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.     

Replacement of fish meal with poultry by-product meal in diets formulated for the humpback grouper, Cromileptes altivelis

An eight-week feeding trial was conducted to examine the possibility of replacing fish meal with poultry by-product meal (PBM) at high inclusion levels in the diets of the humpback grouper, Cromileptes altivelis, a carnivorous marine tropical fish. Six isolipidic (12%) and isoproteic (50%), experimental diets were formulated to contain graded levels of PBM. Fish meal protein was replaced with a feed-grade PBM at 50, 75 or 100% level (FPBM50, FPBM75, FPBM100, respectively), or a pet food grade PBM at 75 or 100% replacement level (PPBM75 and PPBM100, respectively). The control diet contained Danish fish meal as the sole protein source. The experimental diets were fed close to apparent satiation, twice a day to triplicate groups of humpback grouper fingerlings (12.4 ± 0.2 g). The grouper fingerlings were randomly distributed into groups of 15 fish in cylindrical cages (61 cm depth and 43 cm diameter) and placed in a 150-ton seawater polyethylene tank. Except for fish fed the FPBM100 diet, growth performance, survival, and feed utilization efficiency for fish fed PBM-based diets were not significantly lower (P > 0.05) compared to fish fed the control diet. The PBM source and dietary level did not significantly affect (P > 0.05) the hepato- and visero-somatic indices or the condition factor of fish. Dry matter and protein apparent digestibility coefficients (ADC) of the diets decreased with increasing dietary PBM, and ranged from 64.3-71.5% and 86.2 to 91.2%, respectively. High values (91.7 to 96.7%) for lipid ADC were observed in all diets, with no significant differences among dietary treatments. Whole-body moisture and lipid contents of the fish were not affected by the inclusion of PBM in the diets. With the exception of fish fed the FPBM100 diet, whole-body protein of fish fed the PBM-based diets was slightly higher than that of fish fed the control diet. There was a trend of increased whole-body ash with the increase in dietary levels of PBM. The results from this study indicate that good quality terrestrial PBM can successfully replace more than half the protein from marine fish meal in the diets for humpback grouper. However, total replacement of fish meal with PBM might be constrained by lowered nutrient digestibility and limiting essential amino acids, especially lysine and methionine.     

Effect of totally or partially replacing fish meal by alternative protein sources on growth of African catfish Clarias gariepinus (Burchell, 1822) reared in concrete tanks

A 12‐week feeding trial was carried out in concrete tanks to examine complete and partial replacement (75%) of fish meal (FM) with poultry by‐product meal (PBM), meat and bone meal (MBM) and soybean meal (SBM) in practical feeds for African catfish Clarias gariepinus. Triplicate groups of fish (initial body weight ranged from 90.33 to 93.93 g fish⁻¹) were fed seven isonitrogenous and isocaloric diets of 20% digestible protein and 300 kcal 100 g⁻¹ of digestible energy. The control contained 25% herring meal, whereas in the other six diets, PBM, MBM and SBM replaced 75% or 100% of the FM. Final body weight (FBW) and specific growth rate (SGR) of the fish fed diets containing PBM (75% and 100%), SBM (75% and 100%) and MBM (75%) were all higher, but not significantly different than those for fish fed the control diet. Replacing 100% of the FM by MBM significantly lowered FBW and SGR. Concerning whole body composition, there were no significant differences in ash and gross energy content of whole‐body among fish; fish fed diets containing PBM‐100% recorded significantly lower protein content compared with the control diet, while fish fed diet SBM‐100% recorded significantly lower moisture content compared with the control diet. Also fish fed diets SBM‐100% and PBM‐75% recorded higher lipid and gross energy contents compared with the control diet. The study revealed that satisfactory growth and feed utilization responses could be achieved through the replacement of FM by PBM, SBM and MBM in the diet of African catfish.     

Enhancing the growth of Nile tilapia larvae/juveniles by replacing plant (gluten) protein with algae protein

Diets incorporating different levels of corn gluten meal replacement using biofuel algae or Spirulina protein at 0%, 25%, 50%, 75% and 100% were evaluated for larval/juvenile stage of Nile tilapia (Oreochromis niloticus). Fish averaging 0.02 g were divided into groups of 50. There were three replicates per every dietary treatment that were fed one of six diets for 11 weeks. Corn gluten protein was replaced with algae on the protein basis. All diets were supplemented with 1.5% lysine and 0.5% methionine. The experimental diets were formulated to contain 37 ± 2.8% protein and 14 ± 4.3% lipid in the form of fish oil and soybean lecithin (phospholipids source). The results indicated that algae positively affected feed consumption and fish growth up to the 50% replacement and then performance was depressed. Significant differences in concentration of individual minerals (Al, Fe, Zn and Cu) in the whole fish body were found. Mineral composition of algae might have affected growth when diets which contained more than 75% of plant protein were replaced with microalgae. These findings suggest that up to 50% of dietary corn gluten meal protein can be replaced with microalgae which significantly enhance fish growth.     

