Functional feed: making trace elements appetizing for pigs
Selko, the Feed Additive brand of Trouw Nutrition, the animal nutrition division of Nutreco, shares research on the role that the trace element source plays in helping or harming the palatability of foods, with particular emphasis on the use of types of trace elements in feed or pre-weaning diets.
Research on palatability in pork has shown that the mineral source influences feed intake. Research shows that reactive mineral sources, like sulfate-based trace minerals, can alter flavor profile and reduce food consumption, especially when high levels are present in pre- and post-weaning diets. The use of less reactive trace elements – such as hydroxychloride trace elements – can support or even improve feed consumption for young pigs. Establishing and sustaining high food consumption early in life can help animals reach their full potential, as evidenced by better adaptation after weaning, as well as greater weight gain earlier and throughout. throughout the production process.
Development of trace elements
As livestock genetics improved, animals began to require higher levels of nutrients than those available in feed ingredients alone. This requirement encourages the use of supplements comprising additive trace elements. Trace mineral types have also seen progress in development since their initial use decades ago. Advances in food additive technologies have improved mineral bond stability and bioavailability while reducing reactivity (Figure 1). Created in the mid-1990s, hydroxychlorinated trace elements provide a more stable covalent bond that does not react with liquid at neutral pH like sulfate-based trace elements. This aspect of insolubility is interesting because weak metal bonds allow trace elements to dissociate and leave free metal ions to interact with other food nutrients and potentially alter the flavor of food. In addition, hydroxy trace elements have a higher metal concentration – 44 to 56% – than organic trace elements and a lower price.
Food palatability – flavor, food intake and feeding frequency
The taste of food, especially for young animals, can be very important because the taste helps stimulate or suppress appetite and food consumption. Ruminants and pigs can both taste different compounds – pigs have more taste catchers or taste buds – than humans, making palatability a priority. While pork can identify a range of flavors including bitter, sweet, sour, fatty, or salty, only certain flavors encourage pigs to keep eating. Other flavors, such as bitter or salty, can cause animals to slow down or stop eating food, increasing the emphasis on palatability – especially in young, learning animals. to eat new foods.
A view of the role played by taste considers the short and long term control of the appetite involved. The short-term control looks at the size of the meal eaten at a given time, while the long-term control examines how often an animal eats or the time that elapses between meals. The taste and palatability of food helps determine how much animals eat, when they eat, how often and how much.
With food consumption, certain flavors, including bitter, sour, and salty tastes, could be linked to issues with the material ingested and often encourage an animal to slow down or stop eating specific foods, which means that these flavor profiles should be avoided. (Figure 2)
Likewise, certain types of trace elements can alter food intake by altering the flavor and palatability of food. Soluble and reactive trace elements, such as oxide and sulfate based minerals, can begin to dissolve in the mouth, releasing metal ions and producing bitter or salty flavors and negatively influencing food intake. Using a more neutral and less reactive source of trace elements may be able to prevent the decline in food intake and potentially improve food intake.
Pig palatability research – information on copper intake in Spain and Kansas, USA
A series of studies have explored the use and palatability of different types of trace elements in pig feed. Early feeding habits help establish good feed intake over the life of a pig. However, early and slow food intake can lead to digestive issues and low levels of copper in the blood, which can lead to developmental issues.
A series of feeding trials carried out at the Universitat Autonoma de Barcelona followed the feed preferences of young pigs.2 In the first feeding trial, the pigs were offered two diets, one containing 15 ppm copper sulfate and the other containing 150 ppm copper sulfate or copper hydroxychloride. In the second, pigs could choose between diets fortified with 150 ppm copper sulfate or 150 ppm hydroxy copper (Figure 3).
Feed test results indicate that when given a choice between diets containing copper sulfate at low (15 ppm) or high (150 ppm) and high levels of hydroxy copper (150 ppm), pigs are more likely to eat foods containing hydroxy copper – especially early in the period. of the trial.
The diets in both trials also contained 500 phytase units and a in vitro an evaluation of the copper source, solubility and interaction with phytase was performed. At a neutral pH, similar to what one would find in the mouth, the copper sulfate dissolved almost completely while the hydroxy copper saw a solubility of less than 20%. However, at a pH of 2.5, such as one would find in the intestine, the copper sulfate and hydroxy copper dissolved completely (Figure 4).
The researchers also monitored the solubility of phytic phosphorus at neutral pH (6.5) in the presence of copper sulfate or hydroxy copper. Copper sulfate reduced the solubility of phytic phosphorus, while its levels remained mostly constant when combined with hydroxy copper. This will allow the added phytase to break down more of the phytic phosphorus, as it is only available to the enzyme when it is in solution.
Likewise, a feeding trial conducted in 2016 tracked the feed consumption and preference of pigs when they received diets containing 160 ppm copper and 110 ppm zinc from a sulfate or hydroxychloride source for a period of 34 days.3 Pigs consumed more feed containing hydroxy-based trace minerals throughout the trial, but were particularly likely to consume the feed on days 0-14.
A study at Kansas State University looked at preferences in older pigs and followed the diet selection of growing-finishing animals.4 in the test, 150 pigs received one of three diets: a control without additional copper and two experimental diets with 150 ppm copper from a sulfate or hydroxychloride source. The pigs were given the choice between control and copper sulfate, control and hydroxy copper, or copper sulfate and hydroxy copper. Palatability test results revealed that pigs preferred the no copper added diet, but that by choosing between the control and a supplemented feed, more were willing to eat the feed containing hydroxy copper. However, when pigs chose between the two supplemented feeds, the diet containing hydroxy copper was almost twice as popular (Figure 5).
Improving the palatability of feed, especially for young pigs, is important for the long-term development and performance of the animal. A 2017 study tracked food intake early in life and found that better food intake before weaning resulted in better daily gain throughout the post-weaning period. 1.6 kg extra.
Improving the palatability of feed before weaning helps establish better feed intake, higher daily gain and improved performance for pigs throughout production. Any increase in food consumption before weaning promotes growth after weaning and can lead to a significant reduction in the total number of days to market.
Since foods contain flavors that animals avoid, food consumption may decrease in the presence of such flavors. These tastes can include bitter, sour and salty flavors, similar to flavors released by highly soluble trace elements. As such, the inclusion of sulfate-based minerals produces an unfavorable response for several species when the additives are present in foods, while the use of less reactive trace elements such as the IntelliBond hydroxychloride minerals can support or increase food intake.
Looking at the results, the researchers concluded that calves and pigs prefer to consume more stable micronutrient sources such as IntelliBond over sulfate or also organic micronutrients through a variety of steps and strategies. supplementation. Increasing preferential intake and palatability through supplementation with stable, non-reactive trace minerals may help achieve better results including higher food intake, daily gain, and also weaning body weight. and after. Research shows that higher weaning weights also translate into higher lifetime performance in pig and ruminant species.