Showing papers in "Aquaculture Nutrition in 2013"
TL;DR: The optimal dietary carbohydrate and lipid contents for fingerling blunt snout bream were 291.7 and 81.4 g kg−1, respectively, with a corresponding dietary CHO/L ratio of 3.58.
Abstract: This study aimed to investigate the optimum dietary carbohydrate/lipid (CHO/L) ratio for fingerling blunt snout bream Megalobrama amblycephala (average initial weight: 6.61 ± 0.03 g). Six isonitrogenous and isoenergetic diets were formulated to contain various CHO/L ratios ranging from 1.62 to 24.20. Each diet was tested in four replicates for 10 weeks. Specific growth rate (SGR), feed conversion ratio and nitrogen and energy retention all improved significantly (P 0.05) as dietary CHO/L ratios ranged from 2.45 to 5.64. Hepatosomatic index increased significantly (P 0.05) among all the treatments, while liver glycogen content increased significantly (P < 0.05) with increasing CHO/L ratios. High dietary carbohydrate enhanced the activities of liver hexokinase, pyruvate kinase and glucose-6-phosphate dehydrogenase but did not induce hyperglycaemia. Based on the second-order polynomial regression analysis of SGR, the optimal dietary carbohydrate and lipid contents for fingerling blunt snout bream were 291.7 and 81.4 g kg−1, respectively, with a corresponding dietary CHO/L ratio of 3.58.
106 citations
TL;DR: Pacific white shrimp Litopenaeus vannamei were fed either control diet or one of six dietary astaxanthin concentration diets for 56 days in 35 tanks, and shrimp-fed AX125 and AX150 diets had higher weight gain, specific growth rate, total antioxidant status and lower superoxide dismutase, catalase, and CAT expression levels than shrimp fed control diet.
Abstract: Pacific white shrimp Litopenaeus vannamei (1050 individuals with initial weight of 1.01 ± 0.001 g) were fed either control diet or one of six dietary astaxanthin (AX) concentration (25, 50, 75, 100, 125 and 150 mg kg−1) diets for 56 days in 35 tanks (30 shrimp per tank). After 56 days of culture, shrimp-fed AX125 and AX150 diets had higher (P < 0.05) weight gain, specific growth rate, total antioxidant status and lower (P < 0.05) superoxide dismutase (SOD), catalase (CAT) than shrimp fed control diet. After low dissolved oxygen stress for 1 h, survival rate of shrimp fed AX75, AX100, AX125 and AX150 diets was higher (P < 0.05) than that of shrimp fed control diet. Hypoxia inducible factor-1α (HIF-1α), cytosolic manganese superoxide dismutase (cMnSOD) and CAT mRNA expression levels of shrimp fed seven diets were significantly down-regulated under hypoxia than under normoxia, but their expression levels were higher under hypoxia in shrimp fed AX-supplemented diets than in shrimp fed control diet. About 70-kDa heat-shock protein (Hsp70) mRNA expression level of shrimp fed seven diets was significantly up-regulated under hypoxia than under normoxia, but its expression level was lower under hypoxia in shrimp fed AX-supplemented diets than in shrimp fed control diet.
81 citations
TL;DR: Dietary supplementation of FOS could confer benefits on growth performance, intestinal digestive and absorptive ability, histology of fingerling Megalobrama amblycephala.
Abstract: A feeding trial was conducted to investigate the effects of dietary fructooligosaccharide (FOS) on growth performance, body composition, intestinal enzymes activities and histology of fingerling Megalobrama amblycephala. A total of 1200 fish (1.42 ± 0.01 g) were fed diets containing graded levels of FOS (0, 0.5, 1, 2, 4 and 8 g kg−1 diet) for 8 weeks in a recirculating system indoor. The weight gain, specific growth rate (SGR) and survival rate were all improved in dietary supplementation of FOS fed fish. Increasing FOS levels resulted in both higher whole-body lipid and lower moisture contents, whereas ash and protein contents showed no significant differences among all the treatments. Intestinal amylase, protease, Na+, K+-ATPase, alkaline phosphatase, γ-glutamyl transpeptidase and creatine kinase activities all increased with dietary FOS levels up to 4 g kg−1 (P < 0.05). Transmission electron microscopy analysis indicated that microvilli length in the mid-intestine was significantly increased with increased dietary FOS levels (P < 0.05). In conclusion, dietary supplementation of FOS could confer benefits on growth performance, intestinal digestive and absorptive ability, histology of fingerling Megalobrama amblycephala.
78 citations
TL;DR: Results from this study demonstrate that enrichment media currently in use are not effective for enhancing the nutritional quality of rotifers, compared with natural zooplankton.
