Assessment of drinking water and wastewater quality in dairy cattle farms and its adverse effects on host cell response in mice

Water is an essential medium for animal metabolism as well as an important cleaning medium and it must be maintained at certain quality to avoid adverse effects on the animals. According to the National Water Quality Standards, water source with a classification of Class III and less is deemed suitable for animal consumption. The chances for water quality to be substandard is as the possibility of farmers using water from a questionable water source exists. Therefore, there is an urgent need to explore the possible adverse effects in the livestock from drinking the substandard drinking water. In our best knowledge, most cattle farms in Malaysia do not practice wastewater treatment prior releasing it into water bodies such as drains, rivers and lakes and this can lead to environmental pollution and adverse health effects to the fauna in the immediate surrounding. In this study 7 cattle farms were selected and both drinking water and wastewater samples were sampled for laboratory analysis. The water samples were analysed in-situ and in the lab for 15 water quality parameters which are dissolved oxygen, pH, salinity, electrical conductivity, turbidity, biological oxygen demand, chemical oxygen demand, total suspended solid, total dissolved solid, ammoniacal nitrogen, nitrate, phosphates, total coliform, iron and magnesium content. The results were then compared with the National Water Quality Standards and the overall classification for each water sample was decided. Then, the water classification was further narrowed to three categories for the purpose of this study, namely, good category (Class I and Class II), moderate category (Class III) and unsatisfactory category (Class IV and Class V). The results for drinking water were as follows; 1(14.29%) Class II, 2 (28.57%) Class III, 2 (28.57%) Class IV and 2 (28.57%) Class V. Meanwhile, all the wastewater samples in this study were categorized as Class V. A total of 35 female mice were divided into 5 groups; Group 1, 2, 3, 4 and 5 with 7 mice in each group. All the mice were gavage fed with 0.25 ml of water samples three times daily for a period of 30 days. Group 1 was fed with sterile deionized distilled water as the negative control, Group 2 was fed with the water sample from the good category, Group 3 was fed with the water sample from moderate category and Group 4 was fed with the water sample from unsatisfactory category. Meanwhile, Group 5 was fed with one of the wastewater samples. The mice were observed at regular intervals and any mice that require humane end-points were euthanized and blood was collected through cardiac puncture before post-mortem examination and preservation of visceral organs and the brain. At the end of the 30 days, all surviving mice were sacrificed and blood, visceral organs and the brain was preserved for serological and histological examinations. All treatment groups showed weight loss in comparison to the control group with the group treated with the wastewater showed most significant weight loss (p<0.05). Mice in groups 1, 2 and 3 did not show any significant clinical signs changes throughout the experimental period. In this experiment, 57%(n=4) of the mice from group 4 exhibited moderate emaciation and mild ruffled fur at the end of the experiment while all the mice (n=7) from group 5 exhibited clinical signs of severe ruffled fur, dehydration and severe emaciation and were euthanized to minimize pain. No significant gross lesions were observed in mice from groups 1, 2 and 3. Only 57% (n=4) of the mice from group 4 showed signs of moderate dehydration while all the mice from group 5 showed signs of severe dehydration. 28.5% (n=2) of the mice from group 2 and 14.2% (n=1) of the mice from group 4 showed subcutaneous abcesses. Several coliform bacteria were isolated and identified from the abcesses. Only mice from Group 5 showed significant decrease (p<0.05) in the serum estrogen levels in comparison to the control while no significant changes were observed in treatment groups in comparison to the control group for the serum progesterone levels. In terms serum Ig G concentrations, only the wastewater treatment group showed significant elevation (p<0.05) in comparison to the control group. The treatment groups 3, 4 and 5 showed significant elevation (p<0.05) in comparison to the control group in serum Ig M concentrations. The treatment groups 4 and 5 showed significant elevation (p<0.05) in serum Il-12 concentrations in comparison to the control group. Groups 3 and 4 showed significant elevation (p<0.05) in serum Hp concentrations in comparison to the control group while groups 3, 4 and 5 showed significant elevation (p<0.05) in SAA concentrations in comparison to the control group. Histopathological analysis revealed that both the kidneys and the livers from the mice in group 3 showed moderate inflammation and degeneration cellular changes. Severe inflammation and degeneration were observed in both the kidneys and livers in mice from groups 4 and 5 while moderate inflammation were observed in uterus and ovaries of mice from groups 4 and 5. At the same time, mild presence of inflammatory cells and oedema was observed in groups 3, 4 and 5. In conclusion, this study had proven that the drinking water provided for cattle consumption in most of the cattle farms are subpar as per the requirement set by the National Water Quality Standards. At the same time, due to a lack of wastewater treatment prior to its release to the environment, the quality of the wastewater is very poor and can become a source of pollution especially in cases where the farm is located nearby raw drinking water source areas. Based on the clinicopathological and serological symptoms exhibited by the mice in the treatment groups fed different qualities of drink water obtained from the dairy cattle farms, there is a high risk that there would be a negative impact in terms of production, reproduction and health from long term consumption of drinking water with subpar quality. Therefore, constant evaluation is required to ensure that the drinking water provided to the cattle in the dairy cattle farms are up to the standard for their consumption and the wastewater in the farms should be treated and evaluated before being released to the environment to avoid pollution.

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