Evaluation of poultry by‐product meal as partial replacement of fish meal in practical diets for juvenile tench (Tinca tinca L.)

The aim of this study was to evaluate different replacement levels of fish meal (FM) by poultry by‐product meal (PBM) on survival, growth performance and body composition of juvenile tench (Tinca tinca). A 90‐day experiment was conducted with 5 month‐old juveniles (31.95 mm total length, 0.396 g weight). Eight practical diets (50% crude protein) differing in the level of replacement of FM protein by PMB protein were tested: 0% (control), 25%, 31%, 37%, 43%, 49%, 55% and 61% corresponding to 0, 184.8, 229.2, 273.5, 317.8, 362.1, 406.5 or 450.8 g PBM kg^?1 diet respectively. Significant differences were not found (P > 0.05) between 25% replacement of FM protein by PBM protein (184.8 g kg^?1 PBM in diet) and control diet. At higher replacement levels, fish had significantly lower growth, higher feed conversion ratio and lower protein productive value (P < 0.05). Fish with externally visible deformities ranged from 1.1% to 3.3%. The relation among amino acid profiles of the diets, body composition, growth performance of juveniles and amino acid requirements of other fish species is discussed. Up to 184.8 g PBM kg^?1 diet can be included in diets for juvenile tench without impairing growth performance.     

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.     

Effect of fishmeal replacement by poultry by‐product meal on growth performance,proximate composition,digestive enzyme activity,haematological parameters and gene expression of gilthead seabream (Sparus aurata)

Two feeding trials examined the replacement of fishmeal (FM) with poultry by‐product meal (PBM) in the diet of juvenile Sparus aurata. In Feeding trial I (100 days), three diets were formulated, where FM protein was replaced by 50% (PBM50) and 100% (PBM100) PBM, while in Feeding trial II (110 days), four diets were formulated using the same FM control diet, but FM was replaced at lower levels: 25% (PBM25), and 25% (PBM25 + ) and 50% (PBM50 + ) with the supplementation of lysine and methionine amino acids. PBM protein can successfully replace 50% of FM protein in the diet of S. aurata without adverse effects on survival, feed intake, growth performance and feed utilization, given that the diet is balanced with lysine and methionine. The proximate composition of body and muscle was unaffected by the diet, but the total FM replacement resulted in reduced lipid and energy contents in fish. A fifty per cent FM replacement by PBM did not affect haematological parameters indicating a good fish health. Similarities in trypsin and chymotrypsin activities with FM‐fed fish suggest a high digestibility of PBM. High dietary levels of PBM reduced the liver gene expression of GH/IGF axis and of cathepsin D suppressing fish growth and modulating the protein turnover.     

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

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

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.     

Optimizing dietary protein sources for Japanese sea bass (Lateolabrax japonicus) with an emphasis on using poultry by‐product meal to substitute fish meal

This study evaluated the potential of using poultry by‐product meal (PBM) to replace fish meal in diets for Japanese sea bass, Lateolabrax japonicus. Fish (initial body weight 8.5 g fish^?1) were fed six isoproteic and isoenergetic diets in which fish meal level was reduced from 400 g kg^?1 (diet C) to 320 (diet PM1), 240 (diet PM2), 160 (diet PM3), 80 (diet PM4) or 0 g kg^?1 (diet PM5), using PBM as the fish meal substitute. The weight gain (WG), specific growth rate, nitrogen retention efficiency, energy retention efficiency and retention efficiency of indispensable amino acids were higher in fish fed PM1, PM2, PM3 and PM4 diets than in fish fed diets C or PM5. The phosphorus retention efficiency was lower in fish fed PM3, PM4 and PM5 diets than in fish fed C, PM1 or PM2 diets. Fish fed diet PM5 had the highest feed conversion ratio, total nitrogen waste output (TNW) and total phosphorus waste output (TPW) among the treatments. No significant differences were found in the hepatosomatic index or body contents of moisture, lipid and ash among the treatments. Fish fed diet C had lower condition factor and viscerosomatic index than those of fish fed PM1, PM3, PM4 and PM5 diets. The results of this study indicate that using fish meal and PBM in combination as the dietary protein source produced more benefits in the growth and feed utilization of Japanese sea bass than did using fish meal or PBM alone as the dietary protein source. The dietary fish meal level for Japanese sea bass can be reduced to 80 g kg^?1 if PBM is used as a fish meal substitute.     

