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51.
Milk and meat products derived from ruminants contain a mixture of positional and geometric isomers of C18:2 with conjugated double bonds, and cis‐9, trans‐11C18:2 (conjugated linoleic acid, CLA) is the predominant isomer. The presence of CLA in ruminant products relates to the biohydrogenation of unsaturated fatty acids by rumen bacteria. Although, it has been suggested that cis‐9, trans‐11 CLA is an intermediate that escapes complete ruminal biohydrogenation of linoleic acid, is absorbed from the digestive tract, and transported to tissues via circulation. Its major source is endogenous biosynthesis involving Δ9‐desaturase with trans‐11C18:1 produced in the rumen as the substrate. CLA has recently been recognized in animal studies as a nutrient that exerts important physiological effects, including anticarcinogenic effects, prevention of cholesterol‐induced atherosclerosis, enhancement of the immune response, reduction in fat accumulation in body, ability to enhance growth promotion, antidiabetic effects and improvement in bone mineralization. The present review focused on the origin of CLA in ruminant products, and the health benefits, metabolism and physiological functions of CLA.  相似文献   
52.
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 (rs = 0.52, P < 0.01). In pen GD, the frequency of using the drum can correlated negatively with DO (rs = ?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 (rs = 0.79, P < 0.01) and grooming at the drum can (rs = 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.  相似文献   
53.
The aim of the present study was to clarify the ovarian and hormonal dynamics after the aspiration of follicular fluid in cows with follicular cysts. Follicular fluid was aspirated from the follicular cysts and follicles that were fated to become cystic follicles and other coexisting normal follicles, respectively, in lactating cows (n = 3). After the aspiration procedure, new follicles developed and reached a diameter of 25 mm without ovulation within 13–19 days. The plasma concentrations of inhibin decreased and follicle-stimulating hormone increased rapidly after the aspiration procedure, and subsequently increased and decreased, respectively, as a new follicle grew. No luteal structures developed after the aspiration procedure, and the animals’ plasma progesterone levels remained low. The present study indicates that the cystic follicles are never luteinized by the aspiration of follicular fluid, and consequently, new follicular cysts are observed to repeatedly develop.  相似文献   
54.
The aim of this study was to examine whether increased frequency of luteinizing hormone (LH) pulses influences luteal progesterone (P4) secretion by measuring progesterone concentrations at the secreted (caudal vena cava) and circulating levels (jugular vein) in lactating dairy cows. Cows received six intravenous administrations of 2.5 μg of GnRH (gonadorelin acetate, n=4) or 2 ml saline (n=3) at 1-h intervals on 12.4 ± 0.4 (mean ± SE) days after ovulation. Blood samples were collected from the caudal vena cava and jugular vein every 12 min for 12 h (6 h before and after treatment). During the 6 h after treatment, frequency of LH pulses (5.3 ± 0.3 and 3.0 ± 0.0 pulses/6 h) and mean LH concentration (0.50 ± 0.06 and 0.38 ± 0.05 ng/ml) were greater (P<0.05) in GnRH-treated cows than in saline-treated cows. Mean P4 concentration and amplitude of P4 pulses in the caudal vena cava during the 6 h after treatment were greater (P<0.05) in GnRH-treated cows than in saline-treated cows, but the frequency of P4 pulses was not different between the groups. Mean P4 concentration in the jugular vein during the 6 h after treatment was also higher (P<0.05) in GnRH-treated cows than in saline-treated cows (7.0 ± 1.3 and 5.4 ± 0.9 ng/ml). These results indicate that the increased frequency of LH pulses stimulates progesterone secretion from the functional corpus luteum and brings about higher P4 concentrations in the circulating blood in lactating dairy cows.  相似文献   
55.
中性松香施胶剂的制备及施胶特性   总被引:5,自引:1,他引:5  
本研究制备了多种烃基松香酯-松香施胶剂及松香甘油酯-松香施胶剂,并对其在中、碱性造纸施胶中的应用进行了探讨。施胶结果表明,松香甘油酯-松香施胶剂能有效地用于中、碱性施胶,然而其它烃基松香酯-松香施胶剂在同样条件下却无施胶效果。这意味着中性松香胶施胶剂的制备及性能并非完全取决于松香羧基的改性而是松香酯的结构有关。虽然碱性填料碳酸钙的添加引起一定程度的施胶效果的下降,松香甘油酯-松香中性施胶剂在含有碳  相似文献   
56.
A total of 568 normal feces from calves on a beef farm in Fukui Prefecture, Japan, in 2011–2012 were examined by RT-semi-nested PCR for rotavirus A (RVA) VP4 genes. Through partial sequencing and BLAST analyses of 84 VP4-positive specimens, we identified an avian-like RVA strain, N2342, which shares highest nucleotide identity (80.0%) with known avian-like bovine strain 993/83, in one specimen. Phylogenetic analysis also revealed a close genetic relationship between N2342 and avian RVAs, suggesting bird-to-cattle transmission. We observed frequent contact of wild birds with calves in the farm, suggesting that these birds were the source of the virus.  相似文献   
57.
58.
ABSTRACT: To reveal the ontogeny of pancreatic exocrine function in the early larval stage of eel, cDNAs encoding major pancreatic enzymes, trypsinogen, amylase and lipase were identified from the Japanese eel Anguilla japonica and their expression pattern in larvae was analyzed. The cloned eel trypsinogen precursor consisted of 224 amino acids and showed 82.2% identity to trypsinogen-2 of winter flounder Pleuronectes americanus . The eel amylase precursor consisted of 512 amino acids and showed 77% identity to winter flounder amylase. Eel pancreatic lipase was composed of 470 amino acids and had 58.3% of identity to human pancreatic lipase. In the eel larvae, mRNA expression of trypsinogen and amylase was first detected at 6 days post-hatching (d.p.h.), and the expression level increased between 7 and 8 d.p.h. In contrast, mRNA expression of lipase was first detected at 8 d.p.h. Eel larvae start to feed actively at 8 d.p.h. Thus, it was indicated that eel pancreas starts to synthesize digestive enzymes at 6 d.p.h. and acquires full function by the onset of exogenous feeding at 8 d.p.h.  相似文献   
59.
The effects of supplementation with cellulase, xylanase, pectinase, hemicellulase, glucanase, phytase and protease of microbial origin on digestibility of crude protein (CP) and dry matter (DM) of soybean meal in vitro were examined in the present study. Changes in viscosity during in vitro digestion were also examined as an index of carbohydrate digestibility. Hemicellulase and all enzyme combinations without protease showed significant improvement of CP digestibility. Cellulase, xylanase, phytase and glucanase tended to improve CP digestibility. Dry matter digestibility was improved significantly by pectinase and all enzyme combinations. Cellulase and phytase tended to improve DM digestibility. Crude protein and DM digestibilities were the highest when all the enzymes except protease were added. Protease, cellulase, pectinase, xylanase, glucanase and hemicellulase significantly reduced viscosity, while phytase had no effect on viscosity. Viscosity was increased unexpectedly when all the enzymes were added. These results strongly suggest that a combination of carbohydrases improves the CP and DM digestibility of soybean meal while protease inhibits the actions of these enzymes. The present study also suggests that viscosity is not always a good index of digestibility. Moreover, excluding the protease from commercial crude enzyme preparations may improve digestibility.  相似文献   
60.
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.  相似文献   
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