USE OF A FEED ADDITIVE IN LOW-PROTEIN FEED FOR POULTRY

Description

[0001] The present invention relates to the use of a composition containing guanidinoacetic acid and glycine in the fattening of poultry with a low-protein feed.

[0002] The fixation of atmospheric nitrogen can only occur by plants, not by animals. Livestock are kept for meat production, i.e., for the production of animal proteins. Livestock can only produce their own proteins from the proteins or amino acids they are fed. In livestock, these amino acids typically come from plant feed and, to a lesser extent (e.g., fish meal), from animal feed.

[0003] The goal of meat production is the optimal provision of all necessary nutrients. The optimal composition of feed can be determined based on various criteria. These can include the animal's needs, animal welfare, cost considerations, or environmental aspects. A recommendation for feed composition for various animals is published, for example, by the National Research Council US (NRC). An overview of the historical development [Applegate, TJ, Angel, CR (2014) J. Appl. Poult. Res. 23: 567-575] of feed compositions shows the various reasons why feed recommendations have changed over time.

[0004] In addition, new factors have emerged in recent years that were previously ignored in feed formulation. For example, feeding high-protein feed is harmful from an environmental perspective. The animals' feces contain more nitrogen, which is broken down into nitrates that are harmful to water. Furthermore, increased ammonia emissions are occurring in the barn air. In this context, the production of plant proteins and the associated increased use of nitrogen fertilizers such as urea should also be mentioned. The environmental benefits of a low-protein diet for broiler chickens have been analyzed and described [Aletor VA, Hamid II, Niess E., Pfeffer E. (2000) Journal of Science of Food and Agriculture 80: 547-554].

[0005] Lower costs have been cited as another advantage of a low-protein diet [Aftab U., Ashraf M., Jiang Z., (2006) World's Poultry Science Journal, 62: 688-701]. A feed with a high plant protein content is generally more expensive than a feed with a low plant protein content of the same energy content. A health benefit from a low-protein diet is also evident. The growth of undesirable or pathogenic bacteria is reduced with a low-protein diet [Namroud NF, Shivazad M., Zaghari M., (2008) Poultry Science, 87: 2250-2258].

[0006] However, a low-protein diet can also have disadvantages. A lack of protein can lead to important bodily functions not being carried out at all or not being carried out sufficiently. Various possible causes of adverse effects of a low-protein diet in broiler chickens and the consequences of a deficiency in selected proteins have been investigated [Khajali F., Widemann RF, (2010) World's Poultry Science, 66: 751-766]. In-depth studies showed that the effects in all animals included protein deficiency dystrophy, edema formation, and a reduced growth rate. Clinically, protein deficiency is associated with reduced serum albumin levels, low hemoglobin levels, and reduced extracellular potassium. Physical manifestations include frequent infections, diarrhea, hypothermia, and cachexia. In broiler chickens, the occurrence of pulmonary hypertension has been described as a result of protein malnutrition [Behrooj N., Khajali F., Hassanpour H., (2012) British Poultry Science, 53: 658-664].

[0007] When feeding farm animals, it is therefore advisable to provide a balanced protein diet that is, on the one hand, as low in protein as possible in order to reap the benefits of a low-protein diet, but, on the other hand, sufficiently rich in protein to avoid deficiency symptoms. In practice, it is difficult or even impossible to achieve the optimal composition in order to reap the benefits of a low-protein diet without any disadvantages due to natural fluctuations in the feed offered and the different needs of each individual animal. In practice, it has been observed that the average weight of animals on a low-protein diet is lower than on a normal diet [Sharifi MR, Khajali F., Jonaghani BA, Pour HH, Safarpour A., (2016) Research on Animal Production, 14: 51].

