Effects of dietary mixed probiotics on growth, non-specific immunity, intestinal morphology and microbiota of juvenile pacific white shrimp, Litopenaeus vannamei.

This study was conducted to elucidate the effects of dietary mixed probiotics on growth, non-specific immunity, intestinal morphology and microbiota of juvenile pacific white shrimp, Litopenaeus vannamei. Juvenile shrimp (initial body weight 1.21 ± 0.01 g) were fed diets containing graded probiotics (F1: 0 mg/kg probiotics; F2: 1000 mg/kg probiotics; F3: 2000 mg/kg probiotics; F4: 4000 mg/kg compound probiotics; F5: 6000 mg/kg probiotics; F6: 8000 mg/kg probiotics) for 8 weeks. The result of this trial showed that the growth performance (SGR, WG, FBW) of shrimp fed diets containing probiotics (F2∼F6) were significantly higher than that of shrimp fed diet without supplemental probiotics (F1) (P < 0.05), and the highest values of the growth performance (SGR, WG, FBW) and lowest FCR were found in shrimp fed the diet containing 2000 mg/kg probiotics. Total antioxidant capacity of shrimp fed diet F2 and F3 were significantly higher than that of shrimp fed the basal diets (P < 0.05). Superoxide dismutase in F4 treatment was significantly higher than that of basal treatment (P < 0.05). Catalase of shrimp in all probiotics supplemented (F2∼F6) treatments were significantly higher than that of the control one (F1) (P < 0.05). Malondialdehyde in F5 groups was significantly lower than that of F1 groups (P < 0.05). Alkline phosphatase and acid phosphatase in F3 treatments were significantly higher than those of the basal one (P < 0.05). Lysozyme of shrimp fed F2∼F6 were significantly higher than that of shrimp fed F1 diet (P < 0.05). The lipase and amylase activities in 2000 mg/kg probiotics groups showed the highest activities and were significantly higher than that of control one (P < 0.05). Intestinal villi height in F3∼F6 treatments were significantly higher than that of control one (P < 0.05). Alpha diversity indices including observed species, chao1, ACE and shannon indices showed that F2 and F3 groups had higher microbial diversity in their intestines, both richness and evenness. PCA plot showed that there was a clear shift of F2 and F3 groups from the control groups in microbial community structure. The dominant phyla in pacific white shrimp are proteobacteria, bacteroidetes and actinobacteria, the dominant genus were algoriphagus and vibrio. As the probiotics increased, the gemmatimonadetes, acidobacteria, deltaproteobacteria and xanthomonadales firstly increased and then decreased, with the highest content in F2 group, which was no significant difference to F3 group (P > 0.05) while significantly higher than other groups (P < 0.05). In conclusion, the supplement of mixed species probiotics can promote growth performance, enhance the non-specific immunity, influence the microbiota of the pacific white shrimps and the recommended optimum dosage in diet of Litopenaeus vannamei was 2000 mg/kg.

Xie JJ ，Liu QQ ，Liao S ，Fang HH ，Yin P ，Xie SW ，Tian LX ，Liu YJ ，Niu J ... -  《-》

Dietary supplementation of probiotic Bacillus coagulans ATCC 7050, improves the growth performance, intestinal morphology, microflora, immune response, and disease confrontation of Pacific white shrimp, Litopenaeus vannamei.

