Effect of the removal of pharmacological doses of zinc oxide from the post-weaning diets of outdoor bred newly weaned piglets.

05 Jan 2021


By Annie Williams

Take home message: A high fibre, low protein diet is unable to offset performance loss caused by removal of pharmacological doses of zinc oxide in piglet diets.

Zinc oxide at pharmacological doses has been used in piglet diets to reduce the effects of enteric disorders and prevent decreased growth rates post-weaning. Growing concerns over damage to the environment caused by zinc oxide (ZnO) has led to incoming controls over its use. Other options to help enhance growth rates post-weaning are being investigated and low protein and high fibre diets have been suggested as a potential option.

This study was designed to assess the effect of low protein and high fibre diets and also considered the quantity of straw consumed and crude protein digestibility. 1760 commercial outdoor-bred piglets were randomly allocated to one of four treatments in a 2 x 2 factorial experiment from weaning at 28 days of age, balanced for litter origin and sex. Pigs were fed either an ‘XP’ diet or standard ‘Ultra’ diet with or without the inclusion of 3100 mg ZnO/kg. The ‘XP’ diet was lower in protein and higher in fibre than the ‘Ultra’ diet by including 4% wheat bran. The dietary treatments were fed from day 0 to 11 (phase 1) and all pigs were fed the same diet from days 11-17 (phase 2) and days 17-31 (phase 3).

Pigs fed diets including 3100 mg/kg ZnO had a significantly greater average daily live weight gain and average daily feed intake, other performance parameters measured remained unchanged. Pigs fed diets lower in protein and higher in fibre did not have any performance improvement. There were also no differences between pigs allocated to different treatments for straw consumption or crude protein digestibility. All pigs consumed a significant amount of straw and the effect of this on nutrient digestibility and animal performance requires further research. To conclude, a higher fibre, lower protein diet was unable to offset performance loss when pharmacological doses of ZnO were removed from the diet. Therefore, the contribution of this dietary change in replacing ZnO considering the impending ban on the use of pharmacological doses of ZnO in piglet diets may be limited.

The study was conducted by Annie Metcalfe, studying Agriculture at Harper Adams University, she said “It has been great to have been nominated and receive highly commended for my thesis and I look forward to seeing the other entries in the fledging bytes series”. Annie has recently started a job with Primary Diets and hopes to develop a career in monogastric nutrition and continue to progress in the animal nutrition industry.

Annie Williams, Agrimin Ltd (formerly PhD student at Harper Adams University)

Annie has been a member of the BSAS Early Careers Council for 3 years and has just completed her PhD at Harper Adams University studying mineral nutrition in ruminants. Annie is now working as Export Manager and Technical Support at Agrimin Ltd.