Effect of nano copper oxide and nano zinc oxide on mineral bioavailability, performance, and health of ruminants

Williams, A. (2021) Effect of nano copper oxide and nano zinc oxide on mineral bioavailability, performance, and health of ruminants. Doctoral thesis, Harper Adams University.

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Abstract

Ruminants are often supplemented with trace minerals to maintain health, productivity, and profitability. Trace minerals can be supplemented in an oxide form but compared to other forms available, such as sulphate, oxides have a relatively low bioavailability. For example, the bioavailability of Cu oxide is approximately 0.15 compared to Cu sulphate. Improving the bioavailability of Cu oxide could reduce the dose required to maintain animals Cu status and reduce excretion into the environment. Studies have reported an improvement in the bioavailability of trace elements when supplied as nanoparticles, and three studies were conducted to evaluate this hypothesis. The first study, conducted in lambs, compared the bioavailability of Cu and Zn oxide (nano and conventional) with Cu and Zn sulphate. Differences in Zn status were difficult to detect because the basal ration had a higher Zn concentration than predicted therefore the supplement was only a small proportion of total Zn intake. Final liver Cu concentration indicated that nano Cu oxide may have a greater bioavailability than conventional Cu oxide, but greater statistical power was required. To increase statistical power, the second study reduced the variation in Cu status between lambs using a Cu depletion, repletion technique and the number or replicates was increased. The bioavailability of nano Cu oxide was greater than conventional as indicated by the increased (P < 0.05) storage of Cu in the liver and higher (P = 0.033) whole blood SOD activity. The third study was conducted to determine the bioavailability of nano Cu oxide in the presence of antagonists (S and Mo) in dairy cows. Liver Cu concentration was increased (P = 0.042) in cows fed nano Cu oxide compared to conventional Cu oxide and this effect was particularly pronounced when there were additional antagonists in the diet. These results indicate that nano Cu oxide does have a greater bioavailability than conventional Cu oxide, but further work is required to identify a relative bioavailability value, which is between 0.23 – 0.81 compared to Cu sulphate. There are concerns over the safety of nanoparticles, but parameters measured in these three studies indicated that there was no effect on animal performance and health. Plasma GGT activity, an indicator of liver health, and haematology profile did not differ between Cu sources. This series of studies, was however, relatively short term therefore longer studies would be required to confirm this. Nanoparticles were unable to be detected in milk and blood therefore it is possible that particles are not retained in their original form in the digestive tract. Further method development work is required using SP-ICP-MS for detection of nanoparticles in biological samples

Item Type: Thesis (Doctoral)
Divisions: Veterinary Health and Animal Sciences (from 1.08.20)
Depositing User: Ms Kath Osborn
Date Deposited: 11 Jun 2021 14:26
Last Modified: 22 Jul 2021 11:29
URI: https://hau.repository.guildhe.ac.uk/id/eprint/17695

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