Effects of replacing fish meal with corn gluten meal on growth,feed utilization,nitrogen and phosphorus excretion and IGF‐I gene expression of juvenile Pseudobagrus ussuriensis

Seven isonitrogenous and isolipidic diets containing fish meal (FM) protein replaced by corn gluten meal (CGM) protein at 0% (the control, C0), 10% (C10), 20% (C20), 30% (C30), 40% (C40), 50% (C50) and 60% (C60) were fed to juvenile Pseudobagrus ussuriensis for 8‐weeks to evaluate the effects of FM protein replaced by CGM protein on growth, feed utilization, nitrogen (N) and phosphorus (P) excretion and IGF‐I gene expression of juvenile P. ussuriensis. The results showed that the replacement level up to 40% did not affect the weight gain, specific growth rate (SGR), feed intake and protein efficiency ratio, whereas these parameters were depressed by further replacement level. Apparent digestibility coefficients (ADC) of dry matter, crude protein significantly decreased, but ADC of phosphorus significantly increased with increasing dietary CGM levels (p < .05). Fish fed diets with FM protein replaced by CGM protein led to an increase in nitrogen excretion, but led to a reduction in phosphorus excretion. No significant differences were observed in alpha‐amylase and lipase activities of intestine (p > .05). The lowest pepsin activity was found in C60 group. Fish fed diet C40, C50 and C60 had significantly lower serum lysozyme activity compared with fish fed diet C0 (p < .05). The lowest plasma alkaline phosphatase activity and the highest plasma alanine aminotransferase and aspartate aminotransferase activities were observed in C60 group. Fish fed diet C60 had significantly lower hepatic IGF‐I gene expression compared with fish fed diet C10 (p < .05). Broken‐line model analysis based on SGR against the CGM substitution level indicated that the appropriate replacement level was 37.7%.     

Response of juvenile tench (Tinca tinca L.) fed practical diets with different protein contents and substitution levels of fish meal by soybean meal

A basal practical diet for juvenile tench (Tinca tinca) was formulated and elaborated to test several protein contents and substitution possibilities of fish meal (FM) by soybean meal (SBM) in a 90‐day trial with 5‐month‐old juveniles (30.54 mm TL, 0.30 g W). A factorial design included nine feeding treatments: three protein contents (50%, 40% or 30%) and three levels of replacement (0%, 25% or 45%) of FM protein by SBM protein. In addition, a commercial carp feed was used as reference. Final survival ranged from 98.2% to 99.4%. The 50% dietary protein with 0% or 25% replacement and 40% dietary protein with 25% replacement diets enabled higher growth (P < 0.05) and lower FCR (P < 0.05) than the rest of practical diets. Fish fed 50% dietary protein had similar growth than those fed carp feed (63.8% protein). Deformed fish averaged 1% for the practical diets and 87.6% for the carp feed. The basal practical diet has showed to be feasible and levels of 40–50% dietary protein with 25% replacement of FM protein by SBM protein can be recommended for juvenile tench aged 5–8 months.     

Effect of replacing fish meal with soybean meal on growth,feed utilization and nitrogen and phosphorus excretion on rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

The effect of replacing fish meal with soybean meal (SBM) pretreated with phytase on feeds of juvenile rainbow trout was evaluated in a 90-day feeding trial. The rainbow trout (initial body weight, 4.01 ± 0.02 g) were fed five isonitrogenous (crude protein, 44.97%) and isolipidic (crude lipid, 13.42%) feeds. Diets were formulated to contain phytase-pretreated SBM replacing 0, 20, 40, 60 and 80% of fish meal protein, respectively. The results showed that there was no significant difference in weight gain (WG) among fish fed S0, S20, S40 and S60 diets; however, a significant reduction of this variable occurred when 80% of fish meal protein was replaced by phytase-treated SBM (P < 0.05). Similarly, specific growth rate and protein efficiency ratio had a similar trend with WG. Apparent digestibility coefficient (ADC) of protein and lipid in the S80 diet was significantly lower than that of the other diets, and the ADC of phosphorus significantly increased with the increase of dietary phytase-treated SBM level. No significant differences among treatments were detected for moisture, protein, lipid and ash content in whole body and muscle samples. Nitrogen and phosphorus excretion indicated that fish meal replacement by phytase-treated SBM led to an increase in nitrogen excretion, but led to a reduction in total phosphorus excretion. The results of the present study show that 60% of fish meal could be replaced by phytase-treated SBM in diets of juvenile rainbow trout without compromising weight gain or feed efficiency. A quadratic equation according to regression analysis of weight gain against dietary phytase-treated SBM level indicated that the optimal level of dietary phytase-treated SBM replacement for maximum growth was 26.90%.     

