An Endophytic Actinomycete, Streptomyces sp. AOK-30, Isolated from Mountain Laurel and Its Antifungal Activity

To survey endophytic actinomycetes as potential biocontrol agents against fungal diseases of mountain laurel, young plants of mountain laurel (Kalmia latifolia L.) were used as an isolation source. From a total of 73 actinomycetes isolates obtained from leaves, stems and roots of test plants, Streptomyces sp. AOK-30 was selected, because i) it had a broad and intense antimicrobial spectrum against various yeasts and fungal pathogens of Ericaceae, ii) it grew on the multiplication and rooting media for tissue culture for this plant, and iii) the tissue-cultured seedlings that had been treated with this isolate became resistant to Pestalotia disease without any adverse growth effects such as malformation, dwarfing, discolorization and defoliation. This isolate was identified as Streptomyces sp., based on cultural, physiological and morphological characteristics. The present results indicate that isolate AOK-30 is a potential biocontrol agent against diseases of mountain laurel. Received 10 September 2002/ Accepted in revised form 22 November 2002     

Distribution of taste buds in layer‐type chickens: Scanning electron microscopic observations

The distribution of taste buds of layer‐type chickens, from day 1 (H1) to day 140 (H140) post‐hatching, were investigated histologically and with a scanning electron microscope. Two types of openings were observed on the oral epithelium: large openings that were greater than 10 μm in width, and had an ellipsoid or spindle shape; and small openings that were less than 7 μm in width, and had a circular or polygon shape. It was defined that the former represent the openings of the salivary glands, and the latter are those of the taste buds. The number of taste buds remained constant from H1 to H140. Therefore, no significant change was observed between these two time points. To investigate the distribution of the taste buds in the whole oral cavity, a distribution map was created.     

Bacteriocin production of probiotic Lactobacillus gasseri LA39 isolated from human feces in milk-based media

The use of bacteriocins from Lactobacillus gasseri , a probiotic lactic acid bacterium, as bio-preservatives in the food industry and animal formulations has been limited because few strains of Lb. gasseri are cultivated and produce a bacteriocin in natural media such as milk and milk-based media. By the determination of the growth-supplements to milk among the 47 nutrients, Lb. gasseri JCM1131^T, LA39 and LA158 isolated from human feces were successfully cultured in reconstituted skim milk and cheese whey using proteose peptone as a nutrient supplement, where Lb. gasseri LA39 produced a useful bacteriocin, gassericin A, with effective growth-inhibiting activity against Gram-positive food-borne pathogens. The data suggest these developed low-cost safe media supporting enough production of bacteriocins by the probiotic Lb. gasseri LA39 could be used to improve the safe bio-preservation of foods and therapy of bovine mastitis, and extra cheese whey produced by cheese making industry is reused in the cultivation for probiotics effectively.     

Effect of dietary Rhodobacter capsulatus on cholesterol, triglycerides concentration, and meat quality of finishing pigs

The study was designed to investigate the effect of Rhodobacter capsulatus on serum and meat cholesterol, fatty acid composition in meat, as well as meat quality of finishing pigs. A total of 16 120-day-old Landrace female pigs of about 60 kg initial body weight were randomly assigned into two groups. The pigs were fed a supplemented diet with 0.04% dietary R. capsulatus or a control diet for 60 days. Total cholesterol and low density lipoprotein-cholesterol concentration in serum was significantly lowered ( P  < 0.05) in the pigs fed the R. capsulatus supplemented diet compared to the control diet. Carcass weight, carcass length, shoulder fat, back fat and loin fat thickness, longissimus muscle (LM) area, and color score did not differ significantly between the pigs fed the R. capsulatus supplemented diet and control diet. Among the nutrient composition of LM meat, neutral fat and triglyceride concentration were significantly ( P  < 0.05) reduced in the finishing pigs by dietary supplementation of R. capsulatus . The proportions of n-6 PUFA were higher ( P  < 0.05) in the pigs fed the R. capsulatus supplemented diet than in the pigs fed the control diet. The supplementation of dietary R. capsulatus to finishing pig diet played important roles in reducing serum cholesterol and meat triglycerides, as well as in increasing polyunsaturated fatty acid content in LM meat.     

