Muscle Fat Content Research Articles

Linking genomic prediction of fillet fat content in Atlantic salmon to underlying changes in lipid metabolism regulation

Fillet fat content is an important production trait in Atlantic salmon (Salmo salar) because it influences the flavor, texture, and nutritional properties of the product. Selection can be applied to alter muscle fat content, however how such selection changes the underlying molecular physiology of these animals is unknown. Here, we examine the link between genomic predicted breeding value for fillet fat of 184 fish and gene expression in the liver with an emphasis on lipid metabolism genes. We found that salmon with higher genomic breeding values for fillet fat had higher expression of genes in lipid metabolism pathways. This included key lipid metabolism genes hmgcrab, fasn-b, fads2d5, and fads2d6, and lipid transporters fatp2f, fabp7b, and apobc. We also found several regulators of lipid metabolism with negative correlation to genomic breeding values, including pparg-b, fxr-a, and fxr-b. A quantitative trait loci analysis for variation in gene expression levels (eQTLs) for 167 fillet fat associated genes found that 71 genes had at least one eQTL, and that most were trans eQTLs. Closer examination revealed distinct eQTL clustering on chromosomes 3 and 6, indicating the presence of putative common regulator in these regions. Taken together, these results suggest that salmon with high genomic breeding value for fillet fat have elevated lipid synthesis, elevated lipid transport, and reduced glycerolipid breakdown; and that this is at least partly due to genetic variants that impact the function of top-level transcription factors involved in liver metabolism. Our study sheds light on how genomic selection for reduced or increased fillet fat content in Atlantic salmon alters gene regulation in the liver of the fish. These results could be used to prioritize SNPs with an association to phenotype related gene expression to improve the efficiency and reduce the cost of genomic selection in the future.

Body Composition Indicators Jointly Predict Metabolic Unhealthy Phenotypes in Young and Middle-Aged Obese Individuals: A Cross-Sectional Quantitative Computed Tomography Study.

The main aim of this study is to analyze the relationship between body composition indices and metabolic unhealthy phenotypes in young and middle-aged obese patients and to assess their joint predictive ability. A cross-sectional study method was used to select 207 patients who were proposed to undergo weight loss surgery for morbid obesity from March to November 2022. Total adipose tissue (TAT), visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), liver fat content (LFC), cross-sectional area (CSAmuscle), and intermuscular adipose tissue (CSAIMAT) of paraspinal muscles were measured using quantitative computed tomography. Participants were categorized into two groups: metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO). The receiver operating characteristic curve comprised body composition variables that correlated with MUO, and the area under the curve (AUC) was calculated to compare their prediction capacity for MUO. There were 71 patients with MHO (34.3%) and 136 patients with MUO (65.7%). The VAT, VAT/TAT ratio, LFC, and CSAmuscle was higher in MUO patients than in MHO (all P < 0.001), and SAT was lower than in MHO (P = 0.008). And all of these metrics were correlated with MUO (all P < 0.05). Inclusion of these body composition metrics in the ROC analysis showed that the AUC values for SAT, VAT, VAT/TAT ratio, LFC and CSAmuscle were 0.615, 0.663, 0.727, 0.694, 0.671, respectively, and the combination of the VAT/TAT ratio and the LFC had the ability to predict MUO best (AUC=0.746, P = 0.025). The combined use of VAT/TAT ratio and LFC is superior to the use of these two metrics alone in terms of their ability to predict the MUO, providing a more accurate approach to the management and prevention of obesity-related metabolic risk.

Regional and bilateral MRI and gene signatures in facioscapulohumeral dystrophy: implications for clinical trial design and mechanisms of disease progression.

Identifying the aberrant expression of DUX4 in skeletal muscle as the cause of facioscapulohumeral dystrophy (FSHD) has led to rational therapeutic development and clinical trials. Several studies support the use of MRI characteristics and the expression of DUX4-regulated genes in muscle biopsies as biomarkers of FSHD disease activity and progression. We performed lower-extremity MRI and muscle biopsies in the mid-portion of the tibialis anterior (TA) muscles bilaterally in FSHD subjects and validated our prior reports of the strong association between MRI characteristics and expression of genes regulated by DUX4 and other gene categories associated with FSHD disease activity. We further show that measurements of normalized fat content in the entire TA muscle strongly predict molecular signatures in the mid-portion of the TA, indicating that regional biopsies can accurately measure progression in the whole muscle and providing a strong basis for inclusion of MRI and molecular biomarkers in clinical trial design. An unanticipated finding was the strong correlations of molecular signatures in the bilateral comparisons, including markers of B-cells and other immune cell populations, suggesting that a systemic immune cell infiltration of skeletal muscle might have a role in disease progression.

