Dietary microbial phytase increased the phosphorus digestibility in juvenile Korean rockfish Sebastes schlegeli fed diets containing soybean meal

This study was conducted to evaluate the effects of dietary microbial phytase supplementation on nutrient digestibility, growth performance and body composition in juvenile Korean rockfish fed soybean meal-based diets.Nine experimental diets were formulated to be isonitrogenous and isocaloric to contain 48.6% crude protein (CP) and 15.9 kJ of available energy/g with or without dietary phytase (Natuphos-5000™, BASF, NJ, USA) supplementation. White fish meal (FM) provided 89.1% of the total protein in the basal diet (S₀), in the other eight diets, 30 or 40% FM protein was replaced by soybean meal: 70% FM+30% soybean meal (S₃₀); 70% FM+30% 1000 U phytase pretreated SM (S₃₀PP₁₀₀₀); 70% FM+30% SM+1000 U phytase/kg diet (S₃₀P₁₀₀₀); 70% FM+30% SM+2000 U phytase/kg diet (S₃₀P₂₀₀₀); 60% FM+40% SM (S₄₀); 60% FM+40% 1000 U P_tre SM (S₄₀PP₁₀₀₀); 60% FM+40% SM+1000 U phytase/kg diet (S₄₀P₁₀₀₀); and 60% FM+40% SM+2000 U phytase/kg diet (S₄₀P₂₀₀₀). After 2 weeks of the adaptation, triplicate groups of 20 fish initially averaging 7.25±0.04 g (mean±S.D.) were randomly distributed into the aquarium and were fed one of the experimental diets for 8 weeks.By the end of the 8-week feeding trial, supplementation of phytase significantly improved the apparent digestibility coefficient (ADC) of phosphorus in rockfish diets (P<0.05) containing 30% and 40% soybean meal regardless of the level and method of phytase supplementation. Supplementation of phytase significantly increased the ADC of dry matter in diets containing 30% soybean meal (P<0.05). However, phytase had no influence on growth performance and whole body composition of fish. The pretreatment of soybean meal with 1000 U phytase improved weight gain (WG) when 30% fish meal protein was replaced by soybean meal. Based on the experimental results, we conclude that supplementation of phytase can improve the apparent digestibility coefficient of phosphorus in Korean rockfish.     

Complementary responses between hydrolyzed feather meal,fish meal and soybean meal without amino acid supplementation in Nile tilapia Oreochromis niloticus diets

The purpose of this study was to evaluate hydrolyzed feather meal (HFM) as a substitute for fish meal (FM) or soybean meal (SBM) in Nile tilapia fry diets. Triplicate groups of fish (initial body weight 2.30 g ± 0.01) were fed seven isonitrogenous and isocaloric diets formulated to contain 30 % crude protein and 19.70 kJ g^?1 gross energy for 8 weeks. The control diet (CD) contained 22 % local FM and 30 % SBM, whereas in the other six diets, HFM replaced 33, 66 or 100 % of FM or SBM. The best weight gain (11.46), specific growth rate (3.14) and feed conversion ratio (1.24) of tilapia fry fed SBM_33%, CD, FM_33% and SBM_66% diets were exhibited. Final body weight and protein retention increased in a linear pattern with increasing amino acids in the experimental diets with the exception of leucine and valine. The results indicated that good-quality HFM can successfully replace FM or SBM by up to 33 and 66 %, respectively, in Nile tilapia fry diets without compromising growth and protein utilization. The results also support the benefits of combining different sources of plant and animal proteins in Nile tilapia diets.     

Partial replacement of fish meal by cottonseed meal and soybean meal with iron and phytase supplementation for parrot fish Oplegnathus fasciatus

