Agricultural Sciences

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Browsing Agricultural Sciences by Subject "Aflatoxins"

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    Effect od supplemental dietary vitamin A on Aflatoxin B1 Toxicosis in growing Broilers
    (2015-02-26) Chibanga, Felix Joseph
    Aflatoxin B1 negatively affects broiler performance and is also a public health hazard as it has been associated with cancer in humans. Several methods have been suggested for minimizing effects of aflatoxin B1 contamination including use of anti-oxidizing agents such as vitamin A. This study was conducted to evaluate the effects of supplementing different levels of vitamin A on the performance of broiler chickens fed on diets contaminated with aflatoxin B1 at 35μg/kg of the feed diets for 42 days. The study was designed as a Completely Randomized Design in which 150 Ross Breeder’s Broiler Chicks were randomly allocated to five (5) dietary treatments with each treatment being replicated 3 times. Standard broiler chicken starter, grower and finisher rations were used as controls. In the starter phase, contamination of diets with aflatoxin B1 significantly (P ≤ 0.05) reduced feed intake, bodyweight gains and feed conversion ratios. However, this was not the case in the grower and finisher phases, where only bodyweight gains and feed conversion ratios were reduced by aflatoxin B1 contamination. This also affected final body weights and dressing out percentages of broiler chickens, where those fed on contaminated diets performed poorly compared to those on control diets. It was also noted that performance of chickens improved significantly with increasing levels of vitamin A supplementation in aflatoxin B1-contaminated diets. The toxic effects of aflatoxin B1 on feed intake of broilers were ameliorated by dietary supplementation of vitamin A at 6000 IU/kg and above. However, amelioration of the deleterious effects of aflatoxin B1 on bodyweight gains and feed conversion ratios of broilers was achieved when vitamin A was supplemented in the diets at 3000 IU/kg. Levels of aflatoxin B1 contamination used in the current study did not cause any death. Furthermore, feeding aflatoxin B1 contaminated diets significantly decreased serum concentrations of total protein, albumin, triglyceride and cholesterol. Feeding aflatoxin B1-contaminated diets significantly increased concentrations of liver functional enzymes (alkaline phosphatase, aspartate aminotransferase and alanine aminotransaminase) in the blood. This was an indication that increasing the levels of vitamin A supplementation reduced the negative effects of aflatoxin B1 contamination on protein and lipid metabolism in broiler chickens. It was thus, concluded that supplementing increasing levels of vitamin A to aflatoxin B1-contaminated diets results in reduced expression of toxic effects in broiler chickens.
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    Modeling pre-harvest aflatoxin incidence in groundnut (arachis hypogaea l.) using selected soil properties and ambient temperature
    (The University of Zambia, 2020) Chalwe, Hendrix M.
    Aflatoxin contamination of groundnut (Arachis hypogaea L.) and its products is a worldwide food safety concern. Contamination of kernels during crop growth is associated with adverse soil factors and weather conditions. Therefore, good agricultural practices are an important strategy to minimize the pre-harvest aflatoxin contamination risk in groundnut. The main objective of this study was to formulate regression models to predict pre-harvest aflatoxin contamination risk in groundnut using selected soil properties and ambient temperature. Field experiments were conducted in Lusaka and Chongwe districts of Zambia to evaluate the effects of soil amendments, namely, gypsum (15.6 % soluble calcium) and compost on pre-harvest aflatoxin incidence in groundnut. Additionally, the effects of soil moisture content and soil temperature during groundnut pod development stage on aflatoxin concentration were evaluated. The data generated from these experiments were analysed using appropriate tests at 5 % level of significance. Treatment effects were evaluated using the one or two-way ANOVA test as appropriate. The Tukey test was used to separate significantly different treatment means. Pearson correlation analysis was performed on the data to evaluate relationships between continuous variables. Simple and multiple linear regression analysis was performed on significantly correlated variables. All these tests were performed using the R-statistical software. Results showed that higher levels of compost were associated with lower aflatoxin contamination. The gypsum amendment did not have a significant effect on aflatoxin contamination of groundnut kernels. Further, regardless of the treatments applied, ambient temperature and soil temperature were positively correlated with aflatoxin contamination whereas soil moisture content was negatively correlated. Simple linear regression models gave R2 values of 0.30 for maximum ambient temperature, 0.24 for soil temperature and 0.38 for soil moisture content. Combining soil moisture content and soil temperature in a multivariate regression model explained 54 % of the variation in aflatoxin contamination. Therefore, soil moisture and soil temperature can be used to predict aflatoxin contamination risk in groundnut. The two predictive variables, soil moisture and soil temperature, can be manipulated through agronomic practices to reduce the risk of pre-harvest aflatoxin contamination in groundnut.