Tese
Amostragem de grãos em silos para análise de micotoxinas e impacto micotoxicológico e nutricional de híbridos de milho no custo da ração de frangos
Fecha
2018-02-16Autor
Mallmann, Adriano Olnei
Institución
Resumen
Cereals stored in silos can be contaminated by mycotoxins, which are distributed
heterogeneously in the grain mass. Thus, they require representative sampling in order to
minimize the analytical error. Higher requirements for maize and wheat quality have arisen
with new demands and research results. Around 70% of poultry and pork production costs are
composed of feed wich maize have the largest percent of inclusion in the diet. For safe diet
formulation, adequately nutritional requirements for animals are necessary, and for this it is
important to consider the mycotoxins risks and the chemical and energetic composition of the
ingredients. The objective of the first study was to compare mycotoxin detection analysis
in stored maize and wheat using two sampling processes and in the second study was
to evaluate the mycotoxicological and nutritional variables of maize hybrids with
different characteristics that influence the broiler chickens feed costs. In the first study,
a pneumatic probe was introduced in the centre and at the four central points of each
quadrant, from the top to the bottom of the silo (12 m). For sampling process A, this
was divided into three samples (upper third, middle third and lower third of the silo
height). No sample subdivision took place for sampling process B. Aflatoxins (AFLA),
fumonisins (FUM), zearalenone (ZEA) were detected in the maize samples, with a
difference in the mean concentration of the silos. In wheat, deoxynivalenol (DON) and
ZEA were detected, with no difference in the mean concentration in the silos. The two
sampling processes provide results of analyzes with the same variability in maize and
although process A has lower variability for DON in wheat, the two processes provide
samples with the same representativity considering the silo as a whole, supporting the
decision making in the maize purchase, sale and destination of the grains. In the
second study, evaluating 26 genetically modified maize hybrids of 2016 and 2017
winter crops, with different germplasm, endosperm grain texture and cycle length, the
prevalence of FUM, AFLA, ZEA and DON was 90, 17, 33 and 0%, with means of 3067,
1, 38 and 0 μg/kg in the two years, respectively. The mean apparent metabolizable
energy corrected for nitrogen balance (AMEn) and crude protein (CP) was 3264
kcal/kg and 8.02%, respectively, and differed in the two years. The estimated feed for
broilers chickens cost was influenced by FUM, PB, AMEn in the two years. Hybrids
with Viptera technology show lower concentration per FUM and lower feed cost. Early
cycle hybrids have lower concentrations of FUM, higher percentages of CP and
digestible amino acids, and lower feed costs.