Identification and characterization of proteoglycans in bovine neonatal skeletal muscle

In order to provide background for understanding biological roles of proteoglycans (PG) in developing skeletal muscle, we have isolated and characterized PG in bovine neonatal skeletal muscle. Two types of PG were isolated from skeletal muscle by density gradient ultracentrifugation and ion‐exchange chromatography. One was a small PG (PG‐S) with a molecular size of 100–130 kDa, another was a large PG (PG‐L) with a molecular size of 300–500 kDa. The glycosaminoglycan chains of PG‐S and PG‐L were dermatan sulfate and chondroitin sulfate, respectively, judged by cellulose acetate membrane electrophoresis. Immunoblot assays revealed that both PG bound to type I, II, III and IV collagen, laminin and fibronectin. Unlike PG‐S, PG‐L bound to type V collagen and hyaluronic acid. Small proteoglycans had a core protein of 45 kDa, which reacted with the antibody against the decorin core protein. The N‐terminal amino acid sequence of the PG‐S core protein was consistent with that of decorin from bovine bone and tendon. Thus, PG‐S from neonatal skeletal muscle was identified as decorin in bovines. Immunohistochemical analysis with antibodies against PG‐L and PG‐S demonstrated that PG‐L was located both in the perimysium and endomysium, but PG‐S was localized exclusively in the perimysium. These findings suggest that the characterized PG may have distinct roles in the ECM construction of developing skeletal muscle.     

Changes of histochemical profiles of myofibers in pectoralis and supracoracoideus fasciculi induced by breeding for large or small body size in Japanese quails

The histochemical profiles of myofibers in Musculus pectoralis (PT) and M. supracoracoideus (SC) fasciculi were compared among Japanese quail strains with large, normal and small body sizes. In male and female adults, both the PT and SC muscles had attained a 2.5–2.7-fold weight gain in the large strain and conversely a 0.43–0.50-fold change in the small strain relative to those of the normal size. The muscles were composed of fasciculi with a central cluster of type IIA fibers surrounded by a peripheral layer of type IIB fibers. In the large strain, the cross sectional area (CSA) of the fasciculus and CSA of the fibers in each type were significantly enlarged compared with those in the normal size, with the exception of the fasciculus in the deep region of the male PT muscle. The hypertrophied type IIA fibers in the large strain showed considerable variation in nicotinamide adenine dinucleotide dehydrogenase activity, some of which might represent a transitional form into type IIB fibers. In the small strain, the fasciculus CSA did not significantly differ from that of the normal size except for the PT surface region of the male. However, fiber atrophy was observed in type IIB fibers of the PT surface region in both sexes, and type IIA fibers of the PT deep region and SC muscle in the small strain male quails. The relative fiber type composition of a fasciculus in each region showed only a slight change across the strains. These results indicate that breast muscle hypertrophy in the large strain could be based mainly on fasciculus and fiber hypertrophy, but muscle atrophy in the small strain is not induced by fasciculus and fiber atrophy.     

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.     

Effects of an environmental enrichment using a drum can on behavioral, physiological and productive characteristics in fattening beef cattle

