Dietary supplementation of Bacillus subtilis PB6 improves sow reproductive performance and reduces piglet birth intervals

We investigated the effects of dietary supplementation with Bacillus subtilis PB6 (B. subtilis PB6) during late gestation and lactation on sow reproductive performance, antioxidant indices, and gut microbiota. A total of 32 healthy Landrace × Yorkshire sows on d 90 of gestation were randomly assigned to 2 groups, with 16 replicates per group, receiving basal diet (CON) or the basal diet + 0.2% B. subtilis PB6, containing 4.0 × 10⁸ CFU/kg of feed (BS). The litter sizes (total born) and numbers of piglets born alive were larger in the BS group (P < 0.01), whereas the weights of piglets born alive and the piglet birth intervals were lower in the BS group (P < 0.05). Although the litter weights and piglet bodyweights (after cross-fostering) were lower after BS treatment (P < 0.05), the litter sizes, litter weights, lactation survival rate, and litter weight gains at weaning were higher in BS group (P < 0.05). The concentrations of malondialdehyde (MDA) in the sow sera at parturition were lower in the BS group (P < 0.01). The serum total antioxidant capacity (T-AOC) at parturition and the serum catalase (CAT) concentrations on d 21 of lactation were higher in the BS group (P < 0.05). Dietary supplementation with B. subtilis PB6 (P < 0.05) reduced the serum endotoxin concentrations in the sows and the serum cortisol concentrations of the piglets at d 14 of lactation. The α-diversity indices of microbial were higher in the CON group (P < 0.05). At the phylum level, B. subtilis PB6 supplementation increased the relative abundances of Gemmatimonadete and Acidobacteria (both P < 0.01) and reduced those of Proteobacteria, and Actinobacteria (both P < 0.05). At the genus level, B. subtilis PB6 supplementation increased the relative abundance of Ruminococcaceae_UCG-013 cc (P < 0.05) and reduced that of Streptococcus (P < 0.05). This study demonstrated that adding 4.0 × 10⁸ CFU/kg B. subtilis PB6 to sows’ feed during late gestation and lactation could shorten piglet birth intervals, enhance the growth performance of suckling piglets, and improve the gut health of sows during late gestation.     

Dietary fiber and microbiota interaction regulates sow metabolism and reproductive performance

Dietary fiber is a critical nutrient in sow diet and has attracted interest of animal nutritionists for many years. In addition to increase sows’ satiety, dietary fiber has been found to involve in the regulation of multiple biological functions in the sow production. The interaction of dietary fiber and gut microbes can produce bioactive metabolites, which are of great significance to sows'' metabolism and reproductive performance. This article reviewed the interaction between dietary fiber and gut microbes in regulating sows'' gut microbial diversity, intestinal immune system, lactation, and production performance, with the aim to provide a new strategy for the use of dietary fiber in sow diets.     

Mutual interaction between gut microbiota and protein/amino acid metabolism for host mucosal immunity and health

In recent years, many studies have shown that the intestinal microflora has various effects that are linked to the critical physiological functions and pathological systems of the host. The intestinal microbial community is widely involved in the metabolism of food components such as protein, which is one of the essential nutrients in diets. Additionally, dietary protein/amino acids have been shown to have had a profound impact on profile and operation of gut microbiota. This review summarizes the current literature on the mutual interaction between intestinal microbiota and protein/amino acid metabolism for host mucosal immunity and health.     

Swine gut microbiota and its interaction with host nutrient metabolism

Gut microbiota is generally recognized to play a crucial role in maintaining host health and metabolism. The correlation among gut microbiota, glycolipid metabolism, and metabolic diseases has been well reviewed in humans. However, the interplay between gut microbiota and host metabolism in swine remains incompletely understood. Given the limitation in conducting human experiments and the high similarity between swine and humans in terms of anatomy, physiology, polyphagy, habits, and metabolism and in terms of the composition of gut microbiota, there is a pressing need to summarize the knowledge gained regarding swine gut microbiota, its interplay with host metabolism, and the underlying mechanisms. This review aimed to outline the bidirectional regulation between gut microbiota and nutrient metabolism in swine and to emphasize the action mechanisms underlying the complex microbiome–host crosstalk via the gut microbiota–gut–brain axis. Moreover, it highlights the new advances in knowledge of the diurnal rhythmicity of gut microbiota. A better understanding of these aspects can not only shed light on healthy and efficient pork production but also promote our knowledge on the associations between gut microbiota and the microbiome–host crosstalk mechanism. More importantly, knowledge on microbiota, host health and metabolism facilitates the development of a precise intervention therapy targeting the gut microbiota.     

