The influence of feeding Atlantic salmon for 90 days on diets that excluded fishmeal (FM) and fish oil (FO) was examined for influence on various quality traits. In addition, the effect of adding krill meal (KM; 0%, 2.5%, and 5%), as a putative feed palatant was also examined. Total replacement of FM/FO had a limited effect on production characteristics, affecting percentage yields of headed and gutted control fish and their standard length (p < 0.05). Variances between dietary groups were observed for pigmentation, and plant protein-based KM-free-fed fish returned deeper hues across their belly, NQC (Norwegian Quality Cut), and back portions (p < 0.03). No differences were measured for relative fin condition. δ13C and δ15N concentrations were lower and higher, respectively (p < 0.05) for fish fed the FM/FO-based diet. δ13C:δ15N likewise differed between treatments with FM/FO-fed salmon expressing higher ratios. Fillet mechanical characteristics varied with fish fed on animal protein-based diets, without KM expressing higher springiness and resilience (p < 0.05). Fish fed plant-based diets were generally preferred by younger taste testers. The results from this trial illustrate that FM/FO can be completely removed from salmon diets without problematic effects on quality and palatability attributes.

Objective This study aimed at evaluating the role of a novel commercial product, MrFeed Pro50 FF (MP50), as a functional ingredient with which to formulate low-fish-meal diets for Largemouth Bass Micropterus nigricans. Methods Seven test diets were examined. A reference diet (RD) contained 400-g/kg fish meal, and a control diet (C) was formulated by replacing 60% of the fish meal in RD with poultry by-product meal. The other five diets were formulated by adding MP50 to C at 5.0 (D50), 7.5 (D75), 10.0 (D100), 12.5 (D125), or 15.0 (D150) g/kg. Fish (initial body weight = 9.2 +/- 0.1 g) were fed the test diets for 8 weeks. Result The MP50 supplementation level significantly affected weight gain, final body weight, carbon retention efficiency, energy retention efficiency (ERE), hepatosomatic index (HSI), viscerosomatic index (VSI), the ratio of fish meal consumption to fish production (RCP), and carbon waste. The weight gain of fish fed D50, D75, and D100 was greater than that of fish fed C and D150. The ERE was greater in fish fed D50 and D100 than in fish fed C and D75. The HSI and VSI were greater and nitrogen and carbon wastes were lower for fish fed D50 and D100 than in fish fed C. Fish fed D50, D75, and D100 exhibited greater weight gain and lower RCP values compared with fish fed RD. The weight gain of fish fed RD did not significantly differ from the weight gain of fish fed C, D125, and D150, confirming that the minimum fish meal level could be reduced to 160 g/kg. Conclusion This study indicates that MP50 at 5.0-10.0 g/kg can be used as a functional ingredient in low-fish-meal diets for Largemouth Bass.

The purpose of this study was to determine the influence of krill meal (KM) inclusion at various levels (0%, 2.5%, 5%) in plant-based and animal-based feeds, that were fishmeal (FM) and fish oil (FO) free, on Atlantic salmon growth. A FM/FO feed containing 0% KM was the control. Using a 2 × 3 factorial approach, diets were randomly assigned to one of 28 0.5 m3 flow-through tanks (n = 4 tanks per diet) initially stocked with 60 fish (148.4 ± 12.9 g; 23.6 ± 0.8 cm; condition factor (K) = 1.16 ± 0.08) each. Salmon were fed for 90 days using automatic feeders ad libitum. On day 45, stocking densities were reduced to 45 fish per tank by the random removal of 15 individuals to remove any potential of density affecting growth through the trial end. Water temperature, oxygen saturation, pH, and salinity throughout the trial were 11.8 °C, 103.5%, 7.38, and 32.0 g L−1, respectively. Fish fed plant-based feed without KM were lighter (p < 0.05) than all other groups at day 45 and 90, but those fed a plant-based feed with KM had comparable growth and feed intake compared to that of fish fed the control diet. Irrespective of the presence of KM, animal-based feeds achieved comparable weight growth (p > 0.05) to the control and 5% KM plant-based groups, with KM increasing feed intake (p < 0.05). Between day 45 and 90, feed conversion ratios increased in all groups except the control and 0% KM plant-based group, while specific growth rates (SGRs) decreased for all except the 0% KM plant-based diet. Between-group differences (p < 0.05) were also noted for the thermal growth coefficient. No differences were recorded in visceral or intestinal weight, and whole-body lipid levels were identical, proportional for all groups. Although differences (p < 0.05) were apparent in the concentrations of individual fillet fatty acids between groups, a 75 g serving size of any treatment would be sufficient to exceed daily intake recommendations for EPA + DHA. This trial determined that benefit, in terms of feed intake and growth performance, was gained when KM was added to plant-based feeds. However, no such advantage was observed when KM was used with animal-based feeds.

