Mixed organic acids as an alternative to antibiotics improve serum biochemical parameters and intestinal health of weaned piglets

Knowledge graph-derived feed efficiency analysis via pig gut microbiota

Feed efficiency (FE) is essential for pig production, has been reported to be partially explained by gut microbiota. Despite an extensive body of research literature to this topic, studies regarding the regulation of feed efficiency by gut microbiota remain fragmented and mostly confined to disorganized or semi-structured unrestricted texts. Meanwhile, structured databases for microbiota analysis are available, yet they often lack a comprehensive understanding of the associated biological processes. Therefore, we have devised an approach to construct a comprehensive knowledge graph by combining unstructured textual intelligence with structured database information and applied it to investigate the relationship between pig gut microbes and FE. Firstly, we created the pgmReading knowledge base and the domain ontology of pig gut microbiota by annotating, extracting, and integrating semantic information from 157 scientific publications. Secondly, we created the pgmPubtator by utilizing PubTator to expand the semantic information related to microbiota. Thirdly, we created the pgmDatabase by mapping and combining the ADDAGMA, gutMGene, and KEGG databases based on the ontology. These three knowledge bases were integrated to form the Pig Gut Microbial Knowledge Graph (PGMKG). Additionally, we created five biological query cases to validate the performance of PGMKG. These cases not only allow us to identify microbes with the most significant impact on FE but also provide insights into the metabolites produced by these microbes and the associated metabolic pathways. This study introduces PGMKG, mapping key microbes in pig feed efficiency and guiding microbiota-targeted optimization.

Nutrition strategies to control post-weaning diarrhea of piglets: From the perspective of feeds

Post-weaning diarrhea (PWD) is a globally significant threat to the swine industry. Historically, antibiotics as well as high doses of zinc oxide and copper sulfate have been commonly used to control PWD. However, the development of bacterial resistance and environmental pollution have created an interest in alternative strategies. In recent years, the research surrounding these alternative strategies and the mechanisms of piglet diarrhea has been continually updated. Mechanically, diarrhea in piglets is a result of an imbalance in intestinal fluid and electrolyte absorption and secretion. In general, enterotoxigenic Escherichia coli (ETEC) and diarrheal viruses are known to cause an imbalance in the absorption and secretion of intestinal fluids and electrolytes in piglets, resulting in diarrhea when Cl- secretion-driven fluid secretion surpasses absorptive capacity. From a perspective of feedstuffs, factors that contribute to imbalances in fluid absorption and secretion in the intestines of weaned piglets include high levels of crude protein (CP), stimulation by certain antigenic proteins, high acid-binding capacity (ABC), and contamination with deoxynivalenol (DON) in the diet. In response, efforts to reduce CP levels in diets, select feedstuffs with lower ABC values, and process feedstuffs using physical, chemical, and biological approaches are important strategies for alleviating PWD in piglets. Additionally, the diet supplementation with additives such as vitamins and natural products can also play a role in reducing the diarrhea incidence in weaned piglets. Here, we examine the mechanisms of absorption and secretion of intestinal fluids and electrolytes in piglets, summarize nutritional strategies to control PWD in piglets from the perspective of feeds, and provide new insights towards future research directions.

Growth performance, serum parameters, inflammatory responses, intestinal morphology and microbiota of weaned piglets fed 18% crude protein diets with different ratios of standardized ileal digestible isoleucine to lysine

