Preference of Pigs for Various Sources of Rendered Animal Protein Byproducts

In swine production, voluntary feed consumption is critical for optimal growth of pigs. To illustrate this, the swine industry desires to reduce the utilization of the relatively expensive spray-dried plasma protein (SDPP); however, it is widely included in nursery diets because of its ability to enhance voluntary feed intake of nursery pigs. All protein supplements must compete on a cost basis with conventional soybean meal (SBM) and synthetic amino acids. For more costly protein sources, they must have a unique property that cannot be mimicked by SBM. Animal protein byproducts may uniquely affect feed preference based on the umami flavor, a “meaty” flavor, thereby improving voluntary feed intake of pigs. If given a choice, pigs will clearly demonstrate a feed preference. A feed preference assay is commonly used to quantify the palatability of feedstuffs available for pigs. Previous preference studies conducted at the University of Kentucky reported that nursery pigs exhibit feed preferences for SDPP and dried porcine solubles (DPS), both animal byproducts. Thus, results from the proposed preference studies and subsequent performance studies may identify additional animal byproducts that uniquely affect feed intake in pigs. The research proposed is aimed at verifying the hypothesis that pigs will demonstrate a preference for animal byproducts, leading to improved voluntary feed intake. The optimal inclusion levels and preference of animal byproducts in late nursery pigs will be assessed first, followed by performance studies. This evaluation of the feed preference of pigs has the potential to generate great value to the rendering industry. For instance, assuming alterative byproduct demonstrates a pig preference similar to DPS at 2.5% of the diet and it is confirmed in performance studies, a feed/gain of 1.7 from 24-55 lb bodyweight, a 2.5% inclusion rate in the diet, 100 M pigs marketed/year, and a 40% adoption rate, that equates to 53 M lbs of rendered animal protein byproducts. For grower pigs, the same calculations equate to 126 M lbs of rendered animal protein byproducts.