In vitro susceptibility of swine pathogens to feed additives and active ingredients with potential as antibiotic replacements

A comprehensive review of medium chain monoglycerides on metabolic pathways, nutritional and functional properties, nanotechnology formulations and applications in food system

A large and growing body of literature has investigated the broad antibacterial spectrum and strong synergistic antimicrobial activity of medium chain monoglycerides (MCMs) have been widely investigated. Recently, more and more researches have focused on the regulation of MCMs on metabolic health and gut microbiota both in vivo and in vitro. The current review summarizes the digestion, absorption and metabolism of MCMs. Subsequently, it focuses on the functional and nutritional properties of MCMs, including the antibacterial and antiviral characteristics, the modulation of metabolic balance, the regulation of gut microbiota, and the improvement in intestinal health. Additionally, we discuss the most recent developments and application of MCMs using nanotechnologies in food industry, poultry and pharmaceutical industry. Additionally, we analyze recent application examples of MCMs and their nanotechnology formation used in food. The development of nanotechnology platforms facilitating molecular encapsulation and functional presentation contribute to the application of hydrophobic fatty acids and monoglycerides in food preservation and their antibacterial effectiveness. This study emphasizes the metabolic mechanisms and biological activity of MCMs by summarizing the prevailing state of knowledge on this topic, as well as providing insights into prospective techniques for developing the beneficial applications of MCMs to realize the industrialized production.

Evaluation of tributyrin supplementation in milk replacer on diarrhoea occurrence in pre-weaning Holstein calves

Neonatal calf diarrhoea is one of the most important health challenges in cattle herds causing substantial economic losses and antimicrobial use. Due to the raising problem of antimicrobial resistance, effective alternatives are urgently required, in line with European policies. The aim of this study was to evaluate the effect of tributyrin supplementation in milk replacer on diarrhoea, performance and metabolic status in preweaning Holstein calves. Twelve newborn calves, after colostrum administration, were randomly allotted in two experimental groups for 42 days: control (CTRL) fed milk replacer, tributyrin (TRIB) fed milk replacer supplemented with 0.3% of liquid tributyrin on milk powder weight. Calves BW was recorded on a weekly basis from day 7 to day 42, and feed intake was recorded daily to calculate zootechnical performance. Faecal consistency was assessed daily through the faecal score (0-3 scale; considering diarrhoea moderate = 2 and severe = 3). Faecal samples were collected weekly from rectal ampulla for microbiological analysis by plate counting method evaluating the number of total bacteria, lactic acid bacteria and coliform bacteria. On day 0 and day 42, individual blood samples were collected from jugular vein for metabolic profile analysis. Serum samples of day 42 were also evaluated for the antioxidant barrier using a colorimetric test, while glucagon-like peptide 2 and diamine oxidase concentrations were measured through immunoenzymatic assays. Tributyrin supplementation did not influence the zootechnical performance of calves over 42 days of trial. Diarrhoea frequency was significantly lower in TRIB compared to CTRL group (27.91 and 38.37%; P < 0.01) considering the whole experimental period. In particular, the major effect was observed for moderate diarrhoea in TRIB group that showed a significantly reduced frequency compared to CTRL (P < 0.01) thus suggesting a preventive effect of tributyrin. Faecal total bacterial, lactic acid and coliform bacteria counts did not show differences between groups. Urea serum concentrations tended to be lower in TRIB compared to CTRL, indicating an efficient utilisation of dietary protein. Antioxidant barrier and glucagon-like peptide 2 were comparable between CTRL and TRIB on day 42. Diamine oxidase concentrations were significantly decreased in TRIB compared to CTRL group after 42 days of trial (P < 0.01), suggesting a higher gut epithelial integrity probably due to lower diarrhoea frequency and the nourish effect of tributyrin on enterocytes. In conclusion, tributyrin could be considered as a valuable bioactive feed additive to decrease the neonatal diarrhoea occurrence and support intestinal integrity in preweaning calves.

