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Leather meal

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Datasheet

Description
Click on the "Nutritional aspects" tab for recommendations for ruminants, pigs, poultry, rabbits, horses, fish and crustaceans
Common names 

Leather meal, hydrolyzed leather meal, tannery by-product meal

Species 
Related feed(s) 
Description 

Before hides are tanned, the flesh and epidermis are removed by either hand or machine scraping. About 45 % of the weight of the hide is wasted: 5 to 10 % as waste hair, 5 to 10 % as dissolved proteins, 15 % as fleshings and trimmings and 15 % as splits. A fresh cattle hide contains 64 % water, 33 % protein, 2 % fat, 0.5 % mineral salts and 0.5 % other substances. The protein is composed mostly of collagen (88 %) and the rest is keratin (6 %), nonstructural protein (5 % of albumins. globulins, etc.). and elastin (0.9 %). To make leather, the tanner removes most of the noncollagenous materials (NRC, 1983). Leather scraps associated with the production of various leather products can be collected and hydrolyzed in a similar manner to poultry feathers. The by-product from this process is usually used as fertilizer, but it can be solvent extracted, dried and ground to a meal for animal feeding. and used as a supplemental protein source for livestock.

Nutritional aspects
Nutritional attributes 

The digestibility of unhydrolyzed leather meal is very low so it has little value as a feed. Normally CP content ranges from 70 to 75 %. Primarily used as a supplemental protein source for ruminant applications, since its amino acid profile is of quite low quality. Because of the poor amino acid profile care needs to be used when formulating diets to assure that the amino acid requirements of the animal that is being fed are being satisfied. Therefore, normally only low levels of leather meal are normally incorporated into diets, because of the poor balance of amino acids that it contains.

Limited research has been conducted evaluating the feeding characteristics of leather meal. It is very rich in glycine (> 20 % DM).

Potential constraints 

Chromium (Cr) is commonly added during the leather tanning process, therefore Cr poisoning is a potential problem when leather meal is fed as Cr level sometimes reaches toxic levels. The Cr level in the leather meals should not exceed approximately 2.75 %. Chromium can exist in several different forms and the form present in leather meal seems not to be absorbed really by animals and does not seem to accumulate in the meat or fat of animals consuming it (Waldroup et al., 1970). Still care should be taken when formulating rations.

Ruminants 

Hydrolyzed leather meal has been shown to be an acceptable source of crude protein for sheep fed at low levels of inclusion. Up to 6 % (75 % substitution for soybean meal) of leather meal can be fed without adversely affecting intake and animal health. Other than crude protein values which were lower at the 50 and 75 % substitution levels, apparent digestibilities of the ration components were not affected nor were rumen pH, volatile fatty acid or ammonia levels. The utilization of energy was affected only by a decrease in urinary energy. Chromium balance data were variable, but did not suggest extensive chromium retention (Knowlton et al., 1976).

Pigs 

Hydrolyzed leather meal, when substituted for soybean meal (SBM) at a level of 2 % of the diet, resulted in lowered rates of gain in swine (Nickelson et al., 1964). When leather meal replaced soybean meal in young (28 to 30 day old) growing swine diets, gains and feed conversion were improved and the incidence of scouring decreased (Kalous, 1986 [?]).

Poultry 

Vegetable-tanned leather trimmings were ground and added to broiler diets replacing 25 and 50 % of the fish meal and meat and bone meal, it was found that gain and feed conversion were less for the leather meal supplemented groups (Kalous et al., 1986). As the level of unhydrolyzed leather meal was increased (0, 3, 6, or 9%) in broiler diets gain and feed intake was reduced (Pinheiro et al., 1989). Its has been used to replace up to 25% of the soybean oil meal in poultry feed. It does not affect feed efficiency, but it tends to depress growth.

Fish 

Trout were fed leather meal up to 6-7 % without any depression in performance being observed (Eleraky, 1985).

Nutritional tables
Tables of chemical composition and nutritional value 

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 92.7 1.0 91.6 93.5 3
Crude protein % DM 71.7 3.5 68.3 75.4 3
Ether extract % DM 3.5 3.1 1.5 7.1 3
Ash % DM 20.9 18.6 23.2 2
Gross energy MJ/kg DM 17.7 1
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 22.0 1
Phosphorus g/kg DM 0.2 1
Magnesium g/kg DM 8.7 1
 
Amino acids Unit Avg SD Min Max Nb
Alanine % protein 10.0 1
Arginine % protein 9.0 1
Aspartic acid % protein 5.9 1
Glutamic acid % protein 9.6 1
Glycine % protein 25.5 1
Histidine % protein 0.5 1
Isoleucine % protein 1.6 1
Leucine % protein 3.1 1
Lysine % protein 3.9 1
Methionine % protein 0.8 1
Phenylalanine % protein 2.1 1
Proline % protein 13.1 1
Serine % protein 3.3 1
Threonine % protein 1.5 1
Tyrosine % protein 0.6 1
Valine % protein 2.4 1

The asterisk * indicates that the average value was obtained by an equation.

References

Knowlton et al., 1976; Waldroup et al., 1970; Wisman et al., 1961

Last updated on 24/10/2012 00:44:26

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 81.3 79.7 82.9 2
Crude protein % DM 82.2 79.4 85.1 2
Crude fibre % DM 0.9 0.0 1.8 2
Ether extract % DM 5.4 1.3 9.6 2
Ash % DM 8.6 5.3 11.8 2
Gross energy MJ/kg DM 22.0 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 38.4 1
Phosphorus g/kg DM 0.7 1
 
Amino acids Unit Avg SD Min Max Nb
Alanine % protein 10.4 1
Arginine % protein 7.2 1
Aspartic acid % protein 6.1 1
Glutamic acid % protein 10.8 1
Glycine % protein 22.8 1
Histidine % protein 0.6 1
Isoleucine % protein 1.7 1
Leucine % protein 3.3 1
Lysine % protein 3.8 1
Methionine % protein 1.3 1
Phenylalanine % protein 2.1 1
Proline % protein 14.3 1
Serine % protein 4.1 1
Threonine % protein 2.2 1
Tyrosine % protein 0.6 1
Valine % protein 2.8 1

The asterisk * indicates that the average value was obtained by an equation.

References

Pinheiro et al., 1989; Wisman et al., 1961

Last updated on 24/10/2012 00:45:39

References
References 
Datasheet citation 

DATASHEET UNDER CONSTRUCTION. DO NOT QUOTE. http://feedipedia.org/node/215 Last updated on October 20, 2011, 13:56

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