Effect of dietary replacement of fish meal by soybean protein concentrate on growth performance and phosphorus discharging of juvenile black sea bream,Acanthopagrus schlegelii

The 8‐week experiment was conducted to evaluate the effects of partial replacement of fish meal (FM) with soybean protein concentrate (SPC) on juvenile black sea bream, Acanthopagrus schlegelii (10.70 ± 0.04 g). Diets were formulated to replace FM protein by SPC at 0, 8, 16, 24, 32 or 40% (designated as T1, T2, T3, T4, T5 and T6, respectively). Diets except T1 were supplemented with phytase at 2000 phytase activity U kg^?1. The results showed that survival rate, growth performance and feed utilization were not significantly affected by increasing dietary SPC. Fish fed diet T3 had higher feed intake compared to those fed T1, T2 and T5 diets. Whole body compositions of black sea bream were significantly influenced by SPC replacing FM except for protein, ash and phosphorus content. Condition factor of fish was significantly lower in T2 than that of fish in T3 group. Apparent digestibility coefficients (ADCs) of dry matter was higher in fish fed T6 diet than those of fish fed T1 and T2 diets, ADCs of phosphorus increased with dietary SPC level up to T3 and then decreased. The results obtained in this study indicate that FM protein could be effectively replaced by SPC protein with phytase in diet of black sea bream.     

Effects of replacing fish meal with soya protein concentrate on growth,feed efficiency and digestibility in diets for snakehead,Channa striata

Soya bean meal‐based formulated feeds have recently become available for snakehead culture in Vietnam. This study was conducted to determine the appropriate replacement of fish meal (FM) protein by another soya product, soya protein concentrate (SPC), in snakehead (Channa striata) diets. Five iso‐nitrogenous (45% crude protein) and iso‐caloric (19 KJ g^?1) practical diets were formulated to replace 0% (control), 40%, 60%, 80% and 100% of protein FM by protein SPC (100% FM, 40% SPC, 60% SPC, 80% SPC and 100% SPC respectively). A digestibility experiment was also conducted with the same formulated diets with addition of 1% chromic oxide. Fish fed 100% FM and 40% SPC diets had significantly better growth and survival compared with other treatments. Feed intake, feed conversion ratio, protein efficiency ratio and net protein utilization, trypsin and chymotrypsin activities of experimental fish fed 100% FM and 40% SPC diets were significantly higher than those fed other diets. The apparent digestibility coefficient (ADC) of the diet and diet components, ADC_diet, ADC_protein and ADC_lipid, of fish fed diet 40% SPC and 100% FM treatment were significantly higher than those of other treatments. The cost/kg fish produced in diets 100% FM and 40% SPC was much lower compared with other treatments. Dietary inclusion levels of SPC in diet above 40% significantly affected fish survival, growth, digestibility and trypsin and chymotrypsin activities, although fish chemical composition was not greatly affected.     

Dietary substitution of fishmeal by alternative protein with guanosine monophosphate supplementation influences growth,digestibility, blood chemistry profile,immunity, and stress resistance of red sea bream, <Emphasis Type="Italic">Pagrus major</Emphasis>

We determined the effects of complete fishmeal (FM) replacement by alternative protein (soy protein concentrate, SPC) with guanosine monophosphate (GMP) supplementation on growth, digestibility, immunity, blood chemistry profile, and stress resistance of juvenile red sea bream, Pagrus major. FM protein of a FM-based control diet (FM0) was replaced with 33.3 (FM33.3), 66.6 (FM66.7), and 100% (FM100) by SPC protein, and each replacement group was supplemented with 0.4% GMP to formulate four experimental diets. Each diet was randomly allocated to triplicate groups of fish (4.8 g) for 56 days. Results demonstrated that fish fed diet group FM33.3 had the significantly highest final weight, weight gain-specific growth rate, and feed intake. Meanwhile, in comparison to control, growth performance and feed utilization did not significantly differ with 66.7% FM replacement by SPC with GMP supplementation. Apparent digestibility coefficient of protein and lipid also followed a similar trend. All growth, feed utilization, and digestibility parameters were significantly lower in FM100 diet group. Blood urea nitrogen (BUN) and triglycerides (TG) increased (P < 0.05) with increasing FM replacement level by SPC. Interestingly, total cholesterol level reduces with the increasing level of FM replacement by SPC with GMP supplementation. Fish fed FM0 diet group showed the best condition of both oxidative and freshwater stress resistance. Meanwhile, FM33.3 and FM66.7 diet groups showed acceptable conditions. Innate immune responses enhanced with the increasing FM replacement level by SPC with GMP supplementation. In conclusion, FM could be replaced ≤66.7% by SPC with GMP supplementation in diets for red sea bream without any adverse effects on fish performances.     

