Use of an animal feed additive in low-protein animal feeds for the breeding of pigs

Abstract

The present invention relates to the use of an animal feed additive for greatly protein-reduced animal feeds for the breeding of piglets and to corresponding low-protein animal feeds, wherein the animal feed additive comprises guanidinoacetic acid, lysine, methionine and threonine, and optionally tryptophan and / or valine, and the lysine content in the animal feed additive is chosen such that a ratio of lysine content in % by weight to crude protein content in % by weight in the range from 0.07 to 0.12 is established in the animal feed, and that the content of guanidinoacetic acid in the animal feed additive is chosen such that a weight ratio of guanidinoacetic acid to lysine in the range from 0.04 to 0.2 is established in the animal feed.

Description

[0001] Use of a feed additive in low-protein feed for pig rearing

[0002] Description:

[0003] The present invention relates to the use of a feed additive for highly protein-reduced feeds for the rearing of piglets and corresponding feeds.

[0004] The optimization of feed is an ongoing process that must be taken into account with many different aspects. Firstly, all of the nutrients an animal needs must be available in sufficient quantities in the feed. In addition to nutrient requirements, animal health is another factor that determines the optimal feed composition. Furthermore, the requirements of the feed also differ according to the different development phases of the animals. For example, an increased protein requirement is generally required when rearing young animals. In addition, numerous other factors must be taken into account, such as environmental aspects, regulations on fertilization and emissions during feed production. In order to meet these requirements, the protein content of the feed is generally reduced in order to lower the nitrogen and phosphorus content in the animal excrement, e.g. in liquid manure (see, for example, DLG Data Sheet 418, DLG eV 4.Revised edition, as of 10 / 2019).

[0005] To meet the requirements of modern feed, various feed additives are now used. First and foremost, deficiencies in the feed mixture are compensated for by the targeted addition of essential and growth-limiting nutrients. Examples include essential amino acids, calcium and magnesium, as well as trace elements and vitamins.

[0006] In contrast, the use of creatine or guanidinoacetic acid in pig farming has been little studied to date. For example, the use of guanidinoacetic acid has not yet been included in typical feed recommendations for pigs (see, for example, Bavarian State Office for Agriculture (LfL), Feed Calculation for Pigs, 26th edition, Dresden, Saxoprint GmbH, October 2021).

[0007] In contrast to creatine or creatine monohydrate, guanidinoacetic acid and its salts are significantly more stable in acidic aqueous solutions and are only converted into creatine under physiological conditions. Guanidinoacetic acid is only converted into creatine after absorption, primarily in the liver. Thus, unlike creatine, the majority of administered or fed compounds, guanidinoacetic acid and / or guanidinoacetic acid salts, are not degraded by instability reactions, e.g., in the stomach, but are actually available for the corresponding physiological metabolic reactions.

[0008] Sharma, Nishchal K. et al. (Poultry Science 101:101692, 2022) describe the use of guanidinoacetic acid as a substitute for the addition of arginine to low-protein poultry feeds. WO 2022 / 152583 A1 describes the use of a composition containing guanidinoacetic acid and glycine in fattening poultry with low-protein feeds. In pigs, the use of guanidinoacetic acid has previously been proposed to reduce stress in pigs during fattening (WO 2021 / 175677 A1).

[0009] The present invention therefore aims to provide a feed additive for piglet rearing that ensures adequate utilization of the proteins fed when feeding highly reduced-protein, amino acid-enriched feed. Furthermore, the feed additive is intended to reduce or even completely offset negative effects on piglet weight gain by reducing the crude protein content.

[0010] The object is achieved by the use of a feed additive comprising guanidinoacetic acid and lysine according to claim 1 and a feed according to independent claim 11. Preferred embodiments of the invention are specified in the subclaims, which can optionally be combined with one another.

[0011] Thus, according to a first embodiment, the use of a feed additive comprising guanidinoacetic acid (GAA) and lysine (Lys), methionine (Met), threonine (Thr) and optionally also tryptophan (Trp) and / or valine (Val) in a low-protein feed for piglets is the subject of the present invention, wherein the crude protein content in the low-protein feed is in the range from 14 to 18 wt.% based on the total weight of the low-protein feed and the content of metabolizable energy (ME) in the low-protein feed is in the range from 12.5 to 15.0 MJ ME per kg of the low-protein feed, and the lysine content in the feed additive is selected such that the ratio of lysine content in wt.% to crude protein content in wt.-% in the range from 0.07 to 0.12, whereby the lysine content and the crude protein content are related to the total weight of the feed and that the content of guanidinoacetic acid in the feed additive is selected so that in the low-protein feed a weight ratio of guanidinoacetic acid to lysine in the range from 0.04 to 0.2 is established, whereby the lysine content and the guanidinoacetic acid content are related to the total weight of the feed.

[0012] By using the wording “based on the total weight of the low-protein feed” or “based on the low-protein feed” as well as “based on the total weight of the feed” or “based on the feed”, the corresponding values ​​are based on a feed with 88% dry matter.

