Effect of different dosage of sodium butyrate and niacin on growth, fecal microbiota and vitamin B metabolism in weaned piglets

Heat-Killed Lactobacillus acidophilus Promotes Growth by Modulating the Gut Microbiota Composition and Fecal Metabolites of Piglets

Probiotics can improve animal growth performance and intestinal health. However, understanding the effects of paraprobiotics on the growth performance and gut microbiota of piglets and how the paraprobiotics exert their impact are still limited. The present study was conducted to investigate the effects of heat-killed Lactobacillus acidophilus IFFI 6005 supplementation on the growth performance, intestinal microbiota, and fecal metabolites of piglets. First, a feed-additive sample of heat-killed Lactobacillus acidophilus IFFI 6005 was prepared by culture. Second, 96 (initial BW = 14.38 ± 0.67 kg, weaning age of 40 days) healthy piglets were selected and randomized into four treatment groups. Each treatment group consisted of three replicates (n = 8). Pigs were fed a basal diet (NC), basal diet plus antibiotics (PC), basal diet plus Lactobacillus acidophilus IFFI 6005 at 600 g/t (LA, 1.0 × 1010 cfu/g), and basal diet plus heat-killed Lactobacillus acidophilus IFFI 6005 at 600 g/t (HKLA), respectively; the trial lasted for 30 days. The results showed that the ratios of feed to gain (F:G) and diarrhea rate of both the HKLA and PC groups were significantly lower compared with the NC and LA groups (p < 0.05); however, there was no significant difference between the HKLA and PC group (p > 0.05). In addition, the average daily weight gain (ADG) of the HKLA group was significantly higher (p < 0.05) than that of the other three groups in terms of growth performance. Finally, 16S rRNA sequencing and metabolome analysis based on fecal samples further elaborated that the addition of heat-killed Lactobacillus acidophilus IFFI 6005 to the feed improved the intestinal microbial diversity and abundance (p < 0.05) and reduced the abundance of pathogenic bacteria (p < 0.05), but it did not affect the abundance of Lactobacillus (p > 0.05). Through the comparison of microbial abundance and metabolite content between the two groups (NC_vs_HKLA), the largest differences were found in six microorganisms and 10 metabolites in the intestine (p < 0.05). These differential metabolites were involved in the digestion, absorption and utilization of protein and starch, as well as in oxidative stress. In summary, addition of heat-killed Lactobacillus acidophilus IFFI 6005 as a new feed additive in piglets has beneficial effects on the growth performance, intestinal bacteria and metabolites, and can be used as an alternative to antibiotics.

Microbiota-Induced Epigenetic Alterations in Depressive Disorders Are Targets for Nutritional and Probiotic Therapies

Major depressive disorder (MDD) is a complex disorder and a leading cause of disability in 280 million people worldwide. Many environmental factors, such as microbes, drugs, and diet, are involved in the pathogenesis of depressive disorders. However, the underlying mechanisms of depression are complex and include the interaction of genetics with epigenetics and the host immune system. Modifications of the gut microbiome and its metabolites influence stress-related responses and social behavior in patients with depressive disorders by modulating the maturation of immune cells and neurogenesis in the brain mediated by epigenetic modifications. Here, we discuss the potential roles of a leaky gut in the development of depressive disorders via changes in gut microbiota-derived metabolites with epigenetic effects. Next, we will deliberate how altering the gut microbiome composition contributes to the development of depressive disorders via epigenetic alterations. In particular, we focus on how microbiota-derived metabolites such as butyrate as an epigenetic modifier, probiotics, maternal diet, polyphenols, drugs (e.g., antipsychotics, antidepressants, and antibiotics), and fecal microbiota transplantation could positively alleviate depressive-like behaviors by modulating the epigenetic landscape. Finally, we will discuss challenges associated with recent therapeutic approaches for depressive disorders via microbiome-related epigenetic shifts, as well as opportunities to tackle such problems.

