Crude protein in low‐fish meal diets for juvenile Litopenaeus vannamei can be reduced through a well‐balanced supplementation of essential amino acids

The use of supplemental essential amino acids (EAAs) has been shown to provide an opportunity to minimize excess levels of crude protein (CP) in animal feeds. The present study investigated the effect of reducing the amount of CP in low‐fish meal diets (5%) for juvenile Litopenaeus vannamei. Four sets of diets were prepared containing (% on a fed basis, mean ± SD) 31.24 ± 0.71, 33.70 ± 0.41, 36.90 ± 0.44, and 39.63 ± 0.14% CP, with each protein level containing a total dietary methionine (Met) (Met + Cys) level of 0.56 ± 0.02 (1.07 ± 0.23), 0.71 ± 0.01 (1.22 ± 0.20), 0.88 ± 0.02 (1.38 ± 0.22), or 1.04 ± 0.02% (1.55 ± 0.18%). Shrimp of 1.00 ± 0.08 g were stocked in 84 outdoor tanks of 1 m³ at a rate of 100 shrimp/m² and raised for 75 days. Final survival ranged from 83 to 97% and was unaffected by Met content. Both survival and yield were significantly depressed when shrimp were fed the 31% CP diet. Shrimp grew at a weekly rate of between 0.79 and 0.97 g, achieving a final body weight (BW) in excess of 10.8 g. There was a significant interaction between CP and Met over BW. Shrimp fed 0.56% Met achieved the lowest BW at harvest. Increasing CP beyond 34% did not enhance BW. With a dietary Met content of 0.71%, the highest BW was achieved with 34% CP compared to other levels. There was a significant improvement in Feed Conversion Ratio (FCR) when CP was raised from 31 to 34%. Similarly, dietary Met levels above 0.71% resulted in a significantly better FCR compared to 0.56%. Our study has shown that, if dietary Met (Met + Cys) meets a minimum of 0.71% (1.22%), levels of CP could be reduced from 40 to 34% without adverse effects on shrimp performance.     

The evaluation of practical diets on a basis of digestible crude protein,lysine and methionine for Litopenaeus vannamei

A feeding trial was conducted to evaluate the efficacy of replacing fish meal (FM) with blood meal (BM), poultry by‐product meal (PBM), meat and bone meal (MBM) and shrimp head meal (SHM), rapeseed meal (RM) and peanut meal (PM) on a digestible basis of crude protein and lysine and methionine in five practical diets for the Pacific white shrimp at the FM levels of 300, 250, 200, 150 and 100 g kg^?1 under laboratory conditions. Each of the five experimental diets was hand‐fed to four replicate tanks of shrimp with an average weight of 0.33 ± 0.03 g to satiation at each meal. The shrimp were fed three times a day over a six‐week period. The per cent weight gain of initial body weight (WG%) was significantly lower in shrimp fed 100 g kg^?1 FM diet, but the value for hepatosomatic index (HSI) and the level of blood urea nitrogen (BUN) tended to be higher in shrimp fed 100 g kg^?1 FM diet than those in shrimp fed other diets. The lowest value for feeding rate (FR) occurred for shrimp fed the basal diet and was significantly lower than that in shrimp fed the FM diets at 100–150 g kg^?1. Shrimp fed diets containing 200 g kg^?1 or lower FM had significantly lower feed utilization than those fed the 250 g kg^?1 FM diet and the basal diet. The protein efficiency ratio (PER) in the shrimp fed the basal diet was significantly higher than in the other FM diets. Decreasing the FM replacement level significantly reduced nutrient digestibility except in the cases of ash and gross energy, but it did not affect the survival, condition factor (CF), body composition, digestive enzyme activity or plasma transaminase activity. The results of the study indicate that feeding a diet formulated on a digestible basis and involving FM replacement with other protein sources at a greater replacement proportion will not produce a level of shrimp growth equal to that achieved by feeding the basal diet.     

