Muscle Pigment Research Articles

Dynamic Transcriptome Profile Analysis of Mechanisms Related to Melanin Deposition in Chicken Muscle Development.

The pectoral muscle is an important component of skeletal muscle. The blackness of pectoral muscles can directly affect the economic value of black-boned chickens. Although the genes associated with melanogenesis in mammals and birds have been thoroughly investigated, only little is known about the key genes involved in muscle hyperpigmentation during embryonic development. Here, we analyzed melanin deposition patterns in the pectoral muscle of Yugan black-boned chickens and compared differentially expressed genes (DEGs) between the muscles of Wenchang (non-black-boned chickens) and Yugan black-boned chickens on embryonic days 9, 13, 17, and 21. Melanin pigments were found to gradually accumulate in the muscle fibers over time. Using RNA-seq, there were 40, 97, 169, and 94 genes were identified as DEGs, respectively, between Yugan black-boned chicken muscles and Wenchang chickens at embryonic day 9, 13, 17, and 21 stages (fold change ≥2.0, false discovery rate (FDR) < 0.05). Thirteen DEGs, such as MSTRG.720, EDNRB2, TYRP1, and DCT, were commonly identified among the time points observed. These DEGs were mainly involved in pigmentation, melanin biosynthetic and metabolic processes, and secondary metabolite biosynthetic processes. Pathway analysis of the DEGs revealed that they were mainly associated with melanogenesis and tyrosine metabolism. Moreover, weighted gene co-expression network analysis (WGCNA) was used to detect core modules and central genes related to melanogenesis in the muscles of black-boned chickens. A total of 24 modules were identified. Correlation analysis indicated that one of them (the orange module) was positively correlated with muscle pigmentation traits (r > 0.8 and p < 0.001). Correlations between gene expression and L* values of the breast muscle were investigated in Yugan and Taihe black-boned chickens after hatching. The results confirmed that EDNRB2, GPNMB, TRPM1, TYR, and DCT expression levels were significantly associated with L* values (p < 0.01) in black-boned chickens (p < 0.05). Our results suggest that EDNRB2, GPNMB, TRPM1, TYR, and DCT are the essential genes regulating melanin deposition in the breast muscle of black-boned chickens. MSTRG.720 is a potential candidate gene involved in melanin deposition in the breast muscles of Yugan black-boned chickens.

Combined effects of high hydrostatic pressure and chemical pre‐treatment on physico‐chemical properties of beef, using FTIR and diffuse reflectance spectroscopy

AbstractHigh pressure processing (HPP) was combined with a previous short chemical treatment to stabilize the color of beef tissue. Beef samples were treated with a solution containing ascorbic acid, sodium chloride, and a very low concentration of sodium nitrite. The effects of pressure levels (0.1–600 MPa) and preservative solution on: (i) color properties based on diffuse reflectance spectroscopy (DRS), which determines the relative concentrations of muscle pigments, (ii) protein denaturation and changes in the secondary structures by DSC and FTIR‐ATR, were determined.At high pressures, the disappearance of DSC peaks due to protein denaturation, a decrease in the proportion of α‐helix and an increase in the percentage of disordered structures, were evidenced. DRS spectra and Kublelka‐Munk theory equations demonstrated that nitrosilmyoglobin was a more stable chromophore, decreasing discoloration of the tissue. These techniques contribute to the knowledge of the physico‐chemical properties of the tissue submitted to combined preservation processes.Practical ApplicationsThere is an increasing demand from consumers for high‐quality beef products, with significant emphasis placed on color and safety attributes. Extending the shelf life by applying high hydrostatic pressure treatment (HHP) improves food safety and will produce a positive impact on both the industry and consumers. HHP is a non‐thermal preservation technology with generally minimal effects on sensory qualities and nutritional content; however, the direct application of this technology on beef leads to the production of a product with an unacceptable pale coloration. Therefore, it must be remarked that a pre‐treatment stage by immersing the pieces in a preservative solution is essential to improve the color of beef products treated by HHP. In this regard, from a technological point of view, it is very important to know the combined effects of both stages (short chemical treatment and high‐pressure) on the quality of beef products.