Trace metals and animal health: Interplay of the gut microbiota with iron,manganese, zinc,and copper

Metals such as iron, manganese, copper, and zinc are recognized as essential trace elements. These trace metals play critical roles in development, growth, and metabolism, participating in various metabolic processes by acting as cofactors of enzymes or providing structural support to proteins. Deficiency or toxicity of these metals can impact human and animal health, giving rise to a number of metabolic and neurological disorders. Proper breakdown, absorption, and elimination of these trace metals is a tightly regulated process that requires crosstalk between the host and these micronutrients. The gut is a complex system that serves as the interface between these components, but other factors that contribute to this delicate interaction are not well understood. The gut is home to trillions of microorganisms and microbial genes (the gut microbiome) that can regulate the metabolism and transport of micronutrients and contribute to the bioavailability of trace metals through their assimilation from food sources or by competing with the host. Furthermore, deficiency or toxicity of these metals can modulate the gut microenvironment, including microbiota, nutrient availability, stress, and immunity. Thus, understanding the role of the gut microbiota in the metabolism of manganese, iron, copper, and zinc, as well as in heavy metal deficiencies and toxicities, and vice versa, may provide insight into developing improved or alternative therapeutic strategies to address emerging health concerns. This review describes the current understanding of how the gut microbiome and trace metals interact and affect host health, particularly in pigs.     

Dietary supplemental xylooligosaccharide modulates nutrient digestibility,intestinal morphology,and gut microbiota in laying hens

This study was conducted to evaluate the prebiotic effects of dietary xylooligosaccharide (XOS) supplementation on performance, nutrient digestibility, intestinal morphology, and gut microbiota in laying hens. In a 12-wk experiment, a total of 288 Hy-Line Brown layers at 50 wk of age were randomly assigned into 3 dietary treatments supplemented with XOS at 0, 200 or 400 mg/kg. Each treatment had 8 replicates with 12 birds each. Hens fed XOS diets showed a lower feed-to-egg ratio during wk 7 to 12 and a higher egg yolk color value in wk 12 compared with those fed the control diet (P < 0.05). Dietary XOS supplementation improved the apparent total tract digestibility of gross energy and nitrogen at the end of the 12th wk (P < 0.05). In addition, a higher villus height-to-crypt depth ratio of the ileum was observed in XOS-added groups (P < 0.05). The high throughput sequencing analysis of bacterial 16S rRNA revealed that dietary XOS supplementation at 200 mg/kg altered cecal microbiota. Alpha diversity analysis illustrated a higher cecal bacterial richness in birds fed with XOS at 200 mg/kg. The composition of cecal microbiota modulated by the XOS addition was characterized by an increased abundance of Firmicutes along with a reduced abundance of Bacteroidetes. At the genus level, dietary XOS supplementation triggered decreases in Bacteroides and Campylobacter concurrent with increases in Lactobacillus and several short chain fatty acid producers including Desulfovibrio, Faecalitalea, Faecalicoccus, and 5 genera of family Lachnospiraceae. Collectively, dietary XOS addition improved the feed conversion ratio by modulating nutrient digestibility and ileal morphology in laying hens, which could be attributed to the enhancement of bacterial diversity and alteration of microbial composition.     

Flavor supplementation during late gestation and lactation periods increases the reproductive performance and alters fecal microbiota of the sows

