Development of a docosahexaenoic acid (DHA)-rich yellowtail <Emphasis Type="Italic">Seriola quinqueradiata</Emphasis> using tuna by-product oil

Because a diet rich in docosahexaenoic acid (DHA) is beneficial to human health, it is desirable for yellowtail Seriola quinqueradiata intended for human consumption to contain a high amount of DHA. We investigated the effects on the growth and fatty acid composition of yellowtail of replacing some of the pollack liver oil (PO) in the yellowtail diet with a DHA-rich tuna oil (TO). Experimental diets were prepared in which PO was replaced with 0, 15, 30, and 60% TO. Replacement of PO with TO did not negatively affect growth in a 16-week trial. In contrast, the feed efficiency of the group that received 60% TO was significantly higher than that of the control group after 6 weeks. The DHA level in the whole fish body increased with increasing dietary TO level. The groups that received 30 and 60% TO replacement diets showed significantly higher DHA levels than those of the control group. DHA level in the fillet was significantly higher in the group that received 60% TO than in the control group. DHA retention tended to increase with increasing TO level. These results show that utilizing TO as a fat source can increase DHA accumulation without incurring any adverse effects on the growth of yellowtail.     

Migratory history of the giant mottled eel (Anguilla marmorata) in the Bonin Islands of Japan

Chino N, Arai T. Migratory history of the giant mottled eel ( Anguilla marmorata ) in the Bonin Islands of Japan.
Ecology of Freshwater Fish 2010: 19: 19–25. © 2009 John Wiley & Sons A/S
Abstract –  In order to elucidate the migratory history and habitat use of the giant mottled eel Anguilla marmorata, in the Bonin Islands of Japan, strontium (Sr) and calcium (Ca) concentrations in otoliths were examined by X-ray electron microprobe analysis. The X-ray intensity map and line analyses showed three fluctuation patterns: (i) freshwater residence, (ii) continuous residence in brackish water, and (iii) residence in freshwater after recruitment, while returning to brackish water. Based on these results and previous studies, the migratory behaviours of A. marmorata appear to differ in each habitat in response to inter- and intra-specific competition. The results suggest that A. marmorata has a flexible pattern of migration, with an ability to adapt to various habitats and salinities.     

Effects of natural feeding stimulants and glutamic acid supplementation on the feed intake,growth performance and digestive enzyme activities of red sea bream (Pagrus major) fed fish meal‐free soy protein concentrate (SPC)‐based diet

Two experiments were conducted for red sea bream (Pagrus major). In experiment 1, the optimum level of glutamic acid and natural feeding stimulants to enhance feed intake were determined and found that glutamic acid level of 0.5% and fish meat hydrolysate (FMH) were effective. In experiment 2, fish were fed with soy protein concentrate (SPC)‐based diet with synthetic feeding stimulants (Basal diet), the Basal diet with FMH (FMH diet), the FMH diet with glutamic acid (FMHG diet) and with fish meal diet (FM diet) as a control until satiation for 8 weeks. Feed intake of FMHG‐fed fish was significantly higher than others (p < 0.05). Specific growth rate and the feed conversion ratio of FMHG were comparable to those of FM‐fed fish (p > 0.05). Relative visceral fat ratio and crude lipid content of any SPC‐based diet‐fed fish tended to be lower than those of FM diet‐fed fish. There were no significant differences in trypsin and lipase activities hepatopancreas among treatments. SPC can be utilized as a sole protein source in a diet for red sea bream. The lower growth performance in SPC‐based diet‐ fed fish was not due to poor digestive enzyme secretion but could be associated with lipid utilization disorder.     

Preliminary study on homing,site fidelity,and diel movement of black rockfish <Emphasis Type="Italic">Sebastes inermis</Emphasis> measured by acoustic telemetry

Several species of fish exhibit strong homing ability and distinct site fidelity to their original habitats and spawning sites. We have studied the homing ability, site fidelity, and diel movement patterns of three nocturnal black rockfish Sebastes inermis. The patterns were studied by radio-linked acoustic positioning system (VRAP) and fixed monitoring receivers (VR2) in Maizuru Bay, Japan from June to July 2004. All tagged fish were displaced by 80–120 m, but they returned to their respective captured sites at dusk, regardless of the time of release. The fish tagged with a depth sensor transmitter displayed active vertical movement just after the release, and subsequently swam near the bottom depth around the captured site. After homing, they displayed small home ranges [average 815 ± 265 m² (SD)] around a single rocky area with one or two core areas (average 64 ± 30 m²). One core area was utilized during the daylight and dark periods, whereas the other was used primarily during the dark period. The depth-tagged fish primarily used the depth of the rock crevice during the daylight, and it spent its dark period between the surface and the deeper bottom depth.     