The present study assessed the effects of probiotic bacterium Bacillus coagulans ATCC 7050 (BC) fed at different inclusion levels (0 (BO), 1 × 106 (BC1), 1 × 107 (BC2) and 1 × 108 (BC3) CFU g-1 feed) on growth, feed utilization, body composition, intestinal morphology, microflora, immune response, and resistance to Vibrio parahaemolyticus infection in Litopenaeus vannamei. After 56 days of the feeding trial, the survival rate ranged from 83.33 to 94.17% with no significant difference between dietary treatments (P > 0.05). Dietary probiotic supplementation also affected the intestinal microflora composition. At the phylum level, Proteobacteria accounted for the majority of bacteria followed by Bacteroidetes irrespective of the group. At the genus level, the abundance of opportunistic pathogenic bacteria, such as Vibrio, Tenacibaculum, and Photobacterium significantly decreased (P < 0.05) with an increasing probiotic concentration, and BC3 group experiencing the least. Additionally, increasing probiotic inclusion in diet downregulated the abundance of Muricauda, Kangiella, and Shewanella in shrimps, with the least, observed in the BC3 group. However, beneficial bacteria Pseudoalteromonas significantly increased (P < 0.05) in the intestines of shrimp fed BC3 diet (P < 0.05) compared to other groups including the control. Compared to the control, a significant increase (P < 0.05) of the probiotic treated groups in the final weight, weight gain rate (WGR), specific growth rate (SGR), condition factor (K), activity of lysozyme (LYZ), acid phosphatase (ACP), superoxide dismutase (SOD), total protein (TP), albumin (ALB) in serum, glutathione peroxidase (GSH-Px) in serum and liver, and a significant decrease (P < 0.05) in feed conversion ratio (FCR), triglyceride (TG) in serum, and Malondialdehyde (MDA) in serum and liver were achieved. Increasing probiotic treatment again improved the digestive ability, thus; a significant increase in the activities of lipase, amylase, trypsin, and an enhancement in the villus height, villus width, and muscle thickness of the intestines of the shrimps which correspondingly alleviated intestinal injury. Furthermore, the supplementation of probiotics in challenge test significantly (P < 0.05) enhanced the resistance of shrimp against V. parahaemolyticus infection recording BC3 to receive the highest relative percentage survival (RPS) value of 76%. In conclusion, higher inclusion levels of probiotic BC at 1 × 108 CFU g-1 feed (BC3) in diets can be considered to enhance the growth, intestinal morphology and microflora, immune response and resistance to Vibrio parahaemolyticus of L. vannamei.

Amoah K ，Huang QC ，Tan BP ，Zhang S ，Chi SY ，Yang QH ，Liu HY ，Dong XH ... -  《-》

Effects of dietary synbiotics supplementation methods on growth, intestinal health, non-specific immunity and disease resistance of Pacific white shrimp, Litopenaeus vannamei.

The present study aims to investigate the effects of dietary synbiotics supplementation methods on growth, feed utilization, hepatopancreas and intestinal histology, non-specific immunity and microbiota community of Pacific white shrimp (Litopenaeus vannamei). A control diet was designed to contain 18% fish meal (CON), and then 3 g kg-1 synbiotics (Bioture, consisting of Bacillus subtilis, Saccharomyces cerevisiae, β-glucan and mannan oligosaccharide, etc) was supplemented to the control diet with three methods, directly adding in diets for pelleting (DAP), spraying diets after pelleting at once (SDA), spraying diets before feeding every day (SDE). Shrimp with initial body weight of 1.5 ± 0.12 g were fed one of the four diets for 56 days. The results showed that dietary synbiotics significantly increased the weight gain (WG), apparent digestibility coefficient (ADC) of crude protein (CP) and dry matter (DM), hepatopancreatic protease activity and decreased feed conversion ratio (FCR) (P < 0.05). Among the three synbiotics-added diets, SDE group showed the best growth with significantly higher WG than DAP group (P < 0.05). Serum activities of total superoxide dismutase, catalase, acid phosphatase, lysozyme and alkaline phosphatase of synbiotics-added groups were significantly higher, and serum malondialdehyde level was significantly lower than those of the control (P < 0.05). The intestinal villus width and villus number were also increased by the supplementation of synbiotics. The cumulative mortality was reduced in the three synbiotics-added groups after challenging with Vibrio parahaemolyticus (P < 0.05), and SDE group showed a significantly lower mortality than the control and DAP groups (P < 0.05). In intestinal microbiota composition, the abundance of Lactococcus tended to increase and Vibro tended to decreased in SDA and SDE groups. In conclusion, dietary synbiotics improved the growth, feed utilization, intestine health and non-specific immunity of Pacific white shrimp, and spraying synbiotics on diet presented better performance than adding synbiotics in diet for pelleting.

Yao W ，Li X ，Zhang C ，Wang J ，Cai Y ，Leng X ... -  《-》

Improvement of growth, intestinal short-chain fatty acids, non-specific immunity and ammonia resistance in Pacific white shrimp (Litopenaeus vannamei) fed dietary water-soluble chitosan and mixed probiotics.

