Search

The effects of food type, salinity and temperature on the growth performance and antioxidant status of Hippocampus reidi juveniles at 2.5 months old were evaluated in this study. Three trials were conducted for 56 days. Seahorses fed frozen mysid shrimp (MD) exhibited significantly higher survival, growth performance and feed efficiency compared with that of seahorses fed frozen adult Artemia (AD) or a mixture consisting of MD and AD at the ratio of 1:1 (MAD). Mortality of seahorse cultured at 30°C reached 100% at 49 days. Despite no significant difference, the survival and growth performance of seahorses were higher at 26 than 28°C. Seahorses had better growth performance at salinities of 15–20 ppt, but the survival and growth performance of seahorses were not significantly different among salinity groups. Seahorses fed MD or MAD had better antioxidant status based on the results of total phenolic content (TPC) and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity in the MD and MAD groups, and significantly higher reducing power in MD than AD. No significant difference in all antioxidant indicators was recorded in 26 and 28°C groups. TPC, DPPH radical scavenging activity and ferric reducing antioxidant power activity of seahorses were significantly higher at 15 and 20 ppt, and metal chelating activity of seahorses at 15 ppt was significantly higher than that of seahorses at higher salinities. Based on these results, H. reidi juvenile is recommended to be fed MD at a temperature of 26°C and salinity of 15–20 ppt. [ABSTRACT FROM AUTHOR]

The purpose of the present study is to profile the microfloral structure in the intestines of the white shrimp, Litopenaeus vannamei, after being fed a control diet, in comparison with the diets containing Bacillus subtilis E20‐fermented soybean meal (FSBM) or an antimicrobial peptide (AMP) isolated from B. subtilis E20‐FSBM (diets designated FSBMD and AMPD, respectively) for 60 days. Metagenomic data showed detection of eight phyla, 20 classes, 40 orders, 68 families and 96 genera. Despite no statistically significant difference, an evaluation of microbial diversity recorded higher species richness, Shannon–Weaver diversity index and evenness in the AMPD and FSBMD groups, compared to the control diet group. Venn diagrams showed that 58 of the operational taxonomic units (OTUs) were shared among the control, FSBMD and AMPD groups, but additional beneficial microbes were only found in the FSBMD and AMPD groups. In addition to the augmentation of beneficial bacteria in the FSBMD and AMPD groups, the abundance of potential pathogens, Vibrio and Flavobacterium, was lower in the gut of shrimp fed the FSBMD and AMPD. The results clearly suggest that the FSBMD and AMPD have the capability to change the microfloral structure of shrimp intestines and could be used for disease prevention in shrimp aquaculture. [ABSTRACT FROM AUTHOR]

The aims of this study were to evaluate the probiotic efficiency of Bacillus subtilis E20 (109 colony‐forming units kg−1) on the growth and apparent digestibility coefficients (ADCs) of dry matter (DM), crude protein (CP), amino acids (AAs), and crude lipids (CLs) of the white shrimp, Litopenaeus vannamei. A control diet without probiotic supplementation was used. Shrimp exhibited significant increases in growth performance and feed utilization after being fed the test diet for 56 days. Shrimp were then used to evaluate the apparent nutrient digestibility using 0.1% Cr2O3 in the diet as an indicator. During the trial, faeces was collected from triplicate groups of shrimp twice daily. ADCs of CP and DM in the test diet significantly increased compared to those of the control diet. Although the ADCs of CLs did not significantly differ between the control and probiotic group, the ADC of CLs was higher in the probiotic group than in the control group. In addition, ADCs of most AAs in the test diet were significantly higher compared to those of the control diet. These results suggest that shrimp in the test group had significantly better growth performance, which was due to increases in nutrient digestibility and absorption. [ABSTRACT FROM AUTHOR]

Abstract: This study aimed to develop a synbiotic combination with probiotic, Lactobacillus plantarum 7–40 and one of three prebiotics, fructooligosaccharide (FOS), galactooligosaccharide (GOS) and mannan oligosaccharide (MOS). The best in vitro growth was observed when probiotic was cultured in the medium containing either FOS or GOS as the sole of carbon source. The analysis of enzyme activity revealed that GOS induced the highest activities of protease and β‐galactosidase of probiotic. Based on the findings, probiotic + GOS were selected as synbiotic to evaluate if it could promote the growth of white shrimp, Litopenaeus vannamei. For this, four diets, including a basal diet with no GOS or probiotic (control), 0.4% GOS (PRE), 108 CFU probiotic kg−1 (PRO) and 0.4% GOS in combination with 108 CFU probiotic kg−1 (SYN), were fed to shrimp for 60 days, and then the growth performance, intestinal microbiota (including total Vibrio counts, VBCs; and lactic acid bacteria, LAB) and digestive enzyme (including protease, leu‐aminopeptidase and β‐galactosidase) were evaluated. The weight gain (WG) of shrimp fed the PRO did not significantly differ from those of control (p > .05). Shrimp fed the SYN had significantly higher WG compared with the other treatments (p < .05). In addition, the SYN‐fed shrimp had significantly higher LAB and protease, leu‐aminopeptidase and β‐galactosidase activity (p < .05). The lowest presumptive Vibrio count (VBC) was also observed in intestines of SYN‐fed shrimp. Therefore, we suggested that Lac. plantarum 7–40+ GOS can be used as a synergistic synbiotic for shrimp culture. [ABSTRACT FROM AUTHOR]