Two consecutive feeding trials were conducted to determine the optimum dietary level of the cottonseed and soybean meal (CS) for replacement of fish meal (FM) in diets for juvenile and ongrowing parrot fish with or without iron and phytase. In experiment I, juvenile parrot fish (BW: 3.17 g) were fed one of six experimental diets for 12 weeks which were formulated to replace FM protein by equal proportion (1:1, w:w) of CS at 0, 10, 20, 30, 40, or 50% (designated as CS0, CS10, CS20, CS30, CS40, or CS50, respectively). In experiment II, ongrowing parrot fish (BW: 55 g) were fed one of five experimental diets for 9 weeks. The experimental diets were formulated to replace FM protein by CS at 0, 20, or 30% (designated as CS0, CS20, or CS30, respectively) and to include ferrous sulfate (0.1 and 0.2%) and phytase into the CS20 and CS30 diets (CS20 + Fe&P and CS30 +Fe&P, respectively). Results from the two feeding trials indicated that the CS could replace up to 20% FM protein in diets for juvenile parrot fish (3–22 g) and up to 30% in ongrowing (55–120 g) parrot fish. The supplemental effect of iron and phytase was not significant on growth performance. Total or each gossypol enantiomer concentration in the liver increased as the level of dietary cottonseed meal increased. However, gossypol in the liver of fish fed diets supplemented with iron was not detected. The dietary supplementation of CS significantly reduced the levels of plasma triacyglycerols and total cholesterol. The present study indicates that plant protein sources are better utilized in larger fish, and that up to approximately 30% FM protein could be replaced by CS with iron and phytase in the presence of supplemental lysine and methionine.     

Supplemental iron and phosphorus increase dietary inclusion of cottonseed and soybean meal in olive flounder (Paralichthys olivaceus)

A long‐term feeding experiment was conducted to investigate the use of cottonseed and soybean meal (CS) with iron and phosphorus supplements in diets for olive flounder (Paralichthys olivaceus). Olive flounder with an initial average size of 28.5 ± 0.35 g (mean ± SD) were divided into 15 groups (three tanks per dietary treatment) and fed 480 g kg^?1 crude protein diets in which each of five isonitrogenous diets was formulated to contain different levels of cottonseed/soybean meal (1 : 1) to replace fish meal (FM) with iron and phosphorus supplementations. The five experimental diets were as follows: diet 1 (control), 0%CS; diet 2, 20%CS; diet 3, 30%CS; diet 4, 30%CS + Fe&P; and diet 5, 40%CS + Fe&P. After 26 weeks of feeding trial, no significant differences were observed in weight gain, feed utilization and survival among all the treatments. The total gossypol accumulation in liver of fish fed diets supplemented with iron was significantly lower than that of fish fed diets without supplementation of iron. The results indicate that the addition of iron in diets could prevent the absorption of free gossypol. The findings in this study suggest that dietary supplements of iron and phosphorus could increase the inclusion of cottonseed and soybean meal for FM replacement in diets for marine fish species.     

Partial substitution of dietary fish meal with soybean meal for speckled shrimp,Metapenaeus monoceros (Fabricius, 1798) (Decapoda: Penaeidae) juvenile

A 63‐day feeding study was conducted to evaluate the effect of partial substitution (0%, 20%, 40% and 60%) of dietary fish meal (FM) with soybean meal (SBM) on the growth performance and feed utilization of speckled shrimp, Metapenaeus monoceros juveniles. A total of 180 M. monoceros juveniles with an average weight of 0.67 ± 0.18 g were equally distributed over 12 glass aquaria (30 L each, triplicate per treatment). All aquaria were filled with filtered sea water (30–35 ‰, salinity). Four isonitrogenous (400 g kg^?1 crude protein) and isocaloric (20.5 MJ GE kg^?1) test diets were formulated. The control diet contained FM (D₁) as the main protein source. In the other diets, FM was partially replaced with 20 (D₂), 40% (D₃) or 60% (D₄) SBM. The results indicate that the diet in which 40% of the FM is replaced by SBM yields similar growth and production, and is as cost effective, as the control diet.     

Substituting fish meal with poultry by-product meal in diets for black Sea turbot Psetta maeotica

A 60 days feeding experiment was carried out with Black Sea turbot Psetta maeotica to determine the amount of poultry by‐product meal (PBM) that could replace fish meal (FM) in formulated diets without reducing growth performance. Juvenile Black Sea turbot (initial average weight, 30 g) were fed five isoenergetic (gross energy, 20.5 ± 0.21 kJ g^?1 diet) and isonitrogenous diets (protein content, 550 ± 0.35 g kg^?1). The control diet used white FM as the sole protein source, the other four diets were prepared to replace FM protein at levels of 25%, 50%, 75% and 100% with PBM. The fish readily accepted all experimental diets and no mortality were recorded during the trial. There were no significant differences in growth performance of turbot (P < 0.05) fed the diets with 25% and 50% replacement levels compared with fish offered the control diet (100% FM), however, final body weight and specific growth rate values in the 50% replacement diet were about 8% lower than those of the control. Total nitrogen excretion in fish fed 50% replacement diet were about 10% higher than the control group, even though these parameters were not found to be statistically different. At the levels of 750 and 1000 g kg^?1 of the protein, PBM inclusion caused a severe decrease in growth performance, feed utilization, protein efficiency ratio and per cent nitrogen retention. The results in the present study indicate that up to 25% of FM protein can be replaced by PBM protein without causing reduction in growth performance, nutrient utilization and nitrogen retention.     

