Enriched Feed Research Articles

Isotope fractionation in juvenile and large rainbow trout (Oncorhynchus mykiss): Repeatability of stable isotope measures and their relationship to growth rate

The study aimed to assess the repeatability of isotope ratios, δ13C and δ15N in four tissues (muscle, liver, adipose fin, and visceral adipose) and the relationship between growth rate and these measures in rainbow trout (Oncorhynchus mykiss). Tissue samples were from two experiments with, respectively, juvenile (n = 10; Experiment 1, one tank) and large (n = 120; Experiment 2, three tanks) rainbow trout, fed commercial diets. In Experiment 2, the estimated repeatability was high for both δ13C and δ15N in muscle and liver, making one measure suffice (r = 0.70–0.78 and r = 0.80–0.91, respectively). Using regression analysis, bioaccumulation of δ13C in muscle and δ15N in liver (over life), through fractionation (without feed enrichment or depletion strategies) was found to be, respectively, negatively and positively associated with growth rate. Even though individual feed intake was not recorded, the significant relationship between GR (that correlates with feed efficiency) and, respectively, MC and LN, suggests isotopic fractionation as potential biomarkers for individual cumulative (over-life) feed efficiency in fish.

Fish Spawning Training by Injecting Mating Method and Feed Enrichment with Turmeric Flour at SMKN 1 Sebatik Barat, Kabupaten Nunukan

Catfish (Clarias sp.) is one of the freshwater commodities that is favored because of its high economic value, rich in protein, can be cultivated in narrow land or yards and of course much in demand by the public. Efforts to develop in cultivation continue to be made, including an increase in seed production. The purpose of this activity is to provide training to partners in this case are students of the Department of Fisheries Cultivation, SMKN 1 Sebatik Barat regarding the semi-artificial spawning system (injection mating) and enrichment of feed with turmeric flour to support increased production and quality of catfish seeds. The methods used are socialization and counseling with lectures, hands-on practice related to injecting mating techniques with ovaprim hormone and making feed enriched with turmeric flour. The results of the activity showed an increase in partner knowledge regarding the benefits of turmeric and the role of hormone use in hatchery activities. In addition, partners have also been able to select gonadally mature broodstock, make feed enriched with turmeric flour and perform injection mating of catfish with hormones appropriately. The hope for follow-up is that partners can apply the techniques that have been learned for hatchery activities so that the scarcity of seeds, especially in West Sebatik, can be overcome and no longer have to bring in from outside

A feed enrichment strategy targeting the tricarboxylic acid cycle for increasing monoclonal antibody production and alleviating ammonia accumulation in Chinese hamster ovary cell culture

In this study, we demonstrated a simple strategy for increasing mAb production by enriching an existing feed with TCA cycle intermediates and precursors. TCA cycle intermediates/precursors were tested individually and as mixtures, termed as ‘Enriched Feeds’. The enriched feed mixtures were tested in two compositions comprising: (i) only TCA intermediates/precursors that individually increased mAb titre (EF_Partial) and, (ii) all TCA intermediates/precursors (EF_Complete). These mixtures were also tested for initiation at two phases: (i) from Day 3 (start of exponential phase) and, (ii) from Day 6 (start of stationary phase), and at two concentration levels (high and low). Our results showed that the EF_Partial mixtures were more efficient in increasing mAb titre as compared to the EF_Complete mixtures. The EF_Partial_D6_Low mixture gave the highest titre increase of 55 %, as compared to the control culture. Additionally, a decrease in ammonia production was observed immediately upon the supply of the enriched feeds. In the individual assessment, succinate supplementation resulted in a superior cell growth profile and also exhibited the most significant reduction in ammonia. The individually tested TCA compounds and mixtures also did not impact mAb quality. Therefore, in this study, we demonstrate that a simple approach of enriching feeds with TCA cycle intermediates/precursors effectively increases mAb production by > 50 % without affecting quality attributes.

Vegetarian vs. Carnivore Feeding Enrichment in a Pack of Captive Iberian Wolves (Canis lupus signatus): Towards Individual and Species-typical Needs?