Effects of quercetin and hydroxytyrosol supplementation in a high-fat diet on growth, lipid metabolism, and mitochondrial function in spotted seabass (Lateolabrax maculatus)

Endoplasmic reticulum (ER) stress and mitochondrial impairment commonly occur during the progression of fatty liver disease. There is a close connection and crosstalk between mitochondria and ER. The potential positive influence of mitigating ER stress (ERS) and mitochondrial damage in the context of preventing and treating fatty liver was explored in spotted seabass (Lateolabrax maculatus) as a susceptible model to fatty liver. A normal-fat diet (11% fat, NFD) and a high-fat diet (17% fat, HFD) were formulated and three additional diets were prepared by supplementation of quercetin (QUE) (0.1%), hydroxytyrosol (HT) (0.02%) or their combination (0.1% QUE + 0.02% HT) to the HFD (HFD + QUE HFD + HT and HFD + QUE + HT diets).Three replicate groups of fish (25 ± 0.02 g) were fed the test diets to visual satiety for 8 weeks. The results revealed the deterioration of growth, feed intake and feed utilization in HFD group compared to the NFD group whereas QUE and HT application improved their values and the optimum results were achieved for the HFD + QUE + HT group. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, and both serum and hepatic triglyceride (TG), total cholesterol (T-CHO) and non-esterified free fatty acids (NEFA) concentrations were enhanced in HFD group, and their values decreased by QUE and HT, particularly their combined supplementation. The results of oil red O staining exhibited a remarkable reduction in number of lipid droplets in the liver of fish from HFD + QUE + HT group compared to the HFD group. Whole-body and muscle fat contents and abdominal fat index decreased by QUE and HT application. Expression of lipid metabolism related genes (srebp-1c, fas, acc) were down-regulated by QUE and HT treatment. Co-supplementation of QUE and HT down-regulated the expression of ERS-related genes (grp78, chop, perk, atf6, ire1), improved ER ultrastructure, and enhanced the coupling between mitochondria and ER. Moreover, expression of genes associated with hepatic mitochondrial biogenesis (pgc1-α, pgc1-β, nrf1) and mitophagy (pink1, atg5, mul1) was up-regulated in HFD + QUE, HFD + HT and HFD + QUE + HT groups. These data suggest that combined supplementation of QUE and HT in HFD for spotted seabass can improve growth and feed utilization, reduce hepatic damage and fat accumulation, and alleviate HFD induced ERS and mitochondrial dysfunction.

Trimethylamine oxide supplementation differentially regulates fat deposition in liver, longissimus dorsi muscle and adipose tissue of growing-finishing pigs

Trimethylamine oxide (TMAO) is a microbiota-derived metabolite, and numerous studies have shown that it could regulate fat metabolism in humans and mice. However, few studies have focused on the effects of TMAO on fat deposition in growing-finishing pigs. This study aimed to investigate the effect of TMAO on fat deposition and intestinal microbiota in growing-finishing pigs. Sixteen growing pigs were randomly divided into 2 groups and fed with a basal diet with 0 or 1 g/kg TMAO for 149 d. The intestinal microbial profiles, fat deposition indexes, and fatty acid profiles were measured. These results showed that TMAO supplementation had a tendency to decrease lean body mass (P < 0.10) and significantly increased backfat thickness (P < 0.05), but it did not affect growth performance. TMAO significantly increased total protein (TP) concentration, and reduced alkaline phosphatase (ALP) concentration in serum (P < 0.05). TMAO increased the α diversity of the ileal microbiota community (P < 0.05), and it did not affect the colonic microbial community. TMAO supplementation significantly increased acetate content in the ileum, and Proteobacteria and Escherichia–Shigella were significantly enriched in the TMAO group (P < 0.05). In addition, TMAO decreased fat content, as well as the ratio of linoleic acid, n-6 polyunsaturated fatty acids (PUFA), and PUFA in the liver (P < 0.05). On the contrary, TMAO increased intramuscular fat content of the longissimus dorsi muscle, whereas the C18:2n6c ratio was increased, and the n-6 PUFA:PUFA ratio was decreased (P < 0.05). In vitro, 1 mmol/L TMAO treatment significantly upregulated the expression of FASN and SREBP1 in C2C12 cells (P < 0.05). Nevertheless, TMAO also increased adipocyte area and decreased the CPT-1B expression in subcutaneous fat (P < 0.05). Taken together, TMAO supplementation regulated ileal microbial composition and acetate production, and regulated fat distribution and fatty acid composition in growing-finishing pigs. These results provide new insights for understanding the role of TMAO in humans and animals.

Monitoring Nusinersen Treatment Effects in Children with Spinal Muscular Atrophy with Quantitative Muscle MRI.