This study was conducted to evaluate the effect of flavor on reproductive performance and fecal microbiota of sows during late gestation and lactation. A total of 20 healthy Yorkshire sows were fed a corn-soybean basal diet unsupplemented or supplemented with 0.1% flavor compound from d 90 of gestation to 25 d post-farrowing, and then the piglets were weaned. The reproductive performance and the fecal microbiota of sows were analyzed. Compared with the controls, flavor supplementation in maternal diets increased (P < 0.05) weaning litter weight, litter weight gain, weaning body weight, and average daily gain of piglets. There was a trend of increase in the average daily feed intake of sows (P = 0.09) by maternal dietary flavor addition. The backfat thickness and litter size were not affected by flavor supplementation (P > 0.05). The 16S rRNA analysis showed that flavor supplementation significantly increased the abundance of Phascolarctobacterium (P < 0.05), but significantly decreased genera Terrisporobacter, Alloprevotella, Clostridium_sensu_stricto_1, and Escherichia-shigella (P < 0.05). Spearman correlation analysis showed that Phascolarctobacterum was positively correlated with the average daily feed intake of sows (P < 0.05), the litter weight gain and average daily gain of piglets (P < 0.05). In contrast, Clostridium_sensu_stricto_1 and unclassified_f__Lachnospiraceae were negatively correlated with the litter weight gain and average daily gain of piglets (P < 0.05). Taken together, dietary flavor supplementation improved the reproductive performance of the sows, which was associated with enhanced beneficial microbiota and decreased potentially pathogenic bacteria in the sows.     

Effect of susceptibility to enterotoxigenic Escherichia coli F4 and of dietary tryptophan on gut microbiota diversity observed in healthy young pigs

Healthy weaned pigs susceptible to enterotoxigenic Escherichia coli F4 (ETEC) require more tryptophan (Trp) to maximize their performance. This may be related to an effect on intestinal microbiota. We studied the intestinal bacterial diversity of healthy pigs with different susceptibility to ETEC and fed different Trp levels. Thirty-six littermate weaned pigs were selected to obtain a set potentially formed of 50% ETEC-susceptible and 50% non-susceptible pigs, based on a Mucin 4 gene polymorphism. Pigs were fed a diet with 0.17 (TrpL) or 0.22 (TrpH) standardized ileal digestible Trp:Lys ratio for 21 days. Slaughtered pigs were classified into non-susceptible, mildly susceptible, and susceptible, by testing ETEC adhesion to intestinal villi. Bacterial diversity in jejunum content was assessed by the 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) fingerprinting analysis and expressed by the Shannon index. Susceptible pigs had a reduced bacterial diversity, particularly with TrpL diet (p = 0.003). The ETEC adhesion class affected the quantification of enterobacteria DNA (p = 0.027). One DGGE band, which referred to Clostridium bartlettii, was not evidenced in all the susceptible pigs; less DNA from this microbe was quantified by RT-PCR in the jejunum from TrpH susceptible pigs (p = 0.025) compared to TrpL. The gene expression for β-galactoside α-2,3-sialyltransferase 1 was higher in jejunal tissue of ETEC-susceptible pigs (p = 0.019). In studies on pig gut microbiota, the presence of intestinal receptors for ETEC should be considered because of their contribution to a reduced bacterial diversity. This effect could be partially reversed by dietary Trp addition.     

大豆异黄酮对坝上长尾鸡卵巢功能、生殖激素和肌肉品质的影响

本试验旨在研究大豆异黄酮对坝上长尾鸡卵巢功能、生殖激素和肌肉品质的影响。试验采用单因子试验设计,选取150只坝上长尾鸡(公母各半),随机分为5组,每组3个重复,每个重复10只鸡。Ⅰ~Ⅴ试验组分别在基础日粮中添加5,10,15,20,25 mg/kg剂量的大豆异黄酮。结果显示,卵巢功能各指标在数值上会随着大豆异黄酮添加量的升高表现出先上升后下降的过程。LH:Ⅲ组最高,与Ⅰ组、Ⅴ组差异显著(P<0.05),与Ⅱ组、Ⅳ组差异不显著(P>0.05);FSH:Ⅲ组与高剂量组差异不显著(P>0.05),与低剂量差异显著(P<0.05);E2:Ⅲ组最高,与Ⅰ组差异显著(P<0.05),比Ⅰ组高3.19%;PRL:Ⅲ组最高,与高剂量组和低剂量组差异都不显著(P>0.05);P4:Ⅲ组最高,与Ⅳ组差异不显著(P>0.05)。红度a*:Ⅲ组比Ⅰ组和Ⅴ组显著提高11.12%和9.08%(P<0.05);肌肉pH:Ⅲ组显著低于Ⅰ组和Ⅴ组,分别降低3.81%和2.14%(P<0.05);肌肉系水力:Ⅲ组显著高于Ⅰ组11.9%(P<0.05);剪切力:Ⅲ组显著低于其他剂量组(P<0.05);组织学性状:肌纤维密度Ⅱ组与Ⅲ组显著高于Ⅰ组、Ⅳ组和Ⅴ组(P<0.05),Ⅲ组比Ⅳ组、Ⅴ组分别提高29.20%和36.23%;肌肉风味方面,各试验组间氨基酸差异不显著(P>0.05)。结果表明,适宜的大豆异黄酮(15 mg/kg)能较好地提高坝上长尾鸡卵巢功能、生殖激素水平和肌肉品质。     

