Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.
2007
Volume 10
Issue 1
Topic:
Veterinary Medicine
ELECTRONIC
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Słupczyńska M. , Kinal S. , Lubojemska B. 2007. UTILIZATION OF ORGANIC AND INORGANIC FORMS OF ZINC IN SHEEP NUTRITION, EJPAU 10(1), #19.
Available Online: http://www.ejpau.media.pl/volume10/issue1/art-19.html

UTILIZATION OF ORGANIC AND INORGANIC FORMS OF ZINC IN SHEEP NUTRITION

Maja Słupczyńska, Stefania Kinal, Barbara Lubojemska
Department of Animal Nutrition and Feed Science, Wrocław University of Environmental and Life Sciences, Poland

 

ABSTRACT

The bioavailability of zinc from feed rations contained zinc oxide and Zn-glycine was determined in growing lambs’ investigation. Apparent absorption and retention of zinc as well as content of zinc in selected soft tissues were accepted as an indices of zinc bioavailability. Apparent absorption and zinc retention were greater in lambs receiving Zn-glycine than in the control group. Similar tendency for content of that microelement in kidneys and liver was stated. Obtained data point out better bioavaliability of zinc form Zn-glycine than zinc oxide.

Key words: zinc, zinc oxide, Zn-glycine, apparent absorption, bioavailability.

INTRODUCTION

The availability of zinc in animal nutrition depends on the content of that trace element in fodders and mineral additives as well as forms of zinc and physiologic properties of organism. Bioavailabilty of zinc from feed ration can be reduce by compounds like phytins and tannins forming with zinc insoluble complex as well as antagonistic to zinc elements – Cu, Fe, Ca and P [6,15]. Applied in animal nutrition inorganic forms of zinc (salts, oxides, sulphates) can get in various interaction with feed ingredients and forming complexes unavailable for animals. Organic forms of zinc are characterized high stability in variable environment of digestive tract [8]. Available papers states that organic forms of zinc can be better utilized by animals than their inorganic equivalents [5,7,14,].The results of research of this subject are ambiguous and sometimes controversial what is made that conducting continue research seems to be well-founded.

The aim of this study was to determine bioavailability of zinc from feed concentrate mixtures containing zinc oxide and Zn-glycine in growing lambs.

MATERIAL AND METHODS

The experiment was performed on 24 lambs (12♂ i 12♀) cross-breed Polish Merino Sheep x Romanov Sheep x Charolaise. The lambs with average body weight of 20kg were randomly assigned to two feeding groups, 12 lambs in each group (6 rams and 6 ewes). During the period of fattening the lambs were fed with concentrate mixtures and meadow hay. The fodder was given in amount 0.375-1 and 0.3-0.5 kg/day/per head. According to NRC standards (2001) content of zinc in feed rations was 90mg/kg DM Experimental factor was various forms of zinc in premixes added to concentrate mixtures. In group I (control) zinc was added as an oxide while in groups II experimental as a Zn-glycine.

Basic chemical analysis of the fodder was carried out on the fodders in order to identify the nutrients and mineral ingredients content. Calcium, magnesium, sodium, copper, zinc and manganese were determined after previous mineralization by atomic absorption using AAS-3 apparatus, while phosphorus was determined by spectrofotometric measurement as complex with vanadate [1].

The content of concentrate mixtures for lambs and nutritive value is shown in Tables 1 and 2.

Table 1. Composition of concentrate mixtures for lambs

Components

Mixture content (%)

Barley ground

37.1

Wheat ground

30.0

Soybean meal

10.0

Rapeseed meal

10.0

Wheat bran

10.0

Salt

0.3

Limestone

0.6

Premix

2.0

Total

100.0

Table 2. Nutrients and mineral ingredients content in lamb fodders

Item

Fodders

Concentrate mixtures

Meadow hay

Nutrients [%]:
Dry matter


88.75


92.11

Crude protein

17.66

9.44

Ether extract

2.22

1.25

Crude fibre

5.52

35.13

Crude ash

4.53

3.98

Nitrogen free extract

58.82

42.31

Minerals ingredients:

