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Nitrogen (N) and phosphorus (P) use and losses in China's food chain have accelerated in the past three decades, driven by population growth, rapid urbanization, dietary transition, and changing nutrient management practice. There has been little detailed quantitative analysis of the relative magnitude of these driving forces throughout this period. Therefore, we analyzed changes in N and P flows and key drivers behind changes in the food (production and consumption) chain at the national scale from 1980 to 2010. Food (N and P) consumption increased by about fivefold in urban settings over this period but has decreased in rural settings since the 1990s. For urban settings, the integrated driving forces for increased food consumption were population growth, which accounted for ∼60%, and changing urban diets toward a greater emphasis on the consumption of animal products. Nutrient inputs and losses in crop and animal productions have continuously increased from 1980 to 2010, but the rates of decadal increase were greatly different. Increased total inputs and losses in crop production were primarily driven by increased crop production for food demand (68-96%) in the 1980s but were likely offset in the 2000s by improved nutrient management practices, as evidenced by decreased total inputs to and losses from cropland for harvesting per nutrient in crop. The contributions of animal production to total N and P losses to waters from the food chain increased by 34 and 60% from 1980 to 2010. These increases were caused mainly by decreased ratios of manure returned to cropland. Our study highlights a larger impact of changing nutrient management practice than population growth on elevated nutrient flows in China's food chain., (Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.)

Milk production has greatly increased in China recently, with significant impacts on the cycling of nitrogen (N) and phosphorus (P). However, nutrient flows within the changing dairy production system are not well quantified. The aim of this study was to increase the quantitative understanding of N and P cycling and utilization in dairy production through database development and simulation modeling. In 2010, of the entire 1987 and 346 thousand tons (Gg) of N and P input, only 188 Gg N and 31 Gg P ended up in milk. The average N and P use efficiencies were 24 and 25%, respectively, at the whole system level. Efficiencies differed significantly between the four dairy systems. Losses of N from these systems occurred via NH volatilization (33%), discharge (27%), denitrification (24%), NO leaching and runoff (16%), and NO emission (1%). Industrial feedlots use less feed per kg milk produced than traditional systems, and rely more on high-quality feed from fertilized cropland; they have very poor recycling of manure nutrients to cropland. As industrial feedlot systems are booming, overall mean N and P use efficiencies will increase at herd level but will decrease at the whole dairy production system level unless manure N and P are used more efficiently through reconnecting China's feed and dairy production sectors., (Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.)

The development of cachexia may complicate cancer therapy, yet controversy exists concerning its nutritional management. For example, use of total parenteral nutrition (TPN) may not be appropriate because of gut atrophy, possible stimulation of tumor growth, and lack of total host protein repletion. In the present experiment, host and tumor responses were compared after identical parenteral or enteral nutritional supplementation (EN). Eighteen days after subcutaneous inoculation of adult male Fischer-344 rats with fresh methylcholanthrene-induced sarcoma (tumor-bearing [TB] rats), catheters were placed into either the external jugular vein or the stomach. Four days later, rats were started on an 11-day course of either TPN or EN with a Freamine-III-based formula (amino acids = 6%, dextrose = 21.5%, lipid = 1.5%). When the rats were killed, there was no difference in tumor weight between the various TB groups. Carcass weight was increased significantly in both the TB-TPN and TB-EN groups, and there was an elevation in gastrocnemius protein content in both groups compared with the TB-rat food group. Small intestine protein was preserved in the TB-EN group to the level observed in the control-rat food animals. Total lipids in the liver were increased in both TB-TPN and TB-EN groups; however, the magnitude of the increase was less in the TB-EN animals. Neither treatment resulted in complete protein repletion of tumor-bearing rats. EN may be more appropriate than TPN in that gut mass is preserved. The maintenance of gut mucosa may prove to be beneficial in the treatment of the depleted, immunocompromised, and metabolically stressed host.

Treatment of tumor-bearing (TB) and control rats with the anabolic beta-2 agonist drug clenbuterol (CLE) for 14 days reduced food intake for 4 days initially. Feeding was increased in anorectic TB rats, however, during the last 7 days of drug administration. Since minimal muscle savings were observed in chow-fed TB rats treated with CLE, the anabolic effects of this drug were investigated in a second experiment on TB rats maintained on total parenteral nutrition (TPN). Sixteen days after the subcutaneous transplantation of methylcholanthrene-induced sarcomas rats was begun on a 2-week schedule of TPN. One group of these rats was treated daily for 14 days with CLE, while the remaining rats received injections of saline. Additional groups of TB and nonTB rats were maintained on rat chow for this period and treated with saline. Although TB rats maintained on rat chow or TPN and treated with saline exhibited significantly decreased gastrocnemius muscle weight and protein content, treatment of TB-TPN rats with clenbuterol normalized muscle mass and increased muscle protein content significantly and increased plasma concentrations of branched-chain amino acids. These results indicate that although nutritional support of TB organisms does not result in protein repletion, the addition of an anabolic drug renders the nutritional support highly efficacious.