EFFECT of MINERAL ADSORBENTS in
POULTRY PRODUCTION
D. Karanovic1, V. Djermanovic2, S. Mitrovic2, V. Radovi1, D. Okanovic3, S. Filipovic3 y V. Djekic4 Department of Animal Husbandry, Faculty of Agronomy, University of Kragujevac, Cacak, Serbia
1
Institute of Zootechnic, Faculty of Agriculture, University of Belgrade, Belgrade (Serbia)
2
Institute for food technology in Novi Sad (Serbia)
3
Center of Small Grains, Kragujevac, (Serbia)
4
1
The quality of poultry feed is an important precondition to achieve optimal production results, and the preservation of the health status of animals, especially in intensive livestock production, hence it is necessary to control both raw materials and finished feed mixtures. The presence of fungi (moulds) in food for animals is a natural phenomenon, not an exception.
Sources of contamination of poultry feed with fungi and resulting mycotoxins vary, starting with raw materials (e.g. corn as the most common component) during harvest and transport, during storage of raw materials and finished products, as well as in the production process and manipulation of poultry feed.
MINERAL ADSORBENTS Mineral adsorbents are increasingly used in poultry production, especially in the nutrition of various types and categories of poultry, to control fungal contamination.
Using different mineral adsorbents
In addition, the use of mineral
in poultry nutrition can prevent the
adsorbents in poultry feeds has
losses due to mycotoxicosis. It can
application in neutralising the
also prevent appearance of toxic
harmful effects of mycotoxins in
residues in poultry products, improve
buildings where poultry is reared.
production and reproductive ability of birds, and contribute to improving the quality of poultry products.
2
INTRODUCTION According to official data from
Given the ubiquitous nature of
Mycotoxins are toxic secondary
global institutions such as the FAO,
moulds, as well as the general
metabolites of a large number of
at least 99 countries in the world,
impossibility to prevent mycotoxin
saprophytic organisms (moulds),
which contain approximately 87%
contamination in foods feed
which, in animals and humans,
of the world population, have
materials, this topic is an integral
proliferate in contaminated food
some kind of regulation for the
part of modern livestock production.
infested with spores, conidia and/or
content of mycotoxins in food
The increase in irregularity
fragments of mycelium. Fungal toxins
for humans and/or animals.
of meteorological conditions
entering the body of animals and
associated with global climate
humans via the gut cause intoxication,
Worldwide interest in these
change has increased the problems
generally called mycotoxicosis.
problems is reflected in the
of fungal contamination at harvest
vast number of scientific and
and the production of toxins.
professional papers published on
Damage to livestock due mycotoxicosis may be
mycotoxins since the discovery of
Although it is almost impossible
significant, and are manifested
aflatoxin B1 in the early 1960’s.
to examine and measure the
in the form of direct losses due
true impact of moulds and
to mortality animals or, more
mycotoxins, the risks associated
commonly, caused indirectly
with the presence of mycotoxins
due to falling production and
is well researched and proven.
reproductive performance
(Ožegović, 1983). A specific problem is the mycotoxin residues found in different quantities in edible organs and animal products, which enter the foodchain and may cause adverse effects in humans.
3
MYCOTOXINS In chemical terms, mycotoxins represent a wide range of complex compounds with different functional groups and therefore different properties. Mycotoxins do not have sufficiently large molecules, and human and animal organisms do not produce antibodies against them and so remain permanently unprotected from their action, and in addition there is no simple method for their identification.
MOST FREQUENT MYCOTOXINS IN FOOD Common mycotoxins in foods include: Aflatoxins Ochratoxin
Fusarium toxins (zearalenone, trichothecenes) Ergot alkaloids Sterigmatocistin Patulin
Semmens (1983) state that zeolites, as mineral adsorbents, in accordance of their structure, are part of the alumina silicates’ group (SiO4 and AlO4), where the tetrahedral structure (TO4) is the basic unit. Tetrahedrons may contain various bonds, giving the zeolite structure many channels and cavities. The channel system may be
Penicillanic acid Rubratoksins Sporodezmins.
One-dimensional (unconnected parallel channels) Two-dimensional (channels connected in one plane) Three-dimensional. The diffusion rate of adsorption and ion exchange are functions of the spatial channels distribution. Every mineral is characterised by the channel opening size, so zeolites selectively retain or lose molecules depending on their dimensions.
