Limitations of zinc oxide and copper sulphate in animal production

Problems related to the use of zinc oxide and copper sulphate in animal production

Zinc oxide (ZnO) is an inorganic compound that is used as an additive included in the feeds to control bacteria at an intestinal level and, particularly, to prevent post-weaning diarrhea in piglets (EMA 2017). Copper sulphate (Cu2SO4) is an insoluble salt that is used for its bacteriostatic and fungistatic properties and works as a growth promoter and preventative for intestinal infections (Saraiva et al. 2020). These compounds have several disadvantages, such as they are excreted in the environment, where they accumulate and can contaminate underground and surface water (EFSA 2012; EMA 2017). They also cause the development of microbial resistances (EMA 2017; FEEDAP 2016; Johanns et al. 2019; Saraiva et al. 2020), a situation that is concerning for the veterinary and human medicine sector, as it may lead to a lack of effective products against infections. In the case of zinc oxide, the development of microbial resistances is truly concerning because it is correlated with a decrease in the sensitivity to antibiotics (Johanns et al. 2019).


For these reasons, there is a growing global trend towards reducing the use of these two compounds which aims to prevent environmental contamination and the development of microbial resistances.

Trend towards reducing the use of zinc oxide and copper sulfate and limitations at the legal level

Since 2017, European authorities have considered the limitation of zinc oxide, particularly in pig farms. As a results, the European Union has established that the benefits derived from the use of this compound do not outweigh the risks and that the use of zinc oxide in pig diets is a negative practice (El-Sayed et al. 2019). For that matter, veterinary products containing zinc oxide will be banned from commercialization within the European Union since June 26, 2022 (EMA 2017) and this compound will only be allowed to be included in the feed at a maximum of 150 ppm, a much lower dose than the 2500 ppm used nowadays, so that this compound will no longer be used to obtain a pharmacological effect.

The European Union limits the use of copper sulphate in compound feeds for the different species (pigs, ruminants, aquaculture, among others) (FEEDAP 2016), which aims to slow down the development of new microbial resistances and reduce this compound’s negative impact on the environment. Besides, it recommends to analyze copper residues in meat and other animal products, as well as in agricultural areas to monitor the development of microbial resistances (FEEDAP 2016).

Table 1. Maximum copper (Cu) content allowed in compound feed (European Commission 2018)


In addition to limiting the imports to the European Union, the growing trend towards reducing zinc oxide and copper content in the feeds is followed by other countries such as Canada, where the Canadian Food Inspection Agency (CFIA) has launched a public consultation to receive proposals and make the regulations stricter (CFIA 2021b, 2021a).

Available alternatives

Global Vet’s Lab recommends the use of alternatives to zinc oxide and copper sulphate in the feeds which do not have a negative impact on the environment and to not lead to microbial resistances. These are natural tools that are safe for the environment and can be included in the diets at low doses.

  • Intestinal conditioner pronutrients, active molecules from plant extracts that enhance the physiological functions of the enterocytes. Pronutrient inclusion in the diets intended for animal feeding helps to enhance epithelial natural resistance against digestive infections and nutrient absorption (Pie, Tesouro, and Rosemberg 2018). They were proved effective to replace zinc oxide in post-weaning piglets in multiple field trials.
  • Additives that combine the cimenol ring, an aromatic antimicrobial compound from plant extracts, with citric acid (Borrell 1990): they effectively control the presence of pathogens in the feed and in the digestive tract and are safe for the beneficial flora (Anillo cimenol, la solución natural para la prevención de la enteritis necrótica en broiler 2020).

The efficacy of these two options has been broadly studied and they have a positive impact on performance in the farms.

How can Global Vet’s Lab help you?

In Global Vet’s Lab, we offer the feed formulation and analysis service to optimize feed composition and adjust it to the requirements of the local regulations. We also formulate diets to produce in a natural and safe way, and we recommend the best additives to replace products based on zinc oxide of copper sulphate. To use these services, please contact us through our webpage or email at


  • “Anillo Cimenol, La Solución Natural Para La Prevención de La Enteritis Necrótica En Broiler.” 2020. Veterinaria Digital. Technonews.
  • Borrell, Jaime. 1990. “Metabolitos Fúngicos En Los Alimentos.” Real Academia de Ciencias Veterinarias de España (RACVE).
  • CFIA. 2021a. “Canada Gazette, Part I, Volume 155, Number 24: Feeds Regulations, 2022.” Canada Gazette.
  • ———. 2021b. “Feed Regulatory Modernization.” Update September.
  • EFSA. 2012. Scientific Opinion on Safety and Efficacy of Zinc Compounds (E6) as Feed Additive for All Animal Species: Zinc Oxide.
  • El-Sayed, M. E. et al. 2019. “Pathogenicity, Genetic Typing, and Antibiotic Sensitivity of Vibrio Alginolyticus Isolated from Oreochromis Niloticus and Tilapia Zillii.” Revue de Medecine Veterinaire 170(4–6): 80–86.
  • EMA. 2017. “Zinc Oxide – European Medicines Agency.” Zinc Oxide, CVMP opinion.
  • European Commission. 2018. “Commission Implementing Regulation (EU) 2018/1039 of 23 July 2018.” Official Journal of the European Union 61(1334): 3–24.
  • FEEDAP. 2016. “Revision of the Currently Authorised Maximum Copper Content in Complete Feed.” EFSA Journal 14(8).
  • Johanns, Vanessa C. et al. 2019. “Effects of a Four-Week High-Dosage Zinc Oxide Supplemented Diet on Commensal Escherichia Coli of Weaned Pigs.” Frontiers in Microbiology 10(November).
  • Pie, Julia, Anna Tesouro, and Manuel Efrain Rosemberg. 2018. “Use of Alquernat Nebsui (Botanical Product) as an Alternative to Antibiotic Growth Promoter in Broilers.” In Poultry Science Association (PSA) 107th Annual Meeting Abstracts, San Antonio (TX, USA), 105.
  • Saraiva, M. M.S. et al. 2020. “Chemical Treatment of Poultry Litter Affects the Conjugation of Plasmid-Mediated Extended-Spectrum Beta-Lactamase Resistance Genes in E. Coli.” Journal of Applied Poultry Research 29(1): 197–203.

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