Effects of synthetic astaxanthin and Haematococcus pluvialis on growth, antioxidant capacity, immune response, and hepato-morphology of Oncorhynchus mykiss under cage culture with flowing freshwater

A feeding experiment was carried out to compare the effects of dietary synthetic astaxanthin and Haematococcus pluvialis on growth, antioxidant capacity, immune response and hepato-morphology of Oncorhynchus mykiss under cage culture with flowing freshwater. Three isonitrogenous and isolipidic diets were formulated with or without synthetic astaxanthin and H. pluvialis and were administered to O. mykiss for 56 days. The results showed that growth performance and muscle lipid of O. mykiss were significantly improved by diet supplemented with synthetic astaxanthin or H. pluvialis. Feed coefficient ratio of O. mykiss fed the diets supplemented with synthetic astaxanthin or H. pluvialis was lower than that of fish fed the control diet. Besides, dietary synthetic astaxanthin or H. pluvialis supplementation significantly improved dorsal muscle pigmentation of O. mykiss. The beneficial effects on growth performance and pigmentation were more evident in synthetic astaxanthin than that in H. pluvialis. Synthetic astaxanthin or H. pluvialis supplementation activated Nrf2-ARE pathway, enhanced superoxide dismutase activity and decreased MDA content in the liver. Furthermore, synthetic astaxanthin or H. pluvialis improved the non-specific immunity by activating lysozyme and complement system, exerted anti-inflammatory activity by inhibiting the expression of pro-inflammatory cytokines (interleukin 1β, interleukin 8 and tumor necrosis factor-α) and improved the liver morphology. Based on these findings, dietary synthetic astaxanthin and H. pluvialis supplementation have a beneficial effect on the growth performance, antioxidant capacity, innate immune response and liver health of O. mykiss.

Long-term effect of a short pulse of dietary supplementation with algae on the quality of turbot (Scophthalmus maximus) frozen fillets

This study raises the question of the potential long-term effects of a feeding pulse with diets containing algal biomass on the quality of frozen turbot (Scophthalmus maximus) fillets. A feeding trial was carried out with this aim, in which juvenile turbot were fed during 60 d with six different experimental diets, two of which were enriched with the macroalgaeUlva rigida(U diets), the other two with a microalgae blend (M diets), plus a non-supplemented control diet (CT), and finally, a commercial aquafeed (COM). Two inclusion levels were considered in algae-enriched diets (50 and 100 g kg-1) so that they were designed as U5 and U10 forU. rigida, and M5 and M10 for microalgae-enriched diets. The duration of the feeding pulse with the functional diets was 60 days, and then, all specimens were fed with a COM diet for a further 150-d period until reaching a body size close to the commercial standard (approximately 750 g). Subsequently, fish were sacrificed; fillets were removed from the pigmented flank and kept at -20 °C for 5 months. Then, fillets were thawed and the muscle proximal composition and fatty acid profile were analyzed, and fillet quality parameters were assessed during a 10-d co\ld storage period at 4°C. The possible deferred effects of algae-enriched diets on fillet quality were compared with a control diet without algae (CT) and with a commercial diet (COM). Roughly, the results obtained indicated that a 60-d administration pulse of algae-enriched diets induced some long-term changes in both the nutritional and organoleptic quality of turbot fillets. In this regard, the algae-enriched aquafeeds improved the muscle antioxidant response throughout the cold storage period, prolonging the shelf life of thawed turbot fillets. In addition, in terms of consumers’ acceptability, this feeding pulse on pre-growing stage of the productive cycle was able to modify the skin and muscle pigmentation of fish of commercial size. Namely, the U10 diet increased the protein content, improved muscle texture, reduced fillet total lipid content, and favored muscle selective retention of n-3 polyunsaturated fatty acids. On the other hand, the strategy based on the early administration of a diet rich in fishmeal (CT) for 60 d, followed by feeding with commercial feed, also affected positively the quality of fillets, with values comparable to U10 specimens. Thus, the results obtained indicate that a two-month feeding pulse with algae-supplemented diets during pre-growing phase may represent a promising strategy to improve the nutritional and organoleptic quality of frozen turbot fillet, as well as to extend their shelf life during the post-thawing cold storage.

Weighted Single-Step GWAS Identifies Genes Influencing Fillet Color in Rainbow Trout.

