Red Fillets Research Articles

Fecal Microbiome Analysis Distinguishes Bacterial Taxa Biomarkers Associated with Red Fillet Color in Rainbow Trout.

The characteristic reddish-pink fillet color of rainbow trout is an important marketing trait. The gastrointestinal microbiome is vital for host health, immunity, and nutrient balance. Host genetics play a crucial role in determining the gut microbiome, and the host-microbiome interaction impacts the host's phenotypic expression. We hypothesized that fecal microbiota could be used to predict fillet color in rainbow trout. Fish were fed Astaxanthin-supplemented feed for six months, after which 16s rDNA sequencing was used to investigate the fecal microbiome composition in rainbow trout families with reddish-pink fillet coloration (red fillet group, average saturation index = 26.50 ± 2.86) compared to families with pale white fillet color (white fillet group, average saturation index = 21.21 ± 3.53). The linear discriminant analysis effect size (LEFse) tool was used to identify bacterial biomarkers associated with fillet color. The alpha diversity measure shows no difference in the red and white fillet groups. Beta diversity principal component analysis showed clustering of the samples along the white versus red fillet group. The red fillet group has enrichment (LDA score > 1.5) of taxa Leuconostoc lactis, Corynebacterium variabile, Jeotgalicoccus halotolerans, and Leucobacter chromiireducens. In contrast, the white fillet group has an enriched presence of mycoplasma, Lachnoclostridium, and Oceanobacillus indicireducens. The enriched bacterial taxa in the red fillet group have probiotic functions and can generate carotenoid pigments. Bacteria taxa enriched in the white fillet group are either commensal, parasitic, or capable of reducing indigo dye. The study identified specific bacterial biomarkers differentially abundant in fish families of divergent fillet color that could be used in genetic selection to improve feed carotenoid retention and reddish-pink fillet color. This work extends our understanding of carotenoid metabolism in rainbow trout through the interaction between gut microbiota and fillet color.

RNA-Seq analysis of the pyloric caecum, liver, and muscle reveals molecular mechanisms regulating fillet color in rainbow trout

BackgroundThe characteristic pink-reddish color in the salmonids fillet is an important, appealing quality trait for consumers and producers. The color results from diet supplementation with carotenoids, which accounts for up to 20–30% of the feed cost. Pigment retention in the muscle is a highly variable phenotype. In this study, we aimed to understand the molecular basis for the variation in fillet color when rainbow trout (Oncorhynchus mykiss) fish families were fed an Astaxanthin-supplemented diet. We used RNA-Seq to study the transcriptome profile in the pyloric caecum, liver, and muscle from fish families with pink-reddish fillet coloration (red) versus those with lighter pale coloration (white).ResultsMore DEGs were identified in the muscle (5,148) and liver (3,180) than in the pyloric caecum (272). Genes involved in lipid/carotenoid metabolism and transport, ribosomal activities, mitochondrial functions, and stress homeostasis were uniquely enriched in the muscle and liver. For instance, the two beta carotene genes (BCO1 and BCO2) were significantly under-represented in the muscle of the red fillet group favoring more carotenoid retention. Enriched genes in the pyloric caecum were involved in intestinal absorption and transport of carotenoids and lipids. In addition, the analysis revealed the modulation of several genes with immune functions in the pyloric caecum, liver, and muscle.ConclusionThe results from this study deepen our understanding of carotenoid dynamics in rainbow trout and can guide us on strategies to improve Astaxanthin retention in the rainbow trout fillet.

Effects of Aeromonas sobria on physiology and fillet quality of market‐sized Channel Catfish Ictalurus punctatus

AbstractChannel Catfish Ictalurus punctatus fillets are rejected by processing plants because of diffuse red discoloration, but the cause of the red discoloration is currently unknown. Previous studies have shown a correlation between Aeromonas sobria and the occurrence of red fillet, although causation has not been established and little is known of the effects of A. sobria on catfish. Therefore, the present study inoculated Channel Catfish with A. sobria to determine whether inoculation induced red discoloration in fillets. Visual examination of the muscle of fish inoculated with A. sobria showed diffuse red blotches around the inoculation area and muscle histology showed increased presence of leukocytes and red blood cells, edema, and necrosis. Inoculation with A. sobria also resulted in necrosis of hematopoietic tissue, interstitial hemorrhage and melanomacrophage aggregates in the posterior kidney, and inflammation in the anterior kidney and spleen. These findings demonstrate intramuscular inoculation of A. sobria can result in red fillets and impact hematopoietic and erythrocytic tissues. Further research will be necessary to assess red fillet prevention and control for both catfish farmers and processors.

Effects of acute environmental and handling exposure on physiology and fillet quality of market‐sized Channel Catfish

Catfish Ictalurus spp. are subjected to stressful conditions during harvest, which may be linked to fillet coloration and quality. Poor water quality in ponds, socks or hauling tanks, as well as handling stress, have been suggested to cause red fillets in catfish; however, chronic exposure has not resulted in red fillets. Short-term occurrences of extreme poor water quality, particularly low dissolved oxygen, high carbon dioxide and high temperature, may occur in ponds or during harvest. Therefore, market-sized Channel Catfish Ictalurus punctatus were acutely exposed (12 hr) to one of the three water quality treatments while confined during a simulated socking procedure and evaluated for stress responses by means of change in blood parameters and fillet quality. In fish subjected to the extreme treatment, hematocrit, plasma cortisol, glucose and lactate levels increased, with 22% mortality, indicating highly stressful conditions. In fish subjected to moderate and typical (control) treatments, cortisol increased but a lack of change or decrease in glucose and lactate indicated minimal anaerobic metabolism. Only one red fillet was produced by the extreme treatment and two by the typical treatment; therefore, the results suggest red fillets are not a product of poor water quality compounded by handling during harvest.