Abstract: The objective of this study was to examine the biochemical composition of intensively reared rotifers after enrichment with three commonly used enrichment media, Multigain, Ori-Green and DHA-enriched freshwater algae Chlorella, using standard enrichment protocols at a local cod larvae producer and compare it with that of natural zooplankton from Lofilab AS, a cod larvae producer using semi-intensive rearing techniques. Unenriched rotifers were analysed to examine whether the enrichment procedures were successful in increasing the content of essential nutrients to level requirements for marine fish larvae. Neither total lipids nor proteins were affected by enrichment. Unenriched rotifers were significantly lower in highly unsaturated fatty acids (HUFAs) and significantly higher in linoleic acid (LA, C18:2, n-6), than were zooplankton. Enrichment with Chlorella and Multigain increased the HUFAs significantly, while they were slightly reduced after enrichment with Ori-Green. Total amino acids and mineral content were unaffected by enrichment. Zooplankton was rich in taurine and selenium, whereas rotifers were devoid of it, both prior to and after enrichment. Using zooplankton as a reference for the nutritional requirements of marine fish larvae, results from this study demonstrate that enrichment media currently in use are not effective for enhancing the nutritional quality of rotifers.
75 citations
TL;DR: This paper summarizes studies regarding the move towards high soy diets concerning manipulation of ingredients and nutrient profiles to maintain balanced feed formulations.
Abstract: The production of the Pacific white shrimp (Litopenaeus vannamei) has expanded to the point of being the most widely cultured species of shrimp. One of the advantages of this species is its acceptance of a wide variety of feed formulations including plant-based feeds. Given the increases in ingredient costs, particularly fish meal, there is considerable interest in the use of alternative feed formulations for cultured species. Given that soybean meal is one of the most widely available protein sources for which production can be expanded, the move to soy-based diets is inevitable. The successful use of alternative feed ingredients for shrimp production depends on a number of factors. This paper summarizes studies regarding the move towards high soy diets concerning manipulation of ingredients and nutrient profiles to maintain balanced feed formulations.
71 citations
TL;DR: Valine improved fish growth, digestive and absorptive ability, and the trends of muscle GOT activity and plasma ammonia content were opposite.
Abstract: This study investigated the effects of valine on growth, intestinal enzyme activities and microflora in juvenile Jian carp (Cyprinus carpio var. Jian). A total of 1200 fish with an average initial weight of 9.67 ± 0.03 g were fed diets containing 5.3 (unsupplemented control), 8.7, 11.8, 14.9, 18.7 and 20.1 g valine kg−1 diet for 60 days. Results indicated that the specific growth rate, feed efficiency, body protein and lipid content of fish were significantly improved by the dietary valine (P < 0.05). The hepatopancreas weight and activities of trypsin, amylase, lipase, chymotrypsin, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) took the similar trends. Similarly, the optimum levels of dietary valine induced increases in the intestinal length, weight, folds height and activities of alkaline phosphatase, gamma-glutamyl transpeptidase and creatine kinase. In contrast, the trends of muscle GOT activity and plasma ammonia content were opposite. Intestinal Aeromonas, Escherichia coli, Lactobacillus and Bacillus were changed by dietary valine supplementations. The dietary valine requirement for Jian carp (9.67–76.4 g) based on SGR was 13.7 g valine kg−1 diet (4.0 g valine 100 g−1 CP). Together, these results indicated that valine improved fish growth, digestive and absorptive ability.
67 citations
TL;DR: Results clearly indicate that inulin and FOS improved the intestinal absorption of Ca and that the increased amount was predominantly incorporated into bone tissue.
Abstract: The objectives of the present study were to investigate the effects of inulin and fructooligosaccharides (FOS) on growth performance, whole body and fillet chemical composition and intestinal microbiota of rainbow trouts reared under fish farming conditions. Trouts fed inulin- or FOS-containing diets (5 and 10 g kg−1) exhibited significant (P = 0.030) body weight gain improvements compared with controls. An increase in gross energy (P = 0.044) and Ca content (P = 0.034) in the whole body of trouts was observed for prebiotic treatments. A decrease in crude protein content (P = 0.009) and a tendency to increase total lipid and gross energy contents (P = 0.090 and P = 0.069, respectively) were detected in the fillet tissue for prebiotic treatments. These results clearly indicate that inulin and FOS improved the intestinal absorption of Ca and that the increased amount was predominantly incorporated into bone tissue. Inulin reduced (P = 0.027) the intestinal population of Vibrio spp. in the distal region to such an extent that no viable counts were detected. The presence of Flavobacterium spp. was not detected in any group, and the numbers of Aeromonas spp., Pseudomonas spp. and Gram-positive bacteria were not affected (P > 0.05).
63 citations
TL;DR: Iodine, selenium and vitamin D concentrations, all declined during the time period; simultaneously, a reduction in marine ingredients in feeds has occurred, and cadmium concentrations were twofold higher in South American FMs, and increased in feeds from 2000 to 2010.
Abstract: This article presents data on commercial, Norwegian fish feeds from 2000 to 2010, including elements, additives, some selected vitamins and a range of environmental contaminants. Iodine, selenium and vitamin D concentrations, all declined during the time period; simultaneously, a reduction in marine ingredients in feeds has occurred. Still, the feeds fulfilled known fish nutrient requirements. Arsenic (As) in the feed was fitted with a polynomial regression with peak concentrations in 2004, correlating with fishery landings of blue whiting (Micromesistus poutassou), a reduction species with high content of As. A polynomial regression was also significant for mercury, which peaked in 2005 and was correlated to fish meal (FM) inclusion in the feeds. Residues of the pesticide DDT and its metabolites, chlordane and toxaphene, as well as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers and sum dioxins and dioxin-like PCBs, all decreased during this time period. These positive changes in undesirable substances can likely be attributed to the increasing replacement of marine ingredients with plant ingredients, as well as the increased use of South American fish oils rather than North Atlantic ones. On the other hand, cadmium concentrations were twofold higher in South American FMs, and increased in feeds from 2000 to 2010.
