Lymphography of the thoracic duct by percutaneous injection of iohexol into the popliteal lymph node of dogs: experimental study and clinical application

OBJECTIVE: To evaluate the efficacy of percutaneous administration of iohexol into the popliteal lymph node as a non-invasive technique for thoracic duct lymphangiography in dogs. STUDY DESIGN: Experimental study and clinical report. ANIMALS: Normal adult dogs (n=4) and 1 dog with recurrent chylothorax. METHODS: For the experimental study, 4 dogs (weight, 8.4-12.3 kg) had 5-10 mL iohexol injected percutaneously into 1 popliteal lymph node and then thoracic radiographs were taken. Popliteal lymph nodes were examined by histopathology 8 days later. One 25-kg dog with recurrent chylothorax had 25 mL iohexol injected into the right popliteal lymph node followed by thoracic radiography. RESULTS: In experimental dogs, the thoracic duct was best visualized on thoracic radiographs after administration of 10 mL iohexol. Clinically, no abnormalities were identified in the injected limb and except for 1 dog that had large numbers of siderocytes and erythrophagocytic macrophages in the injected lymph node, the histopathologic findings in the other injected popliteal lymph nodes were not different from contralateral nodes. In the clinical case, the thoracic duct was visualized, but there was leakage of iohexol around the node. CONCLUSION: The thoracic duct in dogs can be visualized by lymphography after percutaneous injection of iohexol (1 mL/kg at 2 mL/min) into the popliteal lymph node. CLINICAL RELEVANCE: Percutaneous popliteal lymph node administration of iohexol should be considered as an alternative to mesenteric lymph node injection for radiographic identification of the thoracic duct in dogs.     

Behavioral changes in laying hens after introduction to battery cages, furnished cages and an aviary

A variety of investigations into alternative systems and furnished cages for laying hens have been conducted, mainly in the European Union. However, comparative studies about the behavior of laying hens just after introduction to these housing systems are few. Therefore, this study aimed to investigate the changes of location and behavior of laying hens just after introduction to three housing systems. In total, 181 White Leghorns were used. Thirty‐six birds were allocated to 12 battery cages with three birds per cage (613 cm²/bird); 36 birds were allocated to nine furnished cages with four birds per cage (1170 cm²/bird); and 109 birds were allocated to an aviary (1130 cm²/bird). Direct observations using scanning techniques were conducted over 2 weeks for 4 h/day from the day following the introduction. Scan samples of location and behavior were taken at 10 min intervals. The proportion of birds that stayed at each location in the furnished cages was stable during the observation period. In the aviary, 78% of birds were observed on the floor on the first day, and thereafter the proportion linearly decreased (P < 0.01). The proportions of birds eating in both the battery and furnished cages were stable, indicating that the caged birds would adjust to these environments within a short period. Display of aggression was lower in both the cages (both 0.3 ± 0.1%) than in the aviary (3.5 ± 1.0%, P < 0.001), which indicates the early establishment of social order in both cage systems. In the aviary, the birds were observed eating less frequently than in both the cages on the first day, and the proportion thereafter linearly increased (P < 0.01), and the use of tiered wire floors with feeders accompanied this (P < 0.01). Comfort behaviors, including dust bathing, were noted less in the aviary than in the furnished cages throughout the observation period (both P < 0.05). These results suggest that adjustment of aviary birds to their new environment had been delayed compared with caged birds because of the prerearing conditions and the environmental complexity of the aviary.     

Hormonal and metabolic relation to restraint and human handling in growing-fattening steer

