Three-dimensional reconstruction of intramuscular collagen networks of bovine muscle: A demonstration by an immunohistochemical/confocal laser-scanning microscopic method

We undertook a three‐dimensional reconstruction of intramuscular collagen networks of bovine muscle using an immunohistochemical/confocal laser‐scanning microscopic method. By immunohistochemical staining, type I and III collagens were observed mainly in the perimysium, while type IV collagen was observed in the endomysium. On the other hand, type V and VI collagens were observed in both the perimysium and endomysium. By confocal laser‐scanning microscopy, the collagen observed in the perimysium was three‐dimensionally reconstructed as plate‐shaped layers whereas the collagen observed in the endomysium surrounded myofibers. The three‐dimensionally reconstructed observations using immunohistochemical/confocal laser‐scanning microscopic method is useful for investigating collagen networks in muscle.     

Feed intake, lactation performance, blood metabolites and fertility in early lactation dairy cows grazing a timothy pasture

The present study was conducted to investigate feed intake, milk yield, milk composition, blood metabolites and fertility in early lactation dairy cows grazing a timothy pasture. Fourteen multiparous Holstein cows that calved between 20 May and 19 July were used over a 3‐year period. The stocking rate was 3.6–4.3 cow/ha. Concentrates were fed separately at 9.5–11.5 kg/day per cow (dry matter basis) from 1 to 13 weeks postparturition. Herbage intake was estimated using chromium oxide as an indigestible marker. The mean contents of crude protein, total digestible nutrients and neutral detergent fiber of pasture during the 3‐year study period were 22.3%, 71.8% and 51.7%, and those of total diet were 18.9%, 77.3% and 40.3%, respectively. The mean herbage dry matter intake was 13.0 kg/day from 2 to 13 weeks postparturition during the study, total dry matter intake was 23.7 kg/day, the total digestible nutrients sufficiency rate was 105%, milk yield was 39.7 kg/day, and milk fat percentage was 3.30%. The decrease in bodyweight postparturition was slight. Urea nitrogen concentrations in serum were below 18.3 mg/dL. The mean days to first estrus and days open were 36 and 104 days, respectively. These results indicate that energy deficiency, decrease in bodyweight and fertility in early lactation barely occur when high producing dairy cows are fed enough grazing grass and suitable concentrates.     

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     

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.     

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.     

Detection of indoleamine 2,3-dioxygenase 1-expressing cells in canine normal and tumor tissues

Cancer immunotherapy is a novel cancer treatment for canine tumors. Indoleamine 2,3-dioxygenase 1 (IDO1) is overexpressed in some human tumors and inhibits antitumor immunity. In this study, we comprehensively evaluated expression pattern of IDO1 and the nature of IDO1-expressing cells in canine normal and tumor tissues. In normal tissue samples, IDO1 expression was detected only in the lymph nodes, spleen, tonsil tissues, and colon tissues. In contrast, IDO1-positive tumor cells were observed in several tumor tissue types. This is the first study to evaluate IDO1 expression in canine normal and tumor tissues, and the results suggest that IDO1 is a promising target for novel cancer immunotherapy in dogs with tumors.     

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.     

Behavior of simetryn and thiobencarb in rice paddy lysimeters and the effect of excess water storage depth in controlling herbicide run‐off

Eight small‐scale lysimeters with different excess water storage depths (EWSDs) were used to investigate the behavior of two herbicides, simetryn and thiobencarb, under paddy conditions. The concentration of simetryn dissipated similarly in all the lysimeters, while the thiobencarb concentration varied significantly because thiobencarb can adsorb onto the dissolved organic matter in a manure slurry, which was applied to six of the lysimeters. The herbicide losses (the percentage of the applied mass) from the lysimeters were reversely proportional with the EWSD. The correlation was stronger for simetryn than for thiobencarb. An appropriate EWSD is required to effectively prevent herbicide run‐off from the paddy field, especially when a rainfall event occurs soon after herbicide application.