Spinal muscular atrophy (SMA) is caused by deficiency of survival motor neuron (SMN) protein. Intrathecal nusinersen treatment increases SMN protein in motor neurons and has been shown to improve motor function in symptomatic children with SMA. We used quantitative MRI to gain insight in microstructure and fat content of muscle during treatment and to explore its use as biomarker for treatment effect. We used a quantitative MRI protocol before start of treatment and following the 4th and 6th injection of nusinersen in 8 children with SMA type 2 and 3 during the first year of treatment. The MR protocol allowed DIXON, T2 mapping and diffusion tensor imaging acquisitions. We also assessed muscle strength and motor function scores. Fat fraction of all thigh muscles with the exception of the m. adductor longus increased in all patients during treatment (+3.2%, p = 0.02). WaterT2 showed no significant changes over time (-0.7 ms, p = 0.3). DTI parameters MD and AD demonstrate a significant decrease in the hamstrings towards values observed in healthy muscle. Thigh muscles of children with SMA treated with nusinersen showed ongoing fatty infiltration and possible normalization of thigh muscle microstructure during the first year of nusinersen treatment. Quantitative muscle MRI shows potential as biomarker for the effects of SMA treatment strategies.

Impact of Peroxisome Proliferator-Activated Receptor Agonists on Myosteatosis in the Context of Metabolic Dysfunction-Associated Steatotic Liver Disease.

Metabolic dysfunction-associated steatotic liver disease (MASLD), and more specifically steatohepatitis may be associated with fat infiltration of skeletal muscles which is known as myosteatosis. Pan-peroxisome proliferator-activated receptor (PPAR) agonists have been shown to promote metabolic dysfunction-associated steatohepatitis (MASH) remission. However, the effect of PPAR agonists on myosteatosis remains to be determined. The aim of this review is to evaluate the effect that PPAR agonists alone or in combination, have on myosteatosis in the context of MASLD. Original research reports concerning the impact of PPAR agonists on muscle fat in MASLD were screened from PUBMED and EMBASE databases following the PRISMA methodology. Eleven original manuscripts were included in this review. Two preclinical studies assessed the impact of the PPARα agonist on fat content in the quadriceps muscle and the liver by extracting triglycerides in rats fed a high-fat diet and in insulin-resistant mice. Both models showed muscle and liver triglyceride content reduction using WY14643. Fenofibrate had no significant impact on soleus intramyocellular lipids or liver fat content in insulin-resistant subjects based on proton magnetic resonance spectroscopy. Treatment with PPARδ agonists increased the expression of genes involved in fatty acid oxidation in two studies on muscle cell culture. PPARγ agonists were investigated in two preclinical studies and one clinical study using spectroscopy and computed tomography respectively. In the first preclinical study in Zucker diabetic fatty rats, rosiglitazone reduced muscle lipids and hepatic steatosis. In a second preclinical study using the same animal model, pioglitazone reduced tibialis anterior intramyocellular lipids. In contrast, computed tomography analyses in patients with type 2 diabetes revealed a surface area increase of low-density muscles (suggesting an increase in muscle fat content) after a one-year treatment with rosiglitazone. Varying combinations of PPAR agonists (cevoglitazar, fenofibrate/pioglitazone and muraglitazar) were evaluated in two preclinical studies and one clinical study. In rats, these treatments showed variable results for muscle and liver depending on the combinations studied. In type 2 diabetic patients, treatment with muraglitazar (a PPARα/γ agonist) reduced the intramyocellular lipid content of tibialis anterior as well as liver fat content following spectroscopy assessment. The combination of different PPAR agonists could have a positive impact on reducing myosteatosis, in addition to their effect on the liver. Some discrepancies could be explained by the different techniques used to assess muscle lipid content, the muscles assessed and the possible adipogenic effect of PPARγ agonists. Further clinical research is needed to fully assess the efficacy of these treatments on both MASLD progression and associated myosteatosis.

Comparative Evaluation of Imaging Techniques for Paraspinal Muscle Fat Quantification

Introduction: Low back pain (LBP) is a prevalent health issue associated with morphological changes in paravertebral muscles. Magnetic resonance imaging (MRI) is effective in identifying muscle steatosis, with MR spectroscopy (MRS) considered the gold standard. However, MRS is limited by technical challenges, prompting interest in Dixon sequences for fat quantification. Materials and Methods: We conducted a study comparing Multi Echo VIBE Dixon with single-voxel MR spectroscopy in quantifying fat fractions in lumbar multifidus muscles of chronic LBP patients. Ninety-eight measurements from 49 patients were analysed. Qualitative and quantitative image analyses were performed, and statistical analysis was conducted using SPSS 27. Results: Significant positive correlation (correlation coefficient: 0.992, p &lt; 0.001) was found between Dixon and MRS fat fraction measurements. Intra-class correlation coefficient was 0.991 (p &lt; 0.001), indicating strong agreement. No proportion bias was observed. Factors such as age, sex, and spinal degeneration correlated positively with multifidus fat atrophy. Conclusion: T2*-corrected Dixon imaging aligns well with spectroscopic measurements, offering an accurate alternative for estimating paraspinal muscle fat content in chronic LBP patients. Further studies are needed to establish threshold values for Dixon imaging. Chronic LBP is associated with multifidus muscle atrophy and fat infiltration, highlighting the need for effective management strategies.

