The levels of vitamins for poultry have changed a little over the last 40 years; however, the modern broiler has improved drastically its performance during the same period. Furthermore, an optimum level of vitamins is crucial under high stress condition to allow the birds achieve good performance and adequate health status. In this context, aflatoxin contamination of foods and livestock feeds became a great issue being a challenge for broilers. In poultry production, this kind of contamination in livestock feeds often results in poor performance, high mortality rates, and a greater susceptibility to diseases (Jones et al., 1982; Huff et al., 1986). Several strategies for the reduction or inactivation of aflatoxins have been previously reviewed and include diverse physical, chemical, and biological methods (Phillips et al., 1994, 2002; Phillips, 1999). The increase in supplementation of certain vitamins has positive effects on broiler production. For this reason, the major objective of this trial was to evaluate the effects of two vitamin levels in broilers experimentally challenged by aflatoxin on carcass yield.
MATERIAL AND METHODS
A total of 1,800 day-old Cobb 500 broiler chicks were obtained from a commercial hatchery. The chicks were arranged in a completely randomized design with eight dietary treatments. There were 225 chicks per treatment, each treatment had 15 replication having 15 chicks each in a factorial design (2 x 2 x 2) with two different vitamin levels (low and optimal); two aflatoxins levels (0 and 0.5 ppm) and two levels of mycotoxin binders (0 and 10 kg/ton). Each pen contained old litter, one tube feeder, and a nipple drinker line. Additionally, the experimental house heating was accomplished by forced air furnaces, and cooling was accomplished by negative pressure ventilation using two 48 inch fans pulling air through cool cell pads. Broilers received lighting program as recommend by management guide. All diets were primarily composed of corn and soybean meal and were fed in mash form. At 44 d of age, two broilers of each pen were weighed separately and processed to determine carcass characterisitcs (carcass yield, breast and legs relative weight). Data were analyzed as a 2 x 2 x 2 factorial by analysis of variance using the General Linear Models procedure of SAS (SAS Institute, 2000). All statements of significance are based on the 0.05 level of probability.
RESULTS AND DISCUSSION
There was no interaction between the factors studied and the presence of aflatoxin or binder did not affect carcass characteristics (Table 1). However, through the contrast analyze birds fed OVN diets had significantly higher percentage of carcass yield when compared to birds fed low levels of vitamins (Table 2). According to Santurio (2000) when some vitamins are deficient in the diets birds became more susceptible to aflatoxin resulting in poor performance. In the present work, the result indicates that an optimum level of vitamins in the diet was essential to improve carcass yield.
Table 1. Carcass of broilers fed different levels of vitamins with or without aflatoxin and binder in the diet
Table 2. Contrast between the different levels of vitamins on carcass yield in broilers
Supplemetation of vitamins in the diets can improve carcass yield in broilers.
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