Growth, feed efficiency, digestibility and nutrient distribution in Atlantic cod (Gadus morhua) fed two different fish meal qualities at three dietary levels of vegetable protein sources

Atlantic cod were fed six diets where the ratio of protein from fish meal to vegetable protein were varied from 91%, 67% to 46%, respectively. The experimental groups were performed in triplicate in a 20 week growth trial, increasing fish weight from about 167 g to 690 g. The vegetable protein sources constituted full-fat soybean meal and corn gluten meal at a fixed ratio of 1:2, and replaced either a high quality fish meal (DC_Mink 92.3%) or a lower quality fish meal (DC_Mink 85.6%) in the diet. All diets were extruded and balanced to be equal in gross energy, crude protein, lipid, carbohydrate, lysine and phosphorus. No difference in growth (SGR 1%) was observed comparing the two fish meal qualities. However, feed intake was significantly higher (9%) and feed efficiency lower (10%) for lower quality fish meal compared to high quality fish meal. Protein and amino acid digestibility was significantly reduced in the lower quality fish meal, while unaffected by vegetable protein inclusion for both fish meal qualities. Protein utilization as measured by protein efficiency ratio and net protein value was not affected by fish meal inclusion, except in the diet using lower quality fish meal and high vegetable protein inclusion. Lipid and energy digestibility was significantly reduced by vegetable protein inclusion for both fish meals. The lower fish meal quality increased lipid deposition in the liver and affected slaughter quality of cod by increasing HSI and dressing out percentage at low and intermediate substitution levels. Muscle composition showed small dietary changes except for arginine, while liver fatty acid composition clearly reflected fatty acid profile of full-fat soya in the diets. Corn gluten meal and full-fat soybean meal (2:1) can replace approximately 50% of dietary protein without affecting feed intake, growth, protein digestibility or slaughter quality of cod when exchanging high quality fish meal. For the lower quality fish meal diets some lower inclusion of vegetable protein sources seem to be acceptable.     

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.     

Apparent digestibility coefficients of selected protein feed ingredients for loach Misgurnus anguillicaudatus

Apparent digestibility coefficients of dry matter, crude protein, lipid and energy, and amino acids availability in white fish meal, brown fish meal, meat meal, fermented soybean meal, soybean meal and rapeseed meal were determined for loach (Misgurnus anguillicaudatus) (12.05 ± 0.21 g), using a reference diet with 5 g kg^?1 chromic oxide and test diets that contained 700 g kg^?1 reference diet, by weight, and 300 g kg^?1 of the test feed ingredients. The juvenile loach was held in 300‐l tanks at a density of 30 fish per tank. White fish meal, brown fish meal, meat meal and fermented soybean meal had highest apparent digestibility coefficients (ADCs) of dry matter, crude protein and gross energy among ingredients tested, ranged from 50.4% to 60.9% for dry matter, from 64.6% to 88.4% for crude protein and from 57.9% to 79.0% for gross energy. The apparent digestibility coefficients of dry matter ranged from 61.0% to 66.9% for animal products and 50.4% to 60.7% for plant products. For crude protein, apparent digestibility coefficients of protein exceeding 80% were observed for white fish meal, brown fish meal, meat meal and fermented soybean meal, and the apparent digestibility coefficients of protein in rapeseed meal were the lowest among all the treatments. Lipids from both animal and plant feedstuffs were poorly digested by loach, ranging from 64.0% to 77.6%. The apparent digestibility coefficients of energy were similar to those of dry matter and protein, and the highest and lowest ADCs of energy were found in WFM and RM, respectively. The loach used dietary phosphorus from the animal feedstuffs more efficiently than from plant feedstuffs (soybean meal and rapeseed meal), with ADC‐values ranging from 42.3% to 53.1% and from 25.1% to 32.7%, respectively. For the animal products, the availabilities of amino acids in white fish meal and brown fish meal were higher than that in meat meal, expect for Met, Asp, Pro, Gly, and Cys. Among all the plant products, the availabilities of amino acids in fermented soybean meal were higher than in soybean meal and rapeseed meal, and thus had a greater potential to be used as a dietary replacement of fish meal in loach diets.     

