Enhanced phagocytic activity of neutrophils caused by administration of egg white derivatives (EWD) in cats injected with cyclophosphamide (CPA)

To examine in vivo effects of egg white derivatives (EWD), the numbers of peripheral blood cells and neutrophil phagocytosis were evaluated in cats injected intramuscularly with cyclophosphamide (CPA). There were no changes in the number of red blood cells (RBC) or packed cell volume (PCV) values regardless of oral administration of EWD or injection of CPA, but the numbers of platelets, white blood cells (WBC) and neutrophils in cats administered EWD significantly increased (p<0.05 to 0.01) when compared with those in control cats which received saline solution. In addition, the administration of EWD resulted in a significant enhancement in the phagocytic activity of neutrophils (p<0.01) when compared to control cats, suggesting that EWD has a stimulating effect on leukocyte progenitors. The numbers of platelets, WBC and neutrophils, and the phagocytic activity of neutrophils in cats injected with CPA alone were significantly lower (p<0.05 to 0.01) than those in control cats. However, co-administration of EWD to cats injected with CPA resulted in a significant increase in the numbers of platelets, WBC and neutrophils (p<0.05 to 0.01), and in the phagocytic response of neutrophils (p<0.01) when compared to cats injected with CPA alone. Therefore, these results suggest that co-administration of EWD may be effective in reducing some possible side effects in animals treated with immunosuppressive or antitumor agents.     

Effects of 6-hydroxydopamine on the development of the immune system in chickens

It has been suggested that the sympathetic nervous system communicates with lymphocytes expressing cell surface receptors for neurotransmitters such as norepinephrine (NE), on the basis of the finding that neurotransmitters modify immune responses in mammalian species. We confirmed that chicken lymphocytes in the brusa of Fabricius, thymus and spleen expressed beta-adrenergic receptor (beta-AR) mRNA from embryonic day (E) 10 and that intracellular cAMP level was elevated by NE, suggesting that lymphocytes express functional beta-AR on their surface at an early embryonal stage. To clarify whether the nervous system is involved in the development of the immune system, the effects of 6-hydroxydopamine (6-OHDA), one of sympathectomizing agents, on chicken lymphocytes was investigated. A single injection of 6-OHDA at a dose of 400 microg into a chicken embryo was carried out at E7 or 14 (as referred to E7 group and E14 group, respectively). NE level and the relative proportion of Bu-1a(+), CD4(+) and CD8(+) cells in the spleen of 3-week-old chickens were not altered by 6-OHDA treatment. However, the proliferative responses and expression of IL-2 mRNA in spleen cells cultured with pokeweed mitogen were reduced in E7 group compared with those of control. Furthermore, in CD8(+) spleen cells of E14 group of 3-week-old chickens, the expression of beta-AR mRNA and the relative increase of intracellular cAMP stimulated with NE were significantly decreased. These results suggest that the sympathetic nervous system affects the development of the immune system.     

Protective effects of sugar cane extracts (SCE) on Eimeria tenella infection in chickens

The effects of oral administration of sugar cane extracts (SCE) on Eimeria tenella oocysts infection in chickens were studied with 2 different experiments. In Experiment 1, 3-week-old inbred chickens (MHC; H.B15) were inoculated into the crop with SCE (500 mg/kg/day) for 1 day or 3 consecutive days, and then challenged with E. tenella sporulated oocysts (2 x 10(4) cells/chicken). In Experiment 2, 1-week-old chickens were orally administered SCE at the same dose for 3 consecutive days, and then initially infected with E. tenella sporulated oocysts (2 x 10(3) cells/chicken). At 2 and 3 weeks of age, these chickens were immunized intravenously with the mixed antigens of sheep red blood cells (SRBC) and Brucella abortus (BA). At 4 weeks of age, chickens were challenged with E. tenella sporulated oocysts (1 x 10(5)/chicken). Challenged chickens with E. tenella oocysts showed markedly decreased body weight gain/day, severe hemorrhage and great number of shedding oocysts in feces and high lesion scores. Oral administration of SCE and initial infection with oocysts (2 x 10 (3)/chicken) resulted in a remarkable improvement in body weight gain/day, hemorrhage, the number of shedding oocysts and lesion score, compare to other infected groups. In addition, SCE-inoculated chickens with the initial infection showed a significant increase in antibody responses against SRBC and BA and also improvement in decreased relative proportions of Bu-1a(+) and CD4( )cells in cecal tonsil lymphocytes of E. tenella-challenged chickens. Cecal tissues of chickens administered SCE and initially infected with E. tenella oocysts showed lower numbers of schizonts, gametocytes and oocysts than those of infected control chickens. These results suggest that SCE have immunostimulating and protective effects against E. tenella infection in chickens.     