Endogenous relationship to restraint and human handling were studied with growing–fattening steers. Thirty‐five crossbred (Japanese Black × Holstein) steers aged 6–10 months were randomly assigned to three pens. They had free access to an Italian ryegrass hay and a restricted amount of high‐concentrate diets (total digestible nutrients (TDN) 70.5%, digestible crude protein (DCP) 10.0%) for the first 6 months of trial. Then they had free access to an oat hay and another vitamin A‐restricted diet (TDN 72.0%, DCP 10.0%) until slaughter. The steers were individually driven into a restraint stall, and bodyweight was recorded. Blood samples were then collected under haltered conditions. These serial handling procedures started at 2 h after the morning feeding were conducted in months 1, 3, 5 (growing stage, GS) and in months 7, 9, 11 (fattening stage, FS) of the trial. Mean peripheral blood concentrations of epinephrine (A; GS, 117.4 ± 76.4 pg/mL; FS, 64.1 ± 34.2 pg/mL), norepinephrine (NA; GS, 257.7 ± 95.0 pg/mL; FS, 125.9 ± 44.1 pg/mL), cortisol (GS, 1.6 ± 0.8 µg/dL; FS, 1.2 ± 0.4 µg/dL), glucose (GS, 83.1 ± 7.5 mg/dL; FS, 71.9 ± 6.9 mg/dL), non‐esterified fatty acid (NEFA; GS, 0.13 ± 0.06 mEQ/L; FS, 0.10 ± 0.06 mEQ/L) and vitamin A (GS, 90.5 ± 24.6 IU/dL; FS, 37.2 ± 21.3 IU/dL) were higher (all P < 0.01) in the GS than in the FS, whereas those of insulin (GS, 1.06 ± 0.82 µU/mL; FS, 1.36 ± 0.61 µU/mL) and leptin (GS, 4.5 ± 1.8 ng/mL human equivalent (HE); FS, 6.8 ± 2.4 ng/mL HE) were lower (both P < 0.01). The metabolite that correlated with A and NA was glucose (A: r = 0.61, P < 0.001; NA: r = 0.53, P < 0.01) in the GS, and the metabolites correlating with A, NA and cortisol were NEFA (A: r = 0.31, P < 0.10; NA: r = 0.32, P < 0.10; cortisol: r = 0.41, P < 0.05) and triglyceride (A: r = ?0.37, P < 0.05; NA: r = ?0.39, P < 0.05) in the FS. Vitamin A was a mediator between A (r = ?0.38, P < 0.05) and NA (r = ?0.42, P < 0.05) and insulin (r = 0.31, P < 0.10) in the GS, and between NA (r = ?0.33, P < 0.10) and leptin (r = 0.38, P < 0.05) in the FS. In conclusion, when changing from the growing to the fattening stages, the stress of handling and restraint had caused the pathways to shift from carbohydrate metabolism to lipid metabolism. In addition, vitamin A seemed to be an important mediator in the endogenous pathways in both stages.     

Choice of attractive conditions by beef cattle in a Y-maze just after release from restraint: Effect of sheep

To provide useful information on how to moderate post‐handling stress, Angus heifers (n = 157) were individually allowed to enter a choice area after 2 min of restraint in a crush and to choose between two pens. After the animal had chosen a pen, free access was given to both test pens and the choice area for a further 5 min. The behaviors during choice and after the first choosing were observed. In experiment 1, each heifer was given one of the following choices: pen with three familiar heifers (peers) versus pen with six sheep (sheep; n = 30); peers versus the bare pen (bare; n = 30); sheep versus bare (n = 30). When the choice combination was peers versus bare, more heifers than expected by chance chose the peers pen (χ² = 4.80; P < 0.05). However, when one of the other choice combinations was given, there was no significant difference between the number choosing a pen and the expected value. After the first choice, more heifers entered the peers pen than the bare pen (P < 0.05) or the sheep pen (P < 0.10). In experiment 2, another 67 heifers were given one of the following choices: peers versus pen with a novel object (NO; n = 19); sheep versus NO (n = 22); bare versus NO (n = 26). There was no significant difference between the number of heifers choosing a pen and the expected value in any choice combination. However, more heifers entered the peers pen than the NO pen (P < 0.01). It is concluded that sheep were not as attractive as peers, but sheep were not fearful animals for cattle.     

Production of mouse fibroblast growth factor 4 in E. coli and its application for isolation and maintenance of mouse trophoblast stem cells in vitro

Fibroblast growth factor 4 (FGF4) promotes isolation of trophoblast stem (TS) cells from mouse blastocysts and maintenance of TS cells in an undifferentiated state in vitro. To date, commercially available, bacterially expressed human FGF4 (RhFGF4) has been used generally for this purpose. In this study, HismFGF4, a 6x histidine-tagged mouse FGF4, was produced in E. coli and purified using heparin column chromatography. We demonstrated that HismFGF4 (25 ng/ml) more efficiently generates mouse TS cells from a single blastocyst than RhFGF4 (25 ng/ml) and that TS cells isolated and maintained with HismFGF4 retained their ability to differentiate into the trophoblast cell lineage in vitro. In addition, TS cells cultured with HismFGF4 (25 ng/ml) were maintained in an undifferentiated state better than with RhFGF4 (25 ng/ml). To the best of our knowledge, this is the first application of a mouse FGF4 derivative for isolation and maintenance of mouse TS cells.     

Autologous tunica vaginalis communis flap for repairing an abdominal wall hernia in a dog

An 8-year-old, intact male miniature dachshund dog, weighing 8.6 kg, was presented with a soft swelling in the caudal abdominal region, including both sides of the groin area. Laparotomy revealed a severe caudal abdominal wall hernia with atrophy of the rectus abdominal muscle. The defect was repaired using a tunica vaginalis communis flap following a standard open prescrotal castration. There were no complications or recurrence of the hernia at 11 months after surgery. This surgical technique involves autogenous reconstruction, is easy to perform, and requires minimal dissection. The tunica vaginalis communis flap has potential clinical applications for repairing caudal abdominal wall hernias in male dogs.     