The visual appearance of the fish fillet is a significant determinant of consumers’ purchase decisions. Depending on the rainbow trout diet, a uniform bright white or reddish/pink fillet color is desirable. Factors affecting fillet color are complex, ranging from the ability of live fish to accumulate carotenoids in the muscle to preharvest environmental conditions, early postmortem muscle metabolism, and storage conditions. Identifying genetic markers of fillet color is a desirable goal but a challenging task for the aquaculture industry. This study used weighted, single-step GWAS to explore the genetic basis of fillet color variation in rainbow trout. We identified several SNP windows explaining up to 3.5%, 2.5%, and 1.6% of the additive genetic variance for fillet redness, yellowness, and whiteness, respectively. SNPs are located within genes implicated in carotenoid metabolism (β,β-carotene 15,15′-dioxygenase, retinol dehydrogenase) and myoglobin homeostasis (ATP synthase subunit β, mitochondrial (ATP5F1B)). These genes are involved in processes that influence muscle pigmentation and postmortem flesh coloration. Other identified genes are involved in the maintenance of muscle structural integrity (kelch protein 41b (klh41b), collagen α-1(XXVIII) chain (COL28A1), and cathepsin K (CTSK)) and protection against lipid oxidation (peroxiredoxin, superoxide dismutase 2 (SOD2), sestrin-1, Ubiquitin carboxyl-terminal hydrolase-10 (USP10)). A-to-G single-nucleotide polymorphism in β,β-carotene 15,15′-dioxygenase, and USP10 result in isoleucine-to-valine and proline-to-leucine non-synonymous amino acid substitutions, respectively. Our observation confirms that fillet color is a complex trait regulated by many genes involved in carotenoid metabolism, myoglobin homeostasis, protection against lipid oxidation, and maintenance of muscle structural integrity. The significant SNPs identified in this study could be prioritized via genomic selection in breeding programs to improve fillet color in rainbow trout.

Influence of an increased content of pea and yellow lupin protein in the diet of pigs on meat quality

BackgroundThe aim of the study was to test the effect of replacing soya beans with pea and yellow lupin seeds in the diet of pigs on meat quality. The meat for the tests was obtained from 60 fattening crossbred pigs F1 (Polish Large White × Polish Landrace) × F1 (Pietrain × Duroc). The animals belonged to three feeding groups depending on the feed used with the total share of soybeans and its reduction. Water holding capacity, colour, and tenderness were measured and visual and tactile evaluation (colour, marbling and firmness) was performed for meat samples collected from the longissimus lumborum muscle. The chemical composition of the meat and the content of minerals were determined. The content of amino acids, fatty acids and cholesterol was determined.ResultsThere was no significant differences among the assessed physicochemical characteristics of the meat. The obtained meat was of good quality, regardless of the proportion of proteins from legumes in the diet of pigs. The results of the subjective evaluation of meat, its colour, and the content of muscle pigments were uniform in all food groups. Similarly, a uniform, high protein content was found in all tested groups (C—24.98%; E1—24.82%; E2—25.09%) and the content of macro- and micronutrients in the tested meat was equivalent. The profile of fatty acids was not significantly affected by dietary treatment. Palmitoleic acid content was significantly higher (P < 0.05) in the E2 group compared to the E1 group (3.279% compared to 2.844%). The content of amino acids in meat samples was influenced by dietary treatment. Almost all the monitored essential amino acids (threonine, valine, leucine, phenylalanine and lysine) and some of nonessential amino acids’ proportion was increased in the experimental groups (E1, E2).ConclusionReplacing soya bean protein in the pigs’ diet with legume protein (peas and yellow lupin) did not adversely affect meat quality. This applies to both the physicochemical characteristics, the basic composition and the fatty acid profile. The meat of fattening pigs fed with the highest proportion of pea and lupin in the ration was characterized by more favourable proportion of essential amino acids.

Muscle pigmentation of Nile tilapia (&lt;em&gt;Oreochromis niloticus&lt;/em&gt;) fed on crude palm oil incorporated fish feed

The effects of diets containing crude palm oil on muscle pigmentation and deposition of carotenoids in tilapia (Oreochromis niloticus) was studied. A total of 135 advanced fingerlings with an average body weight and standard length of 9.11±4.78 g and 8.1±0.8 cm, respectively were stocked in tanks for 8 weeks and fed with formulated diets containing crude palm oil (CPO) as the oil component. Weight, standard length, and carotenoid levels in fish were measured biweekly. Muscles of fish fed with the control diet and CPO incorporated diets had carotenoid levels of 0.14±0.03 µg/g and 0.28±0.01 µg/g, respectively. Skin of the fish had carotenoid levels of 3.24±0.02 µg/g in the control and 6.06±0.03 µg/g in the treatment. According to the results 3% CPO incorporated diet had a significant effect on enhancing flesh colour in tilapia. The sensory evaluation indicated that the flesh of CPO fed tilapia fillets were more attractive than the fillets of fish fed control diet. CPO oil is recommended as a natural food colourant for improving flesh quality of Nile tilapia fillets.

