Low-Protein Diet Supplemented with Medium-Chain Fatty Acid Glycerides Improves the Growth Performance and Intestinal Function in Post-Weaning Piglets

Dietary supplementation with a blend composed of carvacrol, tannic acid derived from Castanea sativa and Glycyrrhiza glabra, and glycerides of medium chain fatty acids for weanling piglets raised in commercial farm

This study aimed to evaluate the dietary administration of a blend composed of carvacrol, tannic acid derived from Castanea sativa mill and Glycyrrhiza glabra, medium chain fatty acids (MCFAs) glycerides for weanling piglets. An in vitro digestion followed by total phenolic content (TPC) and total antioxidant activity (TAC) assessment was performed before the in vivo application. At weaning, a total of 210 piglets were randomly allocated to two experimental treatments (7 replicates/15 piglets for each replicate). Control group (CTR) was fed a standard basal diet while the treated group (T) was fed the basal diet mixed with 1.500 mg/kg of blend. After in vitro digestion, TPC and TAC evidenced peaks at the end of oral and gastric phases in comparison to the intestinal one in line with the high content of phenolic compound (P < 0.05). Treatment conditioned body weight and average daily gain (P < 0.05), fecal score on 6, 7, and 8 d after weaning (P < 0.05). At 35d, the T group showed a decrease in salivary cortisol compared to CTR (P < 0.05). Duodenum and jejunum sections of T piglets revealed higher villi (P < 0.05), deeper crypts (P < 0.01), and increased V/C ratio (P < 0.01). CTR showed a higher expression of duodenal Occludin (P < 0.05). Jejunal E-cadherin and Occludin were more expressed in T jejunum sections (P < 0.05). Twelve differentially abundant genera were identified in T group caecal samples. Potentially harmful Clostridium sensu stricto 13 was reduced by the treatment (P < 0.05). In conclusion, the tested blend positively affected salivary stress markers and the gut health of weaned piglets.

Effects of dietary energy levels on microorganisms and short-chain fatty acids of rumen and tight junction proteins in Honghe Yellow cattle

This study was conducted to investigate the effects of dietary energy levels on microorganisms and short-chain fatty acids (SCFAs) of rumen and the expression of tight junction proteins in Honghe Yellow cattle. A total of fifteen male Honghe Yellow cattle were randomly divided into three treatments (five replicates per treatment), consisting of formulated energy concentrations of 5.90 MJ/kg (high-energy diet, group H), 5.60 MJ/kg (medium-energy diet, group M) and 5.30 MJ/kg (low-energy diet, group L). The results showed that compared with group H, the expression of Claudin-1 in rumen epithelium of groups M and L was increased, but the expression of ZO-1 was decreased (p < 0.05). Moreover, compared with group H, group M down-regulated the expression of Occludin and Claudin-1 in the brain (p < 0.05). For rumen bacteria, the dominant phyla included Bacteroidetes and Firmicutes, the abundance of Actinobacteriota in groups M and L was significantly increased compared with group H (p < 0.05). At the genus level, the relative abundance of Corynebacterium, Eubacterium_nodatum_group and Neisseraceae in groups M and L was significantly decreased compared with group H (p < 0.05). For rumen fungi, the dominant phyla included Basidiomycota, Ascomycota and Neocariastigomycota, the relative abundance of Ascomycetes was significantly higher than that of groups M and L compared with group H (p < 0.05). At the genus level, the relative abundance of Neocelimastigaceae and Myceliophthora in groups M and L was significantly reduced compared with group H (p < 0.05). Furthermore, the expression of Claudin-1 in rumen epithelium was significantly positively correlated with Actinobacteriota, Corynebacterium and Neisseriaceae. The expression of ZO-1 in the spinal cord was significantly positively correlated with Myceliophthora. The expression of Occludin in brain was positively correlated with valerate content (p < 0.05). In summary, dietary energy levels affected the rumen microbiota of Honghe Yellow cattle. The expression of Claudin-1 in rumen epithelium and the total SCFAs concentration were increased with decreasing dietary energy levels, but the expression of Claudin-1 in brain and ZO-1 in the spinal cord were reduced with decreasing dietary energy levels. Meanwhile, the rumen microbiota and SCFAs were significantly correlated with the expression of TJP.

