Hello, I am Charmaine Espinosa and I’m a PhD student under Dr. Hans H. Stein. Today, it is my pleasure to talk about some of the research we conducted regarding copper hydroxychloride. Copper has been recognized as an essential mineral since 1928 when it was demonstrated that copper plays an important role in red blood cell synthesis. This discovery led to further research to demonstrate that copper is essential not only for preventing anemia, but is also an important micronutrient needed for maintenance and growth. Copper is an essential component of several metalloenzymes including cytochrome oxidase and lysyl oxidase, and is involved in oxidation-reduction reactions and protection against oxidative stress. Copper is also involved in metabolic reactions including cellular respiration, tissue pigmentation, and hemoglobin formation. The requirement for copper by weanling pigs is 5 to 6 mg/kg in the diet and if this amount is included in diets, deficiency symptoms are not observed, and we expect that animals will be of normal health status. However, copper may also be included at growth promoting levels in diets for weanling and growing pigs. Copper included at a range of 75 to 250 mg/kg in diets for pigs usually improve average daily gain and gain:feed ratio. However, the exact mechanism of copper in exerting these positive effects has not yet been elucidated, but it is believed that it is due to its bacteriostatic and bactericidal properties. Copper sulfate is the most common form of supplemental copper used in animal feeding due to its availability, and is relatively low in cost compared with other inorganic sources of copper. Copper may also be provided in chloride forms. However, the use of high concentration of copper sulfate in swine diets have resulted in environmental concerns due to high excretion of copper in feces. Therefore, other forms of inorganic copper, which are generally included in diets at a lower inclusion rate, have been introduced to the feed industry. An example of this is chelated copper and it is possible that copper from this source is absorbed more efficiently and has higher retention compared with copper sulfate. Another source of inorganic copper is copper hydroxychloride, which is insoluble in water, but greatly soluble in acidic conditions, which makes it less aggressive in vitamin-mineral premixes, and has less prooxidant activity than copper sulfate. There is, however, limited research about the use of copper hydroxychloride when fed to pigs. Therefore, the objective of the two experiments was to test the hypothesis that copper hydroxychloride improves growth performance and reduces incidence of diarrhea in pigs, and also improves blood characteristics that may explain the possible improved changes in pig performance. The first experiment is a growth performance trial. This is the first experiment we conducted in our lab regarding copper hydroxychloride. We wanted to know if copper hydroxychloride exerts some positive effect in our swine research facility. Eighty newly weaned pigs were used in this experiments with four pigs per pen and ten replicate pens per treatment. These pigs were allotted and fed two experimental diets which consist of a control diet based on corn and soybean meal or the control diet plus 150 mg/kg of copper from copper hydroxychloride for four weeks. A two-phase feeding program was used, with days 0 to 14 as phase 1 and days 14 to 28 as phase 2. Diarrhea scores were assessed visually every other day using a score from 1 to 5 being 1 as a normal, hard feces to 5 as watery diarrhea. Data were summarized to calculate average daily gain, average daily feed intake, and gain:feed ratio for each pen and treatment group. Moving on with the results: This graph shows the average daily feed intake and average daily gain of pigs fed the control diet and pigs fed the control diet supplemented with 150 mg/kg of copper from copper hydroxychloride. For the overall experimental period, pigs fed diets with 150 mg/kg of copper as copper hydroxychloride had greater average daily feed intake compared with pigs fed the control diet, which also resulted in pigs fed diets with copper hydroxychloride having greater average daily gain than the control. Pigs fed diets with copper hydroxychloride also had greater gain:feed ration in the overall phase compared with pigs fed diets in the control group. A reduction in diarrhea scores was observed for pigs fed diets with 150 mg/kg of copper compared with pigs fed the control diet. The reduced diarrhea score observed in pigs fed diets containing copper hydroxychloride may be attributed to the bacteriostatic properties of dietary copper, which is believed to affect the growth and community structure of microorganisms in the cecum and colon. Based from the results in this experiment, we therefore conclude that supplementation of 150 mg/kg of copper from copper hydroxychloride improves growth performance and reduces diarrhea incidence. The next experiment is a growth performance trial which involves two levels of copper hydroxychloride and its effect on blood concentrations as indicators for protein utilization and inflammatory response of pigs. 150 pigs were used in this experiment with 5 pigs per pen and 10 replicate pens per treatment. These pigs were allotted and fed three experimental diets which consist of a control diet based on corn and soybean meal, the control diet plus 100 mg/kg of copper from copper hydroxychloride, or the control diet plus 200 mg/kg of copper from copper hydroxychloride for four weeks. Same experimental diets were used for the whole experiment with diarrhea scores being visually assessed every other day using the same scoring system as in the first experiment. On the last day of the experiment, blood samples were collected from one pig per pen to measure blood urea nitrogen, total protein, and albumin. Also, we used ELISA kits to measure the concentration of tumor necrosis facter α as an indicator of inflammatory response, and immunoglobulin A as an indicator of immune response. Data were summarized to calculate average daily gain, average daily feed intake, and gain:feed ratio. Moving on with the results: On the first phase of the experiment, greater average daily gain was observed in pigs fed the copper hydroxychloride diets compared with the control. Likewise, an improvement in gain:feed ration was observed in pigs fed diets with supplemented copper hydroxychloride either at 100 or 200 mg/kg. As a result, greater final body weight was observed in pigs fed diets with copper hydroxychloride compared with the control. A reduction in diarrhea scores was observed in pigs fed the copper hydroxychloride either at 100 or 200 mg/kg in the diet compared with pigs fed the control diet, same as what we observed in the first experiment. There is no difference in the concentration of blood urea nitrogen between pigs fed the control diet and pigs fed diets with supplemental copper. This likely appears that addition of copper hydroxychloride in diets does not affect or change the amino acid utilization and therefore the efficiency of protein synthesis in pigs. The same is true for the concentration of albumin for these pigs. The lack of differences among treatments may indicate that dietary copper concentrations have no effect on the rate of nutrient absorption and on serum protein concentration. In terms of tumor necrosis factor α concentration, there is no difference in pigs fed the control diet and the copper hydroxychloride diets. The same in the case of immunoglobulin A concentrations. And the lack of differences in concentrations of tumor necrosis factor α and immunoglobulin A between pigs fed diets containing copper hydroxychloride and pigs fed the control diet indicates that under the conditions of this experiment, copper hydroxychloride had no impact on the immune status of the pigs. It is possible that this is a result of the fact that pigs with high health status were used in this experiment. So based from the results of the two experiments, we can definitely conclude that copper hydroxychloride, when supplemented to diets at 100 to 200 mg/kg, improves growth performance and reduces incidence of diarrhea. However, it does not affect concentrations of blood proteins, tumor necrosis factor α, or immunoglobulin A of pigs at 6 weeks post-weaning. We would like to take this opportunity to acknowledge Micronutrients and Agrispecialist Inc. for their financial support. Thank you for listening, and if you are interested to know more about our research, you can visit our website at nutrition.ansci.illinois.edu.