Spirulina meal has acted as a strong feeding attractant for Litopenaeus vannamei at a very low dietary inclusion level

The present work aimed at studying the growth performance and feeding preference of Litopenaeus vannamei juveniles fed on diets supplemented or not with Spirulina meal. Litopenaeus vannamei juveniles (3.89 ± 0.25 g) were stocked for 72 days in 28 round 500‐L tanks at 44 shrimp/tank (77 juveniles/m²). The diets were supplemented with 0.5% of a commercial feed attractant (C25 and C50) or with Spirulina meal (S25 and S50). In C25/S25 and C50/S50 there were reductions of 25% and 50% in fishmeal inclusion level respectively. In a further study, two feeding trays with different diets were allowed to shrimp at the same moment and they were located in opposite walls of the tank. The feed remains in each feeding tray were collected and weighted to calculate the dry feed remains. The weekly growth rate of shrimp fed on S25 (0.89 ± 0.03 g) was not significantly different from those fed on C25 (0.89 ± 0.01 g). The attractiveness experiment showed that S25 was preferred significantly more by shrimp than C25. In conclusion, Spirulina meal added at 0.5% in a complete diet for L. vannamei juveniles, with 14% of Peruvian fishmeal, has proved itself as a nutritionally efficient feeding attractant.     

Supplementation with 2‐hydroxy‐4‐(methylthio)butanoic acid (HMTBa) in low fish meal diets for the white shrimp,Litopenaeus vannamei

This work evaluated the performance of Litopenaeus vannamei to low fish meal diets supplemented with 2‐hydroxy‐4‐(methylthio)butanoic acid (HMTBa). A basal diet with 150.0 g kg^?1 of anchovy fish meal was designed. Two positive control diets were formulated to reduce fish meal at 50% and 100% with 1.0 and 2.0 g kg^?1 of MERA? Met_Ca (calcium salt with 84% HMTBa activity), respectively. Two nearly equivalent diets acted as negative controls, without HMTBa supplementation. A total of 50 clear‐water tanks of 500 L were stocked with 2.22 ± 0.19 g shrimp under 70 animals m^?2. Shrimp survival (92.3 ± 5.1% and 81.4 ± 8.0%), yield (808 ± 12 and 946 ± 17 g m^?2) and FCR (2.17 ± 0.19 and 3.12 ± 0.37) showed no differences among diets after 72 or 96 days, respectively. A significantly higher shrimp body weight and weekly growth were observed for those fed with the basal diet or diets supplemented with HMTBa compared with non‐supplemented ones. This study has shown that L. vannamei growth, body weight, survival, yield and FCR were supported by HMTBa supplementation when 150.0 g kg^?1 of fish meal was replaced by soybean meal and other ingredients, at 50% and 100%.     

Effect of replacing fishmeal with canola meal on growth and nutrient utilization in kuruma shrimp Marsupenaeus japonicus (Bate)

A feeding trial was conducted to assess the nutritional values of canola meal as a substitute for fishmeal in diets for kuruma shrimp using five isocaloric diets (190 kJ kg^?1) prepared by replacing 0%, 10%, 20%, 30% and 40% of fishmeal protein with canola meal protein in CM0, CM10, CM20, CM30 and CM40 diets respectively. Triplicate groups of juveniles (0.19 g) were fed the respective diets for 60 days in tanks. At the end of trial, weight gain (%) and specific growth rate (% day^?1) were not significantly (P > 0.05) different among shrimp fed CM0, CM10 and CM20 diets. However, growth was significantly (P < 0.05) decreased in shrimp fed CM30 and CM40 diets. As with growth performance, feed intake, feed conversion ratio and protein efficiency ratio were also decreased (P < 0.05) in CM30 and CM40 groups. Whole body dry matter, methionine and proline were significantly decreased with canola meal substitution levels. In general, retention efficiency of protein and indispensible amino acids were decreased as canola meal increased in diets. It may be concluded that 20% fishmeal protein can be successfully replaced with canola meal, while supplementation of amino acids or blending with complementary proteins could facilitate higher fishmeal replacements in kuruma shrimp diets.     

