Dietary Supplementation With Chlorogenic Acid Derived From Lonicera macranthoides Hand-Mazz Improves Meat Quality and Muscle Fiber Characteristics of Finishing Pigs via Enhancement of Antioxidant Capacity

Docosahexaenoic acid-enriched diet improves the flesh quality of freshwater fish (Megalobrama amblycephala): Evaluation based on nutritional value, texture and flavor

Docosahexaenoic acid (DHA) is a potential regulatory substance for flesh quality of fish, while the related evaluation is still barely. In this study, the effects of DHA-enriched diets on the flesh quality of freshwater fish (Megalobrama amblycephala) were investigated systematically. The sub-adult M. amblycephala were randomly fed with control diet (CON), 0.2% DHA diet (DL) or 0.8% DHA diet (DH). After 12-week feeding trial, the DH group flesh had higher concentrations of essential amino acids and polyunsaturated fatty acids compared to the CON group. Meanwhile, the hardness, springiness, shear force and moisture-holding capacity, as well as the values of umami, richness and sweetness were also improved by DH. The non-targeted metabolomics analysis revealed the key metabolites that may have significantly positive influence on flavor. Collectively, the diet supplementation with 0.8% DHA could achieve the improvement of the flesh quality in terms of nutritional value, texture and flavor in freshwater fish.

Tuna Dark Muscle Feeding Improved the Meat Quality of Holland Mini-Piglets and Modulated the Gut Microbiota

Pork is one of the most widely produced and consumed meats in the world, and it is also an important source of animal protein. The continuous rise in feed prices has forced the pig industry to consider adding cost-effective alternative feed to pig diets. In this study, we aimed to explore the beneficial effects of tuna dark muscle as a nutritional supplement on the growth performance, serum lipids and antioxidant levels of Holland mini-piglets, as well as on the odor and volatile substances of pork and the gut microbiota. Two-month-old male mini-piglets (n = 24) were fed a control diet or supplemented with either 2% (LD) or 4% (HD) tuna dark muscle for 8 weeks. The use of tuna dark muscle at low and high dosages significantly increased the average daily weight gain, but it showed no significant effect on organ indices or blood lipids. In addition, dark muscle treatment significantly increased the antioxidant capacity, characterized by increased SOD and GSH-Px activities, and it decreased the content of MDA in serum. Moreover, tuna dark muscle feeding shifted the odor of rib muscle and tendon meat away from that of the control group, while similar odor patterns were observed in the longissimus dorsi muscle. Among these volatile substances, hexanal, nonanal, and heptanal increased in response to dietary tuna dark muscle and were regarded as indispensable contributors to the feeding. Furthermore, dietary tuna dark muscle modulated the gut microbiota of the piglets, increasing the abundance of beneficial bacteria such as butyric acid-producing bacteria, and reduced the abundance of harmful bacteria. The feeding strategy reported in this study not only reduces the production costs of pork but also utilizes tuna processing by-products in an environmentally friendly way.

Quantitative Phosphoproteomics Analysis Reveals the Protective Mechanism of Chlorogenic Acid on Immunologically Stressed Broiler Meat Quality

Modern poultry production is stressful for the birds, and this stress is recognized as a major cause of inferior meat quality. Chlorogenic acid (CGA), a plant phenolic acid, has excellent antioxidant and anti-inflammatory properties. The antioxidant capacity and phosphoproteomics of immunologically stressed broiler breast muscle were assessed to elucidate the mechanism of the beneficial effects of CGA on meat quality. Dietary CGA decreased drip and cooking loss, postmortem pH and antioxidant capacity of breast muscle from stressed broilers, and increased MyHC-I mRNA levels. Quantitative phosphoproteomics revealed that CGA supplementation downregulated the phosphorylation of myofibrillar proteins, glycolytic enzymes, and endoplasmic reticulum proteins involved in homeostasis, which contributed to improving the meat quality of broilers. Moreover, 14 phosphorylation sites (e.g., P13538-Ser1236 and F1NN63-Ser117) in 13 phosphoproteins were identified as key regulators of processes related to broiler meat quality. Together, these findings provide novel regulatory targets and nutritional strategies for improving the stressed broiler meat quality.

Bioactive functions of chlorogenic acid and its research progress in pig industry

Chlorogenic acid (CGA), also known as 3-caffeioylquinic acid or coffee tannin, is a water-soluble polyphenol phenylacrylate compound produced through the shikimate pathway by plants during aerobic respiration. CGA widely exists in higher dicotyledons, ferns and many Chinese medicinal materials, and enjoys the reputation of 'plant gold'. Here, we summarized the source, chemical structure, biological activity functions of CGA and its research progress in pigs, aiming to provide a more comprehensive understanding and theoretical basis for the prospect of CGA replacing antibiotics as a pig feed additive.