Detection of mitogen-induced lymphocyte proliferation by bromodeoxyuridine (BrdU) incorporation in the chicken

3H-thymidine (3H-TdR) incorporation assay has been generally used to measure lymphocyte proliferation in the chicken. Disadvantages of this assay are that radioisotope is biological hazard to the person and environment and that it can not measure which subset of lymphocytes proliferates. In this study, bromodeoxyuridine (BrdU) incorporation assay by flow cytometry was compared with 3H-TdR incorporation assay. As a result, BrdU incorporation assay showed a strong correlation with 3H-TdR incorporation assay, and it could be applied simultaneously to detect BrdU incorporation and expression of cell surface marker antigens. These results suggest that the BrdU incorporation assay by flow cytometry is useful to analyze lymphocyte proliferation in detail.     

Immunostimulating and growth-promoting effects of sugar cane extract (SCE) in chickens

Polymorphonuclear cells of the peripheral blood in the chicken significantly increased their phagocytosis when cultured with sugar cane extract (SCE; 250-1,000 microg/ml) for 24 hr. Chickens orally administered SCE (500 mg/kg/day) for 3 or 6 consecutive days at 1 week of age showed significantly higher body weight and gain in body weight/day and a lower food conversion ratio within the growing period of 6 weeks than physiological saline-administered control chickens. Furthermore, oral administration of SCE also resulted in significantly higher immune responses against sheep red blood cells and Brucella abortus. These results suggest that SCE has immunostimulating and growth promoting effects in chickens.     

A split-root apparatus for examining the effects of hydraulic lift by trees on the water status of neighbouring crops

We describe a split-root system for examining the effects of hydraulic lift by trees on crop growth. In this system, upper lateral tree roots were grown in a container set on the ground through which the taproot of the tree could penetrate into the moist soil below. The container, with a radius of 0.5 m and a height of 0.20 m, consisted of two compartments divided by a waterproof barrier. A markhamia tree (Markhamia lutea (Benth.) Schumann) and upland rice (Oryza sativa (L.)) plants were planted in one compartment, with only rice plants planted in the other compartment. Irrigation of the container was ceased at the start of the experiment. The stomatal conductance of the rice plants in the associated side, in which both trees and rice plants were grown, declined more rapidly during the first drying period than in the rice-only compartment, suggesting that there was competition for water between the tree and the crop plants. However, during the later drying period, the rice plants in the associated side were green and viable, while those in the rice-only side became desiccated. Rice roots were seen intermingling with tree roots, and the soil water content in the associated site tended to be higher than in the rice-only side. It is likely that hydraulic lift occurred in the associated side and that water that had been transferred to the surface roots was released into the soil, enabling the rice plants in this compartment to remain viable. This novel system is useful for examination of the effects of hydraulic lift by trees on the growth of neighbouring crops. This revised version was published online in June 2006 with corrections to the Cover Date.     

Movement of the fluvial form of masu salmon, <Emphasis Type="Italic">Oncorhynchus masou masou</Emphasis>, in a mountain stream in Kyushu,Japan

Using mark-recapture methods, the movements of the fluvial form of masu salmon (Oncorhynchus masou masou) in a mountain stream on the island of Kyushu, Japan, were studied. Most (78%) of the masu salmon were recaptured in the pool in which they had been originally caught and tagged. Of those that moved between pools, the proportion of individuals that moved during the breeding period was not significantly higher than the proportion that moved during the non-breeding period. However, during the breeding period, a higher proportion of larger salmon moved than did smaller fish. The proportion of mobile large males during breeding period was higher than that for small males. Also, it was found that a few individuals showed long-range movement in the autumn. As a long-term movement, 78 individual fish (65%) that were recaptured more than three times showed high sedentary tendencies. Sixteen individual mobile fish (13%) moved and returned to the original pool. Fluvial form of masu salmon in Kyushu show a high sedentary nature; however, large mature males seem to actively move in search of female during breeding period.     

Growth of the fourspine sculpin <Emphasis Type="Italic">Cottus kazika</Emphasis> in the Gonokawa River,Japan, and effects of water temperature on growth

ABSTRACT:   The fourspine sculpin Cottus kazika is indigenous to Japan and found in Honshu except for the waters facing the Seto Inland Sea, and was also found in southern Shikoku and eastern Kyushu. This species has a catadromous lifestyle and migrates as juveniles from the sea to the middle reaches of rivers to grow. The growth pattern of this fish was investigated by a mark-and-recapture method from July 1994 to December 1996, in the Nigorikawa River, a tributary of the Gonokawa River system, Shimane Prefecture. 0-year-old fish of 50–70 mm total length ( TL ) occurred in the study area from June to July, grew to 90–140 mm  TL by the following April, and attained 160–210 mm  TL by December. This fish grew rapidly in September–November and April–July, almost ceasing to grow in July–September. It seems that this stagnant growth phase in summer is a characteristic of the seasonal growth pattern of C. kazika . A rearing experiment indicated that the growth rate of C. kazika was higher at 16–22°C than at 12–14 and 24–26°C. This result supports the field evidence of a stagnant growth phase in summer in the Nigorikawa River.