Effects of sodium butyrate on growth performance, antioxidant status, inflammatory response and resistance to hypoxic stress in juvenile largemouth bass (Micropterus salmoides)

The aim of this study was to investigate the effects of sodium butyrate (SB) supplementation on growth performance, antioxidant enzyme activities, inflammatory factors, and hypoxic stress in largemouth bass (Micropterus salmoides). Diets were supplemented with different doses of SB at 0 (SB0), 0.5 (SB1), 1.0 (SB2) and 2.0 (SB3) g/kg. The hypoxic stress experiment was performed after 56 days of culture. The results showed that compared with the SB0 group, the final body weight, weight gain rate and protein deposition rate of the SB3 group were significantly increased (P<0.05), while FCR was significantly decreased (P<0.05). The contents of dry matter, crude lipids, and ash in the SB2 group were significantly higher than those in the SB0 group (P<0.05). The urea level was significantly decreased (P<0.05), and the glucose content was significantly increased (P<0.05) in the SB supplement group. Compared with the SB0 group, the SB2 group had significant reductions in the levels of serum triglyceride, cholesterol, elevated-density lipoprotein cholesterol, and low-density lipoprotein (P<0.05), and significant reductions in the levels of liver alkaline phosphatase and malondialdehyde (P<0.05). The total antioxidant capacity of the SB1 group was higher than that of other groups (P<0.05). Compared with the SB0 group, the mRNA expression of TLR22, MyD88, TGF-β1, IL-1β and IL-8 in the SB2 group significantly decreased (P<0.05). The cumulative mortality rate was significantly decreased in the SB2 and SB3 groups in comparison with that in the SB0 group after three hours of hypoxic stress (P<0.05). In a 56-day feeding trial, SB enhanced largemouth bass growth by increasing antioxidant enzyme activity and inhibiting TLR22-MyD88 signaling, therefore increasing cumulative mortality from hypoxic stress in largemouth bass.

Genetic- and Fiber-Diet-Mediated Changes in Antibiotic Resistance Genes in Pig Colon Contents and Feces and Their Driving Factors

Comprehensive studies on the effects of genetics and fiber diets on antibiotic resistance genes (ARGs) remain scarce. In this study, we analyzed the profiles of ARGs in colonic contents and fecal samples of Taoyuan, Duroc, and Xiangcun pigs (n = 10) fed at different fiber levels. Through macrogenomic analysis, we identified a total of 850 unique types of ARGs and classified them into 111 drug resistance classes. The abundance of partially drug-resistant ARGs was higher in the colonic contents of local pig breeds under a large-scale farming model. ARGs were found to be widely distributed among a variety of bacteria, predominantly in the phyla Firmicutes, Proteobacteria, and Bacteroidetes. Fiber diets reduce the abundance of ARGs in colonic contents and feces, and mobile genetic elements (MGEs) and short-chain fatty acids (SCFAs) are important drivers in mediating the effect of fiber diets on the abundance of ARGs. In vitro fermentation experiments confirmed that butyric acid significantly reduced the abundance of ARGs. In summary, the results of this study enhanced our understanding of the distribution and composition of ARGs in the colon of different breeds of pigs and revealed that a fiber diet can reduce ARGs in feces through its Butyric acid, providing reference data for environmental safety.

Employing pigs to decipher the host genetic effect on gut microbiome: advantages, challenges, and perspectives

The gut microbiota is a complex and diverse ecosystem comprised of trillions of microbes and plays an essential role in host's immunity, metabolism, and even behaviors. Environmental and host factors drive the huge variations in the gut microbiome among individuals. Here, we summarize accumulated evidences about host genetic effect on the gut microbial compositions with emphases on the correlation between host genetic kinship and the similarity of microbial compositions, heritability estimates of microbial taxa, and identification of genomic variants associated with the gut microbiome in pigs as well as in humans. A proportion of bacterial taxa have been reported to be heritable, and numerous variants associated with the diversity of the gut microbiota or specific taxa have been identified in both humans and pigs. LCT and ABO gene have been replicated in multiple studies, and its mechanism have been elucidated clearly. We also discuss the main advantages and challenges using pigs as experimental animals in exploring host genetic effect on the gut microbial composition and provided our insights on the perspectives in this area.