Growth,enzymatic glutathione peroxidase activity and biochemical status of juvenile barramundi (<Emphasis Type="Italic">Lates calcarifer</Emphasis>) fed dietary fermented soybean meal and organic selenium

Solvent-extracted soybean meal (SBM) was fermented using baker’s yeast Saccharomyces cerevisae at 30 °C for 5 days. Four isonitrogenous and isocaloric diets containing 75% SBM protein, either fermented or non-fermented (SBM and FSBM), and supplemented or not with organic Se (OS) (SBM_OS and FSBM_OS), were fed to triplicate groups of juvenile barramundi (Lates calcarifer) (initial weight of 5 g) for 75 days. A fishmeal (FM)-based diet formulated for juvenile barramundi was used as a reference diet. The growth of fish was significantly affected by either the interaction of SBM type or by the OS level. In fish fed diets supplemented with OS (SBM_OS and FSBM_OS), final weight (FW), specific growth rate (SGR) and weight gain (WG) were higher in fish fed the fermented SBM (FSBM_OS) than in those fed the non-fermented SBM (SBM_OS). The apparent digestibility coefficient (ADC) of protein was higher in the fish fed the fermented SBM, either supplemented or unsupplemented with OS. However, there were no significant differences in the ADC of dry matter (DM) and lipids among the tested diets and in comparison to the reference diet. The haematocrit and leucocrit of fish fed the FSBM_OS diet were lower than those of fish fed the FM diet. Furthermore, glutathione peroxidase (GPx) activity was significantly influenced by OS supplementation in the experimental diets; GPx activity was greater in the fish fed diets supplemented with OS. Creatinine kinase (CK) of all groups of fish was higher than the CK of those fed the reference diet. These results suggest that with a proper nutritional level, OS supplementation may act as an important factor in enzymatic GPx activity and in the haematology and blood biochemistry status of juvenile barramundi fed fermented SBM-based diets, encouraging improvement of the overall growth performance.     

Partial and total replacement of fishmeal with poultry by-product meal in diets for gibel carp, Carassius auratus gibelio Bloch

Triplicate groups of gibel carp Carassius auratus gibelio Bloch (initial body weight: 4.89 g) were fed for 8 weeks at 24.8–30.8°C with nine isonitrogenous and isoenergetic diets. The control diet (F1) used white fishmeal (FM) as the sole protein source. In the other eight diets (F2–F9), 40.5–100% of FM protein was substituted by poultry by‐product meal (PBM) at 8.5% increments. The specific growth rate (SGR), feed efficiency ratio, protein efficiency ratio, protein retention efficiency and energy retention rate for fish fed PBM diets (F2–F9) were all higher, but not always significantly, than those for fish fed F1. All apparent digestibility coefficients for fish fed PBM diets were lower than those for fish fed F1. Fish fed F1 had a significantly higher hepatosomatic index value than fish fed PBM diets (P<0.05). No significant (P>0.05) effect of diet was found in whole‐body moisture and fat content. Whole‐body protein and energy content for fish fed PBM diets were slightly higher than that for fish fed F1. The optimal replacement level of FM by PBM was estimated by second‐order polynomial regression to be 66.5% in protein.     

Replacement of fishmeal by soya protein concentrate in the diets of Totoaba macdonaldi (Gilbert, 1890) juveniles: effect on the growth performance,in vitro digestibility,digestive enzymes and the haematological and biochemistry parameters