An experiment was conducted to evaluate the potential of a Bacillus subtilis E20-fermented mixture ( FSFEM) containing soybean meal ( SBM) and Eisenia fetida earthworm meal ( EM) at a ratio of 4:1 to increase the methionine level in order to satisfy the methionine requirement of white shrimp, Penaeus vannamei in a diet with fish meal ( FM) completely replaced by mixtures. B. subtilis E20 fermentation improved the mixture's palatability and utilization based on better growth performance in comparison to shrimp fed FSEM (contains fermented SBM and EM at a ratio of 4:1) diets. FSFEM is a good substitute for FM. Maximal replacement levels of FM with FSFEM were 80% in a shrimp diet with 37% of crude protein and 7% of crude lipid based on weight gain and 100% based on feeding efficiency. In addition, shrimp fed experimental diets had no significant differences in survival after being challenged by Vibrio alginolyticus. It is suggested that B. subtilis E20- FSFEM has the potential to replace FM in cultured shrimp diets. [ABSTRACT FROM AUTHOR]

Six fish meal basal diets supplied with 0 (control), 0.25, 0.5, 1, 2.5 and 5 g kg−1 of choline chloride, resulting in choline levels of 2.57, 2.67, 2.94, 3.84, 4.99 and 7.71 g kg−1, respectively, were fed to giant grouper, Epinephelus lanceolatus, for 56 and 30 days to evaluate the growth and lipid metabolism, and stress tolerance respectively. In the first trial, fish fed different levels of choline-containing diets for 56 days had no significant difference in weight gain, survival and feeding efficiency. Fish fed increased levels of dietary choline, however, tended to have decreases in the hepatic somatic index; lipids, triglycerides, and cholesterol in liver; and triglycerides and cholesterol in serum. A decrease of lipid content in dorsal muscle was recorded in fish fed the diets containing choline >2.94 g kg−1. Additionally, dietary choline improved the reactions of fish to ammonia stress, including survival and behavioural responses, in fish fed diets containing choline levels >2.94 g kg−1. These findings indicate that choline plays important roles in lipid metabolism and stress tolerance in giant grouper. [ABSTRACT FROM AUTHOR]

The potential of Bacillus subtilis E20-fermented soybean meal ( FSBM) as a partial alternative component of fish meal ( FM) in fed diets of orange-spotted grouper ( Epinephelus coioides) was evaluated in this study. An FM-based diet and seven diets containing 10%, 20% and 30% and 10%, 20%, 30% and 40% of FM replaced by soybean meal ( SBM) and FSBM, respectively, were fed to grouper for 84 days to evaluate possible substitution levels of FM by tracking growth performance, digestive enzyme activity and morphological changes in the liver and distal intestine. No significant differences in survival and muscle composition of grouper were found between controls and treatments. Growth performance and feed efficiency of fish fed diets with FM replaced by FSBM up to 30% were not significantly different from controls, whereas significantly decreased growth performance and feed efficiency occurred with diets containing >20% of SBM. Based on the feed efficiency, the maximum substituted levels of FM by SBM and FSBM in grouper diets were 18.36% and 29.32%, respectively, based on broken-line analyses. Histopathological changes in the liver and distal intestine, and significantly lower activity levels of digestive enzymes, including pepsin in the stomach and trypsin, chymotrypsin, amylase and lipase in the distal intestine, were found in fish fed a diet containing 30% of FM replaced by SBM. However, these parameters were improved by the substitution of FSBM. It is therefore believed that FSBM has great potential to be used as a protein source in grouper diets in partial replacement of FM. [ABSTRACT FROM AUTHOR]

This study aimed to improve the nutritional value and utilization of soybean meal ( SBM) used as feed ingredient for shrimp by an approach of solid-state fermentation with Bacillus subtilis E20. The protein content and B. subtilis E20 proliferation significantly increased, as the initial moisture increased from 30% to 50% during fermentation. Compared with SBM, the protein content of FSBM increased by 19% after fermentation, accompanied by an increase of 18.75% in the total hydrolyzed amino acids. The free amino acid profile and content in FSBM also obviously increased by 374.9% compared with SBM. The FSBM is a good substitute for fish meal (FM) in a diet with 37% protein and 7% lipid content. The maximal replacement levels of FM in shrimp diet with SBM and FSBM were 37.42% and 61.67%, respectively, based on the feed efficiency estimated by a broken-line analysis. The B. subtilis E20- FSBM can be a potential protein source used as a replacement for FM in shrimp diet. [ABSTRACT FROM AUTHOR]

The purpose of this study was to use an electrolytic oxidizing ( EO) water system in a prawn hatchery. The results of the EO water generation efficiency showed that available chlorine in the EO water increased as the salinity and electric power increased, but was reduced as the water flow rate increased. A bactericidal activity assay showed that the growth of six aquatic pathogens was well inhibited by incubation with EO water containing 1 mg L−1 of available chlorine. The removal of NH3-N and NO2-N by electrolysis at 15‰ and 5 W had significant effects, and the removal rate of NO2-N was much faster than that of NH3-N. Prawn zoea ( Z) reared in EO water with different levels of available chlorine at 0 (control), 0.2, 0.3 and 0.4 mg L−1 had mortalities of 0%, 12%, 27% and 42%, respectively, after 72 h. However, Z were able to well survive in activated carbon-treated EO water for 1 week. For the on-farm use of the EO water system in a prawn hatchery, larvae in the EO water group had faster development and higher survival than those in the activated carbon group. From these results, we believe that the EO water group had excellent water quality and lower bacterial counts resulting in increased larval development and survival. [ABSTRACT FROM AUTHOR]