[0008] A different standard deviation and variance of animals or animal parts, or a deviation in the slaughter rate, can also occur with a change in feeding. The so-called uniformity of the flock depends on many factors. Breeders issue recommendations for this [Ross, Broiler Management Handbook 2018, p. 109 ff.]. Attempts have been made to circumvent these disadvantages by adding essential amino acids [Jiang Q., Waldroup P., Fritts C., (2005), Int. J. Poult. Sci. 4:115-122]. However, the disadvantage of the low-protein diet relative to the standard diet could not be compensated for by adding individual essential amino acids, nor by supplementing with a combination of essential amino acids [Si J., Fritts C., Burnham D., PW Waldroup, (2004) Int. J. Poult. Sci. 3: 46-50].

[0009] Further attempts to circumvent these disadvantages were made by adding non-essential amino acids. Supplementation with proline, glutamic acid, and aspartic acid did not produce the desired effect [Corzo A., Fritts C., Kidd M., (2005) Anim. Feed Sci. Tech. 118:319-327]. Positive effects were observed when glycine was added to a low-protein diet containing 16% crude protein [Dean D., Bidner T., Southern L. (2006) Poult. Sci. 85:288-296; Awad E., Zulkifli I., (2015) Poult. Sci. 94:2772-2777]. These effects can be explained by the fact that glycine is found primarily in the keratin of feathers, and glycine supplementation primarily prevents feather loss.

[0010] A. Abudabos et al., Italian Journal of Animal Science, Vol. 13 (2014), pages 548-556, describes the relationship between guanidinoacetic acid and metabolizable energy in feed on chicken performance. Guanidinoacetic acid is added to various feeds. In summary, there is currently no economical method to fully compensate for the disadvantages of a low-protein diet for poultry.

[0011] The present invention is therefore based on the object of providing a feed additive for fattening poultry which, when fed low-protein feed, significantly increases the weight of the animals at the end of fattening compared to feeding with a low-protein feed alone and, if possible, achieves the weight achieved when fed with a balanced, high-protein diet. The present invention is further based on the object of providing a feed additive for fattening poultry which, when fed low-protein feed, significantly improves the uniformity of the weight of the animals at the end of fattening compared to feeding with a low-protein feed alone and, if possible, achieves the uniformity achieved when fed with a balanced, high-protein diet. One object of the feed additive is therefore to reduce the standard deviation from the mean slaughter weight at the end of fattening.

[0012] This object is achieved by a use according to claim 1. Preferred embodiments of the invention are specified in the subclaims, which can optionally be combined with one another.

[0013] Thus, according to a first embodiment, the present invention relates to the use of i) a composition containing guanidinoacetic acid and glycine, wherein the composition contains the glycine as the free acid or in the form of a salt of this acid; and ii) a low-protein feed for poultry having a crude protein content in the range of 14.0 to 18.5 wt.% (based on the total weight of the feed) during fattening from the 11th to 39th day of life of the poultry, for increasing the fattening performance of the poultry and / or for increasing the slaughter weight of the poultry and / or for improving the uniformity of the slaughter weight of the poultry, wherein the guanidinoacetic acid is used in an amount of 0.01 to 0.20 wt.% based on the low-protein feed and wherein the glycine is used in an amount of 0.01 to 0.20 wt.% based on the low-protein feed.

[0014] Essential to the invention, a composition containing guanidinoacetic acid and glycine and a low-protein feed are used in the fattening of poultry. According to the present invention, a low-protein feed is understood to mean a feed with a crude protein content in the range of 14.0 to 18.5 wt.% (based on the feed). The crude protein content according to the present invention was determined via the nitrogen content according to the Kjeldahl method using the Büchi AutoKjeldahl Unit K-370. Multiplying the nitrogen content by 6.25 yields the crude protein content. This is based on the assumption that an average protein contains 16 wt.% nitrogen.

[0015] According to a preferred use, it is provided that the low-protein feed for the poultry has a crude protein content in the range of 14.0 to 18.0 wt.%, more preferably in the range of 15.0 to 18.0 wt.%, even more preferably in the range of 16.0 to 18.0 wt.% and particularly preferably in the range of 16.5 to 18.0 wt.% and very particularly preferably 17.5 wt.% (based on the total weight of the feed).