Comparative observation on the growth changes of the histochemical properties and collagen architecture of the Musculus puboischiofemoralis pars medialis from Silky, layer-type and meat-type cockerels

Growth‐related changes in the histochemical properties and collagen architecture of the Musculus puboischiofemoralis pars medialis were compared among Silky, layer‐type, and meat‐type cockerels. Histochemical and immunohistochemical methods were employed and collagen architecture was studied using scanning electron microscopy. Total intramuscular collagen was also determined. The myofibers were categorized as type I, type IIA and a transitional form, type I‐tr. The proportion of type I‐tr myofibers diminished and these myofibers were transformed entirely into type I myofibers in meat‐type but incompletely in the others. The largest diameter of type I myofiber was found in layer‐type at 30 weeks of age. At 30 weeks of age, layer‐type birds had attained well‐developed perimysial collagen bundles while meat‐type birds had less developed bundles. The endomysial collagen network had a large mesh size at 1 week and then accumulated many collagen fibrils to form a felt‐like fabric of fibrils by 30 weeks of age. Silky birds developed the thickest endomysial collagen plates of all the breeds. From these results it appears that growth‐related changes in the histological structure of M. puboischiofemoralis pars medialis are not necessarily causally affected by the different growth rates of chicken breeds.     

Lymphangiosarcoma with systemic metastases in a Japanese domestic cat

A 4-year-2-month-old female Japanese domestic cat was diagnosed with lymphangiosarcoma through tissue biopsy of an amputated leg. Two months later, the cat was euthanized, and postmortem findings revealed edema, and bruising at the caudal region of the trunk, pulmonary hemorrhage, pulmonary nodules and mediastinal lymphadenopathy. Microscopically, neoplastic tissues were observed in the dermis and subcutis of the trunk, lung, mediastinal lymph nodes, diaphragm, omentum and mesentery. The tumor cells were spindle to polygonal-shaped with nuclear pleomorphism aligning along pre-existing collagen bundles and forming irregular vascular channels in which the erythrocytes were rarely observed. These cells were immunopositive for vimentin, von Willebrand factor and CD31. Based on the histopathological and immunohistochemical features, the neoplasia was diagnosed as lymphangiosarcoma with systemic metastases.     

Characterization of triple-phase computed tomography in dogs with pancreatic insulinoma

Little information is available regarding triple-phase computed tomography (CT) of canine pancreatic insulinoma. A few case reports with small numbers of cases have indicated that hyper-attenuation in the arterial phase was a common finding on multi-phasic CT in dogs with insulinoma. Our purpose was to clarify the characteristic findings of dogs with insulinoma on triple-phase CT. Nine dogs with insulinoma that underwent triple-phase CT were included in the present study. Attenuation patterns in the arterial phase indicated hypo-attenuation in 4 cases and hyper-attenuation in 2 cases. In the remaining 3 cases, 1 case showed hypo-attenuation and 1 case showed hyper-attenuation in the pancreatic phase, and 1 case presented hyper-attenuation in the later phase. Altogether, 5 cases showed hypo and 4 cases showed hyper-attenuation in at least one phase. The enhancement pattern was homogenous in 7 cases and heterogeneous in 2 cases. Tumor margins were well-defined in 5 cases and ill-defined in 4 cases. Capsule formation was present in 5 cases and absent in 4 cases. In conclusion, it is important to note that hypo-attenuation was as common as hyper-attenuation in dogs with insulinoma in triple-phase CT in at least one phase. Additionally, mass lesions were most conspicuous not only in the arterial phase but in the pancreatic and later phases in some cases. Therefore, it is important to perform triple-phase CT and notice about variable findings for the detection of canine pancreatic insulinoma.     