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

The effect of replacing fish meal (FM) with meat and bone meal (MBM) in diets for juvenile Pseudobagrus ussuriensis was evaluated in a 90‐day feeding trial. Six isonitrogenous (crude protein, 430 g/kg) and isolipidic (crude lipid, 74 g/kg) diets were formulated to contain MBM to replace FM at 0 (S0), 200 (S20), 400 (S40), 600 (S60), 800 (S80) and 1000 g/kg (S100), respectively. The results showed that there was no significant difference in weight gain (WG) among fish fed S0, S20 and S40 diets. However, a significant reduction in WG occurred when 600, 800 and 1000 g/kg FM protein was replaced by MBM (p < .05). Similar trends were observed in specific growth rate and protein efficiency ratio. Apparent digestibility coefficients (ADC) of protein and dry matter of the diets S80 and S100 were significantly lower than those of the other diets. The ADC of phosphorus significantly reduced with the increase in dietary MBM level. Nitrogen and phosphorus excretion increased with the increasing dietary MBM level. Protease, lipase and amylase activities of the diets S80 and S100 were significantly lower than those of the other diets (p < .05). The results of this study showed that the optimum dietary MBM replacement level was 34.3% according to broken‐line model based on WG against dietary MBM replacement level.     

Substitution of fish meal by soybean meal in diets for juvenile marbled spinefoot,Siganus rivulatus

The present work was performed to assess whether soybean meal (SBM) could replace fish meal (FM) as a source of dietary protein in diets of the marine herbivore Siganus rivulatus. Five iso-nitrogenous (40% protein) and iso-energetic (14 MJ/Kg) diets were prepared with SBM replacing fish meal at 0%, 25%, 50%, 75%, and 100% dietary protein. A 60-day feeding trial was conducted with 240 juvenile S. rivulatus (initial body mass 1.74 ± 0.03 g). Survival, growth, feed, and protein efficiency and hematological parameters were assessed. Growth correlated negatively with increase in dietary SBM. All production parameters measured were negatively affected at all levels of SBM inclusion. There were no effects on total or differential blood counts, hemoglobin, or plasma protein, but hematocrit values were negatively correlated with SBM addition. Results suggest that total replacement of FM by SBM without adding other supplements is not recommended, even for an herbivorous marine fish such as S. rivulatus.     

Evaluation of soybean meal as alternative to fish meal in diet for juvenile Asian red‐tailed catfish (Hemibagrus wyckioides)

A feeding trial was conducted to determine the amount of soybean meal (SBM) that could replace fish meal (FM) without compromising growth and health of Asian red‐tailed catfish (Hemibagrus wyckioides). Five isonitrogenous and isoenergetic diets (S0, S15, S30, S45 and S60) were formulated with SBM to replace 0%, 15%, 30%, 45% and 60% of FM. The replacement level up to 30% improved daily growth coefficient, plasma adenosine monophosphate deaminase (AMPD) and alanine aminotransferase (ALT) activities and IgM content, and hepatic ALT, aspartate aminotransferase (AST) and glutathione reductase activities, whereas these were depressed by a further inclusion. The highest protein efficiency ratio and lowest feed conversion ratio were observed in fish fed the S15 diet. Replacement of FM with SBM generally decreased plasma insulin and insulin‐like growth factor 1 (IGF‐1) contents and hepatic catalase activity, whereas no significant differences were observed among fish fed the S0, S15 and S30 diets. In contrast, replacing FM with SBM generally increased blood urea nitrogen content, and that was higher in fish fed the S60 diet compared to fish fed the S0 diet. The highest growth hormone (GH) and glutamate dehydrogenase (GDH) activities were observed in fish fed the S30 diet. Fish fed the S30 and S45 diets exhibited the highest hepatic AMPD, GDH, IGF‐1 and target of rapamycin mRNA levels and muscle AMPD and GDH mRNA levels, whereas those were lowest in fish fed the S60 diet. These results indicate that under the reported conditions SBM may be included in the diet up to 222 g/kg as a substitute for FM, replacing about 30% of FM protein in juvenile H. wyckioides.     

