利用模糊规划技术为畜禽优化饲料配方

本文介绍一种新的饲料配方优化模型一模糊配方模型,利用该模型改进已有配方软件,并将该模型与已有模型进行比较和分析。     

ANALYSIS OF THE POTENTIOMETRIC TITRATION OF NATURAL AND SYNTHETIC POLYCARBOXYLATES

Potentiomctric titrations of a variety of natural and synthetic poly-COOH's varying in molecular weight and COOH density gave pKm values varying from 3.5 to 5.2. The pattern of carboxylic acid group dissociation is discussed in terms of purely electrostatic assumptions and of COOH group clustering. Synthetic polymaleic acid showed many of the characteristics of both fulvic and humic acids, and therefore seems to be a reasonable representation of an average, hypothetical soil organic matter polycarboxylic acid.     

The origin and loss of fractal scaling in simulated soil aggregates

A growing body of evidence supports the use of fractals to approximate the heterogeneous structure of soil. Fractal models of transport processes in soil indicate that the fractal dimension and the upper limit to fractal scaling (denoted ξ) determine flow rates and scaling properties. A two-dimensional Monte Carlo simulation of soil aggregation is used to identify the key processes which may lead to fractal-like scaling in the soil matrix. A bonding law is developed which parameterizes the relative importance of chemical bonding to binding by microbial by-products and fungi. We investigate the sensitivity of the fractal dimension and ξ to the nature of the bonding law, and to aggregate fragmentation, initial particle size distribution and mechanical restructuring. Fractal-like structures result from the aggregation process. However, the measured fractal dimension is insensitive to the detailed form of the bonding law. The factor that most sensitively influences the fractal dimension is found to be mechanical restructuring such as would arise from the action of roots, soil fauna and natural weathering. By contrast, ξ is most sensitive to the bonding law. The results suggest that the fractal dimension and characteristic diameter of aggregates should be uncorrelated, and that increased binding by microbial by-products and fungi should produce larger, less dense, aggregates.     

Utilization of (3S,3'S)-astaxanthin acyl esters in pigmentation of rainbow trout (Oncorhynchus mykiss)

The deposition of natural, optically active, astaxanthin fatty acid esters in rainbow trout ( Oncorhynchus mykiss ) was studied. Mono-esterified and di-esterified (3 S ,3' S ) astaxanthin were purified from the green microalga Haematococcus pluvialis and incorporated into extruded diets and compared with diets containing synthetic racemic astaxanthin (Carophyll Pink) and a total carotenoid extract from the alga. All sources of astaxanthin achieved >4 mg kg⁻¹ in the white muscle after 6 weeks feeding. No significant difference ( P  > 0.05) between the deposition of astaxanthin or total carotenoid for the different diets was observed. Other xanthophylls, namely lutein, zeaxanthin and idoxanthin were found in the white muscle of rainbow trout fed all diets and together accounted for 10–14% of total carotenoid. Astaxanthin was deposited in the white muscle in the stereochemical form administered in the diet, i.e. racemic astaxanthin for Carophyll Pink and ˜100% (3 S ,3' S )-astaxanthin for the algal sources. In contrast, epimerization of (3 S ,3' S ) astaxanthin from the alga was observed for the astaxanthin esters deposited in the skin of rainbow trout, with a ratio close to 1.0:2.0:1.0 (3 S ,3' S :3 R ,3' S :3 R ,3' R ).     

鸡传染性鼻炎的诊断和治疗

某鸡场产蛋鸡鸡群中部分鸡相继出现流鼻涕、打喷嚏、眼结膜发炎、一侧或两侧面部肿胀等症状.根据流行病学调查、临床观察、细菌学检查和分离菌株的生化及动物试验,确诊为鸡传染性鼻炎.通过药敏试验选用泰乐菌素和磺胺药治疗,并改善饲养管理,迅速控制了该病.