Total replacement of fish meal with animal protein sources in Nile tilapia,Oreochromis niloticus (L.), feeds

The effects of total replacement of dietary fish meal (FM) with animal protein sources on the growth, feed efficiency and profit indices of Nile tilapia, Oreochromis niloticus (L.), were investigated. Shrimp meal (SM), blood meal (BM), meat and bone meal (MBM), BM + MBM mix and poultry by-product meal (PBM) replaced FM in six isonitrogenous (30% crude protein), isocaloric (400 kcal GE 100 g^–1) diets. The diets were fed to O. niloticus fingerlings (12.5 g) to satiation twice a day for 150 days. The growth of fish fed SM, PBM and MBM was not significantly different from those fed the FM-based diet, while feed conversion and protein efficiency ratios were significantly retarded. Further reduction in fish performance was noticed when BM or BM + MBM replaced FM in the control diet. Cost–benefit analyses of the test diets indicated that these sources were economically superior to FM. The PBM-based diet produced higher carcass lipid than other diets. Fish fed SM, MBM and PBM diets had significantly higher ash contents (P < 0.05).     

Improvement of quality of sesame Seasamum indicum seed meal protein with supplemental amino acids in feeds for rohu Labeo rohita (Hamilton) fingerlings

An 8-week feeding trial was conducted in a static indoor rearing system to examine the effects of partial substitution of fish meal (FM) protein with sesame seed meal protein with and without supplemental amino acids in diets for rohu Labeo rohita fingerlings (average weight 3.82 ± 0.05 g). Before incorporation into diets, sesame Seasamum indicum seed meal was fermented with lactic acid bacteria Lactobacillus acidophilus in order to reduce/eliminate the antinutritional factors tannin and phytic acid present in it. Twelve experimental diets (diets D1 to D12) were formulated replacing the FM protein from a reference diet with sesame seed meal protein at different levels (four sets of diets, of which each set of three diets contained 30%, 40% and 50% replacement of FM protein by sesame seed meal protein respectively). Diets D1 to D3 were not supplemented with any amino acid. Lysine was supplemented to diets D4 to D6. Diets D7 to D9 were supplemented with methionine–cystine (together), and diets D10 to D12 contained lysine and methionine–cystine (together). Lysine and methionine–cystine were added to the diets at 5.7% and 3.1% of dietary protein respectively. The groups of fish fed diets without any supplemental amino acids had significantly lower percentage weight gain, specific growth rate (SGR) and higher feed : gain ratio (FGR) than the groups of fish fed on other experimental diets. The addition of lysine and methionine–cystine to the diet in which 50% of FM protein was replaced by sesame meal protein (diet D12) significantly improved fish weight gain and FGR. The percentage live weight gain and SGR values differed significantly (P < 0.01) from each other in the fish fed diets D10 to D12, which were supplemented with all three amino acids. The results of the present study suggest that rohu fingerlings can effectively utilize the supplemented amino acids and that sesame seed meal protein can replace up to 50% of FM protein in the diets for rohu if the sesame seed meal is properly processed (fermented) and supplemented with deficient amino acids.     

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).     

Effect of Dietary Lipid Levels on Growth,Feed Conversion,and Muscle Composition of the Walking Catfish,Clarias batrachus

Feeding trials were conducted to determine the feasibility of using spray-dried blood meal (EM) or enzyme-hydrolyzed (EH) and low-ash (LA) poultry products to partially replace fish meal (FM) in diet formulations for palmetto bass. Pelleted diets were formulaled with EM protein replacing 10, 25, or 50% of the FM protein and either EH or LA poultry products replacing approximately 25, 50, or 75% of the FM protein. All diets were formulated to contain 14kJ GE energy/g and 35% crude protein. Fish fed a die1 in which BM replaced 50% of the protein supplied by FM had significantly (P < 0.05) lower weight gain and feed efficiency compared to fish fed the control diet at the end of 6 and 12 weeks. Total body lipid was significantly higher for those fish receiving diets with 10 or 25% BM. However, there were no differences in total body moisture, protein, or ash. When either EH or LA protein rep     