Largemouth bass (LMB; similar to 15.2 g initial weight) was fed one of the five experimental, and a fishmeal (FM)/fish oil (FO) control diet and two commercial (Xinxin, Coppens) LMB feeds for 10 weeks. Fish were dispersed into 24, 110-L aquaria (n = 20/tank) configured as a recirculating system. Aquaria were arbitrarily allocated to dietary treatments in triplicate (n = 60/fish diet). The FM component of experimental diets was replaced using poultry by-product meal and soy protein concentrate. One experimental diet contained FO, whereas in others, FO was replaced with canola, flax and/or algal oil or combinations thereof. At trial end, there were no differences among fish-fed various diets in terms of feed conversion or protein efficiency ratios. Weight gain and survival were similar for experimental groups, and LMB fed the Xinxin commercial feed, but the Coppens feed returned inferior (p < 0.05) weights and higher mortality. Condition factor, fillet yield and intraperitoneal fat ratios were unaffected by diet but hepatosomatic index varied. The Coppens feed caused greatest differences in whole-body protein, lipid and ash contents (p < 0.001). Whole-body fatty acid profiles reflected those of the diet, with algal oil enriched feed illustrating enhanced DHA:EPA ratios.

The complete quantitative essential amino acid (EAA) requirements of aquacultured animals are largely unknown except for a handful of species. This is problematic because formulation of least-cost diets for target animals demands precise knowledge of EAA requirements. One way of approximating EAA requirements is to use correlations between whole-body and/or muscle EAA profiles using essential to total EAA ratios (A/E ratios). This method requires a reference, quantified EAA requirement, usually lysine (Lys). To systematically evaluate the A/E ratio method, muscle AA profiles were measured in 10 species of teleost and whiteleg shrimp. In fish, Lys represented the dominant muscle EAA measured, ranging between 7.06 and 9.58 g/100 g protein, whereas, in shrimp, arginine (Arg) was quantified as the principal EAA. For non-EAA, glutamate (Glu) and glutamine were consistently the NEAA recorded at highest levels whereas, in shrimp, Glu + Gln was highest followed by aspartate (Asp) plus asparagine (Asn). Except for Arg, which was twice that of fish (P < 0.05), whiteleg shrimp expressed similar muscle A/E profiles. Strength of relationship between muscle EAA levels and known requirements were all strongly and positively correlated for non-salmonid species. When using Lys as the reference EAA there were few semblances between measured and estimated EAA requirements.

Barley protein concentrate (BPC) was tested as a protein source in the diets of Atlantic salmon post-smolts. Fish were fed one of four experimental diets consisting of a fish meal/soya protein concentrate control (CT) along with two feeds supplemented with increasing levels of BPC replacing the more costly SPC. A fourth diet partially replaced FM in the high BPC diet with a liquid fish protein concentrate (FPC) made from fish trimmings. No significant differences were observed in terms of growth at the end of the 12-week feeding period, although the protein efficiency ratio (g gain g−1 protein consumed) was significantly lower for the control compared to fish fed diets containing either BPC only or FPC and BPC. This suggests that diets containing BPC had a beneficial effect when compared to the control diet. Furthermore, the lack of any detriment to fish growth in diets containing BPC suggests there are no significant issues regarding any negative effects of potential antinutritional factors which can otherwise be the case with other plant origin products. The data presented in this study indicate that BPC and FPC are products which could be of benefit to salmon culture, and related species, in providing a valuable new raw material to the industry.

