Flesh Quality Research Articles

THE EFFECTIVENESS OF LIME (Citrus aurantifolia) SOLUTION ON QUALITY OF Pterygoplichthys pardalis FLESH FROM CILIWUNG RIVER, JAKARTA, INDONESIA

Rivers play an important role in life, but they are highly polluted by increased activities in the surrounding. For example, Ciliwung River is experiencing heavy metal pollution which has affected aquatic organisms including the pleco fish widely used by local communities as food ingredients such as dumplings, dimsum, and otak-otak. This element’s content rises in pleco fish flesh yearly and the accumulation after entering the human body interferes with health. Even though the usage of citric acid-containing lime reduces heavy metals, currently, no information explains the fruit’s effectiveness on metal content in pleco fish. Therefore, this research aims to prove the effectiveness of lime solution on pleco fish flesh quality. It was conducted by soaking the fish flesh with control and the lime solution at different concentrations, namely 0, 50, 75, and 100% for 10 and 30 minutes. Proximate analysis was performed followed by metal and mineral content testing through the XRF method. Based on the results, soaking the sample object with a higher concentration of lime and at a longer time caused a decrease in ash content, while water, protein, and fat increased. After soaking, Pb and Hg content had chelation in each treatment but still exceeded the SNI threshold value, while Sn was in accordance with the SNI. The content of macrominerals (K, Cl, Mg, and P) and microminerals (Cu, Zn, and Se) became different.

Effects of dietary chromium yeast levels on growth performance, anti-oxidative capacity, immune response and flesh quality of abalone Haliotis discus hannai

A 110-day feeding trial was conducted to investigate the effects of dietary chromium (Cr) on the growth performance, immune response, anti-oxidative capacity, stress resistance, flesh quality of abalone Haliotis discus hannai. Seven isonitrogenous and isolipidic experimental diets were formulated with graded levels of Cr (0.04, 0.67, 1.21, 1.58, 2.21, 2.72 and 3.33 mg/kg) from Cr yeast. The results showed that weight gain rate (WGR) was highest in the group with 1.21 mg/kg of dietary Cr. Based on the broken-line regression analysis for WGR, the dietary Cr requirement of abalone was estimated to be 1.32 mg/kg. With the increase of dietary Cr level from 0.04 to 1.21 mg/kg, the total anti-oxidative capacity and lysozyme activity in the cell-free hemolymph were increased and then decreased when the dietary Cr level exceeded 1.21 mg/kg. After the challenge of Vibrio parahaemolyticus, the cumulative mortality of abalone was significantly decreased in the group with 1.21 mg/kg of dietary Cr compared with that in the control group. Meanwhile, after the heat stress test, the cumulative mortality of abalone was significantly reduced in the groups with 1.58, 2.21 and 2.72 mg/kg of dietary Cr compared with that in the control group. The liquid and water loss of foot muscle were significantly increased in the groups with 2.72 and 3.33 mg/kg of dietary Cr. With the increase of dietary Cr levels, the hardness of foot muscle was significantly elevated. The chewiness of foot muscle was significantly increased with the increase of dietary Cr level from 0.04 to 1.21 mg/kg, and thereafter showed no significant difference when dietary Cr exceeded 1.21 mg/kg. In conclusion, based on the WGR, dietary Cr requirement of abalone (initial weight: 22.31 ± 0.31 g) was estimated to be 1.32 mg/kg. Appropriate dietary Cr levels (1.21–1.58 mg/kg) had positive effects on growth performance, immune response, anti-oxidation, anti-stress and flesh quality of abalone. Overhigh dietary Cr level (2.72–3.33 mg/kg) decreased the flesh quality. Excessive dietary Cr level (3.33 mg/kg) had a negative effect on the health of abalone.

Quality assessment of yellowtail (Seriola quinqueradiata) meat cultured in an offshore floating flexible facility.