Effects of complete fish meal replacement by rice protein concentrate with or without lysine supplement on growth performance,muscle development and flesh quality of blunt snout bream (Megalobrama amblycephala)

An 8‐week feeding trial was conducted to evaluate the effects of fish meal (FM) replacement by rice protein concentrate (RPC) with supplementation of microcapsule lysine (ML) or crystalline lysine (CL) on growth performance, muscle development and flesh quality of blunt snout bream. Four isonitrogenous and isoenergetic diets were formulated, including FM diet (containing 50 g/kg FM), RPC diet (FM replaced by RPC), MRPC diet (FM replaced by RPC with ML supplementation) and CRPC diet (FM replaced by RPC with CL supplementation). Fish fed FM diet had significantly higher weight gain, feed efficiency, protein efficiency ratio and nitrogen and energy utilization than that of RPC group, but showed no statistical difference with other treatments. In addition, fish fed RPC diet showed higher muscle fibre frequency in the 20‐ to 50‐μm class but lower >50‐μm class and higher cooking loss than that of the other groups. Furthermore, no significant difference was found in whole‐body proximate compositions, frequency distribution of <20‐μm‐diameter fibres, texture, muscle content, collagen, pH 24 hr post‐mortem and sensory quality. The results showed that RPC supplemented with ML or CL could replace fishmeal without any adverse effects on growth performance and flesh quality for blunt snout bream.     

Partial replacement of fishmeal with corn gluten meal,pea protein isolate and their mixture in diet of black sea bream (Acanthopagrus schlegelii) juveniles: Effects on growth performance,feed utilization and haematological parameters

Corn gluten meal (CGM), pea protein isolate (PPI) and their mixture (CPP, 1:1 ratio) were evaluated as fishmeal (FM) alternatives in black sea bream (Acanthopagrus schlegelii) juveniles (9.02 ± 0.12 g). A FM diet was designed as control, and other six diets had 20% and 40% FM protein replaced by CGM, PPI and CPP, respectively, with the supplementation of crystalline methionine, arginine and lysine. After the 8‐week feeding trial, significantly lower weight gain was found in fish fed the 40% CGM diet (p < .05), whereas other treatments had no statistical difference (p > .05). The values of feed efficiency ratio and feed intake, as well as proximate compositions of muscle and whole body, were not significantly influenced in all treatments. Apparent digestibility coefficients (ADCs) of dry matter, crude protein, threonine, valine, methionine, isoleucine, leucine, phenylalanine and lysine were significantly influenced by protein source. Fish fed the 40% CGM diet had significantly higher content of essential amino acid in muscle than that of the 20% PPI diet. Fish fed the 40% CGM diet had significantly lower content of serum cholesterol than other treatments (p < .05). Elevated serum superoxide dismutase activity was found in fish fed the 40% plant protein diets. In conclusion, between 20% and 40% FM protein could be replaced by CGM, while about 40% FM protein derived from PPI and CPP could be applied in black sea bream.     

Replacing Fish Meal with Rendered Animal Protein Ingredients in Diets for Malabar Grouper,Epinephelus malabaricus,Reared in Net Pens

The potential of using rendered animal protein ingredients, poultry by‐products meal (PBM), meat and bone meal (MBM), and feather meal (FM), to replace fish meal in diets for malabar grouper, Epinephelus malabaricus, was evaluated in a 10‐week net pen experiment. Triplicate groups of fish (initial body weight 50.2 g) were fed eight isonitrogenous and isocaloric diets formulated to contain 52% crude protein and 9% crude lipid. The control diet contained 50% herring meal, whereas in the remaining seven diets, PBM was incorporated at 11.9 (PM1), 23.8 (PM2), and 35.7% (PM3) to replace 25, 50, and 75% of the fish meal; MBM was incorporated at 14.5 (MM1) and 29.0% (MM2) to replace 25 and 50% of the fish meal; and FM was incorporated at 9.4 (FM1) and 18.8% (FM2) to replace 25 and 50% of the fish meal. A raw fish (RF) diet was used as comparison to assess growth performance of fish fed the formulated diets. Feed intake was lower in fish fed the diets PM3 and FM2 than fish fed the control diet. There were no significant differences in weight gain (WG), final body weight (FBW), nitrogen retention efficiency (NRE), energy retention efficiency (ERE), and total nitrogen waste output (TNW) between fish fed the control diet and the diets PM1, PM2, PM3, MM1, MM2, and FM1. Fish fed the diet FM2 had lower WG, FBW, NRE, and ERE but higher TNW than that of fish fed the control diet. Feed conversion ratio (FCR) was higher in fish fed the diets MM2, FM1, and FM2 than fish fed the control diet. At the end of the experiment, there were no significant differences in whole‐body content of moisture, crude protein, and crude lipid among fish fed the formulated diets. WG, FBW, and TNW of fish fed the diet RF were higher, while FCR and NRE were lower than that of fish fed the control diet. No significant differences were found in feed intake, ERE, and whole‐body composition between fish fed the diet RF and the control diet. Results of the present study suggest that dietary fish meal level for malabar grouper can be lowered from 50 to 38% by incorporating PBM, MBM, or FM.     