Antimicrobial monoglycerides for swine and poultry applications

The development of natural, broadly acting antimicrobial solutions to combat viral and bacterial pathogens is a high priority for the livestock industry. Herein, we cover the latest progress in utilizing lipid-based monoglycerides as feed additives to address some of the biggest challenges in animal agriculture. The current industry needs for effective antimicrobial strategies are introduced before discussing why medium-chain monoglycerides are a promising solution due to attractive molecular features and biological functions. We then critically analyze recent application examples in which case monoglycerides demonstrated superior activity to prevent feed transmission of viruses in swine and to mitigate bacterial infections in poultry along with gut microbiome modulation capabilities. Future innovation strategies are also suggested to expand the range of application possibilities and to enable new monoglyceride delivery options.

The Feed Additive Potassium Diformate Prevents Salmonella enterica Serovar Pullorum Infection and Affects Intestinal Flora in Chickens

Extensive studies have shown that potassium diformate (KDF), an antibiotic substitute used as a feed additive, improves animal growth performance, although there is less direct evidence of its preventive effect on bacterial infections and its influence on the intestinal flora of animals. In this study, the inhibition effect of KDF on Salmonella enterica serovar Pullorum, an important enteric pathogen causing pullorum disease, was investigated in vitro and on a chicken infection model. The effect of KDF on the diversities and structures of chicken duodenal and cecum flora were also investigated using 16S rRNA gene sequencing. The results showed that addition of 0.5% KDF in feed or 0.1% KDF in drinking water significantly reduced the bacterial loads and the degree of pathological changes in the cecum, improved digestion and reduced the pH of the gastrointestinal tract of chickens infected with S. pullorum. KDF also significantly modified the diversity and abundance of intestinal microflorae in chickens. In particular, it promoted the colonization of several probiotics, such as Bacteroides, Blautia, Ruminococcus_torques_group and Faecalibacteriumm, which are involved in maintenance of the intestinal barrier, modulation of inflammation, energy supply for intestinal cells and pathogen resistance. These results enrich the theoretical basis for the clinical application of KDF in chickens.

Comparison of medium chain organic acids with zinc oxide and benzoic acid; effect on growth performance of pigs

Medium chain organic acids (MCOA) show strong and specific antimicrobial activity and may be useful as part of an antibiotic reduction strategy. Two trials were conducted to evaluate the effect of MCOA on growth performance of pigs in comparison with benzoic acid (BA) and ZnO (ZnO). Each used 240 pigs in a randomised complete block design with six treatments in eight replicate pens. Trial 1 tested a blend of C6:0, C8:0, C10:0 and C12:0 for 56 d post-weaning. Treatments were (1) control basal diet (BD), (2) BD+ZnO (3) BD+ZnO+BA, (4) BD+MCOA (5) BD+MCOA+ZnO, (6) BD+MCOA+BA. Pigs receiving MCOA+BA showed higher average daily liveweight gain in the grower period (849 g/d) than pigs receiving the control diet (773 g/d) or the ZnO treatment (779 g/d; P=0.040), grew 7% more efficiently (P=0.008) and were 3.02 kg heavier at 56 d than control pigs. Trial 2 tested the MCOA blend at two inclusion levels in comparison with C6:0/C12:0 (50/50) and C6:0/C12 monolaurin (C12M; 50/50), for 28 d post-weaning. Treatments were (1) control basal diet, (2) BD+ZnO (3) BD+1,500 mg/kg MCOA (4) BD+750 mg/kg MCOA (5) BD+ C6/C12 (total 3,000 mg/kg), (6) BD + C6/C12M (total 3,000 mg/kg). Pigs receiving 750 mg/kg MCOA grew more slowly than those receiving C6/C12M or ZnO (P<0.05) to d 21. Pigs fed ZnO were 1.61 kg heavier than these pigs (P<0.05), while those fed C6/C12M were 1.29 kg heavier (P<0.05) at d 21. During 0-14 d pigs fed ZnO showed the best feed conversion ratio (FCR), but at 15-28 d the improvement was no longer seen. Both the C6/C12 and the C6/C12M treatments appeared to improve FCR during this second phase (P<0.01). The results suggested that supplementation with a combination of MCOA and BA may be a promising strategy to improve growth performance while replacing ZnO and reducing antibiotic dependence.

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.