Impacts of Dietary Protein and Niacin Deficiency on Reproduction Performance, Body Growth, and Gut Microbiota of Female Hamsters (Tscherskia triton) and Their Offspring

Food resources are vital for animals to survive, and gut microbiota play an essential role in transferring nutritional materials into functional metabolites for hosts. Although the fact that diet affects host microbiota is well known, its impacts on offspring remain unclear. In this study, we assessed the effects of low-protein and niacin-deficient diets on reproduction performance, body growth, and gut microbiota of greater long-tailed hamsters (Tscherskia triton) under laboratory conditions. We found that maternal low-protein diet (not niacin deficiency) had a significant negative effect on reproduction performance of female hamsters (longer mating latency with males and smaller litter size) and body growth (lower body weight) of both female hamsters and their offspring. Both protein- and niacin-deficient diets showed significant maternal effects on the microbial community in the offspring. A maternal low-protein diet (not niacin deficiency) significantly reduced the abundance of major bacterial taxa producing short-chain fatty acids, increased the abundance of probiotic taxa, and altered microbial function in the offspring. The negative effects of maternal nutritional deficiency on gut microbiota are more pronounced in the protein group than the niacin group and in offspring more than in female hamsters. Our results suggest that a low-protein diet could alter gut microbiota in animals, which may result in negative impacts on their fitness. It is necessary to conduct further analysis to reveal the roles of nutrition, as well as its interaction with gut microbes, in affecting fitness of greater long-tailed hamsters under field conditions. IMPORTANCE Gut microbes are known to be essential for hosts to digest food and absorb nutrients. Currently, it is still unclear how maternal nutrient deficiency affects the fitness of animals by its effect on gut microbes. Here, we evaluated the effects of protein- and niacin-deficient diets on mating behavior, reproduction, body growth, and gut microbiota of both mothers and offspring of the greater long-tailed hamster (Tscherskia triton) under laboratory conditions. We found that a low-protein diet significantly reduced maternal reproduction performance and body growth of both mothers and their offspring. Both protein and niacin deficiencies showed significant maternal effects on the microbial community of the offspring. Our results hint that nutritional deficiency may be a potential factor in causing the observed sustained population decline of the greater long-tailed hamsters due to intensified monoculture in the North China Plain, and this needs further field investigation.

Niacin Improves Intestinal Health through Up-Regulation of AQPs Expression Induced by GPR109A

(1) Background: Changes in the expression of aquaporins (AQPs) in the intestine are proved to be associated with the attenuation of diarrhea. Diarrhea is a severe problem for postweaning piglets. Therefore, this study aimed to investigate whether niacin could alleviate diarrhea in weaned piglets by regulating AQPs expression and the underlying mechanisms; (2) Methods: 72 weaned piglets (Duroc × (Landrace × Yorkshire), 21 d old, 6.60 ± 0.05 kg) were randomly allotted into 3 groups for a 14-day feeding trial. Each treatment group included 6 replicate pens and each pen included 4 barrows (n = 24/treatment). Piglets were fed a basal diet (CON), a basal diet supplemented with 20.4 mg niacin/kg diet (NA) or the basal diet administered an antagonist for the GPR109A receptor (MPN). Additionally, an established porcine intestinal epithelial cell line (IPEC-J2) was used to investigate the protective effects and underlying mechanism of niacin on AQPs expression after Escherichia coli K88 (ETEC K88) treatment; (3) Results: Piglets fed niacin-supplemented diet had significantly decreased diarrhea rate, and increased mRNA and protein level of ZO-1, AQP 1 and AQP 3 in the colon compared with those administered a fed diet supplemented with an antagonist (p < 0.05). In addition, ETEC K88 treatment significantly reduced the cell viability, cell migration, and mRNA and protein expression of AQP1, AQP3, AQP7, AQP9, AQP11, and GPR109A in IPEC-J2 cells (p < 0.05). However, supplementation with niacin significantly prevented the ETEC K88-induced decline in the cell viability, cell migration, and the expression level of AQPs mRNA and protein in IPEC-J2 cells (p < 0.05). Furthermore, siRNA GPR109A knockdown significantly abrogated the protective effect of niacin on ETEC K88-induced cell damage (p < 0.05); (4) Conclusions: Niacin supplementation increased AQPs and ZO-1 expression to reduce diarrhea and intestinal damage through GPR109A pathway in weaned piglets.