Evaluation of different blends of medium-chain fatty acids, lactic acid, and monolaurin on nursery pig growth performance. Transl Anim Sci 2020;4:txaa024. [PMID: 32705023 DOI: 10.1093/tas/txaa024]

Effects of zinc oxide and monoglyceride blend on intestinal immune, health and microbiota responses of weanling pigs

Organic acids are increasingly being investigated as alternatives to zinc oxide (ZnO) in nursery pig diets. Monoglycerides can act in distal parts of the intestine, promoting intestinal health, also reducing bacterial fermentation in hindgut. This study aimed to determine the effects of dietary supplementation based on a blend of monoglycerides (C4:C8:C10) (MBLEND) in replacement to ZnO during the nursery phase on growth-performance and intestinal health. Ninety-six piglets were used (average weight 7.08 ± 0.837 kg) with 25 days of age during 42 days, divided into three treatments and eight replicates in a randomized block design. The treatments were: CON - Negative control (basal diet without additive supplementation); MBLEND - Fatty acids (basal diet with monoglycerides blend (C4:C8:C10) additive supplementation at 1.5 kg/ton in the pre-initial 1 and pre-initial 2 phases, 1.0 kg/ton in the initial 1 and initial 2 phases) and ZnO - Zinc oxide (basal diet with zinc oxide supplementation at 3000 ppm in the pre-initial 1, pre-initial 2 and initial 1 phases, 2000 ppm in the initial 2 phase). Both ZnO and MBLEND groups did not influence (P>0.05) growth performance during all phases. The inclusion of the MBLEND improved (P<0.05) dry matter (DM), crude protein (CP), and ashes digestibility when compared to CON and ZnO groups. The use of ZnO reduced (P<0.05) IL-1 β cytokine expression in the piglets' jejunal mucosa. ZnO increased evenness and affected beta-diversity (P<0.05) compared to CON and MBLEND. The ZnO group increased Tannerellaceae, Bacteroidaceae, and Muribaculaceae families and reduced Escherichia Coli-Shigella and Desulfovibrio generas (q<0.05). Although there were similar results on growth performance, ZnO modulated cecal microbiota and reduced inflammatory ileal cytokines and MBLEND improved protein and ashes digestibility.

Effects of Medium- and Short-Chain Fatty Acids on Growth Performance, Nutrient Digestibility, Gut Microbiota and Immune Function in Weaned Piglets

The aim of this study was to investigate the combination effects of α-glycerol monolaurate (GML) and glyceryl tributyrate (TB) on growth performance, nutrient digestibility, gut microbiota, and immune function in weaned piglets. A total of 120 weaned piglets with an average body weight (BW) of 6.88 kg were randomly allocated to one of the three dietary treatments: (1) CON: a basal diet; (2) 0.1%: a basal diet with 0.1% MSCFA (GML/TB = 1:1); (3) 0.2%: a basal diet with 0.2% MSCFA (GML/TB = 1:1). The experiment lasted 28 days. There were no differences on average daily growth (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR). Supplementation with 0.1% MSCFA increased apparent total tract digestibility (ATTD) of crude protein (CP) and gross energy (GE, p < 0.05) on d 14 and increased GE (p < 0.05) on d 28 compared with the CON group. The ATTD of dry matter (DM), organic matter (OM) and crude protein (CP) of piglets supplemented with 0.1% MSCFA was higher (p < 0.05). Compared with the CON group, supplementation with 0.1% MSCFA increased immunoglobulin M (IgM) concentration, decreased interleukin-6 (IL-6) content (p < 0.05) on d 14 and decreased malonaldehyde (MDA), interleukin-1beta (IL-1β), IL-6 concentrations (p < 0.05) on d 28. Supplementation with 0.1% MSCFA increased total antioxidant capacity (T-AOC) concentration (p < 0.05), decreased GSH-Px, MDA content (p < 0.05) in jejunum compared with the CON group. Moreover, supplementation with MSCFA increased the activity of duodenal lipase (p < 0.05) and the abundance of firmicutes and decreased the abundance of proteobacteria compared with the CON group. Overall, supplementation with MSCFA can improve nutrient digestibility, enhance immunity and antioxidant capacity, and improve the intestinal health of piglets. The combined use of MSCFA is a nutrition regulation strategy worthy of further exploration in modern animal husbandry.