The potential of soya protein concentrate (SPC) as an alternative protein source in diets for Totoaba macdonaldi juveniles was evaluated. Seven isonitrogenous and isolipidic diets were formulated containing 15–100% SPC (SPC15, SPC30, SPC45, SPC60, SPC75, SPC90 and SPC100) to replace fishmeal (FM‐protein), and a FM‐protein‐based diet without SPC was used as a reference diet (RD). Each diet was randomly assigned to triplicate groups of 20 totoaba (50 ± 1.0 g) and was fed twice daily to apparent satiation. After 60 days of experiment, effects on totoaba were evaluated. Growth performance in fish fed RD to SPC45 was similar. The maximum FM‐protein replacement for weight gain (g kg ABW^?1 day^?1) was estimated to be 34.17% using a broken‐line model. In vitro digestibility of fish fed RD, SPC15 and SPC30 was similar. Trypsin activity was higher in fish fed the RD (9.38 ± 0.52 mU × 10^?3 mg protein^?1. Chymotrypsin activity was similar in fish fed RD, SPC15 and SPC30. Activity of alkaline protease and phosphatase was similar in fish fed RD, SPC15 and SPC30. Red blood cells (RBC) were the highest in fish fed RD to SPC60. Fish fed the RD, SPC15 and SPC30 present the highest haematocrit (HT) and haemoglobin (HB) content. Diets SPC90 and SPC100 presented similar MCV and MCHC. Total protein (TP) profile overall decreased in fish fed SPC90 and SPC100, pointing to nutritional hypoproteinemia due to deficient digestion and absorption. These results indicate that SPC‐based diets could be used efficiently by totoaba with FM‐protein replacement of less than 45%.     

Growth, uptake and retention of nitrogen and phosphorus, and absorption of other minerals in Atlantic salmon Salmo salar fed diets with fish meal and soy–protein concentrate as the main sources of protein

An experiment with 0.2‐kg Atlantic salmon, Salmo salar in saltwater was conducted to determine if the fish could grow normally, and maintain normal nitrogen (N) and mineral balance when fed a diet with the majority of the protein (75%) derived from soy‐protein concentrate (SPC). The two diets contained 50% SPC and 15% fish meal (FM) or 60% FM as the sources of protein. No calcium phosphate was added to the diets in order to assess the availability of P from the ingredients. A second aim was to investigate if whole‐body concentrations of essential elements and growth were related in individual salmon. Growth (SGR=0.88–0.89) was similar in salmon fed the two diets, and the fish nearly doubled their body weights during the 84 days of feeding. Feed conversion was more efficient for the FM diet (0.81 kg intake kg^?1 gain) than for the SPC diet (0.89 kg kg^?1). The intake of N was similar, faecal loss of N was lower, while the metabolic N excretion was greater in the fish fed the FM than the SPC diet. This resulted in a total excretion of 35.4 g N kg^?1 gain for the salmon fed the FM diet and 35.5 g N for the fish fed the SPC diet. Both the intake, faecal and metabolic excretion of P were higher in the fish fed the FM diet than the SPC diet, resulting in a total excretion of 10.5 g P kg^?1 gain for the FM diet and 7.2 g P for the SPC diet. Whole‐body concentrations of Ca, Mg, P and Zn were lower in the fish fed the SPC diet, while the Ca–P ratio was decreased, both when compared with the fish at the start of the experiment, and the fish fed the FM diet. The differences in elemental composition were ascribed to a combination of reduced availability of elements due to phytic acid and lower concentration of elements in the SPC than in the FM. No reduction in growth of individual fish, which could be ascribed to reduced availability of essential elements, was seen.     

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

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.     

Supplementation of Protein Hydrolysates to a Low‐fishmeal Diet Improves Growth and Health Status of Juvenile Olive Flounder,Paralichthys olivaceus

An 11‐wk feeding trial was conducted to evaluate three different protein hydrolysates as feed ingredients in high‐plant‐protein diets for juvenile olive flounder. Five experimental diets were fed to juvenile olive flounder to examine the effect of three different protein hydrolysates on growth performance, innate immunity, and disease resistance against bacterial infection. A basal fishmeal (FM)‐based diet was regarded as a high‐FM diet (HFM) and a diet containing soy protein concentrate (SPC) as a substitute for 50% FM protein was considered as a low‐FM diet (LFM). Three other diets contained three different sources of protein hydrolysates, including shrimp, tilapia, and krill hydrolysates (designated as SH, TH, and KH), replacing 12% of FM protein. All diets were formulated to be isonitrogenous and isocaloric. Triplicate groups of fish (15.1 ± 0.1 g) were handfed one of the diets to apparent satiation twice daily for 11 wk and subsequently challenged against Edwardsiella tarda. Growth performance and feed utilization of fish fed hydrolysate‐supplemented diets were significantly improved compared to those of fish fed the LFM diet. Dietary inclusion of the protein hydrolysates significantly enhanced apparent digestibility of dry matter and protein of the diets. In the proximal intestine, histological alterations were observed in the fish fed the LFM diet. The fish fed the hydrolysate diets showed significantly longer mucosal fold and enterocytes and greater number of goblet cells compared to fish fed the LFM diet. Respiratory burst activity was significantly higher in fish fed the TH and KH diets than fish fed the LFM diet. Significantly higher immunoglobulin levels were found in fish fed SH and KH diets compared to those of fish fed the LFM diet. Dietary inclusion of the protein hydrolysates in SPC‐based diets exhibited the highest lysozyme activity. Significantly higher superoxide activity was observed in groups of fish fed the KH diet. Fish offered the protein hydrolysates were more resistant to bacterial infection caused by E. tarda. The results of this study suggest that the tested protein hydrolysates can be used as potential dietary supplements to improve growth performance and health status of juvenile olive flounder when they were fed a LFM diet.     