The aim of this study was to compare two different types of feeding enrichment (vegetarian vs. carnivore) through the daily activity, space use and inter-individual distances in a captive Iberian wolf (Canis lupus signatus) pack housed at the Barcelona Zoo. Multifocal sampling methods were used for data collection and instantaneous scans were made at 15-min intervals during sessions of varying duration. The enrichment sessions were carried out once a day, three days per week –Monday, Wednesday, and Friday- repeating the delivered schedule of items every two weeks. Thus, both feeding phases included six different enrichment sessions; the vegetarian phase included chopped fruit – apples inside a burlap sack, scattered bananas, peaches, frozen pears, and oranges, and kiwis inside a frozen water block; the carnivore phase included animal products -beef raw lean meat inside a burlap sack or inside a frozen water block, horse leg, live carp, frozen rabbit skin and live grasshoppers-. There were individual differences in the response to both feeding enrichments. Only the carnivore enrichment provoked statistically significant differences in exploration, locomotion, inactivity and not visible. Only the indeterminate zone showed changes during both enrichment phases. The inter-individual distance between Iberian wolves was statistically significantly lower during both feeding enrichment phases –especially during the carnivore as compared to the vegetarian phase- than during the baseline phase. Enrichment items designed more according to the natural history of these animals seem to have a greater capacity to improve the wolf welfare. Future studies on this species are necessary to improve husbandry techniques, welfare, and conservation programs.

БӨДЕНЕЛЕРДІ ӨСІРУ КЕЗІНДЕ ЭКСТРУДТАЛҒАН КОМПОНЕНТТЕРМЕН АЗЫҚТЫ ПАЙДАЛАНУ ТИІМДІЛІГІ

The article is devoted to the study of the growth of quails when using feed enriched with vegetable additives with the inclusion of extruded components in it. Feeding enriched feed according to the developed recipe had a significant impact on the growth and weight indicators of quails. It revealed that the weight of the EG bird in all periods of growth is greater than that of the CG, average for the entire period by 30%. At the end of the research, the EG bird weighed 231.3±3.3 g, and the CG bird 181.1±6.3 g. The absolute weight gain for the entire period the CG was 135.3±6.7 g, while in birds the EG was 186.3±3.3 g. In addition, EG birds’ puberty, juvenile molting ended in time, oviposition began on the 40th day age, while in CG birds on the 55th day. Therefore, the proposed developed feed with extruded components has a positive effect on growth intensity and recommend for use in quail breeding farms.

Determining Factors Of The Spatial Distribution Of Sumatra Elephant Track Activities in Pemerihan Resort Bukit Barisan Selatan National Park

The movement of Sumatran elephants from forests to villages and agricultural lands triggers elephant-human conflicts. The increase in conflict between Sumatran elephants and humans has caused a drastic decline in the Sumatran elephant population. The decline in the Sumatran elephant population indicates the importance of the conservation efforts carried out on the results of research studies related to the traces of Sumatran elephant activities. This study aims to analyze the relationship between activity traces and the characteristics of the Sumatran elephant habitat at Pemerihan Resort. The research was carried out from July 2021 to January 2022. The direct observation carried out in the observation line is 1 km long and 250 m wide (4 transect lines) with 4 repetitions. The results showed that the spatial distribution of Sumatran elephant activity traces is related to habitat characteristics, namely land cover type (secondary forest), topographic class (flat), distance from water sources (<1000 m), and distance from settlements (1000-2000 m). Traces of activity can be interpreted as an indicator of knowing the presence of Sumatran elephants that can prevent and minimize conflict levels. Management of the habitat and population of Sumatran elephants through enrichment of feed and captive activities is needed as a form of Sumatran elephant conservation efforts.
 Keywords: activity traces, habitat, Pemerihan Resort, Sumatran elephant

Effect of Photoperiod and Glycerol Supplementation on the Biomass Productivity and Protein Production of Spirulina sp. LEB 18 Cultures

