Food safety,livestock health,and productivity of a dairy farm following implementation of a certificated Hazard Analysis and Critical Control Points system

This study examined the safety and productivity data analysis of a dairy farm over a 3-year period following the implementation of a Hazard Analysis and Critical Control Point (HACCP) system in 2018. The CCP was “the selection of milking cows” and the critical limit was “the withholding period has passed”. No deviation from the critical limit was observed, the safety of the milk is ensured. In addition, the average daily milk yield per cow increased, while the average number of somatic cells/ml decreased. The number of cows with newly diagnosed mastitis increased, and the product excluded. These results suggest that the HACCP system had a positive effect on milk yield per cow and led to a decrease in somatic cells.     

Development of phototaxis in the early life stages of Pacific bluefin tuna <Emphasis Type="Italic">Thunnus orientalis</Emphasis>

We investigated the development of phototaxis in larval and early juvenile stages of Pacific bluefin tuna Thunnus orientalis to detail behavior development in relation to light. We observed the distribution of Pacific bluefin tuna in an illumination gradient tank from 1 to 26 days after hatching (DAH). Two long rectangular tanks (100 × 10 × 10 cm) were used for experiments; each tank was divided into four sections for observations and one tank was equally illuminated at 1.0 × 10³ lx as the control tank, and the other was at 4.0 × 10², 1.0 × 10³, 1.0 × 10⁴ and 7.0 × 10⁴ lx as the illumination gradient tank. Laboratory-reared larvae and juvenile were released into each tank and acclimatized for 10 min. Thereafter, the number of individuals in each section was counted for 5 times with 10-min intervals. Until 2 DAH (3.6 ± 0.1 mm BL), larvae distributed homogeneously in each section in both tanks. After 3 DAH (3.7 ± 0.1 mm BL) when the eyes of the larvae were pigmented, most fish moved into the 7.0 × 10⁴ lx section in the illumination gradient tank, while fish in the control tank maintained a uniform distribution during the experimental period (Chi-square test, P < 0.05). The results suggest that the post-larvae and juvenile stages show strong positive phototaxis.     

Morphological identity of a taxonomically unassigned cytochrome c oxidase subunit I sequence from stomach contents of juvenile chum salmon determined using polymerase chain reaction

In a previous report, we analyzed the stomach contents of juvenile chum salmon Oncorhynchus keta by morphological observation and also by molecular identification using the mitochondrial cytochrome c oxidase subunit I (COI) region. However, one of the most frequently detected COI sequences could not be assigned to any specific taxon, even at the phylum level. In the present study, we conducted in situ hybridization (ISH) on the stomach contents of juvenile chum salmon using the COI sequence and polymerase chain reaction amplification of a 18S ribosomal RNA gene from the tissue sections where ISH signals were detected. As a result, the organism that was enigmatic at the phylum level was found to be an appendicularian. Moreover, Oikopleura longicauda collected from the bay where the juvenile chum salmon samples were obtained was shown to have the same COI sequences as this taxonomic “orphan” COI sequence from the stomach contents. The present results suggest that the COI sequences previously deposited in public databases for “Oikopleura” are actually derived from taxonomic groups other than appendicularians, and that this may have hampered our understanding of prey richness in the stomach or gut of certain marine animals based on DNA barcoding.     

Effect of a Wheat Protein on pH-Dependent Water-Binding Capacity and Viscosity of Wheat Tailings Fractions

Wheat flour was fractionated with acetic acid using a mortar and pestle method or a blender method. Higher pH-dependent water-binding capacity (WBC) and viscosity were obtained only in the tailings fraction. The higher pH-dependent WBC was rather stable at 5–37°C, however it decreased with salt addition. Pepsin or bromelain treatment stopped the pH-dependent changes in WBC and viscosity, which suggests that this characteristic of the tailings fraction is due to the presence of proteins. HPLC indicated that the M_r of the proteins associated with high WBC at low pH was >200 kDa.     

