examine the influence of dietary protein levels on growth and carcass proximate composition of Heterotis fingerlings. Four isoenergetic practical diets were formulated to contain dietary protein levels from 250 to 400 g kg,1 diet. Replicate groups of young Heterotis (initial live weight 3.96 and 26.40 g in experiments 1 and 2 respectively) were handfed twice daily to apparent satiation for a period of 42 and 28 days respectively. Statistical analysis revealed that growth rate was significantly affected by dietary protein level (P < 0.01). The highest weight gain was observed in fingerlings fed with 300 and 350 g protein kg,1 diet for fish size ranging between 3,15 and 26,62 g respectively. There was no significant difference between groups fed with 300, 350 and 400 g protein kg,1 diet for Heterotis fingerlings (3,15 g) in the one hand; in the other hand, significant differences were found between fish (26,62 g) fed with 350 g protein kg,1 diet and those receiving 300 and 400 g protein kg,1 diet, with no significant difference between each other. The specific growth rate varied from 2.4% to 3.1% day,1. The whole-body protein, lipid, moisture and ash contents were not significantly affected by dietary protein levels (P > 0.05). The relationships between percentage weight gain and dietary protein levels suggested very similar dietary protein requirement (about 310 g crude protein kg,1 diet) for Heterotis ranging from 3 to 62 g. The maximum growth occurred at about 345 g protein kg,1 diet. [source]


Effect of practical diets with different protein levels on the performance of Farfantepenaeus paulensis juveniles nursed in a zero exchange suspended microbial flocs intensive system

AQUACULTURE NUTRITION, Issue 2 2010
E.L.C. BALLESTER
Abstract Farfantepenaeus paulensis juveniles (72 ± 24 mg), were reared in a suspended microbial flocs system and fed practical diets containing increasing amounts of crude protein (250, 300, 350, 400 and 450 g kg,1 CP). Development of microbial flocs was promoted by high aeration rates and fertilization with wheat bran and molasses. Flocs were composed of detritus in the form of flocculated matter colonized by heterotrophic bacteria, cocoid and filamentous cyanobacteria, flagellate and ciliate protozoa and rotifers. Proximate composition analysis of the suspended microbial floc showed CP levels of 304 g kg,1. After 45 days, mean shrimp survival were above 89%, with no significant differences between treatments. Shrimp fed diets with 350 g kg,1 or higher CP content achieved significant higher (P < 0.05) final weight (0.66,0.68 g), weight gain (0.58,0.61 g) and instantaneous growth rate (0.049,0.050), with feed conversion rates (2.17,2.30) significantly lower (P < 0.05). Results show that, when rearing is carried out in a suspended microbial flocs system, dietary CP levels can be kept at 350 g kg,1. Furthermore, results confirm that microbial-based systems allow shrimp culture without compromising the surrounding environment and shows the possible reduction of production costs and fish meal dependence. [source]


Effects of various corn distillers by-products on growth, feed efficiency, and body composition of channel catfish, Ictalurus punctatus

AQUACULTURE NUTRITION, Issue 2 2010
M.H. LI
Abstract A study was conducted to examine the use of corn distillers' by-products in diets and the effects of additional dietary fat on channel catfish, Ictalurus punctatus, performance. Juvenile channel catfish (initial weight: 12.6 g per fish) were stocked in flow-through aquaria and fed one of six practical diets for 9 weeks. Fish fed the control + fat diet consumed more diet and had higher feed efficiency ratio (FER) than fish fed the control diet, but weight gain was not significantly different between fish fed these two diets. Fish fed the diet containing 300 g kg,1 distillers dried grains with solubles (DDGS) consumed more diet and gained more weight, but had similar FER compared with fish fed the control + fat diet. The diet containing 200 g kg,1 high-protein distillers grains (HPDDG) resulted in similar diet consumption, weight gain and FER as the control + fat diet. Fish fed the diet containing 100 g kg,1 distillers solubles (DS) consumed more diet, but had similar weight gain and FER compared with fish fed the 300 g kg,1 DDGS diet. The presence of distillers solubles in the diet (300 g kg,1 DDGS, 100 g kg,1 DS, 100 g kg,1 EDS diets) appears to increase diet consumption, weight gain, and FER over the control diets with or without additional fat. [source]


Effects of dietary protein to energy ratios on growth and body composition of juvenile Chinese sucker, Myxocyprinus asiaticus

