Beneficial effects on meat quality of yellowtail Seriola quinqueradiata induced by diets containing red pepper

The meat quality of farmed yellowtail Seriola quinqueradiata fed on extruded pellets (EP) containing 0.5% (v/v) red pepper (experimental group) was compared with yellowtail of the same age fed on EP (control group). In 1-year-old yellowtail, the crude lipid content of the dorsal muscle of the experimental group tended to be lower than that of the control group. In contrast, there was no difference in the lipid content of the dorsal muscle between the control group and the experimental group in 2-year-old yellowtail. The muscle texture of the experimental group was significantly firmer than that of the control group, with the effect of red pepper unrelated to fish age and lipid content. Color change of red muscle of the experimental group was significantly lower than that of the control group, and the content of thiobarbituric acid-reactive substances in the red muscle was significantly lower in the experimental group than in the control group. These results are the first to demonstrate that the inclusion of red pepper in the diet is able to reduce the loss of muscle texture firmness and to slow down color change in red muscle of yellowtail.     

Induction of estrus by prostaglandin F2alpha administration in the vaginal vestibules of miniature pigs

Estrus induction is an important step in embryo production. It has been difficult to induce estrus in miniature pigs by intramascular (i.m.) injection of prostaglandin F2alpha (PGF2(2alpha)) in the early luteal stage of the estrous cycle. In the present study, we injected two different doses of PGF2(2alpha) i.m. and into the submucosa of the vaginal vestibule (i.ves.) of miniature pigs, and examined the effect of these treatments on estrus induction. Fifteen miniature pigs were divided into five experimental groups (control, saline injected i.m.; PGF2alpha treated, 1.0 or 1.5 mg of PGF2alpha injected twice i.m. or i.ves.), and the estrus length and concentrations of 17beta-estradiol (E2) and progesterone (P) in the blood were examined. Estrus length was significantly shortened by a large amount of PGF2alpha injected i.ves. In addition, the concentration of P in the blood significantly decreased after two injections of PGF2alpha (i.m. or i.ves.). These results suggest that in miniature pigs, administration of at least 3.0 mg of PGF2alpha is required for the induction of luteolysis and injection of PGF2alpha into the vaginal vestibule is a useful method of estrus induction.     

Effects of carbamate, BPMC, on the central cholinergic functions and behavior of mice

O-sec-butylphenyl methylcarbamate (BPMC), an anticholinesterase carbamate, was injected once (100 mg/kg, s.c.) or repeatedly (50 mg/kg/day for 10 days) into mice. Animals were examined for their behavior and for parameters of cholinergic activity in the forebrain. Mice that received only a single injection exhibited reduced ambulation, hypothermia, and impairment of rotarod performance for up to 3 hr after a single injection. BPMC increased levels of acetylcholine (ACh) in the forebrain for up to 6 hr, and decreased acetylcholinesterase (AChE) activity for up to 24 hr. Both high-affinity choline uptake (HACU) and binding of [3H]quinuclidinyl benzilate (QNB) were reduced 20 min after a single injection without any effect on choline acetyltransferase (ChAT) activity. In behavioral tests conducted 10 min prior to the daily injections, rotarod performance and ambulation were slightly impaired for a few days before and after cessation of injection. Repeated treatment decreased HACU and binding of [3H]QNB for 24 hr after the final injection without any changes in levels of ACh content, AChE activity and ChAT activity. BPMC may reversibly impair cholinergic functions through effects not only on AChE activity but also on HACU and binding of [3H]QNB.     

