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Thaikua S.,Kagoshima University | Ebina M.,Japan National Agriculture and Food Research Organization | Kouki K.,Okinawa Prefectural Livestock and Grassland Research Center | Inafuku M.,Okinawa Prefectural Livestock and Grassland Research Center | And 4 more authors.
Grassland Science | Year: 2015

In vitro dry matter digestibility (IVDMD) is one of the most important traits for grass quality improvement. Analysis of IVDMD in laboratory with a large number of breeding populations is very laborious. The objectives of this study were to evaluate IVDMD of brachiariagrass germplasm as material in breeding program, and also to determine the appropriate selection criteria for high digestibility. IVDMD (pepsin-cellulase method), morphology traits and water content of 17 genotypes of Brachiaria spp. (B. brizantha, B. decumbens, B. ruziziensis and Brachiaria hybrid) were evaluated at two harvesting times, winter and early summer seasons. The correlations among traits were determined, and their heritability were also estimated. IVDMD ranged from 48.9 to 59.0% in winter, and 42.9 to 54.4% in early summer. Among morphological traits, leaf-stem index (ratio of leaf width/stem diameter) showed the highest correlation with whole plant IVDMD (r = 0.74) followed by leaf-shape ratio (leaf width/leaf length; r = 0.72), and leaf water content also highly correlated with whole plant IVDMD (r = 0.79). The broad sense heritability of IVDMD and the related traits of two harvests combination were high with the range of 0.75-0.93. The results demonstrate that leaf-stem index, leaf-shape ratio and water content could be the useful selection criteria for the breeding of brachiariagrass for high digestibility. © 2015 Japanese Society of Grassland Science.

Waki M.,Japan National Agriculture and Food Research Organization | Yasuda T.,Japan National Agriculture and Food Research Organization | Suzuki K.,Japan National Agriculture and Food Research Organization | Sakai T.,Saga Prefecture Livestock Experiment Station | And 11 more authors.
Bioresource Technology | Year: 2010

This paper presents a quantitative investigation and analysis of anammox activity in sludge taken from biological swine wastewater treatment plants. An incubation experiment using a 15N tracer technique showed anammox activity in sludge taken from 6 out of 13 plants with the rate ranging from 0.0036 μmol-N2/g-VSS/h to 3.1 μmol-N2/g-VSS/h, and in a biofilm with the highest activity at 25.8 μmol-N2/g-VSS/h. It is notable that 9 out of 11 sludges in which the pH was maintained between 6.6 and 8.1 retained anammox activity, while those with either a lower or higher pH did not. Moreover, anammox-positive sludge had a significantly higher concentration of NO2- s(-) N plus NO3- s(-) N than did anammox-negative sludge. A significant difference was not observed between anammox-positive and -negative sludge regarding BOD / NH4+ s(-) N in the influent, DO concentration in aeration tanks, and the concentrations of NH4+ s(-) N, free nitric acid, and free ammonia. © 2009 Elsevier Ltd. All rights reserved.

Okazaki T.,Livestock Research Institute | Ikoma E.,Livestock Research Institute | Tinen T.,Okinawa Prefectural Livestock and Grassland Research Center | Akiyoshi T.,Livestock Research Institute | And 2 more authors.
Animal Science Journal | Year: 2014

Oxytocin (OXT) contained in boar semen is known to produce uterine contraction; therefore, we hypothesized that the co-injection of OXT with sperm would improve artificial insemination (AI) using liquid or frozen-thawed boar sperm. We initially examined whether OXT added to semen extender improved sperm transport to the oviduct. Although the addition of OXT did not affect the fresh or frozen-thawed sperm motility or acrosomal integrity, it significantly increased the number of sperm in the oviduct at 6h after AI injection with OXT, as compared with the control (P<0.05). Moreover, some sperm were observed in the sperm reservoir of the isthmus in the OXT treatment group, whereas few sperm were observed in the control. When OXT was added to the semen extender immediately prior to AI, the conception rates were significantly higher in both fresh semen and frozen-thawed semen than in the control group (P<0.05: liquid, 87.5% vs. 70.5%; frozen-thawed, 89.8% vs. 75.0%). From these results, we concluded that the addition of OXT to the semen extender assisted in sperm transportation from the uterus to the oviduct, which resulted in improved reproductive performance. © 2013 Japanese Society of Animal Science.

Tsuruta S.-I.,Japan National Agriculture and Food Research Organization | Tsuruta S.-I.,Japan International Research Center for Agricultural science | Shimoda K.,Japan National Agriculture and Food Research Organization | Shimoda K.,Japan International Research Center for Agricultural science | And 3 more authors.
Japan Agricultural Research Quarterly | Year: 2015

Tropical grasses have been widely utilized as warm-season grasses in the warm temperate zone since the early 20th century because of their high yields as well as for perennial forages in their native tropical areas. The high yield of tropical grasses is mainly due to C4 photosynthesis. However, the soaring demands for animal production sparked by economic development in tropical countries mean genetic improvement of such grasses is urgently needed. Considerable breeding efforts have been made to create and develop new tropical grass cultivars, although direct selection from natural populations remains the main method used for breeding. Cross-breeding has not proliferated due to a lack of genetic information concerning the polyploidy, high sterility, outcrossing, and apomixis of these grasses, although several of these difficulties are starting to be resolved by advanced research using molecular biology tools. These tools are an effective means of achieving genetically improving of tropical grasses, and further development is anticipated. In this review, achievements in the improved guineagrass, brachiariagrass, sorghum, and zoysiagrass are introduced and discussed.

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