Retort beef aroma that gives preferable properties to canned beef products and its aroma components

The objective of this study is to identify the properties and responsible compounds for the aromatic roast odor (retort beef aroma) that commonly occurs in canned beef products and could contribute to their palatability. The optimal temperature for generating retort beef aroma was 121°C. An untrained panel evaluated both uncured corned beef and canned yamato‐ni beef and found that they had an aroma that was significantly (P < 0.01) similar to the odor of 121°C‐heated beef than 100°C‐heated beef. The panel also noted that the aroma of 121°C‐heated beef tended to be (P < 0.1) preferable than that of 100°C‐heated beef. These results suggest that retort beef aroma is one constituent of palatability in canned beef. GC‐MS (gas chromatography‐mass spectrometry) analysis of the volatile fraction obtained from 100°C‐ and 121°C‐heated beef showed that the amounts of pyrazine, 2‐methylpyrazine and diacetyl were higher in the 121°C‐heated beef than in the 100°C‐heated beef. GC‐sniffing revealed that the odor quality of pyrazines was similar to that of retort beef aroma. Therefore, pyrazines were suggested to be a candidate responsible for the retort beef aroma. Analysis of commercial uncured corned beef and cured corned beef confirmed the presence of pyrazine, 2‐methylpyrazine and 2,6‐dimethylpyrazine.     

Effects of light intensity and beak trimming on preventing aggression in laying hens

This study aimed to investigate the effects of decreased light intensity and beak trimming on aggression prevention in laying hens. In total, 181 White Leghorns were used. At 17 weeks of age, 36 birds were allocated to battery cages (three birds/cage), 36 birds to furnished cages (four birds/cage), and 109 birds were transferred to an aviary. Since aggression increased in the birds from 23 weeks of age (from 0.3% to 6.0%) especially in the furnished cages, , the light intensity during the daytime was decreased to about one‐tenth (from 680 lux to 70 lux) at 28 weeks of age. The birds in the furnished cages then had their beaks re‐trimmed lightly by using a debeaker at 29 weeks of age. Behavioral observations using scanning techniques at 10 min intervals were conducted. Feed intake, bodyweight and feather score were also measured. There was no significant difference in aggression before and after decreasing the light in all three housing systems. On the other hand, the proportion of birds showing aggression decreased significantly just after trimming and four weeks after beak trimming in the furnished cages (P < 0.05 and P < 0.01, respectively). The aggression also became similar to the proportions observed in the battery cages and in the aviary. In proportion to the decreased aggression, the proportion of birds eating significantly decreased (P < 0.05). However, their feed intake and bodyweight did not decrease significantly. Against this decreased aggression, the proportion of birds preening significantly increased (P < 0.05). Aggression was observed more frequently at the dust bath in the furnished cages and at the litter floor in the aviary (both P < 0.001). The total feather score for all body parts in the birds in furnished cages increased significantly (P < 0.01) from 25 to 29 weeks of age (at beak trimming), but did not increase significantly from 29 to 33 weeks of age. The increments of neck, breast and tail feather scores in the furnished cages were smaller. In conclusion, there was no significant difference in aggression between just before and after decreasing the light in any housing system. However, aggression in the furnished cages was reduced not only by decreasing the light intensity, but by additional beak trimming. Aggravation of feather conditions – especially at the neck, breast and back – was prevented by the treatment.     

Adventitious root formation of two <Emphasis Type="Italic">Abies</Emphasis> species on log and soil in an old-growth subalpine forest in central Japan

We assessed stem burial and adventitious root formation of two late-successional species, Abies mariesii and A. veitchii, in central Japan. In a plot (5 × 5 m), all seedlings between 8 and 24 cm tall were excavated: six A. mariesii seedlings in soil, and six and four A. veitchii seedlings in soil and on logs, respectively. For each sampled seedling, the number of terminal bud scars (TBS) was counted on the aboveground and belowground stems. Stem length was measured, and divided into aboveground and belowground stems. Among the three groups (A. mariesii seedlings in soil and A. veitchii seedlings in soil or on logs), there was no significant difference in height or total root weight (sum of adventitious roots and primary roots), but diameter at ground level and number of TBS were significantly different. Counting TBS on the aboveground stem of seedlings in soil underestimated seedling age, whereas the estimate was much closer to the true age for seedlings on logs. Seedlings in soil formed more adventitious roots than seedlings on logs. A large proportion of the stem was buried in humus for seedlings in soil, while most of the stem was not buried in humus for seedlings on logs. These results suggest that substrate affects adventitious root formation, the formation of which is important to shade tolerance. Thus, our preliminary results suggest that consideration of adventitious root formation is necessary to understand seedling bank dynamics and estimate seedling ages of these Abies species in spatially heterogeneous old-growth subalpine forests.