The present study was to explore the Ile requirement of piglets fed 18% crude protein (CP) diets. Two hundred and fifty 28-day-old Duroc × Landrace × Yorkshire piglets (8.37 ± 1.92 kg) were randomly divided into 5 dietary treatments (10 piglets per replicate, 5 barrows and 5 gilts per replicate) with 45%, 50%, 55%, 60%, 65% standardized ileal digestible (SID) Ile-to-Lys ratios, and the SID Lys was formulated to 1.19%. The experimental design consisted of two phases (d 1 to 14 and d 15 to 28). Results showed that average daily gain (ADG) had a tendency to quadratically increase as the SID Ile-to-Lys ratio increased (P = 0.09), and the optimum SID Ile-to-Lys ratios required to maximize ADG were 48.33% and 54.63% for broken-line linear model and quadratic polynomial model, respectively. Different SID Ile-to-Lys ratios had no significant effects on average daily feed intake and gain-to-feed ratio. Dry matter (P < 0.01), CP (P = 0.01), ether extract (P = 0.04), gross energy (P < 0.01) and organic matter (P < 0.01) digestibility increased quadratically. Serum total cholesterol levels decreased linearly (P = 0.01) and quadratically (P < 0.01); aspartate aminotransferase (P < 0.01), interleukin-1β (P = 0.01), and tumor necrosis factor-α (P < 0.01) levels decreased quadratically; immunoglobulin G (P = 0.03) and immunoglobulin M (P = 0.01) concentrations increased quadratically. Serum Ser levels decreased linearly (P < 0.01) and quadratically (P = 0.01); Glu (P = 0.02), Arg (P = 0.05), and Thr (P = 0.03) levels decreased quadratically; Gly (P < 0.01) and Leu (P = 0.01) levels decreased linearly; Ile (P < 0.01) concentration increased linearly. Duodenal villus height (P < 0.01) and villus height to crypt depth ratio (P < 0.01) increased quadratically. The deficiency or excess of Ile decreased short chain fatty acid-producing bacteria abundance and increased pathogenic bacteria abundance. Overall, taking ADG as the effect index, the optimum SID Ile-to-Lys ratios of piglets offered 18% CP diets were 48.33% and 54.63% based on two different statistical models, respectively, and the deficiency or excess of lle negatively affected piglet growth rates and health status.

Potential of Organic Acids, Essential Oils and Their Blends in Pig Diets as Alternatives to Antibiotic Growth Promoters

Over the years, the use of management and feeding strategies to enhance pig productivity while minimizing the use of antibiotic growth promoters has grown. Antibiotic growth promoters have been widely used as feed additives to reduce diet-related stress and improve pig performance. However, increasing concern about the consequences of long-term and increased use of antibiotic growth promoters in animal production has led to a paradigm shift towards the use of natural organic alternatives such as plant essential oils and organic acids in pig nutrition to enhance growth. Antibiotic growth promoters endanger human health by allowing multidrug-resistant genes to be transferred horizontally from non-pathogenic to pathogenic bacteria, as well as directly between animals and humans. Scientific research shows that alternative growth promoters such as essential oils and organic acids appear to improve pigs' ability to prevent pathogenic bacteria from colonizing the intestinal system, stabilizing the gut microflora and promoting eubiosis, as well as improving immunity and antioxidant stability. The purpose of this review was to provide an in-depth review of organic acids and essential oils as growth promoters in pig production, as well as their effects on productivity and meat quality. Organic acids and essential oils in pig diets are a safe way to improve pig performance and welfare while producing antibiotic-free pork.

A Mixture of Formic Acid, Benzoic Acid, and Essential Oils Enhanced Growth Performance via Modulating Nutrient Uptake, Mitochondrion Metabolism, and Immunomodulation in Weaned Piglets

This study aimed to evaluate the effects of a complex comprising formic acid, benzoic acid, and essential oils (AO3) on the growth performance of weaned piglets and explore the underlying mechanism. Dietary AO3 supplementation significantly enhanced the average daily gain (ADG) and average daily feed intake (ADFI), while decreasing the feed conversion rate (FCR) and diarrhea rate (p < 0.05). Additionally, AO3 addition altered the fecal microflora composition with increased abundance of f_Prevotellaceae. LPS challenges were further conducted to investigate the detailed mechanism underlying the benefits of AO3 supplementation. The piglets fed with AO3 exhibited a significant increase in villus height and decrease in crypt depth within the jejunum, along with upregulation of ZO-1, occludin, and claudin-1 (p < 0.05) compared with those piglets subjected to LPS. Furthermore, AO3 supplementation significantly ameliorated redox disturbances (T-AOC, SOD, and GSH) and inflammation (TNF-α, IL-1β, IL-6, and IL-12) in both the serum and jejunum of piglets induced by LPS, accompanied by suppressed activation of the MAPK signaling pathway (ERK, JNK, P38) and NF-κB. The LPS challenge downregulated the activation of the AMPK signaling pathway, mRNA levels of electron transport chain complexes, and key enzymes involved in ATP synthesis, which were significantly restored by the AO3 supplementation. Additionally, AO3 supplementation restored the reduced transport of amino acids, glucose, and fatty acids induced by LPS back to the levels observed in the control group. In conclusion, dietary AO3 supplementation positively affected growth performance and gut microbiota composition, also enhancing intestinal barrier integrity, nutrient uptake, and energy metabolism, as well as alleviating oxidative stress and inflammation under LPS stimulation.

