Masayuki Furuichi

Essentiality of dietary calcium supplement in / fingerling scorpion fish Sebastiscus marmoratus

Abstract Essentiality of dietary calcium (Ca) supplement was investigated in fingerling scorpion fish. Four purified diets were formulated with supplementation of 0.2% Ca from Ca-lactate, no supplemental Ca, and 0.2 and 2.5% Ca from tricalcium phosphate (TCP), respectively. Each experimental diet was fed to three replicate groups of fish (mean weight, 0.8 g) for 12 weeks at a water temperature of 24±0.2°C. Significantly lower weight gain was observed in fish fed the Ca-unsupplemented diet compared to the control diet with 0.2% Ca supplement from Ca-lactate. The growth of fish fed the diet with a low level (0.2%) of Ca from TCP was similar to that of fish fed the control diet. However, a high level (2.5%) of dietary Ca from TCP significantly decreased growth. Calcium and phosphorus contents in whole body and vertebrae were similar in fish fed all the diets. A high level of dietary Ca from TCP decreased some trace elements in whole body, liver and vertebrae. Results suggest that scorpion fish do not obtain adequate Ca from seawater for normal growth and a dietary Ca supplement is necessary. Although this species can use a low level of dietary TCP as a source of Ca for growth, excessive dietary TCP depresses growth and negatively affects the contents of some trace elements in tissues. Readily available Ca (mono- or dibasic Ca) supplement to the diet appears to be essential for optimum growth and for maintaining normal mineral levels in tissues of scorpion fish.

Availability of environmental and dietary calcium in tiger puffer

Tiger puffer, Takifugu rubripes, juveniles were fed with four semi-purified experimental diets containing 0.2% Ca from Ca-lactate (diet 1), no supplemental Ca (diet 2) and 0.2% and 2.5% Ca from tricalcium phosphate, TCP (diets 3 and 4), respectively. After a 10 week rearing period, growth and feed utilization were significantly lower in the fish group fed on diet 2 than in the fish group fed on diet 1. Fish groups fed on diets 3 and 4 also showed poor growth performances compared with group 1. It appears that Ca intake from seawater is not sufficient for the normal growth of tiger puffer. Furthermore, Ca in dietary TCP appeared to be unavailable to this species. Dietary TCP strongly inhibited the bone mineralization of Zn and Mn. The findings indicate that easily digestible Ca supplementation is indispensable in a diet of tiger puffer for normal growth, feed utilization and bone mineralization.

Occurrence of Nα-acetylhistidine in the muscle and deacetylation by several tissues of nile tilapia (oreochromis niloticus)

Abstract 1. 1. Nα- Acetyl - l - histidine was identified in protein-free extracts of muscle of Nile tilapia ( Oreochromis niloticus ), and this substance was the major component (2.8 μmol/g tissue) of the imidazole pool in the muscle of the fish. 2. 2. High Nα -acetylhistidine-deacetylating activity was found in crude enzyme solutions prepared from kidney, brain, liver and eye of the fish, and kidney was the richest source of this activity. 3. 3. After intraperitoneal administration of Nα -acetylhistidine to the fish, a drastic increase in kidney histidine concentration was observed after 2 hr. 4. 4. It is supposed that exogenously administered Nα -acetylhistidine is transported to kidney via blood plasma, and effectively deacetylated to histidine by the enzyme(s) of the kidney.

Effects of starvation and feeding on tissue Nα-acetylhistidine levels in Nile tilapia Oreochromis niloticus

Abstract The effects of long-term starvation and feeding on N α, -acetylhistidine (NAcH) levels in skeletal muscle, brain and lens of Nile tilapia Oreochromis niloticus were examined. A drastic decrease in NAcH level of skeletal muscle during starvation was observed. This compound disappeared from skeletal muscle of the fish after 8 weeks of starvation, and was completely restored to the pre-starvation level (4–5 μmol/g muscle) by the following 8 weeks of feeding. The activities of N -acetylhistidine deacetylase (NAcHDE) and histidine acetyltransferase (HISAT) were very weak, but detectable in skeletal muscle of the species. It is supposed that the change of the NAcH level in skeletal muscle during starvation and feeding appears as a result of the degradation by NAcHDE and of the synthesis by HISAT.

Properties of Nα-acetylhistidine deacetylase in brain of rainbow trout Oncorhynchus mykiss

Abstract 1. 1. Nα -Acetylhistidine deacetylase was purified from the brain of rainbow trout to apparent homogeneity. 2. 2. The brain and eye deacetylases are the same metalloenzyme which is a dimeric protein with a subunit of 55 kDa. 3. 3. The deacetylase showed strong activity against Nα- chloroacetyl - l - leucine and glycyl- l -leucine. Anserine, carnosine and homocarnosine were poorer substrates than Nα- acetyl - l - histidine and tripeptides tested were unable to be hydrolyzed. 4. 4. High activity of the deacetylase was found in all regions of the trout brain except for the spinal cord and the optic nerve. In subcellular fractionation, 90% of the total deacetylase activity was recovered in the soluble supernatant fraction, whereas a large proportion (40%) of the total endogenous acetylhistidine occurred in the crude mitochondrial pellet.