Characterization of new monoclonal antibodies against porcine lymphocytes: molecular characterization of clone 7G3, an antibody reactive with the constant region of the T-cell receptor delta-chains

A battery of mouse monoclonal antibodies (mAbs) reactive with porcine peripheral blood (PB) leukocytes was generated. Among the mAbs, 6F10 was found to react probably with cluster of differentiation (CD)8 alpha-chain, while 7G3 and 3E12 were found to recognize gammadelta T-cells, as revealed by two-color flow cytometric and immunoprecipitation studies. 7G3 was shown to react with the constant (C) region of the T-cell receptor (TCR) delta-chain by the following facts: (1) 7G3 immunoprecipitated full-length TCR delta-chain protein fused with glutathione S-transferase (GST) produced by Esherichia coli and (2) 7G3 reacted with TCR delta-chain expressing Cos-7 cells transfected with either full-length or N-terminal deleted mutant cDNA, but did not react with Cos-7 cells transfected with C-terminal deleted mutant TCR delta-chain cDNA. All three mAbs produced high-quality immunostaining results on frozen sections, revealing a distinct distribution of gammadelta T-cells and CD8(+) cells. This report precisely characterizes mAbs against porcine TCR for the first time, facilitating molecular biological investigations of the porcine immune system.     

Ventilation of seawater during bleeding suppresses the occurrence of burnt meat in yellowtail <Emphasis Type="Italic">Seriola quinqueradiata</Emphasis>

Fifteen farmed yellowtail Seriola quinqueradiata were randomly selected from sea cages. Five fish were slaughtered instantly by cutting the spinal bulb (control group). The remaining ten fish were left for 20 min in a narrow net and then they were slaughtered by cutting the spinal bulb instantly. These ten fish were bled in two water tanks. In one tank, the water was aerated (ventilation group), while the other tank was not aerated (burnt group). The ATP ratio in the control group (83.8 ± 4.1%) was higher than the ventilation group (37.2 ± 22.1%) and the burnt group (5.8 ± 6.0%) at 3 h after slaughter. The K value of the burnt group increased remarkably at 3 h after slaughter, and was significantly higher than those for the other groups. The ventilation group showed a recovery in available energy for physiological maintenance to the same level as the control group during bleeding, as well as a significantly slowed loss of muscular firmness compared to the burnt group. This study shows that the yellowtail continued to respire and take up oxygen until complete physiological death, and elevated oxygen levels during bleeding slowed the postmortem changes and suppressed the occurrence of burnt meat.     

Variations in the proximate composition of muscle in cultured yellowtail Seriola quinqueradiata at different anatomical portions

In this study, we examined differences in the proximate composition of five major muscles of the yellowtail, as well as the relation between seasonal variations in the levels of crude lipids and texture of these muscles. The differences in content among these muscles and the variations in each muscle were greater for crude lipid and moisture content than for crude protein content. The crude lipid content of Musculus latero-dorsalis correlated with that of M. carinatus dorsalis, M. latero-ventralis, M. carinatus ventralis, and red muscle. In M. latero-dorsalis, the crude lipid content started to increase in October, remained high from November to January, started to decrease in March, and was low from April to June. The firmness of M. latero-dorsalis increased from October to November and started to decrease in March. Firmness decreased concurrently with decreases in crude lipid content and increased concurrently with increases in crude lipid content. The results of this study suggest that it is possible to predict the proximate compositions of other yellowtail muscles from the proximate composition of M. latero-dorsalis. Seasonal variation in crude lipid content of the M. latero-dorsalis was found, and variations in crude lipid tended to parallel those in firmness.     

Accumulation of lipofuscin in broiler chicken with wooden breast

Lipofuscin is one of the indicators of oxidative stress. To elucidate the role of oxidative stress in the development of wooden breast, this study investigates lipofuscin accumulation in various parts of wooden breast muscles. Sampling was performed using 46-day-old broiler chickens housed at a commercial Japanese poultry slaughterhouse. Fourteen wooden breast fillets and 13 normal breast fillets were collected in the deboning line. The samples used to measure shear force, 2-thiobarbituric acid reactive substance (TBARS), and for histological analysis were taken from the six portions of breast muscle fillets. In muscles affected by wooden breast, vacuolated muscle fibers were observed, and connective tissues appearing like perimysium were expanded with fibrosis. TBARS value and accumulation of lipofuscin were significantly higher in the wooden breast than in the normal breasts. A lot of lipofuscin granules were localized in the cytoplasm of collapsed muscle fibers of the wooden breast. The cranial portion of the wooden breast showed the highest shear force. The cranial position had a large amount of connective tissue and lipofuscin granules. The results of the present study strongly suggest that high oxidative stress, especially with a significant accumulation of lipofuscin, is associated with the development of wooden breasts.     