Commercial aquaculture of yellowtail (Seriola quinqueradiata) is challenging, owing to deterioration of aquaculture environments. Offshore aquaculture may be a means of overcoming these problems. Here, we assessed the quality of flesh from offshore yellowtail (OY) bred for 1 year in an offshore floating flexible facility compared with coastal yellowtail (CY) cultured simultaneously in a coastal cage facility. The survival rate of the OY group was 94.46%, which was slightly lower than that of CY (98.18%). The feeding rate (feeding weight/fish weight) of CY was 0.4–0.5, whereas that of OY was only 0.3, possibly because poor weather conditions prevented feeding at the offshore facility. However, final fish weights did not differ significantly between both groups. In sensory tests, OY was inferior to CY in terms of oily taste. The lipid content in CY was significantly higher than that in OY. Hardness analysis revealed that OY muscles were harder than those of CY. There were no significant differences between OY and CY in overall sensory evaluations; thus, OY was judged as having equivalent value as a food product with CY. The redness of dark muscles was not significantly different on day 1 of refrigeration. However, the redness value of OY was significantly higher than that of CY on day 2. The inferior fattiness of OY relative to that of CY can be overcome by improving the feeding method. Therefore, offshore aquaculture with negligible environmental pollution may be effective for further development of aquaculture.

Mangosteen Flesh Condition Detector Based on Microwave Non-destructive Technique Using Spiral Resonator Sensor’s

The mangosteen fruit has a characteristic thick skin, so it is difficult to know the condition of the flesh. Farmer can only know damage to the fruit flesh after the fruit skin had opened. Detection of the quality of the mangosteen flesh can be detected using a sensor capable of penetrating the thickness of the mangosteen rind. Flesh quality detection is carried out based on the S21 value (attenuation of mangosteen flesh value) using a portable device equipped with a sensor and capable of emitting microwaves. The S21 value of the fruit's flesh was measured using a spiral resonator that functioned as a sensor. The prototype device consists of an oscillator circuit, a power splitter, and a phase detector with 2507 MHz. Fruit flesh had divided into two conditions: damaged for fruit flesh with yellow sap or Translucent Flesh Disorder, and suitable condition for clean fruit flesh. The results showed that the fruit flesh had an average S21 value of 7.041 dB for damaged flesh and 6.007 dB for good flesh condition. The difference in the value of S21 had used as a reference for detecting the shape of the fruit flesh, with the detection threshold calculated by the Support Vector Machine, resulting in a threshold value of 6.712 dB.

Synergistic effects of dietary methionine and taurine on growth performance, blood parameters, expression in hepatic sulfur-metabolism genes, and flesh quality of large Nile tilapia

This study aimed to evaluate the growth performance, expression of genes related to the metabolism of sulfur-containing amino acids, and flesh quality of large Nile tilapia (Oreochromis niloticus). Fish (n = 120; 1199 ± 46 g) were randomly distributed into four groups and each fish group was hand-fed a basal diet not supplemented (CON) or supplemented with methionine (MET), taurine (TAU), and methionine and taurine (MET+TAU) until apparent satiety for seven weeks. Compared to CON group, the fish group on the MET diet experienced increased in final body weight, protein retention efficiency, and fillet yield by 62.83 g, 9.82%, and 1.31%, respectively (p < 0.05). These results were linked to the down-regulation of cystathionine β-synthase (CBS) and cysteine dioxygenase (CDO) gene controlled by methionine supplementation. Moreover, up-regulation of the adenosylhomocysteine (AHCY) gene in fish offered TAU diet as a metabolic response to methionine deprivation. Furthermore, taurine prevented color deterioration and increased fillet hardness and chewiness attributes as compared to CON group (p < 0.05). Overall, this study indicated a marked effect of dietary methionine on growth performance, particularly fillet yield, and notable synergic effect of methionine and taurine preventing color deterioration and increasing fillet hardness.

Wheat and Barley Grass Juice Addition to a Plant-Based Feed Improved Growth and Flesh Quality of Common Carp (Cyprinus carpio).

Simple SummarySeveral plant extract additives are being increasingly used in aquaculture for their positive effects on fish growth and immunity. Plant extract additives are called phytogenics. The chemical composition of the additives influences their biological activity. The plant extracts used in this study were wheat grass juice and barley grass juice. Their inclusion in a plant-based diet for common carp improved growth performance and flesh quality. The positive effects of the plant extracts could be attributed to their contents of unsaturated fatty acids, essential amino acids, sugars and organic acids.Phytogenics are plant extract additives used for their bioactive properties. The objective of this study was to assess the effect of plant extracts, wheat grass juice (WGJ) and barley grass juices (BGJ) addition to fish diet on growth and meat quality of common carp. Fish (51 ± 33 g initial weight) were fed for four weeks with three plant-based diets: (1) control feed (Con), (2) control feed supplemented with 2% WGJ (Con+WGJ), and (3) control feed supplemented with 2% BGJ (Con+BGJ). The results showed that the inclusion of the two juices in the plant-based feed stimulated the growth and improved meat quality by lowering the fat and ash content. Feed conversion ratio and condition factor were not affected. There were no significant differences in Fe and Zn contents of meat; however, Cu decreased, while Mn was lower in the Con+WGJ group and higher in the Con+BGJ group compared to Con. A high content of unsaturated fatty acids (FA, oleic acid and linoleic acid) and desirable ratios of saturated/unsaturated FA (0.27–0.29) and Ω6/Ω3 (2.5–2.78) were found in all groups. The juices were characterized in terms of lipid profile and polar compounds by GC-MS technique. The observed positive effects can be attributed to the rich composition of juices that included unsaturated FA, amino acids, sugars and organic compounds.