Adaptation of gut microbiota to corn physical structure and different types of dietary fibre

An experiment was designed to study the effect of corn physical structure and different types of dietary fibre on pig gut microbiota during growing. Ninety-six animals (15 ± 2.2 kg) were assigned to four different diets: a control diet (CT), a diet with coarse ground corn (CC), and other two with 8% of sugar beet pulp (BP) or 10% of wheat bran (WB). Thirty-two animals (8 per diet) were sacrificed on days 7, 21 and 42 to measure microbial activity in digesta. Other 8 pigs were sacrificed on day 0 before receiving the diets. Enterobacteria and lactobacilli population in colon were quantified by qPCR. With all diets enterobacteria diminished with time and were lower than lactobacilli. Expressed as lactobacilli:enterobacteria ratio we found differences between diets at day 7 and 21 that had disappeared at day 42. Purine bases (PB) concentration indicated an adaptation of the microbiota with time which was reflected in an increasing content in the caecum and a decreasing content in the colon. Time of adaptation of microbiota was also shown by xylanase and cellulase activities that were not detected until day 7 and 42, respectively. Results obtained shows that pig gut microbiota need a relative long time to adapt after a change of diet that could last up to 6 weeks. We were not able to detect a clear effect of dietary fibre content on this process.     

Isomaltooligosaccharide and Bacillus regulate the duration of farrowing and weaning-estrous interval in sows during the perinatal period by changing the gut microbiota of sows

This study investigated the effects of isomaltooligosaccharide (IMO) and Bacillus in perinatal diets on the duration of farrowing and post-weaning estrus, serum reproductive hormone concentrations, and gut microbiota and its metabolites of sows. Multiparous sows (n = 130) were fed diets without IMO (control, CON group), or diets containing only IMO (IMO group), IMO and Bacillus subtilis (IMOS group), IMO and Bacillus licheniformis (IMOL group), and IMO and B. subtilis and B. licheniformis (IMOSL group), respectively. The results indicate that the duration of farrowing and post-weaning estrus was shorter in sows in the IMOS, IMOL, and IMOSL groups, and the weaning-estrous interval was lower in sows in the IMOL greoup. In addition, the lowest fecal score was observed in the IMOL group during d 106 to 112 of gestation. Sows in most of the treatment groups had a higher concentration of serum prolactin and prostaglandin at farrowing, but a lower serum concentration of estradiol, oxytocin, and progesterone on d 18 of lactation than sows in the CON group. The treatment groups had a higher abundance of Candidatus Methanoplasma and Bacillus and a lower abundance of Escherichia-Shigella in their feces at farrowing. Furthermore, the treatment groups had higher concentrations of total short-chain fatty acids (SCFA) in feces at farrowing and a higher concentration of branched fatty acids in feces on d 18 of lactation. Furthermore, the abundance of Bacillus in feces was positively correlated with serum prostaglandin concentrations and fecal total SCFA of sows at farrowing, but was negatively correlated with the duration of farrowing. Overall, dietary IMO and Bacillus supplementation affected the concentration of serum reproductive hormones and the duration of farrowing and post-weaning estrus, and the gut microbiota is a key factor.     

Association between the body weight of growing pigs and the functional capacity of their gut microbiota

Gastrointestinal microbiota impact host's biological activities, including digestion of indigestible feed components, energy harvest, and immunity. In this study, fecal microbiota of high body weight (HW) and low body weight (LW) growing pigs at 103 days of age were compared. Principal coordinates analysis separated the HW and LW groups into two clusters, indicating their potential differences between microbial community composition. Although the abundances of two major phyla, Firmicutes and Bacteroidetes, did not significantly differ between the HW and LW groups, some genera showed significant differences. Among them, Peptococcus and Eubacterium exhibited strong positive correlations with body weight (BW) and average daily gain (ADG) (Rho > 0.40), whereas Treponema, Desulfovibrio, Parabacteroides, and Ruminococcaceae_unclassified exhibited strong negative correlations with BW and ADG (Rho < ?0.40). Based on these results, the structure of intestinal microbiota may affect growth traits in pigs through host–microbe interactions. Further in‐depth studies will provide insights into how best to reshape host–microbe interactions in pigs and other animals as well.     