Changes in nutritional and lighting conditions to obtain compounds of interest and biomass via microalgal cultures are among the main foci of studies in algal biotechnology. Growth medium supplementation using organic compounds, such as glycerol, is a promising approach for increasing biomass productivity and the viability of microalgal cultivation and adding value to byproducts of the biodiesel industry. In this study, the influence of crude glycerol on Spirulina sp. LEB 18 was investigated via culturing using different photoperiods, and its effect on biomass composition and cell growth was evaluated. The microalgae were subjected to three photoperiods (continuous light, 24:0; 12 h light and 12 h dark, 12:12; and no illumination, 0:24) and crude glycerol supplementation (2.5 g L−1); better productivity and biomass concentrations were obtained in cultures with a 12:12 photoperiod (28.36 mg L−1 h−1 and 1.24 g L−1, respectively). Under this condition, the highest protein yield was achieved (647.3 mg L−1, 52.2% w w−1), and the obtained biomass showed favorable characteristics for applications in animal feed enrichment.

Social structure and habitat design affect the impact of a novel feeding enrichment for alligators.

Providing enrichment that expands the range of behavioral opportunities associated with food acquisition and environmental exploration is an important contributing factor to the well-being of zoo animals. These behaviors can be difficult to promote in carnivores, given their foraging strategies and the logistical, ethical, and financial challenges of providing live prey. In this study, we introduced a novel feeding enrichment to Jacksonville Zoo and Gardens' five adult American alligators (Alligator mississippiensis) in an attempt to simulate a live prey organism within the exhibit and promote natural hunting behaviors like chasing and lunging, as well as increase daily activity levels. The enrichment promoted some behavioral goals for two of the alligators, but it did not promote behavioral goals for the other three alligators. This could have been due to a variety of factors including an existing dominance hierarchy amongst the group's females and the resulting spatial distribution of individuals across a habitat with only one water feature. Our results suggest that female alligators may carve out territories and avoid overlapping space usage with other females during the warmest months of the year. Given the outcomes and limitations of this enrichment strategy, we provide recommendations for this group specifically as well as future enrichment efforts in the general captive crocodilian population.

Using Species-Specific Protocols for the Welfare Assessment of Elephants in the Skopje Zoo

Abstract Providing good animal welfare standards is very important for wild animals in captivity, especially in zoos. Therefore, the aim of this study was to perform a welfare assessment of elephants in the Skopje Zoo using species-specific protocols. Two specific protocols were used for the welfare assessment and were combined for a more unified approach. These protocols focused on the assessment of the elephant’s day-time behaviour, including Qualitative Behaviour Assessment (QBA), as well as the following sections: nutrition, physical health, environment, behaviour and management. Data was collected from the Asian and African elephants that were housed together, in the Skopje Zoo. Both species were observed for three consecutive days, during which time QBA was performed and they were observed on their daytime behaviour. Feeding (42% African, 34% Asian elephant) and anticipatory (35% African, 22% Asian elephant) behaviour were predominantly observed daytime behaviours of both elephants, as well as stereotypic behaviour (30%) of the Asian elephant. Concerning the QBA, ‘uncomfortable’ (296 Asian, 234 African elephants) and ‘relaxed’ (271 Asian, 280 African elephants) were the most dominant descriptors for both elephants. The collected data indicated that the elephants were in good physical health. Regular feeding enrichment, as well as environmental enrichment was recommended. There is room for improvement concerning the management practices of the elephants.

Proposal for an Improvement of Hard Coal Enrichment Accuracy in Systems with Secondary Beneficiation

There are various ways to improve the accuracy of hard coal enrichment. This article discusses the possibility of improving the accuracy of beneficiation by using the same enrichment machines located in the processing plant, introducing only the multiple (secondary) enrichment of raw coal feed. Secondary enrichment is a technology that allows for an improvement of the accuracy of mineral separation. The main advantage of this solution compared to that currently used is the lack of the necessity of introducing the crushing process. Secondary enrichment without crushing is a simple solution, and at the same time beneficial from the point of view of obtaining a commercial product with specific quantitative and qualitative parameters. This article shows the effect of this type of enrichment on the improvement of the shape of partition curves in an example of systems with two-product jigs. On the basis of the results of simulation studies, it was shown that the use of secondary enrichment results in obtaining a higher yield of concentrate of a given quality and thus increasing production value. The article uses the method of digital modelling of coal processing operations and technological systems, which should be treated as one of the possible methods of creating new knowledge, in particular knowledge about the behavior of concentrator group systems under different production assumptions and with different raw coal characteristics.