62 citations
TL;DR: Dietary oxidized lipid increased the oxidative stress condition of fish, but more than 400 mg VC kg−1 of dietary supplement improved growth and health of juvenile red sea bream.
Abstract: A 50-day feeding trial was conducted to determine the effects of dietary oxidized fish oil (OFO) and vitamin C (VC) on growth and oxidative stress in juvenile red sea bream. Test diets were formulated with 2 degrees of peroxide value (23 and 29 meq kg−1) combined with 3 levels of VC (0, 400 and 800 ppm). No significant difference was found on growth performance between fish fed OFO with 400 or 800 mg VC and the control group that fed a diet with fresh fish oil after 50 days. However, fish fed OFO without VC supplement indicated significantly poor growth than the control group. Liver and muscle thiobarbituric acid reactive substances were reduced by increased VC intake of fish. Fish fed diets containing low OFO with 400 and 800 mg VC, high OFO with 800 mg VC, and fresh fish oil are allocated in the zone of high resistance against oxidative stress together with low oxidative stress condition. On the other hand, no VC supplemented group was under the highest oxidative stress condition. In conclusion, dietary oxidized lipid increased the oxidative stress condition of fish, but more than 400 mg VC kg−1 of dietary supplement improved growth and health of juvenile red sea bream.
62 citations
TL;DR: An 8-week feeding trial was conducted to establish the dietary vitamin E requirement of juvenile cobia and indicated that fish fed the diets supplemented vitamin E had significantly higher specific growth rate, protein efficiency ratio, feed efficiency and survival rate than those fed the basal diet.
Abstract: An 8-week feeding trial was conducted to establish the dietary vitamin E requirement of juvenile cobia. The basal diet was supplemented with 10, 20, 30, 40, 60, 120 mg vitamin E kg−1 as all-rac-α-tocopheryl acetate. The results indicated that fish fed the diets supplemented vitamin E had significantly higher specific growth rate, protein efficiency ratio, feed efficiency and survival rate than those fed the basal diet. It was further observed that vitamin E concentrations in liver increased significantly when the dietary vitamin E level increased from 13.2 to 124 mg kg−1. Fish fed the basal diet had significantly higher thiobarbituric acid-reactive substances concentrations in liver than those fed the diets supplemented vitamin E. Fish fed the diets supplemented with 45.7 and 61.2 mg kg−1 vitamin E had significantly higher red blood cell and haemoglobin than those fed the basal diet, while fish fed the diets supplemented with 61.2 and 124 mg kg−1 vitamin E had higher immunoglobulin concentration than those fish fed the basal diet. Lysozyme and superoxide dismutase were significantly influenced by the dietary vitamin E level. The dietary vitamin E requirement of juvenile cobia was established based on second-order polynomial regression of weight gain and lysozyme to be 78 or 111 mg all-rac-α-tocopheryl acetate kg−1 diet, respectively.
61 citations
TL;DR: Administration of 2.5 g kg−1 of the Optimun dietary nucleotide formula is recommended to promote growth and immunity as well as to enhance stress responses of Caspian brown trout.
Abstract: A feeding trial was conducted to evaluate the effects of Optimun, a commercial nucleotide (NT) product, on the growth, haemato-immunological and serum biochemical parameters and stress responses of Caspian brown trout fingerlings (average initial weight of 12.26 g). A basal diet was supplemented with levels of 0 (control), 1.5, 2.5, 3.5 and 5 g NT kg−1 to formulate five experimental diets. After 8 weeks of feeding trial, fish fed diet with 2.5 g NT kg−1 had the highest final weight compared with other treatments. The fish fed diets with 2.5 g NT kg−1 had higher blood protein, albumin, albumin/globulin ratio, red blood cells, white blood cells and lymphocyte content and lower alkaline phosphatase. The lysozyme activity in serum was found to be significantly (P < 0.05) greater in fish fed diet with 2.5 g NT kg−1. Concerning both stressors (confinement and salinity stress), fish fed diet with 2.5 g NT kg−1 had lower plasma cortisol and glucose levels. Thus, administration of 2.5 g kg−1 of the Optimun dietary nucleotide formula is recommended to promote growth and immunity as well as to enhance stress responses of Caspian brown trout.
TL;DR: The study suggests that LAB may modulate intestinal inflammation; however, the role of the microbiota in the aetiology of enteritis in fish still requires further study.
