Effects of an 'enrichment feeder' on behavior and feather conditions of caged laying hens

The objective of this study was to compare the behaviors and feather conditions of caged laying hens fed by two different types of feeders. Seven tennis balls were placed on the feed trough to hide the feed for each of 6 experimental cages (treatment B). The same feed troughs without balls were used for 6 control cages (treatment NB). Forty-eight commercial white leghorn type hens were housed as 4 birds per cage (474 cm² per bird). The experimental period was from 22 to 32 weeks of age. At 28 weeks of age, the hens spent more time feeding in treatment NB (35%) than in B (27%). On the other hand, prefeeding behavior (extension of the neck over the trough or pecking at the balls) occupied more time in B (14%) than in NB (6%). The birds in B spent more time thrusting (thrusting other birds aside and trying to eat) than did the birds in NB (2 vs 0%). At 32 weeks of age, the mean proportion of hens feeding and prefeeding behavior in both treatments was similar to those at 28 weeks of age; however, differences of the behavior between the B and NB were relatively small. Feather damage on a scale of 0 (no damage) to 15 (denuded) increased with age, and the scores in B were less than those in NB at 27 weeks (0.75 vs 1.37), although not at 32 weeks. Egg production in the two treatments was the same, and the type of feeder used did not affect body weight. This device might provide hens with a more attractive environment than the conventional feeders; however, the enrichment feeder might need more improvement for the welfare of caged laying hens.     

Season- and Age-related Reproductive Changes Based on Fecal Androgen Concentrations in Male Koalas,Phascolarctos cinereus

The purposes of the present study were to clarify age- and season- related androgen patterns, and to compare the reproductive physiology between Japanese captive koala populations and Australian populations. To measure fecal androgens, feces were collected from male koalas (4.2 to 13.8 years of age) kept in Japanese zoos. Fecal androgens were extracted with methanol from the lyophilized samples and determined by enzyme immunoassay using 4-androstene-3,17-dione antibody. Fecal androgen concentration in male koalas increased after sexual maturation and remained relatively high until old age. In the survey with the Japanese zoo studbook of koalas, copulation (conception) month showed a pyramid shape with a peak in March to June (60.7%) in koalas born and reared in Japanese zoos and from July to April with the highest concentration in September to January (69.7%) in Australian institutes. Japanese zoo koala populations have a characteristic physiological cycle adapted to Japan''s seasonal changes. The suitable month of year for copulation or conception in Japan is diametrically opposed to that in Australia. Mean fecal androgen concentrations by month in the males born and reared in Japan indicated annual changes with the highest concentration in May and the lowest value in November. Fecal androgen analysis may be a noninvasive alternative tool to monitor circulating testosterone and may be helpful in understanding reproductive activity and physiology in male koalas.     

Detection of squamous cell carcinoma of presumed pancreatic origin and its metastasis in a spotted seal (Phoca largha) using ultrasonography and computed tomography

A 21-year-old female spotted seal (Phoca largha), with a swollen abdomen, had a five-month history of anorexia and vomiting. Ultrasonography revealed an extended mass with central necrotic foci in the right cranial abdomen. Computed tomography revealed an abdominal mass with a low-density central lumen and a pulmonary nodular lesion. Cytology of an abdominal specimen collected through fine-needle aspiration indicated a malignant tumor with round, atypical cells with large nuclei. Three days after diagnosis, necropsy revealed a 10-cm large, solid, whitish mass in the pancreatic parenchyma and multiple small nodules in the liver, spleen, mesentery, lungs, and mediastinal lymph nodes. Histopathological analysis showed prolific neoplastic cells with marked atypia and occasional keratinization. Immunohistochemistry revealed that the neoplastic cells were positive for cytokeratin AE1/AE3 antibody. Thus, the seal was diagnosed with squamous cell carcinoma, of presumed pancreatic origin, which had metastasized to multiple organs.     