Techno-economic assessment of microalgae production, harvesting and drying for food, feed, cosmetics, and agriculture

The objective of this techno-economic analysis is to define the costs for an industrial microalgae production process, comparing different operation strategies (Nannochloropsis oceanica cultivation during the whole year or cultivation of two species, where Phaeodactylum tricornutum and Tisochrysis lutea alternate), production scales (1 and 10 ha), harvesting technologies (centrifugation or ultrafiltration) and drying methods (freeze-drying or spray drying). This study is based on an industrial scale process established in the south of Portugal. The strategy of cultivating N. oceanica all year round is more attractive from an economic perspective, with production costs of 53.32 €/kg DW and a productivity of 27.61 t/y for a scale of 1 ha, a 49.31% lower cost and two-fold productivity than species alternation culture strategy. These results are for biomass harvested by centrifugation (10.65% biomass cost) and freeze-drying (20.15% biomass cost). These costs could be reduced by 7.03% using a combination of ultrafiltration and spray drying, up to 17.99% if expanded to 10 ha and 10.92% if fertilisers were used instead of commercial nutrient solutions. The study shows potentially competitive costs for functional foods, food, and feed additives, specialised aquaculture products (live feed enrichment) and other high value applications (e.g., cosmetics).

Nutraceutical Enrichment of Animal Feed by Filamentous Fungi Fermentation

There is an urgent need for improvements in animal production, particularly for ruminants, such that more sustainable and efficient processes are developed for obtaining more nutritious and efficient feeds. Filamentous fungi can add value to residual plant biomass, and may also have the potential to produce metabolites and enrich plant biomasses used in animal nutrition, converting them into nutraceutical sources. Thus, in this work, filamentous fungal fermentation of ruminant feed biomasses commonly used in Brazil was performed, and the enrichment for bioactive metabolites was tested. For this, Fistulina hepatica, Ganoderma lucidum, Pleurotus pulmonarius, Panus lecomtei, and Aspergillus terreus were grown for 28 days on different substrates: starchy grains- (sorghum, oat, and corn), fibrous substrates (coast-cross, rice husk, and moringa plant) and protein-rich substrates (cottonseed cake and pigeon pea plant). Fermented substrates were evaluated for laccase activity, crude protein, β-glucan, and lovastatin content. The highest growth rate was observed for G. lucidum in oat substrate (OT-01) (0.708 ± 0.035 cm/day) and F. hepatica in oat + coast-cross + pigeon pea treatment (OT-10) (0.607 ± 0.012 cm/day). High laccase activity was observed for P. lecomtei grown in starchy grain + moringa + pigeon pea substrate, reaching an activity of 416.8 ± 20.28 U/g. A. terreus growth in ST-09 (sorghum + pigeon pea) showed higher protein (15.3 ± 0.46%), β-glucan (503.56 ± 8.6 mg/g) and lovastatin (1.10 ± 0.17 mg/g) content compared to untreated substrates. These results demonstrate that filamentous fungi are an alternative for nutraceutical enrichment of ruminant feed biomasses. To the best of our knowledge, this is the first report in which P. lecomtei and F. hepatica are evaluated for their ability to be cultivated in ruminant feed substrates from Brazil.

Distribution of vitamin B12 in bivalve tissues: Investigations of larval and adult lifestages

