Mannan oligosaccharide increases the growth performance, immunity and resistance capability against Vibro Parahemolyticus in juvenile abalone Haliotis discus hannai Ino

Dietary supplementation modified attapulgite promote intestinal epithelial barrier and regulate intestinal microbiota composition to prevent diarrhea in weaned piglets

Attapulgite is a kind of natural clay mineral. Its unique pore structure makes it an ideal adsorption material and carrier material. However, the beneficial effect of modified attapulgites (SLK) in livestock is still unknown. The study was aimed to investigate the beneficial effect of modified attapulgites on diarrhea. 135 piglets were randomly divided into 5 groups and fed with control diet, traditional antibiotic substitute (TAS) supplementation diet, 0.5 mg/kg SLK supplementation diet, 1 mg/kg SLK supplementation diet, and 1.5 mg/kg SLK supplementation diet. This experiment lased two weeks. According to our result, 1.5 mg/kg SLK supplementation diet significantly decreased diarrhea score and diarrhea frequency, and effectively increased survival rate (P < 0.05). Dietary supplementation with 1.5 mg/kg SLK significantly increased high density lipoprotein cholesterol (HDLC), and choline esterase (CHE) concentration in serum (P < 0.05). AS compared with TAS group, 1.5 mg/kg SLK supplementation diet significantly decreased villus height and increased goblet number in jejunum, and increased villus height and decreased goblet number in ileum (P < 0.05). 1.5 mg/kg SLK supplementation diet also significantly changed cecal microbial community composition, including increased Limosilactobacillus abundance (P < 0.05). 1.5 mg/kg SLK supplementation diet significantly increased colonic microbial community composition, including decreased Escherichia-shigella abundance and increased Limosilactobacillus abundance (P < 0.05). Moreover, 1.5 mg/kg SLK supplementation diet significantly increased valerate, propionate, butyrate, and total short chain fatty acid contents in colon (P < 0.05). Valerate, propionate, butyrate, and total short chain fatty acid significantly associated with Lactobacillus. Fourerenilla and Fourerenilla.unclassfied significantly associated with acetate contents in colon (P < 0.05). In conclusion, dietary supplementation with modified apptapulgites significantly regulate intestinal microbial community composition and alleviate intestinal epithelial barrier to prevent diarrhea in piglets.

The Purification and Biochemical Characterization of a Weissella cibaria F1 Derived β-Mannanase for Its Use in the Preparation of Konjac Oligo-Glucomannan with Immunomodulatory Properties

Mannanase with a molecular weight of 33.1 kDa was purified from Weissella cibaria F1. The F1 mannanase contained 289 amino acid residues and shared 70.0% similarity with mannanase from Bacillus subtilis (P55278 (MANB_BACIU)). The optimum reaction conditions of F1 mannanase were 50 °C and pH 6.5. After incubation at pH 4.5–8.0 and 30–60 °C for 2 h, the enzyme activity remained above 60%. The effects of metal ions on mannanase enzyme activity were measured, and Mn2+, Mg2+, and Cu2+ increased enzyme activity. The Km (16.96 ± 0.01 μmol·mL−1) and Vmax (1119.05 ± 0.14 μmol·min−1) values showed that the enzyme exhibited high affinity for locust bean gum. Mannanase was used to hydrolyze konjac glucomannan to produce konjac oligo-glucomannan (KOGM). KOGM increased the proliferation and phagocytosis of RAW264.7 macrophages and enhanced nitric oxide, and cytokine production in macrophages, which showed potent immunostimulatory activity. In this study, the advantages of mannanase derived from lactic acid bacteria were utilized to expand the application of KOGM in the medical field, which is helpful to explore the broad prospects of KOGM in functional food or medicine.

Dietary Mannan Oligosaccharides Enhance the Non-Specific Immunity, Intestinal Health, and Resistance Capacity of Juvenile Blunt Snout Bream (Megalobrama amblycephala) Against Aeromonas hydrophila

Mannan oligosaccharides (MOS) have been studied and applied as a feed additive, whereas their regulation on the growth performance and immunity of aquatic animals lacks consensus. Furthermore, their immunoprotective effects on the freshwater fish Megalobrama amblycephala have not been sufficiently studied. Thus, we investigated the effects of dietary MOS of 0, 200, and 400 mg/kg on the growth performance, non-specific immunity, intestinal health, and resistance to Aeromonas hydrophila infection in juvenile M. amblycephala. The results showed that the weight gain rate of juvenile M. amblycephala was not significantly different after 8 weeks of feeding, whereas the feed conversion ratio decreased in the MOS group of 400 mg/kg. Moreover, dietary MOS increased the survival rate of juvenile M. amblycephala upon infection, which may be attributed to enhanced host immunity. For instance, dietary MOS increase host bactericidal and antioxidative abilities by regulating the activities of hepatic antimicrobial and antioxidant enzymes. In addition, MOS supplementation increased the number of intestinal goblet cells, and the intestine was protected from necrosis of the intestinal folds and disruption of the microvilli and junctional complexes, thus maintaining the stability of the intestinal epithelial barrier. The expression levels of M. amblycephala immune and tight junction-related genes increased after feeding dietary MOS for 8 weeks. However, the upregulated expression of immune and tight junction-related genes in the MOS supplemental groups was not as notable as that in the control group postinfection. Therefore, MOS supplementation might suppress the damage caused by excessive intestinal inflammation. Furthermore, dietary MOS affected the richness and composition of the gut microbiota, which improved the gut health of juvenile M. amblycephala by increasing the relative abundance of beneficial gut microbiota. Briefly, dietary MOS exhibited significant immune protective effects to juvenile M. amblycephala, which is a functional feed additive and immunostimulant.

