Effects of dietary oat supplementation on carcass traits, muscle metabolites, amino acid profiles, and its association with meat quality of Small-tail Han sheep

N-acetyl-l-methionine dietary supplementation improves meat quality by oxidative stability of finishing Angus heifers

Methionine plays a vital role in protein synthesis, and regulation of antioxidant response in ruminants. This study aimed to assess the effects of dietary supplementation with N-acetyl-l-methionine (NALM), which serves a source of rumen-protected methionine, on growth performance, carcass traits, meat quality, and oxidative stability. Sixty Angus heifers (initial body weight = 408 ± 51.2 kg, 15-18 months) were stratified by body weight and randomly assigned to four dietary treatments: a control group (0% NALM), and experimental groups receiving diets containing 0.125%, 0.25%, and 0.50% NALM (dry matter (DM) basis), respectively. The experiment included a 2-week adaptation and a 22-week data and sample collection period. Results indicated that blood urea nitrogen in the plasma of the 0.25% NALM group was lower compared to the control and the 0.50% NALM groups (P = 0.02). The plasma methionine (P = 0.04), proline (P < 0.01), and tryptophan (P = 0.05) were higher in the 0.25% and 0.50% NALM groups, as well as the methionine and proline in the muscle of the 0.25% NALM group (P < 0.01). The muscle pH (P < 0.01) was increased by supplementing 0.25% and 0.50% NALM in diets but decreased the lactate (P < 0.01). The 0.25% NALM group also increased a* (P = 0.05), decreased L* (P = 0.05), drip loss (P = 0.01), and glycolytic potential in the muscle (P < 0.01). The total antioxidant capacity, superoxide dismutase, glutathione peroxidase, catalase, and glutathione in muscle of 0.25% NALM group were higher than that of the control (P < 0.01), and the malondialdehyde and protein carbonyl were lower (P < 0.01). In conclusion, the dietary supplement with NALM improves meat quality by enhancing the antioxidant effect of lipids and proteins.

Characterization and discrimination of lamb with different breeds and muscle types using precursors and volatile compounds

The unique aromas of mutton stem from the chemical reactions between the characteristic precursors during cooking. This study aimed to establish the relationship of volatile compounds and aroma precursors (protein, fat, free amino acids and fatty acids) in lamb from different breeds and muscle types. Hong lamb was characterized by greater tenderness and water holding capacity, higher polyunsaturated fatty acids and higher essential/non-essential amino acids in comparison with Hu lamb. Aldehydes, such as heptanal, hexanal, octanal and nonanal were higher in Hong-ST compared with Hu-ST. Principal component analysis (PCA) showed that aroma precursors were closely related to volatile components of cooked lamb. Discriminant analysis results showed that precursors and volatile compounds could be used to identify the breeds and muscle types of lamb. These findings revealed the contributors of lamb aroma and might help understand the regulatory mechanism of aroma in lamb from different breeds and muscle types.

Preliminary studies on the molecular mechanism of intramuscular fat deposition in the longest dorsal muscle of sheep

BACKGROUND

Intramuscular fat content is an important index reflecting the quality of mutton, which directly affects the flavor and tenderness of mutton. Livestock and poultry intramuscular fat content is influenced by genetics, nutritional level, and environmental factors. Key regulatory factors play a crucial role in intramuscular fat deposition. However, there is a limited amount of research on the identification and function of key genes involved in intramuscular fat content deposition specifically in sheep.

RESULTS

Histological differences in the longest dorsal muscle of the small-tailed frigid sheep increased in diameter and decreased in several muscle fibers with increasing monthly age; The intramuscular fat content of the longest dorsal muscle of the small-tailed cold sheep varied with age, with a minimum of 1 month of age, a maximum of 6 months of age, and a minimum of 12 months of age. Transcriptomic sequencing and bioinformatics analysis revealed a large number of differential genes in the longest dorsal muscles of little-tailed billy goats of different months of age, which were enriched in multiple GO entries and KEGG pathways. Among them, the pathway associated with intramuscular fat was the AMPK signaling pathway, and the related genes were PPARGC1A and ADIPOQ; Immunohistochemical studies showed that PPARGC1A and ADIPOQ proteins were expressed in connective tissues, cell membranes, and, to a lesser extent, the cytoplasm of the longest dorsal muscle of the little-tailed frigid sheep; Real-time PCR and Western Blot validation showed that PPARGC1A and ADIPOQ were both expressed in the longest dorsal muscle of the little-tailed frigid sheep at different ages, and there were age differences in the amount of expression. The ADIPOQ gene was negatively correlated with the intramuscular fat content of the longest dorsal muscle, and the PPARGC1A gene was positively correlated with the intramuscular fat content of the longest dorsal muscle; As inferred from the above results, the ADIPOQ gene was negatively correlated with the intramuscular fat content of the longest dorsal muscle (r = -0.793, P < 0.05); and the PPARGC1A gene was positively correlated with the intramuscular fat content of the longest dorsal muscle r = 0.923, P < 0.05).