Novel Human Milk Fat Substitutes Based on Medium- and Long-Chain Triacylglycerol Regulate Thermogenesis, Lipid Metabolism, and Gut Microbiota Diversity in C57BL/6J Mice

Human milk is naturally rich in medium- and long-chain triacylglycerols (MLCT), accounting for approximately 30% of the total fat. However, infant formula fat is prepared using a physical blend of vegetable oils, which rarely contains MLCT, similar to human milk. The differences in MLCT between human milk and infant formulas may cause different lipid metabolisms and physiological effects on infants, which are unknown. This study aimed to analyze the metabolic characteristics of formula lipid containing novel human milk fat substitutes based on MLCT (FL-MLCT) and compare their effects with those of the physical blend of vegetable oils (FL-PB) on lipid metabolism and gut microbiota in mice. Compared with the FL-PB group, the FL-MLCT group showed increased energy expenditure, decreased serum triacylglycerol level, and significantly lower aspartate aminotransferase level, epididymal and perirenal fat weight, and adipocyte size. Moreover, the abundances of Firmicutes/Bacteroidota, Actinobacteriota, and Desulfovibrionaceae were significantly decreased in the FL-MLCT group. Novel human milk fat substitutes MLCT could inhibit visceral fat accumulation, improve liver function, and modulate the mice gut microbiota composition, which may contribute to controlling obesity.

Self-emulsifying drug delivery systems (SEDDS) disrupt the gut microbiota and trigger an intestinal inflammatory response in rats

Self-emulsifying drug delivery systems (i.e. SEDDS, SMEDDS and SNEDDS) are widely employed as solubility and bioavailability enhancing formulation strategies for poorly water-soluble drugs. Despite the capacity for SEDDS to effectively facilitate oral drug absorption, tolerability concerns exist due to the capacity for high concentrations of surfactants (typically present within SEDDS) to induce gastrointestinal toxicity and mucosal irritation. With new knowledge surrounding the role of the gut microbiota in modulating intestinal inflammation and mucosal injury, there is a clear need to determine the impact of SEDDS on the gut microbiota. The current study is the first of its kind to demonstrate the detrimental impact of SEDDS on the gut microbiota of Sprague-Dawley rats, following daily oral administration (100 mg/kg) for 21 days. SEDDS comprising a lipid phase (i.e. Type I, II and III formulations according to the Lipid Formulation Classification Scheme) induced significant changes to the composition and diversity of the gut microbiota, evidenced through a reduction in operational taxonomic units (OTUs) and alpha diversity (Shannon's index), along with statistically significant shifts in beta diversity (according to PERMANOVA of multi-dimensional Bray-Curtis plots). Key signatures of gut microbiota dysbiosis correlated with the increased expression of pro-inflammatory cytokines within the jejunum, while mucosal injury was characterised by significant reductions in plasma citrulline levels, a validated biomarker of enterocyte mass and mucosal barrier integrity. These findings have potential clinical ramifications for chronically administered drugs that are formulated with SEDDS and stresses the need for further studies that investigate dose-dependent effects of SEDDS on the gastrointestinal microenvironment in a clinical setting.

Glycerol monolaurate improved intestinal barrier, antioxidant capacity, inflammatory response and microbiota dysbiosis in large yellow croaker (Larimichthys crocea) fed with high soybean oil diets