Butyric acid glycerides as substitutes for antibiotics as growth enhancers in the diet of nursery piglets

This study aimed to determine whether the addition of butyric acid glycerides as substitutes to conventional growth promoters can provide adequate zootechnical performance and intestinal health in healthy piglets in the nursery phase. We used 90 male piglets (average weight of 6.5 kg) subdivided into five treatments with six replicates per treatment. The treatments had the same basal diet: NC-negative control (without growth promoter), PC-positive control (with gentamicin, oral), PSB-protected sodium butyrate, FSB-free sodium butyrate, and TRI-tributyrin. In these animals, zootechnical performance was evaluated on days 1, 10, 20 and 39, microbiological analysis on days 14 and 39, hematocrit, blood biochemistry and intestinal histology, intestinal oxidation and antioxidation on day 39. The average daily weight gain was higher in the TRI group on days 21 to 39 in the nursery (P = 0.03), with more significant weight gain from 1 to 39 days (P = 0.05). There were higher leukocyte counts in the PC group than in the TRI group and higher lymphocyte counts in the PC treatment than in the NC or TRI groups. Escherichia coli counts were lower in the PC, followed by the PSB and TRI groups on day 39 (P = 0.01). Lower crypt depths were found in the TRI and FSB groups, followed by PC, than in the NC group (P = 0.01). Higher values for crypt villosity ratio were found in the FSB and TRI groups than in the NC group (P = 0.05). Lower lipid peroxidation was found in analyzes of serum oxidative status (LPO: P = 0.01), associated with greater activities of superoxide dismutase - SOD (P = 0.08), glutathione S-transferase - GST (P = 0.09) in PSB and TRI groups than in the NC group. In conclusion, the use of butyric acid in the form of tributyrin can be used as growth enhancers in piglets in the nursery phase.

Citric Acid Promotes Immune Function by Modulating the Intestinal Barrier

Amidst increasing concern about antibiotic resistance resulting from the overuse of antibiotics, there is a growing interest in exploring alternative agents. One such agent is citric acid, an organic compound commonly used for various applications. Our research findings indicate that the inclusion of citric acid can have several beneficial effects on the tight junctions found in the mouse intestine. Firstly, the study suggests that citric acid may contribute to weight gain by stimulating the growth of intestinal epithelial cells (IE-6). Citric acid enhances the small intestinal villus-crypt ratio in mice, thereby promoting intestinal structural morphology. Additionally, citric acid has been found to increase the population of beneficial intestinal microorganisms, including Bifidobacterium and Lactobacillus. It also promotes the expression of important protein genes such as occludin, ZO-1, and claudin-1, which play crucial roles in maintaining the integrity of the tight junction barrier in the intestines. Furthermore, in infected IEC-6 cells with H9N2 avian influenza virus, citric acid augmented the expression of genes closely associated with the influenza virus infection. Moreover, it reduces the inflammatory response caused by the viral infection and thwarted influenza virus replication. These findings suggest that citric acid fortifies the intestinal tight junction barrier, inhibits the replication of influenza viruses targeting the intestinal tract, and boosts intestinal immune function.

A blend of formic acid, benzoic acid, and tributyrin alleviates ETEC K88-induced intestinal barrier dysfunction by regulating intestinal inflammation and gut microbiota in a murine model