Effects of Dietary Chlorogenic Acid Supplementation on Growth Performance, Meat Quality, and Muscle Flavor Substances in Finishing Pigs

With the prohibition of antibiotics in feed, certain phytocompounds have been widely studied as feed additives. Chlorogenic acid (CGA), a natural polyphenol found in plants, possesses anti-inflammatory, antioxidant, and metabolic regulatory features. The objective of this study was to investigate the effects of dietary chlorogenic acid supplementation on growth performance and carcass traits, as well as meat quality, nutrient value and flavor substances of Duroc × Landrace × Yorkshire (DLY) pigs. Forty healthy DLY pigs (initial body weight (BW): 26.69 ± 0.37) were allotted to four treatment groups and were fed with the control diet, which was supplemented with 25 mg kg-1, 50 mg kg-1, and 100 mg kg-1 CGA, respectively. The trial lasted 100 days. The results suggested that dietary CGA supplementation had no effect (p < 0.05) on the average daily gain (ADG) and feed conversion ratio (FC). Herein, it was found that 50 mg kg-1 CGA-containing diet not only increased the dressing percentage and perirenal fat, but also reduced the rate of muscular pH decline (p < 0.05). In the longissimus thoracis (LT) muscle, the myofiber-type-related genes such as the MyHC IIa and MyHC IIX mRNA levels were increased by 100 mg kg-1 CGA. The results also indicated that the 100 mg kg-1 CGA-containing diet increased the content of crude fat, glycogen, total amino acids, and flavor amino acids, but decreased the inosine and hypoxanthine concentration in LT (p < 0.05). Meanwhile, the lipogenic gene ACC1 mRNA level was elevated by 50 mg kg-1 CGA. Instead, 100 mg kg-1 CGA downregulated the expression level of NT5C2, an enzyme responsible for inosine-5'-monophosphate (IMP) degradation. Additionally, 100 mg kg-1 CGA decreased the malondialdehyde (MDA) content, but increased the glutathione peroxidase (GSH-Px) content as well as antioxidant gene (HO-1, NQO-1, NRF2) mRNA levels in LT muscle. These findings showed that dietary CGA could partly improve carcass traits and muscle flavor without negatively affecting growth performance, and the underlying mechanism may be due to the antioxidant properties induced by CGA.

Productive Performance, Physiological Variables, and Carcass Quality of Finishing Pigs Supplemented with Ferulic Acid and Grape Pomace under Heat Stress Conditions

The effect of individual and combined supplementation of FA and GPM on physiological variables, productive performance, and carcass characteristics of finishing pigs under heat stress conditions were investigated. Forty Yorkshire × Duroc pigs (80.23 kg) were individually housed and randomly distributed into 4 groups under a 2 × 2 factorial arrangement (n = 10): Control (basal diet, BD); FA, BD + 25 mg FA; GPM, BD with 2.5% GPM; and MIX, BD with 25 mg FA and 2.5% GPM. Additives were supplemented for 31 days. The inclusion of FA or GPM did not modify rectal temperature and respiratory rate. There was an effect of the interaction on FI, which increased when only GPM was supplemented, with respect to Control and MIX (p < 0.05). Average daily gain (ADG) and feed conversion (FC) were not affected by treatments (p > 0.05). The inclusion of FA improved hot and cold carcass weight, while the addition of GPM decreased the marbling (p < 0.05) and tended to increase loin area (p < 0.10). GPM increased liver weight (p < 0.05). The addition of GPM and FA can improve some carcass characteristics under heat stress conditions. It is necessary to continue investigating different levels of inclusion of GPM and FA in finishing pigs' diets.

Bioactivity of Wild and Cultivated Legumes: Phytochemical Content and Antioxidant Properties