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.     

Evaluation of Cow Pea Seed Meal,Vigna sinensis,as a Dietary Protein Replacer for Nile tilapia,Oreochromis niloticus (L.), Fingerlings

The main objectives of this study were to evaluate the effect of partial and total replacement of fish meal (FM) protein by cow pea seed meal (CPSM) protein in practical diets on growth performance, feed utilization, and body composition of Nile tilapia, Oreochromis niloticus (L.). Fish of an average initial weight of 4.6 ± 0.2 g were stocked in 15 glass aquariums (80 L each) at a rate of 15 fish per aquarium. FM protein (30% of the diet) was used as the sole source of animal protein in the control diet. Percent replacement of FM by CPSM on the basis of crude protein were as follows: 0% (control diet A), 25% (diet B), 50% (diet C), 75% (diet D), and 100% (diet E). Diets were fed to fish at a rate of 4% of the total fish biomass daily, for a period of 16 wk. The results of this study revealed that the fish fed control diet A (100% FM) had the best average final body weight, specific growth rate (SGR %/d), weight gain (g/fish), weight gain %, while the poorest results for all parameters were obtained with fish fed diet E (100% CPSM). The same parameters of fish fed diets B (25% CPSM) and C (50% CPSM) were not significantly different (P > 0.05) from those of fish fed the control diet A. Feed utilization parameters of fish fed diets A, B, C, and D were better than for diet E. Proximate composition of whole‐body moisture and ash contents were not significantly different (P > 0.05) among all experimental diets and control diet. Whole‐body protein contents for fish fed diets B and C were superior to the control diet A. Incorporation of CPSM in the diets significantly increased whole‐body fat content. Incorporation of CPSM in the diets significantly decreased apparent digestibility coefficient of crude protein crude fat and energy. Diets B and C were not significantly different from control diet A. Therefore, these findings suggest that up to 50% of FM protein can be replaced by CPSM protein in Nile tilapia diets without any adverse effects on growth performance, feed utilization, body composition, and digestibility.     

Effect of substituting fishmeal with corn protein concentrate on growth performance,nutrient utilization and skin coloration in red hybrid tilapia,Oreochromis sp.

The objective of this study was to evaluate the effects of fishmeal (FM) replacement with corn protein concentrate (CPC) on growth performance, nutrient utilization, gut morphology and skin coloration of red hybrid tilapia, Oreochromis sp. Five isonitrogenous (350 g/kg crude protein) and isolipidic (10 g/kg lipid) diets were formulated to contain CPC that substituted 0%, 25%, 50%, 75% or 100% FM. Diets were fed to triplicate groups of tilapia (mean initial weight, 10.33 ± 0.02 g) twice daily for 63 days. The results showed that replacing up to 50% FM in red hybrid tilapia diet with CPC did not show any significant adverse effects on growth, feed utilization, haematocrit counts, condition factor and gut morphology of tilapia (p > 0.05). However, replacing 75% or 100% FM with CPC had deleterious effects (p < 0.05). Carotenoids in CPC contributed to skin yellowness, which was significantly higher in the diet where 100% FM was replaced with CPC. Using regression analysis, the optimal substitution level of FM by CPC was estimated at 25% for percentage weight gain, 33% for FCR and 29% for protein efficiency ratio. CPC could be used as a single plant protein source to substitute up to 50% FM in red hybrid tilapia diets.     