Glycerol monolaurate (GML) is a potential candidate for regulating metabolic syndrome and inflammatory response. However, the role of GML in modulating intestinal health in fish has not been well determined. In this study, a 70-d feeding trial was conducted to evaluate the effect of GML on intestinal barrier, antioxidant capacity, inflammatory response and microbiota community of large yellow croaker (13.05 ± 0.09 g) fed with high level soybean oil (SO) diets. Two basic diets with fish oil (FO) or SO were formulated. Based on the SO group diet, three different levels of GML 0.02% (SO0.02), 0.04% (SO0.04) and 0.08% (SO0.08) were supplemented respectively. Results showed that intestinal villus height and perimeter ratio were increased in SO0.04 treatment compared with the SO group. The mRNA expressions of intestinal physical barrier-related gene odc and claudin-11 were significantly up-regulated in different addition of GML treatments compared with the SO group. Fish fed SO diet with 0.04% GML addition showed higher activities of acid phosphatase and lysozyme compared with the SO group. The content of malonaldehyde was significantly decreased and activities of catalase and superoxide dismutase were significantly increased in 0.02% and 0.04% GML groups compared with those in the SO group. The mRNA transcriptional levels of inflammatory response-related genes (il-1β, il-6, tnf-α and cox-2) in 0.04% GML treatment were notably lower than those in the SO group. Meanwhile, sequencing analysis of bacterial 16S rRNA V4-V5 region showed that GML addition changed gut microbiota structure and increased alpha diversity of large yellow croaker fed diets with a high level of SO. The correlation analysis results indicated that the change of intestinal microbiota relative abundance strongly correlated with intestinal health indexes. In conclusion, these results demonstrated that 0.02%-0.04% GML addition could improve intestinal morphology, physical barrier, antioxidant capacity, inflammatory response and microbiota dysbiosis of large yellow croaker fed diets with a high percentage of SO.

Supplementation with alpha-glycerol monolaurate during late gestation and lactation enhances sow performance, ameliorates milk composition, and improves growth of suckling piglets

BACKGROUND

Physiological changes during lactation cause oxidative stress in sows, reduce immunity, and hamper the growth capacity of piglets. Alpha-glycerol monolaurate (α-GML) has potential for enhancing the antimicrobial activity of sows and the growth of suckling piglets.

METHODS

Eighty sows were allocated randomly to four groups: basal diet and basal diets supplemented with 500, 1000, or 2000 mg/kg α-GML. The experiment started on d 85 of gestation and lasted until piglets were weaned on d 21 of lactation. The number of live-born piglets was standardized to 12 ± 1 per sow on day of parturition. On d 0 and 21 of lactation, body weight of piglets was measured and milk samples were obtained from sows, and serum samples and feces from piglets were obtained on d 21.

RESULTS

Feed intake, backfat loss, and weaning estrus interval did not differ among the four groups of sows. Maternal α-GML supplementation increased (P < 0.05) the body weight of piglets at weaning and the apparent total tract digestibility of crude fat of sows. The immunoglobulin A and immunoglobulin G levels were greater (P < 0.05) in a quadratic manner in the milk of sows as dietary α-GML increased. Concerning fatty acid profile, C12:0, C15:0, C17:0, C18:2n6c, C18:3n3, C24:0, and C22:6n3 were higher (P < 0.05) in linear and quadratic manners in colostrum of sows-fed α-GML diets compared with the control sows. There was lower (P < 0.05) n-6:n-3 polyunsaturated fatty acid ratio in milk than in the control sows. Maternal α-GML increased the abundance of Firmicutes (P < 0.05) and decreased the abundance of Proteobacteria (P < 0.05) of piglet fecal microbiota.

CONCLUSIONS

Dietary supplementation with α-GML improved milk immunoglobulins and altered fatty acids of sows, thereby improving the health of piglets.

Maternal supplementation with glycerol monolaurate improves the intestinal health of suckling piglets by inhibiting the NF-κB/MAPK pathways and improving oxidative stability