Abstract: The aim of this study was to evaluate the role of the intestinal microbiota in soybean meal enteritis. Three groups of Atlantic salmon (Salmo salar) were fed for 35 days with different diets: a control diet (CD) containing 510 g kg �1 fishmeal, diet 1 (D1) containing 378 g kg �1 of soybean meal and diet 2 (D2) containing D1 supplemented with two viable lactic acid bacteria (LAB). As expected, the fish fed with D1 showed clear signs of distal intestinal inflammation during the study compared with the fish fed CD. For the fish fed with D2, the addition of LAB diminished the inflammation at day 28, but did not abolish it. Microbiological analysis demonstrated that specific bacterial groups were not correlated with the development of enteritis, but were correlated with the three diets. Microbacterium, Pseudomonas, Lactococcus lactis sp. cremoris and Aeromonas VIa were correlated with the CD, Aeromonas VIb and Sporosarcina aquimarina were correlated with D1, and Alcaligenes, Acinetobacter, L. lactis sp. lactis and Carnobacterium maltaromaticum were correlated with D2. Shewanella was not affected by the diet and was present in all fish intestines. Our study suggests that LAB may modulate intestinal inflammation; however, the role of the microbiota in the aetiology of enteritis in fish still requires further study.
TL;DR: A meta-analysis of available data on dose response to dietary phosphorus (P) in fish from over 70 feeding trials reported in 64 published studies showed that estimated minimal dietary P level varies with the response criterion and that estimates should preferably be expressed in terms of available P than in Terms of total P.
Abstract: A meta-analysis of available data on dose response to dietary phosphorus (P) in fish from over 70 feeding trials reported in 64 published studies covering over 40 species of fish was performed. Broken-line regression was used to model the data sets. The meta-analysis showed that estimated minimal dietary P level varies with the response criterion and that estimates should preferably be expressed in terms of available P than in terms of total P. Estimates based on whole-body P concentration (4.7 g available P kg-1 dry matter, DM) or vertebral P (5.2 g available P kg-1 DM) were greater than that for maximizing somatic weight gain (WG) (3.5 g available P kg-1 DM) or plasma P concentration (2.8 g available P kg-1 DM). P content of fish varies linearly with body mass (3.6 g kg-1 live weight). Use of ingredients rich in P or of diets with high basal P content or high levels of water P concentration can affect the estimations. Among the different response criteria tested, WG was found to be the most reliable and whole-body P concentration to be the most stringent criterion to estimate P requirement of a given fish species. Expressing available P requirement as g P per unit DM or digestible energy (DE) in the diet was equally effective, but expressing in terms of g P intake per kg BW0.8 per day would be more precise.
TL;DR: Astaxanthin is likely an important dietary component for hatchery or laboratory reared red king crab juveniles, and should be considered for aquaculture and other rearing of this and possibly other crustacean species.
Abstract: We conducted large-scale production trials in Seward, Alaska, USA to investigate effects of dietary astaxanthin supplementation on survival, growth and shell colouration of recently settled juvenile (C1–C4) red king crabs (Paralithodes camtschaticus). We supplemented a control diet of commercial crustacean feeds with astaxanthin, and fed these diets to juvenile king crabs at densities of 2000 and 4000 crabs m−2 for 56 days. We assessed survival and growth by counting crabs and individually measuring carapace width and weighing crabs at the start and end of the experiment, and quantified crab colour (hue, saturation, brightness) in digital photographs. Diets containing astaxanthin had higher survival, suggesting that astaxanthin may provide nutritional or immune system benefits. Crabs had lower hue, higher saturation and lower brightness values when fed diets containing astaxanthin, suggesting that red king crab colouration is plastic and responds to diet. Astaxanthin is likely an important dietary component for hatchery or laboratory reared red king crab juveniles, and should be considered for aquaculture and other rearing of this and possibly other crustacean species.
TL;DR: The authors thank Dr. Richard Smullen (Ridley AgriProducts Pty Ltd, Australia) and Dr. Lucky Inturrisi (Cargill Ltd) for kindly donating the raw materials used for experimental feed preparation.
Abstract: Research support from Nuseed (Nuseed Global, Laverton, Victoria, Australia) is gratefully acknowledged. The authors are also grateful to Dr. Richard Smullen (Ridley AgriProducts Pty Ltd, Australia) and Dr. Lucky Inturrisi (Cargill Ltd, Australia) for kindly donating the raw materials used for experimental feed preparation.
TL;DR: Results showed that under a clear-water condition, the dietary levels of FO in practical diets for L. vannamei have a significant impact on the amount of FM that can be replaced by SPC.
Abstract: This work aimed to determine whether a minimum provision of marine oil in practical diets for Litopenaeus vannamei is required when replacing fish meal (FM) by soy protein concentrate (SPC). The study consisted of three growth experiments conducted in 500-L tanks with 70 shrimp m−2. In experiment #1, FM was progressively replaced by SPC as fish oil (FO) levels increased with a consistent input of whole squid meal (WSM). In experiment #2, FM was replaced by SPC under two levels of FO (10 or 20 g kg−1) without the presence of a feeding effector. In experiment #3, three dietary levels of krill meal (KRL) and WSM (5, 10 and 20 g kg−1) were included in a basal diet containing SPC and low levels of FM. Results showed that under a clear-water condition, the dietary levels of FO in practical diets for L. vannamei have a significant impact on the amount of FM that can be replaced by SPC. As much as 31% replacement of FM/SPC was possible with 20 g kg−1FO. Whenever dietary fat was adjusted by using FO as a lipid source, complete replacement of FM by SPC was achieved with no negative effect on shrimp growth.