Влияние зимовки на морфофизиологические и химические показатели судака Sander lucioperca

During the wintering period, sander from their natural habitat and grown in farm conditions undergo changes in morphophysiological and chemical status due to the expenditure of energy reserves of the body and the redistri-bution of nutrients in the muscles and liver. This is expressed in a significant decrease in the content of ab-dominal fat in the body of wild and factory individuals (by 45 and 16%, respectively), muscle fat content (by 26% in wild individuals) and liver (by 59% in wild and 16% in farm fish), vitamin C in muscles (by 56 and 23%, respectively). At the same time, the content of nitrogen–free extractives in the muscles and liver increases many times – by 47 and 31%, respectively, in wild individuals and by 31 and 29% in sander raised in cages. The proportion of monounsaturated fatty acids in the lipids of sander muscles in winter significantly increases and the proportion of polyunsaturated fatty acids (PUFA) decreases, especially eicosapentaenoic (EPA), docosahexaenoic (DHA) and arachidonic, against the background of an increase in the level of these acids in the liver. From the point of view of meat quality, estimated by the content of long-chain PUFA, during the wintering period there is a significant decrease in the nutritional value &#x0D; of caught and raised fish, which is expressed in a 2-3-fold decrease in EPA + DHA in fillets. Such changes are the adaptation of fish to cold temperature conditions during prolonged wintering and are associated with puberty.

Relationship between intramuscular fat content in the quadriceps muscle and clinical severity in patients with knee osteoarthritis

To explore relationship between intramuscular fat content of quadriceps femoris and clinical severity of knee osteoarthritis (KOA). Totally 30 KOA patients were selected from February 2021 to June 2021, including 6 males and 24 females, aged with an average of (64.20±9.19) years old, and body mass index (BMI) was (24.92±3.35) kg·m-2. Patients were divided into relative severe leg (RSL) and relative moderate leg (RML) according to severity of pain on visual analogue scale(VAS). Musculoskeletal ultrasound was used to collect muscle images of quadriceps muscles on both sides of the patient, and Image J was used to analyze echo intensity (EI) of each muscle. Both VAS and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were used to assess pain and function. Quadriceps muscle EI on both sides of patients was compared. Pearson correlation analysis was conducted to analyze correlation between quadriceps muscle EI value between RSL and RML, and linear regression was used to analyze relationship between each muscle EI and VAS and WOMA scores of patients. The EI of RSL lateral vastus lateralis (VL) was 123.78±36.25 and RSL vastus medialis (VM) was 109.46±30.36 which were significantly higher than those of 108.03±31.34 and 93.32±26.04 of RML (P<0.05), but there was no statistical significance in EI values of rectus femoris (RF) on both sides (P>0.05). EI values of VL and VM on both sides were significantly correlated (P<0.05). There was a significant positive correlation between VM EI value and VAS score in RSL and RML (P<0.05). VM EI values in RSL were positively correlated with total WOMAC (P<0.05), and VM VL EI values in RML were positively correlated with total WOMAC score (P<0.05). Intramuscular fat content of quadriceps is closely related to severity of clinical symptoms in KOA patients, and the most obvious one is VM. Therefore, the intramuscular fat content of quadriceps may be an objective indicator to evaluate severity of KOA patients. At the same time, reducing intramuscular fat content of the quadriceps muscle of KOA patients may be a new direction for the prevention and treatment of KOA.

The cross-sectional area of erector spinae muscle and the liver-to-spleen ratio are associated with frailty in older patients with diabetes: a cross-sectional study