The negative charge of the threedimensional network, which is conditioned with tetrahedral coordination, is characteristic of all the zeolites, with respective isostructural substitution of Si4+ ions with Al3+ ions. The surplus negative charge is compensated for by univalent and/or divalent cations which are located in the channels and cavities. The presented ions do not enter the zeolite tetrahedron network and, with the ion exchange reaction, they can be replaced by cations of other metals. The cation exchange capacity of zeolites is a function of silicon substitution with aluminium in the tetrahedron network. More alkali cations are required to compensate for the negative charge of elementary cells if the degree of substitution is higher. The cation exchange capacity for natural zeolite is dependent on the dimensions of the channels, ionic shape and size, the charge density and ionic valency from the electrolyte composition and is in the range of 200-300 mEq/100g in zeolites (Dixon y Weed, 1989).
4
Boyer (2000) states that clinoptilolite supplementation in animal feed leds to a significant increase in feed efficiency as well as reducing the potential of intestinal diseases (diarrhoea), and the toxic effects of surplus ammonium ions. Some researchers explain this as the clinoptilolite preference for large ions, such as NH4+, so it serves as a reservoir for ammonia. Some natural zeolites adsorb mycotoxins from feedstuffs and offer some protection from their toxic affects during digestion.
The process of mixing is an important phase in the production of premixes and feeds, in order
MEASURES FOR THE PREVENTION AND CONTROL OF FUNGI IN CORN
to attain uniformity in the basic matrix (carrier) distribution of the components so that each consumed amount of feed contains the required amount of nutrients (Filipović et
al., 1993), including toxin binders. Spoilage of animal feed means
In Serbian conditions, feed samples commonly contain zearalenone, ochratoxin A, trichothecenes (T-2, DAS) and aflatoxins. Research by Bočarov-
Stančić et al. (2000) and Jajić et al. (2010) showed that in years with good climatic conditions, between 20 and 25% of cereals were contaminated with mould and mycotoxins. Rajić y Ožegović (1990) suggested a set of measures for the prevention and control of moulds in corn, namely:
deviation from the normal quality in terms of changes of organoleptic
The selection of corn resistant to mould
characteristics, nutritional value
Seeding early varieties
and/ or hygiene of food stuffs (Šefer
Prevention of grain breakage
et al., 1997). Feed contamination with fungi causes poorer productive performance, increased metabolic disorders and diseases, and can eventually cause death. As a result, the presence of moulds in animal feed is an important criterion in evaluation of the quality of an animal feed.
Artificial grain drying Hygienic cleaning of the grain hoppers Grain aeration Tighter control measures for moisture Treating grain with propionic acid or a mixture of organic acids.
5
In intensive poultry production
MOST COMMONLY USED ADSORBENTS
adsorbents most often used to neutralise the harmful effects of mycotoxins achieve this by bonding. Adsorption therapy is one of the most important methods in preventing mycotoxicosis.
Supplementing zeolites at a rate of 0.5% in poultry feed under field conditions has achieved good results in the
Some of the adsorbents used include: Activated charcoal Hydrated sodium-aluminosilicates calcium (HSCAS) Bentonite Clay soil Various aluminosilicates or zeolites
(Adamović et al., 2003, Resanović et al., 2004).
prevention of mycotoxins. Further research on the different categories of poultry showed that zeolites can be used in amounts of 0.2% of the feed to effectively prevent the harmful effects of mycotoxicosis (Radovič et al.,
2000), which confirmed the previous results obtained in vitro.
Zeolites are classified as safe
Adding 0.5% of the commercial zeolite
or GRAS (Generally Regarded
MINAZEL in feed for laying hens
As Safe) compounds as per
contaminated with T-2 toxin (2 mg/kg in
EU 21 CFR Part 582.2729.
corn and 1.2 mg/kg in sunflower pellet) had a positive impact on increasing laying capacity and mitigated the negative effects of T-2 mycotoxicosis.