This study aimed to investigate the effects of an organic acid (OA) blend on intestinal barrier function, intestinal inflammation, and gut microbiota in mice challenged with enterotoxigenic Escherichia coli K88 (ETEC K88). Ninety female Kunming mice (7 weeks old) were randomly allotted to five treatments with six replicates per treatment and three mice per replicate. The five treatments were composed of the non-ETEC K88 challenge group and ETEC K88 challenge + OA blend groups (0, 0.6 %, 1.2 %, and 2.4 % OA blend). The OA blend consisted of 47.5 % formic acid, 47.5 % benzoic acid, and 5 % tributyrin. The feeding trial lasted for 15 days, and mice were intraperitoneally injected with PBS or ETEC K88 solution on day 15. At 24 h post-challenge, one mouse per replicate was selected for sample collection. The results showed that a dosage of 0.6 % OA blend alleviated the ETEC K88-induced intestinal barrier dysfunction, as indicated by the elevated villus height and the ratio of villus height to crypt depth of jejunum, and the reduced serum diamine oxidase (DAO) and D-lactate levels, as well as the up-regulated mRNA levels of ZO-1, Claudin-1, and Occludin in jejunum mucosa of mice. Furthermore, dietary addition with 0.6 % OA blend decreased ETEC K88-induced inflammation response, as suggested by the decreased TNF-α and IL-6 levels, and the increased IgA level in the serum, as well as the down-regulated mRNA level of TNF-α, IL-6, IL-1β, TLR-4, MyD88, and MCP-1 in jejunum mucosa of mice. Regarding gut microbiota, the beta-diversity analysis revealed a remarkable clustering between the 0.6 % OA blend group and the ETEC K88 challenge group. Supplementation of 0.6 % OA blend decreased the relative abundance of Firmicutes, and increased the relative abundance of Bacteroidota, Desulfobacterota, and Verrucomicrobiota of colonic digesta in mice. Also, the butyric acid content in the colonic digesta of mice was increased by dietary 0.6 % OA blend supplementation. Collectively, a dosage of 0.6 % OA blend could alleviate the ETEC K88-induced intestinal barrier dysfunction by regulating intestinal inflammation and gut microbiota of mice.

Bioactive compounds, antibiotics and heavy metals: effects on the intestinal structure and microbiome of monogastric animals – a non-systematic review

The intestinal structure and gut microbiota are essential for the animals‘ health. Chemical components taken with food provide the right environment for a specific microbiome which, together with its metabolites and the products of digestion, create an environment, which in turn is affects the population size of specific bacteria. Disturbances in the composition of the gut microbiota can be a reason for the malformation of guts, which has a decisive impact on the animal‘ health. This review aimed to analyse scientific literature, published over the past 20 years, concerning the effect of nutritional factors on gut health, determined by the intestinal structure and microbiota of monogastric animals. Several topics have been investigated: bioactive compounds (probiotics, prebiotics, organic acids, and herbal active substances), antibiotics and heavy metals (essentaial minerals and toxic heavy metals).

Rhodotorula benthica culture as an alternative to antibiotics improves growth performance by improving nutrients digestibility and intestinal morphology, and modulating gut microbiota of weaned piglets

The effects of Rhodotorula benthica culture (RBC) and antibiotics (AB) on the growth performance, nutrients digestibility, morphological indicators, and colonic microbiota of weaning piglets were explored. Ninety-six (Duroc × Landrace × Large) weaned piglets (21-day-old) weighing 7.7 ± 0.83 kg, were randomly allocated to 4 dietary treatments. They were fed with basal diet (CON), basal diet + 25 mg/kg bacitracin zinc + 5 mg/kg colistin sulfate (AB), 5 g/kg reduction in soybean meal of basal diet + 5 g/kg RBC (RBC1), or 10 g/kg reduction in soybean meal of basal diet + 10 g/kg RBC (RBC2). The results showed that dietary RBC1 improved the body gain/feed intake (G/F) of weaned piglets than the CON diet, and the RBC2 diet improved the average daily gain and G/F than CON and AB diets from days 15 to 28 (P < 0.05). Supplementation of RBC2 improved the apparent total tract digestibility of dry matter, nitrogen, and gross energy in weaned piglets compared to controls from days 15 to 28 (P < 0.05). Dietary AB, RBC1, and RBC2 enhanced the ileal villus height (VH) and VH/crypt depth (CD), and these two indicators were greater in the RBC2-treated piglets than in the AB- and RBC1-treated piglets (P < 0.05). The activity of serum superoxide dismutase (SOD) was enhanced by dietary AB, RBC1, and RBC2 (P < 0.05). Serum glutathione (GSH) concentration was elevated by dietary RBC1 and RBC2 (P < 0.05). According to 16S rRNA sequence analysis, AB- and RBC2-treated piglets had a higher relative abundance of Firmicutes and Lachnospiraceae in the colon digesta, and more abundant Lactobacillus was found in RBC1-treated piglets, as compared to the CON group. Additionally, RBC2 supplementation increased the α diversity [Chao1, PD-whole-tree, and observed operational taxonomic units (OTUs)] compared to the CON group. Taken together, the dietary RBC improved the growth performance of weaned piglets. In addition, 10 g/kg of RBC2 in the diet achieved better effects on higher ADG, ileal villi morphology, and stronger antioxidant capacity than dietary AB and RBC1 in weaning piglets.

