BIOCIDAL COMPOSITIONS COMPRISING LACTIC ACID AND AT LEAST ONE OTHER ACID SELECTED FROM FORMIC ACID, ACETIC ACID AND PROPIONIC ACID
This invention relates to the use of biocidal compositions comprising a blend of acids for use as a medicament for animals, especially pigs, at the same time promoting growth thereof and improving the digestibility of amino acids fed to such animals. 5 It is known from prior published patents that antibiotics can be administered to animals to protect them from infection such as eg E. coli. However, antibiotics are relatively expensive and they have to be administered in vary controlled amounts. In order to avoid such an expensive method of protecting animals, a composition comprising benzoic acid or a derivative of
10 benzoic acid capable of giving rise to free benzoic acid in vivo has been proposed for use as a medicament for animals. WO 96/24248 (corresponding to EP-A- 808101) refers to the use of a combination of benzoic ester (0.2-30 % w/w) and 50-99.8% w/w of an unsubstituted or substituted C1-C4 monocarboxylic acid which is preferably formic, acetic, propionic or lactic acids or mixtures thereof and
15 is most preferably formic acid or a mixture of formic acid and propionic acid (page 3, lines 1-8) in antimicrobial compositions in order to enable penetration of microbial cells by benzoic acid. However, benzoic acid has relatively low solubility in aqueous systems. Therefore, an attempt has been made to find an antibiotic composition having greater solubility in water than benzoic acid and yet is just as 0 inexpensive and effective as benzoic acid.
It has now been found that a biocidal composition comprising a blend of acids substantially free of benzoic acid or a derivative thereof can be used instead of relatively expensive antibiotics for such animals and furthermore, such acid/salts have the advantage of being able to promote growth, decrease feed conversion and 5 improve digestibility of amino acids in animal feeds.
Accordingly, the present invention is a biocidal, antibiotic composition substantially free of any ester of unsubstituted or substituted benzoic acid and comprising a mixture of lactic acid and at least one other acid selected from formic acid, acetic acid and propionic acid said mixture being used as a medicament for animals.
A biocidal, antibiotic composition comprising (1) lactic acid or a derivative thereof capable of giving rise to lactic acid in vivo and (2) formic acid, acetic acid and/or propionic acid or a derivative of any capable of giving rise to formic acid, acetic acid and/or propionic acid respectively in vivo may be administered to the animals as a component of a conventional animal feed composition which is fed to animals. Thus, the biocidal composition comprising (1) and (2) may be suitably administered to the animals as a component of the animal feed or in their drinking water. Specific examples of derivatives of lactic acid which can give rise to lactic acid in vivo include salts of lactic acid such as eg the alkali metal-, the alkaline earth metal- and ammonium-lactates. The same applies to formic acid, acetic acid and propionic acid.
The amount of lactic acid and formic acid present in such a composition may vary within a wide range. Lactic acid and formic acid are usually sold commercially as aqueous solutions. For instance, lactic acid is sold as a 70% by weight solution whereas formic acid is sold as an 85% by weight aqueous solution. The weight ratio of lactic acid to formic acid in such a biocidal composition is suitably in the range from 99 : 1 to 1 : 99, preferably from 90 : 10 to 10 : 90 and more preferably from 80 : 20 to 20 : 80.
The amount of the biocidal composition comprising (1) and (2) administered to the animal is suitably such that it is sufficient to prevent/cure any infection in the animal in its capacity as a biocide. Such an amount is suitably in the range from 0.001 - 5% based on the total weight of each feed fed to the animal. This amount may, however, be higher if the function of the biocidal composition or a derivative thereof is not only to act as a biocide but also to control the pH of the animal excreta fed on such a diet in order to suppress the emission of ammonia from the excreta. Such higher amounts are suitably limited to a maximum of about 10% based on the total animal feed composition. The biocidal composition functions inter alia as an antibiotic, promotes growth, decreases feed conversion and improves digestibility of amino acids administered in animal feeds. A typical formulation for an animal feed composition is shown in the
Tables below in which all the amounts shown in % w/w were fed to pigs:
TABLE 1
Components of Starter Feed Control - Amount
Barley 31.5
Maize Gluten Feed 10.00
Wheat 10.00
Maize 18.75
Soybean oil meal 17.25
Tapioca 5.0
Wheat middlings 5.75
Animal fat 0.5
Limestone 0.80
Vitamin Premix 1.00
Salt 0.30
Monocalciumphosphate 0.40
The calculated chemical composition of this control feed in g/kg can be tabulated as follows:
TABLE 2
Component Amount (g/kg)
Crude Protein 160.61
Crude Fat 29.21
Crude Fibre 43.24
Water 145.35
Ash 47.01
Starch 404.32
Calcium 6.13
Phosphorus 5.94
Lysine 8.73
Methionine 3.29
Energy Value* 102.29
Sodium 1.42
Potassium 7.41
Chloride 2.63
Qlaqindox® - Antibiotic 0.05
'Energy value = 8.8 MJ net available energy for pigs for production and maintenance Thus, the biocidal, antibiotic composition of the present invention may be used in combination with additional ingredients selected from calcium carbonates, electrolytes such as eg ammonium chloride, proteins such as soya bean meal, wheat, starch, sunflower meal, corn, meat and bone meal, amino acids, animal fat, vitamins and trace minerals. In such a composition, the ratio of the electrolyte to the biocidal composition is suitably in the range from 0.5 : 1 to 5 : 1 w/w, preferably from 1.5 : 1 to 3 : 1 w/w.