Effect of replacing soybean meal with canola meal on growth,feed utilization and haematological indices of juvenile hybrid tilapia,Oreochromis niloticus×Oreochromis aureus

An 8‐week feeding trial was conducted to evaluate the effects of replacing soybean meal (SBM) with canola meal (CM) on growth, feed utilization, body composition and haematological indices of juvenile hybrid tilapia (Oreochromis niloticus×Oreochromis aureus). Six isonitrogenous diets containing graded levels of CM (0, 95, 190, 285, 380 and 634 g kg^?1 of diet corresponding to 0%, 15%, 30%, 45%, 60% and 100%, respectively, of protein from SBM) to replace SBM on an equal protein basis were fed to triplicate groups of juvenile fish (initial weight=6.3 g). The results indicated that up to 30% of SBM could be replaced by CM without causing a significant reduction in growth performance. Fish fed with diets in which CM replaced over 45% of SBM had a significantly lower protein efficiency ratio and a significantly higher feed conversion ratio than fish fed with other diets. The apparent digestibility coefficients (ADC) of dry matter, protein and phosphorus were lowest for fish fed the CM100 diet. Significant differences in haemoglobin, haematocrit and white blood cell concentration were found in fish fed diets with different CM levels. It is concluded that up to 19.02% CM can be used to replace 30% of SBM in diets for juvenile hybrid tilapia without compromising growth, feed conversion and protein utilization.     

Partial replacement of soybean meal by sesame meal in diets of juvenile Nile tilapia,Oreochromis niloticus L.

An 8‐week feeding trial was conducted to determine the effects of replacing of soybean meal (SBM) with sesame meal (SM) in the diets of Oreochromis niloticus fingerlings. Seven practical diets (33 g kg^?1 crude protein, 19.2 MJ kg^?1 dry diet) containing substitution levels of 0%, 8%, 16%, 24%, 32%, 40% and 48% SM for SBM protein were formulated and fed to triplicate groups of O. niloticus fingerlings (mean initial weight of 8.74 ± 0.12 g). The fish survival rate, hepatosomatic index, viscerosomatic index and condition factor were not significantly affected by the contents of SM in the diets (P>0.05). The final body weight, weight gain (WG), specific growth ratio, feed conversion ratio and protein efficiency ratio of the fish fed the diet containing 16% SM were similar (P>0.05) to that of the fish fed the control diet. Except lipid, digestible contents of dry matter, crude protein, ash, gross energy and individual amino acids decreased while phosphorous increased with increasing SM levels. No significant differences were observed in whole‐body dry matter, ash and lipid contents among all the treatments (P>0.05); crude protein contents between fish fed the control diet and a diet containing 24% SM were also not affected significantly (P>0.05), and the phosphorus content was not significantly different when the SM level was increased to 32% (P>0.05). No significant negative differences were observed in the liver composition between fish fed the control diet and the diet containing 24% SM. The most efficient diet in terms of cost per unit WG of fish was obtained in 8% SM dietary substitution, while no significant differences were found among the 0%, 8% and 16% levels. It was indicated that SM can be utilized in the juvenile Nile tilapia diet to replace about 16% of SBM protein without causing negative effects on growth performance, body composition, liver composition and feed utilization.     

Partial replacement of fish meal by soybean meal with or without methionine and phytase supplement in diets for juvenile Chinese sucker,Myxocyprinus asiaticus

This study was designed to evaluate the effects of using soybean meal supplemented with or without methionine (M) and graded levels of phytase (P) to replace high‐level (60%) fish meal in the diets for juvenile Chinese sucker. Seven experimental diets (about 430 g kg^?1 crude protein on dry matter basis) were formulated from practical ingredients. The control diet (FM) was formulated to contain 400 g kg^?1 white fish meal (FM), whereas in the other six diets (diets 2–7), soybean meal (SBM) was used to replace 60% fish meal with or without methionine (3 g kg ^?1) and 0,500, 1000, 1500 and 2000 U kg^?1 phytase (designated as SBM, SM, SMP500, SMP1000, SMP1500 and SMP2000, respectively). Results from the feeding trial indicated that SBM without any methionine or phytase supplement replacing about 60% FM significantly affected the growth of fish (P < 0.05). Weight gain of fish fed diet SM was significantly higher than the fish fed diet SBM, but still much lower than fish fed the control diet (P < 0.05). SBM with methionine and phytase supplement significantly improved the growth of fish and apparent digestibility coefficients of phosphorus compared with the groups which fed diet SBM and diet SM (P < 0.05). Weight gain of fish fed SMP1000, SMP1500 and SMP2000 had no significant difference than fish fed control diet. Furthermore, fish fed SMP1500 showed optimum weight gain and ADC of phosphorus between these three groups. This suggested that soybean meal with 3 g kg^?1 methionine and 1500 U kg^?1 phytase supplement could successfully replace 60% fish meal in the diet for juvenile Chinese sucker without affecting growth and enhanced the apparent digestibility coefficient of phosphorus.     