6
RESEARCH The research using MINAZEL
Zeolite (clinoptilolite)
in hens diets, supplemented
supplemented at levels of
at levels of 0, 0.2, 0.3 and
1.2% and 4% in feed had
0.5%, confirmed that the best performance was with 0.5% MINAZEL, giving increased laying, higher egg weight, better feed intakes, less feed consumption per egg, and improved FCR (Radović, 1997;
Radović et al., 2000).
a positive effect on weight The use of MINAZEL at a level of
gain, final body weight and
0.2% in broilers diets had a positive
FCR in broilers, with the best
impact on reducing mortality,
performances seen in those
achieving higher body weights and
receiving the 2% zeolite feed.
improving FCR (Palič et al., 1990; 1991;
Radovič et al., 1999; 2003; 2004). Bočarov- Stančić et al. (2000) added zeolites into meal feeds for broilers and found enhanced growth of 1.7-2.6%, and better FCR by 5.9-6.4% in the supplemented compared to the control group.
Adding MINAZEL at a level of 0.5% had a positive impact on body weight and growth of broilers and prevented the deposition of aflatoxin B1 in organs (Sinovec and Resanović, 2005; Resanović and Sinovec, 2006).
7
RESEARCH The effects of different types and levels of mineral adsorbents (MINAZEL and ‘Min-a-Zel Plus’ (MINAZEL PLUS)) on production and slaughter characteristics of broilers at 42 days were studied by Karović
(2009), Karović et al. (2010) and Radović et al. (201a; 2010c). During the fattening stage, different zeolites at different levels were used and compared to a negative control; MINAZEL at 0.5%; MINAZEL PLUS at 0.2% and MINAZEL PLUS at 0.3% inclusion. The authors concluded that the maximum weight gain was seen at 0.5% inclusion, and the percentage of inedible products was
highest in the 0.2% group.
Radović et al. (2010a) examined the impact of different levels of mineral adsorbents (MINAZEL and MINAZEL’) added to broiler feed on production. A trial was conducted with 400 broilers from one day old, of Cobb 500 breed, divided into four experimental groups. The control group (K) and experimental groups (I, II and III) were fed a complete feed of the same composition, with different levels of added
mineral adsorbent (0.5, 0.2 and 0.3% respectively). The authors showed that 0.5% supplementation gave the best feed conversion (1.716 g/g), followed by 0.3% (1.891 g/g) and 0.2% (1.978 g/g), with the poorest seen for the control group (2.161 g/g). In addition, the highest average body weights, average daily gains, and best FCR was observed for the 0.5% group. The authors concluded that broilers fed complete feeds with 0.5% clinoptilolite gave better results, and that the differences between the mid values were statistically significant (P<0.05).
8
RESEARCH Similar studies were conducted
The highest mortality was seen in
Best total weight of chilled
by RadoviÄ&#x2021; et al. (2009; 2010b),
the control group, and the lowest
carcasses was found in the 0.5%
who explored the influence of the
in the experimental group with the
supplemented group of chickens
addition of the mineral adsorbents
addition of 0.3% â&#x20AC;&#x2DC;MINAZEL PLUS.
(male 1570.0 g, female 1510.0
MINAZEL and MINAZEL PLUS to feed on the yield of broiler chickens separated by gender.
The highest average body weight of chickens were in the 0.5% group (male 2179.8 g, female 2086.3 g).
g), followed by 0.3% (male 1428.8 g, female 1371.3 g), 0.2% (male -1358.8 g,female -1303.8 g) and control (male
The research was conducted
Weight gain of chickens fed 0.3%
on 400 Cobb 500 broilers,
MINAZEL PLUS ranged between
divided into four treatment
1976.5 g (male) and 1899.3 g
The lowest yield (71%) was
groups, until they were 42
(female). The average weight of
found in female broilers in the
days of age. Dietary treatments
chickens fed 0.2% MINAZEL PLUS
0.2% group, while the highest
included a control (0%), 0.5%
was 1874.8 g (male) and 1836.0
value of 72.5% was in the same
MINAZEL, 0.2% MINAZEL PLUS
g (female). The chickens in the
treatment of male broilers.
and 0.3% MINAZEL PLUS.
control group had the lowest weights
-1265.0 g, female -1176.3).
(male 1754.5 g, female 1649.0).
9
RESEARCH Palič et al. (1990) conducted a trial using one-day old chickens, divided into three groups of 50 animals. One experimental group received T-2 toxin at a level of 1 mg/kg body weight directly into the crop, and the other groups received the same treatment, but with the addition of 0.2% MINAZEL into the feed. The group that received the MINAZEL achieved the highest average body weight (899 g) compared to the chicks that did not receive the mycotoxin adsorbent (805 g).
