Antarctic Krill Meal Research Articles

Effects of boiling, centrifuging and drying methods on bioactive compounds in Antarctic krill meal

SummaryBoiling, centrifuging and various drying techniques (vacuum freeze‐drying (VFD), vacuum drying (VD), hot‐air drying (HAD) and microwave drying (MWD)) were assessed for their impact on bioactive compounds in Antarctic krill meal. A comparison between the raw and boiling groups revealed a significant degradation and isomerisation of astaxanthin, accompanied by a 1.25‐fold and 1.32‐fold increase in saturated (SFAs) and monounsaturated fatty acids (MUFAs), respectively. Drying was the primary factor responsible for the reduction in phospholipids, α‐tocopherol and polyunsaturated fatty acid (PUFAs), in combination with the increase in thiobarbituric acid‐reactive substances. For different drying methods, it was found that HAD induced severe lipid oxidation. In contrast, the VFD, VD and MWD improved lipid quality, reducing thiobarbituric acid‐reactive substances (TBARS) by 13–22% and increasing phospholipids by 1.08–1.11 times compared to HAD. VD preserved higher levels of bioactive compounds. PLS‐DA analysis identified 13‐cis‐astaxanthin, α‐tocopherol and eleven fatty acids as key indicators for Antarctic krill meal.

Dietary fishmeal substitution with Antarctic krill meal improves the growth performance, lipid metabolism, and health status of oriental river prawn (Macrobrachium nipponense)

Aims to assess the effects of dietary inclusion of Antarctic krill meal (KM), five experimental diets supplemented with graded levels of KM (0 %, FM; 5 %, KM5; 10 %, KM10; 15 %, KM15; 20 %, KM20; 0 %, 13.3 %, 26.7 %, 40.0 %, and 56.7 % replacement fishmeal levels, respectively), were prepared to feed oriental river prawn (Macrobrachium nipponense) (0.20 ± 0.01 g) for 8 weeks. The results revealed significant improvements in weight gain rate (WGR), specific growth rate (SGR), feed conversion rate (FCR), and protein efficiency ratio (PER) at the inclusion of 5 %-20 % KM (P < 0.05). In the KM10 and KM15 groups, the concentrations of hemolymph total protein (TP), albumin (ALB), triglycerides (TG), high-density lipoprotein (HDL), and hepatopancreatic glutathione (GSH) were observed to be significantly higher compared to the FM group (P < 0.05). Conversely, the contents of hepatopancreatic malondialdehyde (MDA), total nitric oxide synthase (TNOS), and inducible nitric oxide synthase (iNOS) were significantly lower in the KM10 and KM15 groups compared to the FM group (P < 0.05). The mRNA expression levels of dorsal protein (dorsal), heat shock protein 60 (hsp60), and myeloid differentiation factor 88 (myd88) in the hepatopancreas in the KM10 group exhibited the lowest level. Additionally, compared to the FM group, the expression levels of fatty acid synthase (fas) and acetyl CoA carboxylase (acc) were significantly upregulated (P < 0.05), while the acyl CoA bindingprotein (acbp), carnitine palmitoyltransferase I (cpt I), and scavenger receptor B I (sr-b I) were significantly downregulated in the KM10 group (P < 0.05). In addition, the results of histopathology sections showed that 5–15 % KM could improve the health status of hepatopancreas and was a safe alternative to fishmeal. Overall, the optimal KM inclusion level in feed was 12.96 % (substituting for 34.60 % fishmeal) based on the quadratic fitting curve calculations of WGR and SGR.

Prevention of the Quality Degradation of Antarctic Krill (Euphausia superba) Meal through Two-Stage Drying.