Transcriptome analysis of Neocaridina denticulate sinensis challenged by Vibrio parahemolyticus

As a common aquatic pathogen, Vibrio parahaemolyticus can cause a variety of diseases of shrimp, especially acute hepatopancreatic necrosis disease (AHPND), which leads to great losses to the aquaculture industry around the world. However, the molecular mechanism of V. parahaemolyticus infection is still unclear. Neocaridina denticulate sinensis is a kind of small ornamental shrimp that is popular in aquarium trade, and due to its tenacious vitality, rapid growth, high reproductive capacity, it is very suitable to be developed as an animal model for basic research on decapod crustaceans. Thus, in this paper, transcriptomes of N. denticulate sinensis hepatopancreas with or without V. parahaemolyticus injection were explored. The results showed that a total of 23,624 genes with the N50 of 2705 bp were obtained. Comparative transcriptomic analysis revealed 21,464 differentially expressed genes between the V. parahaemolyticus infected and non-infected group, of which, 11,127 genes were up-regulated and 10,337 genes were down-regulated. Functional enrichment analysis suggested that many DEGs enriched in immune related pathways, including MAPK signaling pathway, Phosphatidylinositol signaling system, Chemokine signaling pathway, Phagosome and Jak-STAT signaling pathway and so on. Eight genes were selected randomly for qRT-PCR to verify the transcriptome sequencing results and the results showed the expression of these genes were consistent with the transcriptome results. Our work provides a unique and important dataset that contributes to the understanding of the molecular mechanisms of the immune response to V. parahaemolyticus infection and may further provide the basis for the prevention and resolution of bacterial diseases.

Effects of mannan oligosaccharides on growth performance, nutrient digestibility, ruminal fermentation and hematological parameters in sheep

Background

Mannan oligosaccharides (MOS) are a promising feed additive in animal husbandry due to mainly improving animal health status. The purpose of this study was to investigate the effects of MOS on growth performance, nutrient digestibility, ruminal fermentation, and twelve hematological parameters in sheep.

Methods

Ninety-six healthy Hu rams with similar body weights were chosen and divided into four treatment groups (twenty-four rams in each group), in which four different doses of MOS were tested: 0%, 0.8%, 1.6% and 2.4% of the basal diet (on an as-fed basis).

Results

The results showed that supplementation dietary MOS did not affect feed intake, body weight, average daily weight gain, or ruminal short-chain fatty acids (SCFAs) concentration; the ratio of individual fatty acids to total SCFAs, the C2/C3 ratio, and the hematological parameters in the sheep were also unaltered (P > 0.05). Conversely, supplementation dietary MOS increased the dry matter, organic matter, crude protein, neutral detergent fiber, acid detergent fiber, and ash apparent digestibility (P < 0.05), and decreased the ruminal ammonia concentration in the sheep (P < 0.05), especially at a dose of 1.6%.

Conclusions

This indicates that supplementation dietary MOS improved nutrient utilization by the sheep and nitrogen metabolism in the rumen; however, the effects are too slight to interfere with the basal metabolism in the sheep.

Modulation of the growth performance and innate immunity of loaches (Paramisgurnus dabryanus) upon dietary mannan oligosaccharides

Different levels of mannan oligosaccharides (MOs) (100, 300 and 500 mg kg^-1) were incorporated into a basal diet to formulate three diets, which were used to test the growth performance and innate immunity of loaches. The basal diet without any MOs served as the control. Loaches fed with MO-containing diets for 70 days showed a higher specific growth rate, condition factor, survival rate, intestine weight index, intestine length index, intestine Lactobacillus population, intestine Bifidobacterium population, phenoloxidase activity, superoxide dismutase activity, glutathione peroxidase activity, acid phosphatase activity, alkaline phosphatase activity, lysozyme level, complement 3 and resistance to Aeromonas hydrophila than the loaches in the control group. The feed conversion ratio, intestine Escherichia coli population, malondialdehyde level, aspartate aminotransferase level and alanine aminotransferase level showed an opposite trend. The optimal dose of dietary MOs required for the maximum growth of loaches was 300 mg kg^-1. Results indicated that dietary MOs promoted the growth performance and innate immunity of loaches and could be used as a dietary supplement for loaches.