BackgroundOlder patients with diabetes mellitus are more susceptible to frailty. Although some imaging markers of appendicular skeletal muscle mass obtained using dual-energy X-ray absorptiometry or computed tomography (CT) imaging can reflect frailty status, the association between imaging indices obtained by abdominal CT scans and frailty in older inpatients has not been reported.MethodsA total of 151 older inpatients with diabetes mellitus (median age, 79 years; men, 42%) who underwent abdominal CT scans close to the admission date were studied to examine the associations between abdominal CT indices and frailty. Two frailty definitions were used: the modified Cardiovascular Health Study (mCHS) criteria and Kihon Checklist (KCL) criteria. Using the imaging analysis software SYNAPSE VINCENT®, we compared the cross-sectional areas (CSA) of four truncal muscles (erector spinae, iliopsoas, rectus abdominis, and abdominal oblique muscles) and the liver-to-spleen ratio (L/S), the ratio of the CT values of the liver and spleen between frail and non-frail patients. The muscle areas that showed the strongest associations with frailty were also investigated in relation to grip strength and walking speed. Finally, multivariate binominal logistic regression analyses were performed to assess the independent associations of CSA of muscle and L/S with the prevalence of frailty.ResultsThe prevalence of frailty defined by the mCHS and KCL criteria was 55% and 52%, respectively. The CSA of the erector spinae muscle was most significantly associated with frailty, and was significantly smaller in both sexes of mCHS-defined frail patients and in men with KCL-defined frailty. The CSA of erector spinae muscle was also positively correlated with grip strength and walking speed. In contrast, the L/S was higher in men with KCL-defined frailty. Multivariate logistic regression analyses revealed that the CSA of the erector spinae muscle was independently associated with mCHS-defined frailty in women, and the L/S was associated with KCL-defined frailty in men.ConclusionsThe CSA of erector spinae muscle and low liver fat content could be indices of frailty in older patients with diabetes.

The Effect of Dietary Supplementation with GUAR (Cyamopsis tetragonoloba) Meal Protein on the Quality and Chemical Composition of Pig Carcasses

Abstract Recent research efforts have focused on replacing expensive imported genetically modified soybean meal (GM SBM) as a protein source in animal diets with guar meal characterized by similar nutritional characteristics, which could improve meat quality. The aim of this study was to determine the effect of guar meal protein fed to pigs on carcass quality and the content of major nutrients and fatty acids in the longissimus lumborum (LL) muscle. Pigs were divided into four groups. Control group (1) animals were fed diets containing SBM as the main protein source. In diets for experimental groups 2, 3 and 4, SBM protein was replaced with guar meal protein in 25%, 50% and 75%, respectively. It was found that SBM replacement with guar meal protein at 25% affected carcass weight and the lean content, fat content and protein content of the ll muscle. An analysis of linear correlations revealed a strong negative correlation between the concentrations of monounsaturated fatty acids (MUFAs) and saturated fatty acids (SFAs) in the LL muscle of pigs fed diets containing 25% of guar meal protein, which is nutritionally desirable. The results of this study suggest that the dietary inclusion of guar meal protein at up to 25% of SBM protein has no negative effects on the fattening performance of pigs. Meat quality was not affected by diets fortified with guar meal protein.

Muscle Fat Content Is Associated with Nonalcoholic Fatty Liver Disease and Liver Fibrosis in Chinese Adults.

Several studies have linked myosteatosis with nonalcoholic fatty liver disease (NAFLD) in individuals with obesity. The clinical significance of myosteatosis in individuals with NAFLD in the general population has not been well investigated. Here, we wanted to explore and compare the associations of NAFLD and liver fibrosis with muscle fat content and skeletal muscle mass (SMM) in a relatively large general population in China. We retrospectively included all participants who underwent abdominal CT scans in our health promotion center between April 2021 and October 2021. Muscle fat content was assessed by abdomen quantitative computed tomography (QCT) scans, and SMM was evaluated by bioelectrical impedance. NAFLD was assessed by ultrasonography. The NAFLD fibrosis score (NFS) and Fibrosis-4 Index (FIB-4) score were calculated to assess liver fibrosis. Compared with participants without NAFLD, patients with NAFLD showed significantly increased intermuscular adipose tissue (IMAT%) (7.40±3.37% vs. 6.76±2.66%, P <0.01). According to a multiple logistic regression model, IMAT% (OR=1.091, 95% CI 1.030-1.155, P=0.003) was only independently correlated with NAFLD in obese participants. Mediation analysis showed that BMI mediated the association between IMAT% and NAFLD. In participants with NAFLD, increased IMAT% was independently associated with an increased intermediate to high risk of advanced fibrosis assessed by the NFS or FIB-4 score after adjusting for multiple potential confounders. However, SMM was only independently correlated with an intermediate to high risk for advanced fibrosis evaluated by the NFS and not by the FIB-4 score. Increased muscle fat content is positively correlated with NAFLD and intermediate to high risk for advanced fibrosis in the general Chinese population.

Effect of Tea Polyphenols, α-Lipoic Acid and Their Joint Use on the Antioxidant and Lipid Metabolism Performance of Hybrid Grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) Fed with High-Lipid Diets.