Oral ingestion of collagen peptide causes change in width of the perimysium of the chicken iliotibialis lateralis muscle

Skeletal muscle is mainly composed of myofibers and intramuscular connective tissue. Bundles composed of many myofibers, with each myofiber sheathed in connective tissue called the endomysium, are packed in the perimysium, which occupies the vast bulk of the intramuscular connective tissue. The perimysium is a major determination factor for muscle texture. Some studies have reported that collagen peptide (Col-Pep) ingestion improves the connective tissue architecture, such as the tendon and dermis. The present study evaluated the effects of Col-Pep ingestion on the chicken iliotibialis lateralis (ITL) muscle. Chicks were allocated to three groups: the 0.15% or 0.3% Col-Pep groups and a control group. Col-Pep was administered by mixing in with commercial food. On day 49, the ITL muscles were analyzed by morphological observation and the textural property test. The width of the perimysium in the 0.3% Col-Pep group was significantly larger than other two groups. Although scanning electron microscopic observations did not reveal any differences in the architecture of the endomysium, elastic improvement of the ITL muscle was observed as suggested by an increase of the width of perimysium and improved rheological properties. Our results indicate that ingestion of Col-Pep improves the textural property of ITL muscle of chickens by changing structure of the perimysium.     

The Usefulness of Captive Kept Capercaillie (Tetrao urogallus L.) as the Semen Donors for Artificial Insemination and Gene Pool Preservation In vitro

Captive breeding of birds threatened by extinction in zoological gardens or other closed aviary centres is one of the methods allowing their protection and gene pool preservation ex situ in vivo. Such birds are usually kept in captivity lifelong and serve as parents of several new generations that can be further released into natural environment, or males are used as semen donors for artificial insemination and gene banking. Therefore, the fecundity of such flocks (number of laid egg and spermatozoa quantity and quality) is very important. The aim of this study was to evaluate the usefulness of captive kept capercaillie (Tetrao urogallus L.) as semen donors in three subsequent reproductive seasons, based on the assessment of manually collected semen quality. Male response to dorso‐abdominal massage, ejaculate volume, sperm concentration, motility and morphology were evaluated individually at three succeeding years. Depending on individual male properties and year of collection, the number of positive reactions to semen collection attempts (i.e. ending with ejaculation) varied from 44.4% to 100.0%; single ejaculate volume ranged from 10 to 300 μl, spermatozoa concentration from 10 × 10⁶ per ml to 3520 × 10⁶ per ml and percentage of live morphologically normal spermatozoa from 19.3 to 80.3%. The highest average value (66.7) of semen quality factor (SQF) was noted for a 2‐year‐old male (varying from 1.9 to 258.1), while the lowest for ten‐ (4.8; varying from 0.1 to 17.0) and 7‐year‐old (6.6; varying between 0.6 and 13.6). Assuming that for AI purposes, the ejaculate quality has to be at minimum 10 SQF, obtained results indicate that majority of capercaillie kept in captivity, both young (2–3 years old) and older (up to 10 years old), can be valuable semen producers in succeeding seasons.     

In vitro measurement of post‐natal changes in proliferating satellite cell frequency during rat muscle growth

Satellite cells, resident myogenic stem cells found in postnatal skeletal muscle, are most abundant during early postnatal development and sharply decline in frequency thereafter to adult levels in mice and rats. Therefore, postnatal changes in satellite cell mitotic activities are important aspects for further understanding a muscle growth strategy. In large meat‐production animals, however, the traditional in vivo proliferation assay may be less realistic because it requires intra‐peritoneal (ip) injection of huge dosage of mutagenic nucleosides, ³H‐labeled thymidine or bromodeoxyuridine (BrdU), at each age‐time of sacrifice. We report in the present pilot study using rats that in vivo proliferation activity of satellite cells can be evaluated by an in vitro BrdU‐incorporation assay in early cultures. Briefly, satellite cells were prepared from upper hind‐limb and back muscles and maintained for 24 h with imposing by BrdU addition for the last 2 h, followed by the regular immunocytochemistry for determining BrdU‐incorporated cell percentage. This in vitro assay demonstrated a rapid decrease in proliferating satellite cell frequency to the adult level during about 3‐month period after birth, and yielded a high correlation to the measurements by the in vivo BrdU ip‐injection method during the postnatal period examined from day‐2 to month‐11. The in vitro proliferation assay may be further adaptable for large domestic animals by the combination with a muscle biopsy technique that enables age‐interval sampling from the same growing animals.