CONCLUSIONS

Based on the above results, it can be inferred that the ADIPOQ gene is negatively correlated with the intramuscular fat content of the longest back muscle (r = -0.793, P < 0.05); the PPARGC1A gene is positively correlated with the intramuscular fat content of the longest back muscle (r = 0.923, P < 0.05).

A new green approach to L-histidine and β-alanine analysis in dietary supplements using rapid and simple contactless conductivity detection integrated with high-resolution glass-microchip electrophoresis

The analysis of dietary supplements is far less regulated than pharmaceuticals, leading to potential quality issues. Considering their positive effect, many athletes consume supplements containing L-histidine and β-alanine. A new microfluidic method for the determination of L-histidine and β-alanine in dietary supplement formulations has been developed. For the first time, capacitively coupled contactless conductivity detection was employed for the microchip electrophoresis of amino acids in real samples. A linear relationship between detector response and concentration was observed in the range of 10-100 µmol L-1 for L-histidine (R2 = 0.9968) and β-alanine (R2 = 0.9954), while achieved limits of detection (3 × S/N ratio) were 4.2 µmol L-1 and 5.2 µmol L-1, respectively. The accuracy of the method was confirmed using recovery experiments as well as CE-UV-VIS and HPLC-UV-VIS techniques. The developed method allows unambiguous identification of amino acids in native form without chemical derivatization and with the possibility of simultaneous analysis of amino acids with metal cations.

Dietary supplementation with ellagic acid improves the growth performance, meat quality, and metabolomics profile of yellow-feathered broiler chickens

The aim of this research was to explore the effects of ellagic acid (EA) on growth performance, meat quality, and metabolomics profile of broiler chickens. 240 healthy yellow-feathered broilers were randomly divided into 4 groups (6 replicates/group and 10 broilers /replicate): 1) a standard diet (CON); 2) CON+0.01% EA; 3) CON+0.02% EA; 4) CON+0.04% EA. Compared with the CON group, dietary 0.02% EA increased linearly and quadratically the ADG and lowered F/G ratio from 29 to 56 d and from 1 to 56 d of age (P < 0.05). The EA groups had higher spleen index and showed linear and quadratic improve thymus index (P < 0.05). A total of 0.02% EA linearly and quadratically increased the leg muscle percentage and quadratically increased the breast muscle percentage (P < 0.05). Compared to the control diet, 0.02% EA decreased quadratically the L* and increased a* of breast muscle at 45 min postslaughter (P < 0.05), and quadratically decreased (P < 0.05) the b* and increased linearly and quadratically (P < 0.05) drip loss. Additionally, EA improved linearly and quadratically (P < 0.05) serum total protein concentration and reduced linearly and quadratically (P < 0.05) serum blood urea nitrogen concentration. A total of 0.02% EA quadratically increased catalase activity and decreased malondialdehyde concentration in breast muscle compared with the control diet (P < 0.05). 0.02% and 0.04% EA could linearly and quadratically increase (P < 0.05) the concentrations of histidine, leucine and essential amino acids (EAA), 0.02% EA could linearly and quadratically increase (P < 0.05) the concentrations of threonine, glutamate, and flavored amino acids in breast muscle. 0.02% EA linearly and quadratically improved the C20:3n6, C22:6n3, polyunsaturated fatty acid (PUFA) concentrations, and the ratio of PUFA to saturated fatty acids (SFA), but reduced the C16:0 and the SFA concentrations in breast muscle than the CON group (P < 0.05). The EA diet linearly increased (P = 0.035) and quadratically tended (P = 0.068) to regulate the C18:2n6c concentration of breast muscle. Metabolomics showed that alanine metabolism, aspartate and glutamate metabolism, arginine and proline metabolism, taurine and hypotaurine metabolism, and glycerophospholipid metabolism were the most differentially abundant. These results showed that EA supported moderate positive effects on growth performance, meat quality, and metabolomics profile of broilers.