To achieve a krill meal of high quality, a two-stage drying involving hot-air drying and vacuum drying was investigated. Five experimental groups were established according to the different drying conditions in the second stage, including 95 °C and 101 kPa, 95 °C and 60 kPa, 75 °C and 101 kPa, 75 °C and 60 kPa, and 75 °C and 20 kPa. The results showed that reducing the drying temperature and vacuum pressure in the second stage had a significant impact on the drying characteristics, sensory quality, and bioactive compounds of krill meal. Among all five groups, the drying condition of 75 °C and 60 kPa maintained a high drying rate while preserving a phospholipid content of 30.01 mg/kg and an astaxanthin content of 37.41 mg/kg. It also effectively reduced the isomerization of astaxanthin and the oxidation of unsaturated fatty acids. These results suggested that the two-stage drying method may contribute to the production of high-quality krill meal.

Effects of Antarctic Krill Meal in Diet on Reproductive Performance and Embryo Quality of Eriocheir sinensis.

A 60-day feeding trial was conducted to evaluate the impact of dietary Antarctic krill meal on the reproductive performance and embryo quality of the Chinese mitten crab, Eriocheir sinensis. Three diets were formulated, incorporating varying levels of Antarctic krill meal at 0% (Diet K0), 10% (Diet K10), and 20% (Diet K20), with a control group fed razor clam Sinonovacula constricta. Each diet was randomly assigned to three replicate tanks, each stocked with 5 males and 10 females. Male and female weights were 145.38 ± 8.01 and 102.57 ± 9.73 g, respectively. The results revealed no significant differences in weight gain rate, specific growth rate, and survival rate. However, the hepatopancreatic weight and hepatopancreas index of female crabs in each group decreased, while gonadal weight and gonadosomatic index increased significantly after 60 days, with Diet K20 showing the highest values. Egg production and fecundity of female crabs reached their peak in Diet K20, with no significant differences in reproductive indices among all groups. The phospholipid content in Diet K20 was significantly higher than in the other groups (P < 0.05). Cholesterol contents in Diet K0 and the control group were significantly higher than in Diet K10 and K20 (P < 0.05). No significant differences were observed in egg diameter, egg weight, moisture, crude protein, and crude fat between the groups. The content of C20 : 2 and C20 : 4n6 was highest in Diet K0, with a significant difference compared to Diet K10 (P < 0.05). However, no significant differences were found in the total content of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids among all groups. Based on the research findings, it is recommended that the optimal level of Antarctic krill meal in diets is 20%.

Effects of composite mixture of protein sources in replacing fish meal on nutritional value and flavor quality of Pacific white shrimp (Litopenaeus vannamei)

An 8-week feeding trial was conducted to investigate the effects of fish meal partially or totally replaced with poultry by-product meal (PBM), antarctic krill meal (AKM), corn gluten meal (CGM), cottonseed meal (CM) and rice protein concentrate meal (RPM) on amino acids, fatty acids, nucleotides and volatile compounds of Pacific white shrimp (Litopenaeus vannamei). Results showed that shrimps fed with partial replacement of fish meal (50 %) with AKM and PBM (1:1) significantly increased the content of inosine monophosphate (IMP), the proportion of eicosapentaenoic acid (EPA), n-9 monounsaturated fatty acids (MUFAs), and significantly decreased the content of hypoxanthine (Hx), benzaldehyde, and the proportion of saturated fatty acids (SFAs). Dietary fish meal totally replaced by the whole-plant protein diet resulted in a lower value of essential amino acids to total amino acids (EAA / TAA), n-3 / n-6 PUFAs, and a lower proportion of docosahexaenoic acid (DHA), n-3 polyunsaturated fatty acid (PUFAs). Principal component analysis and hierarchical cluster analysis revealed that shrimps fed diet with fish meal partially replaced by AKM and PBM (1:1) had the most similar volatile compounds profile to the fish meal-based diet. These results indicated that the composite mixture of PBM and AKM (1:1) is an excellent substitution for fish meal in shrimp diets.

