Depending on personal taste, black licorice, cilantro, olives or hot sauce can be an automatic pass when ordering food. Piglets can be just as selective when it comes to what they want and don’t want to eat. Since consistent feed intake is essential for the gut health and development of piglets after weaning, understanding the factors that influence their decision to eat is essential when formulating diets. Factors that influence piglet feed intake include management practices such as creep feeding, ingredient quality and safety, innate ingredient preferences, antinutrient aversions, and the use of food production technologies to inform somatosensation (mouthfeel).
In natural environments, piglets can use their selective behavior more easily than in production environments where only one feed is provided. The combination of selectivity and lack of control in eating can reduce or even stop food intake, especially during times of stress. Research shows that the consequences of reduced food intake go beyond the disruption of weight gain. A study found that piglets infected orally with Escherichia coli experienced a reduction in feed efficiency only when their feed intake fell below a certain threshold, indicating that adequate feed intake is essential to minimize the risk of gut health disorders.
Poor feed intake can result in weaning piglets on a poor production trajectory throughout their lives. Research indicates that piglet quality at 10 weeks primarily establishes lifetime performance.
Just as improving piglet feed intake can support gut health and performance, it can also support production efficiency. Maintaining feed intake is linked to other key aspects of piglet nutrition, including preventing the supply of pathogenic bacteria, supporting digestion, strengthening the gut barrier function and stabilizing the microbiota and immune system function.
Several practices can promote food intake. From a management perspective, providing piglet-friendly and highly palatable feed before weaning is an important training mechanism to establish and encourage post-weaning feeding behavior and aid in the development of the digestive system. Assessing food palatability criteria is another good practice. The best feed in the world is worth nothing if the piglets don’t eat it.
Consideration of the following palatability elements helps producers ensure that they are providing an appetizing feed that can support the feed intake of piglets.
Pigs have a sophisticated sense of smell developed to detect nutritious ingredients in feed. This ability helps piglets perform rough feed quality control – detecting, for example, whether lipid oxidation has occurred in a feed. Ensuring feed safety and ingredient quality is a simple way to address this feed design factor. Also, ensuring there are no unpleasant odors in food by encapsulating fats and using antioxidants wisely can help avoid this pitfall.
Piglets have a well-developed sense of taste and more taste buds than most other mammals, which creates a complex array of taste receptors along the mouth and oral cavity. Piglets can distinguish a range of flavors including sweet, sour, salty, bitter, and umami; the complex sensory network then interprets these flavors into taste quality. However, the complexity of this system can make it difficult to determine how certain food ingredients will be received, especially when it comes to fiber sources. For example, certain types of oats may help boost food intake, while other fibrous ingredients may contain antinutrients that taste bitter and may decrease food palatability and intake. During evolution, the bitterness of the taste can indicate the presence of a toxin. When evaluating piglets’ responses to specific and individual feed ingredients, it is possible to establish preferred ingredients, including protein sources, grains and organic acids. Some common anti-nutritional ingredients and factors, which can reduce the palatability of foods, are beans containing lectins, cottonseed meal containing gossypol, rapeseed meal containing glucosinolates, and potato protein containing alkaloids .
Additionally, it can be more difficult to determine how piglets will react to the taste of any feed ingredient, as the taste acuity of humans and piglets does not always match. Some studies of food ingredients have shown that humans identify certain sweet compounds, such as the artificial sweetener saccharin, much more strongly than piglets. The discrepancy means that humans are not the best determinants of ingredient taste for piglets. Solving this problem in flows can go through a two-pronged approach. Firstly, bitter tasting ingredients should be avoided and secondly, ingredients tested in pigs and known to provide a positive taste experience should be emphasized, especially in feeds for young pigs.
Peripheral nutrient sensing
In addition to a well-developed sense of smell and taste, pigs also possess receptors for sensing nutrients in the gastrointestinal tract (GIT). This additional sensing capability is known as peripheral nutrient sensing. The sensors are thought to help determine satiety and metabolic regulation of food intake based on connections to the nervous and endocrine systems.
Somatosensing or “mouth feel”
The final area that can trip a diet up into the “I won’t eat this” category is mouthfeel, or the actual sensation of ingesting the food. This aspect of feeding is linked to the nerve pathway of piglets and can trigger the pain centre. This may be an area to consider as piglets’ milk teeth erupt within the first 10 weeks, which means that chewy or crunchy foods can be physically painful to consume.
Although liquid foods can be a way to cope with this difficult time, they tend to require specific formulations to support steady and stable growth. However, previous work focusing on texture has identified that piglets prefer moist feeds to dry feeds and choose hot feeds over cold and soft over hard, so many desirable elements of the diet have been identified. Providing a food that focuses on including positive attributes helps support food intake.
Beyond the palatability issues is the hurdle of piglets transitioning from sow milk to a completely different feed. Young pigs may be prone to food neophobia or distrust of unfamiliar foods and flavors. Periods of stress, such as weaning, can intensify this response, highlighting the importance of providing blended foods in the pre-weaning period (also called complementary foods). A drastic change in feed flavors or palatability, particularly at weaning, can threaten a drop in feed intake, destabilize piglet gut health and impair performance. Using a common set of flavors in all diets can help avoid a drop in food intake after weaning.
decades of in vitro and live research providing information on how piglets decide what to eat led Trouw Nutrition to develop the Milkiwean Vital Start feeding program. The highly palatable diet has been specifically formulated with mouthfeel in mind and has been developed to include a flavor and aroma profile that encourages piglets to eat. Ensuring adequate feed intake is a fundamental strategy to help piglets through the weaning transition.
Selecting a diet that prioritizes feed intake can help protect piglets’ gut health and set the stage for lifelong performance.