[0013] The term “feed additive” as used herein refers to a feed additive comprising guanidinoacetic acid and lysine, methionine and threonine, each as a free amino acid or as a salt thereof and optionally tryptophan and / or valine, each as a free amino acid or as a salt thereof.

[0014] The term "low-protein feed," as used herein, refers to the basic feed to which the feed additive according to the invention is added. The "low-protein feed" contains, in particular, a crude protein content of 14-18 wt.% and a metabolizable energy content in the range of 12.5 to 15.0 MJ ME per kg of the low-protein feed.

[0015] The term "feed," as used herein, refers to the combination of the feed additive according to the invention and the low-protein feed, and optionally other components. The resulting feed is, according to the invention, also low in protein and, to distinguish it from the component used as basic feed (which is referred to as low-protein feed), is also referred to as low-protein feed or reduced-protein feed.

[0016] The feed additive containing GAA, lysine, methionine and threonine and optionally tryptophan and valine is used in particular to improve weight gain during the rearing of piglets and thus to improve the utilization of the fed proteins by the piglets, particularly in comparison to a corresponding protein-reduced feed enriched only with amino acids.

[0017] The amino acid pattern required for an animal's growth is referred to as the "ideal protein." The more closely the dietary protein composition corresponds to this ideal protein, the more accurately the animal's needs are met while simultaneously avoiding oversupply. The ideal pattern of essential amino acids is usually expressed relative to lysine. Nevertheless, increasing the lysine-to-crude protein ratio (Lys / XP ratio) while reducing the crude protein content in the feed to below 18 wt.% and partially substituting the missing crude protein with amino acids from the group of lysine, methionine, threonine, tryptophan, and valine, corresponding to the ideal protein, surprisingly led to a significant deterioration in weight gain when piglets were reared on feed with this crude protein content. It appears that simply replacing the crude protein content with missing essential amino acids is not enough.

[0018] The feeding trials described below have shown that the administration of the described feed additive containing guanidinoacetic acid and the amino acids lysine, methionine, and threonine leads to improved utilization of the crude protein content and the additionally administered amino acids when rearing piglets on low-protein feeds. Using the feed additive can compensate for a reduction in piglet weight gain. This demonstrates that even very low-protein feeds can ensure adequate nutrition for the piglets, or even exceed their nutritional needs.

[0019] In the feeding trials presented here, all animals had, on average, a nearly identical starting weight. During the course of the feeding trial, it became clear that the animals fed the feed with an increased Lys / XP ratio without GAA but with additional lysine, methionine, threonine, tryptophan, and valine developed worse than the animals fed the same feed with a feed additive containing guanidinoacetic acid in combination with these amino acids. This is reflected in the weight development, particularly in the animals' daily gain. Increasing the Lys / XP ratio by reducing the crude protein content by 1.0% compared to a conventional low-protein feed led to a significant deterioration in the rearing of the animals. However, this could surprisingly be (over)compensated by using the described feed additive.By using a combination of GAA and the aforementioned amino acids, a very significant reduction in crude protein content, where the negative effects on the animals' weight gain could no longer be offset by the addition of essential amino acids, was more than offset. The improvement in performance, even beyond the level of the positive control, demonstrates that even a further increase in the Lys / XP ratio or a further reduction in crude protein content can be compensated for by the combined administration of GAA and lysine, methionine and threonine, and, if necessary, tryptophan and valine.

[0020] How this effect comes about is not entirely clear. The endogenous synthesis of the creatine precursor guanidinoacetic acid consumes the amino acids arginine (Arg) and glycine (Gly), which, in theory, are no longer required for GAA synthesis when GAA is fed directly and are available to the endogenous "protein pool" for other metabolic processes. Furthermore, creatine, which is formed from guanidinoacetic acid in the animal's body, is required for cellular energy metabolism. An improved supply of creatine, in conjunction with the provided amino acids, could promote the development of body structures in the animals. Furthermore, an improvement in protein or amino acid absorption through the intestinal wall during feed digestion by guanidinoacetic acid could promote more efficient utilization of very low-protein feed.

[0021] Low-protein feeds are characterized by their low or only slightly reduced energy content. The low-protein feeds used have a metabolizable energy (ME) content in the range of 12.5 to 15.0 MJ ME per kg of low-protein feed. The metabolizable energy content in low-protein feeds is preferably in the range of 13 to 14 MJ ME per kg of low-protein feed. Metabolizable energy is often also referred to as convertible energy.

[0022] The metabolizable energy content (ME) of the feed or feed is calculated using the following formula (Society for Nutritional Physiology, 2008: Prediction of metabolizable energy of compound feeds for pigs. Proceedings of the Society of Nutrition Physiology 17, 199-204): ME (MJ / kg) = 0.021503 (MJ / g) x XP (g / kg) + 0.032497 (MJ / g) x XL (g / kg) - 0.021071 (MJ / g) x crude fiber (g / kg) + 0.016309 (MJ / g) x starch (g / kg) + 0.014701 (MJ / g) x digestible residue (g / kg)

[0023] The formula therefore includes the analyzed contents of crude protein (XP), crude fat (XL), crude fiber, starch and the “digestible residue” (difference between the organic mass and the sum of XP, XL, crude fiber and starch, each in g / kg).