Fishery processing by-products are a large resource from which to produce fishmeal and other products for a variety of uses. In this study, testes meal (TM) produced from pink salmon processing by-product was evaluated as a functional ingredient in aquafeeds. Nile tilapia and rainbow trout fry were fed five isonitrogenous and isoenergetic experimental diets for 4 and 9weeks respectively. Two diets were fishmeal-based (FM) and three were plant protein-based (PP). Salmon TM was added to the FM and PP diets at 7% to replace 20% of fishmeal protein (FMTM and PPTM respectively). An additional control diet was prepared in which fishmeal was added to the PP diet to supply an equivalent amount of protein as supplied by TM (PPFM). Inclusion of TM in both the FM- and PP-based diets resulted in higher final body weights, although differences were only significant between rainbow trout fed FM or FMTM diets. Similar differences were calculated for other indices of fish performance, e.g. specific growth rate, feed conversion ratio, protein efficiency ratio and protein retention efficiency. Feed intake was significantly higher for fish fed FMTM compared with FM in rainbow trout. For tilapia, final weights were numerically higher, but not significantly different for fish fed diets containing TM compared with non-TM diets (FM vs. FMTM; PP vs. PPTM). Performance of trout or tilapia fed the PPFM diet did not increase compared with the PP diet. The results indicate that TM addition to both FM and PP diets increased feed intake and also increased metabolic efficiency, demonstrating that TM can be a functional ingredient in aquafeeds.

Eight strains of rainbow trout were introgressed to develop a single strain (H-ARS) that was selected for faster growth when fed a fishmeal-free, plant-based diet (Selection Diet). For four generations, families from these crosses were fed the Selection Diet and selected for increased weight gain. Growth and nutrient retention were compared among H-ARS and two parental strains, the House Creek (HSC) and Fish Lake (FL) fed either a fish meal or Selection diet for 12weeks. There was a significant effect of strain (P<0.01), but not diet on weight gain, and a significant interaction of strain by diet (P<0.05). The H-ARS trout gained more weight averaged across diet (991% of initial wt.) than the HC (924%) or FL trout (483%). The FL trout fed the fish meal diet gained more weight than FL trout fed the selection diet (510% vs 456%). Conversely, H-ARS trout fed the plant-based diet gained more weight than those fed the fish meal diet (1009% vs 974%). HSC trout had similar weight gain fed either diet (922% vs 926%). A significant effect of strain on protein retention (P<0.01) was observed, along with a significant strain by diet interaction (P<0.02). The results demonstrate that rainbow trout can be selectively improved to grow on a plant-based diet.

To determine the potential for improving the conversion and deposition of the omega-3 fatty acids docosahexaenoic acid (DHA; 22:6n-3) and eicosapentaenoic acid (EPA; 20:5n-3) in fish, 44 families of rainbow trout were fed a diet low in these components and then evaluated for their ability to convert and store plant oils that did not contain DHA and EPA in their muscle tissue. The range for EPA and DHA detected in the tissues of different families varied between 1.2 and 2.9%, and 3.8 and 7.1% total fatty acid, respectively. After adjusting for covariates, an averaged heritability of 0.78 +/- 0.11 for DHA and 0.61 +/- 0.17 for EPA was calculated. Expression analysis of genes related to the elongation and conversion of lipids were also analyzed, and significant differences were found in the expression of some genes between groups of families that were delineated as having relative high, medium, and low capabilities of depositing EPA and DHA in their muscle tissue after being reared on the mainly soy/flax oil containing diet. However, none of these genes showed a positive correlation with the high conversion/deposition group.