Digestive function and intestinal integrity in Atlantic salmon (Salmo salar) fed kernel meals and protein concentrates made from yellow or narrow-leafed lupins

This study assessed the effects of yellow lupin (Lupinus luteus) and narrow-leafed lupin (L. angustifolius) kernel meals and protein concentrates on the gastrointestinal integrity, capacity for digestive hydrolysis, and digestibility of nutrients in Atlantic salmon. A basal diet (FM) was made from fish meal, wheat, and fish oil. Six additional diets were formulated by replacing 30% of the FM diet with lupin kernel meal made from L. l. cv. Wodjil (LKM), L. a. cv. Belara (BKM), and L. a. cv. Myallie (MKM), lupin protein concentrates made from the same L. l. (LPC) and L. a. cv. M (MPC), or extracted soybean meal (SBM). All diets were extruded. Each diet was fed to three groups of 176 g salmon kept in 1 m² tanks with 5.6 °C saltwater for 3 weeks prior to sampling of blood, intestinal organs, digesta, and faeces. Inclusion of lupin meals in the diets resulted in harder and more condensed feed particles. Ulcer-like lesions were observed in the stomach of fish from all feeding groups, and this was worsened by lupin in the diet, but did not appear to be pellet hardness related. No consistent altered morphology was observed in the distal intestine (DI) of fish fed the FM and lupin diets, while the DI of fish fed SBM showed consistent and typical soybean meal-induced pathomorphological changes. Plasma cholesterol was higher when feeding MKM and LKM than when feeding FM, MPC, and LPC, with intermediate levels when feeding BKM and SBM. Feeding LKM and LPC resulted in a higher weight of the GIT when related to body weight. Trypsin activity and bile acid concentration were generally higher in digesta from the pyloric (PI) and mid (MI) intestine when feeding FM and lupin diets than when feeding SBM, while the opposite was seen for trypsin activity in digesta from DI. There were no effects of diet on leucine aminopeptidase (LAP) and maltase activity in PI and MI, but in DI the activity of these brush border enzymes were significantly lowered when feeding SBM. SBM in the diet resulted in watery faeces and lowered apparent digestibility of lipid, but this was not observed when feeding the lupin diets. To conclude, the tested lupin kernel meals and protein concentrates did not alter the intestinal function in Atlantic salmon when included at 30% of the diet. Dietary lupin was, however, involved in the worsening of ulcer-like gastric lesions.     

Digestive capacity, intestinal morphology, and microflora of 1-year and 2-year old Atlantic cod (Gadus morhua) fed standard or bioprocessed soybean meal

The objectives of this work were to evaluate how dietary soybean meal (SBM) or a soy meal made by bioprocessing the SBM (BPSBM) to remove anti-nutritional factors affected hydrolytic capacity, amino acid absorption, intestinal morphology, and microflora along the intestinal tract of Atlantic cod at two life stages. Three fish meal based standard cod diets were formulated to contain no soy (FM control), 25% SBM, or 22% BPSBM. Prior to sampling the diets were fed to duplicate groups of 0.5 kg (1-year old) and 1.7 kg (2-year old) cod for a period of 3 months, and the groups reached 0.9 and 2.5 kg, respectively. Digesta was then sampled from different intestinal sections for analyses of trypsin and amylase activity as well as absorption of amino acids, nitrogen, and sulphur. Gastrointestinal sections were sampled for measurements of relative weight (kg^− 1 body weight), and tissues from these sections were sampled for analyses of brush border enzyme (alkaline phosphatase (ALP), leucine aminopeptidase (LAP), and maltase) activity and histological examination. Microflora was sampled from both digesta and the intestinal wall. The SBM diet stimulated relative growth of all gastrointestinal sections except the distal intestine in both age classes. Relative growth of the pyloric intestine was also stimulated by BPSBM. The pyloric caeca and the upper mid intestine were found to be the major sites for enzymatic hydrolysis of protein and starch and for amino acid absorption. Dietary SBM and BPSBM did not alter the activity of trypsin and LAP, but the activity of these enzymes in the proximal intestine was affected by age, being higher in 1-year old than in 2-year old cod. The rate of amino acid, nitrogen, and sulphur absorption along the gastrointestinal tract was not affected by SBM, but was slowed by BPSBM. Dietary SBM or BPSBM did not alter the morphology of the intestinal mucosa in any sections of the cod intestine. The distal-most structure of the intestine, a compartment with inlet and outlet (anus) valves, showed very high microbial colonisation in the mucosal brush border. Inclusion of SBM in the diet changed the intestinal microflora, increasing the population level of transient bacteria in the pyloric and mid intestine, but reducing the population level of adherent bacteria throughout the intestine. To conclude, Atlantic cod appeared to have a robust and flexible digestive system able to adjust to high dietary levels of soy protein meals.     