AQUACULTURE NUTRITION, Issue 2 2010
Y.C. YUAN
Abstract A growth experiment was conducted to investigate effect of dietary protein to energy ratios on growth and body composition of juvenile Myxocyprinus asiaticus (initial mean weight: 10.04 ± 0.53 g, mean ± SD). Nine practical diets were formulated to contain three protein levels (340, 390 and 440 g kg,1), each with three lipid levels (60, 100 and 140 g kg,1), in order to produce a range of P/E ratios (from 22.4 to 32.8 mg protein kJ,1). Each diet was randomly assigned to triplicate groups of 20 fish in 400-L indoors flow-through circular fibre glass tanks provided with sand-filtered aerated freshwater. The results showed that the growth was significantly affected by dietary P/E ratio (P < 0.05). Fish fed the diets with 440 g kg,1 protein (100 and 140 g kg,1 lipid, P/E ratio of 31.43 and 29.22 mg protein kJ,1) had the highest specific growth rates (SGR) (2.16 and 2.27% day,1, respectively). However, fish fed the diet with 390 g kg,1 protein and 140 g kg,1 lipid showed comparable growth (2.01% day,1), and had higher protein efficiency ratio (PER), protein productive value (PPV) and energy retention (ER) than other groups (P < 0.05). No significant differences in survival were found among dietary treatments. Carcass lipid content was positively correlated with dietary lipid level, but irrespective of protein level and inversely correlated with carcass moisture content. Carcass protein contents increased with increasing dietary lipid at each protein level. The white muscle and liver composition showed that lipid increased with increasing dietary lipid level (P < 0.05). Dietary protein concentrations had significant effect on condition factor (CF), hepatosomatic index (HSI) and viscerosomatic index (VSI) (P < 0.05). However, dietary lipid concentrations had no significant effect on CF, HSI (P > 0.05). Based on these observations, 440 g kg,1 protein with lipid from 100 to 140 g kg,1 (P/E ratio of 29.22 to 31.43 mg protein kJ,1) seemed to meet minimum requirement for optimal growth and feed utilization, and lipid could cause protein-sparing effect in diets for juvenile Chinese sucker. [source]


The potential of land animal protein ingredients to replace fish meal in diets for cuneate drum, Nibea miichthioides, is affected by dietary protein level

AQUACULTURE NUTRITION, Issue 1 2010
Y. WANG
Abstract A net pen experiment was carried out to examine the effect of dietary protein level on the potential of land animal protein ingredients as fish meal substitutes in practical diets for cuneate drum Nibea miichthioides. Two isocaloric basal (control) diets were formulated to contain 400 g kg,1 herring meal but two different digestible protein (DP) levels (400 versus 350 g kg,1). At each DP level, dietary fish meal level was reduced from 400 to 280, 200, 80 and 0 g kg,1 by incorporating a blend that comprised of 600 g kg,1 poultry by-products meal (PBM), 200 g kg,1 meat and bone meal (MBM), 100 g kg,1 feather meal (FEM) and 100 g kg,1 blood meal (BLM). Cuneate drum fingerling (initial weight 42 g fish,1) were fed the test diets for 8 weeks. Fish fed the test diets exhibited similar feed intake. Final body weight, feed conversion ratio and nitrogen retention efficiency was not significantly different between fish fed the basal diets containing 350 and 400 g kg,1 DP. Weight gain decreased linearly with the reduction of dietary fish meal level at the 350 g kg,1 DP level, but did not decrease with the reduction of dietary fish meal level at the 400 g kg,1 DP level. Results of the present study suggest that fish meal in cuneate drum diets can be completely replaced with the blend of PBM, MBM, FEM and BLM at the 400 g kg,1 DP level, based on a mechanism that excessive dietary protein compensate lower contents of bio-available essential amino acid in the land animal protein ingredients relative to fish meal. [source]


Complete replacement of fish meal by porcine and poultry by-product meals in practical diets for fingerling Nile tilapia Oreochromis niloticus: digestibility and growth performance

