关键词: 饲料, 饲养标准, 磷, 磷酸盐, 环境影响

Abstract: 【Objective】Phosphorus (P) is one of the essential mineral elements for animals. It plays an important role in the growth, development and production of livestock. However, the efficiency of P in animal production is very low, a large amount of undigested feed P excreted with manure, and the P enrichment in the environment resulted in serious P pollution, such as eutrophication. Feed P level and phosphate supplementation are closely related to the P use efficiency and manure P excretion. The objective of this study is to determine the status of P level and phosphate application of animal feed in China, and to provide a scientific basis for rational use of feed P resource and reduce the excretion of manure P. 【Method】 The variance of the P requirement recommended by American feeding standard and Chinese feeding standard, the actual P content and phosphate supplementation in the feed were studied in this research by conducting literature analysis, surveys, and experiments. 【Result】 For swine, compared to the Chinese standard, the current American standard recommends the P requirements as total P, standardized total tract digestible (STTD) P, and apparent total tract digestible (ATTD) P, with no recommendation for non-phytate P (NPP). For laying hens, broilers, meat ducks, the American standard lists NPP requirements, but not total P requirement. For dairy cattle, the total P requirement recommended by the Chinese standard is 31%, 74%, and 26% higher than the American standard for heifers, milking cows, and dry cows, respectively. Compared to the American standards, the current Chinese feeding standard is higher in the NPP requirement for laying hens (0.32% vs 0.25%), slaughter chickens (0.35%-0.40% vs 0.30%-0.35%), and meat ducks (0.35%-0.42% vs 0.30%-0.40%). The majority of phosphates used in feed in China is dicalcium phosphate (DCP), then the mono-dicalcium phosphate (MDCP) and monocalcium phosphate (MCP). The contents of phosphate, total P and NPP of same feed produced by different enterprises varied greatly. The use of calcium phosphate in commercial feeds in China was 8.8 kg·t^-1 in 2016 on average, decreasing from 12.0 kg·t^-1 in 2006. Total P requirement of animals and poultry used by the feed industry in 2016 was similar to that used in 2006 based on surveys, consistent with the Chinese standards. However, the NPP requirement used by the feed industry was higher than recommended by both the Chinese standards and the American standards for laying hens, growing pigs, and finished pigs.【Conclusion】The P requirements of dairy cows, laying hen, later stage of broiler, and meat duck recommended by Chinese feeding standard were higher than the American standard; the use of calcium phosphate in commodity feeds in China was 3.2 kg·t^-1 in 2016 lower than in 2006 on average; the NPP requirement used by the feed industry was higher than recommended by both the Chinese feeding standards and the American feeding standards for laying hens, growing pigs, and finished pigs. It is suggested that the study of phosphorus requirement should be carried out based on the animal varieties and feed characteristics in China, and to modify the recommended standards for phosphorus requirement of animals. At the same time, we need to adopt the measures of using the low-phosphorus diets, the high utilization rate of calcium phosphate and addition of phytase in feed to improve the efficiency of feed phosphorus utilization, and to reduce the P excreted with manure.

Key words: feed, feeding standard, phosphorus, phosphate, environmental impacts