Construction of a co-expression network affecting intramuscular fat content and meat color redness based on transcriptome analysis

Introduction: Intramuscular fat content (IFC) and meat color are vital indicators of pork quality. Methods: A significant positive correlation between IFC and redness of meat color (CIE a* value) indicates that these two traits are likely to be regulated by shared molecular pathways.To identify candidate genes, hub genes, and signaling pathways that regulate these two traits, we measured the IFC and CIE a* value in 147 hybrid pigs, and selected individuls with extreme phenotypes for transcriptome analysis. Results: The results revealed 485 and 394 overlapping differentially expressed genes (DEGs), using the DESeq2, limma, and edgeR packages, affecting the IFC and CIE a* value, respectively. Weighted gene co-expression network analysis (WGCNA) identified four modules significantly correlated with the IFC and CIE a* value. Moreover, we integrated functional enrichment analysis results based on DEGs, GSEA, and WGCNA conditions to identify candidate genes, and identified 47 and 53 candidate genes affecting the IFC and CIE a* value, respectively. The protein protein interaction (PPI) network analysis of candidate genes showed that 5 and 13 hub genes affect the IFC and CIE a* value, respectively. These genes mainly participate in various pathways related to lipid metabolism and redox reactions. Notably, four crucial hub genes (MYC, SOX9, CEBPB, and PPAGRC1A) were shared for these two traits. Discussion and conclusion: After functional annotation of these four hub genes, we hypothesized that the SOX9/CEBPB/PPARGC1A axis could co-regulate lipid metabolism and the myoglobin redox response. Further research on these hub genes, especially the SOX9/CEBPB/PPARGC1A axis, will help to understand the molecular mechanism of the co-regulation of the IFC and CIE a* value, which will provide a theoretical basis for improving pork quality.

Effects of dietary Clostridium butyricum and rumen protected fat on meat quality, oxidative stability, and chemical composition of finishing goats

BACKGROUND

Clostridium butyricum (CB) is a probiotic that can regulate intestinal microbial composition and improve meat quality. Rumen protected fat (RPF) has been shown to increase the dietary energy density and provide essential fatty acids. However, it is still unknown whether dietary supplementation with CB and RPF exerts beneficial effects on growth performance and nutritional value of goat meat. This study aimed to investigate the effects of dietary CB and RPF supplementation on growth performance, meat quality, oxidative stability, and meat nutritional value of finishing goats. Thirty-two goats (initial body weight, 20.5 ± 0.82 kg) were used in a completely randomized block design with a 2 RPF supplementation (0 vs. 30 g/d) × 2 CB supplementation (0 vs. 1.0 g/d) factorial treatment arrangement. The experiment included a 14-d adaptation and 70-d data and sample collection period. The goats were fed a diet consisted of 400 g/kg peanut seedling and 600 g/kg corn-based concentrate (dry matter basis).

RESULT

Interaction between CB and RPF was rarely observed on the variables measured, except that shear force was reduced (P < 0.05) by adding CB or RPF alone or their combination; the increased intramuscular fat (IMF) content with adding RPF was more pronounced (P < 0.05) with CB than without CB addition. The pH24h (P = 0.009), a* values (P = 0.007), total antioxidant capacity (P = 0.050), glutathione peroxidase activities (P = 0.006), concentrations of 18:3 (P < 0.001), 20:5 (P = 0.003) and total polyunsaturated fatty acids (P = 0.048) were increased, whereas the L* values (P < 0.001), shear force (P = 0.050) and malondialdehyde content (P = 0.044) were decreased by adding CB. Furthermore, CB supplementation increased essential amino acid (P = 0.027), flavor amino acid (P = 0.010) and total amino acid contents (P = 0.024) as well as upregulated the expression of lipoprotein lipase (P = 0.034) and peroxisome proliferator-activated receptor γ (PPARγ) (P = 0.012), and downregulated the expression of stearoyl-CoA desaturase (SCD) (P = 0.034). The RPF supplementation increased dry matter intake (P = 0.005), averaged daily gain (trend, P = 0.058), hot carcass weight (P = 0.046), backfat thickness (P = 0.006), concentrations of 16:0 (P < 0.001) and c9-18:1 (P = 0.002), and decreased the shear force (P < 0.001), isoleucine (P = 0.049) and lysine content (P = 0.003) of meat. In addition, the expressions of acetyl-CoA carboxylase (P = 0.003), fatty acid synthase (P = 0.038), SCD (P < 0.001) and PPARγ (P = 0.022) were upregulated due to RPF supplementation, resulting in higher (P < 0.001) content of IMF.