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.     

Replacement of dietary fish meal by soybean meal supplemented with crystalline methionine for Japanese seabass (Lateolabrax japonicus)

Two 8‐week feeding trials were conducted to evaluate soybean meal (SBM) as a fish meal substitute in diets for Japanese seabass, Lateolabrax japonicas. In trial I, a control diet (C) contained 400 g kg^?1 fish meal, and 20%, 40%, 60% and 80% of the fish meal were replaced with SBM, supplied with 3 g kg^?1 DL‐methionine and 2 g kg^?1 L‐lysine (S20, S40, S60 and S80). In trial II, 60% and 80% of the fish meal in diet C were replaced with SBM, supplied with DL‐methionine at 3 g kg^?1 (S60, S80) or 6 to 7 g kg^?1 (RS60, RS80). The feed intake was lower in fish fed diet C than in fish fed diets S20, S40, S60 and S80 (trial I). No significant differences were found in the weight gain, nitrogen retention efficiency and body composition between fish fed diets C, S20, S40 and S60 (trial I), between fish fed diets S60 and RS60 or between fish fed diets S80 and RS80 (trial II). This study indicates that dietary fish meal level for Japanese seabass can be reduced to 160 g kg^?1 by using SBM as a fish meal substitute.     

Improvement of fish meal replacements by soybean meal and soy protein concentrate in golden pompano diet through γ‐ray irradiation

A 5‐week feeding trial was conducted to examine the effect of γ ‐ ray irradiation on the inclusion of soybean meal (SBM) and soy protein concentrate (SPC) in diets of juvenile golden pompano (Trachinotus ovatus). One diet containing 320 g kg^?1 fish meal served as a reference (C), and another four diets were formulated with 75% of the fish meal replaced by SBM (SM), SPC (SC), SBM irradiated with γ ‐ ray at 30 kGy (SM30) or SPC irradiated with γ ‐ ray at 30 kGy (SC30). The weight gain was higher in fish fed diets SM30 and SC30 than in fish fed diets SM and SC, respectively, whereas fish consumed more diet SM30 than diets SM, SC or SC30. No significant differences were found in feed conversion ratio, nitrogen retention efficiency (NRE), phosphorus retention efficiency (PRE), condition factor, hepatosomatic index (HSI), body composition, waste outputs of nitrogen (NWO) and phosphorus (PWO) either between fish fed diets SM and SM30 or between fish fed diets SC and SC30. The weight gain and PWO were higher, but the PRE and the body phosphorus content were lower in fish fed diet C than those in fish fed diets SM30 or SC30. No significant differences were found in the NRE, condition factor, HSI and body composition (i.e. moisture, crude protein, crude lipid and ash) between fish fed diets C and SM30 or between fish fed diets C and SC30. Macromolecular proteins in SBM and SPC were degraded, whereas the contents of peptides with molecular weight <6.5 kDa were increased by γ‐ray irradiation. This study reveals that γ ‐ ray irradiation can improve the performance of SBM and SPC as a fish meal substitute in the golden pompano diet.     

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.     

Using Bacillus subtilis E20‐fermented soybean meal as replacement for fish meal in the diet of orange‐spotted grouper (Epinephelus coioides,Hamilton)

The potential of Bacillus subtilis E20‐fermented soybean meal (FSBM) as a partial alternative component of fish meal (FM) in fed diets of orange‐spotted grouper (Epinephelus coioides) was evaluated in this study. An FM‐based diet and seven diets containing 10%, 20% and 30% and 10%, 20%, 30% and 40% of FM replaced by soybean meal (SBM) and FSBM, respectively, were fed to grouper for 84 days to evaluate possible substitution levels of FM by tracking growth performance, digestive enzyme activity and morphological changes in the liver and distal intestine. No significant differences in survival and muscle composition of grouper were found between controls and treatments. Growth performance and feed efficiency of fish fed diets with FM replaced by FSBM up to 30% were not significantly different from controls, whereas significantly decreased growth performance and feed efficiency occurred with diets containing >20% of SBM. Based on the feed efficiency, the maximum substituted levels of FM by SBM and FSBM in grouper diets were 18.36% and 29.32%, respectively, based on broken‐line analyses. Histopathological changes in the liver and distal intestine, and significantly lower activity levels of digestive enzymes, including pepsin in the stomach and trypsin, chymotrypsin, amylase and lipase in the distal intestine, were found in fish fed a diet containing 30% of FM replaced by SBM. However, these parameters were improved by the substitution of FSBM. It is therefore believed that FSBM has great potential to be used as a protein source in grouper diets in partial replacement of FM.     