Partial replacement of fish meal by soy protein concentrates in diets for a new Japanese strain of juvenile soft‐shelled turtle,Pelodiscus sinensis

An 8‐week experiment was conducted to evaluate the effects of dietary fish meal (FM) replaced by soybean protein concentrate (SPC) on Japanese strain of soft‐shelled turtle, Pelodiscus sinensis juveniles. Diets were formulated to replace FM protein by SPC at 0, 15, 30, 45, 60 or 60% supplemented with phytase (2000 FTU kg^?1) (designated as S0, S15, S30, S45, S60 and S60P, respectively), and each diet was fed to triplicate groups. The results showed that the growth was significantly lower when dietary SPC replaced more than 45% FM. The turtles fed the S15 or S30 diet showed comparable feed and protein utilization efficiency compared with the S0 group, whereas more than 30% replacement of FM adversely affected these values. Increasing dietary SPC levels significantly lowered the apparent digestibility coefficients (ADC) of dry matter, protein, lipid, phosphorus and gross energy. Whole‐body protein, ash and phosphorus content showed a declining trend when dietary SPC levels increased, while body lipid and moisture content were unaffected. When the turtles were fed diets with increasing levels of SPC, serum total protein concentration, alkaline phosphatase and catalase activities decreased with a corresponding increase in glutamic pyruvic transaminase activity. Turtles fed the S60P diet showed comparable growth performance and feed utilization efficiency to the S40 group, and were superior to the S60 group. The present study showed that SPC could successfully substitute for 30% FM protein in the diets for P. sinensis juveniles, and the maximum effective substitution may be greater if exogenous phytase was added.     

Fishmeal can be completely replaced by soy protein concentrate by increasing feeding frequency in Nile tilapia (Oreochromis niloticus GIFT strain) less than 2 g

An 8‐week growth trial was conducted to determine the effects of complete replacement of fishmeal protein by soy protein concentrate (SPC) on growth performance of Nile tilapia (Oreochromis niloticus GIFT strain) fry (initial body weight 1.6 ± 0.0 g). In control diet, 135 g kg^‐1 fishmeal was used, and in the other two diets, 100% of fishmeal was replaced by SPC supplemented with or without methionine hydroxy analogue (MHA) according to the content in FM diet. Fish of FM group were fed twice daily. Fish of SPC6 group were fed SPC diet six times daily. Fish of SPCM group were fed twice (SPCM2) or six times (SPCM6) daily. The results showed that complete replacement of fishmeal with SPC did not affect survival, condition factor, visceralsomatic index of Nile tilapia. Feed intake (FI) and feed conversion ratio (FCR) of fish in SPCM2 and SPC6 groups were higher than those in FM and SPCM6 groups. Specific growth rate (SGR) of fish in SPCM6 group was highest among four treatments. Productive protein value (PPV) of SPCM2 and SPC6 groups were significantly lower than that of FM group. Fishmeal could be completely replaced by SPC without negative effect on growth by MHA supplementation and increasing feeding frequency.     