Evaluation of a fish meal analogue as a replacement for fish meal in practical diets for Pacific white shrimp Litopenaeus vannamei

Three six‐week growth trials and a digestibility trial were conducted to evaluate a fish meal analogue (FMA) as a replacement for fish meal (FM) in shrimp feeds. Trials 1 and 2 evaluated and confirmed the potential of FMA supplementation (0, 48.5, 97, 145.5 and 194 g/kg) as a replacement for FM up to 200 g/kg without balancing for phosphorus (P) in practical diets for juvenile Pacific white shrimp L. vannamei. At the end of trial 1, shrimp offered diets containing 48.5 g/kg FMA exhibited significantly higher weight gain (WG) than those fed with the diet containing 145.5 g/kg FMA. At the end of trial 2, dietary FMA inclusion at 48.5 and 97 g/kg significantly improved WG and protein retention (PR), while reducing FCR and protein content of shrimp body compared to the diet containing 194 g/kg FMA. To determine whether P deficiency is the cause of reduced growth, the third trial was conducted utilizing equivalent diet but balanced for P. At the end of trial 3, shrimp fed diet containing 48.5 g/kg FMA+P showed significantly higher WG and PR than those fed diet containing 145.5 g/kg FMA+P. No decreasing trend of growth was detected in the diets containing FMA compared to the FM‐based diet. Apparent digestibility coefficients of dry matter, energy, protein and amino acids of FMA were determined using chromic oxide as an inert maker and the 70:30 replacement technique. The energy, protein and individual amino acid digestibility of FMA were significantly lower than those of soybean meal and FM which were run at the same time. Results of this work indicate that FMA can replace up to 200 g/kg FM in shrimp diets with supplemental inorganic P. Given the good growth across the range of inclusion without any indication of a growth depression, the low nutrient digestibility of FMA may be due to an atypical response or the product simply does not work with the testing technique.     

Supplemental effect of bile salts to soybean meal-based diet on growth and feed utilization of rainbow trout <Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>

A feeding experiment was conducted to evaluate the supplemental effect of bile salts to a defatted soybean meal-based non-fish meal diet for rainbow trout Oncorhynchus mykiss. A fish meal-based diet (FM) and two non-fish meal diets with and without bovine bile salts (SC+B and SC, respectively) were fed to fish (13 g initial weight) for 10 weeks. Fish fed diet SC showed inferior growth and feed efficiency, while bile salt supplementation improved the parameters to the same levels as fish fed diet FM. Crude fat and starch digestibility of diet SC-fed fish decreased after the 10-week feeding trial compared to the data obtained with fish that had no experience of the diet. Total biliary bile salt content and intestinal maltase activity of fish fed diet SC were the lowest among treatments, while these parameters were improved by bile salt supplementation. Morphological changes occurred in the distal intestine and liver of the diet SC group, although the histological features of fish fed diet SC+B were similar to those of fish fed diet FM. These results suggest that bile salt supplementation to a soybean meal-based diet improves the nutrient utilization by normalizing digestive processes in rainbow trout.     

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.     

Exogenous xylanase improves growth,protein digestibility and digestive enzymes activities in Nile tilapia,Oreochromis niloticus,fed different ratios of fish meal to sunflower meal

