Antarctic Krill Meal Research Articles

Effect of dietary fluoride derived from Antarctic krill (Euphausia superba) meal on growth of yellowtail (Seriola quinqueradiata)

Yellowtail (Seriola quinqueradiata) is the most important cultured marine fish in Japan. Dietary fish meal for yellowtail in aquaculture was replaced with 0.0%, 15.4% and 100.0% Antarctic krill meal (KM0, KM15, and KM100) and with 0.0%, 15.4%, and 100.0% low-fluoride krill meal (LFK0, LFK15 and LFK100). The fish was fed to duplicate fish groups for 92d (KM trial) or 75d (LFK trial), and fish growth was monitored.Dietary fluoride (F−) concentrations (mgkg−1) were 110, 160, and 580 (KM0, KM15, and KM100, respectively) and 98, 120, and 190 (LFK0, LFK15, and LFK100, respectively). The growth during the experimental period, weight gain, feed intake, specific growth rate, and feed efficiency in fish fed the KM100 diet were markedly lower than the other experimental groups, which showed no marked differences in growth performance.After the experiment, dorsal muscle fluoride concentrations in each group were below the detectable limit (1mgkg−1), but vertebral bone fluoride concentrations increased with increasing proportion of KM to 655 (KM0), 870 (KM15), and 2150 (KM100) mgkg−1. With increasing LFK in the feed, vertebral bone fluoride concentrations (mgkg−1) increased slightly from 500 (LFK0) to 655 (LFK15), and 695 (LFK100). No histopathological changes were detected in the liver tissue in any experimental group.It has been reported that the fluoride bioavailability was reduced with increasing water hardness, however, the dietary fluoride derived from KM exoskeleton accumulates in vertebral bones of marine fish with growth inhibition, as has already been shown for freshwater fish. Vertebral bone fluoride concentrations in two krill-eating Antarctic marine fish in the wild were 33000mgkg−1 (Champsocephalus gunnari) and 15000mgkg−1 (Notothenia rossii), but they did not show any adverse effect of growth. Therefore, fish bone fluoride accumulation apparently depends on fish species rather than the salinity of the habitat. Consequently, krill exoskeleton must be removed during the processing of Antarctic krill if indeed these krill are to be used as fish feed. However, LFK can completely replace dietary fish meal without apparent adverse effects.

Growth performance of the white shrimp, Litopenaeus vannamei, fed on practical diets with increasing levels of the Antarctic krill meal, Euphausia superba, reared in clear- versus green-water culture tanks

Litopenaeus vannamei were stocked in 25 clear-water 500-L tanks at 100 shrimp m−2 and in 25 green-water 1000-L tanks at 60 animals m−2. Four diets were formulated to include krill meal at 10, 50 or 110 g kg−1; or krill oil at 25 g kg−1 by replacing fish meal, fish oil, soybean lecithin and cholesterol. Diets had similar levels of crude protein, total energy and essential amino acids. After 72 days, shrimp reared in clear and green water showed no differences in performance among diets. In clear water, shrimp attained 13.1 ± 0.59 g body weight, 1.00 ± 0.06 g week−1 growth, 81.4 ± 7.3% survival, 780 ± 118 g m−2 yield, 16.9 ± 1.8 g shrimp−1 apparent feed intake (AFI), and 2.18 ± 0.29 food conversion ratio (FCR). In green water, shrimp attained 14.3 ± 0.81 g body weight, 1.04 ± 0.09 g week−1 growth, 91.4 ± 5.4% survival, 569 ± 69 g m−2 yield, 20.9 ± 3.2 g shrimp−1 AFI, and 2.22 ± 0.34 FCR. Diets containing krill meal or krill oil were able to fully replace the protein and lipid value of fish meal, fish oil, soybean lecithin and cholesterol at no cost to performance.

DIGESTIVE EFFICIENCY, GROWTH AND QUALITIES OF MUSCLE AND OOCYTE IN ATLANTIC SALMON (SALMO SALAR L.) FED ON DIETS WITH KRILL MEAL AS AN ALTERNATIVE PROTEIN SOURCE

ABSTRACT Atlantic krill meal and Antarctic krill meal were tested to replace fish meal in Atlantic salmon diets. Different techniques were applied to precisely evaluate dietary quality and quality of fish growth performance. Inverse relationship between trypsin specific activity (T) and ratio of trypsin to chymotrypsin (T/C ratio) as a result of increased chymotrypsin specific activity (C) in the pyloric ceca indicated fish growth status as a reduction in growth rate. These protease values in the feces could also indicate fish digestive efficiency, but could not predict fish growth status. There were relationships among feed conversion efficiency (FCE), in vitro digestibility, and pyloric cecal T/C ratio, with inverse levels of krill meal in the diets. Krill meal seemed to increase muscle protein concentration through increasing protein retention, as capacity for protein synthesis was reduced. Dietary quality tests by in vitro digestibility were corresponded with growth studies, and indicated a possibility of inclusion of krill meal at 50–60% replacements, and larger fish were more sensitive to dietary quality than smaller ones. At 80–100% replacements, in vitro digestibility and FCE reduced, and oocyte quality changed through increased trypsin-like specific activity probably because of less or abnormal oocyte development. PRACTICAL APPLICATIONS The work illustrates differences in digestive efficiency and the quality of growth performance (protein growth efficiency and capacity for protein synthesis in muscle and oocytes) in fish feeding on diets with different levels of krill meal as fish meal replacer. The advantage of using various methods simultaneously for evaluating digestive efficiency and the quality of fish growth performance is to precisely provide reasonable information for some important biological differences between fish groups that could not be explained by using growth parameter alone, especially when the numbers of samples are not high. The methods are very practical for studying food quality, food utilization and growth quality of fish in different environmental conditions and with different behaviors in aquaculture as well as in natural ecosystem where food consumption rate cannot be measured. The in vitro digestibility method, using fish crude enzyme extracts and standardized by trypsin activity, could also compare the digestive ability between different species and provide information on food quality in fish growth trials that may not be necessary to be performed.