[0016] Another essential aspect of the invention is that the composition and the low-protein feed are used during fattening from the 11th to the 39th day of the poultry's life (hereinafter also referred to as the fattening phase), and thus outside the first growth phase of the animals (hereinafter also referred to as the starter phase), which comprises the first to the 10th day of the poultry's life. During the fattening phase, a significantly larger amount of feed is consumed, both absolutely and per day, compared to the starter phase, and a greater daily weight gain is achieved. Therefore, it is particularly economically interesting to use a low-protein feed during this fattening phase and not to interfere with the recommended diet during the sensitive starter phase from day 1 to day 10. The feed intake from the 40th day onwards is also advantageous.The phase beginning on the 1st day is not covered by the present invention, since with increasing age and weight the protein requirement in the diet decreases and, moreover, in modern animal fattening there is only in a few cases an interest in heavier and thus older animals.

[0017] According to the invention, the composition containing guanidinoacetic acid and glycine and the low-protein feed for poultry are used on at least one, more preferably at least 5, even more preferably at least 10, in particular at least 20 and most preferably on all days from the 11th to the 39th day of the poultry's life.

[0018] According to a particularly preferred embodiment, the composition consists of guanidinoacetic acid and glycine.

[0019] Guanidinoacetic acid (syn. glycocyamine, N-guanylglycine, N-amidinoglycine; C 3 H 7 N 3 O 2 ; CAS No. 352-97-6) has been available on the market as a feed additive for some time and is approved for use in poultry fattening. Numerous studies have shown, among other things, that guanidinoacetic acid improves feed intake and increases fattening performance.

[0020] Glycine (syn. Glycoll, aminoacetic acid, aminoethanoic acid; C 2 H 5 NO 2 , CAS No. 56-40-6) is approved in the EU as food additive E640 without any quantity restrictions and has also been available on the market as a feed additive for some time. Studies on chickens [Corzo A., Kidd, MT (2004) Poult. Sci. 83(8), 1382-4] have shown that glycine is a limiting nutrient, even though it is also produced by the animal itself.

[0021] In contrast to creatine, 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 guanidinoacetic acid is not broken down by instability reactions, e.g., in the stomach, and excreted before absorption, but is actually available for the corresponding physiological metabolic reactions.

[0022] Surprisingly, feeding trials have now shown that the administration of a composition containing guanidinoacetic acid and glycine leads to the desired benefit, namely when feeding low-protein feed to increase the fattening performance and the fattening weight of the animals at the end of fattening and to improve the uniformity of the animals' weight.

[0023] Chickens fed a low-protein diet enriched with guanidinoacetic acid and glycine achieved better growth and higher slaughter weight compared to the control group, which received the same low-protein diet but without the addition of guanidinoacetic acid and glycine. This effect was observed both in comparison to diets enriched with glycine alone and in comparison to diets enriched with guanidinoacetic acid alone, with a completely surprising synergistic effect of the two individual substances being observed.

[0024] In the animal body, the non-essential amino acid glycine can be formed from 3-phosphoglycerate, a glycolysis intermediate, via serine as an intermediate step. In a further step, guanidinoacetic acid is formed from glycine and L-arginine. Guanidinoacetic acid is further methylated to creatine. Creatine plays an important role in cellular energy production. Since guanidinoacetic acid is formed from glycine, it was not expected that a positive synergistic effect would occur when both components are administered. Without being bound by theory, it is therefore assumed that the simultaneous administration of guanidinoacetic acid and glycine has positive effects that are not linked to energy metabolism.