The relationship between acidification (pH) and meat quality traits of polish white breed pigs

The paper presents the results of a study on the relationship between acidification (pH) and standard quality characteristics of the meat of Polish Large White × Polish Landrace pig crossbreds. The meat for the study was obtained from 184 F1 Polish Large White × Polish Landrace fatteners from a herd free of the stress-sensitivity gene. The obtained results were analysed in groups formed according to the meat’s measured pH45 values (≤ 6.3; 6.3–6.7; > 6.7) and pHu values (≤ 5.3; 5.3–5.6; > 5.6). Increasing measured pH45 values were paralleled by greater water-holding capacity and plasticity, lower drip loss, darker colour L* as assessed visually and with equipment, and greater content of muscle pigments (P < 0.01) of the evaluated meat. Higher pHu values had a more pronounced impact on WHC, free drip loss, tenderness, water content, and colour parameters: a*, b*, chroma C* (P < 0.01), and hue angle ho (P < 0.05). The obtained simple correlations between pH45 and pHu acidity and meat-quality characteristics indicate that the measured pH45 value was correlated more closely than ultimate acidification (P < 0.01) with visually assessed colour intensity, tactilely assessed meat hardness, colour lightness L* (P < 0.01), hue angle ho (P < 0.05), and muscle pigment content. On the other hand, pHu was more strongly correlated with water-holding capacity, drip loss, meat tenderness as well as water and protein content (P < 0.01).

Effects of Dietary Inclusion of Canthaxanthin- and α-Tocopherol-Loaded Liposomes on Growth and Muscle Pigmentation of Rainbow Trout (Oncorhynchus mykiss)

Dietary inclusion of canthaxanthin, a common carotenoid pigment, has been long practiced in aquaculture to give the favorable flesh color in farmed salmonids. However, carotenoids are associated with limited solubility and poor physicochemical stability, and their dose in fish feed is widely regulated. In this study, we included canthaxanthin- and α-tocopherol-loaded liposomes into fish diets and evaluated the effects of supplemented fish feed on fish growth, color, nutrition, and canthaxanthin deposition in fillets of cultured rainbow trout (Oncorhynchus mykiss). The liposomes were fabricated using lecithin as phospholipids with the initial concentrations (IC = mcanthaxanthin/mlipids, % wt/wt) of canthaxanthin at 0.1%, 0.5%, and 1.0%. Particle size characterization showed that liposome mean sizes were 109.70 ± 6.36, 105.10 ± 8.41, and 109.20 ± 5.66 nm (mean ± SD; n = 3), respectively, corresponding with liposomes synthesized at canthaxanthin IC = 0.1%, IC = 0.5%, and IC = 1%. The polydispersity index (PDI) of all samples remained lower than 0.2. There were no significant differences in the mean size and PDI between blank lecithin liposome and canthaxanthin- and α-tocopherol-loaded liposomes. The encapsulation efficiency of canthaxanthin- and α-tocopherol-loaded liposomes decreased when increasing the concentration of canthaxanthin in lecithin liposomes, with EE% values of IC = 0.1%, IC = 0.5%, and IC = 1% being 85.3 ± 2.1, 72.9 ± 1.8, and 55.3 ± 2.6, respectively. For fish growth, at the end of the experiment, final weight was significantly higher in fish fed with diet supplemented with 1 g/kg canthaxanthin- and α-tocopherol-loaded liposomes (IC = 0.5%) in comparison to other experimental control groups. The difference in color of the salmon muscle was most apparent after two months of feeding. However, after three months, there was no noticeable change in the color score of the fish muscle, indicating saturation of color of the fish muscle. The above results suggest the potential of canthaxanthin- and a-tocopherol-loaded liposomes as the red pigment in fish aquaculture.