This study investigated tea polyphenols (TP), α-lipoic acid (ALA) and their joint use on the antioxidant and lipid metabolic performance of hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) took food with high-fat diets. Six high-lipid diets with isonitrogen (50% of dry matter) and isolipid (17% of dry value) were designed, in which a total content of 1,000 mg/kg additives were added to each group except for the control group (FL). The additives addition ratios in each group were ALA (AL), TP (PL), ALA : TP = 1 : 1 (EL), ALA : TP = 1 : 2 (OL), ALA : TP = 2 : 1 (TL). Each diet was divided into three repeat groups with 30 tails (6.84 ± 0.01 g) in each group and fed for 8 weeks. The consequences were as follows: (1) the highest weight gain rate, specific growth rate, as well as the lowest feed conversion ratio and ingestion rate were discovered in the OL team, which were opposite to the TL group. (2) The body fat content and muscle fat content in the fish oil group were the lowest (P < 0.05), while those of the TL group were the highest. (3) Serum catalase, glutathione peroxidase, total antioxidant capacity, and superoxide dismutase activities were the highest, and the content of reactive oxygen species was the lowest in the OL group. (4) The OL group has the highest hepatic lipase activity and the lowest very low-density lipoprotein content of the liver. In contrast, the TL group had the highest fatty acid synthetase (FAS) activity (P < 0.05). (5) The oil-red aspects of liver tissue displayed lipid particles in other groups were reduced to different degrees compared with FL group, and the OL group showed the best lipid-lowering effect. (6) Compared with the FL group, the relative expressions of FAS, acetyl-CoA carboxylase (acc), and apolipoprotein b-100 (apoB100) genes in the liver were decreased. The relative expressions of lipoprotein lipase (lpl) and peroxisome proliferators-activated receptors-α (pparα) genes related to lipid catabolism were increased, among which the OL group had the most significant change (P < 0.05). (7) According to the 7-day challenge test of Vibrio alginolyticus, the OL group had the highest survival rate. To sum up, both ALA and TP have positive effects on relieving the lipid metabolism disorder of hybrid grouper. If they are jointly used, adding ALA : TP in a ratio of 1 : 2 (OL) may have the best effect, and an addition ratio of 2 : 1 (TL) may inhibit the hybrid grouper growth and increase the feeding cost.

The Identification of Functional Genes Affecting Fat-Related Meat Traits in Meat-Type Pigeons Using Double-Digest Restriction-Associated DNA Sequencing and Molecular Docking Analysis.

The Chinese indigenous Shiqi (SQ) pigeon and the imported White King (WK) pigeon are two meat-type pigeon breeds of economical and nutritional importance in China. They displayed significant differences in such meat quality traits as intramuscular fat (IMF) content and fatty acid (FA) compositions in the breast muscles. In this study, we aimed to screen candidate genes that could affect fat-related meat quality traits in meat-type pigeons. We investigated the polymorphic variations at the genomic level using double-digest restriction-associated DNA (ddRAD) sequencing in 12 squabs of SQ and WK pigeons that exhibited significant inter-breed differences in IMF content as well as FA and amino acid compositions in the breast muscles, and screened candidate genes influencing fat-related traits in squabs through gene ontology analysis and pathway analysis. By focusing on 6019 SNPs, which were located in genes with correct annotations and had the potential to induce changes in the encoded proteins, we identified 19 genes (ACAA1, ACAA2, ACACB, ACADS, ACAT1, ACOX3, ACSBG1, ACSBG2, ACSL1, ACSL4, ELOVL6, FADS1, FADS2, HACD4, HADH, HADHA, HADHB, MECR, OXSM) as candidate genes that could affect fat-related traits in squabs. They were significantly enriched in the pathways of FA metabolism, degradation, and biosynthesis (p < 0.05). Results from molecular docking analysis further revealed that three non-synonymous amino acid alterations, ACAA1(S357N), ACAA2(T234I), and ACACB(H1418N), could alter the non-bonding interactions between the enzymatic proteins and their substrates. Since ACAA1, ACAA2, and ACACB encode rate-limiting enzymes in FA synthesis and degradation, alterations in the enzyme-substrate binding affinity may subsequently affect the catalytic efficiency of enzymes. We suggested that SNPs in these three genes were worthy of further investigation into their roles in explaining the disparities in fat-related traits in squabs.

Multi-Enzyme Supplementation to Diets Containing 2 Protein Levels Affects Intramuscular Fat Content in Muscle and Modulates Cecal Microflora Without Affecting the Growth Performance of Finishing Pigs.