CONCLUSIONS

CB and RPF could be fed to goats for improving the growth performance, carcass traits and meat quality, and promote fat deposition by upregulating the expression of lipogenic genes of Longissimus thoracis muscle.

The Effects of Composite Alkali-Stored Spent Hypsizygus marmoreus Substrate on Carcass Quality, Rumen Fermentation, and Rumen Microbial Diversity in Goats

The objective of this study was to investigate the effects of composite alkali-stored spent Hypsizygus marmoreus substrate (SHMS) on carcass quality, rumen fermentation, and rumen microbial diversity in goats. Twenty-four 6-month-old Chuanzhong black goats with similar body weights (20 ± 5 kg) were selected and randomly divided into four groups (n = 6 per group) and received four treatments: 0% (control group, CG); 20% (low-addition group, LG); 30% (moderate-addition group, MG); and 40% (high-addition group, HG) of SHMS-replaced silage corn and oat hay. The experiment lasted for 74 days (including a 14 d adaptation period and a 60 d treatment period). The results of this study showed that MG and HG significantly improved the marble score of goat meat (p < 0.05). The flesh color score significantly increased in each group (p < 0.05). The fat color scores significantly increased in LG and MG (p < 0.05). There were no significant effects on the pH value or shear force of the longissimus dorsi in each group (p > 0.05). The cooking loss in MG was higher than that in CG (p < 0.05). The histidine and tyrosine contents in each group of muscles significantly increased (p < 0.05), with no significant effect on fatty acids (p > 0.05). The rumen pH of MG significantly decreased (p < 0.05), while the total volatile fatty acids (TVFAs) and ammoniacal nitrogen (NH3-N) increased by 44.63% and 54.50%, respectively. The addition of the SHMS altered both the alpha and beta diversities of the rumen microbiota and significant differences in the composition and structure of the four microbial communities. The dominant bacterial phylum in each group were Firmicutes and Bacteroidetes, with Prevotella 1 as the dominant bacterial genus. Correlation analysis revealed that rumen bacteria are closely related to the animal carcass quality and rumen fermentation. In the PICRUSt prediction, 21 significantly different pathways were found, and the correlation network showed a positive correlation between the Prevotella 1 and 7 metabolic pathways, while the C5-branched dibasic acid metabolism was positively correlated with nine bacteria. In summary, feeding goats with an SHMS diet can improve the carcass quality, promote rumen fermentation, and alter the microbial structure. The research results can provide a scientific reference for the utilization of SHMS as feed in the goat industry.

Integrated Analysis of Transcriptome and Metabolome Profiles in the Longissimus Dorsi Muscle of Buffalo and Cattle

Buffalo meat is gaining popularity for its nutritional properties, such as its low fat and cholesterol content. However, it is often unsatisfactory to consumers due to its dark color and low tenderness. There is currently limited research on the regulatory mechanisms of buffalo meat quality. Xinglong buffalo are raised in the tropical Hainan region and are undergoing genetic improvement from draught to meat production. For the first time, we evaluated the meat quality traits of Xinglong buffalo using the longissimus dorsi muscle and compared them to Hainan cattle. Furthermore, we utilized a multi-omics approach combining transcriptomics and metabolomics to explore the underlying molecular mechanism regulating meat quality traits. We found that the Xinglong buffalo had significantly higher meat color redness but lower amino acid content and higher shear force compared to Hainan cattle. Differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) were identified, with them being significantly enriched in nicotinic acid and nicotinamide metabolic and glycine, serine, and threonine metabolic pathways. The correlation analysis revealed that those genes and metabolites (such as: GAMT, GCSH, PNP, L-aspartic acid, NADP+, and glutathione) are significantly associated with meat color, tenderness, and amino acid content, indicating their potential as candidate genes and biological indicators associated with meat quality. This study contributes to the breed genetic improvement and enhancement of buffalo meat quality.

