Assefa, Fassil (PhD)Mesfin, Rehrahie2019-04-112023-11-042019-04-112023-11-042/3/2018http://etd.aau.edu.et/handle/123456789/17847The production of wholesome milk is controlled by the quality and safety of feed supply. Aflatoxins and heavy metals are some of the major factors that affect the quality of feeds and water sources that are transferred and eventually get bio-accumulated in livestock species and humans via meat, milk and milk products. Monitoring dairy production inputs using technical tools and gathering appropriate information on perception, experience and indigenous knowledge of stake holders along the feed and milk chains are relevant in assessing how processing, storage and distribution of feeds and water sources to ensure safety of milk and milk products. The objective of this study was to determine aflatoxin B1 (AFB1) in feeds and aflatoxin M1 (AFM1) in milk and heavy metals cadmium (Cd), lead (Pb), arsenic (As) and chromium (Cr) in feeds, water, and milk samples from West Shoa, East Shoa and Hawassa, Ethiopia. A total of 205 samples consisting of 115 concentrate feeds, 45 roughage feeds and 45milk samples were collected for the detection and quantification of aflatoxin using Enzyme-linked Immunosorbent Assay (ELISA). A total of 90 samples (30 feeds, 30 water and 30 milk) were collected for determination of heavy metals using Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS). Stakeholders’ perception and experience of handling feeds and water sources were evaluated by interviewing peri-urban farmers, feed processors, feed retailers and urban dairy producers using semi-structured questionnaires and field observations. The results showed half of the feed samples (81) were free from aflatoxin, and the remaining (79 samples) were within the EU standard of 5μg/kg and the USA standard of 20μg/kg. The pattern of afltoxin contamination showed that concentrate feeds were more contaminated (7.67 ± 0.80 μg/kg) than roughage feeds (0.41 ± 0.14 μg/kg); hay (0.72 ± 0.25 μg/kg) was more contaminated than straw (0.05 ± 0.05 μg/kg) and oilseed cake based concentrate feeds were more contaminated (13.09 ± 1.12 μg/kg) than concentrate feeds without oilseed cake (2.78 ± 0.66 μg/kg). The average AFB1 of feeds in Bishoftu (9.76μg/kg) was significantly higher (p<0.05) than the sampling sites in Holetta (6.33μg/kg) and Hawassa (1.19μg/kg). The AFB1 of feeds handled by dairy producers was significantly higher (p<0.05) (9.35 ± 1.04μg/kg) than feed retailers (6.91 ± 1.09 μg/kg) and 2 feed manufacturers (7.50 ± 1.43 μg/kg). The AFM1 of milk was in a range and average of 0– 0.146 μg/L and 0.054 μg/L respectively of which 29% of the milk samples did not contain aflatoxin, and 58% of them had AFM1 level within the EU permitted limit of 0.05μg/L and 42% of the samples were less than the U.S.A. recommended limit of 0.5 μg/L. The AFB1and AFM1 levels of milk samples collected from the study locations were in the order of Hawassa < Holetta < Bishoftu. With regards to heavy metals, the data showed that concentrations of heavy metals in teff straw in Holetta and Bishoftu were 1543.54 ± 318.70 μg/kg and 1486.92 ± 279.73 μg/kg, respectively. The overall concentration of heavy metals in teff straw was in the order of Cr > As > Pb > Cd. The water samples taken from Mojo areas (Eastern Shoa) showed the highest of heavy metals (43.64 μg/L - 86.89 μg/L) with very high concentration of Cr (300.56 μg/L). In general, the average concentration of heavy metals in livestock water in Eastern shoa (Akaki to Mojo) (28.08 ± 7.02 μg/L) was significantly higher (p<0.05) than the levels of heavy metals in water collected from Western Shoa (Holetta/Welmera) (1.96 ± 0.28 μg/L) and the levels of the heavy metals was in the order of Cr > As > Pb > Cd. With the exception of pH of water from Mojo Lake (10.37) and Gelan dye factory (8.9), the rest of the water samples collected from Bishoftu and Holetta areas were within the legal pH limit of 6.5-8.5 for livestock drinking. The overall concentration of heavy metals in cow milk samples was in the order of Cr > Cd > Pb > As. The concentrations of Cd and As in milk were within the permissible limits. However, 60% and 73% of the milk samples from Holetta and Bishoftu respectively for Pb and, all the milk samples in both study locations for Cr were above the permissible limits indicating poor quality of milk due to environmental pollution. The data from the interview of stakeholders showed that 91% of the farmers sometimes encountered mold formation in roughage feeds due to lack of good harvesting and stacking practices. Most of the farmers admitted to feeding light moldy feeds to their livestock by diluting with uncontaminated ones. Most of the respondents (67%) used extreme moldy feeds for firewood; and 33% of the interviewees damped the extreme moldy feeds into landfills. Farmers recognized two causes of water contaminants associated with health and production problems in livestock. Accordingly farmers from Eastern Shoa (100%) were aware of the effect of industrial effluent as the most important hazard for dairy production; whereas 66% of the farmers from Eastern Shoa and 34% of the respondents from Western shoa identified leech problems in water bodies in dry season. Farmers also had indigenous knowledge to tackle the leech problem in that 69% of the farmers used bucket for selectively scooping water 3 from the water body to exclude the leech from being consumed by animals; whereas 50% of the respondents treated animals with chopped tobacco and onion. The majority of the feed processors (64%), feed retailers (82%) and dairy producers (56%) reported that they did not use palate for placing their concentrate feeds implying that there is probability of mold contamination in times of prolonged storage. Among the respondents, 88% of feed processors, all feed retailers and most (96%) of the dairy producers recognized that wheat bran was the most mold susceptible feed ingredient. Majority of the feed processors (67%), feed retailers (73%) and dairy producers (58%) stored their concentrate feeds for a short period of about 1 month. Majority of the feed processors (74%), feed retailers (87%) and most dairy producers (91%) did not encounter mold formation in their concentrate feed because of the small amount of concentrate feed they hold and shorter storage time. To overcome mold formation in concentrate feeds, 64% of the feed processors gave enough space between stored feed and the wall. Further research needs to be undertaken along the feed and milk production and distribution chains using other techniques such as HPLC, GC and multi-mycotoxin assay using LC-MS-MS taking into account different storage conditions such as use of palate, ventilation, and duration of feed storage on aflatoxin. The effect of mold growth in feeds on nutrient composition needs to be investigated. There is also a need for further investigation on heavy metals from soils and fodder feed samples grown in similar study locations.enArsenicCadmiumDairy ProducersConcentrate FeedHayStorage TimeMycotoxinsThesis