We investigated the effects of crude protein (CP) levels and exogenous enzymes on growth performance, meat quality, toxic gas emissions, and colonic microbiota community in 200 finishing pigs. Four groups corresponded to 4 diets: 16.74% CP (high-protein level, HP) and 14.73% CP (medium protein level, MP) diet supplemented with or without 1-g/kg multi-enzymes (ENZs, including 1000-U/kg protease, 2500-U/kg α-amylase, and 10,000-U/kg β-glucanase), using a 2 × 2 factorial arrangement. After 7weeks of trial, ENZs supplementation increased (P < 0.05) the average daily gain (ADG) of finishing pigs during weeks 4 to 7 and in the overall period and improved gross energy utilization. Dietary HP improved (P < 0.05) ADG during the overall period. The MP diet-treated pigs had higher intramuscular fat (IMF) content in the longissimus dorsi muscle (P < 0.01). ENZs supplementation to the MP diets lowered muscle IMF content (P < 0.01). Additionally, pigs fed the HP diet released (P < 0.05) more NH3 and H2S in excrement. The HP diet enhanced (P < 0.05) intestinal microbial richness, represented by higher observed_ amplicon sequence variants and Chao1. Administration of ENZs to the HP diet increased (P < 0.05) the Shannon and Pielou's evenness. Dietary MP promoted Firmicutes proliferation. Supplementary HP diet increased the relative abundances of Spirochaetota, Verrucomicrobiota, Desulfobacterota, and Fibrobacterota (P < 0.05). Supplemental ENZ elevated (P < 0.05) Actinobacteriota and Desulfobacterota abundances. ENZ supplementation to the HP diet increased the abundances of Bacteroidota, Desulfobacterota, and Proteobacteria but lowered their abundances in the MP diet. Taken together, the HP diet or ENZs' supplements improved growth performance. Although the interaction between CP levels and ENZs had no effect on growth performance, it modulated colonic flora and muscle IMF content.

Effect of TG5 and LEP polymorphisms on the productivity, chemical composition, and fatty acid profile of meat from Simmental bulls.

Enhancing the nutritional and biological value of meat obtained from young surplus replacement animals of dual-purpose breeds is a critical objective in the livestock industry. This study aimed to investigate the impact of thyroglobulin (TG5, c. -422C > T) and leptin (LEP, c. 239C > T) polymorphisms on the productivity, chemical composition, and fatty acid (FA) profile of meat from Simmental bulls. A total of 26 Simmental bulls were genotyped for TG5 (c. -422C > T) and LEP (c. 239C > T) polymorphisms and reared under the same fattening conditions. Controlled slaughter was conducted at 18 months of age. Subsequently, the experimental animals were evaluated to determine their slaughter traits and the chemical and FA composition of ground beef and the longissimus dorsi muscle. The results showed that the TG5 (c. -422C > T) polymorphism significantly (p < 0.05) affected the differentiation of bulls in terms of the synthesis of stearic acid, linolenic acid, and total polyunsaturated FAs, as well as the fat and dry matter content in the longissimus dorsi muscle. Conversely, the presence of the T allele in the LEP (c. 239C > T) polymorphism was associated with increased dry matter and fat in ground beef, carcass weight, and internal fat weight. The analysis of slaughter traits and the chemical and FA composition of meat from the Simmental bulls genotyped for the TG5 and LEP genes revealed a genetic basis for the quantitative and qualitative characteristics of meat productivity. Thus, the genetic variability of bulls regarding the LEP and TG5 genes can be used to improve the quantitative and qualitative indicators of meat productivity in Simmental cattle through marker-assisted selection.

Effects of dietary niacinamide and CP concentrations on the nitrogen excretion, growth performance, and meat quality of pigs.

Reducing the dietary CP concentration in the formulation of low-protein diets without adverse effects on animal growth performance and meat quality remains challenging. In this study, we investigated the effects of nicotinamide (NAM) on the nitrogen excretion, growth performance, and meat quality of growing-finishing pigs fed low-protein diets. To measure the nitrogen balance, we conducted two trials: in nitrogen balance trial 1, four crossbred (Duroc×Landrace×Large White) barrows (40±0.5kg BW) were used in a 4×4 Latin square design with four diets and periods. The diets consisted of a basal diet+30mg/kg NAM (a control dose), basal diet+90mg/kg NAM, basal diet+210mg/kg NAM, and basal diet+360mg/kg NAM. In nitrogen balance trial 2, another four barrows (40±0.5kg BW) were used in a 4×4 Latin square design. The diets consisted of a basal diet+including 30mg/kg NAM (control), basal diet+360mg/kg NAM, low-protein diet+30mg/kg NAM, and low-protein diet+360mg/kg NAM. To measure growth performance, two trials were conducted. In growth performance trial 1, 40 barrows (37.0±1.0kg) were randomly allocated to one of four dietary treatments (n=10 per group), whereas in growth performance trial 2, 300 barrows (41.4±2.0kg) were randomly allocated to one of four dietary treatments, with each dietary treatment conducted in five repetitions with 15 pigs each. The four diets in the two growth performance trials were similar to those in nitrogen balance trial 2. Supplementing the diet with 210 or 360mg/kg NAM reduced urinary nitrogen excretion and total nitrogen excretion and increased nitrogen retention comparted with the control diet (P<0.05). Compared with the control diet, the low-protein diet with 360mg/kg NAM reduced faecal, urinary, and total nitrogen excretion (P<0.05) without affecting nitrogen retention and average daily gain (P>0.05). Pigs fed the low-protein diet with 360mg/kg NAM showed a decreased intramuscular fat content in the longissimus thoracis muscle when compared with pigs fed the control diet (P>0.05). Our results suggest NAM as a suitable dietary additive to reduce dietary CP concentration, maximise nitrogen retention and growth performance, and decrease fat deposition in pigs.