Medium-chain fatty acid triglycerides improve feed intake and oxidative stress of finishing bulls by regulating ghrelin concentration and gastrointestinal tract microorganisms and rumen metabolites

BACKGROUND

As a feed additive, medium-chain fatty acids (MCFAs)/medium-chain fatty acid triglycerides (MCTs) have been used in ruminant production, but mostly added in the form of mixed esters. Studies have shown that MCTs may have a positive effect on feed intake or oxidative stress in animals, but it is unclear which MCT could play a role, and the mechanism has not been elucidated. In this study, the effects of individual MCT on growth performance, serum intake-related hormones, and oxidative stress indices in finishing bulls were investigated and further studied the effects of MCT supplementation on gastrointestinal tract bacteria and rumen fluid metabolomics.

RESULTS

Four ruminally fistulated Yanbian cattle (bulls) were selected in 4 × 4 Latin square designs and allocated to four treatment groups: a control group (CON) fed a basal diet (total mixed ration, TMR), three groups fed a basal diet supplemented with 60 g/bull/day glycerol monocaprylin (GMC, C8), glycerol monodecanoate (GMD, C10), and glycerol monolaurate (GML, C12), respectively. Compared with the CON group, GMD tended to increase the dry matter intake (DMI) of finishing bulls (P = 0.069). Compared with the CON group, GMD significantly increased the concentration of ghrelin O-acyl transferase (GOAT), total ghrelin (TG), acylated ghrelin (AG), and orexins (P < 0.05) and significantly decreased the concentrations of hydrogen peroxide (H2O2), malondialdehyde, reactive oxygen species (ROS), and lipopolysaccharides (LPS) in the serum of finishing bulls (P < 0.05). Compared with the CON group, GMD and GML significantly increased the concentrations of total antioxidant capacity (T-AOC), catalase, glutathione peroxidase (GSH-PX), glutathione reductase (GR), and nitric oxide (NO) in the serum of finishing bulls (P < 0.05). Compared with the CON group, there were 5, 14, and 6 significantly different bacteria in the rumen digesta in the C8, C10, and C12 groups, respectively; there were 3, 10, and 5 significantly different bacteria in the rumen fluid in the C8, C10, and C12 groups, respectively; and only one differential bacteria (genus level) in the feces among the four treatment groups. Compared with the CON group, there were 3, 14, and 15 significantly differential metabolites identified under positive ionization mode in the C8, C10, and C12 groups, respectively, while under negative ionization mode were 3, 11 and 14, respectively. Correlation analysis showed that there was a significant correlation between DMI, GOAT, AG, GSH-PX, LPS, gastrointestinal tract bacteria, and rumen fluid metabolites.

CONCLUSIONS

Our findings revealed that different types of MCTs have different application effects in ruminants. Among them, GMD may improve the feed intake of finishing bulls by stimulating the secretion of AG. GMD and GML may change gastrointestinal tract microorganisms and produce specific rumen metabolites to improve the oxidative stress of finishing bulls, and ghrelin may also be involved. This study enlightens the potential mechanisms by which MCT improves feed intake and oxidative stress in finishing bulls. Video Abstract.

Effects of monoglyceride blend on systemic and intestinal immune responses, and gut health of weaned pigs experimentally infected with a pathogenic Escherichia coli

BACKGROUND

Monoglycerides have emerged as a promising alternative to conventional practices due to their biological activities, including antimicrobial properties. However, few studies have assessed the efficacy of monoglyceride blend on weaned pigs and their impacts on performance, immune response, and gut health using a disease challenge model. Therefore, this study aimed to investigate the effects of dietary monoglycerides of short- and medium-chain fatty acids on the immunity and gut health of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli F18.

