Within 1 to 3 weeks after the application of liquid livestock feces, the soil benzyloxycarbonyl‐l‐phenylalanyl‐l‐leucinase (z‐FLase) and caseinase activities in upland fields (120 t feces ha−1 year−1, 600 t feces ha−1 year−1) increased to the maximum levels (z‐FLase 562 pKat and 840 pKat g−1 dry soil, respectively; caseinase 1,018 pKat and 2,141 pKat g−1 dry soil, respectively), and decreased to the original level after 5 weeks. Numbers of culturable bacteria counted on albumin medium (AA), bacteria counted on peptone‐polymixin medium (PP), and vegetative cells of Bacillus spp. counted on BTV medium (BTV) also increased to the maximum levels after application of the feces. Although there was a significantly high correlation between bacterial number on AA and both the soil protease activities (z‐FLase, r=0.895; caseinase, r=0.935), more significant correlations were observed between bacterial number on AA and inorganic nitrogen contents (NH4+ content, r=0.902; NO3− content, r=0.981). Similarly, although a significant correlation was observed between the soil caseinase activity and bacterial number on PP (r=0.835) and BTV (r=0.780), and the number of fluorescent Pseudomonas spp. (P1) (r=0.867), more significant correlations were observed between the numbers of these culturable bacteria and the soil NH4+ content (PP, r=0.944; BTV, r=0.959; P1, r=0.933) and soil NO3− content (PP, r=0.982; BTV, r=0.961; P1, r=0.990). Therefore it was difficult to identify the bacterial group responsible for the soil protease production based on these correlation analyses. Rapid increase in the total bacterial number (AA) by the 600 t application was mainly due to the increased number of bacteria on PP medium, which were assumed to have been introduced from liquid livestock feces.

No abstract

The nutrient content of the leaves of sweet potato cultivar Koganesengan was determined to be 35.0 kcal energy, 89.0 g water, 3.9 g protein, 0.8 g fat, 1.0 g carbohydrates, 1.2 g minerals, and 4.1 g dietary fiber/ 100 g fresh weight. The polyphenol content of the leaves was 11.5 g chlorogenic acid equivalents per 100 g dry weight. Some reports have described that the consumption of dietary fiber and polyphenols is effective in treating dyslipidemia. Therefore, we investigated the influence of sweet potato leaves on lipid metabolism in rats fed a high-fat diet. After 35 days of rearing, the weight gain and adipose tissue weight were lower in the rats fed a high-fat diet supplemented with sweet potato leaves than in those not fed sweet potato leaves. Plasma triglyceride and total cholesterol levels, and liver total cholesterol level were significantly lower in rats fed sweet potato leaves compared to rats fed the high-fat diet alone. These results suggested that the simultaneous intake of sweet potato leaf and the high-fat diet inhibited the excessive accumulation of adipose tissue in rats.

No abstract