Effect of temperature on digestibility,growth performance and nutrient utilization of corn distiller’s dried grains with soluble (DDGS) in Common carp juveniles

The aim of this trial was to study the digestibility of corn distiller's dried grains with soluble (DDGS) in Common carp juveniles at two water temperatures 20°C and 30°C. DDGS digestibility was determined based on the substitution of 30% of a reference diet by test DDGS. Three hundred and sixty Common carp juveniles (average weight, 40 ± 7 g) were distributed in thermo‐regulated recirculation water system equipped with twelve 1m³ fibreglass tanks (30 fish per tank), which were allotted to four experimental group in triplicates. Half of the experimental groups were maintained at 20°C, whereas the other half were exposed to 30°C. Juveniles reared under different temperature regimes were fed either of the two diets, with or without DDGS (DDGS diet or reference diet), to evaluate the interaction effect between water temperature and nutrient digestibility of corn DDGS in Common carp. Diet and water temperature interaction was effective in modulating the response of dry matter digestibility of DDGS ingredient, and digestibility was found higher in juveniles reared at 20°C compared with 30°C. Growth, feed efficiency and protein efficiency were higher at 20°C compared with 30°C. Whole body csomposition of Common carp juveniles was found unaffected due to diet and water temperature interaction. Overall, it is concluded that digestibility and growth performance of Common carp is better at 20°C compared with 30°C, and DDGS has high potential for inclusion in diets of Common carp.     

Alternative protein sources in diets for Japanese flounder Paralichthys olivaceus (Temminck and Schlegel): II. Effects on nutrient digestibility and digestive enzyme activity

An 8‐week feeding trial was conducted to compare the effects of dietary protein sources on nutrient digestibility and digestive enzyme activity. Four experimental diets were formulated to contain one of the following as the sole protein source: fish meal (FM), fish protein concentrate (FPC), soy protein concentrate (SPC) and soy protein isolate (SPI). Each diet was randomly assigned to triplicate aquaria stocked with 25 Japanese flounder (Paralichthys olivaceus) each. The dry matter, crude protein and energy digestibility and individual amino acid availability of the SPC‐based diet were significantly lower than those of the other diets. The crude lipid digestibility of soy protein‐based diets was significantly lower than that of the FM‐based diet. The pepsin/protease activity was significantly higher in fish fed fish protein‐based diets compared with fish fed soy protein‐based diets. The lipase activity in fish fed the SPI‐based diet was the highest among the dietary treatments. These results indicate that P. olivaceus can effectively digest the protein from FPC and SPI (but not SPC) as well as FM. The low protein digestibility and amino acid availability of the SPC‐based diet may be related to the non‐protein compounds present in SPC, whereas the low‐lipid digestibility of soy protein‐based diets may contribute to the undigested soy protein fractions and/or the alcohol‐soluble components.     

Growth and feeding responses of the mutton snapper,Lutjanus analis (Cuvier 1828), fed on diets with soy protein concentrate in replacement of Anchovy fish meal

This study evaluated the growth (first phase) and feeding responses (second phase) of juvenile mutton snapper fed four isonitrogenous and isoenergetic diets with increasing levels of soy protein concentrate (SPC) in substitution to fish meal (FM). The FM was replaced by SPC at 0% (basal diet, SPC000), 33% (SPC130), 57% (SPC214) and 77% (SPC300). After 95 days of rearing, fish fed SPC300 attained a significantly lower body weight (54.9 ± 13.2 g) compared with those fed diets SPC000, SPC130 and SPC214 (76.5 ± 14.0 g, 73.9 ± 13.8 g and 70.5 ± 14.0 g respectively). Fish yield increased significantly from 891 ± 36 g m^?3 for fish fed SPC300 to an average of 1099 ± 111 g m^?3 for other diets. A maximum fish body weight gain of 0.60 ± 0.05 g day^?1 and a maximum specific growth rate of 1.47 ± 0.07% day^?1 were achieved for SPC000. Behavioural assays conducted during 10 days revealed the loss in fish growth with diets containing higher levels of SPC was due to a decline in feed intake. Low feed intake driven by a poor feed palatability appeared to have been a major obstacle against higher inputs of SPC in diets for mutton snapper.     