Effects of dietary taurine amino acid on growth performance, mucosal and immune response, gene expression and antioxidant defence of asian seabass (Lates calcarifer).

The enhancement of fish immune system and growth performance throughout the administration of bio-friendly agents such as diet supplements (taurine) is considered a promising alternative in farmed aquatic species. The present study was aimed to examine the effect of supplementation of dietary taurine (0, 5g-TAU5 and 10g-TAU10) in crystalline form (99% purity) in L. calcarifer juveniles, taking into account growth performance, general health indices and immune related-genes mRNA transcript abundance. The results confirmed that the supplementation of taurine enhances significantly all the growth parameters and a better flesh quality. While the blood biochemical and immunological factors didn't present any significant differences, the expression of growth-related genes showed that IGF-1 was almost 3 times higher in fishes fed diet Tau 5 and Tau 10 compared to the control group. Finally, it can be concluded that at the maximum dose tested (10g) the treatment was effective for Asian seabass. In addition, Tau inclusion in an FM-based diet can increase the productivity parameters along with raising the antioxidant status.

High pressure processing extend the shelf life of milkfish flesh during refrigerated storage

Milkfish has become most often associated with histamine fish poisoning recently in Taiwan, but no information regarding the use of high pressure for preservation on this fish flesh. The microbial quality and physicochemical properties of milkfish flesh pressurized at 200, 300, 400, 500, and 600 MPa for 5 min were evaluated. In addition, the retardation effects in microbial growth and quality loss of pressurized milkfish flesh stored at 4 °C and 15 °C were investigated. The results showed that the L* (lightness), W (whiteness), ΔE (color difference), and texture (hardness, cohesiveness and chewiness) of fish flesh increased significantly with the increase in pressure, whereas the a* (redness) value of samples significantly decreased, indicating that high pressure can cause negative effects in texture and color of fish flesh. Furthermore, the aerobic plate count (APC), psychrotrophic bacteria count (PBC), and coliform decreased with the increase in pressure. The samples pressurized more than 300 MPa had significantly lower levels of total volatile basic nitrogen (TVBN) than unpressurized sample. In addition, high pressure above 300 MPa delayed the production in TVBN and histamine content in milkfish flesh stored at low temperatures (4 °C and 15 °C), whereas the delaying effect on the increase of APC and PBC was significant at higher pressures (>400 MPa). However, compared with 15 °C, high pressure combined with low temperature storage at 4 °C more significantly delayed the changes in microbial and chemical quality. In conclusion, the results indicated that pressurization at 400 MPa for 5 min on milkfish flesh was able to prevent deterioration and quality loss, and extend the shelf life during storage at low temperatures, even though it can cause changes to fish flesh texture and color.

Evaluating dynamic effects of dietary glycerol monolaurate on the productive performance and flesh quality of large yellow croaker (Larimichthys crocea)

The effects of GML (Glycerol monolaurate) supplementation with two level (0.5 and 1.0 g kg−1) on the productive performance and flesh quality of large yellow croaker (360 per group) were investigated during feeding (23,50-days) and fasting stage (23,70-days). The GML supplementation significantly increased body weight after 23-days and crude protein, inosinic acid, and yellowness after 50-days. Moreover, it increased hardness, springiness, and chewiness by increasing the collagen content, myofiber density, and decreasing myofiber diameter. The high GML supplementation increased the total free amino acids, delicate amino acids, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (n-3 PUFA), and EPA + DHA, whereas it decreased the content of saturated fatty acids/unsaturated fatty acids (SFA/UFA). During fasting, better body shape and color were shown were shown at high GML supplementation. Conclusively, high dose GML supplementation exerted promising effects on the productive performance and flesh quality of large yellow croaker.