Influences of replacing dietary fish meal by Antarctic krill meal on growth performance, immunity and muscle quality of white shrimp Litopenaeus vannamei

The present study was conducted to investigate the effects of Antarctic krill Euphausia superba meal replacing dietary fish meal on the growth performance, immunity and muscle quality of white shrimp Litopenaeus vannamei (initial body weight: 4.080 ± 0.143 g, mean±SD). The replacement levels were designed as 0%, 5%, 15%, 30%, 45%, 60%, 75% and 100%, respectively. After a 52-day feeding trial, results showed that the specific growth rate (P = 0.129) and feed intake (P = 0.217) of shrimp were not significantly affected. Feed conversion ratio (FCR, P = 0.000), protein efficiency ratio (PER, P = 0.000) and protein retention (PR, P = 0.000) were significantly affected with a quadratic positive trend for FCR, a linear and quadratic negative trend for PER and a quadratic negative trend for PR. The total haemocyte count (P = 0.307), respiratory burst (P = 0.168), activities of superoxide dismutase (P = 0.221) and glutathione reductase (P = 0.170) in serum were not significantly affected. While, malondialdehyde content (P = 0.000), acid phosphatase (P = 0.000) and alkaline phosphatase activity (P = 0.000) in serum were significantly decreased both in linear and quadratic trend. The carotenoid content in exoskeleton (P = 0.019) and pH in muscle (P = 0.000) were linearly increased. With the increasing replacement levels, n-3 PUFA content (P = 0.001) in muscle significantly decreased and n-6 PUFA (P = 0.000) increased. The ratio of essential amino acid to total amino acid (P = 0.000) and the inosinic acid content in muscle (P = 0.002) were significantly increased with the dietary replacement levels in a linear trend. In conclusion, Antarctic krill meal can totally replace dietary fish meal without negative impact on the growth of L. vannamei. From the perspective of feed utilization, after the quadratic regression analysis of FCR, PER and PR, the appropriate replacement level of dietary fish meal by krill meal for L. vannamei was 52.78%, 68.50% and 47.41%, respectively (i.e., dietary krill meal level was 13.27%, 17.22%, and 11.92%, respectively).

Growth, fatty acid composition, immune-related gene expression, histology and haematology indices of Penaeus vannamei fed graded levels of Antarctic krill meal at two different fishmeal concentrations

An eight-week feeding trial was conducted to investigate the effect of dietary krill meal inclusion in diets with moderate (12%) and low (6%) fishmeal concentrations for Penaeus vannamei. Inasmuch, eight iso‑nitrogenous and isolipidic diets were formulated to contain 36% crude protein and 5.5% crude lipid. In the moderate-fishmeal diets, krill meal was included at 0, 2, 4 and 6% (called FK12:0, FK12:2, FK12:4 and FK12:6, respectively), likewise in the low-fishmeal diets, krill meal was included at the same concentrations of 0–6% (called FK6:0, FK6:2, FK6:4 and FK6:6, respectively). Shrimp with a starting body weight of 0.55 ± 0.02 g were stocked at 22 animals per tank of 350 l capacity and fed three times daily. Results revealed that dietary krill meal and fish meal inclusion levels significantly increased growth performance (P < 0.05)and there was no significant effect on interaction between fishmeal and krill meal levels. Shrimp fed 6% krill meal diet had the highest final body weight of 11.61 g, weight gain of 11.05 g, weight gain % of 1969.38%, specific growth rate of 5.41%/d and yield of 229.42 g/tank. The weight gain % and SGR showed non significant difference between 4 and 6% krill meal containing groups. Dietary change did not affect feed conversion ratio, protein efficiency ratio and apparent protein utilization(P > 0.05). Survival was significantly increased in the groups containing 6 and 4% krill meal diets compared to 0% krill meal diet (P < 0.05). Inclusion levels of krill meal showed non-significant differences in post-fed body composition except for crude lipid and crude fibre content. Fishmeal inclusion levels showed significant (P < 0.05) variation in C14:0, C16:0, C18:0, C16:1,C18:1n-9, C18:2n-6, C22:6n-3, n-3/n-6 ratio, whereas krill meal inclusion levels showed significant variation in the all n-3 fatty acids only. Immune-related gene expression was significantly (P < 0.05) upregulated in the shrimp fed high fishmeal diets (12%) for all the analyzed genes ProPhenoloxidase (ProPO), ProPhenoloxidase activating enzyme (PPAE), Serine Protease (SP), β-1, 3-glucan-binding protein (BGBP), Superoxide dismutase (SOD), and Hemocyanin (HC). The dietary change led to a significant difference in both histology and haematology parameters (P < 0.05). The results inferred that krill meal could be used as a potential functional feed ingredient in Penaeus vannamei.The present study suggested beneficial effects of krill meal in shrimp diets. The levels of fishmeal inclusion (12 and 6%) also showed significant (P < 0.05) variations in various growth performance parameters. It is plausible that an inclusion level of 4% is the minimum for a measurable difference in growth performance.