Effects of replacing fish meal with soybean meal on growth,body composition and digestive enzyme activities of juvenile Chinese sucker,Myxocyprinus asiaticus

Six isonitrogenous diets (420 g kg^?1 crude protein on dry matter basis) with six levels of soybean meal (SBM) inclusion (0, 112, 225, 336, 449 and 560 g kg^?1) in substitution of fish meal (0%, 20%, 40%, 60%, 80% and 100%) were evaluated in Chinese sucker of 1.81 ± 0.01 g initial weight for 8 weeks. There existed a significant difference (P < 0.001) in fish weight gain, feed conversion ratio, feed intake, protein efficiency ratio and specific growth rate when the replacement level for fish meal protein was increased from 40% to 60%, indicating that up to 40% of fish meal protein could be replaced with SBM protein without causing reduction in growth and protein utilization. Lipid contents in the Chinese sucker body decreased significantly (P < 0.001) as dietary SBM increased. Digestive enzyme activities in the intestine and hepatopancreas of the fish were significantly different (P < 0.001) as the SBM protein replacement level was increased. Results of the present study appear to indicate that 40% FM can be replaced by SBM in practical feeds of Chinese sucker.     

Potential of processed animal protein versus soybean meal to replace fish meal in practical diets for European catfish (Silurus glanis): growth response and liver gene expression

A 9‐week study was conducted to evaluate the potential of processed animal protein (PAP) in comparison with soybean meal (SM) to replace fish meal (FM) in practical diets for European catfish, Silurus glanis, on growth performance, liver transaminase activities and expression of growth‐related genes. Seven isonitrogenous (440 g kg^‐1 crude protein) and isoenergetic (16.70 MJ/kg) practical diets were formulated by replacing 0 (control), 30%, 60% and 100% FM with either SM or PAP. Each diet was randomly assigned to triplicate groups of 25 fish per cages fixed in the pond. Fish fed the diet substituted 100% FM from SM or PAP had lower (p < .05) growth performance, feed efficiency and protein retention compared to control and other groups. The decreased growth performance occurred concomitant with a decline in the expression level of liver GHR/IGF‐I axis genes. The gene expression and activity of liver protein metabolism enzymes also positively correlated with growth performance. Findings of this study indicated that both SM and PAP were equally effective in replacing FM up to 60% in the practical diet of Silurus glanis. Total replacement of FM either with SM or PAP induced negative influences on growth and feed utilization.     

Evaluation of soybean meal in the formulated diets for juvenile Pangasianodon hypophthalmus (Sauvage, 1878)

The influence of soybean meal (SBM) on the growth and feed utilization of juvenile sutchi catfish (Pangasianodon hypophthalmus, Sauvage, 1878) was investigated. Eight isonitrogenous (300 g kg^?1 CP) and isoenergetic (18 MJ kg^?1) diets were formulated incorporating Argentine SBM to replace fish meal at 0, 150, 300, 450, 600, 750, 900 and 1000 g kg^?1 dietary protein. Each diet was fed to three replicate groups of fish with an initial weight 6.0–6.2 g for twelve weeks. Growth performance decreased, and feed utilization was worsened with the increase in SBM inclusion in the diets. Final weight and relative growth rate (RGR) of fish fed control diet (0 SBM) were significantly higher than those fed test diets (P < 0.05). However, there were no significant differences in the final weight and RGR between the fish fed on 15 SBM, 30 SBM, 45 SBM and 60 SBM diets. Specific growth rate of fish fed 0 SBM, 15 SBM, 30 SBM and 45 SBM diets was significantly higher than those fed other diets. Feed conversion ratio of fish fed 0 SBM, 15 SBM, 30 SBM, 45 SBM and 60 SBM diets was significantly lower than those fed other diets (P < 0.05). The dry matter and protein digestibility were lesser in all the diets in comparison with the control diet. Hepatosomatic index and viscerosomatic index increased with increasing SBM in diet. This present trial indicated that fish meal can be replaced by SBM in the diet of juvenile sutchi catfish only up to 45% of fish meal protein without any adverse effect on growth, feed utilization and body composition.     