TL;DR: In this paper, a feeding trial was conducted to determine the dietary methionine requirement of juvenile golden pompano (initial body weight 12.40 ± 0.02 grams), and six diets were formulated with six graded levels of methions: 8.6, 9.2, 10.4, 11.5, 13.2 and 14.5.
Abstract: A feeding trial was conducted to determine the dietary methionine requirement of juvenile golden pompano (initial body weight 12.40 ± 0.02 g). Six diets were formulated with six graded levels of methionine (8.6, 9.2, 10.4, 11.5, 13.2 and 14.5 g kg−1). Each diet was randomly assigned to triplicate groups of 20 juvenile fish in seawater floating net cages (1.0 m × 1.0 m × 1.5 m). Fish were fed twice daily (08:30 and 16:30) to apparent satiation for 56 days. Weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), feed efficiency (FE), nitrogen retention efficiency (NRE), proximate body composition, morphometry and haematology were significantly (P < 0.05) affected by the dietary methionine levels. WG, SGR and FE increased with increasing levels of methionine up to 13.2 g kg−1 diet (P < 0.05) and remained nearly the same thereafter. NRE also increased with increasing levels of methionine up to 13.2 g kg−1 diet (P < 0.05) and remained nearly the same thereafter. Linear regression analysis on WG and NRE indicated that the recommended optimum dietary methionine levels for optimal growth of juvenile pompano were 10.6 and 12.7 g kg−1 diet, respectively, corresponding to 24.6 and 29.5 g kg−1 dietary protein, respectively, so the level of dietary methionine should be between 10.6 and 12.7 g kg−1 diet, corresponding to 24.6–29.5 g kg−1 dietary protein. Additionally, the estimated requirements for the other essential amino acids were calculated from A/E ratios of whole-body amino acid profile based on the methionine requirement determined from the present experiment.
TL;DR: It is suggested that the supplementation of feed with TVH that has been processed under suitable conditions can improve feed palatability and growth performance when utilizing alternative protein sources in Asian seabass diets.
Abstract: Skipjack tuna viscera hydrolysate (TVH) was produced by enzymatic hydrolysis using alcalase. A study of the effect of time and enzyme concentration was performed and formed the basis for preparing TVH with the desired degree of hydrolysis (DH). An enzyme to substrate ratio of 5 g kg−1 (TVH A1) and 16.4 g kg−1 (TVH A2) at pH 8.0 with a temperature of 50 °C, and hydrolysis time of 60 min were found to be optimal conditions to obtain hydrolysis of 42.9% and 62.9%, respectively. Both TVH A1 and TVH A2 were analysed for chemical and amino acid composition and peptide size. The effectiveness of TVH at different DH as feeding attractants was estimated in a feeding trial at different inclusion levels. Ten experimental diets, including a fish meal-based reference diet, were fed to Asian seabass for 28 days. Fish fed the diet supplemented with 30 g kg−1 of TVH A2, and the reference diet showed the highest feed intake (P < 0.05). The growth performance of fish fed diets supplemented with TVH was slightly higher than those of fish fed the control diet, but the reference group showed a significantly higher growth rate (P < 0.05). These findings suggest that the supplementation of feed with TVH that has been processed under suitable conditions can improve feed palatability and growth performance when utilizing alternative protein sources in Asian seabass diets.
TL;DR: In this article, an adult Atlantic salmon (Salmo salar; approximately 800 g start weight) were fed diets with a high replacement of fish meal (FM) with plant proteins (70% replacement), and either fish oil (FO) or 80% of the FO replaced by olive oil (OO), rapeseed oil (RO) or soybean oil (SO) during 28 weeks in triplicate.
Abstract: Adult Atlantic salmon (Salmo salar; approximately 800 g start weight) were fed diets with a high replacement of fish meal (FM) with plant proteins (70% replacement), and either fish oil (FO) or 80% of the FO replaced by olive oil (OO), rapeseed oil (RO) or soybean oil (SO) during 28 weeks in triplicate. Varying the lipid source only gave non-significant effects on growth and final weight. However, a significantly reduced feed intake was observed in the SO fed fish, and both feed utilization and lipid digestibility were significantly reduced in the FO fed fish. Limited levels of dietary 18:3n-3, precursor to EPA and DHA, resulted in no net production of EPA and DHA despite increased mRNA expression of delta-5-desaturase and delta-6-desaturase in all vegetable oil fed fish. Net production of marine protein, but not of marine omega-3 fatty acids, is thus possible in Atlantic salmon fed 80% dietary vegetable oil and 70% plant proteins resulting in an estimated net production of 1.3 kg Atlantic salmon protein from 1 kg of FM protein. Production of one 1 kg of Atlantic salmon on this diet required only 800 g of wild fish resources (Fish in - Fish out < 1).