Shellfish, in particular bivalves, are an often-overlooked source of vitamin B12 (B12) in the human diet although they have significantly higher tissue levels of B12 than other animal meat or fish sources, including all vertebrates. However, the origins and key metabolic processes involving B12 in bivalves remain largely unknown. In this study, we examined the distribution of B12 in tissues of several adult Australian bivalve species and assessed hypotheses concerning their B12 utilisation and principal uptake, specifically whether it is derived from diet or gut microbiome. Pacific oysters, Crassostrea gigas, and Goolwa cockles, Plebidonax deltoides (‘pipis’), are both high in B12 (28.0–49.4 μg/100 g total per individual). Vitamin B12 tissue distribution, particularly in oysters, varied significantly, with higher amounts in the adductor muscle (44.0–96.7 μg/100 g), and other tissues, such as gonads, were relatively low (12.7–35.9 μg/100 g). In comparison, concentrations of B12 in the adductor muscle and roe of Southern Australian scallops, Pecten fumatus, were appreciably lower (3.4–10.8 μg/100 g). We also demonstrated that microalgal feed commonly grown in aquaculture can be supplemented directly with B12, resulting in an enriched feed. However, the B12-enriched diet did not transfer to a significant increase in oyster larval B12 concentrations, contradicting our theory that vitamin uptake through feed was a primary B12 source. Vitamin B12 concentrations across oyster larval life stages showed a significant decrease post metamorphosis, which indicates a higher utilisation of B12 during this life event. Our findings also provide insight into B12 uptake and tissue distribution in bivalve species, which can aid the aquaculture industry in promotion of bivalves as a valuable source of dietary B12 for human consumers, while also suggesting ways to optimise vitamin supplementation in bivalve hatchery production.

Enrichment of commercial feed with new formula products on the growth, yield, and mortality of the giant gourami Osphronemus goramy

Background and objective: The giant gurami (Osphronemus goramy) is considered the most desirable freshwater species in Indonesia, mainly for food security. This study evaluated the effectiveness of newly formulated products containing water, coconut, palm sap sugar, and fungus used for enriched commercial feed and their impact on gurami sago’s (local strain) growth performance, yield, and mortality. Methods: A total of 100 g of palm sugar are cooked with 1,000 ml of freshwater for fifteen minutes at a temperature of 60 °C. Furthermore was added 2,000 ml of mature coconut water. For every 1,000 ml of a mixture of mature coconut water and palm sap sugar solution was added 2 g of Aspergillus niger (called product P1), 2 g of Rhizopus oligosporus (product P2), and 2 g of Saccharomyces cerevisiae (product P3). Commercial fish feed pellets enriched with P1, P2, and P3 were designated as P1, P2, and P3 diets. At the same time, the commercial feed added with freshwater is called P4 feed (placebo). The dosage of each product is 300 ml/kg of feed. Juvenile sago gourami (initial weight 50±2.5 g and total length 13.2±0.4 cm) were stocked in triplicate (0.5x0.5x0.5 m) in a freshwater concrete pond with a stocking density of 30 individuals. /net, an initial feeding rate of 3% per day for 90 days of the experiment. Results: The weight gain ranged from 172.43 to 215.6%, the specific growth rate increased from 0.60 and 0.75%/day. The coefficient of thermal growth increased from 27.26 to 32.83. At the same time, yield ranging from 14.88 to 21.03 g/L and mortality for 90 days of the experiment decreased from 22.22% to 6.66%. The coefficient of variation in weight was between 0.68% and 1.30%. Conclusion: Giant gourami juvenile survived and grew well in diet P2, moderate growth in diet P3, and diet P1; the lowest growth was recorded in diet P4.

Laboratory breeding of two Phortica species (Diptera: Drosophilidae), vectors of the zoonotic eyeworm Thelazia callipaeda

