Effect of foliar application of oligochitosan with different molecular weight on growth promotion and fruit yield enhancement of chili plant

Oligochitosan (OC) is effective biostimulant on growth promotion and elicitation against disease infection for plants. However, the range of OC molecular weight that exhibits the most effective activity is not fully understood and requires further investigation. In this study, OCs with different weight average molecular weight (Mw) were prepared by gamma Co-60 irradiation degradation of chitosan in solution and the effect on growth promotion and enhancement of fruit yield of chili plant (Capsicum frutescens L.) by foliar application of OCs particularly with Mw of 7.8, 5.0, and 2.5 kDa was investigated. Chili plants, cultivated in a greenhouse were sprayed with OC concentration of 50 mg/L for three times. Results indicated that among treatments, OC with 2.5 kDa proved to be the best, which increased the shoot fresh weight by 71.5%, shoot dry weight by 184%, total chlorophyll content by 12%, and fruit fresh weight by 49.8% for the control. Thus, OC with low Mw (2.5 kDa) that can be suitably produced on large scale by gamma Co-60 ray irradiation degradation of chitosan solution is potentially promising to apply as a biostimulant to enhance chili fruit yield significantly.     

Changes in fineroot growth dynamics in response to phosphorus application in an Acacia mangium plantation in Vietnam

Fineroots (≤ 2 mm diameter) are dynamic components of the forest ecosystems and play important role in water and nutrient acquisition in forests. These roots are sensitive to forest fertilization and therefore, the response of fineroots to nutrient application would provide better understanding of the forest carbon and nutrient dynamics that will be helpful in sustainable forest management plans. Two fertilization treatments, including (1) F400: 400 g P₂O₅ (16.5%)/tree and (2) F600: 600 g P₂O₅ /tree, and F0: control (without fertilization), were applied in an Acacia mangium plantation with a planting density of 1100 trees/ha (3 m?×?3 m). The evaluation of fineroot growth across seasons showed that fertilization significantly increased production and subsequent mortality and decomposition. The total decomposition associated with F600 application was 7.95 tons ha^?1 year^?1, equaling 121% of F400 and 160% of the control. Mortality in F600 was 8.75 tons ha^?1 year^?1, equaling 111% of F400 and 198% of F0, while production in F600 was 10.40 tons ha^?1 year^?1, equaling 127% of F400 and 143% of F0. Fineroot production, mortality, and decomposition are seasonally dependent, with higher values measured in the rainy season than in the dry season. Stand basal area increment was significantly correlated with fineroot production (R²?=?0.75), mortality (R²?=?0.44), and decomposition (R²?=?0.48). This study showed that fertilization could facilitate fineroot production, which can then lead to a higher turnover of carbon and nutrients through the decomposition of the greater mass of the fineroots.

     

Evaluation of Diagnostic Tests for <Emphasis Type="Italic">Trypanosoma evansi</Emphasis> in Experimentally Infected Pigs and Subsequent Use in Field Surveys in North Vietnam and Thailand

This study is concerned with the evaluation of established diagnostic tests for diagnosis of Trypanosoma evansi in pigs. The immune trypanolysis test (TL), card agglutination test (CATT), latex agglutination test (LATEX), enzyme-linked immunosorbent assay (ELISA), microhaematocrit centrifugation technique (MHCT) and mouse inoculation (MI) tests were initially evaluated in experimentally infected fattening pigs. All infected pigs were confirmed parasitologically positive with both MHCT and MI. Results of the serological assays indicated that the TL could be a reference test for the presence of RoTat 1.2 antibodies in pigs. The results of the CATT and LATEX were inconsistent with the TL while the ELISA results correlated with the TL results. The four serological assays were subsequently used in two field surveys in Vietnam and Thailand. Results of the two agglutination assays (CATT and LATEX) were not consistent and did not correlate with TL results. The ELISA at percentage positivity of 22 appeared to have good ability to discriminate between seropositive and seronegative animals. Of the 437 samples collected at smallholder pig premises in northern Vietnam, no positive pigs were detected with the TL test. In Thailand, 77 samples were collected from five farrowing farms with a history of surra. Two parasitologically positive sows were found and on each farm seropositive sows were detected.     

Hepatocellular carcinoma with metastasis to the spleen in a Holstein cow

Hepatocellular carcinoma (HCC) with metastasis to the spleen in a Holstein cow was studied by histopathologic and immunohistochemical methods. The tumor was characterized by a pseudoglandular (acinar) pattern with an associated fibrous stroma. Individual cells often had a "hepatoid" appearance but were interspersed with scattered cells exhibiting a clear, periodic acid-Schiff (PAS)-positive cytoplasm and small eccentric nuclei. This pattern was present in nodules found in both liver and spleen. Moreover, hepatoid tumor cells were positive for alpha-fetoprotein. Immunohistochemical studies suggest that myofibroblasts were responsible for the production of fibrous septa surrounding the pseudoglandular structures of bovine HCC. In summary, our histologic and immunohistochemical findings support a diagnosis of primary HCC with splenic metastasis. Furthermore, the associated stromal response appears to be of a myofibroblast origin. The primary etiology of bovine HCC and the significance of the intralesional, PAS-positive clear cells remain undetermined.     