Evaluation of rendered animal protein ingredients for replacement of fish meal in practical diets for gibel carp,Carassius auratus gibelio (Bloch)

A 12‐week feeding trial was carried out in fibreglass tanks to examine partial replacement of fish meal (FM) with poultry by‐product meal (PBM), meat and bone meal (MBM) and blood meal (BM) in practical diets for gibel carp Carassius auratus gibelio (Bloch). Triplicate groups of fish (initial body weight 15.3 g fish^?1) were fed eight isonitrogenous (crude protein: 37.5%) and isolipidic diets (crude lipid: 7%). The control diet is the commercial diet of gibel carp, which used 18% of FM as the sole animal protein source. In the other seven diets (Diet 2–Diet 8), 17–83% of FM protein was substituted by a blend of PBM and BM or a blend of PBM, MBM and BM. The final body weight and thermal‐unit growth coefficient of fish fed the feeds in Diet 8 in which 83% of FM protein was replaced by the blend of 3% BM, 10% PBM and 5% MBM is significantly lower than Diet 1 (the control). The feed efficiency ratio in Diet 8 group is significantly lower than Diet 1, 2, 4 and 7 groups. The results of the present study indicated that a combination of PBM, BM and MBM can replace most of the FM protein and the FM level can be reduced to about 6% with satisfactory growth and feed utilization in practical diets for gibel carp.     

The effect of substituting fishmeal with poultry by‐product meal in diets for Totoaba macdonaldi juveniles

Four diets were formulated to evaluate the partial to total substitution of fishmeal with poultry by‐product meal (PBM) (0, 33, 67 and 100PBM) in diets for totoaba juveniles (Totoaba macdonaldi). Amino acid profiles from diets and fatty acid content in diets and muscle tissue were used to assess the fish performance using PBM as fishmeal replacement. Stable isotopes of nitrogen (δ¹⁵N) were measured in muscle and liver tissue to quantify the retention of each protein source. At the end of the experimental period, the fish fed the 67PBM diet had a significantly higher growth gain increase compared to the other treatments (almost 2000% over an 86 days period; TGC of 1.06). The total replacement of fishmeal with PBM led to low growth gain increase (ca. 220% over 72 days; TGC of 0.52) and increased mortality. Both fish performance and tissues' fatty acid composition suggest that the 100PBM diet was deficient in essential fatty acids. An isotope‐mixing model applied to isotope ratios of muscle and liver tissues of fish fed the 67PBM tissues indicated that PBM was retained into muscle and liver tissue in a higher proportion than its level of inclusion in the diet. We conclude that PBM is a good source of nutrients for totoaba juveniles when used in up to 67% fishmeal replacement level in diets containing 52% protein leading to adequate growth rate and survival.     

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.     

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).     

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).     

Fish meal replacement with solvent‐extracted soybean meal or soy protein isolate in a practical diet formulation for Florida pompano (Trachinotus carolinus,L.) reared in low salinity

Two 8‐week growth trials were conducted with juvenile Florida pompano, Trachinotus carolinus fed 0–1000 g kg^?1 replacement of fish meal (FM) protein with soybean meal (SBM) or soy protein isolate (SPI). Practical‐type diets were formulated with at least 360 g kg^?1 digestible protein and 24 mg kJ^?1 digestible protein/digestible energy. Weight gain and efficiency were not different between 0 and 800 g kg^?1 FM protein replacement with SBM. Regression of weight gain and protein productive value suggested a conservative level of SBM substitution was 380 g kg^?1 FM protein. It appeared that lysine could be limiting beyond 400 g kg^?1 FM replacement. No significant differences were detected in fish fed 0 and 200 g kg^?1 FM protein replacement with SPI. A decrease in weight gain and efficiency parameters occurred at 400 g kg^?1 protein replacement, and fish fed a replacement of 600 g kg^?1 or greater with SPI exhibited signs of starvation. A third trial indicated intake and growth were significantly reduced (P < 0.0001) in fish fed 600 g kg^?1 relative to 0 g kg^?1 FM protein replacement with SPI. Poor palatability of diets containing 400 g kg^?1 or more FM protein replacement with SPI appeared to be the causative factor for poor performance.     