The global demand for increased meat production has brought to the surface several obstacles concerning environmental impacts, animals’ welfare, and quality features, revealing the need to produce safe foodstuffs with an environmentally acceptable procedure. In this regard, the incorporation of legumes into animal diets constitutes a sustainable way out that prevents these apprehensions. Legumes are plant crops belonging to the Fabaceae family and are known for their rich content of secondary metabolites., displaying significant antioxidant properties and a series of health and environmental benefits. The study herein aims to investigate the chemical composition and antioxidant activities of indigenous and cultivated legume plants used for food and feed. The respective results indicate that the methanolic extract of Lathyrus laxiflorus (Desf.) Kuntze displayed the highest phenolic (64.8 mg gallic acid equivalents/g extract) and tannin (419.6 mg catechin equivalents/g extract) content, while the dichloromethane extract of Astragalus glycyphyllos L., Trifolium physodes Steven ex M.Bieb. and Bituminaria bituminosa (L.) C.H.Stirt. plant samples exhibited the richest content in carotenoids lutein (0.0431 mg/g A. glycyphyllos extract and 0.0546 mg/g B. bituminosa extract), α-carotene (0.0431 mg/g T. physodes extract) and β-carotene (0.090 mg/g T. physodes extract and 0.3705 mg/g B. bituminosa extract) establishing their potential role as vitamin A precursor sources. Results presented herein verify the great potential of Fabaceae family plants for utilization as pasture plants and/or dietary ingredients, since their cultivation has a positive impact on the environment, and they were found to contain essential nutrients capable to improve health, welfare, and safety.

The Effects of Dietary Inclusion of Mulberry Leaf Powder on Growth Performance, Carcass Traits and Meat Quality of Tibetan Pigs

This research was conducted to study the effects of dietary inclusion of mulberry leaf powder (MLP) on growth performance, meat quality, antioxidant activity, and carcass traits of Tibetan pigs. Eighteen Tibetan pigs (33.8 ± 1.1 kg) were assigned to two treatment groups randomly and received either the control diet (CON) or a basal diet containing 8% MLP (MLP) for two months. After the two-month feeding trial, the MLP group showed lower backfat thickness while a higher lean percentage. Compared with CON pigs, MLP pigs had higher serum CAT activity. In addition, dietary MLP supplementation significantly decreased the muscle shear force. Muscle fiber morphology analysis showed that MLP pigs had larger muscle fiber density while smaller muscle fiber cross-sectional area. Up-regulated gene expression of myosin heavy chain (MyHC)IIa was also observed in MLP pigs. These results indicate that the enhanced antioxidant activity and altered muscle fiber type and morphology appeared to contribute to the improvement of meat quality in Tibetan pigs fed diets containing MLP.

Fe(III) and Cu(II) Complexes of Chlorogenic Acid: Spectroscopic, Thermal, Anti-/Pro-Oxidant, and Cytotoxic Studies

Complexes of chlorogenic acid (5-CQA) with copper(II) and iron(III) were synthesized in a solid state and examined by means of FT-IR, thermogravimetric, and elemental analyses. The molar stoichiometric ratios of metal:ligand for the solid forms of the complexes were established as Cu(II):L = 1:2 and Fe(III):L = 2:3 (L: 5-CQA), with the possible coordination through the carboxylate group and the hydroxyl group from the catechol moiety. In an aqueous solution at pH = 7.4, the composition of the complexes was Cu(II):L = 1:1, and Fe(III):L = 1:1 and 1:2. The Cu(II) and Fe(III) complexes with 5-CQA showed lower antioxidant properties, as estimated by the spectrophotometric methods with DPPH^•, ABTS^•+, and HO^• radicals, than the ligand alone, whereas in the lipid peroxidation inhibition assay, the metal complexes revealed a higher antioxidant activity than 5-CQA. Cu(II) 5-CQA showed the highest pro-oxidant activity in the Trolox oxidation assays compared to the other studied compounds. The lipophilic parameters of the compounds were estimated using the HPLC method. 5-CQA and its complexes with Fe(III) and Cu(II) were not toxic to HaCaT cells in a tested concentration range of 0.15-1000 nM after a 24 h incubation time.

Molecular Characterization of LKB1 of Triploid Crucian Carp and Its Regulation on Muscle Growth and Quality

