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Strategies and efficacy of phytase supplementation and its interaction with pharmaceutical zinc oxide in newly weaned pigs

Mansbridge, S.C. (2017) Strategies and efficacy of phytase supplementation and its interaction with pharmaceutical zinc oxide in newly weaned pigs. Doctoral thesis, Harper Adams University.

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Abstract

Feeding the World sustainably in the 21 st century and beyond is perhaps one of the biggest challenges mankind has faced. Plant based pig feeds contain significant quantities of ph osp horus , essential for animal health and performance, but which is locked - up in phytic acid and associated phytate salt s ( only around 30 % digestible ) . Since the 1990’s, phytase enzymes have been added to non - ruminant feeds to enhance phytate digestibility . Recent e videnc e suggests that feeding super doses of phytase increases growth performance beyond that a ttributable to phosphorus release alone. In the UK, therapeutic levels of ZnO are often prescribed to prevent and treat post - weaning diarrhoea in newly weaned pigs, th ough some evidence suggests zinc may reduce the phosphorus releasing efficacy of phytase. Improving the efficiency of pig production , reducing environmental pollution and maximising the use of n on - renewable resources may help contribute to a sustainable an d secure global food chain. The objective of this study was to evaluate the optimal strategy for using phytase in weaner pig diets, in conjunction with pharmaceutical ZnO . Four live pig experiments were conducted to quantify the growth response to increasi ng dietary phosphorus, identify ‘extra phosphoric’ effects associated with phytase super dosing and to evaluate this response in ZnO medicated feed . Resulting r ecommendations are to super dose phytase (2000 - 8000 FTU/ kg ) for two weeks post - weaning; reduci ng to 100 0 FTU/kg in the third week post - weaning to fa cilitate bone mineralisation. I n this study, seemingly healthy pigs fed pharmaceutical ZnO at high levels (3100 mg/kg feed) showed reduced growth performance , possibly due to interactions between zinc and phosphorus . Further research into reducing levels of pharmaceutical ZnO in feed and the use of ZnO nanoparticles could help overcome these risks. There may also be justification for a high er inclusion of dietary digestible phosphorus in ZnO medicated d iets post - weaning , especially in low phosphorus diets .

Item Type: Thesis (Doctoral)
Divisions: Animal Production, Welfare and Veterinary Sciences
Depositing User: Ms Kath Osborn
Date Deposited: 21 Aug 2018 15:49
Last Modified: 22 Aug 2018 13:24
URI: http://hau.collections.crest.ac.uk/id/eprint/17317

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