Nitrogen Budget and Ammonia Volatilization in Paddy Fields Fertilized With Liquid Cattle Waste

A study was conducted to determine nitrogen budget and ammonia volatilization in Japanese paddy fields supplemented with liquid cattle waste (LCW). A series of four, 2?×?10 m experimental plots was established in a paddy field with silty clay soil planted with forage rice (Oryza sativa L.). In addition to 195 kg N ha^?1 of chemical or compost-based basal fertilizer, LCW was applied as an additional fertilizer at total nitrogen rates of 0, 255, 255, and 405 kg N ha^?1 to the four plots C195, T450-1, T450-2, and T600, respectively. The mass balance showed that after application of LCW, 32–39% of total input nitrogen was assimilated into aboveground parts of rice plants, 11–15% leached downward, 2.5–4.0% was lost via ammonia volatilization, 1.6–5.1% was retained in roots or was adsorbed onto soil, and approximately 30–40% was lost via denitrification. Compared to animal waste slurries applied to unsaturated soils, nitrogen loss via ammonia volatilization was relatively lower, probably due to the dilution effect of floodwater. Nitrogen loss via denitrification was markedly higher in areas where LCW was applied compared to areas without LCW application. On the other hand, nitrogen leaching downwards represented a substantial loss and may be an environmental concern. However, after LCW application only, the ammonium ion was detected, at a maximum nitrogen concentration of 11.4 mg L^?1. In this system, therefore, nitrogen has a different fate to that in animal waste slurries applied to unsaturated soil. In that situation, the major nitrogen form in leaching water is nitrate nitrogen, which moves readily into groundwater.     

Epididymal stone formation and decreased sperm production in roosters vaccinated with a killed strain of avian infectious bronchitis virus

Our objective was to determine if vaccination with killed avian infectious bronchitis virus (AIBV) causes epididymal calcium stones in the rooster as is seen following vaccination with live attenuated AIBV. Specific-pathogen-free roosters were divided into three groups: nonvaccinated (NONVAC), live attenuated AIBV-vaccinated (LVAC), and killed AIBV-vaccinated (KVAC) groups. Roosters were vaccinated at 2, 6, 10, and 14 wk of age and the epididymal region was observed at 27 wk of age. Epididymal stones were present in 13% of NONVAC, 50% of KVAC, and 64% of LVAC roosters. Histologically, immune cells were seen in the interstitium of efferent ductules containing stones. We conclude that use of a killed vaccine does not reduce the incidence of epididymal stones.     

Novel antioxidative metabolites in rat liver with ingested sesamin

Sesamin, a major lignan in sesame oil, is known to have many biological activities, especially protective effects against oxidative damage in the liver. As sesamin itself has no antioxidative properties in vitro, to elucidate the mechanism of its antioxidative effects, the reaction products of sesamin in rat liver homogenate were analyzed. The methylenedioxyphenyl moiety in the structure of sesamin was shown to be changed into a dihydrophenyl (catechol) moiety. The enzymatic reaction products in vitro were identified as (1R,2S,5R,6S)-6-(3,4-dihydroxyphenyl)-2-(3,4-methylenedioxyphenyl)-3,7-dioxabicyclo[3,3,0]octane and (1R,2S,5R,6S)-2,6-bis(3,4-dihydroxyphenyl)-3,7-dioxabicyclo[3,3,0]octane, which showed strong radical scavenging activities; the latter was a novel compound. The same metabolites were found as glucuronic acid and/or sulfic acid conjugates in substantial amounts in rat bile after oral administration of sesamin. It is suggested that sesamin is a prodrug and the metabolites containing the catechol moieties in their structures are responsible for the protective effects of sesamin against oxidative damage in the liver.     

Expressions of protein oxidation markers, dityrosine and advanced oxidation protein products in Cisplatin-induced nephrotoxicity in rats

The purpose of this study was to evaluate whether dityrosine and advanced oxidation protein products (AOPP) reflect the severity of cisplatin-induced nephrotoxicity. Immunoexpression of dityrosine in kidneys and plasma AOPP concentration were examined up to day 4 post-cisplatin injection in rats. Cisplatin injection induced tubular injury on days 2-4 after injection and increased serum creatinine and BUN on days 3 and 4. On days 2-4, dityrosine was immunostained in the cytoplasm of damaged tubular cells, and their immunostaining intensity increased time-dependently. Plasma AOPP levels were significantly increased on days 3 and 4. These results suggest that expressions of dityrosine and AOPP were associated with the severity of renal injury and may be useful markers for the development of cisplatin-induced nephrotoxicity.     

