Effect of a plant-based low-fishmeal diet on digestive physiology in yellowtail Seriola quinqueradiata

To characterize the effects of a plant-based low-fishmeal (LFM) diet on the digestive physiology of yellowtail, Seriola quinqueradiata, we prepared two isonitrogenous and isolipidic diets; an FM-based diet (diet Control, FM 50%) and a plant protein (soybean meal and corn gluten meal)-based low fishmeal diet (diet LFM, FM 15%), and examined the acute and chronic effects of the diets on the digestive physiology of the fish were examined. In the acute effect trial (fed only a single meal), the fish fed the LFM diet displayed faster gastric emptying, lower pH of the gastrointestinal content and suppressed pancreatic digestive enzymes (trypsin, chymotrypsin and amylase) secretions. In the chronic effect trial (feeding for six weeks), in addition to the effects observed in the acute trial, the fish fed the LFM diet also displayed suppressed stomach pepsin secretion and pancreatic digestive enzymes production (gene expression). Furthermore, gene expression levels of digestion-regulating hormones, gastrin, cholecystokinin and peptide yy were also disrupted by the long-term administration of the LFM diet. Taken together, these results indicate that a plant protein-based low fish meal diet appears to not fully activate or stimulate the digestive system of yellowtail in either the short or long term and that its inhibitory/disruptive effects become more pronounced on a long-term basis. The effects we have identified on yellowtail digestive physiology could serve as important indicators to improve the plant-based low-fishmeal diets

Effect of a plant-based low-fishmeal diet on digestive physiology in yellowtail Seriola quinqueradiata

To characterize the effects of a plant-based low-fishmeal (LFM) diet on the digestive physiology of yellowtail, Seriola quinqueradiata, we prepared two isonitrogenous and isolipidic diets; an FM-based diet (diet Control, FM 50%) and a plant protein (soybean meal and corn gluten meal)-based low fishmeal diet (diet LFM, FM 15%), and examined the acute and chronic effects of the diets on the digestive physiology of the fish were examined. In the acute effect trial (fed only a single meal), the fish fed the LFM diet displayed faster gastric emptying, lower pH of the gastrointestinal content and suppressed pancreatic digestive enzymes (trypsin, chymotrypsin and amylase) secretions. In the chronic effect trial (feeding for six weeks), in addition to the effects observed in the acute trial, the fish fed the LFM diet also displayed suppressed stomach pepsin secretion and pancreatic digestive enzymes production (gene expression). Furthermore, gene expression levels of digestion-regulating hormones, gastrin, cholecystokinin and peptide yy were also disrupted by the long-term administration of the LFM diet. Taken together, these results indicate that a plant protein-based low fish meal diet appears to not fully activate or stimulate the digestive system of yellowtail in either the short or long term and that its inhibitory/disruptive effects become more pronounced on a long-term basis. The effects we have identified on yellowtail digestive physiology could serve as important indicators to improve the plant-based low-fishmeal diets

Onboard rearing attempts for the Japanese eel leptocephali using POM-enriched water collected in the Western North Pacific

Hatchery produced leptocephalus larvae of the Japanese eel (Anguilla japonica) were reared on a research vessel and fed natural particulate organic matter (POM) collected in the Western North Pacific. A small net (36 cm diameter, 60 µm mesh) was vertically towed from 200 m depth to surface in 2013, and POM-enriched water (POMEW) filtered through 350 µm mesh was fed to the leptocephali for 11 days. Although the swollen gut corroborated the active ingestion of POM by the leptocephali, low survival rate and heavily melanized gut followed by necrosis in the mid-hindgut region of the leptocephali were observed. A large net (1.14 m diameter, 30 µm mesh) was used in 2014 and 2015, which was horizontally drifted subsurface (100–175 m). POMEWs filtered through 53 or 25 µm meshes were fed to the leptocephali for 5–18 days. Neither melanized gut nor necrosis occurred, but considerably low survival rate and little growth comparable with that in a starved condition were observed. No apparent shift in stable carbon and nitrogen isotope ratios was observed in the reared leptocephali. These indicated that the ingested POMs were not assimilated by the leptocephali and suggested that smaller particles may be important for the leptocephali

Effect of dietary taurine and cystine on growth performance of juvenile red sea bream Pagrus major

Two experiments were conducted to investigate the effect of dietary taurine and cystine on growth and body composition of juvenile red sea bream Pagrus major. In Experiment I, a casein-based semi-purified diet included a small amount of fish meal were supplemented with taurine at the levels of 0 (control) and 1.0%. The experimental diets in Experiment II were without fishmeal and supplemented with taurine at 0 (control), 0.5, 1.0 and 2.0% or cystine at 1.0 and 2.0%. These diets were fed three times a day for 6 weeks to fish (average body weight: 2.3 g in Experiment I and 2.5 g in Experiment II). In Experiment I, fish fed the taurine-supplemented diet showed significantly (P < 0.05) improved growth, feed efficiency and feed consumption relative to fish fed the unsupplemental diet. The whole body taurine content increased, whereas the non-essential amino acid contents decreased, in fish fed the taurine-supplemental diet compared to fish fed the unsupplemented diet. In Experiment II, the growth, feed efficiency and feed consumption of fish fed the taurine-supplemented diets, irrespective of the dietary taurine levels, were significantly higher than those of fish fed the control diet and the cystine-supplemented diets. Taurine content in the whole body increased with the dietary taurine level, while the taurine contents did not increase by the supplemental cystine. Other free amino acid contents in the taurine-supplemented diet groups followed similar trends to those in Experiment I. These results indicate that supplemental taurine to a casein-based semi-purified diet at more than 0.5% improved the growth and feed performance of juvenile red sea bream. It is also suggested that juvenile red sea bream cannot metabolize cystine into taurine

A new computerized assessment battery for cognition (C-ABC) to detect mild cognitive impairment and dementia around 5 min.

This study aimed to develop a new computerized assessment battery for cognition (C-ABC) to detect mild cognitive impairment (MCI) and dementia. We performed C-ABC in subjects with dementia (n = 422), MCI (n = 145), and normal cognition (NC; n = 574), and analyzed by age stratum (50s, 60s, and 70-85 years). To distinguish MCI from NC, the C-ABC total combined score, which were calculated by dividing the C-ABC total score by the C-ABC required time, revealed the best area under the curves (AUC) at 0.838 and 0.735 in the 50s and 60s age groups, respectively; notably, this entire procedure took approximately 5 min. To distinguish dementia from NC and MCI, the partial items of C-ABC (items 3 + 6 combined score) revealed the best AUCs at 0.910, 0.874, and 0.882 in the 50s, 60s, and 70-85 age groups, respectively. Furthermore, the items 3 + 6 combined score established the best AUC at 0.794 in the 70-85 age group to distinguish MCI from NC; this entire procedure took around 2 min. Hence, this study suggests that C-ABC could be a useful tool for detecting dementia or MCI in a short time