Analysis animal, digestibility

Samples of animal bones weighing approximately 3 g are ashed at 600 °C until the entire bone is ash-white. Samples are then crushed in a mortar and pestle. A portion of the sample is digested in HCl and diluted to a known volume. The concentrations of zinc and strontium are determined by atomic absorption. The analysis for strontium illustrates the use of a protecting agent as La(N03)3 is added to prevent an interference due to the formation of refractory strontium phosphate. 

The ability to identify and quantify cyanobacterial toxins in animal and human clinical material following (suspected) intoxications or illnesses associated with contact with toxic cyanobacteria is an increasing requirement. The recoveries of anatoxin-a from animal stomach material and of microcystins from sheep rumen contents are relatively straightforward. However, the recovery of microcystin from liver and tissue samples cannot be expected to be complete without the application of proteolytic digestion and extraction procedures. This is likely because microcystins bind covalently to a cysteine residue in protein phosphatase. Unless an effective procedure is applied for the extraction of covalently bound microcystins (and nodiilarins), then a negative result in analysis cannot be taken to indicate the absence of toxins in clinical specimens. Furthermore, any positive result may be an underestimate of the true amount of microcystin in the material and would only represent free toxin, not bound to the protein phosphatases. Optimized procedures for the extraction of bound microcystins and nodiilarins from organ and tissue samples are needed. 

Lavoisier said that Phosphorus is met with in almost all animal substances and in some plants which, according to chemical analysis, have an animal nature.. . . The discoveiy that M. Hassenfratz has made of this substance in wood charcoal would make one suspect that it is commoner in the vegetable realm than has been thought tins much is certain that, when properly treated, entire families of plants yield it (37). Apothecary J. K. F. Meyer of Stettin wrote in 1784 that he had observed, several years previously, a permanent green color in the essences he prepared by digesting green herbs in copper vessels He concluded that phosphates in the leaves had reacted with the copper to form copper phosphate (38). 

The application of high-sensitivity ICP-MS detectors coupled to HPLC has enabled the detection of trace arsenic compounds present in marine animals. Thus, arsenocholine has been reported as a trace constituent (<0.1% of the total arsenic) in fish, molluscs, and crustaceans (37) and was found to be present in appreciable quantities (up to 15%) in some tissues of a marine turtle (110). Earlier reports (46,47) of appreciable concentrations of arsenocholine in some marine animals appear to have been in error (32). Phosphatidylarsenocholine 45 was identified as a trace constituent of lobster digestive gland following hydrolysis of the lipids and detection of GPAC in the hydrolysate by HPLC/ICP-MS analysis (70). It might result from the substitution of choline with arsenocholine in enzyme systems for the biogenesis of phosphatidylcholine (111). 

A method using micro-LC/tandem MS was developed for analysis of the tryptic digest containing the intramolecular albumin lysine-lysine adduct, which enabled the detection of exposure of human blood to > 1 xM phosgene in vitro. The method has not yet been applied to animal or human samples. 

The molar ratios of most of the amino acids in the protein of the German cockroach are generally similar to those of vertebrates and other invertebrates with respect to whole animal protein hydrolyzates (1). However, histidine, lysine, tyrosine, leucine, isoleucine, valine, and alanine are somewhat more abundant in cockroach protein and there is less cystine. The data vary significantly from data previously reported on the amino acid composition of the German cockroach (7). The earlier analysis, however, was conducted on insects with the entire head and digestive tract removed and the remaining portions of the body extracted with lipide solvents only. 

Enhancing the Se levels in crops can be achieved by adding organic amendments (manure of Se-supplemented farmed animals) or inorganic Se to mineral fertilizers [116, 117]. The use of sodium selenate-enriched fertilizers in Finland resulted in increased Se levels in different foods and, consequently, the average serum Se in the population improved over the period 1984 D1988. ICP-MS was used to study the feasibility of wheat enrichment by selenate addition to soil fertilizers [118]. AE-HPLC-ICP-MS was optimized for the separation of selenite, selenate, selenocysteine, and selenomethionine. Total Se determination and speciation analysis were performed in water extracts and in enzymatic digests of wheat samples. It was shown that a major part of the selenate taken up by cereals was converted to selenomethionine. 

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