Bio‐Ag reutilization of distiller's dried grains with solubles (DDGS) as a substrate for black soldier fly larvae,Hermetia illucens,along with poultry by‐product meal and soybean meal,as total replacement of fish meal in diets for Nile tilapia,Oreochromis niloticus

A feeding trial was conducted in a closed system with Nile tilapia, Oreochromis niloticus, juveniles (mean initial weight, 2.66 g) to examine total replacement of menhaden fish meal (FM) with distiller's dried grains with solubles (DDGS), which had been used as substrate for the production of black soldier fly larvae, Hermetia illucens, in combination with soybean meal (SBM) and poultry by‐product meal (PBM), with or without supplementation of the amino acids (AA) DL‐methionine (Met), L‐lysine (Lys) and a commercial non‐amylaceous polysaccharide enzyme (Enz) product. Fish were fed seven isoenergetic [available energy (AE) = 4.0 kcal g^?1 of diet] and isonitrogenous (350 g kg^?1 protein as‐fed basis) practical diets formulated with equivalent digestible protein levels. Diet 1 was formulated to be similar to a commercial, high‐quality, tilapia diet containing 200 g kg^?1 FM. Diets 2–5 were formulated as a 2 × 2 factorial to replace FM with similar contributions from DDGS (45%), PBM (25%) and SBM (2.1–2.9%), but to differ in supplementation of AA and/or Enz preparation. Diets 6 and 7 were formulated to investigate the effects of a 2/3 and 1/3 reduction, respectively, in DDGS contribution to the replacement protein mix, with concomitant increases in SBM, with respect to diet 3, and were balanced with Lys and Met. After 6 weeks, growth responses were slightly attenuated (P ≤ 0.05) and average daily intake (ADI) and feed conversion ratio (FCR) were slightly higher in tilapia fed DDGS diets 2–5 compared to those of fish fed the FM control diet 1. Growth responses were not significantly affected by the presence or absence of AA or Enz (diets 2–5), or the level of DDGS (diets 3, 7 and 6). Whole‐body proximate composition was not different among treatments. Amino acid profiles of fish fed DDGS diets were not significantly different from those of fish fed the FM control. Evidence of interaction between AA and Enz supplementation was detected in whole‐body amino acid concentrations such that AA content was higher with AA or Enz addition alone, but lower when both were added to the diet. Results suggest that DDGS replacement of FM in tilapia diets can be substantial when diets are formulated on a digestible protein basis and DDGS is combined with highly digestible animal (PBM) and plant proteins (SBM).     

Effects of replacing fish meal with soybean meal and peanut meal on growth,feed utilization and haemolymph indexes for juvenile white shrimp Litopenaeus vannamei,Boone

An 8‐week feeding trial was conducted to evaluate the effects of replacing fish meal (FM) with soybean meal (SBM) and peanut meal (PM) on growth, feed utilization, body composition and haemolymph indexes of juvenile white shrimp Litopenaeus vannamei, Boone. Five diets were formulated: a control diet (FM30) containing 30% fish meal and four other diets (FM20, FM15, FM10 and FM5) in which protein from fish meal was substituted by protein from SBM and PM. The dietary amino acids of diets FM20, FM15, FM10 and FM5 were equal to those of the diet FM30 by adding crystalline amino acids (lysine and methionine). Each diet was randomly assigned to triplicate groups of 30 shrimps (initial weight = 0.48 g), each three times daily. The results indicated that shrimp fed the diets FM15, FM10 and FM5 had poor growth performance and feed utilization compared with shrimp fed the control diet. No difference was observed in feed intake, survival and body composition among dietary treatments. The plasma total cholesterol level of shrimp and the digestibility of dry matter, protein and energy contained in the diets decreased significantly with increasing PM and SBM inclusion levels. Results of this study suggested that fish meal can be reduced from 300 to 200 g kg^?1 when replaced by a mixture of SBM and PM.     