[0024] Commercially available feeds usually list the crude protein, crude fat, crude fiber, and starch content, allowing the metabolizable energy content to be calculated directly. Crude protein, crude fat, crude fiber, and starch content can also be determined using common VDLUFA methods (VDLUFA Methods Book III: 3rd Supplement 1993, Section 4.1.1 (Crude Protein Determination); 2nd Supplement 1988, Section 5.1.1 (Crude Fat Determination); 8th Supplement 2012, Section 7.2.1 (Starch Determination); 3rd Supplement 1993, Section 6.1.1 (Crude Fiber Determination)).

[0025] The (highly) protein-reduced or low-protein feeds for rearing piglets also have a crude protein content in the range of 14.0 to 18.0 wt.%, based on the total weight of the low-protein feed. Unless explicitly stated otherwise, the total weight of the feed or the total weight of the low-protein feed is to be understood as a dry matter of 88 wt.% (standardized). For the purposes of the present invention, low-protein feeds with a crude protein content in the range of 15 to 17 wt.% are preferably used. The upper limit can also be below 17 wt.%, for example, 16.8 wt.%. The crude protein content is usually stated for commercial feeds, but can also be calculated from the feed ingredients (VDLUFA Methods Book III, 5th Supplement 2004: Crude Protein, 4.1.1).When raising piglets, which have an increased protein requirement, the crude protein levels mentioned in the feeds used are very low. Negative effects on piglet development, especially on weight gain, cannot be compensated for by the addition of essential amino acids alone.

[0026] Based on this, it has been shown that this can be counteracted by using a feed additive that contains guanidinoacetic acid in addition to lysine, methionine, threonine, and possibly also tryptophan and valine. Lysine, methionine, and threonine, as amino acid building blocks, are partly contained in crude protein, but must also be added to the low-protein feed. They are therefore a mandatory component of the feed additive. If necessary, the additional addition of tryptophan and / or valine can also be beneficial in this regard.

[0027] According to the invention, the amino acids contained in the feed additive are added as free amino acids or in the form of a salt of these free amino acids, i.e., in particular, as free amino acids lysine, free amino acids methionine, free amino acids threonine, and optionally free amino acids tryptophan and / or free amino acids valine, or in the form of a salt of these amino acids. Unlike the amino acids lysine, threonine, tryptophan, and valine, methionine can also be utilized in the animal's metabolism in its D-form. Therefore, methionine can be used in both its D- and L-form in the feed additive. The other amino acids are preferably used in their L-form.

[0028] According to Lambert et al. J. Appl. Poult. Res. 31:100300, 2022, the lysine / crude protein ratio (Lys / XP ratio) is a measure of the nutrient density, particularly with regard to the content of (essential) amino acids, of a feed ration. The additional addition of lysine results in an increase in the Lys / XP ratio while simultaneously reducing the crude protein content. With regard to the present invention, it has proven advantageous in the rearing of piglets that the lysine content in the feed additive is selected such that a ratio of lysine content in wt.% to crude protein content in wt.% in the range of 0.07 to 0.12 is established in the feed, whereby the lysine content and the crude protein content are based on the total weight of the feed, standardized to 88 wt.% dry matter. Preferably, the lysine content in the feed additive is selected so that the Lys / XP ratio is in the range of 0.073 to 0.095.The Lys / XP ratio is particularly preferred in the range from 0.075 to 0.085.

[0029] To calculate the lysine / crude protein ratio (Lys / XP ratio), the total amount of lysine contained in the feed (comprising feed additive and low-protein feed) is used, i.e. the amount of free amino acid lysine added to the low-protein feed by means of the feed additive as well as the content of lysine amino acid building blocks in the low-protein feed.

[0030] The absolute amount of lysine in the feed is preferably in the range of 0.8 to 2.0 wt.% based on the total weight of the low-protein feed; the lysine content in the feed is particularly preferably in the range of 1.1 to 1.7 wt.%, particularly preferably in the range of 1.15 to 1.45 wt.%. However, the absolute lysine content in the feed may also deviate from this, provided the described Lys / XP ratio is maintained.

[0031] The methionine content in the feed additive is preferably selected so that a methionine to lysine ratio in the feed is in the range of 0.24 to 0.40, particularly preferably 0.31 to 0.37. The methionine+cysteine ​​to lysine ratio is often also specified with respect to methionine, which should preferably be between 0.45 and 0.90 and especially between 0.50 and 0.75.

[0032] The content of threonine in the feed additive is preferably selected so that a threonine to lysine ratio in the feed is in the range of 0.55 to 0.75, particularly preferably in the range of 0.58 to 0.70.