In a study with 100 broilers divided into four groups of 25 animals, a complete diet either without zeolite (control) or with the addition of
In a further experiment with broilers, Palič et al. (1991) zeolite supplement in doses of 0, 0.2, 0.5, and 1.0% in feed contaminated with 5.0 and 5.4 mg/kg zearalenone. It was determined that 0.2% MINAZEL gave the best results, showing the lowest mortality,
0.2%, 0.5% and 1% zeolite, Rajič et al. (1992) found that the average weight of the experimental groups, compared to the control, on the 35th and 40th day of age were significantly higher (P<0.001). FCR, relative to the control group, was 3.4% lower for the 0.2% group, 3.66% for the 0.5% group and 3.70% for the 0.1% group.
highest weight and lowest average
Based on these results, the authors
feed consumption per kg gain.
concluded that the addition of zeolite to feed for chickens had a positive impact on body weight and feed conversion.
10
RESEARCH In a dose response trial for zeolite (0, 2.5 and 5%) RajiÄ&#x2021; et al. (1992) found that chickens fed 2.5% supplemented feed had 9% higher body weights and 4-8% improved feed conversion.
Kelemen y Bogaromy (1983) fed broiler chickens with a feed containing 3% and 10% zeolite. The 3% diet had less influence on body weight than that supplemented with 10% in the final (grower) stage of feeding. Average chicken body weight on day 49 was 3.5% to 4% less in the control chickens group.
In addition, Duff et al.(1987) found that mycotoxins that cause inhibition of growth can also cause a reduction in bone strength. It is considered that the presence of even minimal amounts of OTA (> 0.5 ppm) can cause a negative effect on the broiler performance. These negative effects are already evident at the end of the first week of age, when fed contaminated feed, and chicks then lag behind in growth, which is dose dependent, but which is more pronounced in males. Exposure to contaminated feed without supplementation with a mineral adsorbent for longer periods causes a significant decrease in body weight (~12%) and increased feed conversion ratio. The results for average daily gains in broilers show that mycotoxins cause significantly negative effects on this parameter. Ayed et al. (1991) found significantly lower daily weight gains in broilers fed contaminated feeds without adsorbant supplementation.
11
RESEARCH Sukan et al. (1994) added 1% of zeolite to broiler feed which was not contaminated with mycotoxins. Results showed that body weight of chicks and daily gain were increased with zeolite, but also caused higher (poorer) feed conversion.
Similar tests were conducted by Dobeic y Amon (1994), aĂąadiendo un 1%, 2%, 4% y 6% de clinoptilolita al pienso. Clinoptilolite at 1, 2 and 4% resulted in increasing gain, higher final body weights and better feed conversion. Clinoptilolite increased the number of erythrocytes in the blood, while the 6% inclusion level led to decreased moisture in the faeces. Furthermore, the addition of 1% zeolite in feed reduced aflatoxin B1 residues by 72%, although 2% zeolite gave the same levels of residues as the control group (no aflatoxins), with gain improvements of 1.7-2.6%, and better feed utilisation of 5.9-6.4%. del pienso (5,9-6,4%). The use of zeolites (clinoptilolite) in various amounts (1, 2, 4 and 6%) showed that feeding 1, 2 and 4% had a positive effect on body weight gain and final weight of broiler chickens. The highest body weight and feed conversion efficiency were in the group of broilers fed 2% zeolite in the ration.
ZĂĄvodsky et al. (1985) fed males and females with 1% and 2% of zeolite in feed. On the 50th day of feeding, the body weight was 1803 g and 1819 g (with 1% or 2% of zeolite respectively). The body weight of chickens fed the negative control was 1873 g. Feed conversion in which the zeolite was added was 2.36 and 2.184, and without zeolite it was 2.00. Lon-Wo et al. (1987) fattened chickens with feed containing 5% of zeolite for a period of eight weeks. They determined that the fattening production results at the beginning of the trial in both groups of chickens were very similar, but at the end of trial period, feed efficiency was better and mortality lower for the broilers which received zeolite (P<0.05). Addition of 5% zeolite in the finishing feed for chickens gave significant improvements in feed conversion (P<0.05). In a second experiment, 20 geese aged 7-21 days old were fed a ration contaminated with aflatoxin B1, B2 and G1 concentrate, with and without zeolite. Zeolite addition improved conversion and carcass yield.