Effects of dietary inclusion of soybean meal and cholesterol on the growth,cholesterol status and metabolism of the giant grouper (Epinephelus lanceolatus)

The study evaluated effects of cholesterol supplementation in a diet with high soybean meal (SBM) on the growth and cholesterol metabolism of giant grouper (Epinephelus lanceolatus). All‐fish‐meal diet was used as control. The diet including SBM (replaced 50% of the fish meal protein, SBM diet) and the SBM diet supplemented with 10 g/kg cholesterol (SBM + cholesterol) were used as experimental diets. Three diets were each fed to triplicate groups of juvenile grouper (initial body weight: 12.39 ± 0.36 g) in a recirculating aquaculture system for 8 weeks. Grouper fed the control diet showed higher (p < .05) weight gain, feed intake, feed efficiency and protein efficiency ratio than the other two dietary treatments. Hepatic cholesterol concentrations and 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase gene expressions were higher in fish fed the control diet than fish fed the control diet and SBM + cholesterol diet. Hepatic cholesterol 7α‐hydroxylase gene expression was higher in fish fed the SBM + cholesterol diet than that in fish fed the control diet. Results indicate that giant grouper on a diet low in cholesterol can regulate cholesterol synthesis, suggesting that the reduced dietary cholesterol intake in the fish fed diet containing SBM is sufficiently compensated by increased cholesterol synthesis.     

Effect of replacing fish meal with soybean meal on growth, feed utilization and carcass composition of cuneate drum (Nibea miichthioides)

The effect of replacing fish meal with soybean meal (SBM) in practical feeds for cuneate drum was evaluated in an 8-week net pen trial. The cuneate drum fingerlings (initial body weight 29.8 ± 1.3 g fish^− 1) were fed six isonitrogenous and isocaloric feeds containing 39% digestible protein and 16 MJ kg^− 1 digestible energy. The control feed was formulated to contain 40% herring meal, whereas in the other five feeds SBM was included at 11.3, 22.5, 33.8, 45.0 and 56.3% to replace 20, 40, 60, 80 or 100% of the fish meal. There were no significant differences in feed intake between fish fed the control feed and feeds in which SBM replaced 20 to 80% of the fish meal, but fish fed the fish meal free feed had higher feed intake than the other treatments. Weight gain linearly declined with the decrease of fish meal level. Final body weight (FBW) of fish fed the feeds in which SBM replaced 20% of the fish meal did not significantly differ from fish fed the control feed. Replacing 40 to 100% of the fish meal resulted in lower FBW and nitrogen retention efficiency (NRE), and higher feed conversion ratio (FCR) than those of fish fed the control feed. Fish fed the feeds in which SBM replaced 60 to 100% of the fish meal had lower condition factor and hepatosomatic index than those of fish fed the control feed. No significant differences in carcass protein content was found among the treatments, but fish fed the feeds in which SBM replaced 60 to 100% of the fish meal had higher moisture and lower lipid content in carcass than those of fish fed the control feed. Results of the present study appear to indicate that cuneate drum has a limited ability to utilize SBM as a protein source in practical feeds.     

Replacing fish meal with a blend of poultry by‐product meal and feather meal in diets for giant croaker (Nibea japonica)

An 8‐week feeding trial was conducted to evaluate the potential of replacing fish meal with poultry by‐product meal (PBM) and feather meal (FEM) in giant croaker (Nibea japonica) diet. The control diet (C) contained 400 g/kg fish meal, and 20%, 40%, 60% and 80% of the fish meal in diet C was replaced by a blend of PBM and FEM (PBM: FEM = 7:3) in diets B20, B40, B60 and B80, respectively. The weight gain and feed intake of fish fed diet C did not differ from those of fish fed diets B20 and B40 (p > .05), but were higher than those of fish fed diets B60 and B80 (p < .05). Phosphorus retention efficiency was lower in fish fed diets C, B20 and B40 than in fish fed diets R60 and R80 (p < .05). No significant differences were found in feed conversion ratio, nitrogen retention efficiency, condition factor, hepatosomatic index, body composition and nitrogen waste among the treatments (p > .05). Ratio of fish meal consumption to fish production linearly declined with the decrease in dietary fish meal level. This study indicates that dietary fish meal for giant croaker could be reduced to 240 g/kg by inclusion of the blend of PBM and FEM.