BACKGROUND OF THE INVENTION Usually, most feeds for animal consumption, both in industrial fattening or production and for pet animals (pet foods), contain growth promoters, generally drugs, such as antibiotics, anti-coccidiostatics and others.

The objective in use of said products is to maintain an optimum state of health in the animals, in addition to optimizing their growth, production of meat, eggs, etc.

For this reason, it is common practice to supply animal feeds to which antibiotics, anti-coccidiostatics, etc. , have been added for fattening of the animals, while also preventing the possibility of the animal falling ill (illness being highly probable since the fact that they live in groups makes it easier for infection to spread).

Lamb might be mentioned as an example, that it is characterized by being an animal which presents major health problems during its indoor fattening, for which reason it always needs to eat feed which contains growth stimulants, anti-coccidiostatics or antibiotics. This fact means that the absence of antibiotics and other substances during the fattening periods gives rise to health problems

in the animal, leading to weight loss, growth problems, etc. , which often shows itself in major economic losses for stockbreeders.

The use of feeds containing such products nevertheless involves the following problems: (a) The animals receive constant medication included in their food, which is always harmful in itself and because, in the long term, the animals end up developing resistance to the drugs supplied to them, which are then insufficiently effective against microbes, viruses or bacteria.

(b) The possibility that residues of the medication may remain in the meat of these animals, despite periods of suppression being applied, during which such drugs or additives are no longer supplied before the animals are slaughtered.

The objective of this invention is to solve the disadvantages presented by the use of products such as antibiotics, growth stimulants and anti-coccidiostatics for the fattening of animals.

DESCRIPTION OF THE INVENTION This invention refers to the use of an oil which includes at least one omega-3 fatty acid for non-human animal consumption as a substitute of an antibiotic.

In an embodiment of the present invention, said oil acts as an antibacterial agent.

In another embodiment of the present invention said oil acts as a growth stimulant agent.

In yet another embodiment of the present invention, said oil acts as an anti-coccidiostatic agent.

One advantageous aspect of this invention is that the oils which include omega-3 fatty acids are natural products, so that their addition to the feed achieves a high-quality meat product and does not present the characteristic residues produced when drugs (antibiotic, growth-stimulating factors, etc. ) are used.

Another advantageous aspect lies in the fact that said acids act to reinforce the immune system, so that as they are not specific to a particular infectious agent (such as bacteria, etc. ) the development of resistance is hindered.

In this invention, the term"oil"refers to any oily composition in any of its physical forms. Thus, for example, oils such as tuna oil (liquid), whale oil (solid appearance), etc. , can be used.

In this invention, the term"animal"refers to any animal, and therefore includes both pets and animals which are fed so that all their derivatives are destined to human consumption. Examples of these last animals include rabbits, partridges, sheep, etc.

In a preferred embodiment of this invention, the acid used can be of animal origin, such as from tuna, whale, etc.

In another preferred embodiment of this invention, the oil and/or fat can be of plant origin, such as that from algae.

Optionally, said oils have a high content in omega-3 fatty acids as a result of their treatment by a procedure of concentration.

In this invention, oils which have been submitted to a procedure of concentration of omega-3 fatty acids are called"oils enriched in omega-3 fatty acids".

Preferably, the concentration of omega-3 fatty acids in the oil ranges from 10-99%, though more preferably between 50 and 99%.

Said omega-3 fatty acids can likewise be found chemically modified, as for example in the form of esters of methyl or ethyl or glycerides, among others.

Advantageously, the object of this invention is an alternative to the products used (drugs) in the state of the art for the fattening of animals, such as antibiotics, growth stimulants or anti-coccidiostatics.

In a preferred embodiment, the oil used includes docosahexaenoic acid (Dha).

In another preferred embodiment, the oil used includes eicosapentanoic acid (Epa).

In yet another preferred embodiment, the oil of this invention includes a mixture of docosahexaenoic acid and eicosapentanoic acid.

As mentioned above, the omega-3 fatty acids used according to this invention, and especially Dha and Epa, have a high capacity as stimulants of the immune system of animals, permitting fattening of animals without the need to use antibiotics and the like.

Another advantageous aspect of this invention is that a meat highly enriched in omega-3 fatty acids is obtained, with the beneficial consequences which said acids involve for the health of people who consume it (such as a reduction of triglycerides in the blood, reduced risk of atherosclerosis, reduction of cardiac problems, etc.).