12
ZEOLITE Application of zeolite in feed to prevent poultry mycotoxicosis has been shown to be effective (Sinovec et al., 2002; Radović and Bogosavljević-Bosković, 2006), both in experimental (Resanović et al., 2004), and practical conditions (Palić et al., 1991).
Adding zeolite in feed contaminated with different mycotoxins reduces pathomorphological alterations in target organs (Nedeljković-Trailovi et al., 201; 2004). In addition, significant reductions in the presence of residues in edible tissues of broilers have been noted (Sinovec et al., 2002), but it should be stated that the efficiency of zeolite depends on the application and form in which it is used (Radović et al., 2000; Resanović et al., 2004).
Conclusions Increasing needs of consumers for improved food safety and quality impose constant problems in producing suitable and acceptable poultry meat and eggs.
It is assumed that different levels of mineral adsorbents added to the feed of broiler chickens have different and unequal effects on consumption and feed conversion, body weight gain, final body weights, carcass traits and meat quality as well as the health status of chickens in accordance with duration and economic performance.
Mycotoxin contamination of animal feed and resulting residues in meat and eggs are therefore an important consideration in poultry production. Because mineral adsorbents are broadly used in poultry diets, they contribute greatly in improving the quality of feedstuffs, productive performance, meat quality and carcass yield.
Tica et al. (2010) also demonstrated the impact of zeolites on the economic performance of growing broiler chickens exposed to mycotoxins. The use of mineral adsorbents in feeds and premixes can provide a solution to mycotoxicosis, showing better productive performance and economic returns to growers. However, in Serbia, the full benefits of the use of mineral absorbents can only be seen with the readiness of customers to purchase poultry meat products according to their quality.
For egg production, adsorbents can help increase egg production in laying hens, reduce mortality, improve feed conversion and prevent the occurrence of various pathological changes.
13
REFERENCES
ADAMOVIĆ, M., TOMAŠEVIĆ-ČANOVIĆ, M., MILOŠEVIĆ, S., DAKOVIĆ, A. and LEMIĆ, J. (2003) The contribution of mineral adsorbents improving production and reproductive traits to general health and quality of animal products. Biotechnology in Animal Husbandry 19(5-6): 383–395. AYED, M., DAFALLA, R., YAGI, I. and SEI, A. (1991) Effect of ochratoxin A on Lohman type chicks. Vet. Hum. Toxicology 33: 557-560. BOČAROV-STANČIĆ, A., MILOVAC, M. and GOLOŠIN, B. (2000) Detection of mycotoxins in cereals and animal feed. Proceedings of the Conference ITNMS, Belgrade, pp. 74-77. BOYER, J. (2000) Zeolite in animal nutrition. Undergraduete Seminar, http://animsci.agrenv.mcgill.ca/courses/ugradsem/00_01/Boyer_Sci.html. DIXON, J.B. and WEED, S.B. (1989) Zeolites in soils. Minerals in Soils Environments. Soil Science Society of America, pp 873-906 (Wisconsin, Academic Press). DOBEIC, M. and AMON, M. (1994) Influence of local clinoptilolite in the broiler chicken production. Proceeding of the 8 international Congress of Animal Hygiene, St. Paul. Minesota, USA, pp. 71-74. DUFF, S., BURNS, R. and DWIEVEDI, P. (1987) Skeletal changes in broiler chicks and turkey poults fed diets containing ochratoxin A. Research in Veterinary Science 43: 301-307. FILIPOVIĆ, S., FILIPOVIĆ, N. and IVIĆ, M. (1993) Testing