Autochthonous Probiotics Alleviate the Adverse Effects of Dietary Histamine in Juvenile Grouper (Epinephelus coioides)

Integrative analysis of metagenome and metabolome provides new insights into intestinal health protection in Coilia nasus larvae via probiotic intervention

With the development of large-scale intensive feeding, growth performance and animal welfare have attracted more and more attention. Exogenous probiotics can promote the growth performance of fish through improving intestinal microbiota; however, it remains unclear whether intestinal microbiota influence physiological biomarkers. Therefore, we performed metagenomic and metabolomic analysis to investigate the effects of a 90-day Lactiplantibacillus plantarum supplementation to a basal diet (1.0 × 108 CFU/g) on the growth performance, intestinal microbiota and their metabolites, and physiological biomarkers in Coilia nasus larvae. The results showed that the probiotic supplementation could significantly increase weight and body length. Moreover, it could also enhance digestive enzymes and tight junctions, and inhibit oxidative stress and inflammation. The metagenomic analysis showed that L. plantarum supplementation could significantly decrease the relative abundance of Proteobacteria and increase the relative abundance of Firmicutes. Additionally, pathogenic bacteria (Aeromonadaceae, Aeromonas, and Enterobacterales) were inhibited and beneficial bacteria (Bacillales) were promoted. The metabolome analysis showed that acetic acid and propanoic acid were significantly elevated, and were associated with Kitasatospora, Seonamhaeicola, and Thauera. A correlation analysis demonstrated that the digestive enzymes, tight junction, oxidative stress, and inflammation effects were significantly associated with the increased acetic acid and propanoic acid levels. These results indicated that L. plantarum supplementation could improve intestinal microbial community structure and function, which could raise acetic acid and propanoic acid levels to protect intestinal health and improve growth performance in C. nasus larvae.

Clinical Implications of Dietary Probiotic Supplement (Associated with L-Glutamine and Biotin) in Ulcerative Colitis Patients' Body Composition and Quality of Life

Patients with ulcerative colitis (UC) are reported to have changes in body structure, with negative impact on the course of disease. This study explored the effects of a standardized nutritional supplement containing five bacterial strains of at least five billion bacteria (Bifidobacterium infantis, Bifidobacterium animalis, Lactobacillus bulgaricus, Lactobacillus helveticus, and Enterococcus faecium), L-glutamine, and biotin on the body composition and quality of life of patients with UC. Ninety-three patients over 18 years of age with a confirmed diagnosis of UC, for whom body composition could be accurately determined, were included in this observational follow-up randomized study. These patients were split into two groups: UC-P (44 patients with dietary counselling and supplement with probiotics) and UC-NP (49 patients with dietary counselling, without supplement). Body composition was assessed using the multifrequency bioelectrical impedance device, and the quality of life related to UC was evaluated by applying the short inflammatory bowel disease questionnaire (SIBDQ). The results showed that the average value of muscular mass (MM) and sarcopenic index (SMI) significantly increased (p = 0.043, respectively, p = 0.001) and a large fraction (p = 0.001) of patients had their SMI levels normalized in the UC-P group compared with UC-NP group. The extracellular water to total body water ratio (ECW/TBW) also had significantly different mean values (p = 0.022), favoring the UC-P group. By testing the differences between the average values of body composition parameters before and after treatment, we obtained significant results in body mass index (BMI) (p = 0.046), fat free mass (FFM) (p < 0.001), and ECW/TBW ratio (p = 0.048). The SIBDQ total score increased significantly (p < 0.001) in the UC-P group and was more strongly associated with changes in body parameters. Supplementation with probiotics associated with L-glutamine and biotin can improve body composition parameters, which in turn implies an increase in the overall quality of life of patients with UC.

Dietary n-3/n-6 polyunsaturated fatty acid ratio modulates growth performance in spotted seabass (Lateolabrax maculatus) through regulating lipid metabolism, hepatic antioxidant capacity and intestinal health

An 8-week feeding experiment was carried out to explore the effects of dietary n-3/n-6 polyunsaturated fatty acid (PUFA) ratio on growth performance, lipid metabolism, hepatic antioxidant status, and gut flora of spotted seabass (Lateolabrax maculatus). Six experimental diets were formulated to contain different levels of two purified oil sources including docosahexaenoic and eicosapentaenoic acids enriched oil (n-3) and linoleic acid-enriched oil (n-6) leading to n-3/n-6 PUFA ratios of 0.04, 0.35, 0.66, 1.35, 2.45 and 16.17. Each diet was fed to triplicate groups of juvenile L. maculatus (11.06 ± 0.20 g, 30 fish/tank). Final body weight (FBW), weight gain (WG), specific growth rates (SGR), protein efficiency ratio (PER) and feed utilization efficiency increased as n-3/n-6 PUFA ratio increased up to a certain level, and then decreased thereafter. Fish fed the diet with n-3/n-6 PUFA ratio of 0.66 exhibited the highest FBW, WG, SGR and PER and the lowest feed conversion ratio. Lower n-3/n-6 PUFA ratios induced up-regulated expression of lipid synthesis-related genes (fas, acc2 and srebp-1c) and down-regulated expression of lipolysis related genes (atgl, pparα, cpt-1 and aox). Higher expression of lipolysis-related genes (atgl, pparα and cpt-1) was recorded at moderate n-3/n-6 PUFA ratios (0.66 to 1.35). Moreover, inappropriate n-3/n-6 PUFA ratios triggered up-regulation of pro-inflammatory genes (il-6 and tnf-α) and down-regulation of anti-inflammatory genes (il-4 and il-10) in the intestine. The diet with n-3/n-6 PUFA ratio of 0.66 inhibited intestine inflammation, improved intestinal flora richness, increased the abundance of beneficial bacteria such as Lactobacillus, Alloprevotella and Ruminococcus, and reduced the abundance of harmful bacteria including Escherichia-Shigella and Enterococcus. In summary, it could be suggested that a dietary n-3/n-6 PUFA ratio of 0.66 can improve growth performance and feed utilization in L. maculatus, as is deemed to be mediated through regulation of lipid metabolism and intestinal flora.