Effects of the different levels of dietary vitamin C on growth and tissue ascorbic acid changes in parrot fish (Oplegnathus fasciatus)

An 11-week feeding trial was conducted to study the effects of the different levels of dietary vitamin C on growth, tissue ascorbic acid concentrations and histopathological changes in parrot fish. Casein and gelatin-based diets were formulated to contain 0, 60, 120, 240, 480 and 2000 mg l-ascorbic acid (AA) per kg diets on AA equivalent basis in the form of l-ascorbyl-2-monophosphate (AMP), 60 and 240 mg AA per kg diet as l-ascorbic acid. However, the analyzed AA levels were 0, 50, 100, 205, 426 and 1869 mg AA per kg diet in AMP supplemented diets; 36 and 149 mg AA per kg diet in l-ascorbic acid supplemented diets. Thus, the diets were designated as AA-free, AMP₅₀, AMP₁₀₀, AMP₂₀₅, AMP₄₂₆, AMP₁₈₆₉, AA₃₆ and AA₁₄₉. Fish averaging 3.9±0.06 g (mean±S.D.) randomly were fed the experimental diets in triplicate groups for 11 weeks. Weight gain (WG) of fish fed AMP₅₀ and AA₃₆ diets were significantly lower than those of the other groups, and fish fed AMP₁₈₆₉ diet showed a higher WG than did fish fed AMP₅₀, AMP₁₀₀, AMP₂₀₅, AA₃₆ and AA₁₄₉ diets (P<0.05). However, there was no significant difference in WG between fish fed diets AMP₄₂₆ and AMP₁₈₆₉, and among fish fed AMP₁₀₀, AMP₂₀₅, AMP₄₂₆ and AA₁₄₉ diets. Fish fed the AA-free diet began to show deficiency signs, such as retarded growth, darkening, anorexia and high mortality, after 3 weeks of feeding trial. After 6 weeks of the feeding trial, liver from fish fed the AA-free diet showed severe atrophy. By the end of the seventh week, all fish fed the AA-free diet were dead. Liver AA concentration from fish fed AMP₅₀ diet was significantly lower than that from fish fed AMP₂₀₅, AMP₄₂₆, AMP₁₈₆₉ and AA₁₄₉ diets, and fish fed AMP₅₀, AMP₁₀₀, AA₃₆ diets showed a significant lower AA concentration in liver than did fish fed AMP₂₀₅, AMP₄₂₆ and AMP₁₈₆₉ diets.Broken line analysis of weight gain indicated that the dietary vitamin C requirement of parrot fish is 118±12 mg AA per kg diet in the form of l-ascorbyl-2-monophosphate for maximum growth.     

Effect of fish meal replacement by Chlorella meal with dietary cellulase addition on growth performance,digestive enzymatic activities,histology and myogenic genes’ expression for crucian carp Carassius auratus

This study was conducted to investigate the effects of fish meal (FM) replacement by Chlorella meal (CM) with dietary cellulase supplementation on growth performance, digestive enzymatic activities, histology and myogenic genes’ expression in crucian carp Carassius auratus (initial body weight: 2.90 ± 0.02 g, mean ± SEM). Six isonitrogenous diets were formulated at two cellulase levels (0 and 2 g kg^?1). At each cellulase level, CM was added at three levels of 0, 533.1 and 710.8 g kg^?1 to substitute 0, 75 and 100% of dietary FM respectively. Each experimental diet was randomly assigned to triplicate groups with 25 juvenile fish per fibreglass tank for 8 weeks. Dietary CM substitution significantly increased growth, feed utilization, amylase activity and the expression of Myod, Mrf4 and Myf5, but reduced the Myog expression. Dietary cellulase addition increased hepatosomatic and viscerosomatic index, lipase activity and the expression of Mrf4, but reduced trypsin activity and the expression of Myog and Myf5. Dietary CM substitution enlarged the cell size and also caused some karyopyknosis in liver. Our results showed that CM could totally replace FM in diets; dietary cellulase supplementation at the level of 2 g kg^?1 played a subtle role in improving growth and feed utilization for crucian carp.     