Included below by way of illustrative but non- restrictive example are examples of embodiment of this invention.

EXAMPLES Example 1: Use of omega-3 fatty acids for fattening lambs The starting point in this example was 25 batches of 50 animals each, testing different oils with different omega-3 fatty acid compositions. For this purpose different compositions were supplied at different times over the course of the trial, in order to find which of the fatty acids supplied were the most effective.

Another aspect to be determined in this example was to assess the final Dha in the flesh of the animal for human consumption and to evaluate how to avoid the potential undesired effects that might arise from use of an oil with a high index of fish by-products in animal

feed, such as the fish flavour in the meat products from animals fed with fish meals or oils.

The following were the oils used: Tuna oil: oil with a high Dha content (18% Dha/7% Epa).

Fish oil: 18% Epa and 12% Dha.

Oil enriched with a minimum Dha content of 50%.

Oil enriched with a minimum Epa content of 50%.

Tests carried out Merino-type lambs were used, fed with tuna oil (to enrich the feed with Dha) and 18/12 fish oil (18% Epa, 12% Dha) to enrich the feed with Epa. Oils with a high Dha concentration (Dha 50%) were also used for the high enrichments and to study the flavour problems mentioned above.

Early ages: the mothers were fed with Dha by adding tuna oil with a composition of 18% Dha and 6% Epa to the feed, since the young lambs during the first weeks of life would take small quantities and the foundation of their diet was maternal milk.

The mothers were initially given daily a feed which included 50 grams of Dha, being observed, within a short time interval, positive effects in the animals, as there were fewer cases of illness and the animals grew normally. The dose of Dha was gradually increased, in such a way that clear beneficial effects began to be observed from 0.200 grams of Dha a day and upwards (in speaking of doses, these are always taken to mean over total Dha or Epa supplied).

From 10 kg live weight: the lambs began to ingest animal feed regularly, so that the omega-3 fatty acid could be introduced directly into the feed they would consume. Various types of dosages were tried at this age, with beneficial effects being found from a consumption of 50 milligrams a day, whether of Dha or Epa independently, although the best results were obtained for doses equal to or higher than 500 milligrams animal/day. In particular, doses of Dha ranging between 500 milligrams/day and 1 gram/day were administered. The administration of higher doses did not result in a significant increase in the benefits.

During this period 600 lambs were fed, supplying them with a feed at the aforementioned dose of Dha and Epa.

The results obtained are shown in Table I. This table shows the results obtained with a group of lambs fed with a commercial feed containing 0.5 g of anti- coccidiostatic, in addition to antibiotics and stimulant factors and the results obtained with a group of lambs fed with a feed to which 0.5 g of Dha had been added.

Table I. Comparative results for lambs of 10-18 kg in weight fed with 0.5 g of an anti-coccidiostatic or with Dha 10-18 kg/0.5 g per day With Coccid. With Dha Weight at start 10. 20 9. 90 Days'feeding 25 25 Final weight 18. 30 18. 50 Kg of feed 21. 20 22. 70 Kg of weight gained 8. 10 8. 60 No. of batches 0. 80% 0. 90% Kg of feed/kg of meat 2. 62 2. 64

As shown, the use of Dha permits the fattening of animals, proving equal to or even more effective than commercial feeds containing a mixture of drugs (anti- coccidiostatics, growth stimulants, etc. ), with the consequent advantages possessed by the use of the omega-3 fatty acids.

From 18 kg live weight: from this age, although beneficial effects are found from 100 milligrams a day of either Dha or Epa, the doses at which most benefit is found are of about 2 grams of Dha daily. Feed containing Dha was given to 1, 237 lambs. In parallel to this group, 1,231 lambs wee fattened with feed containing a mixture of anti-coccidiostatic, antibiotics and growth stimulants, while a further 50 lambs were fattened with a feed containing no drug or omega-3 fatty acid.

The results are shown in Table II, which provides a comparison of the results obtained when the animals were given a dose of 1.5 to 2 grams a day, whether of a drug or Dha in the feed, with those obtained when the animals were given a feed to which none of the aforesaid substances had been added.