Growth and Meat Quality of Grass Carp (Ctenopharyngodon idellus) Responded to Dietary Protein (Soybean Meal) Level Through the Muscle Metabolism and Gene Expression of Myosin Heavy Chains.

The aim of this study was to investigate the effect of dietary protein level (soybean meal) on growth performance, flesh quality of grass carp, and the related molecular mechanisms. The results showed that appropriate dietary protein levels improved the growth performance, hardness, and pH of muscle while decreasing muscle crude lipid content and cooking loss and altering the antioxidant capacity and metabolic enzymes activities. In addition, appropriate dietary protein promoted the gene expression of myhc-1, myhc-4, myf5, myod, myog, and fgf6a, whereas inhibited that of myhc-7, myhc-2, mrf4, and mstn. Transcriptome profiling of muscle revealed that the flesh quality-specific differences were related to tight junctions and intramuscular fat (IMF) accumulation. GSEA showed that fatty acid metabolism and oxidative phosphorylation were downregulated in SM5 compared with SM1. To conclude, appropriate protein levels improved the growth and flesh quality by regulating muscle antioxidant capacity and gene expression of myhcs and fat metabolism-related signaling molecules.

Assessment of seed chilling, GA3 foliar application, girdling, and grafting as affecting transition to functional flowering in pumpkin

ABSTRACT Temperature is a factor governing the transition for pumpkin (Cucurbita spp. L) from vegetative to reproductive growth that is necessary for fruit and seed production. Under high-temperature plants may not flower at all. An experiment investigated functional flowering induction of a recalcitrant-to-flower cv. El-Zarka (C. maxima Duchesne) in response to foliar GA3 application, pre-sowing seed chilling, vine girdling, and grafting on rootstock of the ready-to-flower cultivar cv. Kafr El-Battikh (C. moschata Duchesne ex Poir.). The recalcitrant cv. flowered when subjected to all treatments. The best responses were GA3 at 10 mg∙L−1, seed imbibed for 36 h and subjected to chilling (4–5°C) for 12 d, vine girdling of 30-day-old plants, and grafting onto rootstock of 7–10-day-old plants of the ready-to-flower cultivar. Transition to flowering in the ready-to-flower and recalcitrant-to-flower cvs. was consistently accompanied by an elevation in leaf total sugar content. Female flower percent was positively associated with enhanced fruit yield and flesh quality. Isozyme analyses exhibited shared bands for seed chilling with application of GA3 and another between girdling and grafting. The common consistent elevation of leaf total sugar content indicates flowering may be mediated via sugar signaling plus carbohydrates availability (response limiting factor). The methods tested appear to control flowering recalcitrance in pumpkins.

Replacement of Fish Oil by ALA‐Rich Vegetable Oils in Diets of Gilthead Sea Bream: Effect on Final Eating Quality

AbstractThis study assesses the effect of inclusion of n–3 C18 rich oils on nutrient profile and quality of flesh in gilthead seabream (≈ 61.5 g) after feeding isoproteic and isolipidic diets in which camelina seed (CSO) or chia oil (CO) totally or partially replaces fish oil (FO) for 110 days. Fillet fatty acid (FA) profile reflects dietary FA profile, characterized by increased C18 polyunsaturated FA (PUFA) and a reduced highly unsaturated FA, whereas n–3/n–6 ratios are increased in fish fed diets with CSO or CO content. However, indices of atherogenicity and thrombogenicity, calculated from the fillet FA profile as indices for the health quality for consumers, are reduced with dietary addition of CSO or CO due to the increased fillet content of C18 n–3 PUFA in CSO and CO fed fish. In spite of the differences in fillet FA profiles, sensory quality of flesh does not vary among fish from different dietary groups. Instrumental texture and color analyses reveal significantly different values in cooked fillets in comparison to the raw fillets. Overall, dietary inclusion of CSO or CO enhances the nutritional value of fish flesh as well as the production of healthier fillets.Practical Applications: This study suggests fish oil could be totally replaced with camelina or chia oil in the diet of gilthead sea bream without negatively affecting sensory characteristics. The dietary inclusion of these oils could enhance the nutritional quality of fish fillets, and could receive wide application in the aquafeed and animal feed producing sector.

