A numerical study on the transport of eggs and larvae of Sergia lucens in Suruga Bay,Japan

Numerical experiments were performed to investigate the transport processes of eggs and larvae of Sergia lucens in Suruga Bay, Japan, focusing on the physical effects of the river water spreading. In the experiments, labeled particles, which were regarded as the eggs or early larvae of S. lucens with no (or weak) swimming ability, were passively transported in flow fields that were calculated by an ocean general circulation model. In the innermost region of the bay (off the Fuji River mouth) where there is no continental shelf, a retention area where the eggs and larvae could stay in a nutrient‐rich environment for a long time was formed, especially in the upper part of their habitation layers, by the large bulge with anticyclonic (clockwise) circulation. No retention area was formed in the western region of the bay (off the Oi and Abe River mouths) or in an additional experiment in which a continental shelf was artificially created in the innermost region. It was estimated that in the retention area, the residence time of the eggs and early larvae is prolonged by about a month. The formation of the retention area is controlled by the dynamics of the river water spreading, affected by the bottom topography and the Earth’s rotation. Moreover, the reason why S. lucens are only caught in abundance in Suruga Bay was discussed.     

Evaluation of novel sulfonylurea derivatives with a fused heterocyclic moiety as paddy herbicides that control sulfonylurea‐resistant weeds

Herbicidal activity and acetolactate synthase (ALS) inhibition of sulfonylurea derivatives with a fused heterocyclic moiety bonded to a sulfonyl group were investigated. Some compounds that had an imidazo[1,2‐b]pyridazine moiety substituted at the 2‐position by chlorine or methyl controlled sulfonylurea‐resistant (SU‐R) weeds and showed inhibitory activity to ALS prepared from SU‐R Schoenoplectus juncoides shoot. There was a correlation between in vitro and whole‐plant herbicidal activity of the compounds mentioned above against SU‐R Schoenoplectus juncoides. Among them 1‐(2‐chloro‐6‐propylimidazo[1,2‐b]pyridazin‐3‐ylsulfonyl)‐3‐(4,6‐dimethoxypyrimidin‐2‐yl)urea, propyrisulfuron, was selected for further evaluation. Propyrisulfuron effectively controlled paddy weeds at doses of 70 and 140 g a.i. ha^?1 with good rice selectivity in a field trial.     

Age-related changes in leukocytes and T cell subsets in peripheral blood of Japanese Black cattle

It is well known that the immune system changes with age during development and maturation in Holstein cattle. But age-related changes in leukocytes and T cell subsets in peripheral blood of Japanese Black cattle still remain unclear. The aim of the present study was to investigate comparative changes of leukocytes (granulocytes, monocytes, B cells and T cells) and T cell subsets (CD4⁺, CD8⁺, γδ, CD8⁺γδ and WC1⁺γδ T cells) in Japanese Black cattle aged 0.5, 1, 2, 6, 18 and 36–41 (adult) months on flow cytometry using specific monoclonal antibodies for the cell surface markers. T cell proportion was approximately 40% in 2-month-old cattle and decreased to 20.6% in adults. In contrast, B cell proportion significantly increased from 7.4% to 28.2% with age. In T cell subsets the percentage of CD4⁺ T cells significantly increased from 40.5% to 60%, but that of WC1⁺γδ T cell subset significantly decreased with age. The percentages of CD8⁺ and CD8⁺γδ T cells did not change. The present study details the proportional changes in leukocyte and T cell subsets with age in the peripheral blood of Japanese Black cattle and these findings are similar to those described for Holstein cattle.     

Calming effect of orally administered γ‐aminobutyric acid in Shih Tzu dogs

The calming effects of γ‐aminobutyric acid (GABA) by oral administration were investigated in four adult Shih Tzu dogs. Three dosage levels (1, 2 and 4 mg/kg body weight) and non‐administration were tested by an increase and decrease method. Changes in activity (for 1.5 h) and urinary cortisol levels (pre‐administration, 3 and 7 h later) of dogs were monitored after administration. Without reference to dosage level, the mean times spent standing (P = 0.06), sitting (P < 0.05) and walking (P < 0.05) tended to decrease compared to non‐administration. A significant depression in the urinary cortisol level was observed at 7 h after administration (P < 0.05). These results indicate that orally administrated GABA exerts calming effects on dogs as well as humans.     