A 3 × 2 factorial experiment was designed to evaluate the effect of different ratios of fish meal (FM): sunflower meal (SFM) with or without exogenous xylanase supplementation on growth, feed utilization, digestive enzymes activities, apparent digestibility, intestinal and liver morphology and chemical composition of Nile tilapia, Oreochromis niloticus. Three isonitrogenous (329.80 g/kg of crude protein) and isoenergetic (18.46 MJ/kg gross energy) experimental diets were formulated as SFM₁ (FM:SFM = 2:1), SFM₂ (FM:SFM = 1:1) and SFM₃ (FM:SFM = 1:2) based on protein content. Each diet was supplemented with 0 or 0.5 g/kg of exogenous xylanase and was fed to triplicate groups of twelve fish (with initial weight, 1.31 ± 0.02 g) for 84 days. After 84 days of feeding period, the highest weight gain, specific growth rate, protein efficiency, protein productive value and the best feed conversion ratio were recorded in fish fed either SFM₁ or SFM₂ supplemented with exogenous xylanase. Whereas lowest growth performance was recorded in fish fed SFM₂ and SFM₃ un‐supplemented with xylanase. The highest activities of chymotrypsin, trypsin, lipase, amylase, alkaline phosphatase and cholecystokinin were observed in fish fed SFM₁ and SFM₂ diets supplemented with xylanase. The highest ADCs of dry matter, protein, lipid and digestible energy were recorded in fish fed SFM₁ and SFM₂ diets supplemented with exogenous xylanase. Supplementation of exogenous xylanase improved muscularis mucosa thickness, height of mucosal folds and enterocytes of intestinal fish. Addition of exogenous xylanase increased the calcium and phosphorus retention. Results of this study indicated that the addition of exogenous xylanase to diet containing high inclusion level of sunflower meal improved growth, digestive enzymes, nutrient digestibility, histological morphometric of liver and intestine and nutrient retention.     

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

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

摄食促进物质对许氏平鲉摄食和生长的影响 不同地理群体星突江鲽养殖子一代群体遗传多样性分析

以初始体重为49．83±．17g的许氏平鲇Sebastesschlegeli为实验对象,进行为期30d的摄食生长实验。共配制6种等氮等能饲料,其中5种饲料以鱼粉和豆粕为蛋白源（豆粕蛋白替代30％的鱼粉蛋白）配制出基础饲料,分别在基础饲料中不添加摄食促进物质和添加0．3％的商品诱食剂、二甲基-β-丙酸噻亭（DMPT）、甜菜碱和柠檬酸配制成5种豆粕替代饲料,其余1种为鱼粉不替代饲料作为对照组,研究摄食促进物质对许氏平鲇摄食和生长的影响。结果表明,当豆粕取代饲料中添加甜菜碱和柠檬酸时,许氏平铀的特定生长率、饲料效率、蛋白质效率以及肝脏、肠胰蛋白酶活力都显著高于不添加摄食促进物质组（P〈0．05）;当不添加摄食促进物质时,摄食率显著低于鱼粉不替代组（P〈O．05）;而添加DMPT、甜菜碱和柠檬酸时,摄食率与鱼粉不替代组比较没有显著差异（P〉0．05）;肝体指数都明显地低于鱼粉不替代组。结果表明,豆粕替代30％的鱼粉蛋白时,添加0．3％的甜菜碱或柠檬酸能够显著提高许氏平鲇幼鱼对饲料的摄食率和生长率。     

Effects of extrusion and inclusion level of soybean meal on diet digestibility, performance and nutrient utilization of gilthead sea bream (Sparus aurata)

The objective of this study was to evaluate the effects of soybean meal inclusion and treatment on the performance of two sizes of gilthead sea bream (small, 9 g and large 50 g mean initial weight). Seven diets were fed containing soybean meal, before (SBM) and after (SBMex) its extrusion, at increasing levels (0% as control and about 20, 30, and 40% for both soy forms used). For large fish effects on digestibility, as well as on trypsin activity levels and moisture at upper (UI), mid (MI) and lower (LI) intestine were also evaluated, following the growth trial. All experiments were conducted at 22 ± 2 °C. Specific growth rate and whole body composition were not affected by soy inclusion, however an adverse effect of inclusion level on feed conversion ratio and protein productive value was apparent for both soy products and fish sizes. Extrusion of soy affected differently large and small fish improving both protein productive value and feed conversion ratio of large fish, but only protein productive value of small fish. Plasma cholesterol decreased with inclusion level of both types of soy, the effect being significant only at the higher level. Liver lipid and glycogen deposition in large fish appeared to be mostly affected by digestible starch intake, increasing with increased intakes, the same being apparent for hepatosomatic index. Soy inclusion did not appear to have any effect on nutrient digestibilities. Trypsin activity (TA) was decreased from UI to LI for all diets and was significantly higher in C diet compared to all other diets at all segments. Extrusion of SBM increased significantly TA levels. Hydration of digesta in LI increased for low soy levels and decreased for high soy levels compared to the control diet.     

