DE2661020C2 - Feed mixture containing zinc bacitracin and proteolytic enzymes and its use - Google Patents

Description

The subject of the main patent according to DE-PS 26 33 106 is a feed mixture with an optimal composition in terms of its nutritional components, based on carbohydrates, protein, fats and optionally conventional additives as well as a content of an antibiotic and proteolytic enzymes, characterized in that 5-20 ppm zinc bacitracin are contained as the antibiotic and the proteolytic enzymes are contained in such an amount that an enzymatic activity of 0.05-2.5 mTU/g is present, where one enzyme unit (TU) is the amount of enzyme that releases cleavage products from a casein solution in one minute that have the same extinction as a 1 mol/l tyrosine solution. This feed composition produces improved results in terms of feed utilization and/or the weight gain achieved thereby compared to conventional high-performance feed mixtures that only contain antibiotics or enzymes alone.

Feedstuffs containing enzymes are known in principle from DE-AS 10 84 123. This describes a protein and starch-containing supplementary feed for suckling piglets aged less than 8 weeks. The enzymes described are fungal proteases or bacterial proteases and/or fungal amylases or bacterial amylases. There is no reference to the particularly beneficial effect of feed mixtures that have an enzyme activity in a precisely defined range on the one hand and a content of antibiotics on the other.

However, as has now been discovered, the addition of antibiotics and enzymes according to the main patent can also be used to produce feed mixtures whose content of crude protein, essential amino acids and metabolizable energy is up to 20% below the standard required for the respective animal species. Such feed mixtures then correspond to normal feeds in terms of growth and feed utilization results. This result is extremely surprising and leads in particular to a saving in protein and essential amino acids, which represent a significant cost factor in feed mixtures.

The invention therefore relates to a feed mixture based on carbohydrates, protein, fats and optionally additives, with a content of 5-20 ppm of the antibiotic zinc bacitracin and such an amount of proteolytic enzymes that an enzymatic activity of 0.05-2.5 mTU/g is present, where one enzyme unit (TU) is the amount of enzyme which releases cleavage products from a casein solution in one minute which have the same extinction as a 1 mol/l tyrosine solution, according to DE-PS 26 33 106, characterized in that a feed mixture has a deficit of protein and essential amino acids of up to 20%, based on corresponding complete feed mixtures.

The antibiotic zinc bactriacin belongs to the group of polypeptide antibiotics. The commercial preparations are mixtures of various polypeptides with a zinc content of up to 20%. The original form bactriacin is produced in a known manner by strains of Bacillus licheniformis.

Suitable proteolytic enzymes are obtained primarily by culturing microorganisms and separating them from the nutrient solutions. The processes for this are known. For example, proteolytic enzymes from Bacillus licheniformis, Bacillus natta, Bacillus subtilis, etc. are used. Acidic proteases are particularly preferred, e.g. from Aspergillus niger or from Rhizopus rhizopodiformis in accordance with DE-OS 25 28 490. Such proteases have a particularly broad spectrum of activity in the weakly acidic range between pH 2.5-6.5.

Commercially available feed mixtures are composed as optimally as possible for the specific needs of the individual animal species. The basis is carbohydrates, mainly from grain components, corn or similar. The main sources of protein are soya meal, fish meal, animal meal, bran and the like. Missing amino acids, e.g. methionine, can also be added. Fats are added in the form of vegetable or animal fats or waste fats.

Salts such as dicalcium phosphate, calcium carbonate and table salt are also added to build up the body. If necessary, the feed mixture is rounded off by adding trace elements, vitamins, fibre, etc. Substances produced by fermentation such as single-cell proteins from petroleum fractions or alcohols, various yeasts, algae protein or other substances, possibly also obtained from waste materials, can also be a significant part of the feed recipe.

Normally, for example, the protein content of a chicken fattening feed for the feeding period up to an age of 4-6 weeks is about 22%, the lysine value about 1.2%. A recipe equivalent in terms of fattening performance according to the invention, on the other hand, contains about 18-20% crude protein and 1-1.1% lysine, with an addition of 5-20 ppm, preferably 10-15 ppm zinc bacitracin and 0.05-2.5 mTU/g, preferably 0.2-0.5 mTU/g of a proteolytic enzyme, preferably an acid fungal protease. Feed mixtures of this type, but without antibiotics and enzyme additives, inevitably lead to poor growth and feed utilization results. They have therefore not been able to be used in practice to date. The addition of antibiotics, however, compensates for this growth and utilization depression. performs at the same level as a standard feed. This creates the conditions for the use of such low-quality feed rations in intensive livestock farming. The resulting protein savings represent a significant economic advantage and an important contribution to securing protein supplies.