TL;DR: Results of this study suggest increasing the dietary lipid level from 65 to 125 could not induce protein-sparing action in golden pompano, and the suitable dietary protein and lipid levels for juvenileGolden pompano reared in net pens should be 450–490 and 65 g kg−1.
Abstract: A feeding trial was conducted to determine the suitable dietary protein and lipid levels for juvenile golden pompano Trachinotus ovatus reared in net pens. Ten test diets were formulated at five levels of crude protein (330, 370, 410, 450 or 490 g kg−1) and two levels of crude lipid (65 or 125 g kg−1). Golden pompano fingerlings (initial body weight 4.7 g ind−1) were fed the test diets for 8 weeks. Weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), nitrogen retention efficiency (NRE), energy retention efficiency (ERE), condition factor (CF), hepatosomatic index (HSI), body protein content and total nitrogen waste (TNW) were dependent on both dietary protein and lipid levels. Feed intake (FI) and viscersomatic index (VSI) were dependent on dietary protein level, while body lipid content was dependent on dietary lipid level. Weight gain increased with increasing the dietary protein level (at the same lipid level) but was lower at the dietary lipid level of 65 g kg−1 than at 125 g kg−1 (at the same protein level). Fish fed at the dietary protein levels of 460–490 g kg−1 had higher WG and lower FCR than at 330–410 g kg−1. Energy retention efficiency tended to increase with increasing the dietary protein level from 330 to 410 g kg−1, while no significant difference was found in nitrogen retention efficiency between the dietary protein levels (at the same lipid level). Results of this study suggest increasing the dietary lipid level from 65 to 125 g kg−1 could not induce protein-sparing action in golden pompano, and the suitable dietary protein and lipid levels for juvenile golden pompano reared in net pens should be 450–490 and 65 g kg−1.
TL;DR: The results suggest that the diet containing 450 g kg−1 protein and 50 g–g–kg–1 lipid with a P/E ratio of 29.1 mg protein kJ−1 is optimal for growth and feed utilization of P. ussuriensis fingerlings under the experimental conditions used in the study.
Abstract: An 8-week feeding trial was conducted to investigate the optimum dietary protein and lipid levels for growth, feed utilization and body composition of Pseudobagrus ussuriensis fingerlings (initial weight: 3.40 ± 0.01 g). Twelve diets containing four protein levels (350, 400, 450 and 500 g kg−1 crude protein) and three lipid levels (50, 100 and 150 g kg−1 crude lipid) were formulated. Fish were randomly allotted to 36 aquaria (1.0 × 0.5 × 0.8 m) with 25 fish to each glass aquarium. Fish were fed twice daily (08:00 and 16:00) to apparent satiation. The results showed that weight gain and specific growth rate (SGR) decreased with increasing dietary lipid level from 50 to 150 g kg−1 at the same dietary protein level. Fish fed the diets containing 150 g kg−1 lipid exhibited higher feed conversion ratio (P < 0.05), lower protein efficiency ratio (PER) and nitrogen retention efficiency (NRE) relative to fish fed the diet containing 50 and 100 g kg−1 lipid. Weight gain and SGR significantly increased with increasing dietary protein from 350 to 450 g kg−1 at the same dietary lipid level, and even a little decline in growth with the further increase in dietary protein to 500 g kg−1. Daily feed intake, NRE and PER were significantly affected by both dietary protein and lipid levels (P < 0.05) and tended to decrease with increasing dietary protein and lipid levels. Whole-body protein content increased as protein levels increased and lipid levels decreased. Whole-body lipid and muscle lipid content increased with increasing dietary lipid level, and decreased with increasing dietary protein at each lipid level. There was no significant difference in condition factor and viscerosomatic index among fish fed the diets. Hepatosomatic index was affected by dietary lipid level (P < 0.05), and increased with increasing dietary lipid level at the same protein level. These results suggest that the diet containing 450 g kg−1 protein and 50 g kg−1 lipid with a P/E ratio of 29.1 mg protein kJ−1 is optimal for growth and feed utilization of P. ussuriensis fingerlings under the experimental conditions used in the study.
TL;DR: Results show that a low replacement level (15%) of fish meal with Nori improves growth and feed utilization while oxygen consumption and amount of oxygen consumed per gram protein gain are significantly decreased.
Abstract: A 10-week feeding experiment was conducted in a respirometric system to evaluate the suitability of red alga Nori (Porphyra yezoensis) as a partial replacement for fish meal in intensively fed Nile tilapia. Diets were formulated to be iso-nitrogenous and iso-energetic and to replace 0%, 15% and 30% fish meal with Nori, P. yezoensis. No statistically significant differences in growth or feed utilization between the control diet and either Nori diet were found. Tilapia fed on Nori 15 increased their body mass by 415%, those fed the control diet by 341% and fish fed Nori 30 by 317% over the experimental period. Nori 15 fed fish showed the best feed utilization, highest metabolic growth rate and significantly lower oxygen consumption rates than the control. Both Nori supplemented groups (Nori 15: 4.1 g O2 g−1 protein gain and Nori 30: 3.9 g O2 g−1 protein gain) used less oxygen per gram of protein gain compared to fish fed the control diet (5.4 g O2 g−1 protein gain). Our results show that a low replacement level (15%) of fish meal with Nori improves growth and feed utilization while oxygen consumption and amount of oxygen consumed per gram protein gain are significantly decreased.