Partial replacement of fish meal by a mixture of soybean meal and rapeseed meal in practical diets for juvenile Chinese mitten crab Eriocheir sinensis: effects on growth performance and in vivo digestibility

An 8‐week experiment was conducted to examine the effect of partial replacement of fish meal (FM) by a mixture of soybean meal (SBM) and rapeseed meal (RM) in practical diets of juvenile Chinese mitten crab Eriocheir sinensis of initial body weight of 1.54±0.12 g (means±SD, n=90). Five isonitrogenous diets were formulated to contain 35% protein and 5% lipid. Soybean meal and RM mix (1:1 ratio) were included at five levels of 0 (control), 15%, 30%, 45% and 60%, replacing 0, 20%, 40%, 60% and 80% FM respectively. When FM was replaced by 15% of SBM and RM, crab showed the highest growth, feed utilization and moulting frequency (MF). Fish meal replaced by SBM and RM did not significantly influence crude protein, lipid and moisture contents of whole body crab, but ash content was the lowest for crab fed the diet with FM replaced by 15% of SBM and RM. Apparent digestibility coefficients (ADCs) of dry matter, crude protein and energy tended to decline with increasing inclusion levels of dietary SBM and RM. In general, ADCs of lipid were high (over 90%) and showed no significant differences among the treatments (P>0.05). Based on these observations above, these results indicated that about 40% of FM can be replaced with a mixture of SBM and RM (1:1 ratio) in the diet of E. sinensis without adverse growth performance, compared with the FM‐based diet. However, 20% of FM replaced by SBM and RM produced the best growth performance and feed utilization.     

Partial replacement of fish meal by several plant proteins with or without iron and lysine supplement in diets for juvenile Chinese sucker,Myxocyprinus asiaticus

Two feeding experiments were conducted to evaluate the potential of fermented soybean meal (FSBM), corn gluten meal (CGM) and cottonseed meal (CSM) with or without lysine (L) and iron (Fe) to replace fish meal (FM) in practical diets of juvenile Chinese sucker. In experiment I, four experimental diets (430 g kg^?1 crude protein on dry matter basis) were formulated. Diet containing FM as the main protein source was used as a control (Diet 1). Diets 2–4 had 300 g kg^?1 FM protein replaced with FSBM, CGM or CSM protein without iron or lysine supplement. Fish (average weight, 1.82 ± 0.01 g) were hand‐fed twice daily for 8 weeks. In experiment II, juvenile Chinese sucker (average weight, 3.40 ± 0.08 g) were fed one of five experimental diets twice daily for 8 weeks. Diet 1 in experiment I was used as a control and Diet 4 in experiment I, with ferrous sulphate, with lysine or with both ferrous sulphate and lysine were used as the experimental diets (designated as FM, CSM, CSM+Fe, CSM+L and CSM+Fe&L, respectively). Results from the two feeding trials indicated that about 300 g kg^?1 of FM protein can be replaced by FSBM, CGM or CSM with lysine supplement in Chinese sucker diets without adversely affecting growth. CSM with iron could not improve the growth performance. CSM without lysine supplement significantly affected the growth performance, body composition and digestive enzyme activities.     

The use of tuna industry waste in the practical diets of juvenile Nile tilapia (Oreochromis niloticus,L.): effect on growth performance,nutrient digestibility and oxidative status

A 45‐day feeding trial was conducted to study the effect of replacing dietary fish meal (FM) with a tuna by‐product meal (TBM) on the growth, feed efficiency, carcass composition and stress oxidative status of juvenile Nile tilapia, Oreochromis niloticus L.). Triplicate groups of fish (2.21 ± 0.01 g) were fed on four iso‐nitrogenous and iso‐energetic diets. The control diet (A₀) used FM as the sole source of animal protein. In the other three diets (A₁₀–A₃₀), 33%–100% of FM was substituted by TBM at 10% increments. There were no significant differences (P>0.05) in growth performance among fish fed on diets A₀, A₁₀ and A₂₀. Fish fed these experimental diets (i.e., A₀, A₁₀ and A₂₀) showed significantly (P<0.05) better daily mass gain, specific growth rate and protein efficiency ratio than those fed on diet A₃₀. Feed conversion ratio increased with increasing TBM content, but only the value found in fish fed on diet A₃₀ differed significantly (P<0.05) from the other treatments. The fish accumulated increasing quantities of lipids and decreasing levels of ash in their carcasses with increasing levels of dietary TBM. At the end of the experimental period, a significant increase (P<0.001) in catalase and glutathione S‐transferase activities was seen only in groups fed on diet A₃₀. Similarly, a significant enhancement in glutathione peroxidase and superoxide dismutase activities was observed in groups fed on diets A₂₀ and A₃₀ compared with the other groups. The results show that this product can be included up to 20% in practical Nile tilapia diets without any detrimental effects.     