Autochthonous Bacillus subtilis and Enterococcus faecalis improved liver health, immune response, mucosal microbiota and red-head disease resistance of yellow drum (Nibea albiflora)

Yellow drum (Nibea albiflora), a commercially important fish species in the coastal regions of southeast China, is highly susceptible to red-head disease caused by Vibrio harveyi B0003. Probiotics have been shown to enhance disease resistance in fish, but whether commensal probiotics could improve of the resistance to red-head disease in yellow drum and possible mechanisms has yet not been reported. A six-week feeding trial was conducted to investigate the red-head disease resistance potentials of five probiotic candidates (Bacillus megaterium B1M2, B. subtilis B0E9, Enterococcus faecalis AT5, B. velezensis DM5 and B. siamensis B0E14), and the liver health, serum and skin immunities, gut and skin mucosal microbiota of yellow drum were determined to illustrate the possible mechanisms. The results showed that autochthonous B. subtilis B0E9 and E. faecalis AT5 (particularly E. faecalis AT5, P < 0.05) effectively improved red-head disease resistance in yellow drum. Furthermore, B. subtilis B0E9 and E. faecalis AT5 (particularly E. faecalis AT5) efficiently improve liver health by improving liver morphology and decreasing serum glutamic oxaloacetic transaminase and glutamic propylic transaminase activities pre and post challenged with V. harveyi B0003 (P < 0.05). B. subtilis B0E9 and E. faecalis AT5 led to significant improvement (P < 0.05) in the serum complement 3 content (un-detected after challenged with V. harveyi B0003), lysozyme activity and skin mucosal immunity (such as IL-6, IL-10 and lysozyme expression) pre and post challenged with V. harveyi B0003, which was generally consistent with the cumulative mortality after challenged with V. harveyi B0003. This induced activations of serum and skin mucosal immunities were consistent with the microbiota data showing that B. subtilis B0E9 and E. faecalis AT5 modulated the overall structure of intestinal and skin mucosal microbiota, and in particular, the relative abundance of potentially pathogenic Achromobacter decreased while beneficial Streptococcus, Rothia, and Lactobacillus increased in fish fed with B. subtilis B0E9 and E. faecalis AT5. Overall, autochthonous B. subtilis B0E9 and E. faecalis AT5 (particularly E. faecalis AT5) can improve liver health, serum and skin immunities (especially up-regulated lysozyme activity and inflammation-related genes expression), positively shape gut and skin mucosal microbiota, and enhance red-head disease resistance of yellow drum.

Preventive and reparative functions of host-associated probiotics against soybean meal induced growth, immune suppression and gut injury in Japanese seabass (Lateolabraxjaponicus)

A 56-day feeding trial was conducted to examine the preventive and reparative functions of host-associated probiotics against high soybean meal (SM)-induced negative effects in Japanese seabass (Lateolabrax japonicus). Fish continuously fed low SM (containing 16% SM) and high SM (containing 40% SM) diets were named as positive (PC) and negative (C) control, respectively. Preventive functions of probiotics were evaluated by continuously feeding diets LF3 (Lactococcus petauri LF3 supplemented in high SM diet, group PLF3) and LF4 (Bacillus siamensis LF4 supplemented in high SM diet, group PLF4), while reparative functions were estimated by feeding the high SM diet during 0-28 days, then feeding diets LF3 (group RLF3) and LF4 (group RLF4) until day 56. Compared with the group PC, suppressed growth and immunity, and damaged intestinal health were observed in the group C on days 28 and 56. Fish in groups PLF3 and PLF4, rather than in groups RLF3 and RLF4, showed higher growth compared with the group C and displayed similar immune status to the group PC, indicating that the initial and continued application of probiotic LF3 and LF4 can efficiently improve high SM induced growth and immune deficiency in Japanese seabass, but probiotics had limited reparative benefits when they were administrated at the middle of the feeding trial (28 d). Furthermore, probiotics showed good preventive functions and limited reparative functions on gut health via improving intestinal morphology and inflammation markers, for example, decreasing diamine oxidase activity and d-lactate content, while up-regulating anti-inflammatory TGF-β1 expression and down-regulating pro-inflammatory TNF-α, IL-1β, and IL-8 expressions. Moreover, dietary supplementation of probiotics (especially on day 56) could effectively shape the gut microbiota, such as significantly decreasing abundances of opportunistic pathogens (phylum Actinobacteria, genera Pseudomonas and Moheibacter on day 28, phylum Proteobacteria, genus Plesiomonas on day 56), significantly increasing gut microbial diversity and abundances of possible beneficial bacteria (phylum Bacteroidetes and genus Lactobacillus on day 28, phyla Firmicutes, Bacteroidetes and Cyanobacteria, genera Bacillus, Lactobacillus and Bacteroides on day 56). In conclusion, we evidenced for the first time that host-associated L. petauri LF3 and B. siamensis LF4 can provide effectively preventive and certain reparative functions against high SM-induced adverse effects in L. japonicus.