Evaluation of composite mixture of protein sources in replacing fishmeal for Pacific white shrimp (Litopenaeus vannamei): Based on the changing pattern of growth performance, nutrient metabolism and health status

An 8 weeks feeding trial was designed to evaluate the alternative efficiency of composite mixture of protein sources in replacing fishmeal (FM) for Pacific white shrimp (Litopenaeus vannamei) with the initial weigh of 2.55 ± 0.002 g. Four isonitrogenous (44.0%) and isolipidic (6.7%) diets were formulated using different protein sources. Diet-1 (Control diet): used FM as the main protein sources; Diet-2: 50% FM was replaced by poultry by-product meal(PBM) and antarctic krill meal (AKM) (1:1); Diet-3: FM was totally substituted by PBM, AKM and corn gluten meal (CGM) (1:1:1); Diet-4, 100% FM was substituted by CGM, cottonseed meal and rice protein concentrate meal (1:1:1). Results showed that no statistical differences for growth performance were detected after shrimp fed with Diet-2 and Diet-3 compared with the shrimp fed with control diet. However, Diet-4 markedly decreased the growth performance, feed utilization and body composition. Moreover, compared with control diet, Diet-2 and Diet-3 also had no effect on modifying the concentration of total free essential amino acid (EAA), whereas Diet-4 significantly reduced the concentration of EAA in muscle. Further explored the underlying mechanism, present study shown that Diet-2 did not alter the activation of target of rapamycin (TOR) signaling and the gene expression profile of glucolipid metabolism and immune response. Compared with control diet, Diet-3 caused partial variation of the activity of TOR signaling, nutrient metabolism and immune response. However, whole plant proteins replacement diet (Diet-4) significant decreased the growth performance and damaged the health status through inhibiting TOR signaling and further depressing the nutrient turnover and immune response. According, present study demonstrated that composite mixture of PBM and AKM (1:1) might be an effective substitution to replace FM. Meanwhile, composite mixture of PBM, AKM and CGM (1:1:1) is an excellent alternative diet to totally replaced FM in shrimp feeds.

Replacement of fish meal by Antarctic krill meal in diets for European sea bass Dicentrarchus labrax: Growth performance, feed utilization and liver lipid metabolism