RESULTS

Pigs supplemented with high-dose zinc oxide (ZNO) had greater (P < 0.05) growth performance than other treatments, but no difference was observed in average daily feed intake between ZNO and monoglycerides groups during the post-challenge period. Pigs in ZNO and antibiotic groups had lower (P < 0.05) severity of diarrhea than control, but the severity of diarrhea was not different between antibiotic and monoglycerides groups. Pigs fed with monoglycerides or ZNO had lower (P < 0.05) serum haptoglobin on d 2 or 5 post-inoculation than control. Pigs in ZNO had greater (P < 0.05) goblet cell numbers per villus, villus area and height, and villus height:crypt depth ratio (VH:CD) in duodenum on d 5 post-inoculation than pigs in other treatments. Pigs supplemented with monoglycerides, ZNO, or antibiotics had reduced (P < 0.05) ileal crypt depth compared with control on d 5 post-inoculation, contributing to the increase (P = 0.06) in VH:CD. Consistently, pigs in ZNO expressed the lowest (P < 0.05) TNFa, IL6, IL10, IL12, IL1A, IL1B, and PTGS2 in ileal mucosa on d 5 post-inoculation, and no difference was observed in the expression of those genes between ZNO and monoglycerides. Supplementation of ZNO and antibiotic had significant impacts on metabolic pathways in the serum compared with control, particularly on carbohydrate and amino acid metabolism, while limited impacts on serum metabolites were observed in monoglycerides group when compared with control.

CONCLUSIONS

The results suggest that supplementation of monoglyceride blend may enhance disease resistance of weaned pigs by alleviating the severity of diarrhea and mitigating intestinal and systemic inflammation, although the effectiveness may not be comparable to high-dose zinc oxide.

Medium chain fatty acid supplementation improves animal metabolic and immune status during the transition period: A study on dairy cattle

The transition period is the stage of the high incidence of metabolic and infectious diseases in dairy cows. Improving transition dairy cows' health is crucial for the industry. This study aimed to determine the effects of dietary supplementation medium-chain fatty acids (MCFAs) on immune function, metabolic status, performance of transition dairy cows. Twenty multiparous Holstein cows randomly assigned to two treatments at 35 d before calving. 1) CON (fed the basal 2) MCFA treatment (basal diet was supplemented at an additional 20 g MCFAs mixture every day) until 70 d after calving. The results showed that the serum amyloid A myeloperoxidase concentrations in the blood of cows in MCFA treatment significantly decreased during the early lactation (from 1 d to 28 d after calving) 0.03, 0.04, respectively) compared with the CON, while the tumor necrosis factor concentration was significantly decreased at 56 d after calving (P = 0.02). In addition, the concentration of insulin in the pre-calving (from 21 d before calving to calving) blood of cows in MCFA treatment was significantly decreased (P = 0.04), and concentration of triglyceride also showed a downward trend at 28 d after calving 0.07). Meanwhile, MCFAs supplementation significantly decreased the concentrations of lithocholic acid, hyodeoxycholic acid, and hyocholic acid in the blood at 1 d calving (P = 0.02, < 0.01, < 0.01, respectively), and the level of hyocholic acid taurocholic acid concentrations (P < 0.01, = 0.01, respectively) decreased dramatically at 14 d after calving. However, compared with the CON, the pre-calving dry matter intake and the early lactation milk yield in MCFA treatment were significantly decreased (P = 0.05, 0.02, respectively). In conclusion, MCFAs supplementation transition diet could improve the immune function and metabolic status of dairy cows, and the health of transition cows might be beneficial from the endocrine status.

In vitro and in vivo antiviral activity of monolaurin against Seneca Valley virus

Introduction

Surveillance of the Seneca Valley virus (SVV) shows a disproportionately higher incidence on Chinese pig farms. Currently, there are no vaccines or drugs to treat SVV infection effectively and effective treatment options are urgently needed.

Methods

In this study, we evaluated the antiviral activity of the following medium-chain fatty acids (MCFAs) or triglycerides (MCTs) against SVV: caprylic acid, caprylic monoglyceride, capric monoglyceride, and monolaurin.

Results

In vitro experiments showed that monolaurin inhibited viral replication by up to 80%, while in vivo studies showed that monolaurin reduced clinical manifestations, viral load, and organ damage in SVV-infected piglets. Monolaurin significantly reduced the release of inflammatory cytokines and promoted the release of interferon-γ, which enhanced the viral clearance activity of this type of MCFA.