Availability of essential amino acids,nutrient utilisation and growth in juvenile black tiger shrimp,Penaeus monodon,following fishmeal replacement by plant protein

Two trials with juvenile black tiger shrimp (Penaeus monodon) were undertaken to study the effects of replacing fishmeal by different levels of plant proteins on growth performances and nutrient utilisation of shrimp in semi-intensive conditions (Expt. 1) and on the availability of dietary nitrogen (N) and amino acids (Expt. 2). Five isoproteic diets (on crude protein basis) were formulated to contain 34, 24, 16, 8, or 0% fishmeal, with fishmeal being replaced by a mixture of plant protein (corn gluten meal, wheat gluten, and rapeseed meal). In Expt. 1, the shrimp (initial body weight, IBW 1.5 ± 0.1 g) were reared in earthen ponds for 144 days and fed one of the experimental diets. Apparent digestibility of nutrients and AA were assessed in Expt. 2, using 150 L tanks and shrimp of 12.8 ± 0.4 g IBW. After 144 days in grow-out ponds, shrimp fed the diet with 24% of fishmeal had similar growth as those fed the control diet containing 34% fishmeal (0% replacement). When 50% or more of the fishmeal were replaced, weight gain as well as N and energy gains significantly decreased. Digestibility of dry matter, protein and energy was also significantly lower in all fishmeal-replaced diets. In particular, leucine digestibility decreased by 26% at 100% replacement, which was significantly correlated to an increased incorporation of corn gluten meal. Our data confirm the need to improve our knowledge on AA availability and raw material quality in order to improve fishmeal replacement in P. monodon diets.     

Lupin kernel meal as fishmeal replacement in formulated feeds for the Whiteleg Shrimp (Litopenaeus vannamei)

Rapidly expanding global aquaculture requires sustainable, local protein sources to supplement the use of fishmeal. Lupin seed meal (Lupinus angustifolius) was tested as sustainable diet component for Whiteleg shrimp (Litopenaeus vannamei). Controlled feeding experiments were conducted in a recirculating aquaculture system for eight weeks. Juvenile shrimps were provided formulated diets containing various levels of lupin meal inclusion (0, 100, 200 and 300 g kg^?1) supplementing the fishmeal component, and a commercial feed as general reference. Shrimp survival, growth, metabolic and immune parameters were analysed. Survival did not differ significantly between groups. Growth performance was significantly impaired in shrimp fed diets containing more than 100 g kg^?1 lupin meal. Lupin meal supplementation did not affect haemolymph protein content, whereas glucose and acylglyceride concentrations varied between treatments and were highest in animals fed the 100 g kg^?1 lupin meal diet. Phenoloxidase activity was highest in shrimp fed 100 g kg^?1 lupin meal diet indicating improved immune status. The present study indicates that low inclusion levels of lupin meal do not cause adverse effects and seem to stimulate the immune system of juvenile L. vannamei.     

Evaluation of potential of lupin meal as an alternative to fish meal in juvenile Penaeus monodon diets

An indoor feeding trial in a flow-through marine water system was performed to evaluate the feasibility of using dehulled lupin Lupinus albus seed meal as a protein source to replace fish meal in diets for the juvenile Penaeus monodon. Five isonitrogenous (40% crude protein) diets formulated by replacing 0, 25, 50, 75, and 100% of fish meal protein by lupin meal protein were fed to shrimp (mean initial weight of 4.32 ± 0.23 g) three times daily at a feeding allowance of 5% body weight per day for 42 days. Shrimp fed diets with 0, 25, 50 and 75% replacement had similar (P > 0.05) weight gain, dry matter feed intake, feed conversion ratio (FCR), protein efficiency ratio (PER), and apparent net protein utilization (ANPU). Shrimp fed the highest dietary inclusion level of lupin meal (100% replacement) had significantly (P < 0.05) lower responses for all the above parameters than shrimp fed all other diets. Survival was high (87–100%) and similar for all diets. Apparent dry matter digestibility (ADMD) of diets with 25, 50, 75 and 100% replacement of fish meal with lupin meal was similar (75.6–76.6%) and significantly (P < 0.05) higher than that of diet with 0% replacement (73.9%). Diets containing the two highest lupin inclusion levels (75 and 100% replacement) had significantly (P < 0.05) better apparent protein digestibility (APD) than those containing the two lowest lupin meal inclusion levels (0 and 25% replacement). There were no significant differences (P > 0.05) in whole-body composition (dry matter, protein, lipid and ash) of shrimp fed on the various diets. Pellet water stability was inversely related to level of lupin meal inclusion. It was found, in this study, that up to 75% protein of fish meal can be replaced with the protein of dehulled lupin seed meal in diets for juvenile P. monodon. The diet with total replacement of fish meal containing 40% lupin meal was utilized very poorly by the shrimp.     