[0025] The administration of the composition according to the invention containing guanidinoacetic acid and glycine can be realized in different ways. For example, the composition can be used as a solid preparation mixed with the low-protein feed or dissolved in water as a drinking solution. Thus, a preferred use is also the subject of the invention in which the composition a) is provided as a solid preparation mixed with the low-protein feed for the poultry or b) is provided as a drinking solution for the poultry separate from the low-protein feed. In any case, the drinking solution, the low-protein feed, or the low-protein feed into which the composition has been mixed as a solid preparation should be made available ad libitum.Thus, a preferred use is also the subject of the invention in which the composition a) is provided as a solid preparation mixed with the low-protein feed for the poultry ad libitum or b) is provided as a drinking solution for the poultry separately from the low-protein feed, wherein the drinking solution and the low-protein feed are provided ad libitum.

[0026] In the context of the present invention, the term "ad libitum" is understood to mean an amount of low-protein feed, an amount of drinking solution, or an amount of low-protein feed into which the composition has been mixed, which exceeds the daily feed and drinking solution requirements for the total number of individuals in the fattening farm. Thus, according to the present invention, the feed or drinking solution should preferably be provided "ad libitum," i.e., in excess for the poultry's free use.

[0027] Thus, the preferred ad libitum use differs significantly from the specific administration of an active ingredient, which is administered, for example, daily in the form of a defined amount of 500 mg per day in single doses and independently of other foodstuffs. It is all the more surprising that the sole provision of the low-protein feed ad libitum, namely at the free disposal of the poultry, and of the composition containing guanidinoacetic acid and glycine, in particular a composition consisting of guanidinoacetic acid and glycine, leads to the desired result, namely an increase in the fattening performance of the poultry and / or an increase in the slaughter weight of the poultry and / or an improvement in the uniformity of the slaughter weight of the poultry.

[0028] It has been shown that the inventive use of guanidinoacetic acid in combination with glycine is not limited to the substances themselves. Rather, it has been shown that both guanidinoacetic acid as such, namely as the free acid, and also as a salt of guanidinoacetic acid can be used.

[0029] A particularly preferred salt is a salt selected from the group of alkali or alkaline earth metal salts of guanidinoacetic acid. Sodium guanidinoacetate, potassium guanidinoacetate, magnesium guanidinoacetate, or calcium guanidinoacetate are particularly preferred.

[0030] Furthermore, it has been shown that glycine can be used either as such, namely as the free acid, or in the form of a glycine salt. Particularly preferred is a salt selected from the group of alkali or alkaline earth salts of glycine, in particular sodium glycinate, potassium glycinate, magnesium glycinate, or calcium glycinate.

[0031] Thus, a preferred use of the present invention is also included in which the composition (i) guanidinoacetic acid as the free acid or in the form of a salt of this acid and / or (ii) glycine as the free acid or in the form of a salt of this acid, contains, in particular consists.

[0032] However, the use of a composition containing guanidinoacetic acid as the free acid and glycine as the free acid is particularly preferred. The use of a composition consisting of guanidinoacetic acid as the free acid and glycine as the free acid is even more preferred.

[0033] In connection with the underlying studies, it has been shown that the amounts of guanidinoacetic acid and glycine to be used are limited to a certain level and ratio. Particularly good results can be achieved if the guanidinoacetic acid is used in an amount of at least 0.01 wt.%, preferably at least 0.02 wt.%, more preferably at least 0.03 wt.%, more preferably at least 0.04 wt.%, and at the same time at most 0.20 wt.%, more preferably at most 0.15 wt.%, more preferably at most 0.12 wt.%, particularly preferably at most 0.10 wt.%, and most preferably at most 0.08 wt.% (in each case based on the low-protein feed).

[0034] If the guanidinoacetic acid and / or glycine are not used as a free acid but in the form of a salt, the weight information herein always refers to the proportion of guanidinoacetic acid in the guanidinoacetic acid salt or the proportion of glycine in the glycine salt.