[0033] If the tryptophan and valine content in the crude protein of the low-protein feed is not already sufficient, these amino acids can also be added to the feed as an additive. The tryptophan content in the feed additive is preferably selected so that the tryptophan to lysine ratio in the feed is in the range of 0.14 to 0.24, particularly preferably 0.16 to 0.22. The valine content in the feed additive is preferably selected so that the valine to lysine ratio in the feed is in the range of 0.55 to 0.75, particularly preferably 0.58 to 0.70.

[0034] The stated amino acid ratios refer to the total weight of the respective amino acid contained in the feed, in particular to the sum of the free amino acid added in the feed additive and the corresponding amino acid components contained in the crude protein in the low-protein feed.

[0035] Furthermore, it is essential to the invention that the feed additive used comprises guanidinoacetic acid in a ratio to lysine in the range of 0.04 to 0.2. The GAA / Lys ratio is particularly preferably in the range of 0.05 to 0.15, especially preferably in the range of 0.6 to 0.10. Guanidinoacetic acid (syn.

[0036] Glycocyamine, N-guanylglycine, N-amidinoglycine; C3H7N3O2; CAS No. 352-97-6) is commercially available, just like the aforementioned amino acids.

[0037] Guanidinoacetic acid can be used as a free acid or in the form of a salt. The same applies to lysine, methionine, threonine, tryptophan, and valine, which can also be used as free amino acids or in the form of a salt. Therefore, the terms guanidinoacetic acid, lysine, methionine, threonine, tryptophan, and valine include the respective salts.

[0038] The preferred salt used is a salt selected from the group of alkali or alkaline earth metal salts. Particularly preferred guanidinoacetic acid salts are sodium guanidinoacetate, potassium guanidinoacetate, magnesium guanidinoacetate, or calcium guanidinoacetate.

[0039] However, the use of a feed additive containing guanidinoacetic acid as the free acid is particularly preferred, and a feed additive containing only the free acid and not its salts is particularly preferred.

[0040] The feed additive containing guanidinoacetic acid and lysine, methionine, and threonine, and optionally also tryptophan and valine, may contain other nutritionally active substances, for example, from the group of carbohydrates, fats, amino acids, vitamins, minerals, trace elements, methyl group donors, as well as derivatives of these substances and mixtures thereof. Useful ingredients are particularly selected from the group of vitamins. Preferred in this context are, for example, vitamin A, vitamin D3, vitamin E, nicotinic acid, nicotinamide, and choline. Other preferred ingredients are B vitamins, including thiamine, riboflavin, nicotinic acid, pantothenic acid, biotin, folic acid, cobalamin, and vitamin B1. These optional ingredients can be added to the feed additive or directly to the feed.

[0041] The amino acids lysine, methionine, threonine, tryptophan, and / or valine, as well as other optional ingredients of the feed additive, can be provided together with the guanidinoacetic acid as granules or in the form of a simple mixture. Direct addition of individual components of the feed additive to the feed is also conceivable. The latter is particularly preferred because it allows the Lys / XP, Met / Lys, Thr / Lys, Trp / Lys, and GAA / Lys ratios in the feed to be precisely adjusted independently of one another and taking into account the amounts of lysine, methionine, threonine, tryptophan, and valine already present in the crude protein of the low-protein feed. However, the use of a mixture of the feed additive ingredients is advantageous when a standardized low-protein feed is used.

[0042] Guanidinoacetic acid is preferably used in the form of granules containing at least one binder. Suitable binders include, in particular, nutritionally active substances that have a binding effect and enable good granulation of the composition, such as glycine, starch, or sugar. Other suitable binders include, for example, methylcellulose, ethylcellulose, carboxymethylcellulose, carboxyethylcellulose, carboxypropylcellulose, hydroxypropylmethylcellulose, hydroxymethylcellulose, microcrystalline cellulose, ethylmethylcellulose and other cellulose derivatives, hydroxypropyl starch, pregelatinized or modified starch, sugar syrup, dextrin, gelatin, propylvinyl alcohol, polyvinylpyrrolidone, xanthan gum, gum arabic, sodium chloride, sodium carbonate, sodium bicarbonate, and glycerin, as well as mixtures thereof.To improve the flowability of the granules, it may be advantageous for them to contain a flow aid, in particular a hydrophilic and / or hydrophobic silica and / or silicate-based additives and / or fatty acids and / or their salts, such as stearic acid or palmitic acid as well as their sodium, potassium and calcium salts.

[0043] The binder is preferably present in the granulated guanidinoacetic acid composition in amounts of 0.05 to 15 wt.%, in particular 0.1 to 1.5 wt.%. The particle size of suitable granules is preferably between 100 and 850 μm, with preferably less than 10 wt.% of the particles being below 100 μm and less than 10 wt.% of the particles being above 850 μm. Accordingly, the moldings preferably have a guanidinoacetic acid or guanidinoacetic acid salt content of 85 to 99.95 wt.%, in particular 95 to 98.5 wt.%. Flow agents and other additives can be present in the granules at up to 5 wt.%.