Glycerol monolaurate (GML) is a food safe emulsifier and a kind of MCFA monoglyceride that has been proven to confer positive benefits in improving animal health, production and feed digestibility as a feed additive. This study aims to evaluate whether supplementation of a sow diet with GML could affect the intestinal barrier function and antioxidant status of newborn piglets and to explore its regulatory mechanism. A total of 80 multiparous sows were divided into two groups, which were fed a basal diet or a basal diet supplemented with 0.1% GML. The results indicated that maternal supplementation with GML significantly increased fat, lactose and protein in sow colostrum, as well as fat and protein in sow 14-day milk (P < 0.05). The results showed that GML significantly reduced the concentrations of IL-12 in the duodenum, TNF-α, IL-1β and IL-12 in the jejunum, and IL-1β in the ileum of piglets (P < 0.05). Higher concentrations of T-AOC, T-SOD, GSH and GSH-Px and lower MDA in the intestine were observed in the GML group than in the control group. Correspondingly, the villi height, crypt depth and the ratio of villi height to crypt depth (V/C) in the jejunum and the V/C in the ileum in the GML group were significantly higher than those in the control group (P < 0.05). Moreover, the GML group displayed significantly increased protein abundance of zonula occludens (ZO)-1, occludin, and claudin-1 in the small intestine (P < 0.05), mRNA expression of mucins (MUCs) in the small intestine (MUC-1, MUC-3 and MUC-4), and mRNA expression of porcine beta defensins (pBDs) in the duodenum (pBD1 and pBD2), jejunum (pBD1, pBD2 and pBD129) (P < 0.05), and ileum (pBD2, pBD3 and pBD114) (P < 0.05). Further research showed that GML significantly reduced the phosphorylation of the NF-κB/MAPK pathways in the small intestine (P < 0.05). In addition, the results of 16S rDNA sequencing showed that maternal supplementation with GML altered the colonic microbiotic structure of piglets, and reduced the relative abundance of Escherichia shigella. In summary, a sow diet supplemented with GML enhanced the offspring's intestinal oxidative stability and barrier function and attenuated the offspring's intestinal inflammatory response, possibly by suppressing the activation of the NF-κB/MAPK pathways.

Effects of Plant-Derived Glycerol Monolaurate (GML) Additive on the Antioxidant Capacity, Anti-Inflammatory Ability, Muscle Nutritional Value, and Intestinal Flora of Hybrid Grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂)

In a context where the search for plant-derived additives is a hot topic, glycerol monolaurate (GML) was chosen as our subject to study its effect on grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂). Seven gradient levels of GML (0, 600, 1200, 1800, 2400, 3000, and 3600 mg/kg) were used for the experiment. Based on our experiments, 1800 mg/kg GML significantly increased the final body weight (FBW) and weight gain rate (WGR). GML increased the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreased malondialdehyde (MDA). Adding 1800 mg/kg GML also significantly increased the levels of lauric acid (C12:0) (LA), n-3 polyunsaturated fatty acids (PFA), and the n-6 PFA-to-n-3/n-6 ratio, while significantly decreasing the levels of saturated fatty acids (SFA). Dietary supplementation with GML significantly inhibited the expression of pro-inflammatory factors and reduced the occurrence of inflammation. GML improved intestinal flora and the abundance of beneficial bacteria (Bacillus, Psychrobacter, Acinetobacter, Acinetobacter, Stenotrophomonas, and Glutamicibacter). It provides a theoretical basis for the application of GML in aquafeed and greatly enhances the possibility of using GML in aquafeed. Based on the above experimental results, the optimum level of GML in grouper feed is 1800 mg/kg.

Effects of oral of administration of monoglycide laurate on virus load and inflammation in PEDV infected porcine

To investigate the effect of monoglyceryl laurate (GML) against PEDV in vivo, the clinical signs, pathological changes, tissue viral load and cytokine levels of piglets were compared in different GML treatment groups and PEDV infected group. The diets of experimental groups were supplemented with different doses of GML (5g for A1, 10g for A2, 20g for A3) on day 1, 2, and 3 after PEDV challenge, and the virus challenge group (group C) and blank group (group B) were set as control. The results showed that compared with group C, groups As could reduce the mortality rate of piglets, among which the protection rates of groups A2 and A3 could reach 100%. The trend of weight loss of piglets was effectively slowed down and growth performance recovered in GML treated groups. GML reduced the pathological damage of intestinal tract and the viral load in intestine and mesenteric lymph nodes. The levels of IL-8 and TNF-α in the blood of group As were inhibited by GML in a dose-dependent manner when compared with group C. Our study suggests that GML has potential anti-PEDV effects in vivo.

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.