[0035] Furthermore, good results can be achieved if the glycine is used in an amount of at least 0.01 wt.%, preferably at least 0.02 wt.%, more preferably at least 0.03 wt.%, more preferably at least 0.04 wt.% and at the same time at most 0.20 wt.%, more preferably at most 0.15 wt.%, more preferably at most 0.12 wt.%, particularly preferably at most 0.10 wt.% and most preferably at most 0.08 wt.% (in each case based on the low-protein feed).

[0036] According to the use according to the invention, it is therefore provided that the guanidinoacetic acid is used in an amount of 0.01 to 0.20 wt.%, preferably from 0.02 to 0.15 wt.% and particularly preferably from 0.04 to 0.10 wt.% (in each case based on the low-protein feed), and that the glycine is used in an amount of 0.01 to 0.20 wt.%, preferably from 0.02 to 0.15 wt.% and particularly preferably from 0.04 to 0.10 wt.% (in each case based on the low-protein feed).

[0037] According to a preferred embodiment of the invention, the use can be such that the composition is provided as a solid preparation mixed with the low-protein feed for the poultry. More preferably, the composition is provided as a solid preparation mixed with the low-protein feed for the poultry, wherein the composition contains the guanidinoacetic acid in an amount of 0.01 to 0.20 wt.%, preferably from 0.02 to 0.15 wt.% and particularly preferably from 0.04 to 0.10 wt.% (in each case based on the low-protein feed) and / or the glycine in an amount of 0.01 to 0.20 wt.%, preferably from 0.02 to 0.15 wt.% and particularly preferably from 0.04 to 0.10 wt.% (in each case based on the low-protein feed), in particular consisting of the stated amounts.

[0038] According to a further preferred embodiment of the invention, the use is such that the composition is provided as a solid preparation mixed with the low-protein feed for the poultry, wherein the composition consists of guanidinoacetic acid in an amount of 0.03 to 0.08 wt.% and glycine in an amount of 0.03 to 0.08 wt.% (in each case based on the low-protein feed).

[0039] Further preferably, a composition can be used which contains guanidinoacetic acid and glycine, in particular consists of guanidinoacetic acid and glycine, wherein the weight ratio of guanidinoacetic acid to glycine is in the range from 2:1 to 1:2, preferably from 1.8:1 to 1:1.8, further preferably from 1.5:1 to 1:1.5, particularly preferably from 1.3:1 to 1:1.3 and most preferably 1:1.

[0040] Particularly preferred is the use of a composition consisting of guanidinoacetic acid and glycine in equal parts.

[0041] According to a particularly preferred embodiment of the invention, the use is such that the composition is provided as a solid preparation mixed with the low-protein feed for the poultry, wherein the composition consists of guanidinoacetic acid in an amount of 0.03 to 0.08 wt.% and glycine in an amount of 0.03 to 0.08 wt.% (in each case based on the low-protein feed) and wherein the weight ratio of guanidinoacetic acid to glycine is in the range of 1.5:1 to 1:1.5, in particular 1:1.

[0042] According to a preferred embodiment of the invention, the composition can be used in such a way that it is provided as a drinking solution for the poultry, separate from the feed. Such drinking solutions contain water and the composition. Furthermore, the use can be particularly preferably carried out if the water used is drinking water, spring water, well water, or tap water.

[0043] Particularly preferably, such impregnation solutions contain water, guanidinoacetic acid in an amount of 0.05 to 1.2 g per liter of water and glycine in an amount of 0.05 to 1.2 g per liter of water.

[0044] Thus, according to a further idea, the use can also be such that the composition is provided as a drinking solution for the poultry and the drinking solution contains water, the guanidinoacetic acid in an amount of 0.05 to 1.2 g per 1 liter of water, in particular from 0.1 to 0.9 g per 1 liter of water, in particular from 0.15 to 0.6 g per 1 liter of water, particularly preferably from 0.2 to 0.5 g per 1 liter of water and the glycine in an amount of 0.05 g to 1.2 g per 1 liter of water, in particular from 0.1 to 0.9 g per 1 liter of water, in particular from 0.15 to 0.6 g per 1 liter of water, particularly preferably from 0.2 to 0.5 g per 1 liter of water.