Dietary copper/zinc-loaded montmorillonite improved growth performance and intestinal barrier and changed gut microbiota in weaned piglets

The effects of copper/zinc-loaded montmorillonite (Cu/Zn-Mt) on growth performance, intestinal barrier and gut microbiota of weaned pigs were investigated in the present study. A total of 108 piglets (Duroc × Landrace × Yorkshire; 6.36 kg; weaned at 21 ± 1 d age) were used in this experiment. The pigs were randomly assigned to three treatments with six replicates, six pigs in each replicate. The three treatments were as follows: (1) control group: basal diet; (2) Cu/Zn-Mt group: basal diet supplemented with 39 mg/kg Cu and 75 mg/kg Zn as Cu/Zn-Mt; and (3) Cu +Zn +Mt group: basal diet supplemented with the mixture of copper sulphate, zinc sulphate and montmorillonite (equivalent to the copper and zinc in the Cu/Zn-Mt treatment). The results indicated that, compared with the pigs from control group, average daily gain and gain: feed ratio were increased and the faecal score on days 7 and 14 after weaning was decreased by supplementation of Cu/Zn-Mt; intestinal transepithelial electrical resistance (TER) and expressions of tight junction protein claudin-1 and zonula occludens-1 were increased, and intestinal permeability of fluorescein isothiocyanate-dextran 4 kDa was decreased by supplementation with Cu/Zn-Mt. According to the Illumina-based sequencing results, Cu/Zn-Mt supplementation increased the relative abundance of core bacteria (Lactococcus, Bacillus) at genus level and decreased the potentially pathogenic bacteria (Streptococcus and Pseudomonas) in colon of weaned piglets. However, the piglets fed with the mixture of copper sulphate, zinc sulphate and montmorillonite showed no effects in above parameters in comparison with the pigs from control group. In conclusion, dietary Cu/Zn-Mt could improve growth performance, decrease the diarrhoea and improve intestinal barrier and bacterial communities of weaned pigs. The results indicated that ‘loading’ of montmorillonite with Zn and Cu changed not only its chemical but also its nutritional properties.     

Effects of Bacillus pumilus on growth performance,immunological indicators and gut microbiota of mice

An increasing number of Bacillus strains have been developed for use as animal feed additives. The aim of the current work was to evaluate the impacts of Bacillus pumilus fsznc-09 in growth performance, organs development, blood constituents, genes expression of growth and immune in spleen and microbial communities in jejunum of weanling mice. The results showed that the body weight of mice in BP1 group increased significantly (p < 0.05) after feeding Bacillus pumilus fsznc-09. Compared with control group, the feed conversion ratio of BP1 and BP2 groups showed 13.57% (p < 0.05) and 9.64% improvements, respectively. The lengths of large intestine, small intestine in BP1 group were significantly increased (p < 0.05). While compared with control group, the organ indexes in BP1 and BP2 group did not differ significantly. Compared with control group, the activities of serum total superoxide dismutase (T-SOD), alkaline phosphatase (AKP), lysozyme (LZM) in BP1 group and T-SOD, AKP in BP2 group were significantly increased (p < 0.05). Compared with control group, the expressions of ghrelin-2 (Ghrl-2) and insulin-like growth factor 1 (Igf1) in BP1 group were significantly increased (p < 0.05). Compared with control group, the expressions of interleukin-6 (IL-6), nitric oxide synthase (INOS), tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β) in BP1 group and the expressions of IL-6, INOS, TNF-α, IL-1β and interferon alpha 11 (Ifna11) in BP2 group were slightly decreased. Moreover, compared with control group, the diversity of intestinal flora and relative abundance of potentially probiotics (e.g., Bifidobacterium, Bacillus) in BP1 and BP2 groups were increased. While compared with control group, the relative abundance of the potentially pathogenic bacterium (e.g., Staphylococcus) was reduced. The relative abundances of dominant species in BP1 (Lactobacillus johnsonii) and BP2 (Lactobacillus reuteri) groups were also higher than control group (Lactobacillus intestinalis). In conclusion, Bacillus pumilus fsznc-09 might improve the growth performance and immunity of mice.     

