Chelates in Animal Nutrition
Chelates are organic forms of essential minerals such as copper, iron, manganese and zinc. Animals absorb, digest and use mineral chelates better than inorganic minerals. This means that lower concentrations can be used in animal feeds. In addition, animals fed chelated sources of essential trace minerals excrete lower amounts in their feces and so there is less environmental contamination. Mineral chelates also offer health and welfare benefits in animal nutrition (McCartney, 2008).
1. History of mineral chelates in animal feeds
Since the 1950s, animal feeds have been supplemented with essential trace minerals such as cobalt (Co), copper (Cu), iron (Fe), iodine (I), manganese (Mn), molybdenum (Mo), selenium (Se) and zinc (Zn). Initially, such supplementation was by means of inorganic salts of essential trace elements. From the 1960s onwards, genetic improvement of farm livestock resulted in increased nutritional requirements for these nutrients. Chelated minerals were developed in the 1980s and 1990s. Trace mineral chelates have proven to be better than inorganic minerals in meeting the nutritional needs of modern farm animals.
2. Role of essential trace minerals in animals
The objective of supplementation with trace minerals is to avoid a variety of deficiency diseases. Trace minerals carry out key functions in relation to many metabolic processes, most notably as catalysts for enzymes and hormones, and are essential for optimum health, growth and productivity. For example, supplementary minerals help ensure good growth, bone development, feathering in birds, hoof, skin and hair quality in mammals, enzyme structure and functions, and appetite. Deficiency of trace minerals affect many metabolic processes and so may be manifested by different symptoms, such as poor growth and appetite, reproductive failures, impaired immune responses, and general ill-thrift. From the 1950s to the 1990s most trace mineral supplementation of animal diets was in the form of inorganic minerals, and these largely eradicated associated deficiency diseases in farm animals.
3. Need for improved sources of essential trace minerals
In recent decades, global food animal production has intensified and genetic potential for growth and yields has improved. As a result commercial tendencies have been to increase trace mineral supplementation rates, in order to allow for the greater mineral requirements of superior stock reared under industrial conditions. Increasing the concentration of inorganic minerals in animal diets has led to several problems. For example, the use of high Cu in swine and poultry rations has caused accidental Cu poisoning in more sensitive animals, such as sheep grazing pastures fertilised with pig or poultry manure//ec.europa.eu/food/fs/sc/scan/index_en.html
. Secondly, inorganic minerals may form insoluble complexes with other dietary agents resulting in low absorption. In addition, it is thought that the positive charge of many inorganic minerals reduces access to the enterocytes due to repulsion by the negatively charged mucin layer and competition for binding sites. Finally, the poor retention and high excretion rates of inorganic minerals led to environmental concerns during the 1980s and 1990s, especially in Europe//ec.europa.eu/food/fs/sc/scan/index_en.html
. The EU is concerned about possible detrimental effects of excess supplementation with trace minerals on the environment or human and animal health, and so in 2003 legislated a reduction in permitted feed concentrations of several trace metals (Co, Cu, Fe, Mn and Zn)//eur-lex.europa.eu/en/index.htm
. Fortunately, research in trace element nutrition has led to the development of more bioavailable organic minerals, including trace minerals derived from chelates. Chelates allow a lower supplementation rate of trace minerals with an equivalent or improved effect on animal health, growth and productivity.
4. Chelates and proteinates
Chelates are organic molecules, normally consisting of 2 organic parts with an essential trace mineral occupying a central position and held in place by covalent bonding. Proteinates are a particular type of chelate, in which the mineral is chelated with short-chain peptides and amino acids derived from hydrolysed soy proteins, and containing in the order of 10-20% of the essential trace mineral.
5. Research on chelates in animal nutrition
Du et al (1996)1657–1663.
concluded that the utilisation of organic Cu from a copper proteinate (Bioplex Cu, Alltech) or copper lysine (CuPlex 80, Zinpro) were higher than that of inorganic Cu sulfate when fed to rats in the presence and absence of elemental Zn or Fe. The data suggest that, unlike inorganic Cu, organic Cu chelates exhibit absorption and excretion mechanisms that do not interfere with Fe. Bioplex Cu also achieved higher liver Zn, suggesting less interference at gut absorption sites in comparison with the other forms of Cu.
Kessler et al (2003)161-171. compared a Zn proteinate (Bioplex Zn, Alltech), a Zn polysaccharide complex (Carbosan Zn, Quali Tech) and ZnO (inorganic zinc oxide) in bull beef cattle, and concluded that the organic forms resulted in some improvement in hoof claw quality.
In a review article of the role of minerals in fertility and reproductive diseases of dairy cattle Wilde (2006) highlights that organic forms of Zn are retained better than inorganic sources and so may provide greater benefit in disease prevention, notably mastitis and lameness.