[0045] More preferably, the use can be such that the composition is provided as a drinking solution for the poultry and the drinking solution contains water, the guanidinoacetic acid in an amount of 0.05 to 1.2 g per 1 liter of water and the glycine in an amount of 0.05 g to 1.2 g per 1 liter of water, wherein the weight ratio of guanidinoacetic acid to glycine is in the range of 1.5:1 to 1:1.5, in particular 1:1.

[0046] The invention described herein can be used for a wide variety of poultry. The composition containing guanidinoacetic acid and glycine, in particular consisting of guanidinoacetic acid and glycine, and the low-protein feed can particularly preferably be used for poultry selected from the group consisting of chickens, broilers, chickens, and chickens.

[0047] Furthermore, the studies underlying the invention have shown that the low-protein feed used should have a defined calorific value. On the one hand, the low-protein feed should not fall below a calorific value established for normal nutrition and healthy growth, and on the other hand, it should not exceed it to prevent obesity. Good results have been shown when the poultry feed has a calorific value of 8 MJ to 20 MJ per 1 kg of feed, in particular 10 MJ to 15 MJ per 1 kg of feed, and / or the feed is a balanced feed according to the Animal Nutrition Handbook, 3rd Revision, 2014, Section 12, Poultry Nutrition and Feeding.

[0048] Both the method and the use can be particularly preferably carried out if the low-protein feed comprises at least one cereal, cereal flour, cereal meal, or extracts thereof. Furthermore, a use in which at least one cereal, cereal flour, cereal meal, or extracts thereof is selected from the group: a. maize, maize flour, maize meal or an extract thereof, b. millet, millet flour, millet meal or an extract thereof, c. soya, soya flour, soya meal or an extract thereof, d. wheat, wheat flour, wheat meal or an extract thereof, e. barley, barley flour, barley meal or an extract thereof, f. sunflower, sunflower meal, sunflower meal or an extract thereof, and / or g. rapeseed, rapeseed meal or rapeseed extraction meal.

[0049] Furthermore, the use can be particularly preferably carried out if the low-protein feed comprises at least one further feed additive, in particular a further feed additive from the group of minerals, amino acids, and vitamins. This feed additive can most preferably be selected from the group consisting of calcium carbonate, mono- or dicalcium phosphate, lysine, methionine, threonine, tryptophan, valine, arginine, and vitamins, as well as mixtures thereof.

[0050] A preferred basic feed therefore essentially comprises maize or maize components, millet or millet components, wheat or wheat components, barley or barley components, sunflower or sunflower components.

[0051] In particular, the preferred feed contains only a limited amount of protein-rich feed from rapeseed and soybean plants.

[0052] In particular, the invention relates to a composition consisting of guanidinoacetic acid and glycine for use as a feed additive for poultry, in particular for fattening poultry, in the feeding of low-protein feed to increase the fattening performance and the fattening weight of the animals at the end of fattening and to improve the uniformity of the weight of the animals.

[0053] The preferred embodiments of the composition according to the invention are described in the uses according to the invention.

[0054] The following examples are intended to illustrate the present invention. Examples

[0055] 66,000 Ross 308 broiler chickens at 11 days of age, i.e., at the beginning of the grower phase, were evenly distributed among six identical housing units. They were fed pellets (<3 mm diameter, <7 mm length) until the end of the trial. The composition of the feed remained constant within each group and was not adjusted until the end of the trial.

[0056] The air temperature was between 20 and 23°C, with a humidity between 60 and 75%. Water was provided through nipple drinkers, with 12 animals per nipple, and the height of the nipple drinkers was adjusted according to the age of the animals. In the feed pan system, 45 animals shared one feed pan. The litter depth was 5 cm, and the litter was evenly distributed.