   

Major elements[g/kg]

   

Ca – calcium

3.73

3.74

Mg – magnesium

2.15

2.02

P – phosphorus

4.92

1.70

Na – sodium

4.05

1.84

Trace elements [mg/kg]

   

Cu – copper

14.19

7.98

Zn – zinc

89.77

14.92

Mn – manganese

107.98

153.09

Six rams from each group, after their body weight has reached 30 kg were assigned to digestibility-balance tests. The amounts of fodders intake and excreted faeces and urine were measured during the collection period. After previous wet mineralization in excrements zinc and copper content were determined by atomic absorption spectrofotometry (AAS-3, Zeiss) [1].

Obtained data allowed for estimation of the apparent absorption and retention of zinc and copper by balance method. 4 ♂ and 4♀ from each group, after their body weight has reached 35kg were slaughtered and soft tissues (liver, brain and kidneys) were sampled. In freeze-dried tissues zinc content was determined by atomic absorption spectrofotomety (AAS-3, Zeiss) [1]. Obtained data were calculated on fresh tissues.

All obtained data were analyzed statistically using test t-Student.

RESULTS

Obtained data concerning apparent absorption and retention of zinc and copper are presented in Table 3.

Table 3. Apparent absorption and retention of zinc and copper in lambs
(mean, ±std)

Item

Zn – zinc

Cu – copper

Feeding groups

I
ZnO

II
Zn-gly

I
ZnO

II
Zn-gly

Intake [mg]

121.48

121.48

20.84

20.84

Excreted [mg]:

       

- in faeces

41.78
±5.53

37.30
±9.32

3.51
±1.45

2.89
±1.04

- in urine

7.65
±5.77

7.44
±2.08

2.69
±1.66

2.67
±0.81

Digested [mg]
  
Apparent absorption [%]

79.69a
±5.53
65.60a
±4.55

84.18b
±9.32
69.29b ±3.68

17.33
±1.45
83.15
±6.95

17.95
±1.04
86.14
±4.99

Retention [mg/d/per head]

72.04a
±5.24

76.74b
±6.82

14.64
±2.41

15.28
±1.13

a, b P < 0.05

Rams from both feeding groups received identical quantities of zinc and copper in the daily rations, while the amount of excreted elements varied. The higher level of zinc both in faeces and in urine was excreted by rams from control group I, which receive this element in the oxide form, while the amount of zinc especially in faeces was lower in the group fed with supplementation of zinc glycine (P≤0.05) (Table 3). This significantly influenced apparent absorption and retention of this trace element which may indicate its better bioavailability. Despite the fact that copper is a zinc antagonist, we may assume that Zn-glycine has a positive influence on the level of copper absorption and retention.

The rams from experimental group (Zn-Gly) excreted less copper in excrements than lambs from the control group. Apparent absorption of copper was slightly higher in the experimental groups but the differences were not statistically valid (Table 3). Due to the fact that copper in sheep nutrient rations came from feeding fodders it might be supposed that organic form of zinc – Zn-Gly could have profitable influence on copper absorption.

Obtained data concerning contents of zinc in lambs’ soft tissues are shown in Table 4.

Table 4. Content of zinc [mg/kg] in lambs soft tissues

Tissues

Feeding groups

I-control - ZnO

II-experimental - Zn-Gly

mean

std

mean

std

Liver

34.53a

±2.96

38.10b

±1.92

Kidneys

20.73A

±0.65

23.29B

±1.29

Brain

19.17

±1.97

17.59

±1.49

A, B P < 0.01
a, b P < 0.05

Zinc content in kidneys of lambs received Zn-glycine was by 11.1% higher (P≤0.01) than in those receiving zinc oxide. Supplementation of Zn-glycine to animals also caused an increase by 7.9% (P≤0.05) of content of this element in lamb liver. Concentration of zinc in the brain was lower than in animals receiving zinc oxide (Table 4), yet the differences found have not been confirmed in statistics.