Effect of replacing fish meal with soybean meal on growth,feed utilization and nitrogen and phosphorus excretion of juvenile Pseudobagrus ussuriensis

An 8‐week feeding trial was conducted to evaluate the effects of replacing fish meal with soybean meal (SBM) on growth, feed utilization, and nitrogen (N) and phosphorus (P) excretion of juvenile Pseudobagrus ussuriensis (initial average weight 0.50 ± 0.00 g). Seven isonitrogenous and isolipidic diets were formulated to contain SBM to replace fish meal protein at 0% (S0), 10% (S10), 20% (S20), 30% (S30), 40% (S40), 50% (S50) and 60% (S60) respectively. To investigate the effects of supplementation with crystalline amino acid to balance diet S60, one diet was formulated to add 0.30% methionine (SM60). The results showed that there was no significant difference in weight gain among fish fed S0, S10, S20, S30 and S40 diets, however, a significant reduction in this variable occurred when 50% and 60% of fish meal protein was replaced by SBM (P < 0.05). Apparent digestibility coefficients of dry matter, crude protein and phosphorus of diets were affected by dietary SBM levels. N and P excretion indicate that fish meal replacement by SBM led to an increase in N excretion, but led to a reduction in P excretion. No differences were detected in growth, feed utilization and N and P excretion between fish feed diets S60 and SM60. The results of this study show that 40% of fish meal protein could be replaced by SBM in diets of juvenile P. ussuriensis without having a significant negative effect on growth or feed efficiency, but that higher dietary SBM levels reduce fish performance.     

Replacement of fish meal with poultry by-product meal in practical diets for redclaw crayfish (Cherax quadricarinatus)

Aquaculture of redclaw crayfish, Cherax quadricarinatus, is rapidly developing in tropical and sub‐tropical regions of the world. As the industry is still in its infancy, grow out diets are generally not formulated specifically for this species as there is limited data on nutrient requirements and the acceptability of various ingredients. Given the recent increases in the price of fish meal (FM), the use of alternative protein sources such as poultry by‐product meal (PBM) may be more cost effective. The present research evaluated the response of juvenile redclaw to practical diets utilizing PBM as a replacement for FM. Juvenile redclaw crayfish (0.45 g ± 0.01) were stocked into 24, 600‐L, outdoor round tanks at a density of 12.5 m^?2. Tanks were supplied water from a watershed reservoir and maintained on a flow through regime. Crayfish in four replicate tanks were maintained on one of the six diets formulated to contain 260 g kg^?1 crude protein and 70 g kg^?1 crude fat which had previously demonstrated good growth under similar conditions. FM in the basal diets was replaced with PBM at various levels, on an iso‐nitrogenous basis, so that the diets contained 150, 120, 90, 60, 30 and 0 g FM kg^?1 diet and 78, 105, 132, 158, 185 and 212 g PBM kg^?1 diet, respectively. At the conclusion of the 56‐day growth trial, survival (>83%) and growth (>11.3 g or 2400%) of the crayfish were not significantly different among treatments. Based on these results, PBM appears to be a viable candidate as a replacement for FM in redclaw crayfish diets.     

Evaluation of tuna by‐product meal as a protein source in feeds for juvenile spotted rose snapper Lutjanus guttatus

This study evaluated the use of tuna by‐product meal (TBM), a locally produced feed ingredient, as a replacement for fish meal (FM) in diets for spotted rose snapper, Lutjanus guttatus. Six isonitrogenous compounds [480 kg^?1 crude protein (CP) and isoenergetic diets (21 kJ g^?1)] were formulated to replace 0 (D‐0%), 10 (D‐10%), 20 (D‐20%), 30 (D‐30%), 40 (D‐40% or 50% (D‐50%) of FM protein with TBM protein. Each diet was fed to four replicate groups of spotted rose snapper (initial weight 5.4 g ± 0.04 g) to apparent satiation three times a day. After 8 weeks of feeding, the fish gained 4–5 times their initial weight. Spotted rose snapper fed D‐30% had a significantly higher specific growth rate (2.7% day^?1) than fish fed the other diets containing lower or higher amounts of TBM. Haematological parameters and whole‐body proximate composition were unaffected by diet (P > 0.05). The ADC for protein and energy in D‐0%, D‐20% and D‐30% were significantly higher than those for the D‐40% and D‐50% groups. A broken line model indicated that 262 g kg^?1 TBM in the diet would yield maximum growth of the spotted rose snapper. The results of this study demonstrate that TBM is an acceptable ingredient for replacing 25–30% of dietary protein from FM in spotted rose snapper diets but that higher replacement levels reduce fish performance.     