Ammonia nitrogen excretion in Mandarin Fish (Siniperca chuatsi) and Grass Carp (Ctenopharyngodon idellus) fed practical diets: the effects of water temperature

To understand the actual production of fish culture about the utilization of dietary protein and excreta impact on the environment between mandarin fish (Siniperca chuatsi) and grass carp (Ctenopharyngodon idellus), the study to investigate the effect of temperatures (19 ± 0.5°C, 24 ± 0.5°C and 29 ± 0.5°C) on ammonia‐N excretion in mandarin fish and grass carp under fed and fasted states was conducted. These two species were fed a practical diet containing 325.2 g kg^?1 crude protein at 3% body weight per day. The ammonia‐N excretion rate was significantly increased when temperature increased from 19 to 29°C, and a linear relationship between ammonia‐N excretion rate and temperature. The maximum ammonia‐N excretion levels of mandarin fish and grass carp were observed at 4–8 h and 2–4 h after feeding, respectively, and the minimum values for both species were observed at 24 h after feeding. Under the feeding condition, mandarin fish had a lower ammonia‐N excretion level compared to grass carp at 24°C and 29°C. The average amount of ammonia‐N excreted by mandarin fish at 24 h is significantly higher than grass carp under fasting conditions, except 19 ± 0.5°C. These results indicated that mandarin fish might make better use of protein at higher temperature than grass carp when fed practical diets in commercial production. These results of this study suggested that mandarin fish had a lower ammonia‐N excretion level compared with grass carp, making a less contribution to environmental loading in an intensive fish culture.     

Formulation of low phosphorus loading diets for carp (Cyprinus carpio L.)

This study focuses on reducing total phosphorus loading (T-P) from carp culture through improved feed formulation. Since phosphorus (P) contained in fish meal (FM) mainly in the form of tricalcium phosphate is not available to carp, which lack a stomach, the reduction of FM from their diets is effective for lowering T-P. Thus in this experiment, six diets (crude protein < 35%, digestible energy > 3.5 kcal g⁻¹) were designed by substituting FM (10%−25%) with alternate protein ingredients such as poultry feather meal (PFM; 5%−10%), blood meal (BM; 5%−7%) and defatted soybean meal (dSBM; 4%−9%). All diets followed the Kasumigaura ‘Feed Standard’. The total dietary P was 1.0%−1.4% and water extractable P available to carp was 0.66%−0.71%, the levels meeting the dietary requirement of carp. A feeding trial was conducted with juvenile carp (4.6 ± 0.7 g) for 12 weeks at a mean water temperature of 23.7°C. The T-P loading from fish fed the different diets was estimated based on absorption and retention of dietary P. Growth performance corresponded to increasing levels of FM inclusion, being highest in the fish fed 25% FM diet; however, the decrease in T-P was achieved at the lower FM levels. The T-P (based on P retention) ranged from 8.9 to 11.7 kg t⁻¹ production, much lower than that from the commercial diets (9.1–26.4 kg t⁻¹ production). These results indicated that the reduction of FM levels in carp diets to 15%−20% through the combined use of PFM, BM and dSBM effectively lowered T-P. Moreover, the formulated diets were also found to be better than commercial diets in lowering the N loading from carp culture.     

Comparative nutritional value of <Emphasis Type="Italic">Jatropha curcas</Emphasis> protein isolate and soy protein isolate in common carp

Jatropha seed cake (JSC) is an excellent source of protein but does contain some antinutritional factors (ANF) that can act as toxins and thus negatively affect the growth and health status of fish. While this can limit the use of JSC, detoxified Jatropha protein isolate (DJPI) may be a better option. An 8-week study was performed to evaluate dietary DJPI to common carp Cyprinus carpio. Five iso-nitrogenous diets (crude protein of 38%) were formulated that consisted of a C _ontrol (fish meal (FM) based protein), J ₅₀ or J ₇₅ (50 and 75% of FM protein replaced by DJPI), and S ₅₀ or S ₇₅ (50 and 75% of FM protein replaced by soy protein isolate, SPI) and fed to triplicate groups of 75 carp fingerlings (75; av. wt. ± SD; 11.4 ± 0.25 g). The growth, feeding efficiencies, digestibility, plasma biochemistry, and intestinal enzymes were measured. Results showed that growth performance of fish fed the S ₇₅- or DJPI-based diets were not significantly different from those fed the C _ontrol diet, while carp fed the S ₅₀ had significantly better growth than the J ₇₅ diet. Fish fed the J ₇₅ diet had significantly lower protein and lipid digestibility as well as significantly lower intestinal amylase and protease activities than all other groups. However, all plant protein-based diets led to significantly higher crude protein, crude lipid, and gross energy in the body of common carp compared to the control treatment. Plasma cholesterol and creatinine significantly decreased in the plant protein fed groups, although plasma triglyceride as well as the red blood cells count, hematocrit, albumin, globulin, total plasma protein, and lysozyme activity were higher in plant protein fed groups compared to FM fed group. White blood cells, hemoglobulin concentration, alkaline phosphatase and alanine transaminase activities, and glucose level in blood did not differ significantly among treatments. The results suggest that the DJPI is non-toxic to carp and can be used to replace FM in the diets of common carp up to 75%, but further research to potentially reduce some inherent ANF within this protein source, such as non-starch polysaccharides, may improve nutrient utilization.     