[0044] Guanidinoacetic acid is preferably used in an amount of at least 0.03 wt.% and particularly preferably at least 0.04 wt.%. The upper limit for the guanidinoacetic acid used is preferably 0.20 wt.%, further preferably at most 0.15 wt.%, particularly preferably at most 0.12 wt.%, and very particularly preferably at most 0.10 wt.% (based on the total weight of the feed standardized to 88% dry matter). According to a preferred embodiment, it is therefore provided that the guanidinoacetic acid is used in an amount of 0.03 to 0.20 wt.%, preferably from 0.04 to 0.15 wt.%, and particularly preferably from 0.04 to 0.10 wt.% (in each case based on the feed) in the feed additive used according to the invention, whereby the specified GAA / Lys ratio must be observed.

[0045] A particularly preferred embodiment of the present invention is thus the use of a feed additive comprising guanidinoacetic acid, lysine, methionine, threonine, tryptophan and valine, wherein the lysine content in the feed additive is selected such that the ratio of lysine content in wt.% to crude protein content in wt.% in the feed is in the range of 0.073 to 0.095, wherein the lysine content and the crude protein content are based on the total weight of the feed and the methionine content in the feed additive is selected such that the methionine to lysine ratio in the feed is in the range of 0.31 to 0.37 and the threonine content in the feed additive is selected such that the threonine to lysine ratio in the feed is in the range of 0.60 to 0.70 and the tryptophan content in the feed additive is selected such that the tryptophan to Lysine ratio in feed in the range of 0.18 to 0.22 and the valine content in the feed additive is selected such that a valine to lysine ratio in the feed is in the range of 0.60 to 0.70 and that the content of guanidinoacetic acid in the feed additive is selected such that a weight ratio of guanidinoacetic acid to lysine in the feed is in the range of 0.06 to 0.10, in a low-protein feed (also referred to herein as feed) for rearing piglets with a crude protein content in the range of 15 to 17 wt% based on the total weight of the feed and a metabolisable energy (ME) content in the range of 13 to 14 MJ ME per kg of the low-protein feed.

[0046] Two or more components of the feed additive can be incorporated into the feed as a premix during the production of the low-protein feed or individually.

[0047] The feed formed according to the invention by combining the feed additive and the low-protein feed is preferably itself a low-protein feed or a reduced-protein feed. The crude protein content of this feed or low-protein feed or reduced-protein feed is preferably in the range of 14 to 18 wt.%, more preferably in the range of 15 to 17 wt.%, and even more preferably in the range of 15 to 16.8 wt.%, based on the total weight of the feed.

[0048] Preferably, the low-protein feed into which the feed additive is incorporated should be provided ad libitum. In the context of the present invention, the term "ad libitum" refers to an amount of low-protein feed mixed with the feed additive that can be consumed freely and at will by the pigs. Thus, according to the present invention, the feed should preferably be provided "ad libitum," i.e., in excess for the animals' free use. The free use of the feed allows the animals to meet their nutritional needs.

[0049] The feed comprising the described feed additive is particularly suitable for rearing piglets from day 14 to 105, especially from day 21 to 91, and particularly preferably from day 28 to 70, after birth. During this rearing phase, the animals' protein requirements are particularly high, making the use of low-protein or reduced-protein feed particularly difficult without causing a loss of performance.

[0050] According to the present invention, a low-protein feed is preferably used which, with regard to the parameters of crude protein and energy content, is adjusted according to the ranges described herein. The low-protein feed can consist of a basic feed and further feed additives. It has been shown that particularly good results can be achieved if the feed comprises, as a basic feed, a) at least one vegetable component, in particular a cereal, a cereal flour, a cereal meal, a cereal extraction meal, a cereal semolina, a cereal bran or a cereal semolina bran, and b) a fat or oil of vegetable or animal origin. It is further preferred if the basic feed comprises at least one vegetable component selected from groups a1) to a7), in particular a cereal, a cereal flour, a cereal semolina, a cereal meal, a cereal extraction meal,a cereal bran or cereal semolina bran and / or an oilseed product and b) animal or vegetable fat and / or oil, where: a1) wheat, wheat flour, wheat semolina, wheat meal, wheat bran, wheat semolina bran made from these, which can also be used in a pre-gelatinised form, a2) barley, barley flour, barley meal, barley bran made from these, which can also be used in a pre-gelatinised form, a3) maize, maize flour, maize meal made from these, which can also be used in a pre-gelatinised form, a4) soy, soy meal, soy meal or a soy meal made from these, which can also be used in a pre-gelatinised form, a5) rapeseed, rapeseed meal, rapeseed meal or a rapeseed meal made from these, which can also be used in a pre-gelatinised form, and / or a6) sunflower, sunflower meal, sunflower meal or a sunflower meal made from these, which can also be used in a pre-gelatinised form, a7) feed components of animal origin with a high protein content.

[0051] The digested feed components a1) to a6) are generally heat- or acid-treated components. The proportion of digested components is generally less than 50% by weight based on the respective feed component a1) to a6). The proportion is particularly preferably between 5 and 20% by weight.