A sustainable growth of the aquaculture sector implies the use of sustainable novel raw materials as replacers of the traditional fishmeal (FM) and fish oil (FO) ingredients. This fact has led to the development of sustainable and functional diets as part of a management strategy to reduce the effects on fish growth performance and health derived from low FM/FO dietary contents. In this sense, Antarctic krill (Euphausia superba) is considered a potential candidate in dietary inclusions to potentiate fish growth and health status. In this study, European sea bass (Dicentrarchus labrax) were fed a practical diet with either a 15% fishmeal content (KM0; control diet) or the same diet substituted by 30% (KM5; 50 g KM/kg diet) or 50% (KM7.5; 75 g KM/kg diet) Antarctic krill meal (KM) for 12 weeks in triplicates. At the end of the feeding trial, growth performance, liver morphology, liver proximate composition, lipid classes and fatty acid profiles, as well as the expression of hepatic genes related with lipid metabolism were evaluated. Fish fed KM-based diets presented higher (p < 0.05) final weight, protein and lipid efficiency ratios, specific growth rate (SGR) and improved feed conversion ratio (FCR), irrespective of the KM dietary level. Whole body and muscle proximate composition and fatty acid profiles were similar among dietary groups. Livers of European sea bass fed the experimental diets presented similar (p > 0.05) biochemical composition and fatty acid profile. However, smaller hepatocellular area and lower grade of cytoplasm vacuolization as well as a better alignment around sinusoidal spaces were found. The analyses of liver lipid classes revealed a positive correlation between the level of dietary KM and the pigmented material such as astaxanthin and free fatty acid content, as well as a negative correlation with the cholesterol levels. The expression of hepatic genes studied demonstrated a downregulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (hmgr) and delta-6-desaturase (fads2) expression levels in fish fed KM-based diets. Besides, gene expression levels of fatty acid binding protein 7 (fabp7) and lipoprotein lipase (lpl) were significantly correlated with KM dietary levels. Altogether, these results profile KM as a potential promoter of growth and liver health in European sea bass fed low fish meal and oil diets.

Effect of Boiling Process on the Quality of Antarctic Krill Meal

Boiled processing is a common process in the production of Antarctic krill meal, and its processing conditions often affect the physical and chemical indicators of Antarctic krill meal. In order to further study the effect of boiling processing on the quality of Antarctic krill meal, this study measured the lipid peroxide value, acid value, thiobarbituric acid value (TBARS) and fatty acid of krill meal after different temperature and time treatments. The experimental results showed that compared with the non-boiling treatment group, the peroxide value, acid value and TBARS of the 40, 60, 80, and 100 ℃ were increased significantly (P 0.05). Boiling for 15, 30, 45, and 60 minutes all increased the lipid peroxidation value of Antarctic krill meal (P 0.05). And boiling time over 30 min significantly increased acid value (P<0.05). More than 30 min boiling treatments slightly increased the content of saturated fatty acids. The 60 min boiling reduced the content of polyunsaturated fatty acids from 47.186% to 43.342%. Considering comprehensively, to get better Antarctic krill meal, the boiling temperature should be controlled at 60 °C as much as possible, and the boiling time should not exceed 30 minutes.

Dietary inclusion of Antarctic krill meal during the finishing feed period improves health and fillet quality of Atlantic salmon (Salmo salar L.).

There is an urgent need to find alternative feed resources that can further substitute fishmeal in Atlantic salmon diets without compromising health and food quality, in particular during the finishing feeding period when the feed demand is highest and flesh quality effects are most significant. This study investigates efficacy of substituting a isoprotein (35 %) and isolipid (35 %) low fishmeal diet (FM, 15 %) with Antarctic krill meal (KM, 12 %) during 3 months with growing finishing 2·3 kg salmon (quadruplicate sea cages/diet). Final body weight (3·9 (se 0·04) kg) was similar in the dietary groups, but the KM group had more voluminous body shape, leaner hearts and improved fillet integrity, firmness and colour. Ectopic epithelial cells and focal Ca deposits in intestine were only detected in the FM group. Transcriptome profiling by microarray of livers showed dietary effects on several immune genes, and a panel of structural genes were up-regulated in the KM group, including cadherin and connexin. Up-regulation of genes encoding myosin heavy chain proteins was the main finding in skeletal muscle. Morphology examination by scanning electron microscopy and secondary structure by Fourier transform IR spectroscopy revealed more ordered and stable collagen architecture of the KM group. NEFA composition of skeletal muscle indicated altered metabolism of n-3, n-6 and SFA of the KM group. The results demonstrated that improved health and meat quality in Atlantic salmon fed krill meal were associated with up-regulation of immune genes, proteins defining muscle properties and genes involved in cell contacts and adhesion, altered fatty acid metabolism and fat deposition, and improved gut health and collagen structure.