Reduction of urinary nitrogen excretion and ammonia emission from slurry by feeding a low protein diet supplemented with apple pomace to growing pigs

An experiment was conducted to determine the effects of supplementing a reduced crude protein (CP) diet with apple pomace on the urinary nitrogen excretion and ammonia emission from slurry in the growing pigs. Four barrows (35 kg bodyweight) were assigned to one of two diets. Each pig was placed in a metabolism cage and fed a low CP, amino acid-supplemented diet (CP 11.33%; low CP diet) or a low CP, amino acid-supplemented diet containing 23.08% dried apple pomace (CP 9.47%; apple pomace diet) for two 14-day experimental periods. After the completion of the first period, the pigs were switched to the other diet. Urine and feces were quantitatively collected daily for 5 days after a 9-day adaptation period. The daily nitrogen intake for the low CP diet and the apple pomace diet was 17.76 g/pig and 18.64 g/pig, respectively. The pigs fed the apple pomace diet excreted more fecal nitrogen (6.86 g/day) than the pigs fed the low CP diet (3.63 g/day) ( P  < 0.001), but urinary nitrogen excretion with the apple pomace diet was 3.11 g/day, which was much lower than that for the low CP diet (5.95 g/day) ( P  < 0.001). The daily ammonia emission from the mixture of urine and feces determined by an in vitro method was much lower for pigs fed the apple pomace diet (120 mg) than that for pigs fed the low CP diet (603 mg) ( P  < 0.01). The addition of apple pomace to a reduced CP, amino acid-supplemented diet reduces urinary nitrogen excretion and thereby ammonia emission.     

Photosynthesis of the rice plant under water stress

Leaf-resistance values sharply decreased after sunrise, remained low during daytime, and increased sharply toward sunset. This general pattern was modified by weather conditions and soil-water stress. On a cloudy day, leaf resistance remained low (3-5 s/cm) during daytime regardless of the soil-water regime. No increase in leaf resistance equivalent to “midday closure of stomates” was observed under flooded conditions on a sunny day. Under water stress and on a sunny day, leaf resistance began to increase in the morning or afternoon, depending on the degree of water stress. Both the light intensity at which the leaf photosyn-thetic rate reached light-saturation and the maximum value of the photosynthetic rate became lower as water stress became more severe. A simulation model revealed that crop photosynthesis was almost identical (17-18 g·m^-2·day^-l) for both water-stressed and well-watered crops on a cloudy day when solar radiation was 200 cal·cm^-2day^-l. On a sunny day, when solar radiation was 600 cal·cm^-2day^-l, however, crop photosynthesis under water stress reached its maximum at about 8 a.m., after which it declined with time and became almost zero after 12 noon. Under flooded conditions, diurnal changes in crop photosynthesis were similar to those of incident solar radiation. As a result, crop photosynthesis was about 33 g·cm^-2day^-l under flooded conditions and only about 10 g·cm^-2day^-l under water stress. Thus, crop photosynthesis under water stress was greater by 70% on a cloudy day than on a sunny day. This suggests that a partly shaded environment favors crop growth under water stress.     

A porcine lymphoma-derived cell line co-expressing IgM,IgG and IgA

A cell line (PL38PB) was established from blood samples of a 6-month-old pig that was diagnosed with lymphoma with CD5 expression. Histopathological examination revealed neoplastic lesions in the spleen, liver and lymph nodes. Tumor cells were immunohistochemically positive for CD20 and immunoglobulin heavy chains (μ, γ and α). Membranous CD5 and cytoplasmic Immunoglobulin M (IgM), ​Immunoglobulin G (IgG) and ​Immunoglobulin A (IgA) were detected in PL38PB cells by flow cytometry. In addition, the cytoplasm of PL38PB cells were positive for IgM, IgG and IgA by immunofluorescent. However, no Ig secretion was detected in culture supernatant by Ouchterlony gel diffusion method. Results suggest that PL38PB cells express three Ig isotypes that are produced but not secreted.