Dietary Crude Protein Levels Alter Diarrhea Incidence, Immunity, and Intestinal Barrier Function of Huanjiang Mini-Pigs During Different Growth Stages

Huanjiang mini-pig is an indigenous pig breed in China; however, the optimal dietary crude protein (CP) levels for this pig breed during different growth stages has not been standardized yet. This study investigated the effects of different CP levels on diarrhea incidence, immunity, and intestinal barrier function in pigs. A total of 360 Huanjiang mini-pigs were assigned to three independent trials and fed the following CP diets: 5−10 kg stage, 14, 16, 18, 20, and 22%; 10−20 kg stage, 12, 14, 16, 18, and 20% and 20−30 kg stage, 10, 12, 14, 16, and 18%. In the 5−10 kg stage, the 22%; diet increased the plasma IL-1β, IL-6, IL-8, and TNF-α concentrations compared to the 14−20% diets and decreased IL-10 and TGF-β; however, these results were fluctuated in the later stages, including the decrease of IL-1β and IL-8 in the 20% group, TNF-α in the 18−20% groups, and the increase of IFN-γ in the 20% group at the 10−20 kg stage and the decrease of TNF-α in the 16% group at the 20−30 kg stage. The 20% diet increased the jejunal and ileal IL-10 concentration compared to the 14% diet at the 5−10 kg stage, as well as in the 16% diet compared to the 12% diet at the 10−20 kg stage. In addition, ileal IL-10 concentration was increased in the 16% diet compared to the 10, 12, and 18% diets at the 20−30 kg stage. Furthermore, the 18% diet at the 5−10 kg stage and the 16% diet at the 10−20 kg stage decreased jejunal IL-6 expression, whereas the 20% diet increased the TNF-α and IFN-γ at the 5−10 kg stage. The 20% diet increased the Claudin, Occludin, ZO-1, ZO-2, Mucin-1, and Mucin-20 expressions at the 5−10 kg stage, as well as TLR-2, TLR-4, and NF-κB in the 22 and 20% diets at the 5−10 and 10−20 kg stages, respectively. Collectively, these findings suggest optimal dietary CP levels of 16, 14, and 12% for Huanjiang mini-pigs during the 5−10, 10−20, and 20−30 kg growth stages, respectively; and provide the guiding significance of dietary CP levels for Huanjiang mini-pigs during different growth stages.

Effects of Medium-Chain Fatty Acid Glycerides on Nutrient Metabolism and Energy Utilization in Weaned Piglets

Weaning stress induces the depressed digestive and absorptive capacity and insufficient intestinal energy supply. Medium-chain fatty acid glycerides have shown to improve the growth performance and intestinal barrier function of weaned piglets in the previous study. This study was aimed to investigate the regulation of medium-chain fatty acid glyceride on the nutrient absorption and energy utilization of weaned piglets. Nighty healthy weaned piglets were randomly assigned into five treatments: NP (Normal protein, normal-protein diet no antibiotics included); NC (Negative control, low-protein diet no antibiotics included); PC (Positive control, low-protein diet +75 mg/kg quinocetone, 20 mg/kg virginiamycin and 50 mg/kg aureomycin); MCT (tricaprylin + tricaprin group, low-protein diet + tricaprylin + tricaprin); GML (glycerol monolaurate group, low-protein diet + glycerol monolaurate). The results showed that GML treatment increased the ALP activity, concentrations of serine and methionine, MCT treatment increased concentrations of serine and 3-methyl-histidine but decreased TG concentration in serum. MCT and GML supplementations significantly promoted the lipase activity in the jejunum and ileum, as well as the AMP content in the ileal mucosa. GML addition significantly decreased the contents of butyric acid, isobutyric acid and total volatile fatty acid. In addition, medium chain fatty acid glycerides altered gene expressions involved in lipid metabolism, which showing the increases of AMPK2, CD36 and CGI58 and the decreases of MGAT2 and DGAT2 in the liver, as well as the increases of CD36, CGI58, MGAT2 and DGAT2 in the subcutaneous adipose tissue. These findings showed that medium-chain fatty acid glyceride can effectively improve the absorption of nutrients and lipid metabolism of piglets to meet the energy demand of weaned piglets, and then regulate the growth and development of weaned piglets.