[0052] The feed components of animal origin (a7) include in particular components with a protein content of more than 15% by weight, e.g. selected from the group consisting of whey protein concentrate, whey fat concentrate, milk powder (including whole and skimmed milk powder), dried blood plasma, PAP (processed animal protein = animal meal (e.g. meat-bone meal, meat meal, blood meal) e.g. based on poultry).

[0053] The feed component (a7) is generally mixed in an amount of less than 25 wt.%, in particular between 2 and 15 wt.%, based on the total amount of feed (88% dry matter). In feeds used in the early rearing phase of piglets (10 days to 42 days after birth), the content of component a7) in the feed can be relatively high; component a7) is preferably in the range of 3 to 15 wt.%, particularly preferably 4 to 10 wt.%, based on the total weight of the feed. Feeds used later (from day 31 after birth or approximately 14 days after weaning, in particular up to day 105 after birth or approximately 90 after weaning) often contain a smaller amount of component a7), preferably up to 5 wt.%, in particular 0 to 3 wt.%, based on the total weight of the feed.After day 35 after birth of the animals, component a7) can be omitted from the feed, preferably from day 42 or later.

[0054] Other feed additives may be added to this basic feed. In particular, the low-protein feed may contain, in addition to the feed additive used according to the invention, other feed additives from the group of minerals, amino acids (with the exception of lysine, methionine, threonine, tryptophan, and valine), vitamins, trace elements, or mixtures thereof. Furthermore, creatine or methyl group donors, such as betaine and choline, may also be added to the feed, as already described above.

[0055] Many of these ingredients are added to the feed in the form of a mixture (premix), in particular to ensure that the animals receive an adequate supply of essential nutrients.

[0056] Preferred low-protein feedstuffs, which are particularly suitable for rearing piglets, comprise a) at least one carbohydrate-rich component selected from the group consisting of wheat, wheat meal, barley, barley meal, maize and maize meal; and b) a protein-rich component selected from the group consisting of oilseeds, such as soybean meal, soybean meal, rapeseed, rapeseed meal, rapeseed meal, sunflower, sunflower meal and sunflower meal, the proportions of which are, however, reduced in quantity so that a crude protein content of 18% by weight in the feedstuff is not exceeded; and c) optionally a low-energy component selected from the group consisting of brans, in particular wheat bran, wheat semolina bran, barley bran and maize bran; and d) a fat selected from the group consisting of animal or vegetable fats and oils, and e) optionally feed components of animal origin with a high protein content.

[0057] The proportion of carbohydrate-rich components in the preferred low-energy feeds is typically between 30 and 90 wt.%, particularly preferably in the range of 40 to 80 wt.%. The proportion of protein-rich components is preferably between 2 and 30 wt.%, particularly preferably in the range of 4 to 15 wt.%. The proportion of added fat is preferably between 0.5 and 10 wt.%, particularly preferably in the range of 1 to 8 wt.%, and most preferably between 3 and 6 wt.%, always based on the total weight of the low-protein feed. The weight proportions of the feed components must be weighted such that the protein content of the entire feed is in the range of 14 to 18 wt.%, based on the total weight of the feed.

[0058] It should be noted that the reduced metabolizable energy by reducing the weight proportion of protein-rich components is compensated by a corresponding weighting of carbohydrate- or fat-rich feed components, so that the low-protein feed has a metabolizable energy content of 12.5 to 15.0 MJ ME per kg of feed.

[0059] Furthermore, the low-protein feed may contain a small proportion of protein-rich components, which can be replaced, in particular, by cereals.

[0060] Low-protein feeds for piglets have proven advantageous which: a) contain crude protein in an amount of 14 to 18% by weight, in particular 15 to 17% by weight, and b) have a metabolisable energy content ME in the range of 12.5 to 15 MJ ME / kg feed, preferably 13 to 14 MJ ME / kg feed.

[0061] Examples of implementation:

[0062] In a feeding trial on rearing piglets, it was investigated whether the addition of guanidinoacetic acid (GAA) to the feed, in combination with the addition of lysine and other amino acids, could compensate for a 1.0% reduction in the crude protein content of the ration, with a concomitant increase in the lysine-to-crude protein ratio (Lys / XP ratio). An increase in the Lys / XP ratio was achieved in the present examples by keeping the calculated content of the amino acid lysine the same in all treatment groups, while reducing the crude protein content.

[0063] When Lys levels are referred to below, this includes the pattern of additionally administered amino acids, unless otherwise stated. The additionally administered amino acids methionine, threonine, tryptophan, and valine are used in the examples in a specific ratio to lysine. Therefore, if the Lys / XP ratio is increased by reducing the XP content of the ration, more synthetic amino acids are added to ensure the "ideal level" of essential amino acids in the feed.