To evaluate the effects of environmental enrichment on behavioral, physiological and productive characteristics, 71 Japanese Black × Holstein steers (8 months of age; 299.5 ± 22.6 kg) were allocated to three pens in two repetitive experiments. Pen C (n = 11 and 12) consisted of a feeding alley for grain feed, a trough for dry hay, a water bowl and a resting space as a control pen. Pen D (n = 12 and 12) included a drum can (58 cm diameter × 90 cm height) containing hay. Pen GD (n = 12 and 12) included a drum can that was placed around artificial plastic turf (30 × 120 cm) for grooming. The drum cans were removed after 5 months of installation. Behavioral observations were made for 2 h at 10 min intervals after feeding on three successive days each month for 10 months. Agonistic interactions were also continuously observed for 1 h after feeding to assess the dominance order (DO). Sampling blood and measuring bodyweight were performed bimonthly. The steers used the drum can frequently for 3 months after installation (1st, 2nd, 3rd months vs 4 months, all P < 0.05). The frequency of total eating of grain feed and hay was higher in pen D and pen GD than in pen C (both P < 0.01), while it was lowest in pen GD after removal of the drum can (P < 0.05). Grooming at the drum can was observed more frequently in pen GD than in pen D (P < 0.05). After they finished eating the grain feed, they ate hay at the drum can that contained additional hay rather than at the trough for hay (P < 0.01). Plasma dopamine concentrations were higher in pen D than in pen C (P < 0.05), and serum triglyceride concentrations were higher in pen C than in pen GD (P < 0.05) during the installation of the drum can. After removal of the drum can, serum total cholesterol concentrations became higher in pen D and GD than in pen C (both P < 0.05). Average daily gain correlated positively with the frequency of eating hay at the drum can in pen D (r_s = 0.52, P < 0.01). In pen GD, the frequency of using the drum can correlated negatively with DO (r_s = ?0.59, P < 0.01). Carcass belly fat was thicker in pens D and GD than in pen C (both P < 0.01). In pen GD, the frequency of eating hay (r_s = 0.79, P < 0.01) and grooming at the drum can (r_s = 0.63, P < 0.05) correlated positively with the marbling score. Although social factor affected the steers using the drum can, installing it in the early fattening stage encouraged the steers to eat and groom there and resulted in better carcass characteristics through the prolonged physiological positive effects.     

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.     

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.     

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.     

DYNAMIC COMPUTED TOMOGRAPHY OF THE PANCREAS IN NORMAL DOGS AND IN A DOG WITH PANCREATIC INSULINOMA

To establish optimal imaging conditions for enhanced computed tomography (CT) for canine pancreatic tumors, 10 healthy beagles were subjected to dynamic CT. This technique was then applied to a dog with suspected insulinoma. The changes in mean peak enhancement and the delay time of the aorta and pancreas were determined. In normal beagles, maximal arterial and pancreatic CT enhancement was observed at 15 +/- 2 s (795 +/- 52 Housfield unit [HU]) and 28 +/- 9 s (118 +/- 16HU) after contrast medium injection, respectively. Multiphase enhanced CT was performed in a pug with suspected insulinoma using the CT protocol defined for the normal beagles with some parameters modified; the images were acquired at the arterial (14 s after contrast medium injection), pancreatic (after 28 s), and equilibrium (after 90 s) phases; scanning was followed by exploratory laparotomy. CT images were characterized by an enhanced mass in the left pancreatic lobe at the arterial phase, during which the difference between the CT values of the mass and normal pancreas was the highest. Histopathologic diagnosis of the pancreatic mass was insulinoma. Thus, it appears that enhanced CT imaging can be used to delineate the pancreas from a pancreatic mass, and it may be helpful in deciding the need for surgery.     

Comparative observations on the growth changes of the histochemical property and collagen architecture of the Musculus pectoralis from Silky, layer-type and meat-type cockerels

Growth‐related changes in the histochemical properties and collagen architecture of the Musculus pectoralis were compared among Silky, layer‐type and meat‐type cockerels. Histochemical and immunohistochemical methods were used and collagen architecture was studied using scanning electron microscopy. The total amount of collagen present was also measured. The diameter of type IIB myofibers was similar or rather larger in the layer‐type birds compared with the meat‐type. The collagen content was generally low for 5–10 weeks across the breeds and then increased in the other breeds except for Silky. In the perimysium, the collagen bundles gradually increased in size and the density of the fibrils also increased during growth. At 30 weeks of age, the layer‐type birds showed compact collagen bundles while the meat‐type had loose bundles. The endomysial collagen network appeared relatively denser in the meat‐type chicks compared to the others at week 1. At 30 weeks of age, compact and felt‐like structure of endomysium was shown by Silky and layer‐type chickens, while the meat‐type showed a relatively loose arrangement of tissue in the endomysial collagen. From these results, it appears that the meat‐type chicken can produce a large M. pectoralis with many, relatively thinner myofibers and a relatively undeveloped form of intramuscular collagen structure.