Effects of forage-to-concentrate ratio in prepartum diet on the dry matter intake and milk yield of periparturient cows during hot weather

The objective of this experiment was to study the effect of prepartum diets on dry matter intake (DMI) around parturition and on milk production in early lactation during a hot summer. Nine cows due to calve in July or August were assigned to two groups and fed either control (group C; four cows) or high‐concentrate (group H; five cows) diets to meet 110% of their energy requirements from 18 days before the expected calving date to parturition. The proportion of concentrate in the control diet was 35%, and that in the high‐concentrate diet was 45%. For 21 days after parturition, all cows were fed the same diets for lactation ad libitum. The DMI of cows in group H almost met their energy requirements. In group C, the DMI was decreased relative to group H and the concentration of plasma non‐esterified fatty acids was significantly higher (P < 0.05) before parturition. Therefore, the cows in group C were thought to be energy deficient before parturition. After parturition, there were no significant differences in DMI between the two groups. The milk yield of cows in group H tended to be higher than that of cows in group C at 21 days after parturition. Milk protein yield was significantly higher (P < 0.05) in group H 21 days after parturition relative to group C. There were no significant differences in milk composition between the two groups.     

The novel polymorphism of the beta 3-adrenergic receptor gene and its distribution in domestic pigs and wild boars in Asia

The beta 3‐adrenergic receptor (ADRB3) is a G protein‐coupled receptor that is involved in regulating energy homeostasis. We have studied DNA sequences of porcine ADRB3 to find candidate genetic polymorphisms for economically important growth and performance traits in pigs. Five novel haplotypes derived from the three In/dels and 44 SNPs were identified among domestic pigs and wild boars. Three of them encode non‐synonymous amino acid sequences by five missense polymorphisms and a frameshift by a thymine insertion. The amino acid polymorphic sites were distributed as follows: one substitution was in extracellular loop 1, three substitutions were in intracellular loop3 and one substitution and the deletion of two amino acids were at the carboxyl‐terminal. There was no polymorphism in the transmembrane domains. In addition, we surveyed the allelic frequency of the thymine insertion that cause frameshift in South‐east Asian local pigs, including some commercial breeds and wild boars. This thymine insertion was distributed widely in the domestic pigs and wild boars. The frequencies of this allele were relatively low in Western improved breeds, while they were very common in Asian breeds and wild boars in Asia. This result indicates that this insertion originally occurred in ancient Asian wild boars and then circulated among Asian domestic pigs. This allele also spread over Western breeds, probably through the introgression of Asian pigs into European stocks during the 18th and 19th centuries.     

Flight distance of dairy cows and its relationship to daily routine management procedures and productivity

The objectives of this study were to determine to what extent the flight distance of cows to humans was influenced by sire and management procedures before and after maturity, and whether there was a correlation between the flight distance and productivity on commercial dairy farms. Flight distance of 84 Holstein cows, the stockperson's daily routine management procedures and production performance were recorded repeatedly on eight commercial dairy farms. The management procedures for the animals at the suckling, growing, lactating and dry stages were classified into four categories by degree of tactile interactions between the stockperson and the animal: hand procedures with touch on (category A), nearby (category B) and apart (category C) from the animal, and machinery procedures (category D). There was no apparent sire effect on flight distance ( P  = 0.08), whereas the flight distance ranged from 1.17 ± 0.86 to 4.47 ± 2.01 m by farm ( P  < 0.01), and gradually shortened with repetition ( P  < 0.05). Regression analysis indicated that the length of time of category B at the suckling stage and category B at the dry stage accounted for 37% and 32% of the variation in flight distance, respectively. As for the total time of the four procedure categories, growing stage was the prime predictor of flight distance, which accounted for 36% of the variation. Flight distance tended to correlate with the first calving age ( r  = 0.66, P  = 0.07). These results suggest the importance of non-producing periods, before maturity and during the dry period, on the subsequent and lifelong advantages of a good relationship between the stockperson and their animals.     

Ruminal distribution of the cellulolytic bacterium Fibrobacter succinogenes in relation to its phylogenetic grouping

To investigate the ecological importance of the cellulolytic bacterium Fibrobacter succinogenes in fiber digestion, ruminal distribution of F. succinogenes was determined in relation to its phylogenetic grouping. Rumen digesta from wethers and steers fed orchardgrass hay, rice straw or fresh orchardgrass were employed as the materials for the analyses. Orchardgrass hay stem incubated in the rumen was also used. By using total DNA extracted from these materials, population sizes of total F. succinogenes and of four different phylogenetic groups of this species were quantitated through competitive polymerase chain reaction (PCR), and restriction fragment length polymorphism analysis of PCR products targeted the bacterial 16S rDNA. Rumen digesta and ruminally incubated hay stems had a reasonably high population size of F. succinogenes (×10^7?8/g) that was composed of strains belonging to the phylogenetic groups 1 and 3. The relative abundance of each group was different among the samples; group 1 dominated on the ruminally incubated hay stem and in the rumen of wethers fed fresh orchardgrass, while group 3 was major in the rumen of wethers and steers on hay diet. These results suggest that there could be phenotypic differences among the phylogenetic groups of F. succinogenes, and group 1 dominating on hay stem might contribute to rumen fiber digestion more than the other groups.