Ryan et al (2002)J. P. Ryan, P. Kearns and T. Quinn (2002) Bioavailability of dietary copper and zinc in adult Texel sheep: A comparative study of the effects of sulfate and Bioplex supplementation. Irish Veterinary Journal 55(5):May 2002,221-224. compared the bioavailability of Cu and Zn proteinates (Bioplex, Alltech) in sheep with the inorganic sulfate forms, at "low" and "high" supplementation rates. Bioplex Cu and Zn at the lower rates caused significantly greater increases in plasma concentrations than the corresponding treatments with Zn sulfate (p<0.05) and Cu sulfate (p<0.01). In addition, Bioplex Zn supplementation resulted in significantly greater hoof horn Zn content than did Zn sulfate (p<0.05). At the "low" supplementation rate Bioplex Zn achieved better hoof quality than Zn sulfate (p<0.05). The data suggest that Cu and Zn proteinates are more readily absorbed and more easily deposited in key tissues such as hooves, in comparison with inorganic Zn forms.
In weaned piglets, Carlson et al (2004)1359–1366. evaluated various supplementation rates of organic Zn in the form of a proteinate (Bioplex Zn, Alltech) or as a polysaccharide complex (Sea-Questra Min Zn, Quali Tech), and compared these with ZnO (zinc oxide) at 2,000 ppm. Feeding lower concentrations of organic Zn greatly decreased the amount of Zn excreted in comparison with inorganic Zn, without loss of growth performance.
Veum et al (2004) 1062–1070.studied a Cu proteinate (Bioplex, Alltech) in weaned pigs in comparison with inorganic Cu sulfate. Piglet performance was consistently better with organic Cu at 50 to 100 ppm, in comparison with inorganic Cu at 250 ppm. In addition, organic Cu increased Cu absorption and retention, and decreased Cu excretion 77% and 61% respectively, compared with 250 ppm inorganic Cu.
Guo et al (2003)143-150 investigated the effects of an Mg proteinate (Bioplex Mg, Alltech) in broiler chickens in comparison with MgO (magnesium oxide) and an unsupplemented control group. Diets for fattening chicken are not normally supplemented with Mg, but this study indicated positive effects on performance and meat quality. During the first 3 weeks of life, the Mg proteinate improved feed efficiency significantly in comparison with both the inorganic MgO and the negative control group (p<0.05). Thigh meat pH and oxidative deterioration during storage were also studied. The Mg proteinate increased thigh meat pH in comparison with the negative control ((p<0.05). Mg supplementation significantly reduced chemical indicators (TBARS) of oxidative deterioration in liver and thigh muscle (p<0.01), with Mg proteinate significantly more efficient than MgO (p<0.01). The data suggest that organic Mg in the form of a proteinate is capable of reducing oxidation, and so improve chicken meat quality.
A Zn proteinate supplement (Bioplex Zn, Alltech) was compared with Zn sulfate in broiler chickens (Ao et al 2006)T. Ao, J.L. Pierce, R. Power, K.A. Dawson, A.J. Pescatore, A.H. Cantor and M.J. Ford (2006) Investigation of relative bioavailability value and requirement of Bioplex Zinc (organic zinc) for chicks. J. Poultry. Sci 5 (9): 808:811. Weight gain and feed intake increased quadratically (p<0.05) with increasing Zn concentrations from the proteinate and linearly with Zn sulfate. The relative bioavailability of the Zn proteinate was 183% and 157% of Zn sulfate for weight gain and tibia Zn, respectively. The authors concluded that the supplemental concentration of Zn required in corn-soy diets for broilers from 1–21 days of age would be 9.8 mg/kg diet (as Zn proteinate) and 20.1 mg/kg diet (as Zn sulfate), respectively.
Nollet et al (2007)592–597 studied the effect of replacing inorganic minerals with organic proteinates (Bioplex, Alltech) in broiler chickens. One group of chickens received inorganic sulfates of Cu (12 ppm), Fe (45 ppm), Mn (70 ppm) and Zn (37 ppm) and their performance was compared to a similar group supplemented with proteinates of Cu (2.5 ppm), Fe, Mn, and Zn (all at 10 ppm). There were no differences in performance between the birds fed the “high” inorganic minerals and the birds fed the “low” organic chelates, but significantly lower faecal mineral excretion rates were observed for birds fed the organic mineral proteinates (p<0.05). Faecal concentrations of Cu, Fe, Mn and Zn were 55%, 73%, 46% and 63%, respectively, of control birds fed inorganic minerals.