Insights into the mechanism of growth and fat deposition by feeding different levels of lipid provided by transcriptome analysis of swamp eel (Monopterus albus, Zuiew 1793) liver.

Lipid is an important source of energy in fish feeds, and the appropriate fat content can improve the efficiency of protein utilization. However, excessive lipid content in the feed can lead to abnormal fat deposition in fish, which has a negative effect on the growth of fish. Therefore, the effects of feed lipid levels on swamp eel were studied. Essential functional genes were screened using transcriptomics. We divided 840 fish into seven groups (four replicates). A mixture of fish and soybean oils (1:4), 0%, 2%, 4%, 6%, 8%, 10%, and 12% was added to the basic feed were named groups one to seven (L1-L7), respectively. Isonitrogenous diets were fed swamp eel for 10 weeks. Growth performance, visceral index, nutritional components, and biochemical indexes were measured and analyzed. Livers of the 0%, 6%, and 12% groups were subjected to transcriptome sequencing analysis. The results of our study showed that: the suitable lipid level for the growth of swamp eel was 7.03%; the crude fat content of whole fish, liver, intestine, muscle, and skin increased with the increase of lipid level, with some significant difference, and excess fat was deposited in skin tissue; triglyceride, total cholesterol, and free fatty acid contents increased with the increase of feed lipid level. High-density lipoprotein levels in the L3 and L4 groups were higher than in the other groups. Blood glucose concentrations in the L5, L6, and L7 groups increased; the liver tissue structure was damaged when the lipid level was too high. two-hundred-and-twenty-eight differentially expressed genes were found. Several critical pathways regulating glucose metabolism and energy balance (e.g., glycerolipid metabolism, glycolysis synthesis, degradation of ketone bodies, and Janus Kinase/Signal Transducer and Activator of Transcription signaling pathway) were enriched in swamp eel compared with the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Suitable lipid levels (7.03%) can promote the growth of swamp eel, and excessive lipid levels can cause elevated blood lipids and lead to liver cell damage. Regulatory mechanisms may involve multiple metabolic pathways for glucose and lipid metabolism in eels. This study provides new insights to explain the mechanism of fat deposition due to high levels of lipid and provides a basis for the production of efficient and environmentally friendly feed for swamp eel.

Nutritional composition of three commercially important brackish water fish species recorded from Batticaloa Lagoon, Sri Lanka

Fish is a high-quality animal-source food in the nourishment of millions worldwide. The most edible part of the fish is the muscle and which provides a proper balance of proximate and non-proximate nutrition and has a relatively low caloric value than other meats. The present study aimed to fill the gaps in the nutritional profile of three brackish water fishes (<em>Arius maculatus</em>, <em>Mugil cephalus </em>and <em>Oreochromis niloticus</em>) sourced from Batticaloa Lagoon, Sri Lanka. The study was conducted from November 2019 to February 2020 and fish were sampled from Kallady, Kattankudy and Arayampathy fish markets. The nutritional compositions such as moisture content, protein content, fat content and ash content of epaxial muscles of selected fishes were analyzed with standard methods. The moisture content was high among the fish muscles ranging from 56.73 ± 5.96% to 81.48 ± 2.52%. The protein content of A. <em>maculatus</em>, M. <em>cephalus </em>and O. <em>niloticus </em>muscles ranged as 15.36 ± 1.62%, 17.33 ± 1.96% and 13.7 ± 1.55% respectively. Amidst the selected fishes, O<em>. niloticus </em>is a lean fish (1.27 ± 0.35%) while A<em>. maculatus </em>(3.20 ± 0.59%) and M<em>. cephalus </em>(2.43 ± 0.37%) are low-fat fishes based on the muscle lipid content. The ash content of A. <em>maculatus</em>, M. <em>cephalus </em>and O. <em>niloticus </em>ranged from 1.22 ± 0.15% to 1.77 ± 0.45%, respectively. All the measured proximate parameters were significantly different (<em>P</em>-value &lt; 0.05%) among the three fish species. The results of this study revealed that the A. <em>maculatus </em>contains the highest value of lipid and ash content while O. <em>niloticus </em>contains higher amount of moisture content. The M. <em>cephalus </em>can considered as a good source of animal protein compared to the other two fish species.