Animals, silica content

Sauer et al. (185) confirmed that in test animals the silica content of tissues was independent of silica concentration in the diet. In rats the silica content of muscles increased with age and then declined in old age. It was increased by caffeine (186). Silica in blood varied inversely with the level in muscle. 

The rice straw residue is seen to have limited intrinsic value indeed its presence is a barrier to the subsequent year s wheat crop. In southern parts of India it is sometimes collected for animal fodder, but it is poor food, being high in Silica content. If the farm is within 10 km of a green energy power plant, the straw could be collected for energy production similarly proximity to a paper manufacturer affords a market for the straw. However, most of the straw has no market, and approximately 12 million toimes is burnt aimually in Punjab alone (Sood 2013). 

Animal fat was studied using sweep codistillation (Brown et al. 1987). Good recovery (90%) was measured at 0.4 mg/kg no LOD information was given. Diazinon in liver and rumen content was determined by GC/FPD after methanol/dichloromethane (1 9) extraction and clean-up using either gel permeation chromatography (GPC) or silica gel solid phase extraction (SPE). The LODs were reported to range from 10 to 50 pg/g using a 5 g sample with measured recoveries of diazinon from rumen content of 95% at 0.1 pg/g and from liver of 88% at 0.05 pg/g. 

Lipids, relatively nonpolar chemical substances found in plant, bacterial, and animal cells, are among the most ubiquitous of biomolecules. In this experiment, a lipid extract of ground nutmeg will be purified by chromatography on a silica gel column. Analysis of the lipid extract by thin-layer chromatography will provide the classification of the components in the extract. The unknown lipids will be further characterized by saponification and analysis of the fatty acid content by gas chromatography. For an abbreviated experiment, students may be provided samples of natural oils and fats that can be analyzed by saponification and gas chromatography. 

Defluoridized apatites are obtained by sintering apatite in the presence of water vapor, silica and other substances. The world capacity (mainly in the USA and former States of the USSR) for this type of product, with a P2O5 content of ca. 42% is estimated to be 1.5 10 t/a. Defluoridized apatite is also used as an animal nutrition supplement. 

Because of high titanium concentrations in soils and the widespread use of titanium oxide as a pigment, the toxicity of titanium oxide to animals has been the subject of much investigation. The results show that titanium oxide is not toxic. Intratracheal administration of ilmenite to rats led to slight fibrogenicity, due to the silica, aluminum oxide and iron oxide contents of the titanium concentrate. Likewise, a small... 

Several types of evaporators may be used for SPA production, but the most popular is a forced-circulation system (Figure 11.25) developed by the Swenson E apo-rator Co, In production of superphosphoric acid (69%-72%) P2O5) by concentrating wet-process add, most of tbe fIuo.rine is volatilized so that the acid contains only 0.2%-0.3% F. By adding reactive silica during evaporation to enhance fluorine volatilization, the fluorine content can be further decreased to about 0.1%. Such acid is suitable for the manufacture of animal-feed supplement products, such as dicalcium phosphate or ammonium phosphate, and is used for that purpose. Other advantages of superphosphoric acid are ... 

In many of the intensive rice-growing areas of the world, particularly Asia, this straw is used as a food for farm animals. Its protein content and metabolisable energy value are similar to those of spring barley straw. It has an exceptionally high ash content, about 170 g/kg DM, which consists mainly of silica. The lignin content of this straw, about 60-70 g/kg DM is, however, lower than that of other cereal straws. In contrast to other straws, the stems are more digestible than the leaves. 

The two main by-products obtained from rice milling are the hulls and rice meal. The hulls are high in fibre content and can contain up to 210 g/kg DM of silica. They also have sharp edges, which may irritate the intestine and should never be given to animals. Rice meal or rice bran comprises the pericarp, the aleurone layer, the germ and some of the endosperm, and is a valuable product containing about 120-145 g crude protein/kg DM and 110-180 g oil/kg DM. The oil is particularly unsaturated and may become rancid very quickly if it is removed, a product, extracted rice bran, of better keeping quality is obtained. The amounts of oil, crude protein and crude fibre in rice meal sold in the UK must be declared. 

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