A broiler study reported by Peric et al (2007)L. Peric, L. Nollet, N. Miloševic and D. Zikic (2007) Effect of Bioplex and Sel-Plex substituting inorganic trace mineral sources on performance of broilers. Arch.Geflügelk., 71 (3). S. 122–129. also compared inorganic and organic mineral supplementation in broiler chickens. Control birds were fed Cu, Fe, Mn Se and Zn in inorganic forms (15 ppm Cu 15 from sulfate; 60 ppm Fe from sulfate; 60 ppm Mn from oxide; 0.3 ppm Se as Na selenite; and 60 ppm Zn from oxide) and compared with 3 treatment groups supplemented with organic forms (Bioplex/Sel-Plex, Alltech: 5, 10 & 15 ppm Cu 15 from Cu proteinate; 15, 30 & 45 ppm Fe from Fe proteinate; 15, 30 & 45 ppm Mn from Mn proteinate; 0.1, 0.2 & 0.3 ppm organic Se from yeast; and 15, 30 & 45 ppm Zn from Zn proteinate). Apart from improved feathering, most likely associated with the presence of organic Se from yeast, there were no significant performance differences between birds fed inorganic and organic minerals. The authors concluded that the use of organic trace minerals permits a reduction of at least 33% in supplement rates in comparison with inorganic minerals, without compromising performance.
- SCAN (2003a) Opinion of the Scientific Committee for Animal Nutrition on the use of copper in feedingstuffs. http://ec.europa.eu/food/fs/sc/scan/index_en.html
- SCAN (2003b) Opinion of the Scientific Committee for Animal Nutrition on the use of zinc in feedingstuffs. http://ec.europa.eu/food/fs/sc/scan/index_en.html
- Commission Regulation (EC) No 1334/2003 of 25 July 2003 amending the conditions for authorisation of a number of additives in feedingstuffs belonging to the group of trace elements. 26.7.2003 EN Official Journal of the European Union L 187/11 http://eur-lex.europa.eu/en/index.htm
- E. McCartney (2008) Trace minerals in poultry nutrition – sourcing safe minerals, organically? World Poultry 24:Nº 2, 14-15. www.WorldPoultry.net
- Z. Du, R.W. Hemken, J.A. Jackson and D.S. Trammell (1996) Utilization of copper in copper proteinate, copper lysine and cupric sulfate using the rat as an experimental model. J. Anim. Sci. 74:1657–1663.
- J. Kessler, I. Morel, P.A. Dufey, A. Gutzwiller, A. Stern and H. Geyer (2003). Effect of organic zinc sources on performance, zinc status and carcass, meat and claw quality in fattening bulls. Livestock Prod. Sci. 81:161-171.
- D. Wilde (2006). Influence of macro and micro minerals in the peri-parturient period on fertility in dairy cattle. Anim. Reprod. Sci. 96:240-249.
- J. P. Ryan, P. Kearns and T. Quinn (2002) Bioavailability of dietary copper and zinc in adult Texel sheep: A comparative study of the effects of sulfate and Bioplex supplementation. Irish Veterinary Journal 55(5):May 2002,221-224.
- M.S. Carlson, C.A. Boren, C.Wu, C.E. Huntington, D.W. Bollinger and T.L. Veum (2004) Evaluation of various inclusion rates of organic zinc either as polysaccharide or proteinate complex on the growth performance, plasma and excretion of nursery pigs. J. Anim. Sci. 28:1359–1366.
- T.L. Veum, M.S. Carlson, C.W. Wu, D.W. Bollinger and M.R. Ellersieck (2004) Copper proteinate in weanling pig diets for enhancing growth performance and reducing fecal copper excretion compared with copper sulfate. J. Anim. Sci.
- Y. Guo, G. Zhang, J. Yuan and W. Nie. (2003) Effects of source and level of magnesium and Vitamin E on prevention of hepatic peroxidation and oxidative deterioration of broiler meat. Anim. Feed Sci.Tech. 107:143-150
- T. Ao, J.L. Pierce, R. Power, K.A. Dawson, A.J. Pescatore, A.H. Cantor and M.J. Ford (2006) Investigation of relative bioavailability value and requirement of Bioplex Zinc (organic zinc) for chicks. J. Poultry. Sci 5 (9): 808:811
- L. Nollet, J. D. van der Klis, M. Lensing and P. Spring. (2007) The Effect of Replacing Inorganic With Organic Trace Minerals in Broiler Diets on Productive Performance and Mineral Excretion. J. Appl. Poult. Res. 16:592–597
- L. Peric, L. Nollet, N. Miloševic and D. Zikic (2007) Effect of Bioplex and Sel-Plex substituting inorganic trace mineral sources on performance of broilers. Arch.Geflügelk., 71 (3). S. 122–129.