Effects of dietary glyceryl monolaurate supplementation on growth performance, non-specific immunity, antioxidant status and intestinal microflora of Chinese mitten crabs

This study aims to investigate the effects of glycerol monolaurate (GML) on growth performance, non-specific immunity, antioxidant capacity and intestinal microflora in Chinese mitten crabs. The crabs were randomly arranged to three experimental diets groups containing 0 (control group), 1000 mg/kg GML (GML1000 group), and 2000 mg/kg GML (GML2000 group), respectively. After 8 weeks of breeding, results showed a better growth performance in GML2000 group, with a higher PWG, SGR and lower FCR (P < 0.05). Meanwhile, in GML2000 group the activities of phenoloxidase, alkaline phosphatase, acid phosphatase and lysozyme in hemolymph were increased (P < 0.05), also the activities of hemolymph and hepatopancreas superoxide dismutase (SOD) and glutathione peroxidase (GPx) were increased in hepatopancreas (P < 0.05). While malondialdehyde (MDA) concentrations were lower significantly (P < 0.05) both in GML1000 and GML2000 groups. Furthermore, the mRNA expression of TLR1, TLR2, which related to the Toll pathway were increased (P < 0.05). Supplementation of 2000 mg/kg GML up-regulated the expression of ALF and LZM (P < 0.05), and down-regulated the expression of caspase-3 (P < 0.05). The abundance of Firmicutes increased in GML2000 group (P < 0.05), and Shewanella was significantly increased (P < 0.05) in both GML1000 and GML2000 groups. In conclusion, dietary supplemented with GML enhanced the growth performance and antioxidant capacity, enhanced hemolymph immune enzymes activities and antimicrobial peptides expression through regulating the proPO system and Toll pathway, and improved gut microflora in Chinese mitten crabs.

Medium chain triglycerides improve the growth performance, immune and antioxidant functions, and intestinal health of weaned rabbits

The purpose is to study the effects of different doses of medium chain triglyceride (MCT) on growth performance, immune and oxidative functions, and intestinal health of weaned rabbits. A total of 600 weaned rabbits weighing about 993.26 g and at 35 d of age were randomly divided into five groups. The control group was fed a basal diet containing 2400 mg/kg soybean oil, and the experimental group was substituted with 600, 1200, 1800, and 2400 mg/kg MCT. The whole trial period lasted for 48 d. The results showed that treatment with 2400 mg/kg MCT significantly increased the weaning survival rate and crude fat digestibility (p < 0.05) and dramatically raised the levels of serum immunoglobulin (Ig)A, IgG, IgM, catalase, superoxide dismutase, and total antioxidant capability (p < 0.05). The villus height and crypt depth in 1800 mg/kg MCT group were observably enhanced (p < 0.05). The abundance of Bacteroidetes was significantly increased in 1800 and 2400 mg/kg MCT groups (p < 0.05). In conclusion, 1800 and 2400 mg/kg MCT substituting soybean oil in the diet of weaned rabbits can improve the growth performance and intestinal barrier function of weaned rabbits.

The Effect of α-Monolaurin and Butyrate Supplementation on Broiler Performance and Gut Health in the Absence and Presence of the Antibiotic Growth Promoter Zinc Bacitracin

The use of antibiotic growth promoters (AGP) is common practice to improve broiler production and performance. The use of AGP is under discussion as it can induce bacterial resistance. The purpose of this study was to determine the impact of removing AGP from broiler feed and study the effect of feed additives. For those countries where in-feed AGP are still permitted, the effect of the products in the presence of AGP was evaluated. Half the number of male broilers received a diet free of AGP, whereas the other half received a diet supplemented with zinc bacitracin at 0.5 g/kg. Both diets were either without additional additives or combined with a coated sodium butyrate, α-monolaurin or a combination of these additives. Raised under optimal conditions, the incorporation of AGP had no effect on broiler performance, but negatively affected villi height and villi height to crypt depth (VH:CD) ratio in the duodenum. In the absence of AGP, butyric acid and α-monolaurin had a positive effect on villi height. In the presence of AGP, α-monolaurin resulted in the lowest feed conversion ratio and improved VH:CD ratio in the duodenum, jejunum and ileum. Both feed additives had minimal effect on performance parameters but showed small positive effects on gut health in the absence of AGP and could play a role in the strategy to replace AGP.