Evaluation of Arthrospira sp. enzyme hydrolysate as dietary additive in gilthead seabream (Sparus aurata) juveniles

The aim of this work was to evaluate the effects of the dietary inclusion of Arthrospira sp. enzyme hydrolysate on gilthead seabream (Sparus aurata) juveniles in a 128-day feeding trial. Algal hydrolysate was tested at low inclusion level, namely, 2 and 4%, against a control diet without Arthrospira sp. supplementation. At the end of the feeding trial, fish body weight was recorded for growth evaluation. No significant differences were found among the experimental groups regarding growth performance or nutrient utilization, despite the fact that those animals fed with diets enriched with Arthrospira displayed higher trypsin, chymotrypsin, and leucine aminopeptidase enzyme activities, compared to fish fed with control diet. The ultrastructural study of the intestinal mucosa also revealed increased microvilli length and absorptive capacity in fish fed with Arthrospira sp. diets, especially at 4% inclusion level. Arthrospira supplementation was also responsible for lower lipid oxidation in muscle tissue, as well as for remarkable colour differences in skin, compared to control animals. These results suggest, overall, that low dietary supplementation with this microalgal hydrolysate might improve not only the intestinal ultrastructure and functionality but also muscle pigmentation and antioxidant capacity of juvenile gilthead seabream.

Identification of key microRNAs affecting melanogenesis of breast muscle in Muchuan black-boned chickens by RNA sequencing

ABSTRACT 1. Melanin content is considered an important indicator of meat quality in black-boned chickens, which have a high market value. To understand the complex physiological processes underlying muscle melanogenesis in this chicken, differentially expressed miRNAs (DEMs) were detected between black muscle (BM) and white muscle (WM) of chickens using high-throughput sequencing technology. Six small RNA libraries were constructed, and more than 16.75 million clean reads were obtained for each library. 2. A total of 582 known miRNAs and 65 novel miRNAs were identified from the six chicken sequence libraries. A total of 19 DEMs were identified between the two groups, of which nine were upregulated and 10 were downregulated. Furthermore, the DEMs were predicted to target 572 genes. 3. Certain DEMs (such as miR-204, miR-133b, and miR-12 229-3p) and their target genes may play an important role in muscle melanogenesis of chickens. These findings provide a foundation for clarifying the miRNA regulatory mechanisms involved in muscle pigmentation in avian species.

Tadpoles of Three Species of the Rhinella granulosa Group with a Reinterpretation of Larval Characters

The Rhinella granulosa group currently comprises 14 species of Neotropical toads, and its monophyly is strongly supported by several synapomorphies, including a distinctive set of larval characters. Recently, the identities of specimens used in the description of the tadpoles of R. major and R. mirandaribeiroi were questioned. In this work, we revise the larval external morphology of these species based on properly identified tadpoles and examine for the first time the tadpoles of R. bernardoi. Tadpoles of R. major have the labial tooth row formula 2/2 and a striped tail pattern, which were recovered as synapomorphies of the group. In contrast, tadpoles of R. mirandaribeiroi show a third posterior labial ridge arranged on a medial flap, a condition suggested as a synapomorphy of a derived subclade of the R. granulosa group. Lastly, tadpoles of R. bernardoi differ from the remaining tadpoles within the group by lacking the typical striped tail muscle pigmentation.

Effect of Black Mulberry (Morus nigra) Powder on Growth Performance, Biochemical Parameters, Blood Carotenoid Concentration, and Fillet Color of Rainbow Trout

Abstract The degree of flesh pigmentation is one of the most important quality criteria dictating the fish market value. It is well known that fish, like other animals, cannot synthesize their own coloring pigments de novo, and must obtain these pigments from their diet. In this study, four levels of black mulberry (Morus nigra) juice powder (BMP) as a natural pigment source were incorporated into a basal diet at concentrations of 0, 0.25, 0.5, and 0.75% and fed to rainbow trout weighing 100±5 g for 8 weeks in triplicate. At the end of the feeding trial, the effect of BMP on growth performance, blood biochemical parameters and fillet color was examined. Fish fed BMP showed significant enhancements in weight gain (WG), specific growth (SGR), food conversion ratio (FCR), and survival rates (SR) (P&lt;0.05). SGR, WG and SR values were increased significantly following dietary supplementation with BMP in a dose dependent manner with the highest values in fish fed 0.75%, while the FCR was decreased (P&lt;0.05). Body crude protein, lipid, and moisture contents were increased significantly in fish fed BMP (P&lt;0.05). Dietary BMP has significantly decreased the levels of blood ALT, AST, and glucose (P&gt;0.05). While the blood carotenoid concentration was increased in fish fed 0.5% BMP compared to other treated groups. Fish fed BMP showed increased fillet yellowness (b*) and redness (a*), while the fillet lightness (L*) was decreased when compared to the control (P&lt;0.05). In conclusion, diets supplemented with BMP increased the growth performance, muscle pigmentation, and health status of rainbow trout.