Liver Kinase B1 (LKB1) is a serine/threonine kinase that can regulate energy metabolism and skeletal muscle growth. In the present study, LKB1 cDNA of triploid crucian carp (Carassius auratus) was cloned. The cDNA contains a complete open reading frame (ORF), with a length of 1326 bp, encoding 442 amino acids. Phylogenetic tree analysis showed that the LKB1 amino acid sequence of the triploid crucian carp had a high sequence similarity and identity with carp (Cyprinus carpio). Tissue expression analysis revealed that LKB1 was widely expressed in various tissues. LKB1 expressions in the brain were highest, followed by kidney and muscle. In the short-term LKB1 activator and inhibitor injection experiment, when LKB1 was activated for 72 h, expressions of myogenic differentiation (MyoD), muscle regulatory factor (MRF4), myogenic factor (MyoG) and myostatin 1 (MSTN1) were markedly elevated and the content of inosine monophosphate (IMP) in muscle was significantly increased. When LKB1 was inhibited for 72 h, expressions of MyoD, MyoG, MRF4 and MSTN1 were markedly decreased. The long-term injection experiment of the LKB1 activator revealed that, when LKB1 was activated for 15 days, its muscle fibers were significantly larger and tighter than the control group. In texture profile analysis, it showed smaller hardness and adhesion, greater elasticity and chewiness. Contrastingly, when LKB1 was inhibited for 9 days, its muscle fibers were significantly smaller, while the gap between muscle fibers was significantly larger. Texture profile analysis showed that adhesion was significantly higher than the control group. A feeding trial on triploid crucian carp showed that with dietary lysine-glutamate dipeptide concentration increasing, the expression of the LKB1 gene gradually increased and was highest when dipeptide concentration was 1.6%. These findings may provide new insights into the effects of LKB1 on fish skeletal muscle growth and muscle quality, and will provide a potential application value in improvement of aquaculture feed formula.

Dietary stevia residue extract supplementation improves the performance and antioxidative capacity of growing-finishing pigs

BACKGROUND

Improper disposal of stevia residue causes environmental pollution and waste of resources. The extract of stevia residue is rich in chlorogenic acid and isochlorogenic acids, and has a great potential in livestock and poultry breeding. Therefore, this study aimed to investigate the effects of dietary stevia residue extract (SRE) supplementation on the performance, meat quality, antioxidative capacity and gut microbiota in growing-finishing pigs.

RESULTS

The results showed that increasing the concentration of SRE supplementation linearly increased (P < 0.05) body weight from day 1 to 35. Supplementation with SRE significantly increased (P < 0.05) average daily gain (ADG) from day 1 to 75. 100 mg kg-1 SRE supplementation significantly increased (P < 0.05) hot carcass weight and gastric index. Moreover, increasing the concentration of SRE linearly increased (P < 0.05) the score of appearance of longissimus thoracis, as well as serum albumin, triglyceride and high-density lipoprotein cholesterol content. Further study found that increasing the concentration of SRE linearly increased (P < 0.05) serum total superoxide dismutase activity, and showed a significant quadratic relationship (P < 0.05) with activity of serum catalase, while linearly decreasing (P < 0.05) muscle malondialdehyde (MDA) content. Furthermore, supplementation with 100 mg kg-1 SRE significantly decreased (P < 0.05) serum MDA content, while 600 and 800 mg kg-1 SRE supplementation significantly decreased (P < 0.05) muscle MDA content. However, SRE supplementation had no significant effect on gut microbiota (P > 0.05).

CONCLUSION

These data indicated that dietary SRE supplementation improves the performance and antioxidative capacity of growing-finishing pigs. We recommend that the optimal supplemental level of SRE in the diet of growing-finishing pigs is 100 mg kg-1 . © 2022 Society of Chemical Industry.

The Effect of Dietary Leucine Supplementation on Antioxidant Capacity and Meat Quality of Finishing Pigs under Heat Stress

This study examined the effects of dietary leucine supplements on antioxidant capacity and meat quality in growing-finishing pigs. A total of 24 crossbred (Duroc × Landrace × Yorkshire) pigs with an average initial weight of 68.33 ± 0.97 kg were randomly allotted to three treatment groups. All pigs were exposed to constant heat stress. Each group of pigs was fed a basal diet, or a diet supplemented with increasing levels of leucine (0.25% or 0.50%). The results showed that leucine intake could improve average daily gain and reduce feed/gain of finishing pigs under heat stress (p < 0.05). The supplementation of leucine could improve the carcass slant length (p = 0.09), and dramatically increased loin-eye area of the finishing pigs (p < 0.05) but had no significant effect on other carcass traits. Compared with the control group, 0.50% leucine markedly reduced drip loss and shear force of longissimus dorsi muscle, and increased pH value at 24 h after slaughter (p < 0.05). Dietary supplementation of 0.25% leucine increased the contents of inosine monophosphate and intramuscular fat in biceps femoris muscle (p < 0.05). Supplementation of 0.25% or 0.50% leucine significantly stimulated the activities of antioxidant enzymes while reduced the level of MDA in serum, liver and longissimus dorsi muscle (p < 0.05). Compared with the control group, 0.50% leucine supplementation markedly modulated the relative mRNA expression levels of genes related to muscle fiber type and mitochondrial function in longissimus dorsi muscle and the gene relative antioxidant in the liver (p < 0.05). In conclusion, dietary leucine supplementation could improve the growth performance and meat quality of the finishing pigs under heat stress, and the pathway of Keap1-NRF2 and PGC-1α-TFAM might be involved.