Replacement of fish meal by meat and bone meal in diets for large yellow croaker, Pseudosciaena crocea

A growth experiment was conducted to investigate the effects of replacement of fish meal (FM) by meat and bone meal (MBM) in diets on the growth and body composition of large yellow croaker (Pseudosciaena crocea). Six isonitrogenous (43% crude protein) and isoenergetic (20 kJ g^− 1) diets replacing 0, 15, 30, 45, 60 and 75% FM protein by MBM protein were formulated. Each diet was randomly allocated to triplicate groups of fish in sea floating cages (1.0 × 1.0 × 1.5 m), and each cage was stocked with 180 fish (initial average weight of 1.88 ± 0.02 g). Fish were fed twice daily (05:00 and 17:30) to apparent satiation for 8 weeks. The water temperature ranged from 26.5 to 32.5 °C, salinity from 32 to 36‰, and dissolved oxygen content was approximately 7 mg l^− 1 during the experimental period. Survival decreased with increasing dietary MBM and the survival in the fish fed the diet with 75% protein from MBM was significantly lower than other groups (P < 0.05). There were no significant differences in specific growth rate (SGR) among the fish fed the diets with 0 (the control group), 15, 30 and 45% protein from MBM. However, SGR in the fish fed the diets with 60 and 75% protein from MBM were significantly lower than other groups (P < 0.05). No significant differences in feeding rate were observed among dietary treatments. The digestibility experiment showed that the apparent digestibility coefficients (ADC) of dry matter, protein, lipid and energy of MBM were significantly lower compared with those of FM (P < 0.05). Essential amino acid index was found to be correlated positively with SGR in the present study, suggesting that essential amino acid balance was important. Body composition analysis showed that the carcass protein and essential amino acids were not significantly affected by dietary MBM. The lipid and n-3 highly unsaturated fatty acid (n-3 HUFA) in fish muscle, however, significantly decreased with increasing dietary MBM. These results showed that 45% of FM protein could be replaced by MBM protein in diets of large yellow croaker without significantly reducing growth. It was suggested that the reduced growth with higher MBM was due to lower digestibility and imbalance of essential amino acids.     

Apparent digestibility of selected feed ingredients for white shrimp Litopenaeus vannamei,Boone

Apparent digestibility coefficients of dry matter (DM), crude protein, crude lipid, gross energy, phosphorus and amino acids in Peruvian fish meal (FM), fermented soybean meal, extruded soybean meal, soybean meal, peanut meal, wheat gluten meal, corn gluten meal, shrimp byproduct meal, meat and bone meal (MBM), poultry meat meal and plasma protein meal (PPM) were determined for white shrimp (Litopenaeus vannamei). A reference diet (RF) and test diets (consisting of 70% RF diet and 30% of the feedstuff) were used with 0.5% chromic oxide as an external indicator. A total of 1440 shrimp (initial mean body weight 1.05 ± 0.01 g) were randomly stocked into thirty‐six 500‐L fibreglass tanks with 40 shrimp per tank and three tanks per diet. Faeces were collected from triplicate groups of shrimp by a faecal collection vessel attached to the shrimp‐rearing tank. The shrimp were fed to apparent satiation four times a day and the feeding experiment lasted for 6 weeks. Statistics indicate that apparent DM digestibilities for white shrimp (L. vannamei) were the highest for FM, ranged 52.83–71.23% for other animal products and 69.98–77.10% for plant products. The protein and lipid from plant and animal sources were well digested by white shrimp. Apparent protein and lipid digestibility were in the range 87.89–93.18% and 91.57–95.28%, respectively, in plant products, and 75.00–92.34% and 83.72–92.79%, respectively, for animal products. The white shrimp demonstrated a high capacity to utilize phosphorus in the ingredients. The apparent phosphorus digestibility ranges of animal feedstuffs and plant feedstuffs were 58.90–71.61% and 75.77–82.30% respectively. Amino acid availability reflected protein digestibility, except that in MBM, for which the availability of some amino acid was lower, possibly due to protein damage during processing. Digestibility information could promote the use of ingredient substitution in least‐cost formulated diets for white shrimp.     