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.

Restoration and conservation of anatomic pieces.

In this study, a restoration process was developed with potassium hydroxide (KOH), in order to improve each of the structures for their posterior fixation, through the use of new methods such as the Chilean conservative fixative solution (SFCCh), with exceptional results. Restore anatomical pieces corresponding to corpse and organs, being these last set with the SFCCh. In this work dealt with processes of restoration with potassium hydroxide, sodium chloride, and sodium hypochlorite, the process began with the cleanliness and suture of the structures for subsequent fixing in Chilean conservative fixative solution, making use of a corpse and different anatomical parts. Work based on items found in the database, Elsevier, Science Direct, ProQuest, and MEDLINE. At the end of the process of restoration and conservation of the anatomical pieces, was observed an improvement in muscle pigment with decrease of rigidity in the specimen, additionally a recovery of appearance in the vascular-nervous elements was achieved. The organs were much more malleable and the structures facilitate the identification of specific details, its subsequent immersion in SFCCh allows the longer preservation of the obtained results. The restoration with potassium hydroxide allows the improvement in the appearance of the different anatomical structures and simultaneously to facilitate its study. The SFCCh is an alternative that replaces partially the use of formaldehyde. In addition, it presents toxicity reduction.

Evaluating Ground Beef Formulated with Different Fat Sources

Objectives were to evaluate effects of fat source and formulated fat percentage on fatty acid composition, lean color stability, lipid oxidation, and aerobic microbial load during simulated retail display of ground beef patties. In Experiment 1 beef carcasses (n = 30) were chilled for 2 d and then fabricated. M. semimembranosus muscles were removed along with 2 fat sources (kidney and pelvic = KP and subcutaneous = S from the same carcass) and ground to achieve 75 and 95% lean. Fatty acid profile and thiobarbituric acid reactive substances (TBARS) were determined over a 7 d simulated retail display period. Saturated fat differed (P = 0.0004) by fat source, with KP having a higher percentage than S. Thiobarbituric acid reactive substances were higher for (P &lt; 0.05) for patties made with S compared to KP. In Experiment 2 beef carcasses (n = 20), were fabricated and blended into ground beef as described in Experiment 1. After designated display time patties were removed and instrumental color measurement, myoglobin concentration, TBARS, and aerobic plate counts (APC) were collected. Oxymyoglobin (OMb) percentage decreased (P &lt; 0.0001) by storage day and had source x formulated fat percentage interaction (P = 0.011). Inversely, storage day increased metmyoglobin (MMb) percentage (P &lt; 0.0001) where d 1 &lt; d 3 &lt; d 5 &lt; d 7, respectively. Changes in myoglobin form contributed to decreased a* values (P &lt; 0.0001) over time. However, APC did not differ (P &gt; 0.05) for d, fat source, or fat percentage. Discoloration in ground beef over 7 d of retail display was more a function of muscle pigment oxidation (OMb to MMb) than aerobic microbial spoilage.

THE EFFECT OF INTRAMUSCULAR FAT CONTENT ON THE MEAT QUALITY OF PLW X PL PIGS

This study aimed to determine the effect of intramuscular fat content (IMF) on the quality of meat from PLW x PL pigs. Meat was evaluated in terms of intramuscular fat content (n=80), technological properties, visual and tactile aspects, and colour measurements. It was demonstrated that meat containing more IMF was characterised by higher tenderness and marbling, but lower water content and a lower proportion of the yellow b* colour. Furthermore, it had a lower C* saturation, a lower h° hue, and lower muscle pigment content.

Transcriptome profile analysis identifies candidate genes for the melanin pigmentation of breast muscle in Muchuan black-boned chicken.