The biocidal composition is particularly effective as a medicament for animals such as poultry, pigs or cattle, especially pigs. The present invention is further illustrated with reference to the following
Examples: EXAMPLES:
The following feed compositions (shown in Table 2 below) in which all the amounts shown in % by weight were fed to pigs. The amounts and concentrations
4
of formic acid, lactic acid and mixtures thereof shown are all in aqueous solution.
TABLE 3
Component Control* Ex I* Ex π Ex m*
DL-Methionine 0.020 0.020 0.020 0.020
TYLAN® - Tylosine 0.002 0 0 0
Fat 1.5 1.5 1.5 1.5
Vitamin/Minerals Premix 2.0 2.0 2.0 2.0
Molasses 2.7 2.7 2.7 2.7
Citrus pulp 5.0 5.0 5.0 5.0
Wheat 7.5 7.5 7.5 7.5
Maize gluten feed 16.05 16.05 16.05 16.05
Soybean oil meal 25.05 25.05 25.05 25.05
Tapioca 39.98 39.98 39.98 39.98
Lactic acid (70%) 0 1.0 0 0
50% Formic acid (85%) + 0 0 1.0 0 50% Lactic Acid (70%)
Formic acid (85%) 0 0 0 1.0
* - Comparative Feeds not according to the invention.
The calculated chemical composition (g/kg) of the Control feed used in the Control/Examples summarised in Table 3 above are shown in Table 4 below:
TABLE 4
Component Amount (g/kg)
Crude Protein 156.00
Crude fat 31.35
Crude fibre 49.97
Water 124.87
Ash 63.16
Starch 369.73
Calcium 5.66
Phosphorus 4.29
Lysine 8.85
Methionine 2.74
Energy value* 104.76
Sodium 1.74
Potassium 1 1.39
Chloride 2.49
Tylosine 20.00 mg
♦Energy value = 8.8 MJ net available energy for pigs for production and maintenance
In three pens pigs were fed with the control feed, and in the other three pens pigs were fed with the experimental feeds. The effect of the experimental feeds containing no acids (control), lactic acid alone (Ex I Feed), formic acid alone (Exp II Feed) and a mixture of lactic acid and formic acid (Ex II Feed, according to the present invention) on the performance of the pigs was compared. The performance of the above compositions on pigs fed therewith are summarised in Table 5 below:
TABLE 5
Control Ex I Feed* Ex π Feed E m Feed* Feed*
No. of Pigs 80 80 80 80
Initial Live weight (kg) 23.2 23.4 23.2 23.6
Final Live weight (kg) 110.2 111.8 112.8 109.6
Growth rate (g/day) 790 803 820 785
Feed intake (kg/day) 2.13 2.16 2.15 2.19
Feed conversion rate 2.70 2.69 2.62 2.67
No. of pigs dead 3 2 1 2
* Comparative Experiments not according to the invention.
The above results show that pigs fed with a diet comprising lactic acid/formic acid mixtures have a much lower feed conversion (calculated as a ratio of feed intake over growth per pig per day) than those fed on a diet which is:
(a) free of either (1) or (2) or
(b) contained either (1) or (2) alone.
These results also show that pigs fed on a feed comprising the acid mixture now claimed have are healthier and have a higher survival rate. These results also signify that pigs fed on a feed containing the acid mixture of the present invention is being used more efficiently.