Heat stress develops with increased total-tract gut permeability, and dietary organic acid and pure botanical supplementation partly restores lactation performance in Holstein dairy cows

To evaluate the effects of heat stress (HS) conditions and dietary organic acid and pure botanical (OA/PB) supplementation on gut permeability and milk production, we enrolled 46 multiparous Holstein cows [208 ± 4.65 dry matter intake (DMI; mean ± SD), 3.0 ± 0.42 lactation, 122 ± 4.92 d pregnant, and 39.2 ± 0.26 kg of milk yield] in a study with a completely randomized design. Cows were assigned to 1 of 4 groups: thermoneutral conditions (TN-Con, n = 12), HS conditions (HS-Con, n = 12), thermoneutral conditions pair-fed to HS-Con (TN-PF, n = 12), or HS supplemented with OA/PB [75 mg/kg of body weight (BW); 25% citric acid, 16.7% sorbic acid, 1.7% thymol, 1.0% vanillin, and 55.6% triglyceride; HS-OAPB, n = 10]. Supplements were delivered twice daily by top-dress; all cows not supplemented with OA/PB received an equivalent amount of the triglyceride used for microencapsulation of the OA/PB supplement as a top-dress. Cows were maintained in thermoneutrality [temperature-humidity index (THI) = 68] during a 7-d acclimation and covariate period. Thereafter, cows remained in thermoneutral conditions or were moved to HS conditions (THI: diurnal change 74 to 82) for 14 d. Cows were milked twice daily. Clinical assessments and BW were recorded, blood was sampled, and gastrointestinal permeability measurements were repeatedly evaluated. The mixed model included fixed effects of treatment, time, and their interaction. Rectal and skin temperatures and respiration rates were greater in HS-Con and HS-OAPB relative to TN-Con. Dry matter intake, water intake, and yields of energy-corrected milk (ECM), protein, and lactose were lower in HS-Con relative to HS-OAPB. Nitrogen efficiency was improved in HS-OAPB relative to HS-Con. Compared with TN-Con and TN-PF, milk yield and ECM were lower in HS-Con cows. Total-tract gastrointestinal permeability measured at d 3 of treatment was greater in HS-Con relative to TN-Con or TN-PF. Plasma total fatty acid concentrations were reduced, whereas insulin concentrations were increased in HS-Con relative to TN-PF. We conclude that exposure to a heat-stress environment increases total-tract gastrointestinal permeability. This study highlights important mechanisms that might account for milk production losses caused by heat stress, independent of changes in DMI. Our observations also suggest that dietary supplementation of OA/PB is a means to partly restore ECM production and improve nitrogen efficiency in dairy cattle experiencing heat stress.

Determination of the available energy, standardized ileal digestibility of amino acids of fermented corn germ meal replacing soybean meal in growing pig diets