The potential of pet‐grade poultry by‐product meal to replace fish meal in the diet of the juvenile spotted rose snapper Lutjanus guttatus (Steindachner, 1869)

A 12‐week feeding trial was conducted to examine the replacement of fish meal with pet‐grade poultry by‐product meal (PBM‐PG) in the spotted rose snapper Lutjanus guttatus diet. Five experimental diets were formulated to contain graded levels of PBM‐PG at proportion of 250, 500, 75 or 900 g kg^?1. The control diet contained sardine fish meal as the main protein source. Four groups of 15 randomly assigned L. guttatus juveniles were fed to satiation 3 times day^?1. Except for the fish fed the PBM‐PG90 diet, the growth performance, survival and feed utilization efficiency of the experimental fish were not significantly lower than those of the control fish. The dietary level of PBM‐PG did significantly affect the haematological characteristics (P < 0.05). The dietary dry matter and protein apparent digestibility coefficients (ADCs) decreased with increasing dietary PBM‐PG. High values for lipid ADCs were observed in all diets, with significant differences among the dietary treatments. The fish whole‐body protein, moisture, lipid and ash contents were not affected by the inclusion of dietary PBM. These results indicate that high‐quality terrestrial PBM can successfully replace more than half of the marine fish meal protein in the L. guttatus diet.     

Use of turkey meal as partial and total replacement of fish meal in practical diets for sunshine bass (Morone chrysops × Morone saxatilis) grown in tanks

Economical, nutritious diets for hybrid striped bass (HSTB) are required for the continued expansion and sustainability of this industry. Turkey meal (TM) is a by‐product of the US turkey industry and is a potentially‐valuable local, alternative protein source for use in aquaculture diets because of its excellent nutritional composition and quality. TM may substitute for more expensive fish meal (FM)‐based diets; however, there are no published data with regard to using this ingredient in sunshine bass diets. Therefore, a 16‐week feeding trial was conducted with juvenile (36 g) sunshine bass (Morone chrysops × Morone saxatilis) to evaluate growth, feed conversion and body composition when fed diets with decreasing levels of FM (300, 200, 100 and 0 g kg^?1) and increasing levels of turkey meal (0, 97, 175 and 264 g kg^?1). Four practical diets were formulated to contain 400 g kg^?1 protein and similar energy levels. Twenty fish were stocked into each of the 12, 1200‐L circular tanks and were fed twice daily ad libitum. At the conclusion of the feeding trial, there were no significant (P > 0.05) differences in final mean weight, percentage weight gain, specific growth rate and feed conversion ratio among treatments, which averaged 363.7 g, 904.3%, 2.02% day^?1 and 1.73, respectively. Percentage survival of fish fed diet 4 (0 g kg^?1 FM and 264 g kg^?1 TM) was significantly (P > 0.05) lower (survival = 88.3%) than fish fed diet 3 (100 g kg^?1 FM and 175 g kg^?1 TM; survival = 95%), but not different from fish fed diet 1 (survival = 92.5%) and fish fed diet 2 (survival = 93.3%). Fillet weight and amount of abdominal fat were not significantly different among all treatments and averaged 258 and 58 g kg^?1, respectively. Fish fed diet 1 (300 g kg^?1 FM, 0 g kg^?1 TM) and diet 2 (200 g kg^?1 FM and 970 g kg^?1 TM) had a significantly (P < 0.05) lower hepatosomatic index (2.83 and 3.01, respectively) than fish fed diet 4 (3.33), but not different (P > 0.05) compared to fish fed diet 3 (3.14). Lipid in the fillet of fish fed diet 2 (197 g kg^?1) was significantly (P < 0.05) higher than fish fed all other diets; and the percentage lipid in the fillet of fish fed diet 1 (126 g kg^?1) was significantly lower than fish fed diets 2 and 4, but not different (P >0.05) compared to fish fed diet 3. Fillet moisture, protein and ash were similar among fish fed all diets and averaged 748, 798 g kg^?1 and 51.0 g kg^?1 (dry‐matter basis), respectively. The amino acid composition of fillets was similar among all treatments with a few slight significant differences. Results from the present study indicate that tank‐grown sunshine bass can be fed a diet containing 264 g kg^?1 TM with 0 g kg^?1 FM, compared to diets containing up to 300 g kg^?1 FM, without adverse effects on weight gain, growth rate, feed conversion and body composition. Further research should be conducted using lower‐protein diets to determine minimum protein level for tank‐grown sunshine bass.     