Dietary ferulic acid and vanillic acid on inflammation,gut barrier function and growth performance in lipopolysaccharide-challenged piglets

Ferulic acid(FA) and vanillic acid(VA) are considered as major phenolic metabolites of cyanidin 3-glucoside, a polyphenol that widely exists in plants that possess a protective effect against oxidative stress and inflammation in our previous study. This study aimed to investigate the effect of FA and VA on inflammation, gut barrier function, and growth performance in a weaned piglet model challenged with lipopolysaccharide(LPS). Thirty-six piglets(PIC 337 × C48, 28 d of age) were randomly alloca...     

Dietary fatty acids in gut health: Absorption,metabolism and function

In biological responses, fatty acids (FA) are absorbed and metabolized in the form of substrates for energy production. The molecular structures (number of double bonds and chain length) and composition of dietary FA impact digestion, absorption and metabolism, and the biological roles of FA. Recently, increasing evidence indicates that FA are essentially utilized as an energy source and are signaling molecules that exert physiological activity of gut microbiota and immune responses. In addition, FA could serve as natural ligands for orphan G protein-coupled receptors (GPCR), also called free fatty acid receptors (FFAR), which intertwine metabolic and immune systems via multiple mechanisms. The present review explores the recent findings on FA absorption and its impact on gut health, particularly addressing the mechanism by which dietary FA potentially influences intestinal microbiota and epithelial functions. Also, this work attempts to uncover research ideas for devising future strategies for manipulating the composition of dietary FA to regulate gut health and support a normal immune system for metabolic and immune disorders.     

大豆黄酮对肉仔鸡内分泌激素与免疫机能的影响

选用240只1日龄艾维菌肉鸡,分别随机分为四个组,对照组饲喂基础日粮,试验组在基础日粮中分别添加5 mg/kg、10 mg/kg、15 mg/kg大豆黄酮。研究结果表明:(1)日粮添加大豆黄酮对肉公鸡免疫器官重量有增加的趋势,但差异不显著(P>0.05),(2)添加大豆黄酮仅49日龄公鸡T淋巴细胞ANAE阳性率差异显著,而其余差异均不显著(P>0.05);(3)添加大豆黄酮对肉用母鸡血清尿素氮含量影响不大,而公鸡血清尿素氮水平均显著降低,(4)添加大豆黄酮对肉用公鸡血清GH、IGF-1、睾酮匀有显著影响,而对母鸡血清GH、IGF-1无显著影响。     

Genetic relationships between efficiency traits and gut microbiota traits in growing pigs being fed with a conventional or a high-fiber diet

In pigs, the gut microbiota composition plays a major role in the process of digestion, but is influenced by many external factors, especially diet. To be used in breeding applications, genotype by diet interactions on microbiota composition have to be quantified, as well as their impact on genetic covariances with feed efficiency (FE) and digestive efficiency (DE) traits. This study aimed at determining the impact of an alternative diet on variance components of microbiota traits (genera and alpha diversity indices) and estimating genetic correlations between microbiota and efficiency traits for pigs fed a conventional (CO) or a high-fiber (HF) diet. Fecal microbes of 812 full-siblings fed a CO diet and 752 pigs fed the HF diet were characterized at 16 weeks of age by sequencing the V3-V4 region of the 16S rRNA gene. A total of 231 genera were identified. Digestibility coefficients of nitrogen, organic matter, and energy were predicted analyzing the same fecal samples with near infrared spectrometry. Daily feed intake, feed conversion ratio, residual feed intake and average daily gain (ADG) were also recorded. The 71 genera present in more than 20% of individuals were retained for genetic analyses. Heritability (h²) of microbiota traits were similar between diets (from null to 0.38 ± 0.12 in the CO diet and to 0.39 ± 0.12 in the HF diet). Only three out of the 24 genera and two alpha diversity indices with significant h² in both diets had genetic correlations across diets significantly different from 0.99 (P < 0.05), indicating limited genetic by diet interactions for these traits. When both diets were analyzed jointly, 59 genera had h² significantly different from zero. Based on the genetic correlations between these genera and ADG, FE, and DE traits, three groups of genera could be identified. A group of 29 genera had abundances favorably correlated with DE and FE traits, 14 genera were unfavorably correlated with DE traits, and the last group of 16 genera had abundances with correlations close to zero with production traits. However, genera abundances favorably correlated with DE and FE traits were unfavorably correlated with ADG, and vice versa. Alpha diversity indices had correlation patterns similar to the first group. In the end, genetic by diet interactions on gut microbiota composition of growing pigs were limited in this study. Based on this study, microbiota-based traits could be used as proxies to improve FE and DE in growing pigs.     