Recent Trends on Tilapia Cultivation and Its Major Socioeconomic Impact among Some Developing Nations: A Review

Tilapia cultivation has been found to be an effective tool for many developing countries for socio-economic development by addressing some important issues like food-security and employment generation. Adoption of tilapia cultivation has increased over the decades because of easy management practice and versatile farming technologies have been observed worldwide. Tilapia gain popularity because of their excellent breeding capabilities, flesh quality, high growth rate, disease resistance and survival capabilities under different farming systems and environmental conditions. Such features boosting up rapid growth of tilapia producing industries in an impactful way, by involving poor and non-poor farming communities in some of the developing countries of Asian, African and South American continents. However, some problems still exists with cultivation of different tilapia varieties; such as the inadequate availability of quality fry, deterioration in seed quality, limited technical knowledge among farming communities and poor marketing strategies especially in some of these developing countries depriving its commercial success to some extent. This review describes a present scenario regarding potentialities and difficulties of commercial adaptation of Tilapia cultivation under socio-economically constrained conditions.

Physicochemical properties and sensory acceptability of different varieties of coconut water and flesh

Coconut water is a sweet and refreshing drink obtained directly from the immature coconut and its flesh is smooth with a jelly-like structure. This study was carried out to evaluate the physicochemical properties and sensory acceptability of different varieties of coconut water and flesh. , The varieties of coconut used in this study were tall, dwarf, and hybrid coconut. Firstly, the weight of the coconuts were determined in which the tall variety was the heaviest coconut compared to the others. Tall coconut also showed a significantly higher amount of water volume and weight of coconut flesh. The dwarf coconut water revealed the highest pH (5.48± 0.02) with the lower titratable acidity (0.045±0.01 %). The highest total soluble solid (4.97±0.15 oBrix) was found in tall coconut. The fructose and glucose content of coconut water were found in a range of 2.70-3.58% and 2.04-3.24%, respectively. Potassium was the most abundant mineral in all coconut samples in which a larger quantity was found in water of tall coconut and flesh of dwarf coconut. The Folin–Ciocalteu method showed that dwarf coconut water (9.07±0.00 mg GAE/100 ml) and hybrid coconut flesh (11.57±0.34 mg GAE/100 g) had higher phenolic content than the others. Hybrid coconut flesh exhibited the lowest crude fat content (18.33±1.22 %) than others. Meanwhile, dwarf and hybrid coconut water were more acceptable and appreciated in terms of taste, sweetness, sourness, and overall acceptability. Although the tall coconut flesh was the least acceptable in terms of taste and texture, all samples' overall acceptability was acceptable. In conclusion, dwarf and hybrid coconut have a big potential to produce high-quality beverages and have a good quality of flesh.

Effects of frozen storage temperature on the quality and oxidative stability of bigeye tuna flesh after light salting

SUMMARYEffects of frozen storage temperature on the quality and oxidative stability of lightly salted tuna were investigated. The bright and vivid colour became totally brown after 4 weeks at −20 °C and 8 weeks at −30 °C, where the a*/b* value decreased from 1.35 to 0.38 and 0.58, respectively. Discoloration and lipid oxidation occurred concurrently in lightly salted tuna flesh, and it was speculated that the oxidation of oxymyoglobin to metmyoglobin exacerbated lipid oxidation and vice versa. Storage at −40 °C or lower temperatures effectively suppressed the discoloration and maintained the high water‐holding capacity and unique textural properties of lightly salted flesh. It was attributed to the reduction in the conformational changes and particularly hydrophobic interactions among proteins, protecting the myoglobin from oxidative damages during frozen storage. Considering the quality maintenance and energy savings, storage at −40 °C was appropriate for lightly salted tuna flesh.

Magnesium supplementation in high carbohydrate diets: Implications on growth, muscle fiber development and flesh quality of Megalobrama amblycephala