Evaluation of Antarctic krill ( Euphausia superba ) meal supplementation in diets for olive flounder ( Paralichthys olivaceus )

The supplemental effect of Antarctic krill meal (KM) into a low fish meal (FM) diet was evaluated for olive flounder (Paralichthys olivaceus). A 56% FM-based diet was regarded as a high FM inclusion diet (HFM), and a low-FM diet (LFM) was prepared by replacing 50% FM from the HFM. Four other diets were prepared by supplementing 3%, 6%, 9% and 12% KM into the LFM diet gradually replacing soy protein concentrate and tankage meal (designated as KM3, KM6, KM9 and KM12 respectively). Quadruplicate groups of fish were fed one of the diets for 12 weeks. The growth performance and feed utilization efficiency were improved by the dietary KM supplementation. Digestibility of dietary protein and dry matter was increased by the KM3-9 diets. Haematocrit and haemoglobin were increased by KM supplementation. The innate immunity and antioxidant capacity assessed by Ig, antiprotease, lysozyme, GPx and SOD and the condition factor of fish were significantly increased by KM3-9 diets. Moreover, goblet cell counts, villi length and fillet yield of fish were significantly improved by all the KM-containing diets (KM3-12). A 25-day-long challenge test with the Edwardsiella tarda pathogen showed that the cumulative mortality was higher in fish fed the LFM diet than in fish fed the HFM or KM-supplemented diets. The results indicate that dietary KM supplementation in a LFM diet can increase growth performance and feed utilization efficiency, diet digestibility, intestinal development and functions, innate immunity and disease resistance of olive flounder. The recommended level of KM inclusion in a LFM diet seems to be 6.6% according to quadratic regression analysis.

Replacement of dietary fishmeal by Antarctic krill meal on growth performance, intestinal morphology, body composition and organoleptic quality of large yellow croaker Larimichthys crocea

The present study investigated the growth performance, intestinal morphology, body composition and organoleptic quality of large yellow croaker Larimichthys crocea fed a diet containing different proportions of Antarctic krill Euphausia superba meal (0, 15, 30, 45, 60 and 75%) as a substitute for fishmeal. After a 9-week feeding trial, results showed that the specific growth rate and feed efficiency ratio were not negatively affected by dietary krill meal levels. Increasing levels of dietary krill meal linearly and quadratically increased significantly FI (P < .05). Significant positive linear trends were found between the increasing levels of dietary krill meal and carotenoid concentrations, redness (a*), yellowness (b*) in skin (P < .05). And the color can be distinguished by the human eye when 15% fishmeal protein was replaced by krill meal protein due to the total color difference (ΔE) was >3. Texture and pH in muscle were not negatively affected, however, liquid holding capacity linearly decreased (P < .05). The increasing dietary krill meal resulted in a linear decrease in most of free amino acids and a linear increase in inosinic acid (P < .05). The concentrations of EPA was linearly increased with the increasing krill meal level, n-3/n-6 ratio ranged from 0.68–0.91 within the human dietary requirements. Total amino acid profile kept unchanged among all the treatments. Although the increase of dietary krill meal significantly linearly increased the content of fluorine in muscle (P < .05), the highest content was within the safe edible limit for human. The expression levels of mTOR, 4E-BP1, eIF4E, S6K1, S6 genes related to TOR signaling pathway and phosphorylation of mTOR were not significantly changed among all treatment. These results suggested that Antarctic krill meal could be a viable alternative dietary protein source for large yellow croaker. And 6.59%–32.93% of dietary krill meal can result in a better skin color and fatty acid nutritional value in muscle without negative effects on growth performance of large yellow croaker.

