利用廉价蛋白源代替鱼饲料中鱼粉的研究进展

饲料费用占鱼类养殖成本的50％左右。饲料费用取决于饲料的价格和饲料系数,饲料价格往往取决于饲料中蛋白原料的价格,其中鱼粉是最昂贵的蛋白原料之一。利用廉价蛋白原料代替鱼饲料中的鱼粉可降低鱼类养殖的饲料成本,20世纪70年代以来国内外对此进行了大量研究,本文综述了针对鱼饲料中常见的几种廉价蛋白原料的利用方面取得的研究进展。     

利用廉价蛋白源代替鱼饲料中鱼粉的研究进展

饲料费用占鱼类养殖成本的50％左右。饲料费用取决于饲料的价格和饲料系数，饲料价格往往取决于饲料中蛋白原料的价格，其中鱼粉是最昂贵的蛋白原料之一。利用廉价蛋白原料代替鱼饲料中的鱼粉可降低鱼类养殖的饲料成本，20世纪70年代以来国内外对此进行了大量研究，本文综述了针对鱼饲料中常见的几种廉价蛋白原料的利用方面取得的研究进展。     

鸡肉丁冷冻干燥法的工艺及干燥模型

确定了鸡肉丁的冻干工艺条件，探讨了热烫、预冻速率、捕水器温度对制品品质与干燥时间的影响，建立了鸡肉丁冻干的传热传质模型，由模型计算出理论干燥时间，并与实验值进行了比较。     

Risk control effectiveness of phosphorus-containing passivators on Cd-contaminated agricultural soils to be strictly controlled

Purpose

Phosphorus (P)-containing passivators have a stabilizing effect on cadmium (Cd)-contaminated agricultural soils to be safely used, offering good potential for risk control of Cd-contaminated agricultural soils to be strictly controlled. In this study, an incubation experiment was conducted to evaluate the risk control effects of using hydroxyapatite (HAP) and monocalcium phosphate (MCP) on Cd-contaminated agricultural soils to be strictly controlled.

Materials and methods

Samples of topsoil were collected (0–20 cm) from agricultural land near a lead–zinc mine in Southwestern China containing 32.07 mg kg^?1 Cd with a pH of 7.28. The amounts of passivators added were equal to approximately 3% of the soil by weight. The soil Cd content, physicochemical properties, enzyme activity, and microbial community were analyzed.

Results

The results showed that the application of HAP and MCP decreased the activity and mobility of Cd in soils to be strictly controlled. HAP was more effective in decreasing the exchangeable Cd (Cd_Ex) than MCP (rate of decrease was 48.1% for HAP and 24.4% for MCP). According to the results of the geometric mean (GMean) and the integrated total enzyme activity (TEI) index, the total soil enzyme activity of the HAP treatment was higher than that of CK and MCP treatment. HAP and MCP significantly decreased the Chao and Shannon bacterial community indices and the Shannon index of the soil fungal community. HAP increased Actinobacteria abundance, which is beneficial to soil fertility enhancement and plant growth, and MCP increased Rhizobiales abundance, which promotes soil P cycling and plant growth. Primary driving factors for the changes in bacterial and fungal community composition in the stabilized soils were CEC and Cd_Ex for bacteria and Cd bound to carbonates (Cd_Car) and residual Cd (Cd_Res) for fungi.

Conclusions

HAP is more suitable for risk control of Cd-contaminated agricultural soils to be strictly controlled than MCP from the perspective of soil Cd activity and mobility, soil enzyme activity, and diversity and composition of the soil microbial community.