Discussion

Therefore, monolaurin is a potentially effective candidate for the treatment of SVV infection in pigs.

Effects of formic acid and glycerol monolaurate on weanling pig growth performance, fecal consistency, fecal microbiota, and serum immunity

A total of 350 weanling pigs (DNA 400 × 200; initially, 5.67 ± 0.06 kg BW) were used in a 42-day study with 5 pigs per pen and 14 replicate pens per treatment. At weaning, pigs were allotted to pens in a completely randomized design and pens of pigs were randomly assigned to one of five dietary treatments: 1) negative control (CON; standard nursery diet containing only 150 ppm Zn from trace mineral premix and no acidifier); 2) control diet with 3,000 ppm added zinc from ZnO included in phase 1 and 2,000 ppm added zinc from ZnO included in phase 2 (ZnO); 3) control diet with 0.70% formic acid (FA; Amasil NA; BASF, Florham, NJ); 4) control diet with 0.18% glycerol monolaurate (GML; Natural Biologics GML, Natural Biologics, Newfield, NY); and 5) control diet with a 1.0% blend of formic acid and glycerol monolaurate (FORMI; FORMI 3G, ADDCON GmbH, Bitterfeld-Wolfen, Germany). Pigs were fed treatment diets from d 0 to d 28 and were then fed a common diet from d 28 to d 42. From days 0 to 7, pigs fed ZnO or FORMI had increased (P = 0.03) ADG compared to pigs fed CON, with no difference in feed intake (P > 0.05). Overall, pigs fed GML had reduced (P < 0.0001) ADG compared with those fed the CON, ZnO, or FORMI diets. Fecal DM was evaluated from days 7 to 28 and there was a treatment × day interaction (P = 0.04). Pigs fed GML had a lower fecal DM % on day 7, but a higher fecal DM % on days 14 and 21; however, no differences in fecal DM were observed on day 28. Fresh fecal samples were collected from the same randomly selected pig on days 0 and 14 (70 pigs total;14 pigs per treatment) for analysis of fecal microbial populations using 16S rDNA sequencing. Dietary treatment did not significantly impact fecal microbiota at the phyla level, but pigs fed ZnO had an increased relative abundance (P < 0.01) of the family Clostridiaceae. A blood sample was also collected from one pig per pen on days 0 and 14 for analysis of serum IgA, IgG, and TNF-α. There was no evidence that dietary treatment effected IgA, IgG, or TNF-α concentrations. The effect of sampling day was significant (P < 0.05), where circulating IgA and TNF-α was increased and IgG was decreased from days 0 to 14. In summary, there is potential for a blend of formic acid and GML to improve growth performance immediately post-weaning without negatively impacting fecal consistency. Formic acid and GML alone or in combination did not impact fecal microbial populations or serum immune parameters.

Monolaurin Confers a Protective Effect Against Porcine Epidemic Diarrhea Virus Infection in Piglets by Regulating the Interferon Pathway

Porcine epidemic diarrhea virus (PEDV) has reemerged as the main pathogen of piglets due to its high mutation feature. Monolaurin (ML) is a natural compound with a wide range of antibacterial and antiviral activities. However, the role of ML in PEDV infection is still unknown. This study aimed to evaluate the effect of ML on the growth performance, intestinal function, virus replication and cytokine response in piglets infected with PEDV, and to reveal the mechanism through proteomics analysis. Piglets were orally administrated with ML at a dose of 100 mg/kg·BW for 7 days before PEDV infection. Results showed that although there was no significant effect on the growth performance of piglets, ML administration alleviated the diarrhea caused by PEDV infection. ML administration promoted the recovery of intestinal villi, thereby improving intestinal function. Meanwhile, PEDV replication was significantly inhibited, and PEDV-induced expression of IL-6 and IL-8 were decreased with ML administration. Proteomics analyses showed that 38 proteins were differentially expressed between PEDV and ML+PEDV groups and were significantly enriched in the interferon-related pathways. This suggests ML could promote the restoration of homeostasis by regulating the interferon pathway. Overall, the present study demonstrated ML could confer a protective effect against PEDV infection in piglets and may be developed as a drug or feed additive to prevent and control PEDV disease.