Effects of high carbohydrate and high lipid diets on growth,body composition and glucose metabolism in southern catfish at two temperatures

The effects of high carbohydrate and high lipid diets on the growth, body composition and glucose metabolism in the southern catfish were determined at 17.5 °C and 27.5 °C. At each temperature, the feeding rate, specific growth rate and protein productive value decreased with increasing dietary carbohydrate (P<0.05). Feed efficiency and protein efficiency ratio were lower in the fish fed a high dietary carbohydrate diet at 17.5 °C, but were not significantly different between diets at 27.5 °C. Plasma glucose and activities of pyruvate kinase and glucose‐6‐phosphate dehydrogenase were higher in fish reared at 27.5 °C than those reared at 17.5 °C, and within each temperature, they were higher in fish fed the high‐carbohydrate diet. Hepatosomatic index was higher in fish fed the high‐carbohydrate diet than those fed the high‐lipid diet at 27.5 °C, but no significant difference was found at 17.5 °C. The results indicate that higher temperatures enhance glycogen deposition and lipogenous enzyme activities when fed with a high‐carbohydrate diet; thus, at higher temperatures, this fish uses carbohydrate more efficiently for protein sparing.     

Interactive effects of dietary cholesterol and protein sources on growth performance and cholesterol metabolism of Japanese flounder (Paralichthys olivaceus)

A feeding trial was conducted to compare the effects of supplemental cholesterol in fish meal (FM), fish protein concentrate (FPC), soy protein isolate (SPI) and soy protein concentrate (SPC)‐based diets on growth performance and plasma lipoprotein levels of Japanese flounder (Paralichthys olivaceus). Eight isonitrogenous and isocaloric diets including FM, FPC, SPI or SPC as sole protein source with or without supplementation with 10 g cholesterol kg^?1 diet were fed to juvenile fish for 8 weeks. Dietary cholesterol supplementation significantly increased the feed intake and specific growth rate in fish fed SPI‐based diets, but decreased those in fish fed FPC‐based diets. In addition, cholesterol supplementation significantly increased the level of cholesterol and ratio of low‐density lipoprotein cholesterol to high‐density lipoprotein cholesterol in plasma of fish fed fish protein‐based diets, whereas no effects were observed in fish fed soy protein‐based diets. The hepatic lipid content of fish fed FPC‐, SPI‐ or SPC‐based diets were significantly increased by supplemental cholesterol, but no influence was observed in fish fed FM‐based diets. These results suggested that dietary protein source modify the growth‐stimulating action of cholesterol; cholesterol supplementation may increase the arteriosclerotic lesion in fish fed fish protein‐based diets and the incidence of fatty liver in fish fed soy protein‐based diets.     

Suitability of genetically modified soybean meal in a dietary ingredient for common carp Cyprinus carpio

The effect of genetically modified (GM) soybean meal (SBM) in a feed ingredient on growth performance of common carp was investigated in comparison to nonGM SBM. GM SBM was included at 34 and 48% in two experimental diets that were formulated with fish meal (FM) to obtain approximately 38% protein in diet. Two other experimental diets were formulated to contain the same levels of nonGM SBM. The diets were fed to juvenile common carp (22 g initial mean weight) for 12 weeks. The cauliflower mosaic virus (CaMV) 35S promoter fragment (205 base pairs) of the GM SBM was examined in fish muscle and blood samples at the twelfth week. From the twelfth week, the GM groups were fed with nonGM diets to determine the residual span of the transferred promoter fragment. There was no significant difference in growth and feed performance between GM and nonGM groups at two inclusion levels after 12 weeks. The CaMV 35S promoter fragment was not detected in fish muscles or blood receiving either level of GM SBM diet. The results demonstrated that the availability of GM SBM was similar to that of nonGM SBM and the GM SBM would be a suitable and safe ingredient in feed for common carp.