Supplementations of poultry by‐product meal and selenium yeast increase fish meal replacement by soybean meal in golden pompano (Trachinotus ovatus) diet

The effects of poultry by‐product meal (PBM) and selenium yeast (Se‐yeast) supplementations on fish meal replacement by soybean meal (SBM) in the diet of golden pompano (Trachinotus ovatus) were examined. In trial I, a 2 × 3 layout including two PBM levels (100 and 170 g kg^?1) and three levels of fish meal replacement (0, 40 or 60%) was used. At 100 g kg^?1 PBM, fish fed the basal diet exhibited the highest weight gain (WG) and nitrogen retention efficiency (NRE) and the lowest feed conversion ratio (FCR). At 170 g kg^?1 PBM, no significant differences were found in WG and NRE between fish fed the basal diet and diet with 40% of fish meal replaced by SBM. In trial II, the basal diet containing 170 g kg^?1 PBM (trial I) served as a reference. A 2 × 2 layout included two levels of fish meal replacement (40 or 60%) and two levels of Se‐yeast addition (0 and 1 g kg^?1). No significant differences were found in WG, feed intake, FCR and NRE between fish fed the reference diet and diet with 40 or 60% fish meal replacement plus 1 g kg^?1 Se‐yeast addition. This study indicates that supplementations of PBM and Se‐yeast can enhance the level of fish meal replacement by SBM in golden pompano diet. Dietary fish meal level can be reduced to 140 g kg^?1 by optimizing inclusion of SBM, PBM and Se‐yeast.     

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

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

Use of cottonseed meal supplemented with iron for detoxification of gossypol as a total replacement of fish meal in Nile tilapia, Oreochromis niloticus (L.) diets

The objective of this study was to determine the effect of total replacement of fish meal by cottonseed meal (CSM) supplemented with various levels of iron in practical diets on growth performance, feed utilization, body composition and some biological and haematological parameters of Nile tilapia, Oreochromis niloticus (L.). Juvenile fish (average weight 3.78±0.1 g) were stocked in 18 glass aquariums (80 L each) at 25 fish per aquarium. Fish meal (50% of the diet) was used as the sole source of animal protein in the control diet 1. Diets 2–6 had 100% CSM (0.145% free gossypol) protein with various levels of supplemented iron (86, 486, 972, 1458 and 1944 mg Fe kg diet^?1) in diets 2–6 respectively. Diets were fed to fish twice daily at a rate of 3% of body weight during the first 12 weeks then 2% of the total fish biomass daily until the end of the experiment (30 weeks). The results of this study revealed that, groups of fish fed diets 1, 4, 5 and 6 had significantly (P≤0.01) the higher average body weight and specific growth rate than those of fish fed diet 2 (100% CSM without iron supplementation) and diet 3 (100% CSM plus 486 mg Fe kg diet^?1). The best values for feed conversion ratio, protein efficiency ratio and condition factor (K) were recorded with groups of fish fed diet 4 (100% CSM plus 972 mg Fe kg diet^?1). Red blood cell count, haematocrit and haemoglobin were increased with increasing levels of iron and significantly affected by dietary iron. Hepatosomatic index for diets 3–6 were not significantly different (P>0.05) and superior to that of diet 1 control [100% fish meal (FM)]. The gonadosomatic index of males of Nile tilapia was not influenced by CSM diets with or without iron, while females of Nile tilapia were significantly influenced with iron and the lowest values were recorded with groups of fish fed diet 2 (100% CSM without iron supplementation). Apparent digestibility coefficients of protein, fat dry matter and energy were relatively high for most diets supplemented with iron and increased by increasing iron supplementation. There were no significant differences between groups of fish fed diet 1 (100% FM) and diets 5 and 6 which contained 100% CSM with additional 1458 and 1944 mg Fe kg diet supplemental iron^?1 respectively. Proximate composition of whole body was not influenced by diet. Adding 972 mg Fe kg diet^?1 from ferrous sulphate to the CSM‐based diets that contained 972 mg free gossypol (1:1 iron to free gossypol ratio) for Nile tilapia reduce the negative effects of gossypol and improved growth performance, feed utilization and blood parameters and can totally replace fish meal in tilapia diets.     