The feed mixtures claimed have proven to be particularly effective for rearing broiler chickens. However, they can also be useful for all other animal species where the use of the antibiotics mentioned alone is already beneficial, for example in pig fattening and as feed for laying hens.

The antibiotic is preferably added to the feed in the form of a premix, e.g. bound to soya meal. When using meal-like feed compositions, the enzyme component is also applied as a premix. Any feed component, e.g. soya meal, acts as a carrier substance. When using steam-pelleted feed, the enzymes must be added in a suitably stabilized form in order to prevent deactivation by moisture and heat during pelleting. Such a process is the subject of DE-OS 26 02 260, for example.

To determine the enzyme unit (TU), the proteolytic activity of the protease is determined according to the well-known Anson principle: a suitably diluted amount of enzyme solution is incubated at 40°C for 20 minutes with an equal volume of a 1.2% casein solution containing 0.6% lactic acid, 6 mol/l urea and 0.1 mol/l citric or acetic acid. The pH of the casein solution is adjusted to 4.5 by adding 2 mol/l sodium hydroxide solution. After incubation, 0.4 mol/l trichloroacetic acid is added in a volume ratio of 1:1, the precipitate of undigested casein that forms is filtered off and the protein fragments formed during degradation in the filtrate are determined using any protein determination method. The method described by Layne in Methods in Enzymology 3 (1957) pages 448 ff. is suitable for this.

A blank value must be prepared for each sample, in which trichloroacetic acid is first added and then casein solution. This blank value indicates, in addition to the reagent blank value, the proportion of low molecular weight peptides that are already present in the enzyme solution before digestion. The difference between the main value and the blank value is then compared with the extinction in the specified method, which is a measure of the proteolytic activity of the enzyme present: one enzyme unit (TU) is the amount of enzyme that releases cleavage products from a casein solution in one minute that have the same extinction as a 1 mol/l tyrosine solution. The usual value is mTU = 10 ^-3 TU.

example 1

360 male day-old chicks of Lohmann origin were fed in barn systems for 6 weeks with 3 different feed mixtures according to the following experimental plan:
Ration I:
21% crude protein, 1.2% lysine, 0.86% methionine and cystine, 12 ppm zinc bacitracin, without enzyme. (complete mixture with antibiotic)
Ration II:
18% crude protein, 1.08% lysine, 0.82% methionine and cystine, 12 ppm zinc bacitracin, without enzyme. (low-quality mixture with antibiotic)
Ration III:
As II, but with the addition of 0.3 m TU/g acid proteases from Aspergillus niger or Rhizopus rhizopodiformis (according to DE-OS 25 28 490) (low-value mixture with antibiotic and enzyme)

After completion of the experiment, the final weight of the animals and the feed utilization were determined. "Feed utilization" is understood to mean the ratio of feed consumption to gain. Feed composition (%): Result: &udf53;ta:9:12:15:18&udf54;&udf53;tz5,5&udf54;&udf53;tw,4&udf54;&udf53;sg8&udf54;\\Ration&udf50;I\Ration&udf50;II\Ration&udf50;III&udf53;tz&udf54;&udf53;tz5,10&udf54;&udf53;tw,4&udf54;&udf53;sg9&udf54;\Final weight (g)\ 1353\ 1254\ 1367&udf53;tz&udf54; \Feed utilization\ 1.95\ 2.03\ 1.94&udf53;tz&udf54;&udf53;tz&udf54;&udf53;te&udf54;

Claims (3)

1. Feed mixture based on carbohydrates, protein, fats and optionally conventional additives, with a content of 5-20 ppm of the antibiotic zinc bacitracin and such an amount of proteolytic enzymes that an enzymatic activity of 0.05-2.5 m TU/g is present, where one enzyme unit (TU) is the amount of enzyme which releases cleavage products from a casein solution in one minute which have the same extinction as a 1 mol/l tyrosine solution, according to DE-OS 26 33 106, characterized in that the feed mixture has a deficit of protein and essential amino acids of up to 20%, based on corresponding full-value feed mixtures. 2. Feed mixture according to claim 1, characterized in that the proteolytic enzymes are acid proteases with an activity spectrum between pH 2.5-6.5. 3. Use of feed mixtures according to claims 1 and 2 for rearing broilers.