homogeneity of powder mixtures. Žitohleb 20: 131-134. JAJIĆ, I., JURIĆ, V., GLAMOČIĆ, D. and KRSTOVIĆ, S. (2010) Occurrence of deoxynivalenol and zearalenone in maize. Contemporary agriculture 59(3-4): 227-233. KARELINA, O. (1985) Zeolites fog feeding broilers. Ptitosevodstvo 9: 26. KAROVIĆ, D. (2009) The mineral adsorbents effect on production and quality meat broilers fattening. Msc. Thesis, University of Kragujevac. KAROVIĆ, D., RADOVIĆ, V., OKANOVIĆ, Đ., DŽINIĆ, N., IKONIĆ, P., TASIĆ, T. and GUBIĆ, J. (2010) The influence of additives in food of mycotoxins adsorbents for broilers on the quality of by-products. Proceedings of the XV Conference on Biotechnology, Čačak, 15(17): 511-516. KELEMEN, G.B.K. and BOGAROMY, Z. (1983) Utilization of zeovite in the feeding of chickens. A zeovite felhasznalasa pecsenyecsirken takarmanyozasaban. Mosonmagyarovary Mesogazdagtudomanyi Kar Kozlemenyei, 25, 1/10, 79-94. LON-WO, E., PEREZ, F. and GONZALES, J.L. (1987) Inclusion of 5% zeolite (clinoptilolite) in diets for fettening chickens under commercial conditions. Cuban Journal of Agriculture 21(2): 165-169. NEDELJKOVIĆ-TRAILOVIĆ, J., JOVANOVIĆ, N. and SINOVEC, Z. (2004) Effect of exposure time and dietary ochratoxin A (OTA) level on broiler performance. Acta Veterinaria 54: 419-426. NEDELJKOVIĆ-TRAILOVIĆ, J., ŠEFER, D., SINOVEC, S., ZUROVAC-KUZMAN, O. and SINOVEC, Z. (2001) Prevention of ochratoxicoses in broilers using modified clinoptilolite. XII International congress WVPA, Cairo, pp. 377. OŽEGOVIĆ, L. (1983) Micotoxicosis of poultry. Veterinaria 33: 393-410. PALIĆ, T., PETROVIĆ, R., STANOJLOVIĆ, M. and JOVANOVIĆ, Dj. (1991) Applicability of Mycosel of poisoning chickens T-2 mycotoxin. Proceedings of Conference on „Poultry days’, Zlatibor, pp. 117-119. PALIĆ, T., VUKIĆEVIĆ, O. and RAJIĆ, I. (1990) Possibility of application of zeolites in modern livestock production. Veterinary Bulletin 44(10): 879-887. RADOVIĆ, V. (1997) The influence of zeolite in the diet of laying hens Isabrown SSL on production and egg quality. Msc. Thesis, University of Kragujevac. RADOVIĆ, V. and BOGOSAVLJEVIĆ-BOŠKOVIĆ, S. (2006) Application of natural zeolite in poultry nutrition. Natural mineral resources and possibilities of their use in agricultural production and food industry. Proceedings of the Association of Agricultural Engineers and Geoinstitut, Belgrade, pp. 121-128. RADOVIĆ, V., FILIPOVIĆ, S., OKANOVIĆ, Đ., KAROVIĆ, D. and KORMANJOŠ, Š. (2010a) The effects of mineral adsorbents on feed conversion in fattening of broilers. Proceedings of the XV Conference on biotechnology, Čačak, 15(17): 603-608. RADOVIĆ, V., FILIPOVIĆ, S., OKANOVIĆ, Đ., RISTIĆ, M., KORMANJOŠ, Š. and KAROVIĆ, D. (2010b) Effect of mineral adsorbents added to the food the broiler carcass yield. International 55th Meat Industry Conference, Tara, Book of Abstract, pp. 158-159. RADOVIĆ, V., KAROVIĆ, D., OKANOVIĆ, Đ., FILIPOVIĆ, S., GUBIĆ, J., TASIĆ, T. and IKONIĆ, P. (2010c) The influence of mineral adsorbents in addition to the results of fattening food of broilers. I Workshop, XIII International Symposium on Technology Feed for Animals, Novi Sad, pp. 268-277. RADOVIĆ, V., KAROVIĆ, D., OKANOVIĆ, Đ., FILIPOVIĆ, S. and KORMANJOŠ, Š. (2009) Effect of mineral adsorbents added to food production results in a broiler. Meat Technology 50(5-6): 271-275. RADOVIĆ, V., RAJIĆ, I. and BOGOSAVLJEVIĆ-BOŠKOVIĆ, S. (2004) Min–a–Zel Plus eating turkeys for fattening, the impact on production traits. Biotechnology in