[0057] For Ross Broilers, for example, a crude protein content of 21.5 wt% is recommended between day 11 and day 24, and 19.5 wt% from day 25 until marketing. As a low-protein feed with a crude protein content at least 10% below the recommendations, a crude protein content of 17.5 wt% was therefore set. The crude protein content was determined by determining the nitrogen content of the finished feed mixture using the Kjeldahl method, assuming that proteins have a nitrogen content of 16 wt%.

[0058] The feed mixture was made from corn, soybean meal, soybean oil, calcium phosphate, grit, salt, sodium bicarbonate, and vitamin supplements. Additives per kg: Vitamin A 13,000 IU, Vitamin D3 5,000 IU, Vitamin E 100 mg, Copper 10 mg, and Selenium 0.42 mg. To produce the low-protein feed, the amount of corn was increased and the amount of soybean meal decreased. The methionine concentration was kept constant by adding it to the low-protein feed, resulting in 0.57% methionine in the feed for both variants. The metabolic energy was adjusted to 3200 kcal / kg.

[0059] The mix was otherwise prepared according to the recommendations of the Nutrition Specification for Ross Broiler, Table 2 [http: / / tmea.aviagen.com / assets / Tech_Center / Ross_Broiler / RossBroilerNutritionSpecs2019-EN.pdf].

[0060] The difference between the two feed mixtures was therefore in the crude protein content: the standard feed had a crude protein content of 19.8 wt%, the low-protein feed had a crude protein content of 17.5 wt%.

[0061] Four additional low-protein feed variants were prepared from the low-protein feed by adding guanidinoacetic acid (GAA), glycine (Gly), or guanidinoacetic acid and glycine. Pellets of the size described above were extruded with all feed mixtures.

[0062] The following feeds were available: Experiment 1 (V-1): Standard diet with 19.8 wt% crude protein Experiment 2 (V-2): Low-protein diet with 17.5 wt% crude protein Experiment 3 (V-3): Low-protein diet with 17.5 wt% crude protein and 0.05 wt% GAA Experiment 4 (V-4): Low-protein diet with 17.5 wt% crude protein and 0.1 wt% GAA Experiment 5 (V-5): Low-protein diet with 17.5 wt% crude protein and 0.05 wt% Gly Experiment 6 (V-6): Low-protein diet with 17.5 wt% crude protein and 0.05 wt% each of GAA and Gly

[0063] The animals in the six groups were provided with the above-described feed and water ad libitum. At the end of the experiment, after day 38, the animals were removed and their average live weight was determined. Losses in the stable were comparable in all test groups, ranging from 2.18% to 2.30%.

[0064] To determine the standard deviation (SD), 100 animals from each experimental group were individually weighed during the sampling process, and the standard deviation was determined from this. To make the standard deviation of the different experiments comparable, the standard deviation of Experiment 1 was standardized to 1 and referred to as the "standardized standard deviation" (SDnorm). The SDnorm of Experiments 2 to 6 was determined by dividing the respective standard deviation by the standard deviation of Experiment 1. The results are presented in Table 1 below. Table 1: Results of the feeding study V-1 V-2 V-3 V-4 V-5 V-6 Final weight [g] 2120 2005 2034 2027 2016 2115 SD [g] 207 271 243 237 266 221 SD standard 1 1,31 1,17 1,14 1,29 1,07

[0065] As expected, the highest final weight of 2120 g and the smallest standard deviation from the mean final live weight were achieved in Trial 1, where the feed composition complied with the recommendations. A low-protein diet without any additional supplements (Trial 2), i.e., a 10% reduction in protein in the feed compared to the official recommendations, resulted in a significantly reduced final weight of 2005 g. The SDnorm of 1.31 was significantly higher than the reference value of 1, demonstrating the considerable inhomogeneity of the herd.