This study was to explore the impacts of water-soluble chitosan and mixed probiotics on growth performance, intestinal short-chain fatty acids (SCFAs) and immunity and ammonia resistance in Litopenaeus vannamei. Shrimp were fed one of four experimental diets including basal diet (CON), 0.10% water-soluble chitosan diet (WSC), 0.30% mixed probiotics (MP) and 0.10% water-soluble chitosan +0.30% mixed probiotics (SYN) for 8 weeks. Results showed shrimp fed with dietary MP and SYN diets could significantly improve growth performance and feed utilization in comparison with those of shrimp fed with CON diet (P < 0.05). Acetic acid content was significantly higher in shrimp fed with all supplemented diets compared to that in shrimp fed with CON diet (P < 0.05). Compared to shrimp fed with CON diet, dietary WSC and MP significantly influenced the contents and/or activities of aspartate aminotransferase (AST), total protein (TP), superoxide dismutase (SOD), lysozyme (LZM) in serum, SOD, malondialdehyde (MDA), acid phosphatase (ACP) in hepatopancreas and SOD and MDA in intestine. In addition, the gene expression levels of prophenoloxidase (proPO), penaiedin 3a (Pen-3a), crustin (Crustin), serine proteinase (SP), GPX and SOD in hepatopancreas, were significantly upregulated compared to those in CON diet at some time points (P < 0.05). Significantly higher survival rate in all supplemented diets were observed after ammonia challenge (P < 0.05). Therefore, the above results indicated dietary WSC and MP or SYN could enhance intestinal SCFAs content, stimulated antioxidant capacity and immune response, and increase the ammonia resistance of Litopenaeus vannamei. Besides, the growth performance was also improved by dietary MP and SYN.

Chen M ，Chen XQ ，Tian LX ，Liu YJ ，Niu J ... -  《-》

Effects of dietary mannan oligosaccharide on growth performance, gut morphology and stress tolerance of juvenile Pacific white shrimp, Litopenaeus vannamei.

An 8-week feeding trial was conducted to investigate the effects of dietary mannan oligosaccharide (MOS) on growth performance, gut morphology, and NH(3) stress tolerance of Pacific white shrimp Litopenaeus vannamei. Juvenile Pacific white shrimp (1080 individuals with initial weight of 2.52 ± 0.01 g) were fed either control diet without MOS or one of five dietary MOS (1.0, 2.0, 4.0, 6.0 and 8.0 g kg(-1)) diets. After the 8-week feeding trial, growth parameters, immune parameters, intestinal microvilli length and resistance against NH(3) stress were assessed. Weight gain (WG) and specific growth rate (SGR) were significantly higher (P < 0.05) in shrimp fed 2.0, 4.0, 6.0 and 8.0 g kg(-1) MOS-supplemented diets than shrimp fed control diet. WG and SGR of shrimp fed 2.0 g kg(-1) MOS-supplemented diet was the highest (P < 0.05) in all experimental groups. Survival rate (SR) of shrimp was generally similar (P > 0.05) in all experimental groups. Compared with control group, TEM analysis revealed that 2.0, 4.0, 6.0 and 8.0 g kg(-1) MOS supplementation could significantly increase (P < 0.05) the intestinal microvilli length of shrimp at the ultrastructural level. After NH(3) stress for 24 h, SR of shrimp fed 2.0, 4.0, 6.0 and 8.0 g kg(-1) MOS-supplemented diets was significantly higher (P < 0.05) than that of shrimp fed control diet. Phenoloxidase (PO) activity of 4.0 g kg(-1) MOS-supplemented group was significantly higher (P < 0.05) than that of control group under normal conditions and NH(3) stress. PO activity significantly decreased (P < 0.05) under NH(3) stress than under normal conditions. Superoxide dismutase (SOD) activity of 4.0, 6.0 and 8.0 g kg(-1) MOS-supplemented groups was significantly higher (P < 0.05) than that of control group under normal conditions. After NH(3) stress for 24 h, SOD activity of all experimental groups also significantly decreased (P < 0.05) compared to normal conditions. These results clearly indicated that dietary MOS could improve growth performance and increase the resistance against NH(3) stress in L. vannamei, and the 2.0-4.0 g kg(-1) MOS supplementation was suitable for L. vannamei.

Zhang J ，Liu Y ，Tian L ，Yang H ，Liang G ，Xu D ... -  《-》