Effects of double harvesting on estimated total digestible nutrient yield of forage rice

We examined the effects of cultivar (Taporuri, Mohretsu, Tachiaoba, and Hinohikari) on estimated total digestible nutrient (TDN) yield of forage rice in double harvesting. The total estimated whole-plant TDN yield (i.e., of the first crop plus second crop) of Taporuri was the highest in double harvesting. In the first crop, the estimated whole-plant TDN yield of Taporuri was the highest. In the second crop, the estimated whole-plant TDN yield of Taporuri was almost the same as those of Mohretsu and Tachiaoba but higher than that of Hinohikari. We also examined the effects of cultivation method (double harvesting or single harvesting) on estimated TDN yield of forage rice. In Taporuri and Mohretsu, the total estimated whole-plant TDN yield was similar in double harvesting and single harvesting. However, in Tachiaoba and Hinohikari, it was lower in double harvesting than in single harvesting. It is important to maximize the amount of nutrition in leaf and stem rather than panicle because the grain is not digested well by cattle. In the double harvesting, the total estimated leaf blade (leaf) TDN yield of Taporuri was higher than that of Hinohikari and almost the same as those of Tachiaoba and Mohretsu. The total estimated leaf sheath plus stem (stem) TDN yield of Taporuri was the highest. In comparison of the total TDN yield of double harvesting with that of single harvesting, the total estimated leaf and stem TDN yields were higher in double harvesting than in single harvesting in all cultivars except for Hinohikari. Thus, double harvesting of Taporuri is an effective way of reducing the overall loss of nutrition from the crop.     

Vortex flow produced by schooling behavior of arabesque greenling <Emphasis Type="Italic">Pleurogrammus azonus</Emphasis>

Arabesque greenling Pleurogrammus azonus form schools of 30,000–60,000 individuals to feed on mesozooplankton near the sea surface. The fish need to be close to the surface where mesozooplankton production occurs, but the food is not sufficiently dense there for the fish to grow optimally while avoiding predation by sea birds. Arabesque greenling use a unique method to optimize their feeding conditions while avoiding staying on the sea surface. When the school swims upward, water is pushed downward. Upward swimming of a school of 30,000 individuals generates a downward stream of about 0.8–1.1 m/s, resulting in a convergent flow near the surface. This convergence concentrates the mesozooplankton on the sea surface and transports them into deeper layers with a strong vortex about 3.0 m in diameter and 10–20 m long. Thus, schooling of this fish induces vortex flows that provide a rich feeding environment.     

Effect of Initial Stocking Density on Larviculture Performance of the Ocellate Puffer,Takifugu rubripes

Depending on the initial stocking density, ocellate puffer larvae exhibit the cannibalism that resulted in high mortality. We aimed to clarify the relationship between stocking density of larvae, mortality, and the effect of density on cannibalism. Ocellate puffer larvae were reared at five different stocking densities between 5 and 25 larvae/L with duplicate 1‐m³ tank for each treatment. Larvae were stocked at 0 d after hatch (d.a.h.), and the experimental cultures lasted for 55 d. In larvae stocked initially at more than 10 larvae/L, cannibalism was evident from 11 to 17 d.a.h., and the survival rate at 55 d.a.h. was less than 15%. The survival rate was 25.5% at 5 larvae/L, and cannibalism was observed from 31 to 32 d.a.h. Consequently, an initial density of 5 larvae/L was the most efficient in terms of survival and the prevention of cannibalism. On the other hand, when cannibalism is still observed at 5 larvae/L, it is necessary to lower the stocking density before the onset of cannibalism.     

Induction of larval metamorphosis in the sea cucumber Apostichopus japonicus by neurotransmitters

Larval metamorphosis inducers of the sea cucumber Apostichopus japonicus were screened from physiologically active compounds. Doliolaria larvae completed their metamorphosis to juveniles in 120 h when treated with 5–10 μM of dopamine and l-DOPA, and 50 μM of l-adrenaline and l-noradrenaline. Doliolaria larvae had to be exposed to dopamine or l-DOPA for at least 24 h. D1-like dopamine receptor antagonists SKF87566 and LE300 (10 μM) inhibited metamorphosis by dopamine. However, the D2-like dopamine receptor antagonists sulpiride and nemonapride (10 μM) did not inhibit the effect of dopamine. The results suggest that D1-like dopamine receptors are involved in larval metamorphosis of the sea cucumber A. japonicus.