ABSTRACT
This study investigated the morphological, histological, and histochemical characteristics of the digestive tract of the marbled flounder (Pseudopleuronectes yokohamae). The relative length of the gut of the marbled flounder digestive tract was 1.54 ± 0.10 (n = 20), and it had a simple stomach and 6-9 pyloric caeca. The mucosal folds of the marbled flounder digestive tract exhibited a general branched morphology. The thickness and mucosal fold length of the intestinal muscularis externa showed similar aspects in all areas. The thickness of the intestinal muscularis externa was the thickest in the posterior intestine portion, and the length of mucosal folds was the longest in the anterior intestine portion. It was indicated that food digested by gastric acid in the stomach moves to the anterior portion (including pyloric caeca) and mid portion of the intestine, ensuring effective stimulation of cholecystokinin (CCK)-producing cells. In addition, the distribution pattern of CCK-producing cells in the intestine was very similar to that of mucus-secreting goblet cells. The CCK-producing cells and goblet cells in the marbled flounder were well-adapted to promote optimal control of the digestive process. Based on the morphological and histochemical studies, it was concluded that the marbled flounder displays a digestive tract comparable to that of fish species with carnivorous habits.
ABSTRACT
Although the mitochondrial genomes of most Acanthuriformes fish have been sequenced, this has not been done for Prionurinae fish yet. The Scalpel sawtail (Prionurus scalprum Valenciennes, 1835) found in all tropical and sub-tropical seas, is an important link between primary producers and higher trophic levels. In this study, the complete mitochondrial genome of the Scalpel sawtail, Prionurus scalprum Valenciennes, 1835 (accession number: OK323243) was sequenced. The complete mitochondrial genome included 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes, and a control region; the total length was 16,522 bp. The nucleotide composition of the genome was as follows: A, 28.46%; T, 27.62%; G, 16.46%; and C, 27.46%. All genes were encoded on the H-strand, except for the eight tRNA genes and NADH dehydrogenase subunit (ND6). A phylogenetic tree was constructed using the neighbor-joining (NJ) method and the phylogenetic position of the Scalpel sawtail was established. This provides useful data for future research on Acanthuridae fish.
ABSTRACT
The effect of feeding with taurine-enriched rotifers on larval growth and survival in the small yellow croaker Larimichthys polyactis was investigated. Rotifers, control (without taurine enrichment) or enriched with a commercial taurine supplement at two concentrations (400, and 800 mg/L), were used. The larvae (initial notochord length = 3.83 mm) were fed taurine-enriched rotifers in triplicate, from 3 days after hatching for 12 days. The average taurine contents of the rotifers were 0.31, 5.34, and 8.55 mg/g dry matter, respectively. The rotifers from all treatments had similar fatty acid composition. The growth and survival rates of the larvae fed rotifers enriched with 800 mg/L taurine supplementation were significantly higher than those of larvae fed rotifers without taurine enrichment (p = 0.005 and 0.002, respectively). The whole-body taurine content in the fish increased significantly with the increase in taurine level in the rotifers: 1.02, 3.48, and 4.11 mg/g in larvae fed control rotifers, and rotifers enriched with 400, and 800 mg/L taurine supplementation, respectively. The results of this study indicate that small yellow croaker larvae benefit from taurine concentrations above those typically reported in non-taurine-enriched rotifers.
ABSTRACT
An 8-week feeding trial was conducted to determine the optimal dietary protein level for juvenile marbled flounder. Five semi-purified test diets were formulated to contain different protein levels (CP) including 42.7%, 47.4%, 53.3%, 58.8%, and 64.5% (dry matter), named as CP42.7, CP47.4, CP53.3, CP58.8, and CP64.5, respectively. Five hundred and twenty-five juveniles (6.0 ± 0.1 g) were randomly distributed into 15 tanks (300 L tanks), resulting in 35 fish per tank (n = 3 tanks). Fish were fed the test diets 5 times per day until satiation. The CP58.8 resulted in the highest gain in weight and the best efficiency in feed utilization among the tested protein levels (P < 0.05). Fish fed the CP58.8 diet showed significantly higher whole-body protein and lipid contents than the fish that were fed the other diets (P < 0.05). Fish fed the CP53.3, CP58.8, and CP64.5 diets showed a significantly higher dorsal-muscle lipid content than the fish that were fed the CP42.7 and CP47.4 diets (P < 0.05). The one-slope straight broken-line regression analysis on the results of the thermal growth coefficient and feed conversion ratio indicated that the estimated optimum dietary protein level was 58.8%. Taken together, it is suggested that the dietary protein level of 58.8% is optimal for better growth and high efficiency in feed utilization for the juvenile marbled flounder.
ABSTRACT
BACKGROUND/AIMS: Few studies have evaluated the use of a smartphone application (app) for educating people undergoing colonoscopy and optimizing bowel preparation. Therefore, this study was designed to develop a smartphone app for people to use as a preparation guide and to evaluate the efficacy of this app when used prior to colonoscopy. METHODS: In total, 142 patients (male:female=84:58, mean age=43.5±9.3 years), who were scheduled to undergo a colonoscopy at Myongji Hospital, were enrolled in this study. Seventy-one patients were asked to use a smartphone app that we had recently developed to prepare for the colonoscopy, while the 71 patients of the sex and age-matched control group were educated via written and verbal instructions. RESULTS: The quality of bowel cleansing, evaluated using the Boston Bowel Preparation Scale, was significantly higher in the smartphone app group than in the control group (7.70±1.1 vs. 7.24±0.8, respectively, p=0.007 by t-test). No significant differences were found between the two groups regarding work-up time and the number of patients with polyps. CONCLUSIONS: In this study, targeting young adults (≤50 years), the bowel preparation achieved by patients using the smartphone app showed significantly better quality than that of the control group.
