Animal protein concentrates

A European Council decision of 4 December 2000, which remains in force but under review, defined processed animal proteins as meat and bone meal, meat meal, bone meal, blood meal, dried plasma and other blood products, hydrolysed proteins, hoof meal, horn meal, poultry offal meal, dry greaves, fishmeal, dicalcium phosphate and gelatin. It directs that member states shall prohibit the use of processed animal proteins as food for farmed animals that are kept, fattened or bred for the production of food for human beings. Rshmeal may be given to non-ruminants, and the prohibition does not apply to milk and milk products. 

Although animal foods based on mammalian meat are prohibited from being used as food for farmed animals in the UK and Europe, there are areas where this may be allowed. For this reason, we have decided to include a few general comments on the nutritive value of such products. It may also be that, at some future date, current prohibitions on their use in Europe may be lifted. 

The protein of meat by-products is of good quality (BV approximately 0.67 for adult man) and is particularly useful as a lysine supplement. Unfortunately, it is a poor source of methionine and tryptophan. Various unidentified beneficial factors 

Values of 0.58 for r = 0.02,0.44 for r = 0.05 and 0.38 for r = 0.08 (r = passage rate from the rumen see p. 325) have been quoted for the rumen degradability of fishmeal protein, and it is pre-eminent as a source of undegradable protein for ruminant animals, although EU legislation currently bans its use. 

The protein contents of various fishmeals vary over a range of about 500-750 g/kg, but the composition of the protein is relatively constant. It is rich in the essential amino acids, particularly lysine, cystine, methionine and tryptophan, and is a valuable supplement to cereal-based diets, particularly where they contain much maize. The essential amino acid composition is compared with that of ideal protein (see Table 13.7 in Chapter 13) in Box 23.3. 

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Animal protein concentrates are used primarily in small amounts to make good deficiencies of certain Indispensable amino acids, minerals and B vitamins in the diets of non-ruminant animals. 

The normal level of inclusion of SDP in the diet is 20-80 g/kg, and at this high level and as a source of protein it would normally be included in Chapter 23 under animal protein concentrates, ffowever, it is thought that the product has growth-promoting properties beyond its use as a supply of digestible amino acids. 

In general, nonconventional protein foods must be competitive with conventional plant and animal protein sources on the bases of cost delivered to the consumer, nutritional value to humans or animals, functional value in foods, sensory quality, and social and cultural acceptability. Also, requirements of regulatory agencies in different countries for freedom from toxins or toxic residues in single-cell protein products, toxic glycosides in leaf protein products, pathogenic microorganisms, heavy metals and toxins in fish protein concentrates, or inhibitory or toxic peptide components in synthetic peptides must be met before new nonconventional food or feed protein products can be marketed. 

The nutrient sparing effect of antibiotics may result from reduction or elimination of bacteria competing for consumed and available nutrients. It is also recognized that certain bacteria synthesize vitamins (qv), amino acids (qv), or proteins that may be utilized by the host animal. Support of this mode of action is found in the observed nutritional interactions with subtherapeutic use of antibiotics in animal feeds. Protein concentration and digestibiHty, and amino acid composition of consumed proteins may all influence the magnitude of response to feeding antibiotics. Positive effects appear to be largest... 

Protein-Based Substitutes. Several plant and animal-based proteins have been used in processed meat products to increase yields, reduce reformulation costs, enhance specific functional properties, and decrease fat content. Examples of these protein additives are wheat flour, wheat gluten, soy flour, soy protein concentrate, soy protein isolate, textured soy protein, cottonseed flour, oat flour, com germ meal, nonfat dry milk, caseinates, whey proteins, surimi, blood plasma, and egg proteins. Most of these protein ingredients can be included in cooked sausages with a maximum level allowed up to 3.5% of the formulation, except soy protein isolate and caseinates are restricted to 2% (44). 

Iron transport agents may belong to the protein or non-protein class. In the former group are found the animal proteins transferrin (25), lactoferrin (26) and conalbumin (27). The low molecular weight iron carrying compounds from microorganisms, the siderochromes, may occur with or without a bound metal ion. Typically, severe repression of biosynthesis of these substances can be expected to set in at an iron concentration of ca. 2 x 10-5 g atoms/liter (28). Most, but not all, of these substances can be described as phenolates or hydroxamates (4). 

Several properties of hepatic microsomal AHH activity were compared in control and DBA-pretreated male little skates as shown in Table I. Following treatment there was an approximately 35-fold increase in specific enzyme activity, as quantitated by fluorescence of the phenolic metabolites formed (3, 21). The pH optimum, which was fairly broad, and the concentration of benzo(a)-pyrene (0.06 mM) that had to be added to the incubation mixture to achieve maximum enzyme activity were the same for both control and induced skate hepatic microsomes. The shorter periods observed for linearity of product formation with microsomes from the induced skates is thought to be related to the much higher AHH activity present, and may be due to substrate depletion or the formation of products which are inhibitory (i.e., compete with the MFO system as they are substrates themselves). A similar explanation may be relevant for the loss of linear product formation at lower microsomal protein concentrations in the induced animals. 

Since the caseins differ in lysine content (14, 24, 11 and 9 residues for asl-, xs2-, / - and tc-caseins, respectively) they have different dye-binding capacities. This feature may be of some commercial significance in connection with dye-binding methods for protein analysis if the ratio of the caseins in the milks of individual animals varies (as it probably does). It should also be considered when calculating the protein concentration of zones on electrophoretograms stained with these dyes. 

Even though liquid whey has been successfully commercialized in the form of alcoholic and nonalcoholic beverages, these are still a rarity in most countries. Most whey is converted to whey solids as ingredients for human food or animal feeds by traditional processes such as spray drying, roller drying, concentration to semisolid feed blocks, or production of sweetened condensed whey. Jelen (1979) reported other traditionally established processes including lactose crystallization from untreated or modified whey, production of heat-denatured whey protein concentrate, or recovery of milk fat from whey cheese in whey butter. ... 

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