Effects of dietary Antarctic krill Euphausia superba meal on growth performance and muscle quality of triploid rainbow trout Oncorhynchus mykiss farmed in sea water

The present study was conducted to investigate the effects of replacement of dietary fish meal by Antarctic krill Euphausia superba meal on growth performance, body composition and organoleptic quality of triploid rainbow trout Oncorhynchus mykiss (initial body weight: 102.06 ± 0.04 g) farmed in sea water. The basal diet contained 51% of fish meal. Based on it, five isonitrogenous and isolipidic experimental diets were formulated with the protein replacement ratio of fish meal by krill meal as 0, 15%, 30%, 60% and 100%, respectively (DM0, DM15, DM30, DM60 and DM100, respectively). After an 8-week feeding trial, results showed that increasing levels of dietary krill meal linearly and quadratically increased significantly FBW, SGR and FI (P < 0.05). Significant positive linear trends were found between the increasing levels of dietary krill meal and carotenoid concentrations, redness (a*), yellowness (b*) and chroma (C*) in muscle; and significant negative trends were found in the lightness (L*) and hue (H*) responses (P < 0.05). The pH and liquid holding capacity (LHC) were not affected by dietary krill meal levels (P > 0.05). A positive quadratic trend was found between the dietary krill meal level and the springiness, and a negative linear trend in cohesiveness occurred (P < 0.05). The content of fluorine in vertebra increased linearly and quadratically significantly (P < 0.05) but the content of fluorine in muscle was not significantly affected by increasing levels of dietary krill meal (P > 0.05). The highest fluorine content in muscle was within the safe edible limit for humans. These results suggested that Antarctic krill meal could improve the growth performance and muscle pigmentation of triploid rainbow trout farmed in seawater.

Effects of Fluoride of Antarctic Krill (&amp;lt;i&amp;gt;Euphausia superba&amp;lt;/i&amp;gt;) Meal on Accumulation and Weight of Mice

Antarctic krill (<i>Euphausia superba</i>) possesses rich nutritional value, large fishing capacity and potentials for processing and utilization. However, the development and utilization of Antarctic krill is impeded by its high fluorine contents. In this study, Antarctic krill meal and sodium fluoride solution (300 mg/L) were selected as the study objects to feeding mice, and the effects of fluoride on accumulation and weight gained in small intestine, blood, liver, and kidney femur of mice were investigated. The results showed that the contents of small intestine, blood, liver and kidney in the group of the mice fed with Antarctic krill and sodium fluoride remained less than 1 mg/kg, which was slightly higher than that of the blank control group (<i>p</i>＜0.05). The fluoride contents in the femur of mice fed with Antarctic krill meal and sodium fluoride solution were ten times higher than that of the blank control group, indicating that the fluorine in Antarctic krill meal was likely different from the chemical fluorine in sodium fluoride. No signification difference on accumulation of fluoride was found in the small intestine, blood, liver and kidney of mice, but fluorine from Antarctic krill meal and sodium fluoride was obviously deposited in the femur of mice. On the other hands, the weight gained rate of mice in the sodium fluoride group was 3.22%, and that of mice in Antarctic krill meal group was 7.81%, both of that were significantly lower than that in the blank group (12.87%). The results showed that the fluorine in Antarctic krill meal inhibited the growth of mice, but its specific absorption, metabolism and transformation process in the body still needed to be further studied.

Effect of Dietary Antarctic Krill Meal on Growth Performance, Muscle Proximate Composition, and Antioxidative Capacity of Juvenile Spotted Halibut, Verasper variegatus