Comparative nutritional evaluation of raw, methanol extracted residues and methanol extracts of moringa (Moringa oleifera Lam.) leaves on growth performance and feed utilization in Nile tilapia (Oreochromis niloticus L.)

The suitability of raw and methanol‐extracted moringa (Moringa oleifera Lam.) leaf meal to replace 10%, 20% and 30% of the total fishmeal‐based dietary protein in tilapia feeds was tested. Ten isonitrogenous and isocalorific feeds (35% crude protein and 20 MJ kg^?1 gross energy), denoted as diets 1 (fishmeal‐based control), 2, 3, 4 (containing 13%, 27% and 40% raw moringa leaf meal), 5, 6, 7 (containing 11%, 22% and 33% methanol‐extracted moringa leaf meal), and 8, 9, 10 (containing methanol‐soluble extracts of the raw moringa leaf meal at the same level as would have been present in diets 2, 3, 4) were prepared. Forty tilapia (16.7±2.4 g), kept individually, were fed the experimental diets (four fish per treatment) at the rate of 15 g feed per kg metabolic body weight (kg^0.8) per day. A reduction in the growth performance was observed with an increasing level of raw moringa leaf meal (diets 2–4), whereas inclusion of methanol‐extracted leaf meal (diets 5–7) had no significant (P<0.05) effect on the growth performance compared with the control (diet 1). The growth performance of fish fed diets 8–10 containing methanol extracts of the moringa leaf meal were also similar to the control. The chemical composition values of the gained weight showed that lipid accretion decreased with increased inclusion of moringa leaves, and ash content increased. Dietary moringa methanol extracts reduced protein accretion, but had no effects on lipid and ash contents compared with the control. The inclusion of raw, methanol‐extracted residues and methanol extracts of the moringa leaf meal (diets 3 and 4, 5, 6 and 7, and 8 respectively) reduced the plasma cholesterol content significantly. Similarly, a significant reduction in muscle cholesterol was observed in fish fed the diets 4, 8, 9 and 10. It was concluded that the solvent‐extracted moringa leaf meal could replace about 30% of fishmeal from Nile tilapia diets.     

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

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

Evaluation of amaranth (Amaranthus caudatus L.) and quinoa (Chenopodium quinoa) protein sources as partial substitutes for fish meal in Litopenaeus vannamei grow‐out diets

Two groups of isonitrogenous diets formulated by replacing 15%, 25%, 35% and 45% of fish meal protein by amaranth meal and quinoa meal were used to evaluate the performance of Litopenaeus vannamei. Growth showed significant reduction (P < 0.05) in the group of shrimp fed with amaranth diets, with diet A15 showing the best specific growth rate (SGR = 2.81% day^?1), but after the control diet AQ0 (3.07% day^?1). Diet A15 had significantly (P < 0.05) the best digestibility of dry matter (79.7%) and protein (88.4%) without differences compared to control diet AQ0 (75.1% and 85.2%). Replacement with quinoa meal at any level tested did not significantly affect (P > 0.05) the shrimp growth performance. Shrimp fed with quinoa diets showed better SGR (3.05% day^?1) than those shrimp fed with amaranth (2.56% day^?1). No differences in feed conversion ratio appeared in either of the protein sources, but quinoa diets presented a better average (3.13) than amaranth diets (4.01). The apparent digestibility of dry matter and protein for quinoa diets was similar for all diets, but they were statistically different (P < 0.05) from the control diet. We conclude that quinoa meal can replace fishmeal up to 45%, whereas it can be replaced with amaranth meal up to 15%, without adverse effects on growth and survival.     

Effect of replacing fishmeal and oil with simple or complex mixtures of vegetable ingredients in diets fed to Nile tilapia (Oreochromis niloticus)

The effect of replacing fishmeal with simple or complex mixtures of plant proteins in tilapia diets was examined. Diet formulations were arranged in a 2 × 4 factorial design with two types of plant protein mixtures used to replace fishmeal (simple: soybean meal and maize gluten meal or complex: soybean meal, maize gluten meal, dehulled flax, pea protein concentrate and canola protein concentrate) and four levels of protein originating from fishmeal (1000 g kg^?1, 670 g kg^?1, 330 g kg^?1 and 0 g kg^?1). Diets contained equal digestible protein (380 g kg^?1) and digestible energy (17.6 MJ kg^?1). The average daily gains, specific growth rates and feed efficiencies of fish fed diets with 0 g kg^?1 fishmeal were significantly lower than fish fed diets with the 330 g kg^?1, 670 g kg^?1 or 1000 g kg^?1 fishmeal levels. Fish fed the complex diets had significantly higher average daily gains, specific growth rates, feed : gain ratios and protein efficiency ratios than those fed the simple diets. Intestinal villus length decreased with decreasing levels of fishmeal and increased with increased diet complexity but the effects were not significant. Replacement of fishmeal with a complex mixture of plant ingredients may allow a greater replacement of fishmeal in diets fed to Nile tilapia.     