BackgroundSome species of drosophilid flies belonging to the genus Phortica feed on ocular secretions of mammals, acting as biological vectors of the zoonotic eyeworm Thelazia callipaeda. This study describes an effective breeding protocol of Phortica variegata and Phortica oldenbergi in insectary conditions.MethodsAlive gravid flies of P. oldenbergi, P. variegata and Phortica semivirgo were field collected in wooded areas of Lazio region (Italy) and allowed to oviposit singularly to obtain isofamilies. Flies were maintained in ovipots (200 ml) with a plaster-covered bottom to maintain high humidity level inside. Adult feeding was guaranteed by fresh apples and a liquid dietary supplement containing sodium chloride and mucin proteins, while larval development was obtained by Drosophila-like agar feeding medium. The breeding performances of two media were compared: a standard one based on cornmeal flour and an enriched medium based on chestnut flour. All conditions were kept in a climatic chamber with a photoperiod of 14:10 h light:dark, 26 ± 2 °C and 80 ± 10% RH.ResultsFrom a total of 130 field-collected Phortica spp., three generations (i.e. F1 = 783, F2 = 109, F3 = 6) were obtained. Phortica oldenbergi was the species with highest breeding performance, being the only species reaching F3. Chestnut-based feeding medium allowed higher adult production and survival probability in both P. oldenbergi and P. variegata. Adult production/female was promising in both species (P. oldenbergi: 13.5 F1/f; P. variegata: 4.5 F1/f).ConclusionsThis standardized breeding protocol, based on controlled climatic parameters and fly densities, together with the introduction of an enriched chestnut-based feeding medium, allowed to investigate aspects of life history traits of Phortica spp. involved in the transmission of T. callipaeda. Obtaining F3 generation of these species for the first time paved the road for the establishment of stable colonies, an essential requirement for future studies on these vectors in controlled conditions.Graphical abstract

Growth Performance of Tilapia Fed with Feed Containing Moringa Leaf Meal and Shrimp Meal

The research objective of this study was to determine the impact of feed enrichment using Moringa leaf meal and shrimp meal on the growth performance of Tilapia. The initial weight of experimental fish was 6.10 ± 0.55 g/ head. The treatments given were Treatment A (feed without Moringa leaf meal and shrimp meal), Treatment B (commercial feed + 20% shrimp flour), Treatment C (commercial feed + 10% Moringa leaf meal + 20% shrimp meal), and Treatment D (commercial feed + 20% Moringa leaf meal + 20% shrimp meal). In total, there were 4 treatments with 3 replications each. Fish rearing lasted for 40 days. The results showed that the treatments had no effect on amount of feed consumption, protein efficiency ratio, specific growth rate, feed efficiency, survival rate, coefficient of variation and hepatosomatic index (p>0,05), but had an effect on the amount of protein consumption and body protein (p<0, 05). In conclusion, the enrichment of feed containing Moringa leaf meal and shrimp meal had no effect on the growth performance of Tilapia.

Addition of microalgae Nannochloropsis sp. and Isochrysis sp. in the feed of Nile tilapia larvae

Microalgae added to feed can increase the quality, production, and welfare of fish, although they contain antinutritive factors and allelopathic compounds that can be harmful. The aim of this work was to compare the effect of five feeds: Basic feed and enriched with two levels of Nannochloropsis sp. and Isochrysis sp. lyophilized (15 and 30 kg-1 of feed) in larval rearing of Nile tilapia. The larvae fed with Isochrysis sp. (15 and 30 g kg-1) had some yield parameters slightly lower than those of the larvae fed with the basal feed. For larvae fed with Nannochloropsis sp., all yield parameters were similar to those of the control group, except for the weight and stress resistance of larvae fed with the 15 g kg-1 enriched feed, which were lower than those of the control group. Since the main objective of juvenile fish producers is survival rate, which was high and stable in larvae fed with Nannochloropsis sp. (30 g kg-1), it is recommended that this feed should be used for rearing Nile tilapia larvae. The inclusion of Isochrysis sp. in the feed should be better evaluated.

Bioconversion of chitin waste through Stenotrophomonas maltophilia for production of chitin derivatives as a Seabass enrichment diet