AbstractA 7‐wk feeding trial was conducted to evaluate the effects of dietary Antarctic krill meal (AKM) on the growth performance, proximate composition of muscles, and antioxidative capacity of juvenile spotted halibut. Six diets were formulated to contain about 50% protein and 8% lipid. A control diet (R0) without AKM and the other five diets with 8.1, 16.2, 24.3, 32.4, and 42.5% AKM supplementation (R10–50) to replace 10, 20, 30, 40, and 50% fishmeal protein were used to feed to juvenile spotted halibut. The juveniles were fed with each diet using three replicates and cultivated in the indoor culture system. Results showed that the specific growth rate, feed intake, and protein efficiency ratio in the R30 and R40 groups were significantly higher than that in other groups (P &lt; 0.05). Survival rate in the R50 group was significantly lower compared with the R0 group and the other four AKM supplementation groups. Moreover, the rising AKM levels in diets had significant effects on the chemical composition of juvenile spotted halibut, showing significantly decreased contents of crude protein, but increased lipid and ash contents (P &lt; 0.05). The total superoxide dismutase activity and catalase activity of serum and liver in AKM groups were significantly higher than those in the control group (P &lt; 0.05). In contrast, the contents of malondialdehyde in serum and liver were significantly lower compared with the control group. These findings illustrate that a moderate AKM level in diets can significantly improve the growth performance, feed utilization, and antioxidative capacity in juvenile spotted halibut, which support the finding that AKM may be used as a good protein source for halibut in the aquafeed industry.

The effect of low inclusion levels of Antarctic krill (Euphausia superba) meal on growth performance, apparent digestibility and slaughter quality of Atlantic salmon (Salmo salar)

Two trials with Atlantic salmon (Salmo salar) were conducted to evaluate the potential of krill meal to improve feed intake. In the first experiment, after transfer to sea water, salmon smolts were fed diets added 75 or 150 g kg−1 Antarctic krill meal in substitution for fish meal for 13 weeks. The apparent digestibility coefficient for crude protein and the majority of the amino acids was significantly lower in the feeds added krill meal (around 83.5%) than in the control diet (84.9%), whereas the digestibility of crude lipids, dry matter and energy was not significantly different among the three diets. Krill meal addition resulted in higher feed intake, which led to higher growth rates and final body weights. In the second experiment, large salmon were fed a diet containing 100 g kg−1 krill meal for 6 weeks before slaughter. Their feed intake and growth performance were assessed, and fillet and visceral fat contents were measured. Salmon fed the 100 g kg−1 krill meal diet tended to eat more, resulting in significantly increased growth rates, when compared to control fish. Fish fed krill meal also had a significantly lower condition factor.

Antarctic krill meal as an alternative protein source in pet foods evaluated in mink (Neovison vison). II. Growth

Antarctic krill meal as an alternative protein source in pet foods evaluated in mink (Neovison vison). II. Growth

Antarctic krill meal as an alternative protein source in pet foods evaluated in adult mink (Neovison vison). I. Digestibility of main nutrients and effect on reproduction

Antarctic krill meal as an alternative protein source in pet foods evaluated in adult mink (Neovison vison). I. Digestibility of main nutrients and effect on reproduction

Lipid classes and fatty acid compositions of Antarctic krill meal

The lipid classes of Antarctic krill meal were analyzed,and the fatty acid compositions of different lipid components were comparatively studied by gas chromatography/mass spectrometry(GC/MS) after preparation by thin layer chromatography and acid-catalyzed esterification.The main results were as follows: ①The lipid components were abundant in Antarctic krill meal,and the content of total lipids was up to 11.37%.The total lipids were primarily composed of triglycerides,phospholipids and free fatty acids,while the total cholesterol content was low.②The predominant fatty acids of total lipids were C16:0,C18:1n-9,C18:1n-7,C20:5n-3 and C22:6n-3,and the total content of C20:5n-3 and C22:6n-3 reached 30.67%,which indicated that Antarctic krill meal had the high nutritional value and great potential for development in lipids.③Significant differences were demonstrated among the fatty acid compositions of different lipid components.The saturated fatty acids(SFA) and monounsaturated fatty acids(MUFA) of cholesterol esters and triglycerides were significantly higher than those of free fatty acids and phospholipids(P0.05);whereas the polyunsaturated fatty acids(PUFA) of free fatty acids and phospholipids were 48.50% and 49.96%,respectively,and were markedly more than 13.11% in cholesterol esters and 24.36% in triglycerides(P0.05).