Effects of Lactobacillus plantarum on the intestinal morphology,intestinal barrier function and microbiota composition of suckling piglets

This study investigated the effect of Lactobacillus plantarum strain 299v on gut health in suckling piglets. Sixty newborn piglets were assigned to control and probiotic treatments, with three litters per treatment (ten piglets/litter). From days 1 to 20 of life, piglets were orally administered a placebo of 0.1% peptone or 1.0 ×  10¹⁰ CFU L. plantarum 299v daily. Six piglets per treatment were sacrificed on day 20, and intestinal tissues (including duodenum, jejunum, ileum and colon) and the intestinal contents from colon segments were collected. The results demonstrated that piglets treated with L. plantarum 299v had a lower diarrhoea incidence than the controls. L. plantarum 299v administration significantly increased the ratio of the villus height to the crypt depth in the jejunum and ileum, as well as the mRNA expression of jejunal occludin and ileal zonula occludens 1 (ZO‐1). The L. plantarum treatment also increased the mRNA abundance of porcine β‐defensin 2 (pBD2) and pBD3 in the jejunum and ileum and of toll‐like receptors (TLRs), such as TLR2, TLR4, TLR6 and TLR9 in the ileum, and significantly upregulated the mRNA abundances of ileal pBD1 and colonic TLR4. Additionally, the L. plantarum 299v treatment significantly changed the structure of the colonic microbiota, as evidenced by the obvious increases in the relative abundances of the phyla Firmicutes and Actinobacteria and of the genus Lactobacillus. Our findings indicate that L. plantarum 299v facilitates the gut health of suckling piglets, probably by improving the intestinal morphology and intestinal barrier function and by modifying the structure of the gut microbiota.     

Gut microbiota absence and transplantation affect growth and intestinal functions: An investigation in a germ-free pig model

This study was conducted to investigate host–microbiota interactions and explore the effects of maternal gut microbiota transplantation on the growth and intestinal functions of newborns in a germ-free (GF) pig model. Twelve hysterectomy-derived GF Bama piglets were reared in 6 sterile isolators. Among them, 6 were considered as the GF group, and the other 6 were orally inoculated with healthy sow fecal suspension as fecal microbiota transplanted (FMT) group. Another 6 piglets from natural birth were regarded as the conventional (CV) group. The GF and FMT groups were hand-fed with Co60-γ-irradiated sterile milk powder, while the CV group was reared by lactating Bama sows. All groups were fed for 21 days. Then, all piglets and then were switched to sterile feed for another 21 days. Results showed that the growth performance, nutrient digestibility, and concentrations of short-chain fatty acids in the GF group decreased (P < 0.05). Meanwhile, the serum urea nitrogen concentration and digesta pH values in the GF group increased compared with those in the FMT and CV groups (P < 0.05). Compared with the CV group, the GF group demonstrated upregulation in the mRNA expression levels of intestinal barrier function-related genes in the small intestine (P < 0.05). In addition, the mRNA abundances of intestinal development and absorption-related genes in the small intestine and colon were higher in the GF group than in the CV and FMT groups (P < 0.05). The FMT group exhibited greater growth performance, lipase activity, and nutrient digestibility (P < 0.05), higher mRNA expression levels of intestinal development and barrier-related genes in the small intestine (P < 0.05), and lower mRNA abundances of pro-inflammatory factor in the colon and jejunum (P < 0.05) than the CV group. In conclusion, the absence of gut microbes impaired the growth and nutrient digestibility, and healthy sow gut microbiota transplantation increased the growth and nutrient digestibility and improved the intestinal development and barrier function of newborn piglets, indicating the importance of intestinal microbes for intestinal development and functions.