Effects of lactic acid bacteria-derived fermented feed on the taste and quality of duck meat

The present study aimed to examine the impact of lactic acid bacteria- fermented feed (FF) on the taste and quality of duck meat, in addition to elucidating the potential metabolomic mechanism at play. The findings revealed that ducks fed with FF exhibited elevated pH levels and reduced cooking loss in their meat when compared to the control group. In addition, the sensory evaluation and e-tongue analysis revealed that the tenderness, juiciness, umami, richness, saltiness, and sweetness of duck meat were all enhanced by feeding FF. Moreover, an examination of the metabolome using 1H nuclear magnetic resonance (1H NMR) identified the principal differential metabolites that exhibited a correlation with taste, which included 2-aminoadipate, glucose, glycine, N-acetylcysteine, niacinamide, proline, and threonine. Furthermore, the differential metabolites that exhibited the greatest enrichment in duck meat could be primarily traced to glutathione metabolism, glycine, serine and threonine metabolism, taurine and hypotaurine metabolism. The potential factors contributing to the effect of FF and basic commercial duck feed (CF) were found to be primarily regulated via the aforementioned metabolic pathways. The study, therefore, offers a viable approach for enhancing the taste and quality of duck meat.

Biogenic Selenium Nanoparticles Synthesized Using Alginate Oligosaccharides Attenuate Heat Stress-Induced Impairment of Breast Meat Quality via Regulating Oxidative Stress, Metabolome and Ferroptosis in Broilers

Selenium (Se) is an indispensable trace element with versatile functions in antioxidant defense in poultry. In our previous study, we synthesized a novel type of biogenic selenium nanoparticle based on alginate oligosaccharides (SeNPs-AOS), and found that the particles are sized around 80 nm with an 8% Se content, and the dietary addition of 5 mg/kg of SeNPs-AOS could effectively alleviate the deleterious effects of heat stress (HS) in broilers, but it is still unclear whether SeNPs-AOS can improve the meat quality. Therefore, the aim of this study was to evaluate the protective effects of SeNPs-AOS on breast meat quality in heat-stressed broilers, and explore the relevant mechanisms. Birds at the age of 21 days were randomly divided into four groups with six replicates per group (eight broilers per replicate) according to a 2 × 2 experimental design, using HS (33 ± 2 °C, 10 h/day vs. thermoneutral, TN, under 23 ± 1.5 °C) and SeNPs-AOS (5 mg/kg feed vs. no inclusion) as variables. The results showed that dietary SeNPs-AOS decreased the cooking loss (p < 0.05), freezing loss (p < 0.001), and shear force (p < 0.01) of breast muscle in heat-stressed broilers. The non-targeted metabolomics analysis of the breast muscle identified 78 differential metabolites between the HS and HS + SeNPs-AOS groups, mainly enriched in the arginine and proline metabolism, β-alanine metabolism, D-arginine and D-ornithine metabolism, pantothenate, and CoA biosynthesis pathways (p < 0.05). Meanwhile, supplementation with SeNPs-AOS increased the levels of the total antioxidant capacity (T-AOC), the activities of catalase (CAT) and glutathione peroxidase (GSH-Px), and decreased the content of malondialdehyde (MDA) in the breast muscle (p < 0.05) in broilers under HS exposure. Additionally, SeNPs-AOS upregulated the mRNA expression of CAT, GPX1, GPX3, heme oxygenase-1 (HO-1), masculoaponeurotic fibrosarcoma G (MafG), MafK, selenoprotein W (SELENOW), SELENOK, ferritin heavy polypeptide-1 (FTH1), Ferroportin 1 (Fpn1), and nuclear factor erythroid 2-related factor 2 (Nrf2) (p < 0.05), while it downregulated Kelch-like ECH-associated pro-36 tein 1 (Keap1) and prostaglandin-endoperoxide Synthase 2 (PTGS2) expression (p < 0.05) in broilers under HS. These findings demonstrated that the dietary addition of SeNPs-AOS mitigated HS-induced oxidative damage and metabolite changes in the breast muscle of broilers, which may be related to the regulation of the Nrf2 signaling pathway and selenoprotein synthesis. In addition, SeNPs-AOS upregulated the breast muscle gene expression of anti-ferroptosis-related molecules in broilers under HS, suggesting that SeNPs-AOS can be used as novel Se supplements against HS in broilers.