Three experiments were conducted to compare the digestible (DE), metabolizable energy (ME), and standardized ileal digestibility (SID) of amino acids (AA) in fermented corn germ meal (FCGM) and soybean meal (SBM), and evaluate the effects of FCGM replacing SBM in growing pig diets. In Exp. 1, 18 barrows with initial body weight (BW) of 60.2 ± 3.40 kg were randomly allotted to 3 treatments with 6 replicates per treatment. The control diet used corn as the only energy ingredient, and 2 test diets were made by replacing 25.8% of corn with FCGM or SBM. The DE and ME of FCGM were less (P < 0.01) than those of SBM. In Exp. 2, 18 barrows (59.3 ± 2.52 kg BW) with ileal T-cannulas were randomly allotted to 3 treatments with 6 replicates per treatment. The SID of arginine, tryptophan and proline were greater (P < 0.05) and the tyrosine was less (P = 0.01) in SBM compared with FCGM. In Exp. 3, 144 growing pigs (56.1 ± 5.22 kg BW) were randomly allotted to 4 treatments with 6 pens per treatment (3 barrows and 3 gilts per pen). Four diets (FCGM0, FCGM10, FCGM20 and FCGM30) were formulated using FCGM to replace 0%, 10%, 20% and 30% of SBM, respectively. The ME and SID values of AA of SBM and FCGM were determined by Exp. 1 and 2. Results showed that increasing FCGM inclusion quadratically (P < 0.05) increased the average daily gain (ADG), average daily feed intake, and the levels of serum immunoglobulin G (IgG) and urea nitrogen, and linearly (P < 0.05) increased the serum IgM, the propanoic acid, butyric acid, total volatile fatty acid (VFA) and the Shannon index of microbiota in feces. Besides, the relative abundance of genus Streptococcus in FCGM0, Lactobacillus in FCGM10 and Lachnospiraceae in FCGM30 were increased (P < 0.05) compared with other treatments. In conclusion, we recommend replacing 11.80% of SBM with FCGM to obtain the optimal ADG of growing pigs. Moreover, as the ratio of FCGM replacing SBM increased in diet, the immunity, intestinal microbiota and total VFA composition of growing pigs were improved.

Isotope-Coded Chemical Derivatization Method for Highly Accurately and Sensitively Quantifying Short-Chain Fatty Acids

Short-chain fatty acids (SCFAs) are major gut microbiota-derived metabolites, which can reshape the intestine and regulate gut immunity. The application of conventional GC methods has been hampered for quantifying low-concentrated SCFAs, such as in serum, saliva, and digesta of germ-free animals. Herein, we established a LC-MS method to quantify SCFAs after 5-(dimethylamino)-1-carbohydrazide-isoquinoline (DMAQ) derivatization. The DMAQ derivatization significantly enhanced the detection sensitivity and improved separation of SCFAs. 2-methylbutyric acid and 3-methylbutyric acid were separately quantitated. Moreover, the matrix effect was diminished using DMAQ-¹³C/¹⁵N-tagged SCFAs as internal standards. The established quantitation method was successfully applied in the analysis of plasma and cecum digesta collected from neonatal piglets, revealing that significant increases in biological SCFA contents in cecum digesta were closely related to the variation of gut microbial diversity. The established quantitation method is capable of sensitively and comprehensively quantifying SCFAs that may provide insights into underlying gut-microbiota functions.

Potential Role of Protocatechuic Acid as Natural Feed Additives in Farm Animal Production

Simple Summary

Protocatechuic acid (PCA) is a phenolic-rich compound that exists in natural plants. Many in vitro studies have reported its antioxidant, anti-inflammatory, anti-microbial properties. Although the health-promoting effects of PCA have been established in human medicine, the applications of PCA as natural feed additives on farm animal production still need to be re-investigated. Therefore, the aim of the review study was to gather research information on PCA to better our understanding of the practical uses of those natural antioxidant-rich feed additives in animal fodder.

Abstract

Restriction on using antibiotics in animal feed that generates demand for antibiotics alternatives in animal breeding. Providing safe food to humans free from the residual effects of antibiotics is a great challenge to animal producers and food-producing industry owners. Medicinal plants and their extracts as feed supplements have been used to promote the growth and health of farm animals for centuries. Protocatechuic acid (PCA) is a phenolic compound that originated from natural plants. For years, the health-promoting role of PCA has been becoming an attraction of research in nutrition and pharmacy. Thus, it can be used as an active natural feed additive while synthetic antibiotics are illegal to use in animal breeding. However, the practical application of PCA in view of dosages in animal nutrition, together with its mode of action on animal health, is not well known. In this regard, this review study has explored the mode of action of PCA and the feasibility of using those compounds in animal nutrition. This review study concludes that phenolic-rich protocatechuic acid as a natural feed additive may be useful in enhancing antioxidant status, immune function, antimicrobial, intestinal health and growth performance of farm animals.