Using a fermented mixture of soybean meal and earthworm meal to replace fish meal in the diet of white shrimp,Penaeus vannamei (Boone)

An experiment was conducted to evaluate the potential of a Bacillus subtilis E20‐fermented mixture (FSFEM) containing soybean meal (SBM) and Eisenia fetida earthworm meal (EM) at a ratio of 4:1 to increase the methionine level in order to satisfy the methionine requirement of white shrimp, Penaeus vannamei in a diet with fish meal (FM) completely replaced by mixtures. B. subtilis E20 fermentation improved the mixture's palatability and utilization based on better growth performance in comparison to shrimp fed FSEM (contains fermented SBM and EM at a ratio of 4:1) diets. FSFEM is a good substitute for FM. Maximal replacement levels of FM with FSFEM were 80% in a shrimp diet with 37% of crude protein and 7% of crude lipid based on weight gain and 100% based on feeding efficiency. In addition, shrimp fed experimental diets had no significant differences in survival after being challenged by Vibrio alginolyticus. It is suggested that B. subtilis E20‐FSFEM has the potential to replace FM in cultured shrimp diets.     

Effects of spray‐dried blood cell meal with microencapsulated methionine substituting fish meal on the growth,nutrient digestibility and amino acid retention of Litopenaeus vannamei

The effect of substitution of fish meal (FM) by spray‐dried blood cell meal (SBCM) with microencapsulated dl ‐methionine supplementation in trial diets for Litopenaeus vannamei was evaluated. Six isonitrogenous (320 g kg^?1) and isolipidic (85 g kg^?1) diets were formulated to feed shrimp (2.3±0.2 g shrimp^?1) for 56 days. Shrimp were fed with six diets in which FM protein was gradually replaced by SBCM protein (0%, 20%, 40%, 60%, 80% and 100% in diets 0–5). Growth performances and feed utilization of shrimp fed diets containing 0%, 3.5%, 7.0% and 10.5% SBCM protein were not significantly different (P>0.05). Growth, feed conversion ratio and protein efficiency ratio of shrimp fed diets (80 and 100% FM substitution) were significantly poorer compared with other treatments (P<0.05). With increased levels of dietary SBCM, apparent digestibility coefficient of dry matter, crude protein enhanced from 76.9% to 82.3%, 84.8% to 89.0%, but crude lipid decreased from 90.6% to 88.3% respectively. The carcass composition values were not significantly (P>0.05) affected by the replacement level of FM, except lipid. There were no significantly differences (P>0.05) in amino acid retentions among Diets 0–3. The results suggest that the dietary FM protein could efficiently be substituted by SBCM up to 60%, without adverse effects on the growth of L. vannamei.     

Dry whey meal as a protein source in practical diets for Nile tilapia,Oreochromis niloticus fingerlings

ABSTRACT

This study was conducted as a trial of using dry whey meal (DWM) as a substitute for fish meal (FM) in practical diets for Nile tilapia, Oreochromis niloticus. Triplicate fish groups were fed on five isonitrogenous (30.2%) and isolipidic (6.9%) diets. The control diet (D1) used FM as the sole protein source. In the other four diets (D2–D5), FM protein was substituted by 25, 50, 75, or 100% DWM. Fish (3.5 ± 0.1 g) were stocked at a rate of 20 fish per 100-L aquarium and fed one of the tested diets up to satiation twice daily for 12 weeks. Fish growth, feed utilization, protein efficiency ratio, apparent protein utilization, and energy utilization for fish fed DWM diets up to 75% FM (D2–D4) tended to be higher but were not statistically different than the control diet. No significant effect of diet was found in whole-body moisture, crude protein, and total ash contents. Whole-body lipid content in fish fed the 100% DWM (D5) diet was significantly higher than that for fish fed the control diet. The optimal replacement level of FM by DWM was estimated by second-order polynomial regression to be 62.5%.