Comparison of caproic acid and monolaurin with zinc oxide and benzoic acid; effect on growth performance of weaned pigs

Medium chain organic acids (MCOA) offer the potential to replace zinc oxide, without dependence on antibiotic use, and can replace or reduce the use of benzoic acid in pig production. A study was conducted to evaluate the effects of caproic acid (C6) and C12 monolaurin (C12M) on the growth performance of weaned pigs, in comparison with zinc oxide (ZnO) and benzoic acid (BA). Specifically, the trial examined whether MCOA, at a reduced inclusion level of BA, could maintain performance levels of pigs similar to those receiving a higher inclusion level of BA. In total, 240 pigs from weaning until 27 d post-weaning were used in a completely randomised block trial with six treatments and eight replicate pens per treatment. Treatments were: (1) control (CON), basal diet (BD); (2) BD+ZnO (ZnO); (3) BD+5,000 mg/kg BA (BA); (4) BD+2,500 mg/kg BA+2,000 mg/kg C12M+700 mg/kg C6 (BAlow/MCOA); (5) BD+2,000 mg/kg C12M+700 mg/kg C6 (MCOA); (6) BD+1000 mg/kg C12M+700 mg/kg C6 (MCOAlow). Feed and water were provided ad libitum. Pigs receiving BA or BA low/MCOA had improved feed conversion ration (FCR) during the period 0-14 days, compared with control pigs (1.02 vs 1.17, P<0.05; 1.06 vs 1.17; P=0.084, respectively). The FCR of pigs receiving BAlow/MCOA was similar to those receiving BA at the higher inclusion-level. Pigs showed good health throughout the study, as indicated by clinical and faecal scores. Replacement of ZnO was inconclusive and further studies with more challenging health conditions are required to conclude benefits.

Effects of α-glycerol monolaurate on intestinal morphology, nutrient digestibility, serum profiles, and gut microbiota in weaned piglets

This experiment was conducted to investigate the effects of dietary supplementation of α-glycerol monolaurate (α-GML) on the growth performance, nutrient digestibility, serum profiles, intestinal morphology, and gut microbiota of weaned piglets. A total of 96 healthy 28-d-old (Duroc × Landrace × Yorkshire) weaned piglets with body weight of 8.34 ± 0.05 kg were randomly divided into 2 treatment groups with 6 replicate pens and 8 piglets per pen. The control group was fed a basal diet and the experimental group was fed the basal diet supplemented with 1,000 mg/kg α-GML. The experiment lasted for 28 d. Dietary supplementation with α-GML had no effect on average daily gain, average daily feed intake, or gain to feed ratio in piglets (P > 0.05); however, it reduced (P < 0.05) diarrhea rate of piglets on days 15 to 28. The apparent total tract digestibility of dry matter (DM), crude protein (CP), ether extract (EE), and gross energy (GE) on day 14, and DM, organic matter, CP, EE, and GE on day 28 increased (P < 0.05) with α-GML supplementation. Moreover, higher (P < 0.05) glutathione peroxidase activity and interleukin-10 (IL-10) concentration, and lower (P < 0.05) malondialdehyde and tumor necrosis factor-α concentrations were observed in piglets supplemented with α-GML compared with the control group on day 14. Compared with the control group, the villus height/crypt depth in the duodenum and villus height in the jejunum and ileum were significantly greater (P < 0.05) in the α-GML group. Dietary α-GML supplementation significantly increased (P < 0.05) the relative abundance of Firmicutes, while decreasing (P < 0.05) Bacteroidota and Campilobacterota in the cecal contents; significantly increased (P < 0.05) the relative proportion of Lactobacillus and Blautia species, reduced (P < 0.05) Eubacterium_rectale_ATCC_33656, Campylobacter, and uncultured_bacterium_Alloprevotella species. Thus, dietary α-GML supplementation at 1,000 mg/kg reduces diarrhea rate, improves intestinal morphology, nutrient digestibility, antioxidant capacity, and immune status, and ameliorates gut microbiota in weaned piglets.