[0064] Materials and methods:

[0065] The feeding trial was conducted by the Haus Düsse Agricultural Research and Training Center in Bad Sassendorf. In the trial, 178 newly weaned piglets (genetics: Topigs TN70 x PIC408) with an average age of 28 days and an average weight of 8.76 kg were fed one of three different feeding regimes. For each regime, 59 or 60 piglets were housed in six piglet rearing pens. A standard two-phase feeding system was used to ensure that the piglets' diets were fed as closely as possible to their needs (see Table 1). Both piglet rearing diets (FAZ) were fed for 21 days each. The animals were weighed individually at the time of entry, at the feed change, and at the end of the trial after 42 days to determine their weight gain. The feed intake was determined by measuring feed intake per pen.From these data, the daily gain, the daily feed intake per animal and the feed expenditure (kg feed per kg gain) per animal were calculated.

[0066] The feed concepts were based on the guidelines for very low nitrogen (N) and phosphorus (P) feeding defined in DLG Data Sheet 418 (DLG eV, 4th revised edition, as of October 2019). Table 1 shows the feed mix details. The feed of the positive control group was formulated such that the crude protein content (XP) of 17.3% was already slightly below the recommendations (DLG: 17.5%). The negative control feed was formulated with a 1% lower XP content compared to the positive control ration and differed from the GAA-containing feed only in the GAA supplement. All other crude nutrients, vitamins, macroelements, and trace elements were kept constant regardless of the feed concept. The feed composition of the positive control (PK) had a relatively low Lys / XP ratio, whereas the Lys / XP ratio of the negative control (NK) and GAA group (GAA) was higher due to the reduced crude protein content.

[0067] Table 1: Feed composition of the piglet rearing diets (FAZ) of the positive control (PK), negative control (NK) and GAA group (GAA)

[0068] MCP = monocalcium phosphate The amounts of L-Lys-HCl, DL-Met, L-Thr, L-Trp and L-Val given in Table 1 were added as free amino acids to the basic feed as a feed additive.

[0069] Table 2 shows the components of the rations. The reduction in crude protein content was achieved by reducing the incorporation rate of soybean meal and increasing the contents of grain and wheat bran. To maintain the levels of Lys and the other amino acids listed in Table 2, the incorporation rate of all supplemented amino acids in the negative control and GAA diets was increased (see Table 1). All other components were kept constant. This resulted in a Lys / XP ratio of 0.072 and 0.070 in the positive control diet, 0.076 in the FAZ 1 diet, and 0.075 in the FAZ 2 diet.

[0070] Table 2: Summary of crude nutrient and amino acid contents of the diets of the positive control (PK), negative control (NK) and GAA groups

[0071] The percentages for Lys, Met, Met+Lys, Val, Thr and Trp given in Table 2 each indicate the total content of the amino acid, i.e. the sum of the amino acid added as a feed additive and the amino acid content in the crude protein of the low-protein feed.

[0072] Results:

[0073] Table 3 presents the biological performance of the piglets over the observed rearing period of 6 weeks (41 days), with day 1 corresponding to the start of the feeding trial. The piglets had an average age of 28 days on day 1. Three piglets did not reach the end of the trial for reasons unrelated to the study and were excluded from the analysis.

[0074] Table 3: Summary of performance data of animals in the positive control (PK), negative control (NK) and GAA groups

[0075] PK NK GAA Total / Average

[0076] Number of animals day 41 n 59 59 57 175

[0077] Live mass

[0078] Day 1 kg 8.77 8.72 8.78 8.76

[0079] Day 21 kg 15.00 14.42 15.35 14.92

[0080] Day 41 kg 26.62 25.33 27.38 26.45

[0081] Daily weight gain

[0082] Day 1-21 g / day 297 T11 313 294

[0083] Day 22-41 g / day 567 533 588 563

[0084] 1st-41st day g / day 441 410 460 437 daily feed consumption

[0085] 1st-21st Day kg / d / animal 0.346 0.337 0.376 0.353

[0086] 22-41. Day kg / d / animal 0.930 0.886 0.974 0.930

[0087] 1st-41st Day kg / d / animal 0.641 0.614 0.676 0.644

[0088] Feed expenditure

[0089] 1st-21st Day kg / kg 1.17 1.26 1.21 1.21

[0090] 22-41. Day kg / kg 1.64 1.68 1.65 1.66

[0091] 1st-41st Day kg / kg 1.47 1.54 1.50 1.51

[0092] All observed animals had on average an almost identical starting weight, but already at the time of the feed change (day 21) and especially at the end of the experiment, it was clear that the animals that were given the feed with an increased Lys / XP ratio without GAA grew less well than the animals that were given the same feed with added GAA (final weight: positive control: 26.62 kg, negative control: 25.33 kg, GAA: 27.38 kg).

[0093] This was reflected in the daily weight gain calculated from weight development. In each rearing phase, the animals in the GAA group showed the highest daily weight gain (over the entire experimental period: positive control: 441 g / day, negative control: 410 g / day, GAA: 460 g / day).