We report performance of rainbow trout (Oncorhynchus mykiss) fed a balanced dietary mix of plant proteins supplemented with either fish bone meal (FBM) derived from Alaskan seafood processing byproducts or dicalcium phosphate. Seven experimental diets were formulated to contain two levels of dicalcium phosphate or two levels of two different kinds of FBM in all plant-protein (APP) based diets as follows: Diet 1, FM based; Diets 2 and 3, APP diets with low or high dicalcium phosphate; Diets 4 and 5, APP diets with 4% or 8% low phosphorus FBM; and Diets 6 and 7, APP diets with 2.7% or 5.4% high phosphorus FBM. The limiting amino acids methionine and lysine, as well as the amino sulfonic acid taurine, were added to the APP diets at appropriate concentrations. Triplicate groups of juvenile rainbow trout (average weight 31.5 g) were fed one of the seven experimental diets for 12 weeks. Negative effects on growth performance and feed utilization were observed in the fish fed both kinds of FBM or the low level of dicalcium phosphate supplemented to APP diets. Fish fed high levels of dicalcium phosphate showed growth performance and feed utilization that was not significantly different from the control group indicating that FM may be completely replaced by plant proteins with appropriate dietary supplements. Significantly decreased ash levels and increased lipid content were observed in fish fed diets supplemented with FBM or dicalcium phosphate at low levels. Whole-body phosphorus level was not significantly different between controls and fish fed APP diets supplemented with dicalcium phosphate whereas phosphorus levels were significantly lower in FBM fed fish. The apparent digestibility coefficients (ADC) of protein and phosphorus were lower in the control diet than diet 3. The digestibility of the two kinds of FBM was not different. Therefore, the results indicate that total replacement of dietary FM solely by plant proteins could be possible in rainbow trout with no apparent reduction in growth performance or feed utilization when a balanced mix of plant protein ingredients is properly supplemented with highly available inorganic phosphate, limiting amino acids and taurine. Maintenance of the body Ca/P ratio close to 1 was also found in rainbow trout although the differences in diets were considerable. Alaskan FBM could be used in fish feeds as a supplemental calcium source but not as the primary source of phosphorus because of the low bioavailability of phosphorus to fish in these diets.

Diet formulation and manufacture are exercises in compromise between the ideal and the practical. The perfect feed formulation that meets the nutritional needs of an animal or fish must always be modified to be less than ideal so that it can be manufactured. Diet formulation and manufacture are not independent activities. When feeds are formulated, the pelleting characteristics of mixtures are just as important as the nutritional content of the mixture. Production diets must be economical to manufacture, ship, store, and deliver to the fish. Pellets must remain intact in water until fish consume them. This ensures adequate intake of nutrients that might otherwise leach out of the pellets and minimize water pollution caused by disintegrating pellets. Thus, the way in which feed ingredients are chosen, prepared, combined, and processed is influenced by many factors, and compromise between the ideal and the practical is a necessity requiring a solid foundation of knowledge and experience. Rising concerns about the effects of fish farming on the aquatic environment, coupled with concerns about the dependence of fish feeds on fish meal produced from fully utilized or over-utilized wild fish stocks, have also influenced fish feed formulation and manufacture.

2010年6月21日受理(Received. June 21. 2010) *1 Hagerman Fish Culture Experiment Station, University of Idaho, 3059F National Fish Hatchery Road, Hagerman, ID 83332, USA E-mail: Wendy_Sealey@fws.gov; WS present address: USFWS, Bozeman Fish Technology Center, 4050 Bridger Canyon Road, Bozeman, MT 59715, USA *2 Trout Grains Program, United States, Department of Agriculture, Agricultural Research Service, 3059F National Fish Hatchery Road, Hagerman, ID 83332, USA *3 Aquaculture & Pathology Consulting, Bozeman, MT 59715, USA Abstract:Higher inclusion levels of plant-based feedstuffs in diets for rainbow trout necessitate identification of methods to mitigate the negative effects on fish growth and health. Thus, an increasing number of novel and re-purposed dietary supplements are becoming commercially available to counteract the anti-nutritional effects of plant-based ingredients. Specifically, probiotic bacteria, which have previously been primarily investigated for their anti-pathogenic effects in fish, are now promoted to aid in the utilization of plant-based diets and digestive tract health. Additionally, dietary supplementation of commercially produced anti-inflammatory antibodies used to reduce gastrointestinal tract inflammation in terrestrial animals may also have potential to improve digestive tract health and performance of aquatic animals fed plant-based diets. The present paper describes two studies conducted at the Hagerman Fish Culture Experiment Station that investigated the ability of dietary probiotics and anti-phospholipase A2 antibody to improve performance of rainbow trout fed soybean meal-based diets.