DISCUSSION

Higher level of apparent absorption and retention of zinc in lambs receiving the organic form of zinc (Zn-glycine) was showed. Korniewicz et al. [7] also stated that zinc apparent absorption and retention of zinc were higher when applying amino-acid zinc chelate in lamb feeding than when zinc oxide was used. The research results related to apparent absorption of zinc were higher than the values obtained by Kinal et al. [5] after supplying sheep with zinc bioplexes. Słupczyńska [13] in experiment conducted on lambs indicated that animals receiving amino acid chelates (Zn-lysine, Zn-metionine and Zn-glycine) had higher apparent absorption and retention of zinc then animals receiving zinc oxide and apparent absorption and retention of zinc by lambs received amino acid chelates of Zn were vary and was the higher for Zn-Lysine. On the other hand Spears [15] in his research on lambs stated that the apparent absorption of zinc from Zn-methionine and from the oxide was comparable and Zn retention from the organic form of zinc was higher, which may point to better bioavailability of this micro-element from Zn-methionine than from the oxide.

According to Kirchgessner [6], the apparent and true absorption are directly linked to bioavailability when it is possible to provide such quantity of microelements that would satisfy the animals’ needs. In opinion of some authors [2,3] and in opinion of the Scientific Commitete for Animal Nutrition on the Use of Zinc of Feeding Stuffs (2003) good indices of zinc availability are the content of zinc in the liver, metalothionein activity, cumulation of zinc in bones as well as zinc level in blood serum.

Supplying Zn-glycine to concentrate mixture for lambs caused an increase of the content of zinc in the liver (P < 0.05) and in the kidneys (P < 0.01). For this reason, we may assume that bioavailability of zinc from Zn-glycine was better than from zinc oxide.

Słupczyńska [13] obtained a higher content of zinc in the soft and hard tissues (ribs) supplying Zn-glycin in comparison with zinc oxide. Also Rojas et al. [12] after supplying zinc oxide and zinc sulphate as well as Zn-methionine and Zn-lysine to lambs proved that in the soft tissues of lambs receiving Zn in the form of oxide, zinc content was lower than for the organic forms of zinc – Zn-methionine and Zn-lysine.

There is lack numerous data of analogical experiments conducted on ruminants. In experiments conducted on broilers Johnson [4], Swiętkiewicz et al. [16], Tronina [17] also indicated that application in premixes organic forms of zinc – Zn-methionine and Zn-glicyne, amino acid complexes caused increase of zinc apparent absorption and retention as well as the content of zinc in hard and soft tissues in comparison to birds received inorganic forms of zinc – oxide and sulphate. On the other hand Pimental et. al [11] given to broilers Zn-methionine and zinc oxide indicated that the content of this microelement in bones, liver and pancreas did not depend on the form of applied compounds but on the level of zinc in ration.

CONCLUSIONS

The result of the research carried out on growing lambs point to better absorption of zinc from Zn-glycine than from the oxide. This is confirmed by a higher level of the apparent absorption and retention of zinc as well as by the higher content of this micro-element in lamb liver and kidneys, which proves better bioavailability of zinc from the organic form of this element, namely Zn-glycine. Taking into consideration that on feed market are available new zinc compounds, especially bounded with amino acids and the data of experiments on animals with application of this compounds are unclear it is necessity of conducting experiments on application this forms in animal feeding.

REFERENCES

  1. AOAC, 2005. Official Methods of Analysis of the Association of Official Analytical Chemists. Association of Official Analytical Chemists, Arlington, Virginia, USA.

  2. Baker H.D., Ammerman C.B., Lewis A.J. 1995. Zinc bioavailability. Bioavailability of nutrients for animals: amino acids, minerals and vitamins. Academic Press, San Diego, USA, 367-398.