Apparent digestibility of selected marine and terrestrial feed ingredients for tropical spiny lobster Panulirus ornatus

This study reports the dry matter (DM), organic matter (OM), crude protein (CP), total lipid (TL) and gross energy (GE) apparent digestibilities of five marine animal and three terrestrial plant feed ingredients using sub-adult tropical spiny lobster ( Panulirus ornatus) of 600–800 g. Apparent digestibility was determined using standard substitution procedures and employing ytterbium as the digestibility marker. Test ingredients were used at a substitution rate of 500 g kg − 1 or 300 g kg − 1 for animal or plant ingredients, respectively. In each of the two digestibility experiments ( n = 5, the reference and four substituted diets were fed to lobsters fitted with a balloon fecal collection device. This enabled the collection of voided feces without contact with seawater and subsequent leaching losses. The derived DM, OM, CP, TL and E apparent digestibilities respectively were: 76, 81, 89, 64 and 83% for New Zealand mussel meal; 67, 79, 84, 77 and 81% for Peruvian fish meal; 69, 77, 89, 66 and 78% for spray-dried Antarctic krill meal; 53, 65, 85, 53 and 72% for Chilean langoustine meal; 47, 48, 59 41 and 58% for Japanese squid meal; 71, 66, 81, 41 and 72% for Australian solvent-extracted soybean meal; and 51, 57, 86, 33 and 63% for Australian dehulled lupin kernel meal (cv Wonga). The DM, OM, CP and E apparent digestibility of wheat flour were 82, 69, 74 and 72% respectively.

Effect of Antarctic krillmeal on quality of farmed Atlantic cod (Gadus morhua L.)

Farmed Atlantic cod with a mean weight of 4.8 kg were maintained for 9 weeks in sea cages and fed diets where the dietary fishmeal component was substituted with increasing proportions (0%, 22%, 63% and 100%) of meal from Antarctic krill, Euphausia superba. Wild-caught cod were included in the study as external control. At termination of feeding, all fish were slaughtered and muscle pH was immediately recorded. The fish were then stored on ice for three days and assessed for muscle pH and objective (skin and fillet colour, and fillet texture) and subjective (sensory evaluation) quality criteria. Replacement of fishmeal with krillmeal in the diets resulted in the skin colour above and below the lateral line to be more red than the control group without krillmeal substitutions, even though this difference was not significant, and with more yellow hue. Additions of krillmeal increased the muscle whiteness and yellow hue compared with the control group and wild fish. There was no difference in red hue between the groups. Muscle pH, texture or sensory attributes were unaffected by dietary inclusion level of krillmeal. Wild-caught cod deviated in several aspects from the farmed cod. It is concluded that the replacement of fishmeal with Antarctic krillmeal in the diets two months before slaughter did not move the sensory attributes more towards wild fish.

Growth, survival, and development of Atlantic cod (Gadus morhua L.) weaned onto diets containing various sources of marine protein

AbstractWe studied the effects of partial or complete substitution of fishmeal with alternative sources of marine protein (amphipod or krill meal) on growth, survival, liver index, and deformities of juvenile cod (Gadus morhua L.). The diets contained either 100% fishmeal or fishmeal that was replaced with 25%, 50%, or 100% amphipod meal or 50% or 100% Antarctic krill meal. Cod larvae were start-fed on rotifers and weaned directly to one of the six formulated feeds at a mean wet weight of 28 mg, 40 days post first-feeding. The mean weight of fish reared on different diets at the end of the experiment ranged from 0.92 to 2.52 g. The best growth was obtained by cod fed 100% fishmeal and 50% krill meal. There was a trend in the direction of slower growth with increasing levels of amphipod meal in the diets. Survival ranged from 87% to 79%, and there was a tendency for higher mortality with increasing content of amphipod meal. The liver index varied between 11.7% and 9.9%. The composition of the diets also had a significant influence on the occurrence of skeletal deformities. The highest proportion of deformities (16% of all fish) was in fish fed 100% amphipod meal, decreasing as the proportion of amphipod meal in the diets declined. A similar effect was not seen with Antarctic krill meal. The amphipod meal had a high content of ash, fluoride, cadmium, and mercury, which may have caused the deformities.