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.     

Incorporation of a mixture of meat and bone meal,poultry by‐product meal,blood meal and corn gluten meal as a replacement for fish meal in practical diets of Pacific white shrimp Litopenaeus vannamei at two dietary protein levels

A 6‐week feeding trial was carried out in glass tanks to determine the effects of partial replacement of fish meal (FM) with a combination of meat and bone meal (MBM), poultry by‐product meal (PBM), blood meal (BM) and corn gluten meal (CGM) in practical diets on the growth, nutrient digestibility and body composition of Pacific white shrimp. Six practical diets were formulated, containing two levels of crude protein (CP) (330 and 380 g kg^?1) and similar crude lipid (CL) levels. For the 330 g kg^?1 dietary protein level, 0, 357 and 714 g kg^?1 FM were replaced by the mixture in Diets 1–3, respectively; while 0, 514 and 784 g kg^?1 FM were replaced in Diets 4–6, respectively, for 380 g kg^?1 dietary protein level. White shrimp‐fed diets containing 330 g kg^?1 CP had significantly lower weight gain compared with white shrimp fed diets containing 380 g kg^?1 CP. Increasing the mixture and dietary protein level significantly raised the body ash content of white shrimp. White shrimp fed a low‐protein diet obtained better nutrient digestibility compared with those fed a high‐protein diet.     

Effect of using okara meal,a by‐product from soymilk production as a dietary protein source for Nile tilapia (Oreochromis niloticus L.) mono‐sex males

The main objectives of this study was to evaluate the effect of partial and total replacement of fishmeal protein by okara meal (OM) protein in practical diets on growth performance, feed utilization and body composition of Nile tilapia (Oreochromis niloticus L.) mono‐sex males. Fish of an average initial weight of 2.67 ± 0.01 g were stocked in 15 glass aquariums (80 L each) at a rate of 15 fish per aquarium. Fishmeal protein (18% of the diet) was used as the sole source of animal protein in the control diet. Percent replacement of fish meal (FM) by OM on the basis of crude protein was 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 5%, and then gradually reduced to 4% of the total fish biomass daily, for a period of 12 weeks. The results revealed that the fish fed diets A (100% FM control), B (25% OM), C (50% OM) and D (75% OM) had significantly the best average body weight, weight gain g, specific growth rate (SGR % day^?1), weight gain % and feed intake g fish^?1 compared with diet E (100% OM) which had the lowest values. There were no significant differences (P > 0.05) among all experimental diets and control in terms of feed conversion ratio (FCR), protein efficiency ratio (PER) and survival rate %. Whole body protein contents for fish fed diets B, C and D were superior to the control diet. Incorporation of OM in the diets increased significantly whole body fat content. Incorporation of OM in the diets significantly increased apparent digestibility coefficient of crude protein crude fat and energy. Therefore, these findings suggest that up to 75% of FM protein can be replaced by OM protein in Nile tilapia, mono‐sex male diets.