AQUACULTURE NUTRITION, Issue 1 2010
C. HERNÁNDEZ
Abstract The apparent digestibility coefficients (ADC) of poultry by-product meal-pet food grade (PBM) and porcine meal (PM) were determined for fingerling male Nile tilapia. ADC for protein were 98.1% and 92.3% in PBM and PM, and 87.1% and 79.4% for energy. PBM and PM were then used as complete replacements for fish meal (FM) in practical diets for Nile tilapia formulated to contain equal digestible protein (300 g kg,1) and energy (16.74 MJ per 100 g) on an as-fed basis. Fingerlings (mean initial weight ±SD, 9.5 ± 0.015 g) were fed for 8 weeks on one of the four diets: FM-, PBM- or PM-based and a commercial feed. The ADC for protein in control and PBM diets (89.7% and 87.9%) were significantly higher than those for the control diet (81.96%). Growth performance and feed utilization were statistically similar between fish fed control and PBM diets, whereas the PM diet exhibited significantly lower performance compared with the control. However, the PM diet showed similar results to the commercial reference diet. Survival and feed conversion ratio were not significantly influenced by replacement of FM with either PBM or PM. The results indicated that PBM and PM can effectively replace FM in practical diets for fingerling Nile tilapia. [source]


Evaluation of practical diets containing different protein levels on gonad development of female redclaw crayfish Cherax quadricarinatus

AQUACULTURE NUTRITION, Issue 4 2009
H. RODRÍGUEZ-GONZÁLEZ
Abstract The effect of five experimental diets with different crude protein content (220, 270, 330, 390 and 450 g kg,1) on gonad development of female Cherax quadricarinatus was tested under laboratory conditions. After 70 days, a significant linear relationship indicated that higher concentrations of protein and carbohydrates in the hepatopancreas were produced as the dietary crude protein increased (P < 0.05). There were significant responses of the gonadosomatic index, hepatosomatic index, biochemical composition of the gonad (protein, lipids, carbohydrates and energy) and frequency of secondary vitellogenic oocytes to dietary protein level, as indicated by significant fits of the quadratic equation to the observed experimental data. The optimal response of the criteria parameters corresponded to levels of crude protein in the range 284,355 g kg,1. Overall, 330 g kg,1 crude protein with a protein : energy ratio of 15.6 mg kJ,1 was considered the most adequate concentration of dietary protein for gonad development and biochemical composition in female redclaw crayfish. [source]


Nutritional evaluation of waste date fruit as partial substitute for soybean meal in practical diets of juvenile Nile tilapia, Oreochromis niloticus L.

AQUACULTURE NUTRITION, Issue 3 2009
M.S. AZAZA
Abstract The potential of waste date meal (WDM; low-quality date palm, Phoenix dactylifera L.) as a carbohydrate source in formulated diets for Nile tilapia was evaluated. Four isocaloric-practical diets (15.7 kJ g,1) were formulated incorporating WDM at 0, 100, 200 and 300 g kg,1 levels as partial substitutes for soybean meal (SBM). These were designated D0 [284 g crude protein (CP) and 383 g carbohydrate (CHO) kg,1 diet], D1 (279 g CP and 446 g CHO kg,1 diet), D2 (207 g CP and 495 g CHO kg,1 diet) and D3 (175 g CP and 578 g CHO kg,1 diet). Each diet was fed to three replicate groups of 30 fish [20.20 ± 0.09 g (±SE)] for 75 days. No feed-related mortality was observed during the entire experimental period. Final body weight (FBW) and specific growth rate (SGR) in the different treatments were statistically not significantly different (P > 0.05). Protein efficiency rate (PER) was lowest in diet D0 and increased with decrease of SBM content (D1,D3). A significant increase in whole body lipid content was recorded in fish fed diets D2 and D3. Results showed that WDM could be a substitute for SBM up to 300 g kg,1 in practical Nile tilapia diets without compromising growth. [source]


Nutritional value of feed peas (Pisum sativum) in practical diet formulations for Litopenaeus vannamei

AQUACULTURE NUTRITION, Issue 2 2002
D.A. DAVIS
Dry peas of mixed Canadian prairie varieties which were commercially obtained and processed to provide a variety of meals were evaluated in practical shrimp feeds. Whole and de-hulled peas were pin milled to produce raw flours. A portion of these meals were processed to produce whole extruded and de-hulled extruded meals. Additionally, a portion of the whole pea meal was processed by infrared cooking to produce a micronized meal. The five meals were evaluated in practical diets for Litopenaeus vannamei under controlled laboratory conditions. The first experiment was designed to estimate apparent protein and energy availability of the various meals. Using a practical reference diet, the meals were substituted using a 70:30 ratio to produce the test diets. Based on contrasts, both extruding and micronizing the pea meals resulted in significant improvements in both apparent protein digestibility and apparent energy digestibility values. Apparent energy digestibility values for the various ingredients expressed as percentage ± SD were: whole raw, 72.3 ± 8.1; whole extruded, 86.0 ± 8.9; de-hulled raw, 88.4 ± 4.4; de-hulled extruded, 94.4 ± 10.0; whole micronized, 94.1 ± 10.2. To evaluate the response of shrimp to the diets containing pea meal, two 7-week growth trials were conducted in the laboratory using a practical diet formulated to contain 360 g kg,1 protein and 90 g kg,1 lipid. In the first growth trial the shrimp had a mean initial weight of 0.66 g and six test diets were evaluated that included the basal diet and five diets for which the pea meals were included in the diet at 250 g kg,1 dry weight replacing whole wheat. In the second growth trial the shrimp had a mean initial weight of 1.1 g and only the whole raw and whole extruded meals were evaluated at 50, 100 and 200 g kg,1 inclusion in the diet. At the conclusion of the first growth trial weight gain ranged from 718 to 862% and at the conclusion of the second growth trial weight gain ranged from 394 to 502%, with no significant differences or discernible trends observed as a result of the various dietary treatments. Based on the observed results, the continued evaluation of feed peas as a potential ingredient of shrimp feeds is warranted. Additionally, if feed peas are suitably priced, commercial producers are encouraged to evaluate feed peas as an alternative protein and energy source. [source]