Supplemental iron and phosphorus increase dietary inclusion of cottonseed and soybean meal in olive flounder (Paralichthys olivaceus)

A long‐term feeding experiment was conducted to investigate the use of cottonseed and soybean meal (CS) with iron and phosphorus supplements in diets for olive flounder (Paralichthys olivaceus). Olive flounder with an initial average size of 28.5 ± 0.35 g (mean ± SD) were divided into 15 groups (three tanks per dietary treatment) and fed 480 g kg^?1 crude protein diets in which each of five isonitrogenous diets was formulated to contain different levels of cottonseed/soybean meal (1 : 1) to replace fish meal (FM) with iron and phosphorus supplementations. The five experimental diets were as follows: diet 1 (control), 0%CS; diet 2, 20%CS; diet 3, 30%CS; diet 4, 30%CS + Fe&P; and diet 5, 40%CS + Fe&P. After 26 weeks of feeding trial, no significant differences were observed in weight gain, feed utilization and survival among all the treatments. The total gossypol accumulation in liver of fish fed diets supplemented with iron was significantly lower than that of fish fed diets without supplementation of iron. The results indicate that the addition of iron in diets could prevent the absorption of free gossypol. The findings in this study suggest that dietary supplements of iron and phosphorus could increase the inclusion of cottonseed and soybean meal for FM replacement in diets for marine fish species.     

Using a fermented mixture of soybean meal and earthworm meal to replace fish meal in the diet of white shrimp,Penaeus vannamei (Boone)

An experiment was conducted to evaluate the potential of a Bacillus subtilis E20‐fermented mixture (FSFEM) containing soybean meal (SBM) and Eisenia fetida earthworm meal (EM) at a ratio of 4:1 to increase the methionine level in order to satisfy the methionine requirement of white shrimp, Penaeus vannamei in a diet with fish meal (FM) completely replaced by mixtures. B. subtilis E20 fermentation improved the mixture's palatability and utilization based on better growth performance in comparison to shrimp fed FSEM (contains fermented SBM and EM at a ratio of 4:1) diets. FSFEM is a good substitute for FM. Maximal replacement levels of FM with FSFEM were 80% in a shrimp diet with 37% of crude protein and 7% of crude lipid based on weight gain and 100% based on feeding efficiency. In addition, shrimp fed experimental diets had no significant differences in survival after being challenged by Vibrio alginolyticus. It is suggested that B. subtilis E20‐FSFEM has the potential to replace FM in cultured shrimp diets.     

Effects of the partial substitution of dietary fish meal by differently processed soybean meals on growth performance, nutrient digestibility and activity of intestinal brush border enzymes in the European sea bass (Dicentrarchus labrax)

This study evaluated the effects of replacing fish meal (FM) in the diet of European sea bass (Dicentrarchus labrax) with differently processed soybean meals on growth performance; apparent digestibility coefficients (ADCs); the activity of alkaline phosphatase and the brush border digestive enzymes: leucine amino peptidase, maltase and γ-glutamyl transpeptidase; and the fish morphometric and flesh quality. European sea bass with an initial average body weight of 187.8 ± 1.4 g, were fed either a FM based (control) diet or a soy replacement isoproteic, isolipidic and isocaloric diet. The treatments consisted replacing FM protein by: 25% toasted, dehulled and solvent-extracted soybean meal (SE25); 50% dehulled and toasted soy seeds subjected to dry extrusion and mechanical oil extraction (ME50); 50% enzyme-treated soybean meal (ET50) and an inclusion of 60% composed of 30% toasted, dehulled and solvent-extracted soybean meal and 30% enzyme-treated soybean meal (SE + ET/60). ADCs values of dry matter, crude protein, crude lipid and gross energy did not significantly differ between ME50 and SE + ET/60 but both of them were inferior to the other treatments (P < 0.05). Compared with the control FM-based diet, only the group that consumed the ME50 diet had lower specific growth rate, feed conversion ratio and gross protein retention efficiency values (P < 0.05). The protein efficiency ratio did not differ between the FM-based control group and all other soy derivate groups (P > 0.05). In order to gain more insight on the effects of the diet on fish growth, activity of the brush border enzymes was measured. No significant differences were found in leucine amino peptidase and maltase activities, between the control group and the other soy derivate groups. The activity of γ-glutamyl transpeptidase was significantly higher in the upper section in fish that consumed the control diet compared with fish that consumed the soy derivate diets. Yet, the main activity of this enzyme was found in the lower intestinal section. In all the soy derivate diets except for the SE25 diet, the activity of alkaline phosphatase was significantly lower than its activity in the control diet. Feeding diets that include various types and levels of soybean derivatives did not affect the whole body composition and slaughter yield but significantly reduced liver weight. The results show that in methionine supplemented diets, FM can be replaced in terms of protein by 25% SE, 50% ET or 60% soy composed of 30% SE and 30% ET without hampering fish performance. The inclusion of 50% protein from ME resulted in significantly lower growth performance and feed utilization.     