Animal Husbandry (spec.issue) 20(5-6): 259- 263. RADOVIĆ, V., RAJIĆ, I. and RADOVANOVIĆ, T. (1999) The influence of zeolite added to the feed for laying hens on the weight and thickness of shell eggs. Acta periodica tehnologica 31: 397-402. RADOVIĆ, V., RAJIĆ, I. and RADOVANOVIĆ, T. (2000) The influence of zeolite added to the feed mixture to the number of hens eggs of Hough units. Scientific Symposium on Agriculture of the Republic of Serbian with International Participation, Book of Abstract, Teslić, pp. 113. RADOVIĆ, V., RAJIĆ, I., STANIĆ, D. and NADAŽDIN, M. (2003) The effect of different phosphorus sources on growth and body weight of chickens for fattening. Biotechnology in Animal Husbandry 19(3–4): 43–48. RAJIĆ, I., KONJEVIĆ, M. and VLAHOVIĆ, M. (1992) The influence of zeolite added to the contaminated feed mixtures zearalenone (F-2) on growth and feed conversion of broilers. Biotechnology in Animal Husbandry (spec.issue) 8(5-6): 191-194. RAJIĆ, I. and OŽEGOVIĆ, L. (1990) The influence of dance on the quality of corn and proposed measures for prevention and rehabilitation. Krmiva 22(10): 214-219. RESANOVIĆ, R. and SINOVEC, Z. (2006) Effects of broiler limited feeding by aflatoxin contaminated feed on performances. 28 Mycotoxin Workshops, Bydgoszcz, pp. 56. RESANOVIĆ, R., SINOVEC, S. and SINOVEC, Z. (2004) Effect on aflatoxin B1 tissue residues by addition of modified clinoptilolite to aflatoxin B1 contaminated broiler diets. XIII International congres WPA, Florence, pp. 152-158. SEMMENS, M.J. (1983) Cation-exchange properties of natural zeolites, in: POND, W.G. & MUMPTON, F.A. (Eds) Zeo Agriculture: Use of Natural Zeolites in Agriculture and Aquaculture, pp. 45-53 (Westview Press, Boulder, Colorado). SINOVEC, Z. and RESANOVIĆ, R. (2005) Prevention and control of mycotoxicosis by using modified clinoptilolite. Proceedings of the Serbian Heritage Natural Sciences, Belgrade, 108: 147-155. SINOVEC, S., RESANOVIĆ, R., NEDELJKOVIĆ-TRAILOVIĆ, J., ŠEFER, D. and SINOVEC, Z. (2002) Modified clinoptilolite as remedy for prevention of aspergillotoxicoses in poultry. 27th World Veterinary Congress, Tunis, pp. 12-13. SUKAN, S., ERKEK, R. and ONGEN-BAYASAL, G. (1994) Effects of enzyme and zeolite supplementation to broiler diets: Civciv yjemi katki mmaddesi olarak takli konsantrasyonlarda enzim ve zeolit kutlanimi. Turkish Journal of Agriculturre and Forestry 18 (2): 141-144. ŠEFER, D., NEDELJKOVIĆ-TRAILOVIĆ, J., JOVANOVIĆ, N. and SINOVEC Z. (1997) Influence of T-2 toxin on performances and health status on broilers. ESVCN Conference, pp. 78. TALANOV, G.A., CHUPALKHINA, O.K., BRICHKO, N.V., USTENKO, V.V. and SKVORTESOV, F.F. (1994) Effect of zeolite and its products on natural resitance and productivity in finishing chickens and cattle. Problemy Vetrinarnoi Sanitari i Ekoligii 94: 15-20. TICA, N., OKANOVIĆ, Đ., ZEKIĆ, V., KAROVIĆ, D. and MILIĆ, D. (2010) The influence of the use of food with the addition of mineral adsorbents on economic performance in fattening broilers. 21st Symposium on Livestock, veterinary medicine and economics in rural development and production of safe food, Belgrade, Book of Abstract, pp. 190. VALDIVIE, M., ELIAS, A. and GONZALEZ, L.M. (1993) Saccharina in rations for broilers with zeolite, sugar and torula yeast. Cuban Jouranl of Agricultural Science 27(2): 187-191. ZAVODSKY, G., SPILITEK, M., KLECKER, S. and VODA, M. (1985) Zeoilite in mixed feeds for broilers. Zeolity v krmivarske praxi. Krmivarstvi a Služby 21(4): 78-80.
14