This study was conducted to investigate the effects of magnesium (Mg) supplementation on the growth performance, muscle fiber development and flesh quality of Megalobrama amblycephala fed a high-carbohydrate (CHO) diet. In vivo, six experimental diets, a control diet (30% CHO, C), and five Mg supplementation levels (0 (HC1), 200 (HC2), 400 (HC3), 800 (HC4) and 1200 (HC5) mg kg−1, respectively) of high-CHO diet (45% CHO), were formulated and then fed to M. amblycephala (initial weight 43.15 ± 0.43 g) for 13 weeks. Results showed that the HC1 diets remarkably decreased weight gain rate (WGR), specific growth rate (SGR), water holding capacity (WHC), pH 24 h postmortem, collagen content, textural properties (hardness, tenderness, chewiness and resilience), muscle fiber density, succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) activities, as well as transcriptions of ampkα2, pgc-1α, mrf-4, myf-5 and myf-6 compared with the C group, but muscle AMP/ATP ratio, ATPase activities and mstna and mstnb transcription showed an opposite trend. The HC3 group of fish obtained relatively high values of WGR, SGR, muscle lipid and protein content, collagen content, textural properties (hardness, tenderness, chewiness and resilience), fiber density, SDH and MDH activities, AMP/ATP ratio as well as transcriptions of ampkα1, pgc-1α, myod, myog and myf-5 compared with other HC groups. In vitro, the isolated primary hepatocytes from M. amblycephala were assigned into four experimental groups: a control group (5.5 mM glucose, Control), a high glucose group (30 mM glucose, HG), an AICAR group (30 mM glucose + 250 μM AICAR, HGA) and an MgSO4 group (30 mM glucose + 2 mM MgSO4, HGM). Results showed that MgSO4 treatment remarkably increased p-Ampk/t-Ampk ratio, Pgc-1α protein content and transcriptions of ampkα1, ampkα2 and pgc-1α compared with the HG group. Overall, based on regression analysis for SGR, the optimal Mg level of M. amblycephala fed high-CHO diets was 366.67 mg kg-1, which was consistent with the above results that fish fed HC3 diets displayed higher the growth performance, muscle fiber density and flesh quality of M. amblycephala.

Dietary l-carnitine supplementation recovers the increased pH and hardness in fillets caused by high-fat diet in Nile tilapia (Oreochromis niloticus)

The wide use of high-fat diet (HFD) causes negative effects on flesh quality in farmed fish. l-carnitine, a lipid-lowering additive, enhances mitochondrial fatty acid β-oxidation. However its roles in alleviating the effects of HFD on flesh quality in fish are unknown. We fed Nile tilapia with medium-fat diet (MFD, 6% dietary lipid), high-fat diet (HFD, 12% dietary lipid) and HFCD supplemented with l-carnitine (HFCD + 400 mg/kg l-carnitine) for 10 weeks. The HFD-fed fish had higher fat deposition, pH value, myofiber density and flesh hardness than those fed on MFD. However, feeding the fish with the HFCD improved lipid catabolism, which increased significantly lactic acid content and myofiber diameter in muscle, thus reduced pH and hardness values. HFCD also reduced endoplasmic reticulum stress and myofiber apoptosis caused by HFD in the fish. Our study suggests that dietary l-carnitine supplementation alleviates the negative effects of HFD on flesh quality of farmed fish.

Effects of methionine supplementation in plant protein based diet on growth performance and fillet quality of juveniles Yellow River carp (Cyprinus carpio haematopterus)

The 65 days rearing experiment was carried out to investigate the effects of dietary methionine (Met) levels on growth performance and fillet quality of juveniles Yellow River carp, Cyprinus carpio haematopterus . Five diets containing 6.04 g/kg, 9.31 g/kg, 12.09 g/kg, 15.66 g/kg and 18.05 g/kg Met (Met 6.04, Met 9.31, Met 12.09, Met 15.66 and Met 18.05) were respectively fed to experimental carps (initial weight: 21.56 ± 0.46 g) with three replicates per group. The percentage weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), protein efficiency (PE) and condition factor (CF) all elevated at first and then decreased with the increase of dietary Met levels, and all reached the maximum in Met 12.09 group ( P < 0.05). In Met 9.31 group, the shear force, resilience of raw fillet and the firmness, chewiness, cohesiveness, springiness, resilience of cooked fillet all reached the maximum ( P < 0.05), as did the collagen content and the myofiber density in white muscle, and similar trends were observed in the mRNA levels of myogenic differentiation antigen ( MyoD ), Myogenin , myogenic factor 4 ( Mrf4 ) and myosin light chain ( MyLc ) and the protein expression levels of Myogenin, myosin heavy chain (MyHc) and MyLc. The contents of Ile, Leu, Lys, Arg, Asp, Glu, Ala, Tyr, total umami amino acids (UAA, Asp, Glu, Gly and Ala), total essential amino acids (TEAA), total non-essential amino acids (TNEAA) and total amino acids (TAA) reached the maximum in Met 15.66 group ( P < 0.05). In addition, the quadratic regression analysis of PWG, firmness, chewiness and springiness of cooked fillet against dietary Met levels suggested that the appropriate dietary Met levels (crude protein, about 32.5% and crude lipid, about 8.1% in diet) of Yellow River carp (21.5–69.7 g) was estimated to be 12.20 g/kg, 9.54 g/kg, 11.01 g/kg and 13.70 g/kg, respectively. Our study could lay a theoretical and practical foundation for precise nutritional regulation of flesh quality of Yellow River carp. • Dietary methionine levels change the growth and muscle amino acid composition. • Dietary methionine levels change the myofibers diameter and density. • The methionine levels have more obvious effect on cooked than raw fillet in texture.