Morphological Studies on Zoospores of Aphanomyces cochlioides and Changes during Interaction with Host Materials

The behavioral and morphological diversity of intact zoospores of Aphanomyces cochlioides and their dynamic morphological changes when interacting with the host or a host-specific zoospore attractant were studied by light and electron microscopy. The reniform-ovate zoospore has two heterokont flagella, both inserted in a ventral groove. The anterior flagellum possesses two rows of tripartite tubular hairs (TTHs) distributed throughout its length, whereas the posterior flagellum was ornamented with two rows of highly dense fine tubular hairs, except on its tapered terminal part. The tip of the posterior flagellum has a bunch of similar fine hairs like those on the flagellum shaft. The biflagellated zoospores quickly aggregated on the host (spinach) root, adhered to the root surface, encysted by shedding or retracting the flagella, germinated at a fixed point to form germ tubes, and finally invaded the root tissues via the appressoria within 50–60 min. This precise homing response of A. cochlioides zoospores reflects guidance by a host-specific signal(s) for locating potential infection sites, differentiation of zoospores to cystospores, formation of infection structures and/or germ-tube tropism for completing pre-infection events in haste. Prior to the encystment, the posterior flagellum may be involved in successful docking on the root surface by tip contact followed by shedding or retraction. Received 22 January 2001/ Accepted in revised form 28 May 2001     

A possible function of Nik-related kinase in the labyrinth layer of delayed delivery mouse placentas

In mice and humans, Nik-related protein kinase (Nrk) is an X-linked gene that encodes a serine/threonine kinase belonging to GCK group 4. Nrk knockout (Nrk KO) mice exhibit delayed delivery, possibly due to defective communication between the Nrk KO conceptus and its mother. However, the mechanism of delayed labor remains largely unknown. Here, we found that in pregnant mothers with the Nrk KO conceptus, the serum progesterone (P4) and placental lactogen (PL-2) concentrations in late pregnancy were higher than those in the wild type. Moreover, we demonstrated that Nrk is expressed in trophoblast giant cells (TGCs) and syncytiotrophoblast-2 (SynT-2) in the labyrinth layer of the mouse placenta. In the human placenta, NRK is also expressed in Syn-T in villi. Both human Syn-T and mouse TGCs of the labyrinth layer are present within fetal tissues that are in direct contact with the maternal blood. The labyrinth layer of the Nrk KO conceptus was gigantic, with enlarged cytoplasm and Golgi bodies in the TGCs. To investigate the function of Nrk in the labyrinth layer, a differentially expressed gene (DEG) analysis was performed. The DEG analysis revealed that labor-promoting factors, such as prostaglandins, were decreased, and pregnancy-maintaining factors, such as the prolactin family and P4 receptor, were increased. These findings suggest that the Nrk KO mice exhibit delayed delivery owing to high P4 concentrations caused by the hypersecretion of pregnancy-maintaining factors, such as PL-2, from the placenta.     

Isolation of antifungal-resistant yeasts from bulk milk in Japan

We isolated ascomycetous yeasts including Candida species, that originally belonged to the genus Candida, from bulk milk in the Aichi area of Japan, and determined the minimum inhibitory concentrations (MICs) of antifungal drugs on these isolates by conducting E-tests. We isolated 7 human pathogenic species (14 isolates) from 14 bulk milk samples: 5 Candida species of yeasts, and 2 Candida-related species. Two isolates of C. albicans and C. inconspicua were resistant to fluconazole (MIC >32 mg/l). One isolate of C. krusei was resistant to both azoles (fluconazole: >256 mg/ml and itraconazole: 4 mg/l). One isolate of C. catenulata might be resistant to amphotericin B (>32 mg/l).     

An insertion/deletion variant of a thymine base in exon 2 of the porcine beta 3‐adrenergic receptor gene associated with loin eye muscle area

An insertion/deletion variant of a thymine base (T5 and T6) in exon 2 of porcine beta 3‐adrenergic receptor (ADRB3) gene has been described. In the current study, we made an association study between the ADRB3 polymorphisms and production traits in 735 Duroc pigs. The allele frequencies for the T5 and T6 alleles in our study population were 0.433 and 0.567, respectively. Any associations between ADRB3 genotype and average daily weight gain during test period, or backfat thickness and intramuscular fat content were not detected in either sex. However the size of the loin eye muscle area (EMA) was significantly associated with ADRB3 genotypes in gilts. T6‐homozygous gilts had a higher mean of EMA (40.6 ± 0.6 cm²) than T5‐homozygous (38.1 ± 0.4 cm², P = 0.002) and heterozygous (38.8 ± 0.3 cm², P = 0.034) gilts. This association was not detected in males. In addition, a multiple traits animal model best linear unbiased predictor (BLUP) analysis revealed that the T6‐homozygous genotype had positive effects on breeding value of EMA. Accordingly, we suggest that ADRB3 polymorphism has the potential to be an important genetic marker for prediction of EMA in Duroc pigs.