豆粕替代鱼粉对牛蛙生长性能、消化酶活性和肠道健康的影响

为探讨豆粕替代鱼粉对牛蛙(Rana catesbeiana)生长性能、表观消化率、消化酶活性和肠道健康的影响,以基础饲料为对照,豆粕替代基础饲料中50%和100%的鱼粉形成3种等氮等能的试验饲料,分别记为FM、B1和B2组,饲喂初始体重为(40±0.3)g的牛蛙,进行为期30 d的摄食生长试验,测定增重率、特定生长率、饲料效率、营养物质消化率、蛋白酶、淀粉酶、脂肪酶等指标。结果显示:各组间牛蛙成活率无显著差异;豆粕替代鱼粉显著降低牛蛙的增重率、饲料效率和蛋白质效率,显著降低其对饲料干物质、蛋白质和总能的表观消化率。肠道消化酶分析结果显示,豆粕100%替代鱼粉显著降低了牛蛙空肠和回肠蛋白酶活性,B1和B2组牛蛙回肠脂肪酶活性显著低于FM组,淀粉酶活性显著高于FM组。对牛蛙肠道组织形态观察发现,豆粕替代鱼粉后肠道绒毛高度、肌层厚度和柱状上皮高度显著降低。豆粕替代鱼粉后肠道促炎因子IL-1β、IL-17、IL-8和TNF-αmRNA的表达量显著升高。结果表明,牛蛙饲料中大量使用豆粕会对其生长和饲料利用产生负面的影响,并诱导肠道炎症发生。     

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.     

Effects of fish oil and partial fish meal substitution with oilseed oils and meals on growth performance, nutrient utilization and health of the rainbow trout Oncorhynchus mykiss

A feeding trial was conducted to investigate the effects of the replacement of dietary fish meal and fish oil with oilseed meals (soybean or canola) and canola oil on growth, nutrient utilization, body composition, diet digestibility and hematological parameters of rainbow trout Oncorhynchus mykiss. Seven diets were used; the control diet (designated FM) contained fish meal and fish oil as the main protein and lipid sources. For the experimental diets, 40% of fish meal protein was substituted with soybean meal, canola meal or a soybean/canola meal mixture, and these diets (designated SM, CM and SCM, respectively) contained fish oil as the lipid source. Three additional diets (SM?+?CO, CM?+?CO and SCM?+?CO) were formulated with the same vegetable protein meals but with fish oil replaced by canola oil. Fish were fed twice daily to apparent satiation for 11?weeks. The growth of fish fed the CM?+?CO diet was significantly lower than that of fish fed the FM, SCM, SM?+?CO and SCM?+?CO diets. The feed conversion ratio (FCR) was significantly better in fish fed the FM and SCM?+?CO diets than in fish fed the CM and CM?+?CO diets. Furthermore, feed intake was significantly lower for fish fed the CM?+?CO diet than in fish fed the SCM diet, and lipid digestibility of the CM?+?CO diet was significantly lower than that of all other diets. No significant differences of body composition were observed. Circulating leukocyte levels, leukocyte ratios and serum lysozyme activity remained unaffected by dietary treatment. However, it was observed that fish fed the CM?+?CO diet displayed hematocrit levels significantly lower (P?<?0.05) than that of fish fed the other diets. The results indicate that when diets contain either fish oil or canola oil, canola meal and soybean meal can be incorporated into rainbow trout feeds at a combined 32% inclusion level (replacing 40% of fish meal protein) without inducing significant negative effects on growth, nutrient utilization or health.