TL;DR: Results of the present study appear to indicate that 40% FM can be replaced by SBM in practical feeds of Chinese sucker without causing reduction in growth and protein utilization.
Abstract: Six isonitrogenous diets (420 g kg−1 crude protein on dry matter basis) with six levels of soybean meal (SBM) inclusion (0, 112, 225, 336, 449 and 560 g kg−1) in substitution of fish meal (0%, 20%, 40%, 60%, 80% and 100%) were evaluated in Chinese sucker of 1.81 ± 0.01 g initial weight for 8 weeks. There existed a significant difference (P < 0.001) in fish weight gain, feed conversion ratio, feed intake, protein efficiency ratio and specific growth rate when the replacement level for fish meal protein was increased from 40% to 60%, indicating that up to 40% of fish meal protein could be replaced with SBM protein without causing reduction in growth and protein utilization. Lipid contents in the Chinese sucker body decreased significantly (P < 0.001) as dietary SBM increased. Digestive enzyme activities in the intestine and hepatopancreas of the fish were significantly different (P < 0.001) as the SBM protein replacement level was increased. Results of the present study appear to indicate that 40% FM can be replaced by SBM in practical feeds of Chinese sucker.
TL;DR: The neutral and thermostable phytase of Bacillus subtilis E20 is suitable for aquafeed, and it is able to improve the nutritional utilization, resulting in enhanced shrimp growth and reduced feed costs.
Abstract: To produce a thermostable and neutral phytase (phy) of Bacillus subtilis E20 in Escherichia coli HMS174 and evaluate its efficiency in improving growth performance The phy C of B subtilis E20 was expressed in E coli HMS 174, and then the 42-kDa recombinant phy C was purified by Ni-NAT and analysed by SDS–PAGE The recombinant phy C had optimal ranges of pH of 6 ~ 7 and temperature of 50 ~ 60 °C A thermostability analysis showed that the enzyme is a thermostable phytase, and around 33% of residual activity was detected after being incubated at 90 ~ 100 °C for 10 min The recombinant phy C-pretreated soybean meal for feed preparation improved white shrimp, Litopenaeus vannamei, growth and feed efficiency Overall, the neutral and thermostable phy C is suitable for aquafeed, and it is able to improve the nutritional utilization, resulting in enhanced shrimp growth and reduced feed costs
TL;DR: The results prove that a simultaneous enrichment in HUFA and PL is possible using enrichment diets combining H UFA- and PL-rich products in short-term (4 h) incubations and particularly interesting was the enrichment efficiency shown by the marine lecithin, which enabled the enhancement of the PL fraction of Artemia metanauplii and, importantly, also their HU FA with a remarkable 13% DHA of total fatty acids.
Abstract: Highly unsaturated fatty acids (HUFA), like the eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids and polar lipids (essentially phospholipids, PL) have been identified as essential nutrients for common octopus (Octopus vulgaris) paralarvae. However, they are not available in sufficient amounts in live preys as Artemia, making necessary a supplementation of these nutrients previous use. A commercial emulsion, soya liposomes, and marine and soya lecithins were used to supply HUFA and PL to Artemia metanauplii, those being regarded as suitable size preys for octopus paralarvae. Our results prove that a simultaneous enrichment in HUFA and PL is possible using enrichment diets combining HUFA- and PL-rich products in short-term (4 h) incubations. Particularly interesting was the enrichment efficiency shown by the marine lecithin, which enabled the enhancement of the PL fraction of Artemia metanauplii and, importantly, also their HUFA with a remarkable 13% DHA of total fatty acids. Marine lecithin arises as a novel enrichment diet for Artemia and more effective than some commercial products currently used in hatcheries worldwide.
TL;DR: The data showed that MI could improve the growth and antioxidant capacity of fish enterocytes and may be partly due to the enhanced antioxidant status and depressed oxidative damage.
Abstract: This study investigated the effects of myo-inositol (MI) on the growth and antioxidant capacity of carp enterocytes. The enterocytes were incubated in media containing 0, 15, 30, 45, 60 and 75 mg MI L−1 for 96 h. The results indicated that MI could increase cell viability. In addition, the activities of cellular alkaline phosphatase (AKP), gamma-glutamyl transpeptidase (γ-GT), Na+, K+-adenosine trisphosphatase (Na+, K+-ATPase) and creatinkinase (CK) increased with MI supplementation at levels ranging from 15 to 60 mg MI L−1 medium, indicating an improvement in cell differentiation and function. Further, enzymatic antioxidant ability, as measured by total superoxide dismutase (T-SOD), Cu/Zn-SOD, Mn-SOD, catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities, improved with MI supplementation. Finally, cell damage, as indicated by lactic acid dehydrogenase (LDH) activity, malondialdehyde (MDA) content of the medium and cellular protein carbonyls (PC), was all depressed by MI. Correlation analyses showed that cell viability (MTT) was positively related to the antioxidant enzyme activities, but negatively related to cell damage (LDH, MDA and PC). In summary, the data showed that MI could improve the growth of fish enterocytes. This result may be partly due to the enhanced antioxidant status and depressed oxidative damage.