[0066] Both the addition of GAA at various concentrations in trials 3 and 4 and the addition of glycine in trial 5 resulted in only a slight improvement in final weight relative to the low-protein diet of trial 2, namely from 2005 g to 2034 g, 2027 g, and 2016 g. However, particularly when fed with GAA in trials 3 and 4, improved herd uniformity was achieved, with SDnorm values of 1.17 and 1.14, respectively. This represents a significant improvement relative to the 1.31 achieved with the low-protein diet of trial 2, but is still significantly different from the uniformity achieved with the standard diet in trial 1.

[0067] In trial 6, in which the feed was supplemented with GAA and glycine, a final weight of 2115 g was achieved, almost equal to that of control group 1. The SD norm of 1.07 was only slightly higher than the reference value of trial 1.

[0068] It has been shown, quite surprisingly, that supplementing a low-protein basic feed with glycine and guanidinoacetic acid almost completely compensates for the disadvantages of a low-protein diet on growth and uniformity.

Claims

1. Use of i) a composition comprising guanidinoacetic acid and glycine, wherein the composition comprises glycine as a free acid or in the form of a salt of this acid; and ii) a low protein feed for poultry having a crude protein content in the range of 14.0 to 18.5 wt. % (based on the total weight of the feed) during fattening from the 11th to the 39th day of life of the poultry, for increasing the fattening performance of the poultry and / or for increasing the slaughter weight of the poultry and / or for improving the uniformity of the slaughter weight of the poultry, wherein the guanidinoacetic acid is used in an amount of from 0.01 to 0.20 wt. % based on the low protein feed and wherein the glycine is used in an amount of from 0.01 to 0.20 wt. % based on the low protein feed.

2. Use according to claim 1, characterized in that the composition is provided as a solid preparation mixed with the low protein feed for the poultry or, that the composition is provided as a drinkable solution for the poultry separately from the low protein feed.

3. Use according to any one of the preceding claims, characterized in that the composition comprises guanidinoacetic acid as a free acid or in the form of a salt of this acid.

4. Use according to any one of the preceding claims, characterized in that the guanidinoacetic acid is used in the form of a salt of the guanidinoacetic acid, the salt being selected from the group of alkali metal or alkaline earth metal salts of the guanidinoacetic acid, in particular sodium guanidinoacetate, potassium guanidinoacetate, magnesium guanidinoacetate or calcium guanidinoacetate.

5. Use according to at least one of the preceding claims, characterized in that the glycine is used in the form of a salt of the glycine, the salt being selected from the group of alkali metal or alkaline earth metal salts of the glycine, in particular sodium glycinate, potassium glycinate, magnesium glycinate or calcium glycinate.

6. Use according to any one of the preceding claims, characterized in that the guanidinoacetic acid is used in an amount of from 0.02 to 0.15 wt. % and particularly preferably from 0.04 to 0.10 wt. %, in each case based on the low protein feed.

7. Use according to any one of the preceding claims, characterized in that the glycine is used in an amount of from 0.02 to 0.15 wt. % and particularly preferably from 0.04 to 0.10 wt. %, in each case based on the low protein feed.

8. Use according to any one of the preceding claims, characterized in that the composition is provided as a drinkable solution for the poultry and the drinkable solution comprises water, the guanidinoacetic acid in an amount of 0.05 to 1.2 g per 1l of water and the glycine in an amount of 0.05 g to 1.2 g per 1 l of water.

9. Use according to any one of the preceding claims, characterized in that the guanidinoacetic acid and the glycine are used in a weight ratio of guanidinoacetic acid to glycine ranging from 2 : 1 to 1 : 2.

10. Use according to any one of the preceding claims, characterized in that the poultry is selected from the group consisting of chickens, broilers, young male chickens, young female chickens.

11. Use according to any one of the preceding claims for improvement of the uniformity of the slaughter weight of the poultry.

12. Use according to any one of the preceding claims, wherein the low protein feed has a calorific value of 8 MJ / kg to 20 MJ / kg.