Melanin-based coloration in the meat of black-boned chicken is a major economic issue in China. Variation in the pigmentation (hypopigmentation) of chicken muscle causes direct economic losses every year. To determine the molecular mechanisms involved in the melanogenesis of muscle tissue, this study used high-throughput sequencing to compare differences in the transcriptome between black (BM) and white (WM) chicken breast muscles. We constructed 6 cDNA libraries from BM and WM groups in Muchuan black-boned chickens. A comparison between the BM and WM groups revealed 264 differentially expressed genes, of which 152 were upregulated, whereas 112 were downregulated in black muscle. Gene ontology and a Kyoto Encyclopedia of Genes and Genomes pathway analysis identified several differentially enriched biological functions and processes of the 2 muscles. Seven promising candidate genes [PMEL, Ras-related protein RAB29, and 5 solute carrier superfamily genes: SLC6A9, SLC38A4, SLC22A5, SLC35F3, and SLC16A3] may play an important role in the melanogenesis of chicken muscle. Our data provide a valuable resource for identifying genes whose functions are critical for muscle melanogenesis, and will assist studies of the molecular mechanisms of melanogenesis regulation in chicken muscle.

Genetic effects of fatty acid composition in muscle of Atlantic salmon

BackgroundThe replacement of fish oil (FO) and fishmeal with plant ingredients in the diet of farmed Atlantic salmon has resulted in reduced levels of the health-promoting long-chain polyunsaturated omega-3 fatty acids (n-3 LC-PUFA) eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in their filets. Previous studies showed the potential of selective breeding to increase n-3 LC-PUFA levels in salmon tissues, but knowledge on the genetic parameters for individual muscle fatty acids (FA) and their relationships with other traits is still lacking. Thus, we estimated genetic parameters for muscle content of individual FA, and their relationships with lipid deposition traits, muscle pigmentation, sea lice and pancreas disease in slaughter-sized Atlantic salmon. Our aim was to evaluate the selection potential for increased n-3 LC-PUFA content and provide insight into FA metabolism in Atlantic salmon muscle.ResultsAmong the n-3 PUFA, proportional contents of alpha-linolenic acid (ALA; 18:3n-3) and DHA had the highest heritability (0.26) and EPA the lowest (0.09). Genetic correlations of EPA and DHA proportions with muscle fat differed considerably, 0.60 and 0.01, respectively. The genetic correlation of DHA proportion with visceral fat was positive and high (0.61), whereas that of EPA proportion with lice density was negative. FA that are in close proximity along the bioconversion pathway showed positive correlations with each other, whereas the start (ALA) and end-point (DHA) of the pathway were negatively correlated (− 0.28), indicating active bioconversion of ALA to DHA in the muscle of fish fed high FO-diet.ConclusionsSince contents of individual FA in salmon muscle show additive genetic variation, changing FA composition by selective breeding is possible. Taken together, our results show that the heritabilities of individual n-3 LC-PUFA and their genetic correlations with other traits vary, which indicates that they play different roles in muscle lipid metabolism, and that proportional muscle contents of EPA and DHA are linked to body fat deposition. Thus, different selection strategies can be applied in order to increase the content of healthy omega-3 FAin the salmon muscle. We recommend selection for the proportion of EPA + DHA in the muscle because they are both essential FA and because such selection has no clear detrimental effects on other traits.

Effects of dietary astaxanthin on the growth and skin and muscle pigmentation of sexually immature rainbow trout Oncorhynchus mykiss (Walbaum, 1792) (Teleostei: Salmonidae)

This study was conducted to investigate the effects of dietary synthetic astaxanthin on the growth performance and skin and muscle pigmentation of sexually immature rainbow trout. Four astaxanthin supplemented diets were prepared to contain 50, 100, 150 and 200mg astaxanthin kg -1 diet. The basal diet without astaxanthin supplementation was used as a control. Juvenile rainbow trout of the similar size (20.07±1.45g) were fed with these experimental diets for 30 days. Results showed that there were no significant differences in weight gain, specific growth rate, condition factor, survival rate and feed conversion ratio among all treatments ( P >0.05). The skin carotenoid content was significantly affected by the dietary supplementation ( P <0.05) and the lowest carotenoid content was measured in the treatments of the control and the fish fed 50 mg astaxanthin kg -1 diet ( P <0.05). However, the fish fed 200mg astaxanthin kg -1 diet demonstrated the highest carotenoid content in the skin ( P <0.05). Although the muscle carotenoid content increased in all groups, this augmentation was significantly prominent in the fish received the higher concentration of astaxanthin through the feed. According to the obtained results, it is proposed that in sexually immature rainbow trout, astaxanthin is mainly deposited in muscle in compared to skin. Also, diet supplementation with astaxanthin is necessary for skin pigmentation in rainbow trout.