Zinc and vitamin E are vital antioxidants that protect the gut and support broiler growth and health during heat stress conditions. The biggest wins are reached by supplying them during the early days post-hatch. Now, research shows that more is not always better.
High feed prices alone are a huge challenge to tackle, but when poultry producers are faced with added challenges, such as heat stress, it puts even more pressure on controlling feed efficiency, animal performance and farm profitability. Gut health plays an important role in making birds more resilient, healthy and on target during all the challenges they face, including heat stress.
The sooner the gut maturation is positively modulated, the bigger wins can be achieved. Early intervention is key because the chick’s gut development is developing fast during early life. In the first 3 days after hatch, the absorptive nutrient area of the intestines increases by 70% (increase of villi length). This is essential because the chick needs to adapt fast from a diet based on lipids (yolk lipids) to a solid carb/protein-based diet. Gut development is complete by 10 days and the mature gut microbiome is established around 17 days.
Zinc and vitamin E
Over the years, the industry has gained a lot more insights on how to determine and measure ‘intestinal health’, and how to positively influence it through nutrition and certain feed additives such as zinc and vitamin E, both of which are vital antioxidants that protect the gut through different modes of actions.
But not all zinc sources available on the market are the same and therefore do not perform the same. The type of zinc used in poultry diets can therefore influence the optimum level of both zinc and vitamin E. Although responses to dietary zinc and vitamin E have been investigated at different environmental temperatures, to the best of our knowledge, interactions of different zinc sources and vitamin E levels have not been investigated under heat stress conditions in broilers.
A study by De Grande et al (2021), published in the Journal of Animal Physiology and Animal Nutrition, considered different levels of vitamin E in combination with different sources of zinc. The trial looked at 2 sources of zinc, 60 mg/kg of zinc as ZnSO4 or 60 mg/kg of zinc as zinc amino acid complexes* (hereafter called ZnAA), combined with 2 levels of vitamin E (50 or 100 IU/kg). Performance was measured from day 0-36. From day 28 until day 36 (finisher period), all birds were subjected to chronic cyclic high temperatures (32°C ± 2°C and relative humidity 55-65% for 6 hours daily).
More is not always better
Preparing the bird
Performance and resilience against heat stress can be positively influenced via supplementation of zinc as in the form of ZnAA used in this trial, and a vitamin E level of 50 IU/ kg early in life when the gut and its microbiome are being developed. Providing zinc in this form positively influences gut and microbiome development and hence promotes growth, and more importantly, prepares the bird for future challenges such as heat stress while retaining breast meat quality and yield when heat stress occurs. Interestingly, under the conditions of this study, positive effects on performance did not occur when vitamin E was supplemented at 100 IU/kg in feed, providing an economic benefit.
*Zinpro Availa Zn, part of the Zinpro Performance Minerals range.