Effects of Dietary Chlorogenic Acid Supplementation Derived from Lonicera macranthoides Hand-Mazz on Growth Performance, Free Amino Acid Profile, and Muscle Protein Synthesis in a Finishing Pig Model

Chlorogenic acid (CGA), as one of the richest polyphenol compounds in nature, has broad applications in many fields due to its various biological properties. However, initial data on the effects of dietary CGA on protein synthesis and related basal metabolic activity has rarely been reported. The current study is aimed at (1) determining whether dietary CGA supplementation improves the growth performance and carcass traits, (2) assessing whether dietary CGA alters the free amino acid profile, and (3) verifying whether dietary CGA promotes muscle protein synthesis in finishing pigs. Thirty-two (Large × White × Landrace) finishing barrows with an average initial body weight of $71.89\pm 0.92$  kg were randomly allotted to 4 groups and fed diets supplemented with 0, 0.02%, 0.04%, and 0.08% CGA, respectively. The results indicated that, compared with the control group, dietary supplementation with 0.04% CGA slightly stimulated the growth performance of pigs, whereas no significant correlation was noted between the dietary CGA levels and animal growth ( $P>0.05$ ). Furthermore, the carcass traits of pigs were improved by 0.04% dietary CGA ( $P<0.01$ ). In addition, dietary CGA significantly improved the serum free amino acid profiles of pigs ( $P<0.01$ ), while 0.04% dietary CGA promoted more amino acids to translocate to skeletal muscles ( $P<0.05$ ). The relative mRNA expression levels of SNAT2 in both longissimus dorsi (LD) and biceps femoris (BF) muscles were augmented in the 0.02% and 0.04% groups ( $P<0.05$ ), and the LAT1 mRNA expression in the BF muscle was elevated in the 0.02% group ( $P<0.05$ ). We also found that dietary CGA supplementation at the levels of 0.04% or 0.08% promoted the expression of p-Akt and activated the mTOR-S6K1-4EBP1 axis in the LD muscle ( $P<0.05$ ). Besides, the MAFbx mRNA abundance in the 0.02% and 0.04% groups was significantly lower ( $P<0.05$ ). Our results revealed that dietary supplementation with CGA of 0.04% improved the free amino acid profile and enhanced muscle protein biosynthesis in the LD muscle in finishing pigs.

Protective effects of chlorogenic acid on the meat quality of oxidatively stressed broilers revealed by integrated metabolomics and antioxidant analysis

Oxidation is a major cause of meat quality deterioration during broiler production, which leads to undesirable meat color and impaired water holding capacity (WHC), thereby impacting consumer appeal and satisfaction. Chlorogenic acid (CGA), a natural phenolic acid, is regarded as a potential, safer and healthier antioxidant to improve meat quality. To investigate the protective effects of CGA on the meat quality of oxidatively stressed broilers, 240 one-day-old male Cobb broiler chickens were allocated to four treatments: basal diet (control group), basal diet + dexamethasone (DEX) injection (DEX group), basal diet containing 500 mg kg^-1 CGA (CGA group), and basal diet containing 500 mg kg^-1 CGA + DEX injection (DEX_CGA group). Meat quality, antioxidant capacity, the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, and metabolomic profile were detected in the breast muscle of broilers. Then, correlation analysis between meat quality and antioxidant capacity, antioxidant-related genes, and metabolites was performed. The results indicated that CGA supplementation improved the growth performance and meat quality traits (pH, WHC, and meat color) and enhanced the antioxidant enzyme activity by activating the Nrf2 pathway in the breast muscle of oxidatively stressed broilers. A total of 619 metabolites were identified, among which 93 differential metabolites were found between control and DEX groups, and 65 differential metabolites were observed between DEX and DEX_CGA groups. Breast metabolic profiles were changed by DEX treatment, while CGA supplementation could normalize the metabolic changes in DEX-challenged broilers. Metabolic pathway analysis revealed that most of the differential metabolites between DEX and DEX_CGA groups were involved in pyrimidine/purine, propanoate and phenylalanine metabolism, primary bile acid biosynthesis, and lysine metabolism, which may contribute to explain the protective effects of CGA on meat quality. Moreover, according to the correlation analysis, four metabolites were identified as potential biomarkers to predict the meat quality. In conclusion, our findings demonstrate that CGA is an effective, natural and safe antioxidant to enhance the quality of meat from intensive industrial poultry production.