Effects of Energy and Protein Supplementation on the Production and Economic Efficiency of Scavenging Improved (Tamhoang) and Local (Ri) Breed Hens under Smallholder Conditions in North Vietnam

The objectives of this study were to evaluate the effects of supplementing maize meal and soybean meal, separately or mixed, on egg production performance of two breeds of scavenging hens under on-farm conditions. Treatments were: (1) confined, with a mixed feed (75% maize meal and 25% soybean meal) ad libitum (CMF); (2) scavenging, with a supplement of 60 g/bird per day of maize meal (ScM); (3) scavenging, with a supplement of 25 g/bird per day of soybean meal (ScS); (4) scavenging, with 54 g/ bird per day of the mixed feed (ScMF). Mean hen-day production was 21.8%, 19.8%, 17.7% and 22.8% for the CMF, ScM, ScS and ScMF treatments, respectively (p <0.05), and was significantly (p <0.001) higher for the improved Tamhoang breed (24.4%) than for the local Ri hens (16.7%). Mean egg weight was significantly higher for the Tamhoang (53.2 g) compared to the Ri hens (45.0 g) (p<0.01). Feed consumption per kilogram of eggs was significantly higher for the CMF treatment compared to the other treatments and was lower for the ScS compared to the other scavenging treatments (p <0.05). Feed cost per kilogram of eggs was lowest for the ScM treatment and was 30 to 40% higher for the confined treatment compared to the scavenging treatments. Feed consumption and cost of feed per kilogram of eggs were significantly lower for the Tamhoang than for the Ri hens.     

Short Communication Prevalence of Trypanosoma evansi in Water Buffaloes in Remote Areas in Northern Vietnam Using PCR and Serological Methods

Tropical Animal Health and Production -     

Mild hepatic fibrosis in cholesterol and sodium cholate diet-fed rats

To date, the majority of research on hypercholesterolemia has focused on the effects of a high cholesterol diet on atherosclerosis and coronary heart disease. The toxic effects of cholesterol on the liver and the relationship between the intake of a high cholesterol diet and hepatic fibrosis, however, have not been investigated clearly or histopathologically. Male Wistar rats were fed a diet supplemented with 1.0% cholesterol and 0.3% sodium cholate for 12 weeks. Rats were sacrificed and analyzed via blood biochemistry, traditional microscopy and immunohistochemistry. Following the feeding of this diet, the rates of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase and total cholesterol in the rats were elevated consistently from week 3 and throughout the remainder of the experiment. From microscopic observation, hepatic necrosis, macrophage infiltration and steatosis increased markedly throughout the experiment. Hepatic fibrosis and myofibroblast proliferation were detected at weeks 9 and 12. Mast cell appearance was proportional to the degree of hepatic damage. These findings suggest that hepatic fibrosis is inducible by a high cholesterol diet and is likely the result of the interaction between several different cell types (i.e., macrophages, myofibroblasts, and mast cells) in an inflammatory milieu. Hypercholesterolemia should be considered as a risk factor for hepatic fibrosis as well as atherosclerosis and coronary artery disease.     

Eosinophilic myositis in a slaughtered Korean native cattle

Histopathological findings of eosinophilic myositis in the carcass of a slaughtered Korean native cow are presented. Lesions contained massive fibrous septae with vacuolar changes in some lesions, and the hypercontraction and rupturing of muscle bundles, with replacement by eosinophils. Necrosis and severe eosinophil infiltration were observed. Sarcoplasmic fragmentation and atrophy developed. Typical of granuloma, calcified myofibers were focally surrounded by macrophages and numerous inflammatory cells, and multinucleated giant cell formation was evident.     

Shape memory effects of polyurethane block copolymers cross-linked by celite

The shape memory polyurethane (PU) copolymers cross-linked by celite, a porous inorganic material with enormous surface area and hydroxyl groups on the surface, were prepared to see if the shape memory effect and the mechanical properties were improved. The PU copolymers with different celite contents were compared and characterized by IR, DSC, DMA, and UTM. The melting temperatures of PU soft segment were around 20 oC independent of celite content. The shape memory effect and mechanical properties were dependent on the celite content, and the celite addition into the reaction mixture should be made in the middle of polymerization to get the best shape memory and mechanical properties. The best mechanical properties were found at 0.2 wt% celite content and its shape retention rate went up to 98 %. The inclusion of celite as a cross-linker increased both shape memory effect and mechanical properties. The reasons underlining the improvements by adopting celite as a cross-linker are discussed in this paper.