Marine wastes pose a great threat to the ecosystem leading to severe environmental hazards and health issues particularly the shellfish wastes. The shellfish waste which contains half of the amount of chitin can be efficiently transformed into useful products. Various approaches for the hydrolysis of chitin like physical, chemical, and enzymatic processes are there. Still, the use of enzyme chitinase is well documented as an effective and eco-friendly method. The present study summarizes the isolation of chitinase enzyme producing bacteria from different shrimp waste disposal sites in Parangipettai (India), and the possible use of an enzyme hydrolyzate as an immunostimulant to Asian Seabass (Lates calcarifer). The potential chitinase-producing bacteria were identified by 16S rRNA gene sequencing as Stenotrophomonas maltophilia. After purification, the chitinase specific activity was 5.01 (U/ml) and the protein content was 72 mg and the recovery rate was 48.06%. The optimum pH and temperature for the chitinolytic activity were 6.5 and at 35–50 °C, respectively. The animal experiment trial was done with our feed supplements which included 0.0 (control), 0.5%, 1% and 2% of chitin degraded product. All the supplementary feed had an optimal 42% (w/w) of crude protein. The feed protein level was 41–43% on average and gross energy was 13–17 kcal/g and the feed was observed to exhibit a significantly higher (p < 0.05) survival rate, condition factor, specific growth rates, and body weight gain was also found to be promising compared to other fishes fed with control diet only. The red blood cells (RBC) and white blood cell (WBC) counts were found to increase significantly after being challenged with infection in animals fed with chitin derivatives from 1st week to 3rd week when compared to the control. The hematocrit (Hct) values were low on the 2nd and 3rd week in infected fish fed with chitin derivatives. This low level was due to infection lyses of the red blood cells and increased nitro blue tetrazolium reduction. The control diet-fed fish showed 70% mortality but the chitin derivative supplemented fishes showed only 20% mortality post-infection. The results of the study encompass that the use of chitin-derivate enriched feed further is taken into large-scale approaches thereby benefitting the aquaculture sector.

Iron overload and impaired iron handling contribute to the dystrophic pathology in models of Duchenne muscular dystrophy.

BackgroundOxidative stress is implicated in the pathophysiology of Duchenne muscular dystrophy (DMD, caused by mutations in the dystrophin gene), which is the most common and severe of the muscular dystrophies. To our knowledge, the distribution of iron, an important modulator of oxidative stress, has not been assessed in DMD. We tested the hypotheses that iron accumulation occurs in mouse models of DMD and that modulation of iron through the diet or chelation could modify disease severity.MethodsWe assessed iron distribution and total elemental iron using LA‐ICP‐MS on skeletal muscle cross‐sections of 8‐week‐old Bl10 control mice and dystrophic mdx mice (with moderate dystrophy) and dystrophin/utrophin‐null mice (dko, with severe dystrophy). In addition, mdx mice (4 weeks) were treated with either an iron chelator (deferiprone 150 mg/kg/day) or iron‐enriched feed (containing 1% added iron as carbonyl iron). Immunoblotting was used to determine the abundance of iron‐ and mitochondria‐related proteins. (Immuno)histochemical and mRNA assessments of fibrosis and inflammation were also performed.ResultsWe observed a significant increase in total elemental iron in hindlimb muscles of dko mice (+50%, P < 0.05) and in the diaphragm of mdx mice (+80%, P < 0.05), with both tissues exhibiting severe pathology. Iron dyshomeostasis was further evidenced by an increase in the storage protein ferritin (dko: +39%, P < 0.05) and ferroportin compared with Bl10 control mice (mdx: +152% and dko: +175%, P < 0.05). Despite having features of iron overload, dystrophic muscles had lower protein expression of ALAS‐1, the rate‐limiting enzyme for haem synthesis (dko −44%, P < 0.05), and the haem‐containing protein myoglobin (dko −54%, P < 0.05). Deferiprone treatment tended to decrease muscle iron levels in mdx mice (−30%, P < 0.1), which was associated with lower oxidative stress and fibrosis, but suppressed haem‐containing proteins and mitochondrial content. Increasing iron via dietary intervention elevated total muscle iron (+25%, P < 0.05) but did not aggravate the pathology.ConclusionsMuscles from dystrophic mice have increased iron levels and dysregulated iron‐related proteins that are associated with dystrophic pathology. Muscle iron levels were manipulated by iron chelation and iron enriched feed. Iron chelation reduced fibrosis and reactive oxygen species (ROS) but also suppressed haem‐containing proteins and mitochondrial activity. Conversely, iron supplementation increased ferritin and haem‐containing proteins but did not alter ROS, fibrosis, or mitochondrial activity. Further studies are required to investigate the contribution of impaired ferritin breakdown in the dysregulation of iron homeostasis in DMD.

Responses of largemouth bass ( Micropterus salmoides , Lacépède, 1802) to fishmeal‐, and fish oil‐free diets

Largemouth bass (LMB; ~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.