  3. Dymnicka M. 1994. Badania niektórych wskazników fizjologicznych i makroelementów we krwi jako jedna z metod wykrywania niedoborów pokarmowych i mineralnych u krów mlecznych [The estimation of some physiological indices and macro elements in blood as method of detection deficiency of nutrients and minerals for dairy cows]. Konf. Nauk.: “Zwiazki mineralne w żywieniu zwierzat”. 08-09.09.1994. Poznań, 130-134 [in Polish].

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  5. Kinal S. 2005. Physical, chemical and biological determination of different forms of zinc, copper and manganese in growing sheep nutrition. Pol. J. Env., vol. 14, supp.II, 115-121.

  6. Kirchgessner M., 1993. Underwood Memorial Lecture. Homeostasis and homeorhesis in trace element metabolism. In Trace Elelments in Man and Animals – TEMA B (Anke M., Meissner D. and Mills C.F., eds.) Verlag Media Toristik Dresden, Germany, pp. 4-21.

  7. Korniewicz A., Kinal S., Paleczek B., Słupczyńska M. 2002. The application of zinc in oxide and chelate form in sheep nutrition. Chemistry for Agriculture vol.3, pp. 274-281.

  8. Matyka S., Korol W. 1997. Struktury mineralno-organiczne (biopleksy) w produkcji i użytkowaniu pasz przemysłowych [The mineral-organic structures (bioplexes) in production and use of industry made feeds]. Referaty i Doniesienia II Konferencji Naukowej, 22-23 IX 1997 Balice, Kraków pp. 67-84 [in Polish].

  9. National Research Council. 2001. Nutrient Requirements for sheep. Seventh revised edition. National Academic Press, Washington D.C.

  10. Opinion of the Scientific Commitettee for Animal Nutrition on the use of zinc in feeding stuffs – 2003.

  11. Pimental J.L., Cook M.E., Greger J.L. 1991. Immune response to chicks fed various levels of zinc. Poult. Sci., 70, 947-954.

  12. Rojas L.X., McDowell L.R., Cousins R.J., Martin F.G., Wilkinson N.S., Johanson A.B., Velasqez J.B. 1995. Relative bioavability of two organic and two inorganic zinc sources fed to sheep. J. Anim. Sci. 73, pp. 1202 – 1207.

  13. Słupczyńska 2005. Chemiczna i biologiczna ocena różnych form cynku w żywieniu owiec [Chemical and biological estimation of different forms of zinc in lambs feeding]. Praca doktorska, Akademia Rolnicza we Wrocławiu [in Polish].

  14. Spears J. W. 1996. Organic trace minerals in ruminant nutrition. Anim. Feed Sci. Tech. 58, pp.151-163.

  15. Spears J.W. 1989. Zinc methionine for ruminants: Relative bioavaibility of zinc in lambs and effect of growth and performance of growing heifers. J. Anim. Sci. 67: pp.835-852.

  16. Swiatkiewicz S., Koreleski J., Zhong D., 2001. The bioavailability of zinc from inorganic and organic sources in broiler chickens as affected by addition of phytase. J. Anim. Feed Sci., 10: 317-328.

  17. Tronina W. 2006. Bioprzyswajalnosc cynku, selenu i chromu z różnych zwiazków chemicznych u kurczat rzeznych [Bioavailability of zinc, selenium and chromium from different chemical compounds in broiler chickens]. Praca doktorska, Akademia Rolnicza we Wrocławiu [in Polish].

 

Accepted for print: 27.01.2007


Maja Słupczyńska
Department of Animal Nutrition and Feed Science,
Wrocław University of Environmental and Life Sciences, Poland
J. Chełmonskiego 38C, 51-630 Wrocław, Poland

Stefania Kinal
Department of Animal Nutrition and Feed Science,
Wrocław University of Environmental and Life Sciences, Poland
J. Chełmonskiego 38C, 51-630 Wrocław, Poland
phone: 71 320 58 29
email: stefania.kinal@up.wroc.pl

Barbara Lubojemska
Department of Animal Nutrition and Feed Science,
Wrocław University of Environmental and Life Sciences, Poland
Chełmonskiego 38d, 51-630 Wrocław, Poland

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