Microencapsulated essential oils combined with organic acids improves immune antioxidant capacity and intestinal barrier function as well as modulates the hindgut microbial community in piglets

Background

The objective of this experiment was to evaluate the effect of a combination of microencapsulated essential oils and organic acids (MOA) on growth performance, immuno-antioxidant status, intestinal barrier function and microbial structure of the hindgut in piglets. A total of 120 piglets (Duroc × [Landrace × Yorkshire]; weighted 7.66 ± 1.79 kg, weaned at d 28) were randomly selected and allocated to 3 treatments with 4 replicates per group and 10 piglets per replicate according to the initial body weight and gender. The dietary treatments were as follows: 1) basal diet (Ctrl); 2) Ctrl + chlortetracycline (75 mg/kg) (AGP); 3) Ctrl+ MOA (1500 mg/kg). The experiment period was lasted for 21 d.

Results

Compared to the Ctrl group, dietary supplemented MOA alleviated (P < 0.05) the diarrhea rate from d 12 to 21, enhanced (P < 0.05) the concentration of serum interlukin-10 and glutathione peroxidase in piglets on d 11 after weaning and serum superoxide dismutase in 21-day piglets. The MOA group also improved (P < 0.05) the apparent digestibility of dry matter (DM), organic matter (OM) and gross energy (GE), up-regulated (P < 0.05) the mRNA expression level of occludin, claudin-1 and mucin-2 in ileum and increased (P < 0.05) the contents of propionic and butyric acids in the cecum of piglets. The MOA group modulated the cecal and colonic microbial community structure and increased (P < 0.05) the abundance of Faecalibacterium and Muribaculaceae in cecum and Streptococcus and Weissella in colon. Additionally, AGP group decreased (P < 0.05) apparent digestibility of DM, OM and GE as well as down-regulated (P < 0.05) relative gene expression level of claudin-1 in duodenum and jejunum, ZO-1 and mucin-1 in jejunum of piglets.

Conclusion

In summary, dietary supplemented MOA alleviated diarrhea and improved nutrient apparent digestibility in piglets via enhancing immuno-antioxidant properties, increasing digestive enzyme activity, up-regulating the expression of intestinal barrier-related genes, and modifying the microbial community structure of the cecum and colon. Therefore, dietary supplementation with MOA as an alternative to antibiotics was feasible to improve intestinal health of piglets in practical production.

Supplementation of Mixed Organic Acids Improves Growth Performance, Meat Quality, Gut Morphology and Volatile Fatty Acids of Broiler Chicken

Simple Summary

Organic acid as a green feed additive is increasingly favoured by enterprises and scholars, but little emphasis has been placed on the effect of organic acids on broiler meat quality and lipid profile. Therefore, this study observed that mixed organic acids improve broiler growth performance, meat quality as well as muscle lipid profile, which suggests that mixed organic acids can be an effective measure to prevent meat quality decline in chicken meat.

Abstract

Background: Organic acid as a green feed additive is increasingly favoured by enterprises and scholars, but little emphasis has been placed on the effect of organic acids on broiler meat quality. Methods: A total of 192 male chicks (one-day-old, weighted 48.40 ± 0.64 g) were selected to investigate the effect of mixed organic acids (MOA) on growth performance, meat quality as well as fatty acids profile. Chicks were randomly allocated to three treatments with eight replicates and eight chicks per replicate, including a corn–soybean basal diet with 0 (CON), 3000 mg/kg (low MOA; LMOA), and 6000 mg/kg (high MOA; HMOA) MOA. The experiment was divided into starter (d 1–d 21) and grower (d 22–d 42) phases. Results: Broilers supplemented with LMOA and HMOA enhanced (p < 0.05) the final body weight and average daily gain in the grower and overall phases. An improved (p < 0.05) feed conversion ratio in the grower and overall phases was observed in broilers supplemented with LMOA. The breast and thigh muscles pH24h were higher (p < 0.05) in broilers fed with HMOA and the redness in thigh meat was also improved (p < 0.05). Additionally, supplementing LMOA increased (p < 0.05) the saturated fatty acids, unsaturated fatty acids and the ratio of polyunsaturated fatty acids to saturated fatty acids in breast meat. A positive effect occurred (p < 0.05) on jejunal villus height and ileal crypt depth in 21 d broilers supplemented with HMOA. Conclusion: Our findings indicated that dietary supplementation of MOA could improve the growth performance, meat quality, and fatty acids profile, as well as intestinal morphology. Furthermore, diets supplemented with mixed organic acids at 3000 mg/kg may be more desirable, considering the overall experimental results in broilers.