More importantly, choosing the right type of copper is necessary in order to increase its availability in the digestive tract, minimize excess excretion into the environment and maximize return for every feed dollar.

The weaning process is a stressful one for piglets. A new environment, penmates and feed source can all impact the feed intake and growth potential of young animals. Meeting their essential nutritional needs during this transition is critical to minimizing stress and maximizing feed efficiency, overall health and performance.

Ensuring proper early nutrition requires careful attention to ration details. Certain elements, although needed only in small amounts, are important for maintaining young animal health. Copper is one of those elements and is essential for a functional immune system and necessary for a variety of processes in the growing animal. It:

• Optimizes nutrient absorption and digestibility
• Functions as an antioxidant to manage oxidative stress
• Acts as an antimicrobial agent and improves gut health
• Contributes to collagen development for tissue and bone health
• Is necessary for normal metabolic function
• Promotes reproductive performance
• Is essential for iron utilization

Recent studies have helped researchers better understand the role of copper in the diet of young pigs.

Dr. Yulin Ma, technical services manager for Novus International

“We’re starting to understand how copper can stimulate a certain gene expression that increases feed intake, which leads to improved gain,” says Dr. Yulin Ma, technical services manager for Novus International. “We’ve found that the improvement of dietary fat digestibility in weanling pigs is related to improved intestinal activity of the enzyme lipase when dietary copper is added.”

Improved daily gain and feed conversion
Ma and colleagues conducted a meta-analysis of published literature on copper supplementation in nursery and growing-finishing pig diets in the United States, including six studies with varying levels of copper inclusion. Their analysis revealed that supplementing nursery pigs with an organic, chelated copper source (metal methionine hydroxy analogue copper chelate, or MMHAC Cu) significantly improved daily gain by 3 percent and feed conversion ratio by 2.6 percent when compared to an inorganic copper sulfate. The incidence of diarrhea was reduced by 23 percent in weaned pigs fed MMHAC Cu, and grower-finisher pigs fed the supplement experienced an improved immune response and improved nutrients digestibility of a basic corn-soybean diet.

In addition to the antibacterial effects of copper, the studies also showed that MMHAC Cu requires lower maintenance for gut turnover due to an improved villus height-to-crypt depth ratio and promotes better nutrient digestion and absorption. Specifically, MMHAC Cu improves the digestibility levels of copper by 42 percent, dry matter by 8 percent, crude protein by 9 percent, phosphorus by 14 percent, energy by 8 percent and fat by 10 percent compared with basal diet. The biggest advantage of feeding MMHAC Cu was observed in pigs in later nursery phases, including pigs 28 days or older and seven kilograms or heavier.

Studies conducted in other areas of the world have shown similar results, notes Ma. “Studies in China, for example, showed improved growth performance, reduced diarrhea and fecal excretion of copper, and improved nutrient digestibility. Brazilian studies showed improved nursery growth performance and significantly increased storage of copper in the liver.”

Understanding the chelation advantage

Trace mineral supplements can perform differently in the animal’s digestive tract. For example, when inorganic salts are used as a copper source, much of the mineral is often excreted and lost in the feces due to chemical antagonisms and interactions with other diet components in the digestive tract. That loss results in continued metabolic deficiencies, but can also lead to spending more than is necessary to over-feed minerals. Chelated minerals help overcome these common digestive challenges.

In scientific terms, chelation means the trace mineral is bound with a ligand.

“This creates a stable complex in the acidic pH of the upper gastrointestinal tract, reduces mineral breakup, helps reduce losses caused by antagonisms and protects the mineral for efficient delivery and uptake in the small intestine,” explains Ma.

Because of this significant difference, a new feed ingredient category was proposed by Novus International, Inc. This category is Metal Methionine Hydroxy Analogue Chelate, or MMHAC.

Gavin Bowman, executive manager, minerals global product development, for Novus International

“The Association of American Feed Control Officials accepted this new definition, which literally makes MINTREX^® Cu chelated copper one of a new class of trace minerals,” says Gavin Bowman, executive manager, minerals global product development, for Novus International.

“What makes MINTREX Cu unique is that it is the only copper chelated with HMTBa (the active ingredient in ALIMET^® feed supplement), a methionine source that helps protect the mineral and gives it greater stability in the animal’s digestive tract,” he explains. “That makes it more bioavailable than both inorganic copper and other organic copper trace minerals.”

Benefits of more bioavailability

Over the years, the majority of trials with weaned pigs have demonstrated performance enhancement when dietary copper exceeded 125-150 ppm, particularly during the first eight weeks after the start of copper supplementation. The challenge has been to avoid excess copper excretion, which poses a significant environmental hazard and is typically caused by the relatively poor availability of copper from inorganic sources.

The key to reducing mineral excretion is to optimize mineral intake by improving its availability.

“That can be accomplished by decreasing the interaction of free minerals with various dietary and digestive components such as phytate and fiber, and by decreasing the opportunity for mineral interactions in the gastrointestinal tract,” explains Bowman. “The most common ways to improve mineral availability are to form a complex with various amino acids or polysaccharides or to formulate chemically stable chelates.”

“In vitro tests with MINTREX Cu clearly show enhanced stability when compared with other mineral sources,” says Bowman. “Trials show that 50 ppm of copper from MINTREX Cu yields similar growth and feed efficiency improvements to 250 ppm of copper from CuSO₄ (Figure 1).

Supplementation strategy

Because organic copper, and specifically chelated copper, is better absorbed by animals than comparable inorganic trace mineral supplements, a producer can feed less mineral while still maintaining feed efficiency. “By substituting inorganic copper sources with organic versions in post-weaning diets, a grower can maintain performance levels, while decreasing the level of copper excretion and lowering the cost of copper supplementation,” says Bowman.

A recent feeding trial provides further evidence. The performance of 924 newly weaned pigs receiving copper supplementation from inorganic sources – copper sulfate (CuSO₄) and tribasic copper chloride (TBCC) – and an organic source – MINTREX Cu fed at two rates – was compared when fed at equal Cu levels the first 21 days post-weaning. The Cu in the control group was solely derived from the ingredients and the basal level of Cu supplied in the trace mineral mix (Table 1).

In general, growth rates for the first seven days post-weaning were improved with all forms of Cu supplementation, although feed intake appeared to be numerically improved with the higher rate of organic Cu (Table 2). During the first 21 days post-weaning, pigs receiving the Cu supplement gained 1.3 to 1.9 pounds more weight than those on the basal diet.

Feed conversion improvements with Cu supplementation ranged from 2.9 percent for pigs fed TBCC to 6.6 percent for pigs receiving CuSO₄ to 13.5 percent for pigs fed MINTREX Cu (Table 3). Study results also demonstrated improved accumulation of Cu in the livers of pigs supplemented with the organic copper form vs. CuSO₄.

“More efficient absorption of organic chelated trace minerals means less mineral is excreted by the animal,” says Bowman. “That’s not just better for the environment, it’s better for the producer’s bottom line."