The effect of dietary taurine supplementation on growth performance,feed utilization and taurine contents in tissues of juvenile white shrimp (Litopenaeus vannamei,Boone, 1931) fed with low‐fishmeal diets

An 8‐week feeding trial was conducted to investigate the effects of different taurine levels on the growth performance of juvenile white shrimp fed with low‐fishmeal diets. Six level diets of dietary taurine were prepared by the supplementation of taurine (0, 0.4 g kg^?1, 0.8 g kg^?1, 1.2 g kg^?1, 2.0 g kg^?1 and 4.0 g kg^?1) to a control diet (100 g kg^?1 fish meal). Each diet was randomly assigned to triplicate groups of 30 shrimps (0.48 ± 0.0 g), each three times daily. Shrimp fed the 0.4 g kg^?1 and 0.8 g kg^?1 taurine‐supplemented diets, showed significantly higher weight gain, protein efficiency ratio and protein retention efficiency than those of shrimp fed the other diets. The quadratic regression analysis (y = ?55.59x² + 187.1x + 750.2 R² = 0.587) indicated that a maximum weight gain occurring at 1.68 g kg^?1 of taurine level. The whole body and hepatopancreas taurine contents of the taurine‐supplemented diets were on the same level and higher than those of the control group. Total free amino acid content in the hepatopancreas was significantly affected by taurine supplementation. The results of the present study demonstrate that the white shrimps require taurine as an essential nutrient for growth performance.     

Substitution of fishmeal with soybean meal in practical diets for juvenile white shrimp Litopenaeus schmitti (Pérez‐Farfante & Kensley 1997)

The feasibility of substituting soybean meal for fishmeal diets for juvenile white shrimp Litopenaeus schmitti (0.35±0.01 g) was evaluated, and an adequate substitution level was determined. Five diets were evaluated using 46%, 59%, 75%, 88% and 100% substitution levels. Pellet water stability was significantly affected by dietary soybean content (P<0.05). Increased soybean content produced lower pellet stability, ranging from a dry matter loss of 14–22% after a 2‐h immersion, and 20–33% after an 8‐h immersion. After 52 days, significant differences (P<0.05) were found in shrimp weight, feed conversion ratio and protein efficiency ratio. The values were 0.64–1.06 g, 2.8–7.9 and 0.45–1.21, respectively, for the three measurements. Overall, better results were obtained with diets where soybean meal was substituted for fishmeal up to 75%. The 100% soybean meal diet resulted in poor growth performance of shrimp. Survival rates were acceptable for all treatments (90% or higher) and no significant differences were found in survival between treatments. Regression analysis using the broken‐line methodology indicated that 76.5±2% is an optimum soybean substitution level in diets that contained fishmeal and soybean as the major protein sources for grow‐out of juvenile white shrimp.     

Effect of fishmeal substitution with various animal and/or plant protein sources in the diet of the abalone Haliotis discus hannai Ino

The effect of dietary substitution of animal and/or plant protein sources for fishmeal on the growth and body composition of juvenile abalone was determined. Nine experimental diets in triplicate were prepared: Con, SM, PM, CM, SPM, MB, SM+CM, SM+SPM and CM+SPM diets. A 350 g kg^?1 fishmeal was included in the Con diet, and the whole fishmeal was substituted with a 580 g kg^?1 soybean meal (SM), 335 g kg^?1 poultry meal (PM), 370 g kg^?1 corn gluten meal (CM), 325 g kg^?1 silkworm pupae meal dehydrated (SPM), 590 g kg^?1 meat and bone meal (MB), the combined 290 g kg^?1 soybean meal and 180 g kg^?1 corn gluten meal (SM+CM), 290 g kg^?1 soybean meal and 160 g kg^?1 silkworm pupae meal dehydrated (SM+SPM) and 180 g kg^?1 corn gluten meal and 170 g kg^?1 silkworm pupae meal dehydrated (CM+SPM) diets respectively. All experimental diets were iso‐nitronic and iso‐lipidic. The survival of abalone fed with the SM and SM+SPM diets was higher than that of abalone fed with the CM, SPM, MB and CM+SPM diets. Weight gain of abalone fed with the SM+SPM diet was higher than that of abalone fed with all the other experimental diets, except for that of abalone fed with the SM+CM diet. The combined soybean meal and corn gluten meal (SM+CM) or silkworm pupae meal (SM+SPM) could be replaced with the whole fishmeal in the diet for abalone and improved its performance.     