Correlations between mitochondrial respiration activity and residual feed intake after divergent genetic selection for high‐ and low‐ oxygen consumption in mice

The aims of the present study were to identify the differences between two mouse lines (high (H)‐ and low (L)‐oxygen consumption) in terms of mitochondrial respiratory activity when GMP (glutamate, malate, and pyruvate) and succinic acid are used as substrates and to examine the relationship between mitochondrial respiration activity and feed efficiency in both lines. The average daily feed intake, feed conversion ratio (FCR), and residual feed intake (RFI) were significantly higher in the H than the L line. The correlation between FCR and RFI was significant (r = 0.60, p < 0.05). RFI was effective as an indicator of feed efficiency. When succinic acid was used as a substrate, mitochondrial respiration states 2–4, ACR, and proton leak were significantly higher in the H than the L line. When GMP was used as a substrate, respiration states 3 and 4 in the H line were significantly higher than those in the L line, and there were significant positive correlations between FCR and RFI and mitochondrial respiration states 2–4. The results indicated that selection for high or low OC changed the basal metabolic rates estimated from liver mitochondrial respiration activity and feed efficiency.     

Application of the slope‐ratio growth assay technique to estimate tryptophan availability in soybean meal fed to young rats

The slope‐ratio assay for rat was used to determine whether tryptophan (Trp) availability in soybean meal (SBM) is affected by the presence of other amino acids (AAs). In a preliminary study, rats were fed graded levels of Trp‐supplemented diets to establish the Trp concentration range over which the weight gain response was linear. This range was found to be from 0.04% to 0.12% Trp. Subsequently, rats were fed basal (0.045% Trp) or Trp‐supplemented diets from three different sources: l ‐Trp alone, SBM, or l ‐Trp mixed with other AAs to reflect AA levels in the test SBM (AA‐mix). Weight gain in rats increased linearly with supplemental Trp intake (p < .05) for all Trp sources. Compared to the slope achieved with l ‐Trp alone, the estimated availability of Trp in SBM was 84.4%, while for the AA‐mix it was 93.4%. It is evident that the 6.6% reduction in l ‐Trp availability in AA‐mix is due to metabolic costs derived from excess levels of other AAs beside Trp, given that the absorption of crystalline l ‐Trp in the small intestine is 100%. In conclusion, the Trp availability of SBM was estimated to be around 90.4% (i.e., 84.4/93.4 × 100) after correcting for the effects of the other AAs in SBM.     

Phyto-purification of livestock-derived organic waste by forage rice under subtropical climate

Soil and water pollution caused by organic waste is a concern for livestock-breeding areas. Nitrogen balance in a paddy-field water-purifying system in which cattle feces were applied was studied for 4 years to assess the suitability of the system for a subtropical area, Japan. Three successive harvestings using ratoon of forage rice following one rice transplanting were conducted with chemical fertilizer and high and low rates of cattle-feces application. Nitrogen load was 81.3–495.0 kg N ha^?1 year^?1, while nitrogen uptake was highly dependent on the yield of the first harvesting. Annual variation of forage rice yields was large, ranging from 15.5 to 26.8 Mg ha^?1 owing to fluctuation in the yield at second and later harvestings. On average, nitrogen was lost by leaching at a rate of 2.3–3.4 kg N ha^?1 year^?1. The nitrogen content in soil at a depth of 0–5 cm increased up to 12.2 kg N ha^?1 over the 4-year period compared with that before the field experiment. However, continuous application of cattle feces could slightly increase the nitrogen content in soil at a depth greater than 35 cm. Our results showed the ability of flooded forage rice to remove nitrogen at up to 320.1 kg ha^?1 year^?1 for a field to which cattle feces were applied. Further investigation is needed to produce a high and stable yield at second harvesting each year, to prevent the accumulation of soil nitrogen, and to assess gaseous nitrogen loss.