Inhibition of African swine fever virus in liquid and feed by medium-chain fatty acids and glycerol monolaurate

BACKGROUND

The ongoing African swine fever virus (ASFv) epidemic has had a major impact on pig production globally and biosecurity efforts to curb ASFv infectivity and transmission are a high priority. It has been recently identified that feed and feed ingredients, along with drinking water, can serve as transmission vehicles and might facilitate transboundary spread of ASFv. Thus, it is important to test the antiviral activity of regulatory compatible, antiviral feed additives that might inhibit ASFv infectivity in feed. One promising group of feed additive candidates includes medium-chain fatty acids (MCFA) and monoglyceride derivatives, which are known to disrupt the lipid membrane surrounding certain enveloped viruses and bacteria.

RESULTS

The antiviral activities of selected MCFA, namely caprylic, capric, and lauric acids, and a related monoglyceride, glycerol monolaurate (GML), to inhibit ASFv in liquid and feed conditions were investigated and suitable compounds and inclusion rates were identified that might be useful for mitigating ASFv in feed environments. Antiviral assays showed that all tested MCFA and GML inhibit ASFv. GML was more potent than MCFA because it worked at a lower concentration and inhibited ASFv due to direct virucidal activity along with one or more other antiviral mechanisms. Dose-dependent feed experiments further showed that sufficiently high GML doses can significantly reduce ASFv infectivity in feed in a linear manner in periods as short as 30 min, as determined by infectious viral titer measurements. Enzyme-linked immunosorbent assay (ELISA) experiments revealed that GML treatment also hinders antibody recognition of the membrane-associated ASFv p72 structural protein, which likely relates to protein conformational changes arising from viral membrane disruption.

CONCLUSION

Together, the findings in this study indicate that MCFA and GML inhibit ASFv in liquid conditions and that GML is also able to reduce ASFv infectivity in feed, which may help to curb disease transmission.

Dietary Supplementation of Inorganic, Organic, and Fatty Acids in Pig: A Review

Simple Summary

The role of acids in pig feed strategies has changed from feed acidifier and preservative to growth promoter and antibiotics substitute. Since the 2006 European banning of growth promoters in the livestock sector, several feed additives have been tested with the goal of identifying molecules with the greatest beneficial antimicrobial, growth-enhancing, or disease-preventing abilities. These properties have been identified among various acids, ranging from inexpensive inorganic acids to organic and fatty acids, and these have been widely used in pig production. Acids are mainly used during the weaning period, which is considered one of the most critical phases in pig farming, as well as during gestation, lactation, and fattening. Such supplementation generally yields improved growth performance and increased feed efficiency; these effects are the consequences of different modes of action acting on the microbiome composition, gut mucosa morphology, enzyme activity, and animal energy metabolism.

Abstract

Reduction of antibiotic use has been a hot topic of research over the past decades. The European ban on growth-promoter use has increased the use of feed additivities that can enhance animal growth performance and health status, particularly during critical and stressful phases of life. Pig farming is characterized by several stressful periods, such as the weaning phase, and studies have suggested that the proper use of feed additives during stress could prevent disease and enhance performance through modulation of the gastrointestinal tract mucosa and microbiome. The types of feed additive include acids, minerals, prebiotics, probiotics, yeast, nucleotides, and phytoproducts. This review focuses on commonly used acids, classified as inorganic, organic, and fatty acids, and their beneficial and potential effects, which are widely reported in the bibliography. Acids have long been used as feed acidifiers and preservatives, and were more recently introduced into feed formulated for young pigs with the goal of stabilizing the stomach pH to offset their reduced digestive capacity. In addition, some organic acids represent intermediary products of the tricarboxylic acid cycle (TCA), and thus could be considered an energy source. Moreover, antimicrobial properties have been exploited to modulate microbiota populations and reduce pathogenic bacteria. Given these potential benefits, organic acids are no longer seen as simple acidifiers, but rather as growth promoters and potential antibiotic substitutes owing to their beneficial action on the gastrointestinal tract (GIT).