Feed & Additive Magazine Issue 3 April 2021

ISSUE FOCUS 38 FEED & ADDITIVE MAGAZINE April 2021 benefits. The use of high levels of copper may func- tion as a bacteriostat in the hindgut – reducing pop- ulations of pathogenic bacteria such as clostridium and Salmonella. Research on the topic shows a drop in total anaerobe bacteria and coliform populations following Copper use. It also may play a role in im- proving the amount of nutrients available for animals by limiting microbial degradation of nutrients. HOW MUCH COPPER IS ENOUGH? CONSIDERING THE ADDITIVE EFFECT IN THE ANIMAL? Where legislative maximum limits on Copper level do not apply, the extra-nutritional benefits can be im- plemented. But how much Copper is needed in the diet to optimise gut health? Researchers examined what level of Copper is needed to reduce the bacterial populations in contaminat- ed petri dishes. Copper was added to the agar solution at varying concentrations, at 100 ppm, 150ppm, 200ppm, 400ppm and 600ppm. It is worth noting that due to the concentration effect along the GIT, the ‘supplemented in feed’ equivalence is 10ppm, 125ppm, 150ppm and 250ppm respectively, as per Fig.2. The group found that when 100ppm copper was added, the number of bacte- ria colonies remained high, which represents 10 ppm in feed, representing the nutritional requirement. It wasn’t until 400ppm copper was added that signif- icant growth inhibition occurred (150ppm in feed equivalence), while adding 600ppm meant that none of the four grew (250ppm in feed). IMPLICATIONS FROM HIGH-LEVEL COPPER INCLUSION A trial examined the influence of adding 150ppm hydroxy Copper to the diets of growing pigs and tracked the concentration of microbial protein. A group of pigs received one of two diets, and then switched to the other diet for the second trial period. Diets included two levels of DDGS (0 or 45%) to pro- vide varying protein levels, and two levels of hydroxy Figure 3 – Results from high copper inclusion during grow-finish period. Figure 2 – Relationship among copper levels added to the diet, copper in the lower GIT and control of pathogenic bacteria colonies.