[0094] The average feed consumption of the three treatment groups followed a similar relationship, with the negative control animals eating the least feed and the GAA group eating the most (positive control: 0.641 kg / day, negative control: 0.614 kg / day, GAA: 0.676 kg / day).

[0095] Nevertheless, the feed consumption, i.e., the amount of feed required for one kg of gain, was lower in the GAA group than in the negative control. Over the entire experimental period, the positive control animals required 1.47 kg of feed per kg of gain, the negative control animals 1.54 kg / kg, and the GAA group piglets 1.50 kg / kg. Thus, the GAA group was closer to the positive control than to the negative control group.

[0096] An increase in the Lys / XP ratio by reducing the crude protein content by 1.0% compared to the positive control led to a significant deterioration in performance, which is evident when comparing the positive and negative control groups. Surprisingly, the addition of GAA to the feed of the negative control group was able to (over)compensate for this effect, whereby the GAA piglets showed the highest weight gains over the 42-day piglet rearing period and also performed better in feed utilization than the animals in the negative control. With a GAA / Lys ratio of approximately 0.075, a very significant reduction in crude protein content, at which the negative effects on the animals' weight gain could no longer be compensated for by the addition of essential amino acids, could be compensated for. The improvement in performance even beyond the level of the positive control shows that even a further increase in the Lys / XP ratio ora further reduction in crude protein content can be compensated by GAA administration.

Claims

Patent claims:

1. Use of a feed additive comprising guanidinoacetic acid and lysine, methionine and threonine and optionally tryptophan and / or valine in a low-protein feed for piglets, wherein the crude protein content in the low-protein feed is in the range from 14 to 18 wt.% based on the total weight of the low-protein feed and the content of metabolisable energy (ME) is in the range from 12.5 to 15.0 MJ ME per kg of the low-protein feed, characterized in that the lysine content in the feed additive is selected such that the ratio of lysine content in wt.% to crude protein content in wt.-% in the range from 0.07 to 0.12, whereby the lysine content and the crude protein content are related to the total weight of the feed, and that the content of guanidinoacetic acid in the feed additive is selected so that a weight ratio of guanidinoacetic acid to lysine in the range from 0.04 to 0.2 is established in the feed, whereby the lysine content and the guanidinoacetic acid content are related to the total weight of the feed.

2. Use according to claim 1, characterized in that the low-protein feed has a metabolizable energy in the range of 13.0 to 14.5 MJ ME / kg of low-protein feed.

3. Use according to one of the preceding claims, characterized in that the low-protein feed has a crude protein content in the range of 15 to 17 wt.% based on the total weight of the low-protein feed.

4. Use according to one of the preceding claims, characterized in that the lysine content in the feed additive is selected such that a ratio of lysine content in wt.% to metabolizable energy (ME) in MJ in the range of 0.085 to 0.120 is established in the feed.

5. Use according to one of the preceding claims, characterized in that the ratio of lysine content to crude protein content in wt.% based on the total weight of the feed is in the range from 0.073 to 0.095, particularly preferably in the range from 0.075 to 0.

085.

6. Use according to one of the preceding claims, characterized in that the content of methionine in the feed additive is selected such that a methionine to lysine ratio in the feed is in the range from 0.28 to 0.40 and that the content of threonine in the feed additive is selected such that a threonine to lysine ratio in the feed is in the range from 0.55 to 0.

75.

7. Use according to one of the preceding claims, characterized in that tryptophan is present in the feed in a tryptophan to lysine ratio in the range of 0.16 to 0.24 and that the content of valine in the feed is in a valine to lysine ratio in the range of 0.55 to 0.

75.

8. Use according to one of the preceding claims, characterized in that the feed additive comprises tryptophan and valine, wherein the content of tryptophan in the feed additive is selected such that the tryptophan to lysine ratio in the feed is in the range from 0.16 to 0.24 and that the content of valine in the feed additive is selected such that the valine to lysine ratio in the feed is in the range from 0.55 to 0.

75.

9. Use according to one of the preceding claims, characterized in that the feed additive contains i) guanidinoacetic acid as a free acid or in the form of a salt of this acid and / or ii) lysine as a free acid or in the form of a salt of this acid.

10. Use of a feed additive according to any one of the preceding claims for rearing piglets in a period from day 14 to 105 after the birth of the piglets.

11. Low-protein feed for piglets with a metabolizable energy in the range of 12.5 to 15.0 MJ metabolizable energy (ME) / kg feed containing 14 to 18 wt% crude protein based on the total weight of the low-protein feed, additionally lysine, so that the low-protein feed has a ratio of lysine content in wt% to crude protein content in wt% in the range of 0.07 to 0.12, wherein the lysine content and the crude protein content are based on the total weight of the low-protein feed and additionally methionine and threonine and Guanidinoacetic acid in an amount selected so that the low-protein feed has a weight ratio of guanidinoacetic acid to lysine in the range of 0.04 to 0.

2.

12. Use of a low-protein feed according to claim 11 for rearing piglets, in particular for feeding the piglets from day 14 to 105 after their birth.

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