TL;DR: Dietary FM inclusion down to 160 g kg−1 during the seawater phase, concurrent to replacing ~70% of the FO with a suitable plant oil, is not regarded to represent any risk to fish performance, health or quality.
Abstract: By feeding Atlantic salmon diets with 64% of the fish oil (FO) replaced by vegetable oil, and with decreasing fishmeal (FM) inclusion levels from 213, 178 and 143 g kg−1 (accumulated level during the seawater phase) in a full-scale experiment producing 3.1 thousand tonnes fish, no significant negative effects on fish performance, health and product quality were observed. All dietary groups showed, however, moderate intestinal inflammation. Reduced growth and feed efficiency were seen with decreasing fishmeal inclusion levels. Two dietary groups demonstrated net marine protein production, while none of the groups showed net fish production (FIFO ≥1.65) due to the equal low FO inclusion. High plant oil level gave lower fillet level of persistent organic pollutants (POPs) compared with the levels surveyed on the Norwegian market. The study gave predictable incorporation rates of essential n-3 long-chain fatty acids in the fillet. Cooked salmon fillet from all dietary groups showed minor differences in sensory quality. Based on the present full-scale production results, dietary FM inclusion down to 160 g kg−1 (accumulated) during the seawater phase, concurrent to replacing ~70% of the FO with a suitable plant oil, is not regarded to represent any risk to fish performance, health or quality.
TL;DR: The results of this study suggest that the suitable dietary crude protein and crude lipid levels are 480 g kg−1 and 90 gkg−1 for giant croaker reared in net pens.
Abstract: A 50-day feeding trial was conducted to examine the effects of dietary protein and lipid levels on growth, feed utilization, body composition and swimming performance of giant croaker, Nibea japonica. Fish (initial body weight 44.6 g ind−1) were fed ten test diets which were formulated at 5 crude protein levels (360, 400, 440, 480 and 520 g kg−1) and 2 crude lipid levels (90 and 150 g kg−1). In addition, a raw fish diet (fillet of small yellow croaker) served as the reference. The weight gain (WG) increased, whereas the feed intake (FI) and feed conversion ratio (FCR) decreased, with increasing dietary protein level from 360 to 520 g kg−1. At the same dietary protein level, no significant difference was found in the WG between fish fed the diets containing 90 or 150 g kg−1 crude lipid. Fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid exhibited higher WG, nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) but lower nitrogen wastes output (TNW). At the end of the feeding trial, the hepatosomatic index (HSI) and viscerosomatic index (VSI) decreased, whereas the body protein content increased, with increase in dietary protein level. The body lipid content was higher in fish fed at the 150 g kg−1 lipid level than in fish fed at the 90 g kg−1 lipid level. No significant difference was found in the maximum sustained swimming speed (MSS) between fish fed at different dietary protein and lipid levels. The WG, NRE, ERE and condition factor (CF) were higher, whereas the FI, FCR, HSI, VSI and TNW were lower, in fish fed the raw fish diet than in fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. No significant difference was detected in the MSS between fish fed the raw fish diet and diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. The results of this study suggest that the suitable dietary crude protein and crude lipid levels are 480 g kg−1 and 90 g kg−1 for giant croaker reared in net pens.
TL;DR: Based on the results, supplemental dietary phytase, regardless of application methodology, improved the ADCs of nutrients in grass carp, and the pretreatment mode ofphytase application was more effective than spraying at the same phyt enzyme level.
Abstract: The effects of supplemental graded levels of neutral phytase using pretreatment and spraying methods on the apparent digestibility coefficients (ADCs) of protein, minerals and amino acids were investigated in grass carp (Ctenopharyngodon idellus) (mean weight, 20.92 ± 1.04 g). Seven experimental diets were prepared as: no-phytase supplementation (control), pretreatment with phytase dose of 500 U (PP500), 1000 U (PP1000) and 1500 U (PP1500) per kg diet. With spraying method, the phytase was added to feed at the same three grades, namely 500 U (PS500), 1000 U (PS1000) and 1500 U (PS1500) per kg diet. After an 8-week feeding trial, addition of phytase improved the crude protein, crude lipid, dry matter, ash, phosphorus and calcium digestibilities in comparison with the control, especially in the diets where phytase addition level was above 1000 U kg−1 (P < 0.05). Phytase supplementation, both the pretreatment and spraying, significantly enhanced the ADCs of essential amino acid (EAA) and non-essential amino acid. The ADCs of the nutrients were significantly influenced by phytase supplementation methods, supplementation levels and interaction of methods and levels. Based on the results, supplemental dietary phytase, regardless of application methodology, improved the ADCs of nutrients in grass carp, and the pretreatment mode of phytase application was more effective than spraying at the same phytase level. We suggest that the optimal level of phytase pretreatment is 1000 U kg−1 diet, and the best addition level of phytase spraying is 1500 U kg−1 diet or more phytase is required for spraying.