Replacement of fishmeal by yellow mealworm meal on the growth performance, feed utilisation and quality of large yellow croaker

An 80-day feeding trial was conducted to evaluate the effects of yellow mealworm (Tenebrio molitor, TM) meal as substitute for dietary fishmeal on the growth performance, feed utilisation and flesh quality of large yellow croaker (initial body weight: 189.18±0.13 g). The control diet (TM0) was designed to contain 56% of fishmeal. Based on the TM0, graded levels of TM meal (15, 30, 45, 60, 75 and 100%, respectively) were used to replace fishmeal to formulate the other six experimental diets (TM15, TM30, TM45, TM60, TM75 and TM100), respectively. The results showed that the survival was not significantly affected by dietary TM meal levels (P&gt;0.05). Compared with control group, the final body weight, weight gain rate and protein efficiency ratio decreased significantly when the replacement level over 30%, while feed conversion ratio increased significantly as replacement level over 45% (P&lt;0.05). The total protein-bound amino acid content in muscle was significantly increased with the increase of dietary TM meal inclusion (P&lt;0.05). With replacement level increasing, the percentage of eicosapentaenoic acid (EPA) and Σn-3/Σn-6 poly-unsaturated fatty acids (PUFA) in muscle significantly decreased (P&lt;0.05). Meanwhile, the skin redness (a*) and yellowness (b*) values in the ventral and bottom of ventral regions showed a decreasing and increasing trend, respectively (P&lt;0.05). The TM100 group showed a higher myofibre diameter and lower myofibre density compared to the control group (P&lt;0.05). Total replacement of fishmeal with TM meal significantly down-regulated and up-regulated the expression of myf6 and mstn, respectively (P&lt;0.05). The contents of inosine-5′-monophosphate and total free amino acids were significantly decreased with the increase of TM meal inclusion (P&lt;0.05). In conclusion, TM meal can replace at least 30% of dietary fishmeal protein without negative effects on the growth, feed utilisation and flesh quality of large yellow croaker.

Effects of dietary vitamin E supplementation on growth, feed utilization and flesh quality of large yellow croaker Larimichthys crocea fed with different levels of dietary yellow mealworm Tenebrio molitor meal

An 80-day feeding trial was conducted to evaluate the effect of dietary vitamin E and replacement levels of dietary fish meal (FM) by yellow mealworm Tenebrio molitor (TM) meal on growth, feed utilization and flesh quality of large yellow croaker Larimichthys crocea (initial body weight: 189.20 ± 0.16 g). Six isonitrogenous and isolipidic diets from a two factorial design of 3 × 2 were formulated with three replacement levels of dietary FM by TM (15%, 30% and 45%, respectively) and two levels of vitamin E (150 mg/kg and 500 mg/kg), respectively. The results showed that the growth and feed utilization of large yellow croaker were significantly decreased at 45% replacement level of dietary FM by TM (P < 0.05). Vitamin E supplementation significantly improved the growth and feed utilization, and increased the content of crude protein, vitamin E and ∑n-3 poly-unsaturated fatty acids in the flesh at higher dietary replacement level (>30%) of FM by TM (P < 0.05). Yellowness (b*) in the dorsal, caudal and ventral skin were found to be significantly increased with the increasing dietary vitamin E supplementation (P < 0.05). Protein carbonyl, malondialdehyde, and fiber density significantly decreased at 500 mg/kg of dietary vitamin E, while hardness, gumminess, chewiness and the activities of superoxide dismutase, glutathione-peroxidase, catalase in flesh significantly increased (P < 0.05). The transcript levels of MyoD and myf5 were significantly affected by dietary vitamin E levels (P < 0.05). The present study indicated that 30% of dietary replacement level of FM by TM was practicable in large yellow croaker feed. Meanwhile, dietary vitamin E supplementation improved the flesh quality of large yellow croaker.