An assessment of red fillet prevalence in the catfish industry

Nonstandard Channel Ictalurus punctatus and Hybrid I. punctatus × I. furcatus Catfish fillets are rejected by catfish processors primarily due to aberrations in muscle texture or coloration (i.e., yellow, pink, red), and represent an economic loss for both the processer and farmer. Of these fillet types, red fillet is characterized by red coloration, with affected areas ranging from a solitary spot to the whole fillet. The present study investigates the prevalence of red fillet within the catfish industry and evaluates compositional differences in fillets by means of color, proximate composition, and microbial presence between red (diffuse red patch), punctured (singular red spot), and acceptable fillets. Red fillets with presence of different bacteria were also compared histologically. In order to evaluate the occurrence of red fillet, subsamples of acceptable and rejected fillets were obtained biweekly from a commercial processing plant over the course of a year, with rejected fillets sorted as red, punctured, or neither. Red fillets accounted for an average of 0.13% fillets from each pond harvest, representing an estimated annual loss of $443,000 for catfish farmers and $683,000 for catfish processors. Red and punctured fillets did not significantly differ in color (lightness and redness), pH, fat, protein, or moisture. Red and punctured fillets were darker, redder, and yellower than acceptable fillets. Acceptable fillets had more fat and less moisture than red and punctured fillets. Microbial analyses were similar for both red and punctured fillets with Aeromonas sobria being the most prevalent bacterium (62%) followed by Plesiomonas shigelloides (28%) and A. hydrophila (19%). Fewer acceptable fillets had bacteria than red or punctured fillets, with A. sobria as the most abundant bacterium (24%). The prevalence of A. sobria in red catfish fillets may warrant further investigation into the effect of bacteria on the development of red fillets in intensively-reared Channel and Hybrid Catfish.

La decoración pictórica del Municipium Urbs Victrix Osca (Huesca)

En este estudio se analizan cuatro conjuntos pictóricos hallados en la excavación urbana realizada en la calle Dormer nº 8-10. El primero presenta zócalo con imitaciones marmóreas y zona media en la que alternan paneles anchos y estrechos; un friso decorado con flores de loto estilizadas debía corresponder al remate superior de la pared. El segundo conjunto es el que ofrece un mayor interés; el zócalo presenta una serie de placas que imitan mármoles de distintas variedades y en la zona media se desarrolla un sistema de relación continua sobre fondo negro. Del tercero únicamente se conserva un zócalo moteado y, finalmente, el último conjunto muestra un fondo blanco decorado con filetes rojos que articulaban una serie de paneles; el interés radica en la presencia de un graffito con una serie de numerales. La cronología de las pinturas, a tenor de los datos arqueológicos y los derivados del estudio estilístico, puede establecerse en la segunda mitad del s. I d.C.

HOUSEWIVES, <em>HETAIRAI</em>, AND THE AMBIGUITY OF GENRE IN ATTIC VASE PAINTING

So-called genre scenes or scenes of everyday life in Attic vase painting have proven irresistible to scholars of Greek iconography, and indeed to many historians working on classical Athens. Not only were the vases objects used by “regular people,” but their imagery provides tantalizing potential glimpses into the quotidian activities and everyday concerns hinted at in surviving texts. What transpired behind the closed doors of the oikos or at the height of a symposion? Yet, as iconographers have well demonstrated over the past few decades, it would be a mistake to rely upon these images as if they were photographic documents. A more fruitful interpretive strategy is to treat a scene as if it were a text, to decipher a painter’s pictorial language while recognizing the image for the construction it is. Because of their unusual or provocative iconography, certain vases have received repeated attention. Among these is an Attic red-figured hydria by the Harrow Painter (ca 470 b.c.) in the Tampa Museum of Art (Figs. 1–3), formerly in the collection of Joseph Veach Noble and discovered at Vulci in the early nineteenth century. The scene on the body (Fig. 2) is deceptively simple, lacking inscriptions or discernible mythological narrative. At the left stands a building or portico; inside sits a woman enveloped in her mantle, wearing a sakkos and holding a large mirror whose face is turned outward toward the viewer. A small boy faces her, also enveloped in his himation and wearing a red fillet (mostly flaked away), with an alabastron hanging in the field between them. Outside the structure stands a bearded, half-draped man with a mostly lost red wreath who leans on his walking staff, left hand clutching a purse or

Red Flesh in Redfish,Sebastes marinus(L.)

Occasional fillets of redfish salmon red in colour have been found in the Newfoundland area. A portion of a minced pair of the red fillets was extracted with acetone and the absorption spectrum of the solution measured at various wavelengths from 350 to 700 mμ. Maximum absorption was obtained at 475 mμ, which is similar to that of astaxanthin in acetone. An acetone extract of normal whitish-coloured redfish fillets showed no appreciable absorption over this range of wavelengths. Instances of red coloration of the flesh are also noted in haddock, cod and saithe.