Isotopic Evaluation of the Nutritional Contribution of Poultry By‐product Meal and Fish Meal to the Growth of Pacific White Shrimp,Litopenaeus vannamei

The nutritional contribution of the dietary nitrogen supplied by poultry by‐product meal (PBM) and fish meal (FM) to the somatic growth of Pacific white shrimp, Litopenaeus vannamei, was assessed by means of stable isotope analysis. Seven experimental diets were formulated with different proportions of PBM replacing FM. Practical diets were formulated to replace 0, 35, 50, 65, 80, 95, and 100% of FM with PBM, on a dietary nitrogen basis. At the end of the experiment, there were no significant differences in survival among dietary treatments (89 ± 5%); however, significant differences in final wet weights were observed. Diets having FM replacement levels of 35 and 50% with PBM promoted mean final weights (708–789 mg) similar to those observed in shrimps fed on diet containing 100% FM (874 mg). Shrimp final mean weight significantly decreased as a function of PBM inclusion (r = −0.98) owing to the use of only two dietary nitrogen sources and by possible nutritional restrictions as PBM levels increased. The relative proportions of dietary nitrogen supplied by PBM and FM were incorporated in muscle tissue at proportions that were statistically similar to those established in the dietary formulations.     

Partial and complete replacement of fish meal by broad bean meal in feeds for Nile tilapia, Oreochromis niloticus, L., fry

A 16‐week feeding experiment was conducted to study the feasibility of using broad bean meal (BBM) as a replacement for fish meal (FM) for Nile tilapia Oreochromis niloticus fry, initial average weight 1.9±0.18 g. FM (50% of the diet) was used as sole sources of animal protein in the control diet 1. The replacement levels of BBM in diets (2–5) were 25%, 50%, 75% and 100% of the FM. Methionine (1%) and lysine (0.5%) were added to each diet except the control diet. Three groups of fish were fed each of five isonitrogenous (31.2% CP) and isocaloric (20.1 kJ g^?1), and performance was compared against a nutritionally balanced control diet at the end of the experiment. Nile tilapia fed the diet containing 50% BBM exhibited comparable growth with those fed the FM‐based control diet. Digestibility of protein, energy and lipid decreased with increasing levels of BBM above 50% of total replacement FM into the diet. Incorporation of BBM in the diets significantly affected the moisture, fat and energy of whole fish body. These results suggest that BBM can replace 50% of the FM in diet for Nile tilapia fry, without adverse effects on fish performance.     

Partial Replacement of Fish Meal by Fermented Soybean Meal in Diets for Black Sea Bream,Acanthopagrus schlegelii,Juveniles

The effect of fish meal (FM) substitution with fermented soybean meal (FSBM) in the diets of the carnivorous marine fish, black sea bream, Acanthopagrus schlegelii, was investigated. An 8‐wk feeding trial was conducted with black sea bream (11.82 ± 0.32 g; mean initial weight) in indoor flow‐through fiberglass tanks (25 fish per tank). Six isonitrogenous and isoenergetic diets were formulated, in which FM was replaced by FSBM at 0% (control diet), 10% (FSBM10), 20% (FSBM20), 30% (FSBM30), 40% (FSBM40), or 50% (FSBM50), respectively. Each diet was fed to triplicate groups of fish twice daily to apparent satiation. The results showed that there was no difference in survival of black sea bream during the feeding trial. Fish fed the FSBM10 or FSBM20 diet showed comparable growth performance compared with fish fed the control diet (P > 0.05), whereas more than 30% replacement of FM adversely affected weight gain and specific growth rate (P < 0.05). Feed intake was significantly lower for fish fed the FSBM50 diet compared with fish fed the control diet. Feed conversion ratio (FCR) tended to increase with increasing dietary FSBM with the poorest FCR observed for fish fed the FSBM50 diet. Protein efficiency ratio and protein productive values showed similar patterns. Apparent digestibility of nutrients significantly decreased with increasing dietary FSBM level. With the exception of protein content, no significant differences in whole body and dorsal muscle composition were observed in fish fed the various diets. Fish fed the FSBM50 diet had significantly lower intraperitoneal ratio than fish fed the control or FSBM10 diet. Hepatosomatic index and condition factor were unaffected by dietary treatments. This study showed that up to 20% of dietary FM protein could be replaced by FSBM protein in the diets of juvenile black sea bream.     