Inclusion of rendered animal ingredients as fishmeal substitutes in practical diets for cuneate drum, Nibea miichthioides (Chu, Lo et Wu)

Potential of using rendered animal ingredients, poultry by‐product meal (PM), meat and bone meal (MBM), feather meal (FM) and blood meal (BM) to replace fishmeal in practical diets for cuneate drum Nibea miichthioides (Chu, Lo et Wu) was examined in a net pen experiment. A total of 10 dietary treatments were compared. Nine diets were formulated to contain 363 g kg⁻¹ digestible protein and 14.8 MJ kg⁻¹ digestible energy, and a dietary treatment consisting of raw fish (RF) served as reference. In the formulated diets, the control diet contained 350 g kg⁻¹ herring meal, whereas in the other eight diets, the fishmeal were replaced by MBM (30% fishmeal replacement), PM (50% fishmeal replacement), a blend of PM, MBM, FM and BM (30%, 50% and 80% fishmeal replacement), or a blend of PM, MBM and BM (30%, 50% and 80% fishmeal replacement), respectively. Cuneate drum fingerling (initial body weight 28 g) were fed the test diets for 8 weeks. Specific growth rate (SGR), final body weight (FBW), nitrogen retention efficiency (NRE), condition factor and contents of moisture, crude protein and crude lipid in carcass were not significantly different between fish fed the formulated diets. Fish fed the formulated control diet exhibited lower SGR and FBW, but higher FCR, NRE, hepatosomatic index and crude lipid content in carcass and liver than those of the fish fed the RF. Results of the present study indicate that combination of rendered animal protein ingredients can replace most of the fishmeal in practical diets for cuneate drum.     

Substitution of fish meal by Jatropha curcas kernel meal: Effects on growth performance and body composition of white leg shrimp (Litopenaeus vannamei)

Jatropha curcas (L.) is a multipurpose and drought‐resistant tree, widespread throughout the tropics and subtropics. Its seeds are rich in oil and protein (contains 600–660 g kg^?1 crude protein similar to fish meal). It is being promoted as a biofuel plant. Jatropha kernel meal obtained after oil extraction is an excellent source of protein. However, presence of toxic and antinutritional constituents restricts its use in fish and shrimp feed. An 8‐week experiment was conducted to evaluate the nutritional quality of the detoxified Jatropha kernel meal (DJKM) in white leg shrimp (Litopenaeus vannamei). Shrimp (60) with an initial average body weight of 4.46 ± 0.64 g were randomly distributed into three treatments with four replicates and fed isonitrogenous and isoenergetic diets (crude protein 350 g kg^?1, crude lipid 90 g kg^?1): Control (fish meal‐based protein), JC₂₅ and JC₅₀ (25% and 50% of fish meal protein replaced by DJKM). Higher (P < 0.05) body mass gain, specific growth rate and metabolic growth rate were observed in DJKM‐fed groups than in Control group. However, lower (P > 0.05) feed conversion ratio was observed in DJKM‐fed groups, while protein efficiency ratio exhibited an opposite trend. Protein, ash and gross energy content of the whole shrimp body were higher (P < 0.05) in DJKM‐fed groups compared to Control group. Moisture and lipid content of the whole shrimp body did not differ significantly among the three groups. Cholesterol level in plasma was highest (P < 0.05) in the Control group, followed by JC₂₅ and JC₅₀ groups; all being significantly different. In conclusion, DJKM is a promising fish meal replacer in shrimp diets.     