PARTIAL PURIFICATION AND CHARACTERIZATION OF HISTIDINE ACETYLTRANSFERASE IN BRAIN OF NILE TILAPIA (OREOCHROMIS NILOTICUS)

High activity of histidine acetyltransferase (HISAT) was found in the brain and the lens of Nile tilapia Oreochromis niloticus. HISAT was semi-purified 4166-fold from the brain of Nile tilapia. The affinity chromatography using a Blue Sepharose 6 FF column was very effective for purification of this enzyme. The enzyme had a broad pH optimum from pH 7.0 to pH 9.5, and did not require any divalent metal ion. The semi-purified HISAT showed a strict substrate specificity for L-histidine (and its methyl derivatives) and acetylcoenzyme A (CoASAc). The reaction velocity fits normal Michaelis-Menten kinetics with respect to both L-histidine (Km, 0.45 mM) and CoASAc (Km, 0.027 mM). Gel filtration on Superdex 200 HR indicated the molecular weight of 39,000. It was presumed that the 38.5 kDa protein, which was intensely visualized in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was a single subunit derived from HISAT.

Nα-acetylhistidine metabolism in fish—I. Identification of Nα-acetylhistidine in the heart of rainbow trout Salmo gairdneri

Abstract Nα- Acetyl- l -histidine was isolated from protein-free extracts of heart of rainbow trout Salmo gairdneri , and the identification was determined by the use of mass and infrared spectrometer.

Calcium Requirement of Tiger Puffer Fed a Semi-Purified Diet

Juvenile tiger puffer (Takifugu rubripes) were fed semi-purified diets with graded levels (0–0.40%) of calcium (Ca) supplements for 8 weeks at a temperature of 23.0–25.5 °C. At the end of the feeding experiment, average final body weight increased with increasing dietary Ca levels. A diet without Ca supplement resulted in poor average final body weight and 0.05% dietary Ca supplement could not significantly improve the growth. However, supplemental Ca levels of 0.10–0.40% significantly increased growth. Dietary Ca supplements of 0.10% or more also improved the feed efficiency in tiger puffer. Ca and phosphorus contents of the bone were independent of dietary Ca supplements. However, 0.40% Ca in the diet decreased the zinc and manganese contents of bone. Results indicated that supplemental Ca levels of 0.10–0.20% in a semi-purified diet were required to maintain normal growth, feed utilization and bone mineralization of tiger puffer.

Fatty acid composition and dietary value of rotifer Brachionus plicatilis fed on waste lipid treated with Aspergillus terreus

Attempts were made to improve the dietary value of rotifer fed on bakers yeast by direct feeding of microbial-treated lipid. The nontreated lipid (NTL) from mackerel waste juice was treated with Aspergillus terreus, and the treated lipid (TL), NTL and pollack liver oil (PLO) were emulsified with sea water and proteinous sediment from the waste juice. The emulsified lipids and yeast were fed to rotifers and the proximate and fatty acid compositions of the rotifers were determined. Furthermore, ayu larvae were reared with the rotifers fed on bakers yeast (BY) with or without TL or NTL, and their growth and survival rate were compared. The rotifers fed on the lipids showed similarly higher lipid content than the initial rotifer. However, the ω3 HUFA content of rotifer fed on TL (BY+TL rotifer) was higher than that of the rotifer fed on NTL (BY+NTL rotifer) and similar to rotifer fed on PLO (BY+PLO rotifer). The total body length of larvae reared with BY+NTL rotifer (BY+NTL group) was significantly inferior to that of BY+TL group at the end of the 25 days feeding trial.The survival rates of BY+NTL group in feeding trial and handling tests were also lower than those of BY+TL group. The larvae reared with rotifer fed on BY only were the lowest of all the groups in the growth and survival rate.

Microbial treatment of liquid from mackerel waste juice

Yeast Saccharomyces cerevisiae IFO 2114 was cultured in 25l of 75% sea water containing liquid obtained from mackerel waste juice and molasses (WY) for 48h, and (1) nitrogen and pho-sphorus contents in WY medium and (2) proximate and fatty acid compositions of the harvested yeast (WY yeast) were determined. The amount of harvested WY yeast was sufficient to feed rotifers (150×106 indiv./ton) for a day. Furthermore, the yeast reduced nitrogen and phosphorus contents in the medium to a level which was considered to be safe to discard. On the other hand, WY yeast was higher than yeast cultured in MY medium and bakers yeast and far lower than ω yeast and marine chlorella in lipid content and percentage of ω3 HUFA in total fatty acids.