Replacement of fish meal with processed carinata (Brassica carinata) seed meal in low animal protein diets of rainbow trout (Oncorhynchus mykiss)

A 56‐day growth trial was conducted to determine the amount of fish meal (FM) in rainbow trout (Oncorhynchus mykiss) diets containing 200 g/kg FM as the sole animal protein source; that could be replaced with carinata (Brassica carinata) meal (CM) processed by aerobic conversion (AC, by fungi ssp.) followed by a single wash (ACCM). ACCM replaced 50, 100 and 150 g of FM. Replacement of ≥100 g of FM with ACCM, resulted in reduced (p < 0.01) growth, due to reduced dietary lysine and diet consumption (p < 0.01). Fulton's condition factor K decreased (p < 0.01) with increased FM replacement. FCR (p < 0.01) had an inverse relationship with diet consumption. The trend in FCR was similar to the trend in PER (p < 0.01). Apparent net protein utilization was lower (p < 0.01) for the highest FM replacement diet. There was no effect of FM replacement by ACCM on whole‐body composition or viscera, spleen and liver weights. However, visceral fat increased (p < 0.01) with increased feed consumption. There was no apparent effect of ACCM on hematocrit, haemoglobin or mean corpuscular haemoglobin contents. Results of this study indicate that replacement of ≥100 g of FM by ACCM in low FM/animal (200 g/kg) RBT diets may have been achieved if feed consumption and dietary lysine were similar.     

Replacement of fish meal with a mixture of different plant protein sources in juvenile Nile tilapia, Oreochromis niloticus (L.) diets

A plant protein mixture (PPM) was tested to replace fish meal (FM) in diets for juvenile Nile tilapia, Oreochromis niloticus. Fish averaging (±SD) 3.7±0.14 g were divided into 15 groups. Three groups were fed each of five isonitrogenous (33.6%) and isocaloric (4.7 kcal g^?1) diets replacing 0%, 25%, 50%, 75% and 100% of the FM protein with similar percentages of PPM (PPM0, PPM25, PPM50, PPM75 or PPM100 respectively). The PPM consisted of 25% soybean meal, 25% cottonseed meal, 25% sunflower meal and 25% linseed meal, and 0.5% of both methionine and lysine were added to each diet except for the control. After 16 weeks of feeding, the fish fed diets PPM75 and PPM100 exhibited growth performance not differing significantly from the fish fed control diet. PPM substitution of up to 75% of the FM protein did not result in differences in the apparent protein digestibility compared with the control, whereas in the PPM100 group digestibility was significantly lower than in the other groups, except for fish fed the PPM75 diet. The incorporation of PPM in diets did not significantly affect whole‐body dry matter, protein, fat or energy compared with the control. The cost–benefit analyses of the test diets indicated that the PPM diets were economically superior to FM. The protein from PPM can completely replace the FM protein in the diets for Nile tilapia, based on the results of this study.     

Effects of dietary fishmeal replacement with Spirulina platensis on the growth,feed utilization,digestion and physiological parameters in juvenile gibel carp (Carassis auratus gibelio var. CAS III)

A 60‐day growth experiment was conducted to investigate the effect of dietary replacement of fishmeal by Spirulina platensis on growth performance, digestion and physiological parameters in juvenile gibel carp (5.0 ± 1.0 g). Four diets were formulated to replace 0 (SP0), 50% (SP50), 75% (SP75) and 100% (SP100) of dietary fishmeal protein by S. platensis respectively. Other two diets based on SP100 were supplemented with 2% dicalcium phosphate (SP100 + P) or 0.28% coated lysine (SP100 + Lys). The results showed that no significant differences of specific growth rate (SGR), feed efficiency (FE), feeding rate (FR) and protein efficiency ratio (PER) were observed between SP0 group and the replacement groups (SP50, SP75 and SP100). FE and PER of fish‐fed SP100 + Lys diet were significantly higher than the fish‐fed SP100 diet (p < .05). Apparent digestibility coefficients (ADCs) of dry matter, protein, energy and phosphorus increased significantly with the increasing S. platensis inclusion. Meanwhile, fish from SP100 + P or SP100 + Lys group had higher ADCs of nutrients compared to the SP100 group (p < .05). Compared with SP0 diet, fish‐fed S. platensis diets had higher activities of plasma superoxide dismutase, hepatopancreas total antioxidant capacity, plasma alkaline phosphatase and plasma lysozyme, as well as the lower content of plasma malondialdehyde. The present results indicated that dietary fishmeal could be fully replaced by S. platensis without any negative effects on growth performance of gibel carp. Supplementation of lysine in the S. platensis replacement diet could further improve the feed utilization of gibel carp.