Long-term evaluation of extruded diets compared with raw fish moist diet for growing Korean rockfish, Sebastes schlegeli (Hilgendorf)

A long‐term experiment was conducted in sea cages to compare three experimental extruded pellet (EP) diets with a raw fish moist pellet (MP) diet for Korean rockfish, Sebastes schlegeli (Hilgendorf). White fishmeal (WFM), soybean meal (SM) and fishmeal analogue (BAIFA‐M?)‐based experimental EP diets were formulated to be isonitrogenous and isocaloric with 50% crude protein (CP) with available energy of 16.7 kJ g^?1 diet. An MP diet made of 80% frozen horse mackerel + 20% commercial binder meal was also included in the experiment. The proportions of the major protein ingredients in three experimental EP diets were as follows: WFM diet, 100% WFM; SM diet, 70% WFM + 30% SM; BAIFA‐M? diet, 70% WFM + 30% BAIFA‐M?. The experiment was divided into three periods according to fish size: period I, initial weight of 20.2 ± 3.6 g (mean ± SD); period II, initial weight of 57.6 ± 4.7 g (mean ± SD); period III, initial weight of 96.3 ± 6.9 g (mean ± SD). There were no significant differences in weight gain, feed efficiency ratio, thermal‐unit growth coefficient, specific growth rate, haemoglobin, or haematocrit among fish that were fed the four diets during all three periods. However, fish that were fed the MP diet had a lower survival rate than the fish that were fed the other three EP diets for all periods. These results strongly suggest that EP diets could be developed to replace MP diet for the grow‐out stage of production of Korean rockfish without adverse effects on growth performance.     

Growth,absorption and assimilation efficiency by mature cuttlefish (<Emphasis Type="Italic">Sepia officinalis</Emphasis>) fed with alternative and artificial diets

The effects of feeding three natural frozen diets, grass shrimp (Palaemonetes sp.), crayfish (Procambarus clarkii) and fish (Sardina pilchardus) and two semi-humid artificial diets (based on fish powder) to mature cuttlefish, Sepia officinalis, were analysed. Growth and feeding rates (GR and FR, % BW day⁻¹), food conversions (FC, %), and total protein and lipid composition of the diets were determined. Digestive gland to body weight ratio and absorption efficiency were calculated for each diet. Cuttlefish fed shrimp and crayfish grew larger (1.5 and 1.1% BW day⁻¹, respectively) compared to the other diets. Shrimp promoted the highest FC, followed by crayfish, and sardine. The highest FR was obtained for cuttlefish fed crayfish (8.4% BW day⁻¹). Although both artificial diets were accepted, none produced growth. A positive correlation (r = 0.96) between cuttlefish ingestion rate and digestive gland weight was obtained. Some cannibalism occurred among cuttlefish fed the artificial diets during the last week of the experiment. According to the results obtained, P. clarkii could be used as an alternative prey to shrimp for rearing adult mature (>50 g) S. officinalis.     

Developing a low fishmeal diet for juvenile Pacific white shrimp,Litopenaeus vannamei,using the nutritional value of FM as the reference profile

An 8‐week feeding trial was conducted to evaluate the effect of fish‐meal replacement on growth performance, antioxidative ability, immune capacity and haemolymph metabolites of Litopenaeus vannamei. A 250 g/kg fish‐meal diet was used as control (Diet 1). Other two diets contained 100 g/kg fishmeal, Diet 2 was supplemented with three indispensable amino acids, and Diet 3 was supplemented with microbalance components and phytase. Weight gain was lower in shrimp fed the Diet 2 than shrimp fed the Diet 1. Feed efficiency, protein efficiency ratio and survival were higher in shrimp fed the Diet 1 than other groups. Glutathione and nitric oxide contents in haemolymph were decreased in shrimp fed the Diet 2, and nitric oxide synthetase, phenoloxidase, acid phosphatase and myeloperoxidase activities showed the similar tendency. In hepatopancreas, antioxidative ability and immune capacity also lower in shrimp fed the Diet 2. In haemolymph, 21 differential metabolites were identified, and 13 metabolism pathways were affected by different diets. Generally, the fishmeal inclusion level could be reduced from 250 g/kg to 100 g/kg without affecting the growth performance of L. vannamei, and meanwhile, the protein utilization efficiency and antioxidative ability of shrimp fed the low fishmeal diets should be more focused on in future studies.