Synthesis and Structure–Activity Relationships of Miticidal 4,5-Dihydropyrazole-5-thiones

A series of novel 4,5-dihydropyrazole-5-thiones (DHPs) was synthesised by treating the corresponding dihydropyrazolones with ‘Lawesson’s reagent and evaluated for miticidal activity against two-spotted spider mites (Tetranychus urticae Koch). Of these, 3-(4-chlorophenyl)-4,4-dimethyl-1-phenyl-4,5-dihydropyrazole-5-thione, 3-(4-chlorophenyl)-4-ethyl-4-methyl-1-phenyl-4,5-dihydropyrazole-5-thione, 3-(4-chlorophenyl)-1-phenyl-4,5-dihydropyrazole-5-thione-4-spirocyclopentane and 4,4-dimethyl-1-phenyl-3-(4-trifluoromethyl-phenyl)-4,5-dihydropyrazole-5-thione were highly active (pEC₅₀>4·0) and were more effective than the miticide dicofol (pEC₅₀=3·879), which has traditionally been used for the control of phytophagous mites. Structure–activity relationship (SAR) studies were performed on each position of the pyrazole ring of DHPs. The results indicated that the unsubstituted phenyl, 4-substituted phenyl and thioxo groups on the 1-, 3- and 5-positions of DHPs respectively were required for activity. Quantitative SAR studies using physicochemical parameters of substituents and the capacity factor k′ as a hydrophobicity index suggested that: (a) the activities of all types of DHPs examined were mainly dominated by hydrophobicity, (b) the bulkiness of 4-substituents of the 3-phenyl ring favoured the activity and (c) the log k′ optimum for all DHPs was 1·675, equivalent to a log P_ow value of c. 5·0.     

Low-fidelity homing behaviour of Biwa salmon <Emphasis Type="Italic">Oncorhynchus</Emphasis> sp. landlocked in Lake Biwa as inferred from otolith elemental and Sr isotopic compositions

Biwa salmon Oncorhynchus sp. is endemic to Lake Biwa, Japan, where it is an important commercial and recreational fisheries species. However, no information is currently available on its population structure and migration ecology. Therefore, here we evaluated whether otolith Sr/Ca, Ba/Ca and ⁸⁷Sr/⁸⁶Sr ratios can be used as natural signatures in Biwa salmon and then used these to determine the natal origins of lake-migration-phase individuals and spawning adults, and the homing ability of spawning adults in the Lake Biwa water system. Quadratic discriminant function analysis demonstrated that the lake-migration school comprised individuals with multiple origins, including rivers to the east, west and north of Lake Biwa, and that the homing rate of spawning adults was low (18 out of 80 individuals), with ca. 78% of fish straying into non-natal rivers. However, this straying behaviour was not spatially random, with fish tending to migrate upstream in rivers neighbouring their natal rivers. The high rate of straying in spawning adults is considered important for establishing and maintaining this species, which is highly adapted to life in the Lake Biwa water system where environmental disturbances often occur.     

Curious Oviposition Behavior in Phyllium westwoodii (Phasmatodea: Phylliidae): Preliminary Observations

We report that in a leaf insect, Phyllium westwoodii Wood-Mason (Phasmatodea: Phylliidae), two differing apertures can be used for oviposition, the color of eggs being affected by which aperture is used. Eggs which are forcibly propelled from the internal space within the valvulae of the abdomen are brown, whereas white eggs emerge slowly from the opening between the eighth sternite and the valvulae, and are deposited close to the ventral surface of the female. This unusual oviposition system does not appear to have been previously reported in phasmatids or in other insects.     

Pathological and phylogenetic features of prevalent canine distemper viruses in wild masked palm civets in Japan

Ten wild masked palm civets infected with canine distemper virus (CDV), captured in Japan from 2005 to 2007, were histopathologically and phylogenetically analyzed. Phylogenetic analysis based on the amino acid sequences of the H protein of two CDV isolates from masked palm civets revealed that the two isolates were classified into the clade of recent isolates in Japan. Histopathologically marked lesions of virus encephalitis were present in the brain, whereas gastrointestinal lesions were absent or at a mild degree. The distribution of the lesions resembles that of recent CDV cases in dogs. Therefore, recent CDV infections in masked palm civets could be caused by recently prevalent CDV in dogs. The possibility of the masked palm civet as a spreader of CDV among wildlife is also discussed.     

Effect of glimepiride and nateglinide on serum insulin and glucose concentration in healthy cats

Glimepiride and nateglinide are two common oral hypoglycemic agents currently being used with humans suffering from Type 2 diabetes mellitus. Neither drug has been tested with cats thus far and it is currently unknown whether either of these drugs exert any effect in cats or not. The objective of this study was to determine the effect of glimepiride and nateglinide on glucose and insulin responses in healthy control cats, in order to determine their potential use in diabetic cats. The intravenous glucose tolerance tests was carried out since it is an excellent test for evaluating pancreatic β-cell function for insulin secretion. Alterations in the insulin secretion pattern can be perceived as the earliest sign of β-cell dysfunction in many species, including cats. Nateglinide demonstrated a quick action/short duration type effect with serum glucose nadiring and insulin response peaking at 60 and 20 minutes, respectively. Alternatively, glimepiride is medium-to-long acting with serum glucose nadiring and insulin response peaking at 180 minutes and 60 minutes, respectively. Nateglinide’s potency was evident allowing it to induce a 1.5–2 higher preliminary insulin peak (3.7?±?1.1 pg/ml) than glimepiride’s (2.5?±?0.1 pg/ml), albeit only for a short period of time. Because glimepiride and nateglinide have a shared mode of action, no significant differences in overall glucose AUC_0-360min (24,435?±?2,940 versus 24,782?±?2,354 mg min/dl) and insulin AUC_0-360min (410?±?192 versus 460?±?159) in healthy control cats were observed. These findings may provide useful information when choosing a hypoglycemic drug suited for the treatment of diabetic cats depending on the degree of diabetes mellitus the cat is suffering from.