Partial substitution of fish meal with soybean and cottonseed meals in diets for African bonytongue, Heterotis niloticus (Cuvier, 1829) fingerlings: effects on growth, feed efficiency and body composition

AQUACULTURE RESEARCH, Issue 10 2010
Serge-Eric Monentcham
Abstract A feeding trial was conducted to examine the suitability of soybean meal (SBM) and cottonseed meal (CSM) as a partial substitute for the dietary protein supplied by fish meal for H. niloticus fingerlings. Fish were fed with four isonitrogenous (350 g kg,1 crude protein) and isoenergetic (18.8 kJ g,1 GE) diets in which fish meal protein was gradually replaced by plant protein from a mixture of SBM and CSM (0%, 25%, 50% and 75% in diets 1, 2, 3 and 4 respectively). Triplicate groups of fingerlings H. niloticus (mean weight of 5 g) were handfed twice daily to apparent satiation for 60 days inside net hapas. Growth performances (SGR varied from 3.09% to 3.16% day,1) of fingerlings fed diets containing 0%, 25% and 50% plant protein were not significantly different (P>0.05). At 75% fish meal substitution, growth and feed utilization efficiency indicators were significantly reduced (P<0.05). The carcass composition were also significantly (P<0.05) affected by the replacement level of fish meal, except dry matter and ash. Results suggest that the dietary fish meal protein could efficiently be substituted by a mixture of soybean and cottonseed meals up to 50%, without adverse effects on maximal growth in practical diets for H. niloticus fingerlings. [source]


Apparent digestibility of selected feed ingredients in diets for juvenile hybrid tilapia, Oreochromis niloticus×Oreochromis aureus

AQUACULTURE RESEARCH, Issue 9 2010
Xiao-Hui Dong
Abstract The apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, ash, phosphorus, gross energy and amino acids of 10 selected ingredients for juvenile hybrid tilapia (7.05 ± 0.09 g) were determined using 0.5% Cr2O3 as an inert indicator. The feed ingredients tested in this study were corn gluten meal (CGM), corn byproduct, corn germ meal (CG), soybean meal (SBM), fermented soybean meal (FSM), soy protein concentrate (SPC), soy protein isolate, malt sprouts (MS), fish meal (FM) and earthworm meal (EM). The test diets were prepared by incorporation of 30% test ingredients into the reference diet. Reference and test diets were fed to the fish and the faecal samples were collected using a faecal collection column attached to the fish-rearing tanks. The ADCs for dry matter, crude protein, crude lipid, ash, phosphorus and gross energy were 41.7,98.9%, 90.6,99.6%, 73.1,98.8%, 34.1,98.6%, 49.5,99.6% and 45.4,99.7% respectively. Soy protein isolate, FM and EM had higher dry matter, crude protein and gross energy ADCs. Corn byproduct and EM had higher crude lipid ADCs, and CG and EM had higher phosphorus ADCs. Corn germ meal had the highest ash ADC, while CGM had the highest value for gross energy. The lowest dry matter, crude protein, lipid and gross energy ADCs occurred in MS, while the lowest ash and phosphorus ADCs occurred in SPC. The amino acid ADCs ranged from 83.3% to 100%, exhibiting a positive correlation with crude protein digestibility for a given test ingredient. The feed ingredient digestibility of this study may provide useful information about nutrient and energy utilization to facilitate formulation of least-cost practical diets for hybrid tilapia. [source]