Table II. Comparative results for lambs of 18-25 kg in weight fed with a feed containing, among other drugs, an anti- coccidiostatic (With Coccid.), or Dha (With Dha) or containing none of those substances (Without Coccid.) 18-25 kg/1.5 to With Coccid. With Dha Without 2 g per day Coccid. Weight at start 18. 70 18. 10 18. 50 Days'feeding 20 20 20 Final weight 25. 00 25. 30 22. 00 Kg of feed 24. 70 25. 35 20. 10 Kg of weight 6.30 7.20 3.50 gained No. of batches 0. 40% 0. 20% 3. 80% Kg of feed/kg of 3.92 3.52 5.74 meat

As in the previous case, it was observed that the omega-3 fatty acid Dha added in the same quantity as the anti-coccidiostatic results in fattening of the lambs of the same order as that achieved with a commercial feed containing the mixture of drugs, but with the attendant benefits involved in use of Dha instead of any drug, as mentioned above.

Table III. Sum of the results obtained en Table I and Table II 10-25 kg With Coccid. With Dha Weight at start 10. 20 9. 90 Days'feeding 45 45 Final weight 25. 00 25. 30 Kg of feed 45. 90 48. 05 Kg of weight gained 14. 80 15. 40 No. of batches 1. 20% 1.10% Kg of feed/kg of meat 3. 10 3. 12

In the light of the results obtained it is clear that the omega-3 fatty acids permit the fattening of lambs with the same advantages as the stimulants, anti- coccidiostatics and antibiotics usually used to improve growth and meat production in the animals, but with the advantage that the meat is of better quality since it does not contain residues of antibiotics, etc. , and is, furthermore, enriched with omega-3 fatty acids, which have beneficial properties for health.

Moreover, as mentioned, the main disadvantage in the use of oils rich in Dha for the fattening of animals is the fish flavour it usually leaves when said oil is used in large doses. This flavour can be so intense as to prevent the sale of such meat. However, the conditions for preventing or overcoming this problem have been optimized as set out below.

(a) By implementing a period of withdrawal of the oil containing the omega-3 fatty acid prior to slaughter, thus reducing this problem significantly or even, depending on the doses used and the length of the period, solving the problem.

(b) By using oils enriched up to 70% (in Dha or Epa), which can reduce up to three times the amount of oil that must be added to the feed, so that such oils practically eliminate the problem of the flavour in the meat.

Finally, we might note the advantages presented by meat or meat by-products from lamb obtained as described above: (i) Meat that is totally free from residues of antibiotics, stimulants or anti-coccidiostatic, since these were not used during the fattening.

(ii) Meat highly enriched in omega-3 fatty acids, with the attendant health benefits for those consuming it.

(iii) The use of oils with a high concentration of omega-3 fatty acids free from flavours and smells allows the composition of the fatty acids of the meat to be varied. Indeed, with this technique it proved possible to eliminate the typical wool flavour usually possessed by meats and meat by-products of lamb over 25 kg live weight, making the meat milder and suited to the taste of consumers.

Example 2: use of omega-3 fatty acids in other animals In addition to the trials carried out with lambs, trials were carried out with the following animals.

Chickens Hens Rabbits Pigs Partridge Calves

The same effects and benefits as found with lambs were found in all cases, with particularly significant results with sucking pigs and quail, chickens and rabbits.

Described below are the results obtained in the trial conducted with rabbits.

Trials with rabbits Two batches of 1,000 rabbits each were prepared, one being fed with feeds to which oils rich in omega-3 fatty acids had been added, so that the amount of Dha ingested in the feed per rabbit over the twenty days the fattening lasted was 3.5 grams.

The second batch of rabbits was administered a commercial feed containing, among other substances, an anti-coccidiostatic.

Both batches had an initial weight of around 650 g live weight.

The results obtained are shown in Table IV. This table shows a comparison of the effect of a feed to which an anti-coccidiostatic had been added with a feed to which Dha had been added.

Table IV With Coccid. With Dha Weight at start in g 700 725 Days'feeding 24 24 Final weight in g 2, 200 2, 150 Kg of feed 3. 92 4. 01 G of weight gained 1, 400 1, 425 Kg of feed/kg of 2.80 2.81 meat Batches 3. 00% 3. 05%

As may be seen from the final results obtained from trials with both feeds, there are practically no significant differences in weight gain, so the omega-3 fatty acids can be used for fattening with the above-mentioned advantages in relation to the drugs used for the same purpose (such as antibiotics, etc.).